Mesoporous Silica Nanoparticles-Encapsulated Agarose and Heparin as Anticoagulant and Resisting Bacterial Adhesion Coating for Biomedical Silicone.

PubMed

Wu, Fan; Xu, Tingting; Zhao, Guangyao; Meng, Shuangshuang; Wan, Mimi; Chi, Bo; Mao, Chun; Shen, Jian

2017-05-30

Silicone catheter has been widely used in peritoneal dialysis. The research missions of improving blood compatibility and the ability of resisting bacterial adhesion of silicone catheter have been implemented for the biomedical requirements. However, most of modification methods of surface modification were only able to develop the blood-contacting biomaterials with good hemocompatibility. It is difficult for the biomaterials to resist bacterial adhesion. Here, agarose was selected to resist bacterial adhesion, and heparin was chosen to improve hemocompatibility of materials. Both of them were loaded into mesoporous silica nanoparticles (MSNs), which were successfully modified on the silicone film surface via electrostatic interaction. Structures of the mesoporous coatings were characterized in detail by dynamic light scattering, transmission electron microscopy, Brunauer-Emmett-Teller surface area, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscope, and water contact angle. Platelet adhesion and aggregation, whole blood contact test, hemolysis and related morphology test of red blood cells, in vitro clotting time tests, and bacterial adhesion assay were performed to evaluate the anticoagulant effect and the ability of resisting bacterial adhesion of the modified silicone films. Results indicated that silicone films modified by MSNs had a good anticoagulant effect and could resist bacterial adhesion. The modified silicone films have potential as blood-contacting biomaterials that were attributed to their biomedical properties.

Bacterial endotoxin adhesion to different types of orthodontic adhesives

PubMed Central

ROMUALDO, Priscilla Coutinho; GUERRA, Thaís Rodrigues; ROMANO, Fábio Lourenço; da SILVA, Raquel Assed Bezerra; BRANDÃO, Izaíra Tincani; SILVA, Célio Lopes; da SILVA, Lea Assed Bezerra; NELSON-FILHO, Paulo

2017-01-01

Abstract Bacterial endotoxin (LPS) adhesion to orthodontic brackets is a known contributing factor to inflammation of the adjacent gingival tissues. Objective The aim of this study was to assess whether LPS adheres to orthodontic adhesive systems, comparing two commercial brands. Material and Methods Forty specimens were fabricated from Transbond XT and Light Bond composite and bonding agent components (n=10/component), then contaminated by immersion in a bacterial endotoxin solution. Contaminated and non-contaminated acrylic resin samples were used as positive and negative control groups, respectively. LPS quantification was performed by the Limulus Amebocyte Lysate QCL-1000™ test. Data obtained were scored and subjected to the Chi-square test using a significance level of 5%. Results There was endotoxin adhesion to all materials (p<0.05). No statistically significant difference was found between composites/bonding agents and acrylic resin (p>0.05). There was no significant difference (p>0.05) among commercial brands. Affinity of endotoxin was significantly greater for the bonding agents (p=0.0025). Conclusions LPS adhered to both orthodontic adhesive systems. Regardless of the brand, the endotoxin had higher affinity for the bonding agents than for the composites. There is no previous study assessing the affinity of LPS for orthodontic adhesive systems. This study revealed that LPS adheres to orthodontic adhesive systems. Therefore, additional care is recommended to orthodontic applications of these materials. PMID:28877283

Adhesion of mutans streptococci to self-ligating ceramic brackets: in vivo quantitative analysis with real-time polymerase chain reaction.

PubMed

Jung, Woo-Sun; Yang, Il-Hyung; Lim, Won Hee; Baek, Seung-Hak; Kim, Tae-Woo; Ahn, Sug-Joon

2015-12-01

To analyze in vivo mutans streptococci (MS) adhesion to self-ligating ceramic brackets [Clarity-SL (CSL) and Clippy-C (CC)] and the relationships between bacterial adhesion and oral hygiene indices. Four central incisor brackets from the maxilla and mandible were collected from 40 patients (20 patients per each bracket type) at debonding immediately after plaque and gingival indices were measured. Adhesions of Streptococcus mutans, S. sobrinus, and total bacteria were quantitatively determined using real-time polymerase chain reaction after genomic DNA was extracted. Factorial analysis of variance was used to analyze bacterial adhesion to the brackets with respect to the bracket type and jaw position. Correlation coefficients were calculated to determine the relationships of bacterial adhesion to oral hygiene indices. Adhesion of total bacteria and S. mutans to CSL was higher than that to CC (P < 0.001). Adhesion of total bacteria to the mandibular brackets was higher than that to the maxillary ones (P < 0.001), while adhesion of S. mutans to the maxillary brackets were higher than that in the mandibular ones (P < 0.001). In particular, the proportion of S. mutans to total bacteria in CSL was higher than CC (P < 0.05) in the maxillary anterior teeth (P < 0.001). There were no significant differences in adhesion of S. sobrinus between the brackets and jaw positions. Interestingly, no significant relationships were found between bacterial adhesions and oral hygiene indices. Complex bracket configurations may significantly influence bacterial adhesion to orthodontic brackets. Further in vivo study using bracket raw materials will help to define the relationships between bacteria adhesion and enamel demineralization. Because oral hygiene indices were not significantly correlated with adhesions of MS to self-ligating ceramic brackets, careful examinations around the brackets should be needed to prevent enamel demineralization, regardless of oral hygiene status. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Bacterial Adhesion on the Titanium and Stainless-Steel Surfaces Undergone Two Different Treatment Methods: Polishing and Ultrafast Laser Treatment

NASA Astrophysics Data System (ADS)

Chik, N.; Zain, W. S. Wan Md; Mohamad, A. J.; Sidek, M. Z.; Ibrahim, W. H. Wan; Reif, A.; Rakebrandt, J. H.; Pfleging, W.; Liu, X.

2018-05-01

Bacterial adhesion has become a significant problem in many industries causing billions of dollars for its complicated removal treatment and maintenance. In this study, metal surfaces undergone treatment with ultrafast laser with varies power. The microstructure produced on its original surfaces were expected to prevent the adhesion of Escherichia coli (E. coli) ATCC 8739 and Staphylococcus aureus (S. aureus) ATCC 6838. The laser treatment was performed at 380 fs pulse duration, 515 µm central wavelength and a repetition rate of 200 kHz. Stainless steel AISI 316L was treated with an average laser power of 0.04 W (SS-0.04) and 0.11 W (SS-0.11), while Grade 5 titanium alloy was tested with high laser power 0.11 W (T-0.11). The adhesion was observed after 16 hours and the number of adhering bacteria was counted per cm2. The result achieved shows that, increasing the average laser power is leading to an enhanced S. aureus adhesion while E. coli adhesion is reduced which is due to the hydrophobicity interaction and difference in surface texture. Meanwhile, the laser treatment showed significant reduction of the bacterial adhesion on its surface compared to the polished surfaces. Thus, ultrafast laser texturing can be suggested as a promising method to reduce the bacterial adhesion, which reduced the adhesion of >80% for E. coli and >20% for S. aureus.

Determination of the nano-scaled contact area of staphylococcal cells.

PubMed

Spengler, Christian; Thewes, Nicolas; Jung, Philipp; Bischoff, Markus; Jacobs, Karin

2017-07-20

Bacterial adhesion is a crucial step during the development of infections as well as the formation of biofilms. Hence, fundamental research of bacterial adhesion mechanisms is of utmost importance. So far, less is known about the size of the contact area between bacterial cells and a surface. This gap will be filled by this study using a single-cell force spectroscopy-based method to investigate the contact area between a single bacterial cell of Staphylococcus aureus and a solid substrate. The technique relies on the strong influence of the hydrophobic interaction on bacterial adhesion: by incrementally crossing a very sharp hydrophobic/hydrophilic interface while performing force-distance curves with a single bacterial probe, the bacterial contact area can be determined. Assuming circular contact areas, their radii - determined in our experiments - are in the range from tens of nanometers to a few hundred nanometers. The contact area can be slightly enlarged by a larger load force, yet does not resemble a Hertzian contact, rather, the enlargement is a property of the individual bacterial cell. Additionally, Staphylococcus carnosus has been probed, which is less adherent than S. aureus, yet both bacteria exhibit a similar contact area size. This corroborates the notion that the adhesive strength of bacteria is not a matter of contact area, but rather a matter of which and how many molecules of the bacterial species' cell wall form the contact. Moreover, our method of determining the contact area can be applied to other microorganisms and the results might also be useful for studies using nanoparticles covered with soft, macromolecular coatings.

New method to study bacterial adhesion to meat.

PubMed Central

Piette, J P; Idziak, E S

1989-01-01

A new method was developed for the study of bacterial adhesion to meat surfaces. Thin slices of meat (40 microns thick) were inserted into a specially designed observation chamber. The meat slices were then exposed to a bacterial suspension (ca. 10(6) CFU.ml-1) to initiate adhesion (20 min of contact time) and subsequently rinsed to eliminate nonadherent bacteria. Because of the special chamber design, the disruptive force exerted on the bacteria during rinsing (shear stress) was uniform over the whole surface of the meat slices, was constant, and could be varied from 0 to 0.08 N.m-2. After being rinsed, the meat slices were stained with basic fuschin and observed under light microscopy to determine the number and distribution of adherent bacteria. This new method was used to study the adhesion of Acinetobacter strain LD2, a Lactobacillus sp., and Pseudomonas fluorescens to slices of beef fat and tendon. At 25 degrees C, most (greater than or equal to 99.9%) of the cells of the Lactobacillus sp. deposited on the meat were washed off the surface during rinsing (0.05 N.m-2), whereas a large number (ca. 10(5) CFU.cm-2) of Acinetobacter strain LD2 and P. fluorescens cells remained adherent. The extent of adhesion was similar on fat and tendon, and adherent bacteria were distributed evenly over the whole surface of the slices. This preliminary study indicates that the combined use of thin slices of meat and of the observation chamber provides us with the means to more accurately study bacterial adhesion to meat surfaces. Images PMID:2764565

Atomic force microscopy-guided fractionation reveals the influence of cranberry phytochemicals on adhesion of Escherichia coli.

PubMed

Gupta, Prachi; Song, Biqin; Neto, Catherine; Camesano, Terri A

2016-06-15

Cranberry juice has been long used to prevent infections because of its effect on the adhesion of the bacteria to the host surface. Proanthocyanidins (PACs) comprise of one of the major classes of phytochemicals found in cranberry, which have been extensively studied and found effective in combating adhesion of pathogenic bacteria. The role of other cranberry constituents in impacting bacterial adhesion haven't been studied very well. In this study, cranberry juice fractions were prepared, characterized and tested for their effect on the surface adhesion of the pathogenic clinical bacterial strain E. coli B78 and non-pathogenic control E. coli HB101. The preparations tested included crude cranberry juice extract (CCE); three fractions containing flavonoid classes including proanthocyanidins, anthocyanins and flavonols; selected sub-fractions, and commercially available flavonol glycoside, quercetin-3-O-galactoside. Atomic force microscopy (AFM) was used to quantify the adhesion forces between the bacterial surface and the AFM probe after the treatment with the cranberry fractions. Adhesion forces of the non-pathogenic, non fimbriated lab strain HB101 are small (average force 0.19 nN) and do not change with cranberry treatments, whereas the adhesion forces of the pathogenic, Dr adhesion E. coli strain B78 (average force of 0.42 nN) show a significant decrease when treated with cranberry juice extract or fractions (average force of 0.31 nN, 0.37 nN and 0.39 nN with CCE, Fraction 7 and Fraction 4 respectively). In particular, the fractions that contained flavonols in addition to PACs were more efficient at lowering the force of adhesion (average force of 0.31 nN-0.18 nN between different sub-fractions containing flavonols and PACs). The sub-fractions containing flavonol glycosides (from juice, fruit and commercial quercetin) all resulted in reduced adhesion of the pathogenic bacteria to the model probe. This strongly suggests the anti adhesive role of other classes of cranberry compounds in conjunction with already known PACs and may have implications for development of alternative anti bacterial treatments.

Competition of bovine serum albumin adsorption and bacterial adhesion onto surface-grafted ODT: in situ study by vibrational SFG and fluorescence confocal microscopy.

PubMed

Bulard, Emilie; Fontaine-Aupart, Marie-Pierre; Dubost, Henri; Zheng, Wanquan; Bellon-Fontaine, Marie-Noëlle; Herry, Jean-Marie; Bourguignon, Bernard

2012-12-11

The interaction of hydrophilic and hydrophobic ovococcoid bacteria and bovine serum albumin (BSA) proteins with a well ordered surface of octadecanethiol (ODT) self assembled monolayer (SAM) has been studied in different situations where proteins were either preadsorbed on ODT or adsorbed simultaneously with bacterial adhesion as in life conditions. The two situations lead to very different antimicrobial behavior. Bacterial adhesion on preadsorbed BSA is very limited, while the simultaneous exposure of ODT SAM to proteins and bacteria lead to a markedly weaker antimicrobial effect. The combination of sum frequency generation spectroscopy and fluorescence confocal microscopy experiments allow one to draw conclusions on the factors that govern the ODT SAM or BSA film interaction with bacteria at the molecular level. On the hydrophobic ODT surface, interaction with hydrophobic or hydrophilic biomolecules results in opposite effects on the SAM, namely, a flattening or a raise of the terminal methyl groups of ODT. On an amphiphilic BSA layer, the bacterial adhesion strength is weakened by the negative charges carried by both BSA and bacteria. Surprisingly, preadsorbed BSA that cover part of the bacteria cell walls increase the adhesion strength to the BSA film and reduce hydrophobic interactions with the ODT SAM. Finally, bacterial adhesion on a BSA film is shown to modify the BSA proteins in some way that change their interaction with the ODT SAM. The antimicrobial effect is much stronger in the case of a preadsorbed BSA layer than when BSA and bacteria are in competition to colonize the ODT SAM surface.

Surface zwitterionization: Effective method for preventing oral bacterial biofilm formation on hydroxyapatite surfaces

NASA Astrophysics Data System (ADS)

Lee, Myoungjin; Kim, Heejin; Seo, Jiae; Kang, Minji; Kang, Sunah; Jang, Joomyung; Lee, Yan; Seo, Ji-Hun

2018-01-01

In this study, we conducted surface zwitterionization of hydroxyapatite (HA) surfaces by immersing them in the zwitterionic polymer solutions to provide anti-bacterial properties to the HA surface. Three different monomers containing various zwitterionic groups, i.e., phosphorylcholine (PC), sulfobetaine (SB), and carboxybetaine (CB), were copolymerized with the methacrylic monomer containing a Ca2+-binding moiety, using the free radical polymerization method. As a control, functionalization of the copolymer containing the Ca2+-binding moiety was synthesized using a hydroxy group. The stable immobilization of the zwitterionic functional groups was confirmed by water contact angle analysis and X-ray photoelectron spectroscopy (XPS) measurement conducted after the sonication process. The zwitterionized HA surface showed significantly decreased protein adsorption, whereas the hydroxyl group-coated HA surface showed limited efficacy. The anti-bacterial adhesion property was confirmed by conducting Streptococcus mutans (S. mutans) adhesion tests for 6 h and 24 h. When furanone C-30, a representative anti-quorum sensing molecule for S. mutans, was used, only a small amount of bacteria adhered after 6 h and the population did not increase after 24 h. In contrast, zwitterionized HA surfaces showed almost no bacterial adhesion after 6 h and the effect was retained for 24 h, resulting in the lowest level of oral bacterial adhesion. These results confirm that surface zwitterionization is a promising method to effectively prevent oral bacterial adhesion on HA-based materials.

Influence of adhesion to activated carbon particles on the viability of waterborne pathogenic bacteria under flow.

PubMed

van der Mei, Henny C; Atema-Smit, Jelly; Jager, Debbie; Langworthy, Don E; Collias, Dimitris I; Mitchell, Michael D; Busscher, Henk J

2008-07-01

In rural areas around the world, people often rely on water filtration plants using activated carbon particles for safe water supply. Depending on the carbon surface, adhering microorganisms die or grow to form a biofilm. Assays to assess the efficacy of activated carbons in bacterial removal do not allow direct observation of bacterial adhesion and the determination of viability. Here we propose to use a parallel plate flow chamber with carbon particles attached to the bottom plate to study bacterial adhesion to individual carbon particles and determine the viability of adhering bacteria. Observation and enumeration is done after live/dead staining in a confocal laser scanning microscope. Escherichiae coli adhered in higher numbers than Raoultella terrigena, except to a coconut-based carbon, which showed low bacterial adhesion compared to other wood-based carbon types. After adhesion, 83-96% of the bacteria adhering to an acidic carbon were dead, while on a basic carbon 54-56% were dead. A positively charged, basic carbon yielded 76-78% bacteria dead, while on a negatively charged coconut-based carbon only 32-37% were killed upon adhesion. The possibility to determine both adhesion as well as the viability of adhering bacteria upon adhesion to carbon particles is most relevant, because if bacteria adhere but remain viable, this still puts the water treatment system at risk, as live bacteria can grow and form a biofilm that can then be shedded to cause contamination. (c) 2008 Wiley Periodicals, Inc.

Plasma surface modification of rigid contact lenses decreases bacterial adhesion.

PubMed

Wang, Yingming; Qian, Xuefeng; Zhang, Xiaofeng; Xia, Wei; Zhong, Lei; Sun, Zhengtai; Xia, Jing

2013-11-01

Contact lens safety is an important topic in clinical studies. Corneal infections usually occur because of the use of bacteria-carrying contact lenses. The current study investigated the impact of plasma surface modification on bacterial adherence to rigid contact lenses made of fluorosilicone acrylate materials. Boston XO and XO2 contact lenses were modified using plasma technology (XO-P and XO2-P groups). Untreated lenses were used as controls. Plasma-treated and control lenses were incubated in solutions containing Staphylococcus aureus or Pseudomonas aeruginosa. MTT colorimetry, colony-forming unit counting method, and scanning electron microscopy were used to measure bacterial adhesion. MTT colorimetry measurements showed that the optical density (OD) values of XO-P and XO2-P were significantly lower than those of XO and XO2, respectively, after incubation with S. aureus (P < 0.01). The OD value of XO-P was also much lower than that of XO after incubation with P. aeruginosa (P < 0.01). Colony-forming unit counting revealed that a significantly lower number of bacterial colonies attached to the XO-P versus XO lenses and to the XO2-P versus XO2 lenses incubated with S. aureus (P < 0.01). Fewer bacterial colonies attached to the XO-P versus XO lenses incubated with P. aeruginosa (P < 0.01). Further, scanning electron microscopy suggested different bacterial adhesion morphology on plasma-treated versus control lenses. Plasma surface modification can significantly decrease bacterial adhesion to fluorosilicone acrylate contact lenses. This study provides important evidence of a unique benefit of plasma technology in contact lens surface modification.

Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane.

PubMed

Tupinambá, Rogerio Amaral; Claro, Cristiane Aparecida de Assis; Pereira, Cristiane Aparecida; Nobrega, Celestino José Prudente; Claro, Ana Paula Rosifini Alves

2017-01-01

Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Significant statistical differences (p< 0.05) for surface roughness and bacterial adhesion reduction were observed on conventional brackets after surface treatment and between conventional and self-ligating brackets; no significant statistical differences were observed between self-ligating groups (p> 0.05). Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film.

Adhesion force of staphylococcus aureus on various biomaterial surfaces.

PubMed

Alam, Fahad; Balani, Kantesh

2017-01-01

Staphylococcus comprises of more than half of all pathogens in orthopedic implant infections and they can cause major bone infection which can result in destruction of joint and bone. In the current study, adhesion force of bacteria on the surface of various biomaterial surfaces is measured using atomic force microscope (AFM). Staphylococcus aureus was immobilized on an AFM tipless cantilever as a force probe to measure the adhesion force between bacteria and biomaterials (viz. ultra-high molecular weight poly ethylene (UHMWPE), stainless steel (SS), Ti-6Al-4V alloy, hydroxyapatite (HA)). At the contact time of 10s, UHMWPE shows weak adhesion force (~4nN) whereas SS showed strong adhesion force (~15nN) due to their surface energy and surface roughness. Bacterial retention and viability experiment (3M™ petrifilm test, agar plate) dictates that hydroxyapatite shows the lowest vaibility of bacteria, whereas lowest bacterial retention is observed on UHMWPE surface. Similar results were obtained from live/dead staining test, where HA shows 65% viability, whereas on UHMWPE, SS and Ti-6Al-4V, the bacterial viability is 78%, 94% and 97%, respectively. Lower adhesion forces, constrained pull-off distance (of bacterial) and high antibacterial resistance of bioactive-HA makes it a potential biomaterial for bone-replacement arthroplasty. Copyright © 2016 Elsevier Ltd. All rights reserved.

Adhesion of bacterial pathogens to soil colloidal particles: influences of cell type, natural organic matter, and solution chemistry.

PubMed

Zhao, Wenqiang; Walker, Sharon L; Huang, Qiaoyun; Cai, Peng

2014-04-15

Bacterial adhesion to granular soil particles is well studied; however, pathogen interactions with naturally occurring colloidal particles (<2 μm) in soil has not been investigated. This study was developed to identify the interaction mechanisms between model bacterial pathogens and soil colloids as a function of cell type, natural organic matter (NOM), and solution chemistry. Specifically, batch adhesion experiments were conducted using NOM-present, NOM-stripped soil colloids, Streptococcus suis SC05 and Escherichia coli WH09 over a wide range of solution pH (4.0-9.0) and ionic strength (IS, 1-100 mM KCl). Cell characterization techniques, Freundlich isotherm, and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory (sphere-sphere model) were utilized to quantitatively determine the interactions between cells and colloids. The adhesion coefficients (Kf) of S. suis SC05 to NOM-present and NOM-stripped soil colloids were significantly higher than E. coli WH09, respectively. Similarly, Kf values of S. suis SC05 and E. coli WH09 adhesion to NOM-stripped soil colloids were greater than those colloids with NOM-present, respectively, suggesting NOM inhibits bacterial adhesion. Cell adhesion to soil colloids declined with increasing pH and enhanced with rising IS (1-50 mM). Interaction energy calculations indicate these adhesion trends can be explained by DLVO-type forces, with S. suis SC05 and E. coli WH09 being weakly adhered in shallow secondary energy minima via polymer bridging and charge heterogeneity. S. suis SC05 adhesion decreased at higher IS 100 mM, which is attributed to the change of hydrophobic effect and steric repulsion resulted from the greater presence of extracellular polymeric substances (EPS) on S. suis SC05 surface as compared to E. coli WH09. Hence, pathogen adhesion to the colloidal material is determined by a combination of DLVO, charge heterogeneity, hydrophobic and polymer interactions as a function of solution chemistry. Copyright © 2014 Elsevier Ltd. All rights reserved.

Adhesion of periodontal pathogens to self-ligating orthodontic brackets: An in-vivo prospective study.

PubMed

Jung, Woo-Sun; Kim, Kyungsun; Cho, Soha; Ahn, Sug-Joon

2016-09-01

Our aims were to analyze adhesion of periodontopathogens to self-ligating brackets (Clarity-SL [CSL], Clippy-C [CC] and Damon Q [DQ]) and to identify the relationships between bacterial adhesion and oral hygiene indexes. Central incisor brackets from the maxilla and mandible were collected from 60 patients at debonding after the plaque and gingival indexes were measured. Adhesions of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Fusobacterium nucleatum (Fn), and Tannerella forsythia (Tf) were quantitatively determined using real-time polymerase chain reactions. Factorial analysis of variance was used to analyze bacterial adhesion in relation to bracket type and jaw position. Correlation coefficients were calculated to determine the relationships between bacterial adhesion and the oral hygiene indexes. Total bacteria showed greater adhesion to CSL than to DQ brackets, whereas Aa, Pg, and Pi adhered more to DQ than to CSL brackets. CC brackets showed an intermediate adhesion pattern between CSL and DQ brackets, but it did not differ significantly from either bracket type. Adhesion of Fn and Tf did not differ significantly among the 3 brackets. Most bacteria were detected in greater quantities in the mandibular than in the maxillary brackets. The plaque and gingival indexes were not strongly correlated with bacterial adhesion to the brackets. Because Aa, Pg, and Pi adhered more to the DQ brackets in the mandibular area, orthodontic patients with periodontal problems should be carefully monitored in the mandibular incisors where the distance between the bracket and the gingiva is small, especially when DQ brackets are used. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Surface thermodynamics and adhesion forces governing bacterial transmission in contact lens related microbial keratitis.

PubMed

Qu, Wenwen; Busscher, Henk J; Hooymans, Johanna M M; van der Mei, Henny C

2011-06-15

Contact lens induced microbial keratitis results from bacterial transmission from one surface to another. We investigated the adhesion forces of Pseudomonas aeruginosa, Staphylococci and Serratia to different contact lenses, lens cases and corneal surfaces using AFM, and applied a Weibull analysis on these adhesion forces to calculate bacterial transmission probabilities from lens case to corneas with a contact lens as an intermediate. Also a new surface thermodynamic parameter was introduced, the interfacial free energy of transmission, which in essence compares the interfacial free energies of bacterial adhesion, calculated from measured contact angles with liquids on the donating and receiving surfaces in the transmission process. Bacterial adhesion forces were generally strongest among all eight strains for the lens case (-6.5 to -12.0 nN) and corneas (-3.5 to -11.5 nN), while contact lenses (-0.6 to -13.1 nN) exerted slightly smaller adhesion forces. Consequently, bacterial transmission from lens case to contact lens yielded a smaller contribution in the final transmission than from contact lens to cornea. Bacterial transmission probabilities as derived from force analyses were higher when the interfacial free energies of transmission were more negative, which is in line with surface thermodynamic principles. Therewith this parameter could provide useful in analyzing other bacterial transmission phenomena between donating and receiving surfaces as well. Copyright © 2011 Elsevier Inc. All rights reserved.

Preparation and evaluation of polysaccharide sulfates for inhibiting Helicobacter pylori adhesion.

PubMed

Song, Weijuan; Wang, Yalong; Zhang, Liyan; Fu, Shengnan; Zeng, Ying; Hu, Haiyan

2014-03-15

In treatments of Helicobacter pylori infections, recrudescences were common because of an unfavorable bacterial eradication rate due to the ever increasing resistance to antibiotics. In this study, we chose pectin, guar gum and chitosan to synthesize their sulfates to inhibit adhesions of H. pylori and thus enhance the eradication rate. The introduction of sulfates was characterized using FT-IR and elemental analysis. Data from zeta-potential, hydrodynamic diameter, hydrolysis and rheological property demonstrated the sulfates were physicochemically stable. Inhibition assay of hemagglutination and adhesion indicated sulfates prevented H. pylori from adhering to erythrocytes and AGS cells. In binding assay, affinities of sulfates to H. pylori suggested sulfates could compete with target cells for bacteria and moderated the bacterial adhesion to hosts. A higher content of galactoses and 2,3-O-linked sulfates benefited this action. Thus polysaccharide sulfates can serve as potential adjuvants to raise the bacterial eradication rate by inhibiting adhesions of H. pylori. Copyright © 2013 Elsevier Ltd. All rights reserved.

Surface physicochemical properties at the micro and nano length scales: role on bacterial adhesion and Xylella fastidiosa biofilm development.

PubMed

Lorite, Gabriela S; Janissen, Richard; Clerici, João H; Rodrigues, Carolina M; Tomaz, Juarez P; Mizaikoff, Boris; Kranz, Christine; de Souza, Alessandra A; Cotta, Mônica A

2013-01-01

The phytopathogen Xylella fastidiosa grows as a biofilm causing vascular occlusion and consequently nutrient and water stress in different plant hosts by adhesion on xylem vessel surfaces composed of cellulose, hemicellulose, pectin and proteins. Understanding the factors which influence bacterial adhesion and biofilm development is a key issue in identifying mechanisms for preventing biofilm formation in infected plants. In this study, we show that X. fastidiosa biofilm development and architecture correlate well with physicochemical surface properties after interaction with the culture medium. Different biotic and abiotic substrates such as silicon (Si) and derivatized cellulose films were studied. Both biofilms and substrates were characterized at the micro- and nanoscale, which corresponds to the actual bacterial cell and membrane/ protein length scales, respectively. Our experimental results clearly indicate that the presence of surfaces with different chemical composition affect X. fastidiosa behavior from the point of view of gene expression and adhesion functionality. Bacterial adhesion is facilitated on more hydrophilic surfaces with higher surface potentials; XadA1 adhesin reveals different strengths of interaction on these surfaces. Nonetheless, despite different architectural biofilm geometries and rates of development, the colonization process occurs on all investigated surfaces. Our results univocally support the hypothesis that different adhesion mechanisms are active along the biofilm life cycle representing an adaptation mechanism for variations on the specific xylem vessel composition, which the bacterium encounters within the infected plant.

Surface Physicochemical Properties at the Micro and Nano Length Scales: Role on Bacterial Adhesion and Xylella fastidiosa Biofilm Development

PubMed Central

Lorite, Gabriela S.; Janissen, Richard; Clerici, João H.; Rodrigues, Carolina M.; Tomaz, Juarez P.; Mizaikoff, Boris; Kranz, Christine; de Souza, Alessandra A.; Cotta, Mônica A.

2013-01-01

The phytopathogen Xylella fastidiosa grows as a biofilm causing vascular occlusion and consequently nutrient and water stress in different plant hosts by adhesion on xylem vessel surfaces composed of cellulose, hemicellulose, pectin and proteins. Understanding the factors which influence bacterial adhesion and biofilm development is a key issue in identifying mechanisms for preventing biofilm formation in infected plants. In this study, we show that X. fastidiosa biofilm development and architecture correlate well with physicochemical surface properties after interaction with the culture medium. Different biotic and abiotic substrates such as silicon (Si) and derivatized cellulose films were studied. Both biofilms and substrates were characterized at the micro- and nanoscale, which corresponds to the actual bacterial cell and membrane/ protein length scales, respectively. Our experimental results clearly indicate that the presence of surfaces with different chemical composition affect X. fastidiosa behavior from the point of view of gene expression and adhesion functionality. Bacterial adhesion is facilitated on more hydrophilic surfaces with higher surface potentials; XadA1 adhesin reveals different strengths of interaction on these surfaces. Nonetheless, despite different architectural biofilm geometries and rates of development, the colonization process occurs on all investigated surfaces. Our results univocally support the hypothesis that different adhesion mechanisms are active along the biofilm life cycle representing an adaptation mechanism for variations on the specific xylem vessel composition, which the bacterium encounters within the infected plant. PMID:24073256

Bacterial adhesion force quantification by fluidic force microscopy

NASA Astrophysics Data System (ADS)

Potthoff, Eva; Ossola, Dario; Zambelli, Tomaso; Vorholt, Julia A.

2015-02-01

Quantification of detachment forces between bacteria and substrates facilitates the understanding of the bacterial adhesion process that affects cell physiology and survival. Here, we present a method that allows for serial, single bacterial cell force spectroscopy by combining the force control of atomic force microscopy with microfluidics. Reversible bacterial cell immobilization under physiological conditions on the pyramidal tip of a microchanneled cantilever is achieved by underpressure. Using the fluidic force microscopy technology (FluidFM), we achieve immobilization forces greater than those of state-of-the-art cell-cantilever binding as demonstrated by the detachment of Escherichia coli from polydopamine with recorded forces between 4 and 8 nN for many cells. The contact time and setpoint dependence of the adhesion forces of E. coli and Streptococcus pyogenes, as well as the sequential detachment of bacteria out of a chain, are shown, revealing distinct force patterns in the detachment curves. This study demonstrates the potential of the FluidFM technology for quantitative bacterial adhesion measurements of cell-substrate and cell-cell interactions that are relevant in biofilms and infection biology.Quantification of detachment forces between bacteria and substrates facilitates the understanding of the bacterial adhesion process that affects cell physiology and survival. Here, we present a method that allows for serial, single bacterial cell force spectroscopy by combining the force control of atomic force microscopy with microfluidics. Reversible bacterial cell immobilization under physiological conditions on the pyramidal tip of a microchanneled cantilever is achieved by underpressure. Using the fluidic force microscopy technology (FluidFM), we achieve immobilization forces greater than those of state-of-the-art cell-cantilever binding as demonstrated by the detachment of Escherichia coli from polydopamine with recorded forces between 4 and 8 nN for many cells. The contact time and setpoint dependence of the adhesion forces of E. coli and Streptococcus pyogenes, as well as the sequential detachment of bacteria out of a chain, are shown, revealing distinct force patterns in the detachment curves. This study demonstrates the potential of the FluidFM technology for quantitative bacterial adhesion measurements of cell-substrate and cell-cell interactions that are relevant in biofilms and infection biology. Electronic supplementary information (ESI) available: Video S1. Detachment of a S. pyogenes cell chain from glass substrate. The cantilever is approached on the outermost adherent cell of a chain and four bacteria were then sequentially detached. The sequential cell detachment suddenly stopped after four bacteria. This possibly occurred because bacteria-glass interactions became too strong or the maximal probe retraction was reached. The cells spontaneously detached from the cantilever flipping back on the surface. Fig. S1. (A) Adhesion force-distance and (B) adhesion force-detaching work correlation of E.coli on PLL for setpoints of 1 and 10 nN. Circle: 1 nN setpoint, square: 10 nN. See DOI: 10.1039/c4nr06495j

Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane

PubMed Central

Tupinambá, Rogerio Amaral; Claro, Cristiane Aparecida de Assis; Pereira, Cristiane Aparecida; Nobrega, Celestino José Prudente; Claro, Ana Paula Rosifini Alves

2017-01-01

ABSTRACT Introduction: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Methods: Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Results: Significant statistical differences (p< 0.05) for surface roughness and bacterial adhesion reduction were observed on conventional brackets after surface treatment and between conventional and self-ligating brackets; no significant statistical differences were observed between self-ligating groups (p> 0.05). Conclusion: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film. PMID:28902253

Infection of orthopedic implants with emphasis on bacterial adhesion process and techniques used in studying bacterial-material interactions

PubMed Central

Ribeiro, Marta; Monteiro, Fernando J.; Ferraz, Maria P.

2012-01-01

Staphylococcus comprises up to two-thirds of all pathogens in orthopedic implant infections and they are the principal causative agents of two major types of infection affecting bone: septic arthritis and osteomyelitis, which involve the inflammatory destruction of joint and bone. Bacterial adhesion is the first and most important step in implant infection. It is a complex process influenced by environmental factors, bacterial properties, material surface properties and by the presence of serum or tissue proteins. Properties of the substrate, such as chemical composition of the material, surface charge, hydrophobicity, surface roughness and the presence of specific proteins at the surface, are all thought to be important in the initial cell attachment process. The biofilm mode of growth of infecting bacteria on an implant surface protects the organisms from the host immune system and antibiotic therapy. The research for novel therapeutic strategies is incited by the emergence of antibiotic-resistant bacteria. This work will provide an overview of the mechanisms and factors involved in bacterial adhesion, the techniques that are currently being used studying bacterial-material interactions as well as provide insight into future directions in the field. PMID:23507884

ZnO nanoparticle incorporated nanostructured metallic titanium for increased mesenchymal stem cell response and antibacterial activity

NASA Astrophysics Data System (ADS)

Elizabeth, Elmy; Baranwal, Gaurav; Krishnan, Amit G.; Menon, Deepthy; Nair, Manitha

2014-03-01

Recent trends in titanium implants are towards the development of nanoscale topographies that mimic the nanoscale properties of bone tissue. Although the nanosurface promotes the integration of osteoblast cells, infection related problems can also occur, leading to implant failure. Therefore it is imperative to reduce bacterial adhesion on an implant surface, either with or without the use of drugs/antibacterial agents. Herein, we have investigated two different aspects of Ti surfaces in inhibiting bacterial adhesion and concurrently promoting mammalian cell adhesion. These include (i) the type of nanoscale topography (Titania nanotube (TNT) and Titania nanoleaf (TNL)) and (ii) the presence of an antibacterial agent like zinc oxide nanoparticles (ZnOnp) on Ti nanosurfaces. To address this, periodically arranged TNT (80-120 nm) and non-periodically arranged TNL surfaces were generated by the anodization and hydrothermal techniques respectively, and incorporated with ZnOnp of different concentrations (375 μM, 750 μM, 1.125 mM and 1.5 mM). Interestingly, TNL surfaces decreased the adherence of staphylococcus aureus while increasing the adhesion and viability of human osteosarcoma MG63 cell line and human mesenchymal stem cells, even in the absence of ZnOnp. In contrast, TNT surfaces exhibited an increased bacterial and mammalian cell adhesion. The influence of ZnOnp on these surfaces in altering the bacterial and cell adhesion was found to be concentration dependent, with an optimal range of 375-750 μM. Above 750 μM, although bacterial adhesion was reduced, cellular viability was considerably affected. Thus our study helps us to infer that nanoscale topography by itself or its combination with an optimal concentration of antibacterial ZnOnp would provide a differential cell behavior and thereby a desirable biological response, facilitating the long term success of an implant.

Surface roughness mediated adhesion forces between borosilicate glass and gram-positive bacteria.

PubMed

Preedy, Emily; Perni, Stefano; Nipiĉ, Damijan; Bohinc, Klemen; Prokopovich, Polina

2014-08-12

It is well-known that a number of surface characteristics affect the extent of adhesion between two adjacent materials. One of such parameters is the surface roughness as surface asperities at the nanoscale level govern the overall adhesive forces. For example, the extent of bacterial adhesion is determined by the surface topography; also, once a bacteria colonizes a surface, proliferation of that species will take place and a biofilm may form, increasing the resistance of bacterial cells to removal. In this study, borosilicate glass was employed with varying surface roughness and coated with bovine serum albumin (BSA) in order to replicate the protein layer that covers orthopedic devices on implantation. As roughness is a scale-dependent process, relevant scan areas were analyzed using atomic force microscope (AFM) to determine Ra; furthermore, appropriate bacterial species were attached to the tip to measure the adhesion forces between cells and substrates. The bacterial species chosen (Staphylococci and Streptococci) are common pathogens associated with a number of implant related infections that are detrimental to the biomedical devices and patients. Correlation between adhesion forces and surface roughness (Ra) was generally better when the surface roughness was measured through scanned areas with size (2 × 2 μm) comparable to bacteria cells. Furthermore, the BSA coating altered the surface roughness without correlation with the initial values of such parameter; therefore, better correlations were found between adhesion forces and BSA-coated surfaces when actual surface roughness was used instead of the initial (nominal) values. It was also found that BSA induced a more hydrophilic and electron donor characteristic to the surfaces; in agreement with increasing adhesion forces of hydrophilic bacteria (as determined through microbial adhesion to solvents test) on BSA-coated substrates.

Bacterial recolonization of the skin and wound contamination during cardiac surgery: a randomized controlled trial of the use of plastic adhesive drape compared with bare skin.

PubMed

Falk-Brynhildsen, K; Söderquist, B; Friberg, O; Nilsson, U G

2013-06-01

Sternal wound infection after cardiac surgery is a serious complication. Various perioperative strategies, including plastic adhesive drapes, are used to reduce bacterial contamination of surgical wounds. To compare plastic adhesive drape to bare skin regarding bacterial growth in wound and time to recolonization of the adjacent skin intraoperatively, in cardiac surgery patients. This single-blinded randomized controlled trial (May 2010 to May 2011) included 140 patients scheduled for cardiac surgery via median sternotomy. The patients were randomly allocated to the adhesive drape (chest covered with plastic adhesive drape) or bare skin group. Bacterial samples were taken preoperatively and intraoperatively every hour during surgery until skin closure. Disinfection with 0.5% chlorhexidine solution in 70% alcohol decreased coagulase-negative staphylococci (CoNS), while the proportion colonized with Propionibacterium acnes was not significantly reduced and was still present in more than 50% of skin samples. P. acnes was significantly more common in men than in women. Progressive bacterial recolonization of the skin occurred within 2-3 h. At 120 min there were significantly more positive cultures in the adhesive drape group versus bare skin group for P. acnes (63% vs 44%; P = 0.034) and for CoNS (45% vs 24%; P = 0.013). The only statistically significant difference in bacterial growth in the surgical wound was higher proportion of CoNS at the end of surgery in the adhesive drape group (14.7% vs 4.4%; P = 0.044). Plastic adhesive drape does not reduce bacterial recolonization. P. acnes colonized men more frequently, and was not decreased by disinfection with chlorhexidine solution in alcohol. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Bacterial filamentation accelerates colonization of adhesive spots embedded in biopassive surfaces

NASA Astrophysics Data System (ADS)

Möller, Jens; Emge, Philippe; Avalos Vizcarra, Ima; Kollmannsberger, Philip; Vogel, Viola

2013-12-01

Sessile bacteria adhere to engineered surfaces and host tissues and pose a substantial clinical and economical risk when growing into biofilms. Most engineered and biological interfaces are of chemically heterogeneous nature and provide adhesive islands for bacterial attachment and growth. To mimic either defects in a surface coating of biomedical implants or heterogeneities within mucosal layers (Peyer's patches), we embedded micrometre-sized adhesive islands in a poly(ethylene glycol) biopassive background. We show experimentally and computationally that filamentation of Escherichia coli can significantly accelerate the bacterial surface colonization under physiological flow conditions. Filamentation can thus provide an advantage to a bacterial population to bridge non-adhesive distances exceeding 5 μm. Bacterial filamentation, caused by blocking of bacterial division, is common among bacterial species and can be triggered by environmental conditions or antibiotic treatment. While great awareness exists that the build-up of antibiotic resistance serves as intrinsic survival strategy, we show here that antibiotic treatment can actually promote surface colonization by triggering filamentation, which in turn prevents daughter cells from being washed away. Our combined microfabrication and computational approaches provide quantitative insights into mechanisms that enable biofouling of biopassive surfaces with embedded adhesive spots, even for spot distances that are multiples of the bacterial length.

Comparison of the Anti-Adhesion Activity of Three Different Cranberry Extracts on Uropathogenic P-fimbriated Escherichia coli: a Randomized, Double-blind, Placebo Controlled, Ex Vivo, Acute Study.

PubMed

Howell, Amy; Souza, Dan; Roller, Marc; Fromentin, Emilie

2015-07-01

Research suggests that cranberry (Vaccinium macrocarpon) helps maintain urinary tract health. Bacterial adhesion to the uroepithelium is the initial step in the progression to development of a urinary tract infection. The bacterial anti-adhesion activity of cranberry proanthocyanidins (PACs) has been demonstrated in vitro. Three different cranberry extracts were developed containing a standardized level of 36 mg of PACs. This randomized, double-blind, placebo controlled, ex vivo, acute study was designed to compare the anti-adhesion activity exhibited by human urine following consumption of three different cranberry extracts on uropathogenic P-fimbriated Escherichia coli in healthy men and women. All three cranberry extracts significantly increased anti-adhesion activity in urine. from 6 to 12 hours after intake of a single dose standardized to deliver 36 mg of PACs (as measured by the BL-DMAC method), versus placebo.

Comparison of the effect of resin infiltrant, fluoride varnish, and nano-hydroxy apatite paste on surface hardness and streptococcus mutans adhesion to artificial enamel lesions.

PubMed

Aziznezhad, Mahdiye; Alaghemand, Homayoon; Shahande, Zahra; Pasdar, Nilgoon; Bijani, Ali; Eslami, Abdolreza; Dastan, Zohre

2017-03-01

Dental caries is a major public health problem, and Streptococcus mutans is considered the main causal agent of dental caries. This study aimed to compare the effect of three re-mineralizing materials: resin infiltrant, fluoride varnish, and nano-hydroxy apatite paste on the surface hardness and adhesion of Streptococcus mutans as noninvasive treatments for initial enamel lesions. This experimental study was conducted from December 2015 through March 2016 in Babol, Iran. Artificial enamel lesions were created on 60 enamel surfaces, which were divided into two groups: Group A and Group B (30 subjects per group). Group A was divided into three subgroups (10 samples in each subgroup), including fluoride varnish group, nano-hydroxy apatite paste group (Nano P paste), and resin infiltrant group (Icon-resin). In Group A, the surface hardness of each sample was measured in three stages: First, on an intact enamel (baseline); second, after creating artificial enamel lesions; third, after application of re-mineralizing materials. In Group B, the samples were divided into five subgroups, including intact enamel, demineralized enamel, demineralized enamel treated with fluoride varnish, Nano P paste, and Icon-resin. In Group B, standard Streptococcus mutans bacteria adhesion (PTCC 1683) was examined and reported in terms of colony forming units (CFU/ml). Then, data were analyzed using ANOVA, Kruskal-Wallis, Mann-Whitney, and post hoc tests. In Group A, after treatment with re-mineralizing materials, the Icon-resin group had the highest surface hardness among the studied groups, then the Nano P paste group and fluoride varnish group, respectively (p = 0.035). In Group B, in terms of bacterial adhesion, fluoride varnish group had zero bacterial adhesion level, and then the Nano P paste group, Icon-resin group, intact enamel group, and the de-mineralized enamel group showed bacterial adhesion increasing in order (p < 0.001). According to the study among the examined materials, the resin infiltrant increased the tooth surface hardness as the intact enamel and fluoride varnish had the highest reduction level for bacterial adhesion. Nano P paste had an effect between the two materials, both in increasing surface hardness and reducing bacterial adhesion.

Non-invasive vibrational SFG spectroscopy reveals that bacterial adhesion can alter the conformation of grafted "brush" chains on SAM.

PubMed

Bulard, Emilie; Guo, Ziang; Zheng, Wanquan; Dubost, Henri; Fontaine-Aupart, Marie-Pierre; Bellon-Fontaine, Marie-Noëlle; Herry, Jean-Marie; Briandet, Romain; Bourguignon, Bernard

2011-04-19

Understanding bacterial adhesion on a surface is a crucial step to design new materials with improved properties or to control biofilm formation and eradication. Sum Frequency Generation (SFG) vibrational spectroscopy has been employed to study in situ the conformational response of a self-assembled monolayer (SAM) of octadecanethiol (ODT) on a gold film to the adhesion of hydrophilic and hydrophobic ovococcoid model bacteria. The present work highlights vibrational SFG spectroscopy as a powerful and unique non-invasive biophysical technique to probe and control bacteria interaction with ordered surfaces. Indeed, the SFG vibrational spectral changes reveal different ODT SAM conformations in air and upon exposure to aqueous solution or bacterial adhesion. Furthermore, this effect depends on the bacterial cell surface properties. The SFG spectral modeling demonstrates that hydrophobic bacteria flatten the ODT SAM alkyl chain terminal part, whereas the hydrophilic ones raise this ODT SAM terminal part. Microorganism-induced alteration of grafted chains can thus affect the desired interfacial functionality, a result that should be considered for the design of new reactive materials. © 2011 American Chemical Society

Adhesion to brown trout skin mucus, antagonism against cyst adhesion and pathogenicity to rainbow trout of some inhibitory bacteria against Saprolegnia parasitica .

PubMed

Carbajal-González, M T; Fregeneda-Grandes, J M; González-Palacios, C; Aller-Gancedo, J M

2013-04-29

Biological control of saprolegniosis with bacteria might be an alternative to the use of chemical compounds. Among criteria for the selection of such bacteria are their absence of pathogenicity to fish and their ability to prevent adhesion of the pathogen to the skin mucus. The pathogenicity to rainbow trout of 21 bacterial isolates with in vitro inhibitory activity against Saprolegnia parasitica was studied. Fifteen of the isolates, identified as Aeromonas sobria, Pantoea agglomerans, Pseudomonas fluorescens, Serratia fonticola, Xanthomonas retroflexus and Yersinia kristensenii, were non-pathogenic when injected into rainbow trout. Their capacity to adhere to the skin mucus of male and female brown trout and to reduce the adhesion of S. parasitica cysts under exclusion, competition and displacement conditions was tested. The 15 bacterial isolates showed a low adhesion rate, ranging between 1.7% (for an A. sobria isolate) and 15.3% (a P. fluorescens isolate). This adhesion was greater in the case of mucus from male brown trout than from females. Similarities in the adhesion to male mucus and other substrates and correlation to that observed to polystyrene suggest that adhesion to skin mucus does not depend on the substrate. A high percentage (88.9%) of the S. parasitica cysts adhered to the skin mucus of male brown trout. Almost all of the bacteria reduced this adhesion ratio significantly under exclusion and competition conditions. However, only half of the isolates displaced cysts from skin mucus, and more bacterial cells were necessary for this effect. A novel method to study the adhesion of S. parasitica cysts to skin mucus of trout and their interactions with inhibitory bacteria is described.

Influence of human milk oligosaccharides on adherence of bifidobacteria and clostridia to cell lines.

PubMed

Musilova, Sarka; Modrackova, Nikol; Doskocil, Ivo; Svejstil, Roman; Rada, Vojtech

2017-12-01

Adhesion of gut bacteria to the intestinal epithelium is the first step in their colonization of the neonatal immature gut. Bacterial colonization of the infant gut is influenced by several factors, of which the most important are the mode of delivery and breast-feeding. Breast-fed infants ingest several grams of human milk oligosaccharides (HMOs) per day, which can become receptor decoys for intestinal bacteria. The most abundant intestinal bacteria in vaginally delivered infants are bifidobacteria, whereas infants born by cesarean section are colonized by clostridia. The influence of HMOs on the adhesion of five strains of intestinal bacteria (three bifidobacterial strains and two clostridial strains) to mucus-secreting and non-mucus-secreting human epithelial cells was investigated. Bifidobacterium bifidum 1 and Bifidobacterium longum displayed almost the same level of adhesion in the presence and absence of HMOs. By contrast, adhesion of Clostridium butyricum 1 and 2 decreased from 14.41% to 6.72% and from 41.54% to 30.91%, respectively, in the presence of HMOs. The results of this study indicate that HMOs affect bacterial adhesion and are an important factor influencing bacterial colonization of the gut. Adhesion of the tested bacteria correlates with their ability to autoaggregate.

Adhesion of Asaia bogorensis to Glass and Polystyrene in the Presence of Cranberry Juice.

PubMed

Antolak, Hubert; Kregiel, Dorota; Czyzowska, Agata

2015-06-01

The aim of the study was to evaluate the adhesion abilities of the acetic acid bacterium Asaia bogorensis to glass and polystyrene in the presence of American cranberry (Vaccinium macrocarpon) juice. The strain of A. bogorensis used was isolated from spoiled commercial fruit-flavored drinking water. The cranberry juice was analyzed for polyphenols, organic acids, and carbohydrates using high-performance liquid chromatography and liquid chromatography-mass spectrometry techniques. The adhesive abilities of bacterial cells in culture medium supplemented with cranberry juice were determined using luminometry and microscopy. The viability of adhered and planktonic bacterial cells was determined by the plate count method, and the relative adhesion coefficient was calculated. This strain of A. bogorensis was characterized by strong adhesion properties that were dependent upon the type of surface. The highest level of cell adhesion was found on the polystyrene. However, in the presence of 10% cranberry juice, attachment of bacterial cells was three times lower. Chemical analysis of juice revealed the presence of sugars, organic acids, and anthocyanins, which were identified as galactosides, glucosides, and arabinosides of cyanidin and peonidin. A-type proanthocyanidins responsible for the antiadhesion properties of V. macrocarpon also were detected.

Phenotypic Heterogeneity in Attachment of Marine Bacteria toward Antifouling Copolymers Unraveled by AFM.

PubMed

El-Kirat-Chatel, Sofiane; Puymege, Aurore; Duong, The H; Van Overtvelt, Perrine; Bressy, Christine; Belec, Lénaïk; Dufrêne, Yves F; Molmeret, Maëlle

2017-01-01

Up to recent years, bacterial adhesion has mostly been evaluated at the population level. Single cell level has improved in the past few years allowing a better comprehension of the implication of individual behaviors as compared to the one of a whole community. A new approach using atomic force microscopy (AFM) to measure adhesion forces between a live bacterium attached via a silica microbead to the AFM tipless cantilever and the surface has been recently developed. The objectives of this study is to examine the bacterial adhesion to a surface dedicated to ship hulls at the population and the cellular level to understand to what extent these two levels could be correlated. Adhesion of marine bacteria on inert surfaces are poorly studied in particular when substrata are dedicated to ship hulls. Studying these interactions in this context are worthwhile as they may involve different adhesion behaviors, taking place in salty conditions, using different surfaces than the ones usually utilized in the literacy. FRC (fouling release coatings)-SPC (self-polishing coatings) hybrids antifouling coatings have been used as substrata and are of particular interest for designing environmentally friendly surfaces, combining progressive surface erosion and low adhesion properties. In this study, a hybrid coating has been synthetized and used to study the adhesion of three marine bacteria, displaying different surface characteristics, using microplate assays associated with confocal scanning laser microscopy (CSLM) and AFM. This study shows that the bacterial strain that appeared to have the weakest adhesion and biofilm formation abilities when evaluated at the population level using microplates assays and CSLM, displayed stronger adhesion forces on the same surfaces at the single cell level using AFM. In addition, one of the strains tested which presented a strong ability to adhere and to form biofilm at the population level, displayed a heterogeneous phenotypic behavior at the single cell level. Therefore, these results suggest that the evaluation of adhesion at the population level cannot always be correlated with adhesion forces measured individually by AFM and that some bacteria are prone to phenotypic heterogeneity among their population.

Bacterial adhesion forces to Ag-impregnated contact lens cases and transmission to contact lenses.

PubMed

Qu, Wenwen; Busscher, Henk J; van der Mei, Henny C; Hooymans, Johanna M M

2013-03-01

To measure adhesion forces of Pseudomonas aeruginosa, Staphylococcus aureus, and Serratia marcescens to a rigid contact lens (CL), standard polypropylene, and Ag-impregnated lens cases using atomic force microscopy and determine bacterial transmission from lens case to CL. Adhesion forces of bacterial strains to Ag-impregnated and polypropylene lens cases and a rigid CL were measured using atomic force microscopy. Adhesion forces were used to calculate Weibull distributions, from which transmission probabilities from lens case to CL were derived. Transmission probabilities were compared with actual transmission of viable bacteria from a lens case to the CL in 0.9% NaCl and in an antimicrobial lens care solution. Bacterial transmission probabilities from polypropylene lens cases based on force analysis coincided well for all strains with actual transmission in 0.9% NaCl. Bacterial adhesion forces on Ag-impregnated lens cases were much smaller than that on polypropylene and CLs, yielding a high probability of transmission. Comparison with actual bacterial transmission indicated bacterial killing due to Ag ions during colony-forming unit transmission from an Ag-impregnated lens case, especially for P. aeruginosa. Transmission of viable bacteria from Ag-impregnated lens cases could be further decreased by use of an antimicrobial lens care solution instead of 0.9% NaCl. Bacterial transmission probabilities are higher from Ag-impregnated lens cases than from polypropylene lens cases because of small adhesion forces, but this is compensated for by enhanced bacterial killing due to Ag impregnation, especially when in combination with an antimicrobial lens care solution. This calls for a balanced combination of antimicrobial lens care solutions and surface properties of a lens case and CL.

Methodologies for screening of bacteria-carbohydrate interactions: anti-adhesive milk oligosaccharides as a case study.

PubMed

Lane, Jonathan A; Mariño, Karina; Rudd, Pauline M; Carrington, Stephen D; Slattery, Helen; Hickey, Rita M

2012-07-01

Many studies have demonstrated the capacity of glycan-based compounds to disrupt microbial binding to mucosal epithelia. Therefore, oligosaccharides have potential application in the prevention of certain bacterial diseases. However, current screening methods for the identification of anti-adhesive oligosaccharides have limitations: they are time-consuming and require large amounts of oligosaccharides. There is a need to develop analytical techniques which can quickly screen for, and structurally define, anti-adhesive oligosaccharides prior to using human cell line models of infection. Considering this, we have developed a rapid method for screening complex oligosaccharide mixtures for potential anti-adhesive activity against bacteria. Our approach involves the use of whole bacterial cells to "deplete" free oligosaccharides from solution. As a case study, the free oligosaccharides from the colostrum of Holstein Friesian cows were screened for interactions with whole Escherichia coli cells. Reductions in oligosaccharide concentrations were determined by High pH Anion Exchange Chromatography and Hydrophilic Interaction Liquid Chromatography (HILIC-HPLC). Oligosaccharide structures were confirmed by a combination of HILIC-HPLC, exoglycosidase digestion and off-line negative ion mode MS/MS. The depletion assay confirmed selective bacterial interaction with certain bovine oligosaccharides which in previous studies, by other methodologies, had been shown to interact with E. coli. In particular, the bacterial cells depleted the following oligosaccharides in a population dependent manner: 3'-sialyllactose, disialyllactose, and 6'-sialyllactosamine. The assay methodology was further validated by studies in which we demonstrated the inhibitory activity of 3'-sialyllactose, and a mixture of bovine colostrum oligosaccharides, on E. coli adhesion to differentiated HT-29 cells. Copyright © 2012 Elsevier B.V. All rights reserved.

An investigation of the effect of scaling-induced surface roughness on bacterial adhesion in common fixed dental restorative materials.

PubMed

Checketts, Matthew R; Turkyilmaz, Ilser; Asar, Neset Volkan

2014-11-01

Bacterial plaque must be routinely removed from teeth, adjacent structures, and prostheses. However, the removal of this plaque can inadvertently increase the risk of future bacterial adhesion. The purpose of this investigation was to assess the change in the surface roughness of 3 different surfaces after dental prophylactic instrumentation and how this influenced bacterial adhesion. Forty specimens each of Type III gold alloy, lithium disilicate, and zirconia were fabricated in the same dimensions. The specimens were divided into 4 groups: ultrasonic scaler, stainless steel curette, prophylaxis cup, and control. Pretreatment surface roughness measurements were made with a profilometer. Surface treatments in each group were performed with a custom mechanical scaler. Posttreatment surface roughness values were measured. In turn, the specimens were inoculated with Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces viscosus. Bacterial adhesion was assessed by rinsing the specimens with sterile saline to remove unattached cells. The specimens were then placed in sterile tubes with 1 mL of sterile saline. The solution was plated and quantified. Scanning electron microscopy was performed. The statistical analysis of surface roughness was completed by using repeated-measures single-factor ANOVA with a Bonferroni correction. The surface roughness values for gold alloy specimens increased as a result of prophylaxis cup treatment (0.221 to 0.346 Ra) (P<.01) and stainless steel curette treatment (0.264 to 1.835 Ra) (P<.01). The results for bacterial adhesion to gold alloy proved inconclusive. A quantitative comparison indicated no statistically significant differences in pretreatment and posttreatment surface roughness values for lithium disilicate and zirconia specimens. In spite of these similarities, the overall bacterial adherence values for lithium disilicate were significantly greater than those recorded for gold alloy or zirconia (P<.05). Instrumentation of the lithium disilicate and zirconia with the stainless steel curette significantly increased bacterial adhesion compared with the control (P<.05). The results of this investigation indicate that Type III gold alloy exhibited increased surface roughness values after stainless steel curette and prophylaxis cup treatments. Zirconia was less susceptible to bacterial adhesion than lithium disilicate, and greater bacterial adhesion was found for the stainless steel curette than the other instrumentation methods. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Initial Bacterial Adhesion on Different Yttria-Stabilized Tetragonal Zirconia Implant Surfaces in Vitro

PubMed Central

Karygianni, Lamprini; Jähnig, Andrea; Schienle, Stefanie; Bernsmann, Falk; Adolfsson, Erik; Kohal, Ralf J.; Chevalier, Jérôme; Hellwig, Elmar; Al-Ahmad, Ali

2013-01-01

Bacterial adhesion to implant biomaterials constitutes a virulence factor leading to biofilm formation, infection and treatment failure. The aim of this study was to examine the initial bacterial adhesion on different implant materials in vitro. Four implant biomaterials were incubated with Enterococcus faecalis, Staphylococcus aureus and Candida albicans for 2 h: 3 mol % yttria-stabilized tetragonal zirconia polycrystal surface (B1a), B1a with zirconium oxide (ZrO2) coating (B2a), B1a with zirconia-based composite coating (B1b) and B1a with zirconia-based composite and ZrO2 coatings (B2b). Bovine enamel slabs (BES) served as control. The adherent microorganisms were quantified and visualized using scanning electron microscopy (SEM); DAPI and live/dead staining. The lowest bacterial count of E. faecalis was detected on BES and the highest on B1a. The fewest vital C. albicans strains (42.22%) were detected on B2a surfaces, while most E. faecalis and S. aureus strains (approximately 80%) were vital overall. Compared to BES; coated and uncoated zirconia substrata exhibited no anti-adhesive properties. Further improvement of the material surface characteristics is essential. PMID:28788415

Initial Bacterial Adhesion on Different Yttria-Stabilized Tetragonal Zirconia Implant Surfaces in Vitro.

PubMed

Karygianni, Lamprini; Jähnig, Andrea; Schienle, Stefanie; Bernsmann, Falk; Adolfsson, Erik; Kohal, Ralf J; Chevalier, Jérôme; Hellwig, Elmar; Al-Ahmad, Ali

2013-12-04

Bacterial adhesion to implant biomaterials constitutes a virulence factor leading to biofilm formation, infection and treatment failure. The aim of this study was to examine the initial bacterial adhesion on different implant materials in vitro . Four implant biomaterials were incubated with Enterococcus faecalis , Staphylococcus aureus and Candida albicans for 2 h: 3 mol % yttria-stabilized tetragonal zirconia polycrystal surface (B1a), B1a with zirconium oxide (ZrO₂) coating (B2a), B1a with zirconia-based composite coating (B1b) and B1a with zirconia-based composite and ZrO₂ coatings (B2b). Bovine enamel slabs (BES) served as control. The adherent microorganisms were quantified and visualized using scanning electron microscopy (SEM); DAPI and live/dead staining. The lowest bacterial count of E. faecalis was detected on BES and the highest on B1a. The fewest vital C. albicans strains (42.22%) were detected on B2a surfaces, while most E. faecalis and S. aureus strains (approximately 80%) were vital overall. Compared to BES; coated and uncoated zirconia substrata exhibited no anti-adhesive properties. Further improvement of the material surface characteristics is essential.

Bacterial adhesion to protein-coated surfaces: An AFM and QCM-D study

NASA Astrophysics Data System (ADS)

Strauss, Joshua; Liu, Yatao; Camesano, Terri A.

2009-09-01

Bacterial adhesion to biomaterials, mineral surfaces, or other industrial surfaces is strongly controlled by the way bacteria interact with protein layers or organic matter and other biomolecules that coat the materials. Despite this knowledge, many studies of bacterial adhesion are performed under clean conditions, instead of in the presence of proteins or organic molecules. We chose fetal bovine serum (FBS) as a model protein, and prepared FBS films on quartz crystals. The thickness of the FBS layer was characterized using atomic force microscopy (AFM) imaging under liquid and quartz crystal microbalance with dissipation (QCM-D). Next, we characterized how the model biomaterial surface would interact with the nocosomial pathogen Staphylococcus epidermidis. An AFM probe was coated with S. epidermidis cells and used to probe a gold slide that had been coated with FBS or another protein, fibronectin (FN). These experiments show that AFM and QCM-D can be used in complementary ways to study the complex interactions between bacteria, proteins, and surfaces.

Vizantin inhibits bacterial adhesion without affecting bacterial growth and causes Streptococcus mutans biofilm to detach by altering its internal architecture.

PubMed

Takenaka, Shoji; Oda, Masataka; Domon, Hisanori; Ohsumi, Tatsuya; Suzuki, Yuki; Ohshima, Hayato; Yamamoto, Hirofumi; Terao, Yutaka; Noiri, Yuichiro

2016-11-11

An ideal antibiofilm strategy is to control both in the quality and quantity of biofilm while maintaining the benefits derived from resident microflora. Vizantin, a recently developed immunostimulating compound, has also been found to have antibiofilm property. This study evaluated the influence on biofilm formation of Streptococcus mutans in the presence of sulfated vizantin and biofilm development following bacterial adhesion on a hydroxyapatite disc coated with sulfated vizantin. Supplementation with sulfated vizantin up to 50 μM did not affect either bacterial growth or biofilm formation, whereas 50 μM sulfated vizantin caused the biofilm to readily detach from the surface. Sulfated vizantin at the concentration of 50 μM upregulated the expression of the gtfB and gtfC genes, but downregulated the expression of the gtfD gene, suggesting altered architecture in the biofilm. Biofilm development on the surface coated with sulfated vizantin was inhibited depending on the concentration, suggesting prevention from bacterial adhesion. Among eight genes related to bacterial adherence in S. mutans, expression of gtfB and gtfC was significantly upregulated, whereas the expression of gtfD, GbpA and GbpC was downregulated according to the concentration of vizantin, especially with 50 μM vizantin by 0.8-, 0.4-, and 0.4-fold, respectively. These findings suggest that sulfated vizantin may cause structural degradation as a result of changing gene regulation related to bacterial adhesion and glucan production of S. mutans. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparative evaluation of aggressiveness traits in staphylococcal strains from severe infections versus nasopharyngeal carriage.

PubMed

Săndulescu, Oana; Bleotu, Coralia; Matei, Lilia; Streinu-Cercel, Anca; Oprea, Mihaela; Drăgulescu, Elena Carmina; Chifiriuc, Mariana Carmen; Rafila, Alexandru; Pirici, Daniel; Tălăpan, Daniela; Dorobăţ, Olga Mihaela; Neguţ, Alina Cristina; Oţelea, Dan; Berciu, Ioana; Ion, Daniela Adriana; Codiţă, Irina; Calistru, Petre Iacob; Streinu-Cercel, Adrian

2017-01-01

Despite their commensal status, staphylococci can become problematic pathogens expressing multiple and redundant virulence factors. This study aimed to evaluate aggressiveness markers comparatively in staphylococcal strains isolated from severe infections versus asymptomatic carriage in order to identify clinically relevant bacterial traits that could easily be detected in clinical practice and could be suggestive for particular host-pathogen interactions such as cyto-adhesion or biofilm formation, ultimately orienting the clinical decision-making process. We have used in vitro phenotypic methods to assess adhesion to and invasion of eukaryotic cells, biofilm development, and expression of soluble virulence factors in 92 Staphylococcus spp. strains. The adhesion index, invasion capacity, biofilm formation and expression of soluble factors did not differ significantly between clinical and commensal strains. The major bacterial traits we found to be significantly more prevalent in clinical staphylococci were the aggregative adhesion pattern (P = 0.012), cluster adhesion (P = 0.001) and tetrad morphology (P = 0.018). The aggregative adhesion pattern was correlated with higher cyto-adhesion (P < 0.001), higher invasion capacity (P = 0.003) and lower Carmeli scores (P = 0.002). Three major bacterial traits, namely tetrad morphology, aggregative adhesion pattern, and resistance to methicillin (acronym: TAM), can be used to compute an aggressiveness score (SAS) predictive of the staphylococcal strain's virulence and capacity to initiate and develop a biofilm-driven chronic infectious process versus a fulminant acute infection, in a susceptible host. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nitrogen starvation affects bacterial adhesion to soil

PubMed Central

Borges, Maria Tereza; Nascimento, Antônio Galvão; Rocha, Ulisses Nunes; Tótola, Marcos Rogério

2008-01-01

One of the main factors limiting the bioremediation of subsoil environments based on bioaugmentation is the transport of selected microorganisms to the contaminated zones. The characterization of the physiological responses of the inoculated microorganisms to starvation, especially the evaluation of characteristics that affect the adhesion of the cells to soil particles, is fundamental to anticipate the success or failure of bioaugmentation. The objective of this study was to investigate the effect of nitrogen starvation on cell surface hydrophobicity and cell adhesion to soil particles by bacterial strains previously characterized as able to use benzene, toluene or xilenes as carbon and energy sources. The strains LBBMA 18-T (non-identified), Arthrobacter aurescens LBBMA 98, Arthrobacter oxydans LBBMA 201, and Klebsiella sp. LBBMA 204–1 were used in the experiments. Cultivation of the cells in nitrogen-deficient medium caused a significant reduction of the adhesion to soil particles by all the four strains. Nitrogen starvation also reduced significantly the strength of cell adhesion to the soil particles, except for Klebsiella sp. LBBMA 204–1. Two of the four strains showed significant reduction in cell surface hydrophobicity. It is inferred that the efficiency of bacterial transport through soils might be potentially increased by nitrogen starvation. PMID:24031246

Insights into the relation between adhesion force and chalcopyrite-bioleaching by Acidithiobacillus ferrooxidans.

PubMed

Zhu, Jianyu; Wang, Qianfen; Zhou, Shuang; Li, Qian; Gan, Min; Jiang, Hao; Qin, Wenqing; Liu, Xueduan; Hu, Yuehua; Qiu, Guanzhou

2015-02-01

This paper presents a study on the relation between bacterial adhesion force and bioleaching rate of chalcopyrite, which sheds light on the influence of interfacial interaction on bioleaching behavior. In our research, Acidithiobacillus ferrooxidans (A. ferrooxidans) were adapted to grow with FeSO4 · 7H2O, element sulfur or chalcopyrite. Then, surface properties of Acidithiobacillus ferrooxidans and chalcopyrite were analyzed by contact angle, zeta potential and Fourier transform infrared spectroscopy (FTIR). Adhesion force between bacteria and chalcopyrite was measured by atomic force microscopy (AFM). Attachment and bioleaching behaviors were also monitored. The results showed that A. ferrooxidans adapted with chalcopyrite exhibited the strongest adhesion force to chalcopyrite and the highest bioleaching rate. Culture adapted with sulfur bacteria took second place and FeSO4 · 7H2O-adapted bacteria were the lowest. Bioleaching rate and bacterial attachment capacity were positively related to bacterial adhesion force, which is affected by the nature of energy source. According to this work, the attachment of bacteria to chalcopyrite surface is one of the most important aspects that influence the bioleaching process of chalcopyrite. Copyright © 2014 Elsevier B.V. All rights reserved.

Zinc-ion implanted and deposited titanium surfaces reduce adhesion of Streptococccus mutans

NASA Astrophysics Data System (ADS)

Xu, Juan; Ding, Gang; Li, Jinlu; Yang, Shenhui; Fang, Bisong; Sun, Hongchen; Zhou, Yanmin

2010-10-01

While titanium (Ti) is a commonly used dental implant material with advantageous biocompatible and mechanical properties, native Ti surfaces do not have the ability to prevent bacterial colonization. The objective of this study was to evaluate the chemical composition and bacterial adhesive properties of zinc (Zn) ion implanted and deposited Ti surfaces (Zn-PIIID-Ti) as potential dental implant materials. Surfaces of pure Ti (cp-Ti) were modified with increasing concentrations of Zn using plasma immersion ion implantation and deposition (PIIID), and elemental surface compositions were characterized by X-ray photoelectron spectrometry (XPS). To evaluate bacterial responses, Streptococcus mutans were seeded onto the modifiedTi surfaces for 48 h and subsequently observed by scanning electron microscopy. Relative numbers of bacteria on each surface were assessed by collecting the adhered bacteria, reculturing and counting colony forming units after 48 h on bacterial grade plates. Ti, oxygen and carbon elements were detected on all surfaces by XPS. Increased Zn signals were detected on Zn-PIIID-Ti surfaces, correlating with an increase of Zn-deposition time. Substantial numbers of S. mutans adhered to cp-Ti samples, whereas bacterial adhesion on Zn-PIIID-Ti surfaces signficantly decreased as the Zn concentration increased ( p < 0.01). In conclusion, PIIID can successfully introduce Zn onto a Ti surface, forming a modified surface layer bearing Zn ions that consequently deter adhesion of S. mutans, a common bacterium in the oral environment.

Structure, Function, and Assembly of Type 1 Fimbriae

NASA Astrophysics Data System (ADS)

Knight, Stefan D.; Bouckaert, Julie

Bacterial infections constitute a major global health problem, acutely accentuated by the rapid spread of antibiotic resistant bacterial strains. The widespread need for bacteria to attach - adhere - to target cells before they can initiate an infection may be used to advantage by targeting the bacterial adhesion tools such as pili and fimbriae for development of novel anti-bacterial vaccines and drugs. Type 1 fimbriae are widely expressed by Escherichia coli. and are used by uropathogenic strains to mediate attachment to specific niches in the urinary tract. These fimbriae belong to a class of fibrillar adhesion organelles assembled through the chaperone/usher pathway, one of the terminal branches of the general secretion pathway in Gram-negative bacteria. Our understanding of the assembly, structure and function of these structures has evolved significantly over the last decade. Here, we summarize current understanding of the function and biogenesis of fibrillar adhesion organelles, and provide some examples of recent progress towards interfering with bacterial adhesion as a means to prevent infection.

Development of functional biointerfaces by surface modification of polydimethylsiloxane with bioactive chlorogenic acid.

PubMed

Wu, Ming; He, Jia; Ren, Xiao; Cai, Wen-Sheng; Fang, Yong-Chun; Feng, Xi-Zeng

2014-04-01

The effect of physicochemical surface properties and chemical structure on the attachment and viability of bacteria and mammalian cells has been extensively studied for the development of biologically relevant applications. In this study, we report a new approach that uses chlorogenic acid (CA) to modify the surface wettability, anti-bacterial activity and cell adhesion properties of polydimethylsiloxane (PDMS). The chemical structure of the surface was obtained by X-ray photoelectron spectroscopy (XPS), the roughness was measured by atomic force microscopy (AFM), and the water contact angle was evaluated for PDMS substrates both before and after CA modification. Molecular modelling showed that the modification was predominately driven by van der Waals and electrostatic interactions. The exposed quinic-acid moiety improved the hydrophilicity of CA-modified PDMS substrates. The adhesion and viability of E. coli and HeLa cells were investigated using fluorescence and phase contrast microscopy. Few viable bacterial cells were found on CA-coated PDMS surfaces compared with unmodified PDMS surfaces. Moreover, HeLa cells exhibited enhanced adhesion and increased spreading on the modified PDMS surface. Thus, CA-coated PDMS surfaces reduced the ratio of viable bacterial cells and increased the adhesion of HeLa cells. These results contribute to the purposeful design of anti-bacterial surfaces for medical device use. Copyright © 2013 Elsevier B.V. All rights reserved.

In vitro assessments on bacterial adhesion and corrosion performance of TiN coating on Ti6Al4V titanium alloy synthesized by multi-arc ion plating

NASA Astrophysics Data System (ADS)

Lin, Naiming; Huang, Xiaobo; Zhang, Xiangyu; Fan, Ailan; Qin, Lin; Tang, Bin

2012-07-01

TiN coating was synthesized on Ti6Al4V titanium alloy surface by multi-arc ion plating (MIP) technique. Surface morphology, cross sectional microstructure, elemental distributions and phase compositions of the obtained coating were analyzed by means of scanning electron microscope (SEM), optical microscope (OM), glow discharge optical emission spectroscope (GDOES) and X-ray diffraction (XRD). Bacterial adhesion and corrosion performance of Ti6Al4V and the TiN coating were assessed via in vitro bacterial adhesion tests and corrosion experiments, respectively. The results indicated that continuous and compact coating which was built up by pure TiN with a typical columnar crystal structure has reached a thickness of 1.5 μm. This TiN coating could significantly reduce the bacterial adhesion and enhance the corrosion resistance of Ti6Al4V substrate.

Bisphosphonates enhance bacterial adhesion and biofilm formation on bone hydroxyapatite.

PubMed

Kos, Marcin; Junka, Adam; Smutnicka, Danuta; Szymczyk, Patrycja; Gluza, Karolina; Bartoszewicz, Marzenna

2015-07-01

Because of the suspicion that bisphosphonates enhance bacterial colonization, this study evaluated adhesion and biofilm formation by Streptococcus mutans 25175, Staphylococcus aureus 6538, and Pseudomonas aeruginosa 14454 reference strains on hydroxyapatite coated with clodronate, pamidronate, or zoledronate. Bacterial strains were cultured on bisphosphonate-coated and noncoated hydroxyapatite discs. After incubation, nonadhered bacteria were removed by centrifugation. Biofilm formation was confirmed by scanning electron microscopy. Bacterial colonization was estimated using quantitative cultures compared by means with Kruskal-Wallis and post-hoc Student-Newman-Keuls tests. Modeling of the interactions between bisphosphonates and hydroxyapatite was performed using the Density Functional Theory method. Bacterial colonization of the hydroxyapatite discs was significantly higher for all tested strains in the presence of bisphosphonates vs. Adherence in the presence of pamidronate was higher than with other bisphosphonates. Density Functional Theory analysis showed that the protonated amine group of pamidronate, which are not present in clodronate or zoledronate, forms two additional hydrogen bonds with hydroxyapatite. Moreover, the reactive cationic amino group of pamidronate may attract bacteria by direct electrostatic interaction. Increased bacterial adhesion and biofilm formation can promote osteomyelitis, cause failure of dental implants or bisphosphonate-coated joint prostheses, and complicate bone surgery in patients on bisphosphonates. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

An in vitro assessment of titanium functionalized with polysaccharides conjugated with vascular endothelial growth factor for enhanced osseointegration and inhibition of bacterial adhesion.

PubMed

Hu, Xuefeng; Neoh, Koon-Gee; Shi, Zhilong; Kang, En-Tang; Poh, Chyekhoon; Wang, Wilson

2010-12-01

The long-term success of orthopedic implants may be compromised by defective osseointegration and bacterial infection. An effective approach to minimize implant failure would be to modify the surface of the implant to make it habitable for bone-forming cells and anti-infective at the same time. In this in vitro study, the surfaces of titanium (Ti) substrates were functionalized by first covalently grafting either dopamine followed by carboxymethyl chitosan (CMCS) or hyaluronic acid-catechol (HAC). Vascular endothelial growth factor (VEGF) was then conjugated to the polysaccharide-grafted surface. Antibacterial assay with Staphylococcus aureus (S. aureus) showed that the polysaccharide-modified substrates significantly decrease bacterial adhesion. The CMCS-functionalized Ti demonstrated better antibacterial property than the HAC-functionalized Ti since CMCS is bactericidal while HA only inhibits the adhesion of bacteria without killing them. Osteoblast attachment, as well as alkaline phosphatase (ALP) activity and calcium deposition were enhanced by the immobilized VEGF on the polysaccharide-grafted Ti. Thus, Ti substrates modified with polysaccharides conjugated with VEGF can promote osteoblast functions and concurrently reduce bacterial adhesion. Since VEGF is also known to enhance angiogenesis, the VEGF-polysaccharide functionalized substrates will have promising applications in the orthopedic field. Copyright © 2010 Elsevier Ltd. All rights reserved.

Identification and characterization of three Vibrio alginolyticus non-coding RNAs involved in adhesion, chemotaxis, and motility processes.

PubMed

Huang, Lixing; Hu, Jiao; Su, Yongquan; Qin, Yingxue; Kong, Wendi; Ma, Ying; Xu, Xiaojin; Lin, Mao; Yan, Qingpi

2015-01-01

The capability of Vibrio alginolyticus to adhere to fish mucus is a key virulence factor of the bacteria. Our previous research showed that stress conditions, such as Cu(2+), Pb(2+), Hg(2+), and low pH, can reduce this adhesion ability. Non-coding (nc) RNAs play a crucial role in regulating bacterial gene expression, affecting the bacteria's pathogenicity. To investigate the mechanism(s) underlying the decline in adhesion ability caused by stressors, we combined high-throughput sequencing with computational techniques to detect stressed ncRNA dynamics. These approaches yielded three commonly altered ncRNAs that are predicted to regulate the bacterial chemotaxis pathway, which plays a key role in the adhesion process of bacteria. We hypothesized they play a key role in the adhesion process of V. alginolyticus. In this study, we validated the effects of these three ncRNAs on their predicted target genes and their role in the V. alginolyticus adhesion process with RNA interference (i), quantitative real-time polymerase chain reaction (qPCR), northern blot, capillary assay, and in vitro adhesion assays. The expression of these ncRNAs and their predicted target genes were confirmed by qPCR and northern blot, which reinforced the reliability of the sequencing data and the target prediction. Overexpression of these ncRNAs was capable of reducing the chemotactic and adhesion ability of V. alginolyticus, and the expression levels of their target genes were also significantly reduced. Our results indicated that these three ncRNAs: (1) are able to regulate the bacterial chemotaxis pathway, and (2) play a key role in the adhesion process of V. alginolyticus.

No lower bacterial adhesion for ceramics compared to other biomaterials: An in vitro analysis.

PubMed

Slullitel, P A; Buttaro, M A; Greco, G; Oñativia, J I; Sánchez, M L; Mc Loughlin, S; García-Ávila, C; Comba, F; Zanotti, G; Piccaluga, F

2018-06-01

Although there is some clinical evidence of ceramic bearings being associated with a lower infection rate after total hip arthroplasty (THA), available data remains controversial since this surface is usually reserved for young, healthy patients. Therefore, we investigated the influence of five commonly used biomaterials on the adhesion potential of four biofilm-producing bacteria usually detected in infected THAs. Ceramic biomaterials exhibit less bacterial adherence than other biomaterials. In this in vitro research, we evaluated the ability of Staphylococcus aureus, Staphylococcus epidermidis ATCC 35984, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa to adhere to the surface of a cobalt-chromium metal head, a fourth-generation ceramic head, a fourth-generation ceramic insert, a highly-crossed linked polyethylene insert and a titanium porous-coated acetabular component. After an initial washing step, bacterial separation from the surface of each specimen was done with a vortex agitator. The colony-forming units were counted to determine the number of viable adherent bacteria. We found no differences on global bacterial adhesion between the different surfaces (p=0.5). E. coli presented the least adherence potential among the analysed pathogens (p<0.001). The combination of E. coli and S. epidermidis generated an antagonist effect over the adherence potential of S. epidermidis individually (58±4% vs. 48±5%; p=0.007). The combination of P. aeruginosa and S. aureus presented a trend to an increased adherence of P. aeruginosa independently, suggesting an agonist effect (71% vs. 62%; p=0.07). Ceramic bearings appeared not to be related to a lower bacterial adhesion than other biomaterials. However, different adhesive potentials among bacteria may play a major role on infection's inception. IV, in vitro study. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

The role of type III secretion system and lens material on adhesion of Pseudomonas aeruginosa to contact lenses.

PubMed

Shen, Elizabeth P; Tsay, Ruey-Yug; Chia, Jean-San; Wu, Semon; Lee, Jing-Wen; Hu, Fung-Rong

2012-09-21

To determine the distribution of invasive and cytotoxic genotypes among ocular isolates of P. aeruginosa and investigate the influence of the type III secretion system (T3SS) on adhesion to conventional, cosmetic, and silicone hydrogel contact lenses (CL). Clinical isolates from 2001 to 2010 were analyzed by multiplex PCR for exoS, exoU, and exoT genes. Bacterial adhesion to etafilcon, nelfilcon (gray colored), balafilcon, and galyfilcon CL with or without artificial tear fluid (ATF) incubation were compared. Surface characteristics were determined with scanning electron microscopy (SEM). Among 87 total isolates, 64 strains were from microbial keratitis cases. CL-related microbial keratitis (CLMK) isolates were mostly of the cytotoxic genotype (expressing exoU) (P = 0.002). No significant differences were found in bacterial adhesion to all types of CL between the genotypes under T3SS-inducing conditions. A trend for least bacterial adhesion of galyfilcon compared to the other CL was noted for both genotypes. Needle complex pscC mutants adhered less to all materials than the wild type (P < 0.05), indicating a role of the T3SS in contact lens adhesion. ATF-incubated CL had significantly more bacterial adhesion (P < 0.05). SEM showed most of the bacteria adhering on CL surfaces. CLMK isolates were mostly of cytotoxic genotype. Different genotypes did not significantly differ in its adhesion to various CL. T3SS and other adhesins are involved in bacteria-contact lens adhesion through complex interactions. Contact lens materials may also play an important role in the adherence of both genotypes of P. aeruginosa.

Surface nanoporosity has a greater influence on osteogenic and bacterial cell adhesion than crystallinity and wettability

NASA Astrophysics Data System (ADS)

Rodriguez-Contreras, Alejandra; Guadarrama Bello, Dainelys; Nanci, Antonio

2018-07-01

There has been much emphasis on the influence of crystallinity and wettability for modulating cell activity, particularly for bone biomaterials. In this context, we have generated titanium oxide layers with similar mesoporous topography and surface roughness but with amorphous or crystalline oxide layers and differential wettability. We then investigated their influence on the behavior of MC3T3 osteoblastic and bacterial cells. There was no difference in cell adhesion, spreading and growth on amorphous and crystalline surfaces. The number of focal adhesions was similar, however, cells on the amorphous surface exhibited a higher frequency of mature adhesions. The crystallinity of the surface layers also had no bearing on bacterial adhesion. While it cannot be excluded that surface crystallinity, roughness and wettability contribute to some degree to determining cell behavior, our data suggest that physical characteristics of surfaces represent the major determinant.

Adsorption of phenanthrene on activated carbon increases mineralization rate by specific bacteria.

PubMed

Leglize, Pierre; Alain, Saada; Jacques, Berthelin; Corinne, Leyval

2008-03-01

Bioavailability of polycyclic aromatic hydrocarbons (PAH) in soil is affected by PAH sorption to solid phase. We studied the influence of activated carbon (AC) on phenanthrene (PHE) mineralization by five degrading bacterial strains isolated from contaminated soil. PHE adsorption on AC was important and reduced PHE aqueous concentration up to 90%. PHE degradation was improved in the presence of activated carbon with three of the bacterial strains, named NAH1, MATE3 and MATE7, which produced biofilms, whereas it was not improved with the two other ones, which did not produce biofilms, MATE10 and MATE12. Monitoring PHE distribution during incubation showed that aqueous PHE concentration was significantly higher with the biofilm-producing NAH1 than with MATE10. Bacterial adhesion on AC was also investigated. The precoating of AC with PHE increased NAH1 and MATE3 adhesion to the solid surface (>16 and >13%, respectively). Bacterial properties, such as biofilm production and adhesion to AC capacity seemed to be related to their ability to optimize PHE degradation by improving PHE diffusion and reducing diffusion path length.

Matrix stiffness modulates infection of endothelial cells by Listeria monocytogenes via expression of cell surface vimentin.

PubMed

Bastounis, Effie E; Yeh, Yi-Ting; Theriot, Julie A

2018-05-02

Extracellular matrix stiffness (ECM) is one of the many mechanical forces acting on mammalian adherent cells and an important determinant of cellular function. While the effect of ECM stiffness on many aspects of cellular behavior has been previously studied, how ECM stiffness might mediate susceptibility of host cells to infection by bacterial pathogens was hitherto unexplored. To address this open question, we manufactured hydrogels of varying physiologically-relevant stiffness and seeded human microvascular endothelial cells (HMEC-1) on them. We then infected HMEC-1 with the bacterial pathogen Listeria monocytogenes (Lm), and found that adhesion of Lm onto host cells increases monotonically with increasing matrix stiffness, an effect that requires the activity of focal adhesion kinase (FAK). We identified cell surface vimentin as a candidate surface receptor mediating stiffness-dependent adhesion of Lm to HMEC-1 and found that bacterial infection of these host cells is decreased when the amount of surface vimentin is reduced. Our results provide the first evidence that ECM stiffness can mediate the susceptibility of mammalian host cells to infection by a bacterial pathogen.

Measuring the Adhesion Forces for the Multivalent Binding of Vancomycin-Conjugated Dendrimer to Bacterial Cell-Wall Peptide.

PubMed

Peterson, Elizabeth; Joseph, Christine; Peterson, Hannah; Bouwman, Rachael; Tang, Shengzhuang; Cannon, Jayme; Sinniah, Kumar; Choi, Seok Ki

2018-06-19

Multivalent ligand-receptor interaction provides the fundamental basis for the hypothetical notion that high binding avidity relates to the strong force of adhesion. Despite its increasing importance in the design of targeted nanoconjugates, an understanding of the physical forces underlying the multivalent interaction remains a subject of urgent investigation. In this study, we designed three vancomycin (Van)-conjugated dendrimers G5(Van) n ( n = mean valency = 0, 1, 4) for bacterial targeting with generation 5 (G5) poly(amidoamine) dendrimer as a multivalent scaffold and evaluated both their binding avidity and physical force of adhesion to a bacterial model surface by employing surface plasmon resonance (SPR) spectroscopy and atomic force microscopy. The SPR experiment for these conjugates was performed in a biosensor chip surface immobilized with a bacterial cell-wall peptide Lys-d-Ala-d-Ala. Of these, G5(Van) 4 bound most tightly with a K D of 0.34 nM, which represents an increase in avidity by 2 or 3 orders of magnitude relative to a monovalent conjugate G5(Van) 1 or free vancomycin, respectively. By single-molecule force spectroscopy, we measured the adhesion force between G5(Van) n and the same cell-wall peptide immobilized on the surface. The distribution of adhesion forces increased in proportion to vancomycin valency with the mean force of 134 pN at n = 4 greater than 96 pN at n = 1 at a loading rate of 5200 pN/s. In summary, our results are strongly supportive of the positive correlation between the avidity and adhesion force in the multivalent interaction of vancomycin nanoconjugates.

Bacterial inhibition potential of 3D rapid-prototyped magnesium-based porous composite scaffolds–an in vitro efficacy study

PubMed Central

Ma, Rui; Lai, Yu-xiao; Li, Long; Tan, Hong-lue; Wang, Jia-li; Li, Ye; Tang, Ting-ting; Qin, Ling

2015-01-01

Bone infections are common in trauma-induced open fractures with bone defects. Therefore, developing anti-infection scaffolds for repairing bone defects is desirable. This study develoepd novel Mg-based porous composite scaffolds with a basal matrix composed of poly(lactic-co-glycolicacid) (PLGA) and tricalcium phosphate (TCP). A unique low-temperature rapid prototyping technology was used to fabricate the scaffolds, including PLGA/TCP (PT), PLGA/TCP/5%Mg (PT5M), PLGA/TCP/10%Mg (PT10M), and PLGA/TCP/15%Mg (PT15M). The bacterial adhesion and biofilm formation of Staphylococcus aureus were evaluated. The results indicated that the Mg-based scaffolds significantly inhibited bacterial adhesion and biofilm formation compared to PT, and the PT10M and PT15M exhibited significantly stronger anti-biofilm ability than PT5M. In vitro degratation tests revealed that the degradation of the Mg-based scaffolds caused an increase of pH, Mg2+ concentration and osmolality, and the increased pH may be one of the major contributing factors to the antibacterial function of the Mg-based scaffolds. Additionally, the PT15M exhibited an inhibitory effect on cell adhesion and proliferation of MC3T3-E1 cells. In conclusion, the PLGA/TCP/Mg scaffolds could inhibit bacterial adhesion and biofilm formation, and the PT10M scaffold was considered to be an effective composition with considerable antibacterial ability and good cytocompatibility. PMID:26346217

Dosage effect on uropathogenic Escherichia coli anti-adhesion activity in urine following consumption of cranberry powder standardized for proanthocyanidin content: a multicentric randomized double blind study

PubMed Central

2010-01-01

Background Ingestion of cranberry (Vaccinium macrocarpon Ait.) has traditionally been utilized for prevention of urinary tract infections. The proanthocyanidins (PACs) in cranberry, in particular the A-type linkages have been implicated as important inhibitors of primarily P-fimbriated E. coli adhesion to uroepithelial cells. Additional experiments were required to investigate the persistence in urine samples over a broader time period, to determine the most effective dose per day and to determine if the urinary anti-adhesion effect following cranberry is detected within volunteers of different origins. Methods Two separate bioassays (a mannose-resistant hemagglutination assay and an original new human T24 epithelial cell-line assay) have assessed the ex-vivo urinary bacterial anti-adhesion activity on urines samples collected from 32 volunteers from Japan, Hungary, Spain and France in a randomized, double-blind versus placebo study. An in vivo Caenorhabditis elegans model was used to evaluate the influence of cranberry regimen on the virulence of E. coli strain. Results The results indicated a significant bacterial anti-adhesion activity in urine samples collected from volunteers that consumed cranberry powder compared to placebo (p < 0.001). This inhibition was clearly dose-dependent, prolonged (until 24 h with 72 mg of PAC) and increasing with the amount of PAC equivalents consumed in each cranberry powder regimen. An in vivo Caenorhabditis elegans model showed that cranberry acted against bacterial virulence: E. coli strain presented a reduced ability to kill worms after a growth in urines samples of patients who took cranberry capsules. This effect is particularly important with the regimen of 72 mg of PAC. Conclusions Administration of PAC-standardized cranberry powder at dosages containing 72 mg of PAC per day may offer some protection against bacterial adhesion and virulence in the urinary tract. This effect may offer a nyctohemeral protection. PMID:20398248

A marine bacterial adhesion microplate test using the DAPI fluorescent dye: a new method to screen antifouling agents.

PubMed

Leroy, C; Delbarre-Ladrat, C; Ghillebaert, F; Rochet, M J; Compère, C; Combes, D

2007-04-01

To develop a method to screen antifouling agents against marine bacterial adhesion as a sensitive, rapid and quantitative microplate fluorescent test. Our experimental method is based on a natural biofilm formed by mono-incubation of the marine bacterium Pseudoalteromonas sp. D41 in sterile natural sea water in a 96-well polystyrene microplate. The 4'6-diamidino-2-phenylindole dye was used to quantify adhered bacteria in each well. The total measured fluorescence in the wells was correlated with the amount of bacteria showing a detection limit of one bacterium per 5 microm(2) and quantifying 2 x 10(7) to 2 x 10(8) bacteria adhered per cm(2). The antifouling properties of three commercial surface-active agents and chlorine were tested by this method in the prevention of adhesion and also in the detachment of already adhered bacteria. The marine bacterial adhesion inhibition rate depending on the agent concentration showed a sigmoid shaped dose-response curve. This test is well adapted for a rapid and quantitative first screening of antifouling agents directly in seawater in the early steps of marine biofilm formation. In contrast to the usual screenings of antifouling products which detect a bactericidal activity, this test is more appropriate to screen antifouling agents for bacterial adhesion removal or bacterial adhesion inhibition activities. This screening test focuses on the antifouling properties of the products, especially the initial steps of marine biofilm formation.

Single-cell force spectroscopy of the medically important Staphylococcus epidermidis-Candida albicans interaction

NASA Astrophysics Data System (ADS)

Beaussart, Audrey; Herman, Philippe; El-Kirat-Chatel, Sofiane; Lipke, Peter N.; Kucharíková, Soňa; van Dijck, Patrick; Dufrêne, Yves F.

2013-10-01

Despite the clinical importance of bacterial-fungal interactions, their molecular details are poorly understood. A hallmark of such medically important interspecies associations is the interaction between the two nosocomial pathogens Staphylococcus aureus and Candida albicans, which can lead to mixed biofilm-associated infections with enhanced antibiotic resistance. Here, we use single-cell force spectroscopy (SCFS) to quantify the forces engaged in bacterial-fungal co-adhesion, focusing on the poorly investigated S. epidermidis-C. albicans interaction. Force curves recorded between single bacterial and fungal germ tubes showed large adhesion forces (~5 nN) with extended rupture lengths (up to 500 nm). By contrast, bacteria poorly adhered to yeast cells, emphasizing the important role of the yeast-to-hyphae transition in mediating adhesion to bacterial cells. Analysis of mutant strains altered in cell wall composition allowed us to distinguish the main fungal components involved in adhesion, i.e. Als proteins and O-mannosylations. We suggest that the measured co-adhesion forces are involved in the formation of mixed biofilms, thus possibly as well in promoting polymicrobial infections. In the future, we anticipate that this SCFS platform will be used in nanomedicine to decipher the molecular mechanisms of a wide variety of pathogen-pathogen interactions and may help in designing novel anti-adhesion agents.

Co-immobilization of active antibiotics and cell adhesion peptides on calcium based biomaterials.

PubMed

Palchesko, Rachelle N; Buckholtz, Gavin A; Romeo, Jared D; Gawalt, Ellen S

2014-07-01

Two bioactive molecules with unrelated functions, vancomycin and a cell adhesion peptide, were immobilized on the surface of a potential bone scaffold material, calcium aluminum oxide. In order to accomplish immobilization and retain bioactivity three sequential surface functionalization strategies were compared: 1.) vancomycin was chemically immobilized before a cell adhesion peptide (KRSR), 2.) vancomycin was chemically immobilized after KRSR and 3.) vancomycin was adsorbed after binding the cell adhesion peptide. Both molecules remained on the surface and active using all three reaction sequences and after autoclave sterilization based on osteoblast attachment, bacterial turbidity and bacterial zone inhibition test results. However, the second strategy was superior at enhancing osteoblast attachment and significantly decreasing bacterial growth when compared to the other sequences. Copyright © 2014 Elsevier B.V. All rights reserved.

Modification of the surfaces of medical devices to prevent microbial adhesion and biofilm formation.

PubMed

Desrousseaux, C; Sautou, V; Descamps, S; Traoré, O

2013-10-01

The development of devices with surfaces that have an effect against microbial adhesion or viability is a promising approach to the prevention of device-related infections. To review the strategies used to design devices with surfaces able to limit microbial adhesion and/or growth. A PubMed search of the published literature. One strategy is to design medical devices with a biocidal agent. Biocides can be incorporated into the materials or coated or covalently bonded, resulting either in release of the biocide or in contact killing without release of the biocide. The use of biocides in medical devices is debated because of the risk of bacterial resistance and potential toxicity. Another strategy is to modify the chemical or physical surface properties of the materials to prevent microbial adhesion, a complex phenomenon that also depends directly on microbial biological structure and the environment. Anti-adhesive chemical surface modifications mostly target the hydrophobicity features of the materials. Topographical modifications are focused on roughness and nanostructures, whose size and spatial organization are controlled. The most effective physical parameters to reduce bacterial adhesion remain to be determined and could depend on shape and other bacterial characteristics. A prevention strategy based on reducing microbial attachment rather than on releasing a biocide is promising. Evidence of the clinical efficacy of these surface-modified devices is lacking. Additional studies are needed to determine which physical features have the greatest potential for reducing adhesion and to assess the usefulness of antimicrobial coatings other than antibiotics. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

The effect of protein-coated contact lenses on the adhesion and viability of gram negative bacteria.

PubMed

Williams, Timothy J; Schneider, Rene P; Willcox, Mark D P

2003-10-01

Gram negative bacterial adhesion to contact lenses can cause adverse responses. During contact lens wear, components of the tear film adsorb to the contact lens. This study aimed to investigate the effect of this conditioning film on the viability of bacteria. Bacteria adhered to contact lenses which were either unworn, worn for daily-, extended- or overnight-wear or coated with lactoferrin or lysozyme. Numbers of viable and total cells were estimated. The number of viable attached cells was found to be significantly lower than the total number of cells on worn (50% for strain Paer1 on daily-wear lenses) or lactoferrin-coated lenses (56% for strain Paer1). Lysozyme-coated lenses no statistically significant effect on adhesion. The conditioning film gained through wear may not inhibit bacterial adhesion, but may act adversely upon those bacteria that succeed in attaching.

Cellular and molecular investigations of the adhesion and mechanics of Listeria monocytogenes

NASA Astrophysics Data System (ADS)

Eskhan, Asma Omar

Atomic force microscopy has been used to quantify the adherence and mechanical properties of an array of L. monocytogenes strains and their surface biopolymers. First, eight L. monocytogenes strains that represented the two major lineages of the species were compared for their adherence and mechanics at cellular and molecular levels. Our results indicated that strains of lineage' II were characterized by higher adhesion and Young's moduli, longer and more rigid surface biopolymers and lower specific and nonspecific forces when compared to lineage' I strains. Additionally, adherence and mechanical properties of eight L. monocytogenes epidemic and environmental strains were probed. Our results pointed to that environmental and epidemic strains representative of a given lineage were similar in their adherence and mechanical properties when investigated at a cellular level. However, when the molecular properties of the strains were considered, epidemic strains were characterized by higher specific and nonspecific forces, shorter, denser and more flexible biopolymers compared to environmental strains. Second, the role of environmental pH conditions of growth on the adhesion and mechanics of a pathogenic L. monocytogenes EGDe was investigated. Our results pointed to a transition in the adhesion energies for cells cultured at pH 7. In addition, when the types of molecular forces that govern the adhesion were quantified using Poisson statistical approach and using a new proposed method, specific hydrogen-bond energies dominated the bacterial adhesion process. Such a finding is instrumental to researchers designing methods to control bacterial adhesion. Similarly, bacterial cells underwent a transition in their mechanical properties. We have shown that cells cultured at pH 7 were the most rigid compared to those cultured in lower or higher pH conditions of growth. Due to transitions observed in adherence and mechanics when cells were cultured at pH 7, we hypothesized that adhesion and mechanics are correlated. To test this hypothesis, nonadhesive and adhesive models of contact mechanics were used to estimate Young's moduli. Our results indicated that the nonadhesive model of contact mechanics estimated 18 % more rigid bacterial cells. Our results thus point to the importance of considering molecular details when investigating bacterial adhesion and mechanics.

Lubricin: A novel means to decrease bacterial adhesion and proliferation

PubMed Central

Aninwene, George E.; Abadian, Pegah N.; Ravi, Vishnu; Taylor, Erik N.; Hall, Douglas M.; Mei, Amy; Jay, Gregory D.; Goluch, Edgar D.; Webster, Thomas J.

2015-01-01

This study investigated the ability of lubricin (LUB) to prevent bacterial attachment and proliferation on model tissue culture polystyrene surfaces. The findings from this study indicated that LUB was able to reduce the attachment and growth of Staphylococcus aureus on tissue culture polystyrene over the course of 24 h by approximately 13.9% compared to a phosphate buffered saline (PBS)-soaked control. LUB also increased S. aureus lag time (the period of time between the introduction of bacteria to a new environment and their exponential growth) by approximately 27% compared to a PBS-soaked control. This study also indicated that vitronectin (VTN), a protein homologous to LUB, reduced bacterial S. aureus adhesion and growth on tissue culture polystyrene by approximately 11% compared to a PBS-soaked control. VTN also increased the lag time of S. aureus by approximately 43%, compared to a PBS-soaked control. Bovine submaxillary mucin was studied because there are similarities between it and the center mucin-like domain of LUB. Results showed that the reduction of S. aureus and Staphylococcus epidermidis proliferation on mucin coated surfaces was not as substantial as that seen with LUB. In summary, this study provided the first evidence that LUB reduced the initial adhesion and growth of both S. aureus and S. epidermidis on a model surface to suppress biofilm formation. These reductions in initial bacteria adhesion and proliferation can be beneficial for medical implants and, although requiring more study, can lead to drastically improved patient outcomes. PMID:24737699

Adhesive sealing of dentin surfaces in vitro: A review

PubMed Central

Abu-Nawareg, Manar M; Zidan, Ahmed Z; Zhou, Jianfeng; Agee, Kelli; Chiba, Ayaka; Tagami, Jungi; Pashley, David H

2016-01-01

Purpose The purpose of this review is to describe the evolution of the use of dental adhesives to form a tight seal of freshly prepared dentin to protect the pulp from bacterial products, during the time between crown preparation and final cementum of full crowns. The evolution of these “immediate dentin sealants” follows the evolution of dental adhesives, in general. That is, they began with multiple-step, etch-and-rinse adhesives, and then switched to the use of simplified adhesives. Methods Literature was reviewed for evidence that bacteria or bacterial products diffusing across dentin can irritate pulpal tissues before and after smear layer removal. Smear layers can be solubilized by plaque organisms within 7–10 days if they are directly exposed to oral fluids. It is likely that smear layers covered by temporary restorations may last more than one month. As long as smear layers remain in place, they can partially seal dentin. Thus, many in vitro studies evaluating the sealing ability of adhesive resins use smear layer-covered dentin as a reference condition. Surprisingly, many adhesives do not seal dentin as well as do smear layers. Results Both in vitro and in vivo studies show that resin-covered dentin allows dentinal fluid to cross polymerized resins. The use of simplified single bottle adhesives to seal dentin was a step backwards. Currently, most authorities use either 3-step adhesives such as Scotchbond Multi-Purposea or OptiBond FLb or two-step self-etching primer adhesives, such as Clearfil SEc, Unifil Bondd or AdheSEe, respectfully. PMID:26846037

Structure, Function, and Assembly of Adhesive Organelles by Uropathogenic Bacteria

PubMed Central

Chahales, Peter; Thanassi, David G.

2015-01-01

Bacteria assemble a wide range of adhesive proteins, termed adhesins, to mediate binding to receptors and colonization of surfaces. For pathogenic bacteria, adhesins are critical for early stages of infection, allowing the bacteria to initiate contact with host cells, colonize different tissues, and establish a foothold within the host. The adhesins expressed by a pathogen are also critical for bacterial-bacterial interactions and the formation of bacterial communities such as biofilms. The ability to adhere to host tissues is particularly important for bacteria that colonize sites such as the urinary tract, where the flow of urine functions to maintain sterility by washing away non-adherent pathogens. Adhesins vary from monomeric proteins that are directly anchored to the bacterial surface to polymeric, hairlike fibers that extend out from the cell surface. These latter fibers are termed pili or fimbriae, and were among the first identified virulence factors of uropathogenic Escherichia coli. Studies since then have identified a range of both pilus and non-pilus adhesins that contribute to bacterial colonization of the urinary tract, and have revealed molecular details of the structures, assembly pathways, and functions of these adhesive organelles. In this review, we describe the different types of adhesins expressed by both Gram-negative and Gram-positive uropathogens, what is known about their structures, how they are assembled on the bacterial surface, and the functions of specific adhesins in the pathogenesis of urinary tract infections. PMID:26542038

Influence of day and night wear on surface properties of silicone hydrogel contact lenses and bacterial adhesion.

PubMed

Vermeltfoort, Pit B J; Rustema-Abbing, Minie; de Vries, Joop; Bruinsma, Gerda M; Busscher, Henk J; van der Linden, Matthijs L; Hooymans, Johanna M M; van der Mei, Henny C

2006-06-01

The aim of this study was to determine the effect of continuous wear on physicochemical surface properties of silicone hydrogel (S-H) lenses and their susceptibility to bacterial adhesion. In this study, volunteers wore 2 pairs of either "lotrafilcon A" or "balafilcon A" S-H contact lenses. The first pair was worn continuously for a week and the second pair for 4 weeks. One lens of each pair was used for surface characterization and the other one for bacterial adhesion experiments. Lens surfaces were characterized by examination of their wettability, roughness, elemental composition, and proteins attached to their surfaces. Adhesion of Staphylococcus aureus 835 and Pseudomonas aeruginosa #3 to a lens was studied using a parallel plate flow chamber. Before use, the lotrafilcon A lens was rougher than the balafilcon A lens and had a lower water contact angle and a higher affinity for S. aureus 835. After wear, both lens types had similar water contact angles, whereas the differences in elemental surface composition decreased as well. S. aureus 835 adhered in higher numbers to worn balafilcon A lenses, whereas the opposite was seen for P. aeruginosa #3. The initial deposition rates of both bacterial strains to lotrafilcon A lenses decreased by wearing and were found to correlate significant (P < 0.001) with the surface roughness of worn lenses. In this study, the differences in surface properties between 2 types of S-H lenses were found to change after 1 week of continuous wear. Generally, bacteria adhered in lower numbers and less tenaciously to worn lenses, except S. aureus 835, adhering in higher numbers to worn balafilcon A lenses.

Adhesive interactions between milk fat globule membrane and Lactobacillus rhamnosus GG inhibit bacterial attachment to Caco-2 TC7 intestinal cell.

PubMed

Guerin, Justine; Soligot, Claire; Burgain, Jennifer; Huguet, Marion; Francius, Gregory; El-Kirat-Chatel, Sofiane; Gomand, Faustine; Lebeer, Sarah; Le Roux, Yves; Borges, Frederic; Scher, Joël; Gaiani, Claire

2018-07-01

Milk is the most popular matrix for the delivery of lactic acid bacteria, but little is known about how milk impacts bacterial functionality. Here, the adhesion mechanisms of Lactobacillus rhamnosus GG (LGG) surface mutants to a milk component, the milk fat globule membrane (MFGM), were compared using atomic force microscopy (AFM). AFM results revealed the key adhesive role of the LGG SpaCBA pilus in relation to MFGM. A LGG mutant without exopolysaccharides but with highly exposed pili improved the number of adhesive events between LGG and MFGM compared to LGG wild type (WT). In contrast, the number of adhesive events decreased significantly for a LGG mutant without SpaCBA pili. Moreover, the presence of MFGM in the dairy matrix was found to decrease significantly the bacterial attachment ability to Caco-2 TC7 cells. This work thus demonstrated a possible competition between LGG adhesion to MFGM and to epithelial intestinal cells. This competition could negatively impact the adhesion capacity of LGG to intestinal cells in vivo, but requires further substantiation. Copyright © 2018 Elsevier B.V. All rights reserved.

Titanium Surface Chemical Composition Interferes in the Pseudomonas aeruginosa Biofilm Formation.

PubMed

Nunes Filho, Antonio; Aires, Michelle de Medeiros; Braz, Danilo Cavalcante; Hinrichs, Ruth; Macedo, Alexandre José; Alves, Clodomiro

2018-02-01

Bacterial adhesion on three different surfaces: untreated Ti, plasma nitriding, and plasma carbonitriding Ti substrates were investigated. The samples were placed in bacterial cultures of Pseudomonas aeruginosa to assess biofilm formation. The correlation between the amount of bacteria attached to the surface after a lapse of time with nanotopography and physicochemical properties was performed. TiN showed the highest capacity to avoid bacterial adhesion, while presenting intermediate roughness and wettability. Although the surface of TiCN had the highest surface roughness and low contact angle (high wettability), bacterial adhesion was intermediate on this sample. Untreated Ti, even though presenting a smooth surface and low wettability, had the highest tendency to form biofilms. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Assessment of the adhesive properties of the bacterial polysaccharide FucoPol.

PubMed

Araújo, Diana; Alves, Vitor D; Campos, Joana; Coelhoso, Isabel; Sevrin, Chantal; Grandfils, Christian; Freitas, Filomena; Reis, Maria A M

2016-11-01

To address the industry's interest in finding novel biobased glues, the adhesive properties of the bacterial polysaccharide FucoPol were evaluated through shear bond strength tests. A FucoPol solution was used to bond different materials, namely, wood, glass, cardboard and cellulose acetate film. The shear strength was compared to that of the same adherends bonded with commercial synthetic glues. Wood-wood joints bonded with FucoPol formulation withstood 742.2±9.8kPa shear strength without detachment. FucoPol adhesive capacity for cardboard was comparable to that of the tested commercial glues (425±8.9kPa), yielding similar shear strength values (416.0±12.9kPa), while improved performance was shown for glass (115.1±26.2kPa) and cellulose acetate film (153.7±11.3kPa) comparing to the commercial glues (67.7-97.5kPa and 79.4-92.7kPa, respectively). This study demonstrates the adhesive properties of FucoPol, opening up the opportunity of using this bacterial polysaccharide for the development of new natural water-based glues, suitable to bond different materials. Copyright © 2016 Elsevier B.V. All rights reserved.

Floating and Tether-Coupled Adhesion of Bacteria to Hydrophobic and Hydrophilic Surfaces

PubMed Central

2018-01-01

Models for bacterial adhesion to substratum surfaces all include uncertainty with respect to the (ir)reversibility of adhesion. In a model, based on vibrations exhibited by adhering bacteria parallel to a surface, adhesion was described as a result of reversible binding of multiple bacterial tethers that detach from and successively reattach to a surface, eventually making bacterial adhesion irreversible. Here, we use total internal reflection microscopy to determine whether adhering bacteria also exhibit variations over time in their perpendicular distance above surfaces. Streptococci with fibrillar surface tethers showed perpendicular vibrations with amplitudes of around 5 nm, regardless of surface hydrophobicity. Adhering, nonfibrillated streptococci vibrated with amplitudes around 20 nm above a hydrophobic surface. Amplitudes did not depend on ionic strength for either strain. Calculations of bacterial energies from their distances above the surfaces using the Boltzman equation showed that bacteria with fibrillar tethers vibrated as a harmonic oscillator. The energy of bacteria without fibrillar tethers varied with distance in a comparable fashion as the DLVO (Derjaguin, Landau, Verwey, and Overbeek)-interaction energy. Distance variations above the surface over time of bacteria with fibrillar tethers are suggested to be governed by the harmonic oscillations, allowed by elasticity of the tethers, piercing through the potential energy barrier. Bacteria without fibrillar tethers “float” above a surface in the secondary energy minimum, with their perpendicular displacement restricted by their thermal energy and the width of the secondary minimum. The distinction between “tether-coupled” and “floating” adhesion is new, and may have implications for bacterial detachment strategies. PMID:29649869

Screening host proteins required for bacterial adherence after H9N2 virus infection.

PubMed

Ma, Li-Li; Sun, Zhen-Hong; Xu, Yu-Lin; Wang, Shu-Juan; Wang, Hui-Ning; Zhang, Hao; Hu, Li-Ping; Sun, Xiao-Mei; Zhu, Lin; Shang, Hong-Qi; Zhu, Rui-Liang; Wei, Kai

2018-01-01

H9N2 subtype low pathogenic avian influenza virus (LPAIV) is distributed worldwide and causes great economic losses in the poultry industry, especially when complicated with other bacterial infections. Tissue damages caused by virus infection provide an opportunity for bacteria invasion, but this mechanism is not sufficient for low pathogenic strains. Moreover, although H9N2 virus infection was demonstrated to promote bacterial infection in several studies, its mechanism remained unclear. In this study, infection experiments in vivo and in vitro demonstrated that the adhesion of Escherichia coli (E. coli) to host cells significantly increased after H9N2 virus infection, and this increase was not caused by pathological damages. Subsequently, we constructed a late chicken embryo infection model and used proteomics techniques to analyze the expression of proteins associated with bacterial adhesion after H9N2 virus infection. A total of 279 significantly differential expressed proteins were detected through isobaric tags for relative and absolute quantitation (iTRAQ) coupled with nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) analysis. The results of Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that differentially expressed proteins were enriched in host innate immunity; cell proliferation, differentiation, and apoptosis; and pathogenicity-related signaling pathways. Finally, we screened out several proteins, such as TGF-β1, integrins, cortactin, E-cadherin, vinculin, and fibromodulin, which were probably associated with bacterial adhesion. The study analyzed the mechanism of secondary bacterial infection induced by H9N2 virus infection from a novel perspective, which provided theoretical and data support for investigating the synergistic infection mechanism between the H9N2 virus and bacteria. Copyright © 2017 Elsevier B.V. All rights reserved.

Bacillus cereus Certhrax ADP-ribosylates Vinculin to Disrupt Focal Adhesion Complexes and Cell Adhesion*

PubMed Central

Simon, Nathan C.; Barbieri, Joseph T.

2014-01-01

Bacillus cereus is often associated with mild to moderate gastroenteritis; however, some recent isolates cause inhalational anthrax-like diseases and death. These potential emerging human pathogens express multiple virulence factors. B. cereus strain G9241 expresses anthrax toxin, several polysaccharide capsules, and the novel ADP-ribosyltransferase, Certhrax. In this study, we show that Certhrax ADP-ribosylates Arg-433 of vinculin, a protein that coordinates actin cytoskeleton and extracellular matrix interactions. ADP-ribosylation of vinculin disrupted focal adhesion complexes and redistributed vinculin to the cytoplasm. Exogenous vinculin rescued these phenotypes. This provides a mechanism for strain G9241 to breach host barrier defenses and promote bacterial growth and spread. Certhrax is the first bacterial toxin to add a post-translational modification to vinculin to disrupt the actin cytoskeleton. PMID:24573681

Prevention of bacterial adhesion to zwitterionic biocompatible mesoporous glasses.

PubMed

Sánchez-Salcedo, Sandra; García, Ana; Vallet-Regí, María

2017-07-15

Novel materials, based on Mesoporous Bioactive Glasses (MBGs) in the ternary system SiO 2 -CaO-P 2 O 5 , decorated with (3-aminopropyl)triethoxysilane (APTES) and subsequently with amino acid Lysine (Lys), by post-grafting method on the external surface of the glasses (named MBG-NH 2 and MBG-Lys), are reported. The surface functionalization with organic groups did not damage the mesoporous network and their structural and textural properties were also preserved despite the high solubility of MBG matrices. The incorporation of Lys confers a zwitterionic nature to these MBG materials due to the presence of adjacent amine and carboxylic groups in the external surface. At physiologic pH, this coexistence of basic amine and carboxilic acid groups from anchored Lys provided zero surface charge named zwitterionic effect. This behaviour could give rise to potential applications of antibacterial adhesion. Therefore, in order to assess the influence of zwitterionic nature in in vitro bacterial adhesion, studies were carried out with Staphylococcus aureus. It was demonstrated that the efficient interaction of these zwitterionic pairs onto the MBG surfaces reduced bacterial adhesion up to 99.9% compared to bare MBGs. In order to test the suitability of zwitterionic MBGs materials as bone grafts, their cytocompatibility was investigated in vitro with MC3T3-E1 preosteoblasts. These findings suggested that the proposed surface functionalization strategy provided MBG materials with notable antibacterial adhesion properties, hence making these materials promising candidates for local bone infection therapy. The present research work is focused in finding a preventive treatment of bone infection based on Mesoporous Bioactive Glasses (MBGs) with antibacterial adhesion properties obtained by zwitterionic surface modification. MBGs exhibit unique nanostructural, textural and bioactive characteristics. The novelty and originality of this manuscript is based on the design and optimization of a straightforward functionalization method capable of providing MBGs with zwitterionic surfaces that are able to inhibit bacterial adhesion without affecting their cytocompatibility. This new characteristic enhanced the MBG properties to avoid the bacterial adherence onto the implant surfaces for bone tissue engineering applications. Subsequently, it could help to decrease the infection rates after implantation surgery, which represents one of the most serious complications associated to surgical treatments of bone diseases and fractures. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Spectral force analysis using atomic force microscopy reveals the importance of surface heterogeneity in bacterial and colloid adhesion to engineered surfaces.

PubMed

Ma, Huilian; Winslow, Charles J; Logan, Bruce E

2008-04-01

Coatings developed to reduce biofouling of engineered surfaces do not always perform as expected based on their native properties. One reason is that a relatively small number of highly adhesive sites, or the heterogeneity of the coated surface, may control the overall response of the system to initial bacterial deposition. It is shown here using an approach we call spectral force analysis (SFA), based on force volume imaging of the surface with atomic force microscopy, that the behavior of surfaces and coatings can be better understood relative to bacterial adhesion. The application of vapor deposited TiO(2) metal oxide increased bacterial and colloid adhesion, but coating the surface with silica oxide reduced adhesion in a manner consistent with SFA based on analysis of the "stickiest" sites. Application of a TiO(2)-based paint to a surface produced a relatively non-fouling surface. Addition of a hydrophilic layer coating to this surface should have decreased fouling. However, it was observed that this coating actually increased fouling. Using SFA it was shown that the reason for the increased adhesion of bacteria and particles to the hydrophilic layer was that the surface produced by this coating was highly heterogeneous, resulting in a small number of sites that created a stickier surface. These results show that while it is important to manufacture surfaces with coatings that are relatively non-adhesive to bacteria, it is also essential that these coatings have a highly uniform surface chemistry.

Spatial variation in deposition rate coefficients of an adhesion-deficient bacterial strain in quartz sand.

PubMed

Tong, Meiping; Camesano, Terri A; Johnson, William P

2005-05-15

The transport of bacterial strain DA001 was examined in packed quartz sand under a variety of environmentally relevant ionic strength and flow conditions. Under all conditions, the retained bacterial concentrations decreased with distance from the column inlet at a rate that was faster than loglinear, indicating that the deposition rate coefficient decreased with increasing transport distance. The hyperexponential retained profile contrasted againstthe nonmonotonic retained profiles that had been previously observed for this same bacterial strain in glass bead porous media, demonstrating that the form of deviation from log-linear behavior is highly sensitive to system conditions. The deposition rate constants in quartz sand were orders of magnitude below those expected from filtration theory, even in the absence of electrostatic energy barriers. The degree of hyperexponential deviation of the retained profiles from loglinear behavior did not decrease with increasing ionic strength in quartz sand. These observations demonstrate thatthe observed low adhesion and deviation from log-linear behavior was not driven by electrostatic repulsion. Measurements of the interaction forces between DA001 cells and the silicon nitride tip of an atomic force microscope (AFM) showed that the bacterium possesses surface polymers with an average equilibrium length of 59.8 nm. AFM adhesion force measurements revealed low adhesion affinities between silicon nitride and DA001 polymers with approximately 95% of adhesion forces having magnitudes < 0.8 nN. Steric repulsion due to surface polymers was apparently responsible for the low adhesion to silicon nitride, indicating that steric interactions from extracellular polymers controlled DA001 adhesion deficiency and deviation from log-linear behavior on quartz sand.

Bacterial leakage in root canals filled with AH Plus and dentine bonding agents.

PubMed

Navarro-Escobar, Esther; Baca, Pilar; Ruiz-Linares, Matilde; Arias-Moliz, Maria Teresa; Perez-Heredia, Mercedes; Ferrer-Luque, Carmen Maria

2014-11-01

The aim of this study was to compare the efficacy of different dentine adhesives in delaying the coronal bacterial leakage of Enterococcus faecalis in filled root canals. Materials and methods. Ninety-five lower incisors of patients >65 years of age were instrumented using the ProTaper system and were irrigated with 1 mL of 2.5% sodium hypochlorite (NaOCl) alternated with 1 mL 17% EDTA between each file change. Final irrigation was performed with 5 mL of 17% EDTA and then flushed with 5 mL of distilled water. The teeth were randomly divided into five experimental groups (n = 15/group) and one of the following dentine adhesives was applied: (1) AdheSE; (2) Excite DSC; (3) Clearfil Protect Bond; (4) One Coat 7.0; or (5) Control group without adhesive. After filling the root canals, the samples were mounted on a double chamber device to evaluate the bacterial filtration of E. faecalis during a period of 240 days. The results underwent non-parametric Kaplan-Meier survival analysis and comparisons among groups were done using the Log-Rank test. At 240 days, E. faecalis was detected in samples of all groups in the lower chamber. The highest survival value was obtained by One Coat 7.0, giving statistically significant differences from the other groups, whereas Clearfil Protect Bond, AdheSE and Excite DSC showed similar behaviours, likewise similar to the Control group. One Coat 7.0 adhesive system provides the longest survival value to delay E. faecalis coronal leakage in filled root canals.

Comparison of candidate materials for a synthetic osteo-odonto keratoprosthesis device.

PubMed

Tan, Xiao Wei; Perera, A Promoda P; Tan, Anna; Tan, Donald; Khor, K A; Beuerman, Roger W; Mehta, Jodhbir S

2011-01-05

Osteo-odonto keratoprosthesis is one of the most successful forms of keratoprosthesis surgery for end-stage corneal and ocular surface disease. There is a lack of detailed comparison studies on the biocompatibilities of different materials used in keratoprosthesis. The aim of this investigation was to compare synthetic bioinert materials used for keratoprosthesis surgery with hydroxyapatite (HA) as a reference. Test materials were sintered titanium oxide (TiO(2)), aluminum oxide (Al(2)O(3)), and yttria-stabilized zirconia (YSZ) with density >95%. Bacterial adhesion on the substrates was evaluated using scanning electron microscopy and the spread plate method. Surface properties of the implant discs were scanned using optical microscopy. Human keratocyte attachment and proliferation rates were assessed by cell counting and MTT assay at different time points. Morphologic analysis and immunoblotting were used to evaluate focal adhesion formation, whereas cell adhesion force was measured with a multimode atomic force microscope. The authors found that bacterial adhesion on the TiO(2), Al(2)O(3), and YSZ surfaces were lower than that on HA substrates. TiO(2) significantly promoted keratocyte proliferation and viability compared with HA, Al(2)O(3,) and YSZ. Immunofluorescent imaging analyses, immunoblotting, and atomic force microscope measurement revealed that TiO(2) surfaces enhanced cell spreading and cell adhesion compared with HA and Al(2)O(3). TiO(2) is the most suitable replacement candidate for use as skirt material because it enhanced cell functions and reduced bacterial adhesion. This would, in turn, enhance tissue integration and reduce device failure rates during keratoprosthesis surgery.

Surface topography of composite restorative materials following ultrasonic scaling and its Impact on bacterial plaque accumulation. An in-vitro SEM study.

PubMed

Hossam, A Eid; Rafi, A Togoo; Ahmed, A Saleh; Sumanth, Phani Cr

2013-06-01

This is an in vitro study to investigate the effects of ultrasonic scaling on the surface roughness and quantitative bacterial count on four different types of commonly used composite restorative materials for class V cavities. Nanofilled, hybrid, silorane and flowable composites were tested. Forty extracted teeth served as specimen and were divided into 4 groups of 10 specimens, with each group receiving a different treatment and were examined by a Field emission scanning electron microscope. Bacterial suspension was then added to the pellicle-coated specimens, and then bacterial adhesion was analyzed by using image analyzing program. Flowable and silorane-based composites showed considerably smoother surfaces and lesser bacterial count in comparison to other types, proving that bacterial adhesion is directly proportional to surface roughness. The use of ultrasonic scalers affects the surfaces of composite restorative materials. Routine periodontal scaling should be carried out very carefully, and polishing of the scaled surfaces may overcome the alterations in roughness, thus preventing secondary caries, surface staining, plaque accumulation and subsequent periodontal inflammation. How to cite this article: Eid H A, Togoo R A, Saleh A A, Sumanth C R. Surface Topography of Composite Restorative Materials following Ultrasonic Scaling and its Impact on Bacterial Plaque Accumulation. An In-Vitro SEM Study. J Int Oral Health 2013; 5(3):13-19.

Surface topography of composite restorative materials following ultrasonic scaling and its Impact on bacterial plaque accumulation. An in-vitro SEM study

PubMed Central

Hossam, A. Eid; Rafi, A. Togoo; Ahmed, A Saleh; Sumanth, Phani CR

2013-01-01

Background: This is an in vitro study to investigate the effects of ultrasonic scaling on the surface roughness and quantitative bacterial count on four different types of commonly used composite restorative materials for class V cavities. Materials & Methods: Nanofilled, hybrid, silorane and flowable composites were tested. Forty extracted teeth served as specimen and were divided into 4 groups of 10 specimens, with each group receiving a different treatment and were examined by a Field emission scanning electron microscope. Bacterial suspension was then added to the pellicle-coated specimens, and then bacterial adhesion was analyzed by using image analyzing program. Results: Flowable and silorane-based composites showed considerably smoother surfaces and lesser bacterial count in comparison to other types, proving that bacterial adhesion is directly proportional to surface roughness. Conclusion: The use of ultrasonic scalers affects the surfaces of composite restorative materials. Routine periodontal scaling should be carried out very carefully, and polishing of the scaled surfaces may overcome the alterations in roughness, thus preventing secondary caries, surface staining, plaque accumulation and subsequent periodontal inflammation. How to cite this article: Eid H A, Togoo R A, Saleh A A, Sumanth C R. Surface Topography of Composite Restorative Materials following Ultrasonic Scaling and its Impact on Bacterial Plaque Accumulation. An In-Vitro SEM Study. J Int Oral Health 2013; 5(3):13-19. PMID:24155597

Stability and effectiveness against bacterial adhesion of poly(ethylene oxide) coatings in biological fluids.

PubMed

Roosjen, Astrid; de Vries, Joop; van der Mei, Henny C; Norde, Willem; Busscher, Henk J

2005-05-01

Poly(ethylene oxide) (PEO) coatings have been shown to reduce the adhesion of different microbial strains and species and thus are promising as coatings to prevent biomaterial-centered infection of medical implants. Clinically, however, PEO coatings are not yet applied, as little is known about their stability and effectiveness in biological fluids. In this study, PEO coatings coupled to a glass substratum through silyl ether bonds were exposed for different time intervals to saliva, urine, or phosphate-buffered saline (PBS) as a reference at 37 degrees C. After exposure, the effectiveness of the coatings against bacterial adhesion was assessed in a parallel plate flow chamber. The coatings appeared effective against Staphylococcus epidermidis adhesion for 24, 48, and 0.5 h in PBS, urine, and saliva, respectively. Using XPS and contact-angle measurements, the variations in effectiveness could be attributed to conditioning film formation. The overall short stability results from hydrolysis of the coupling of the PEO chains to the substratum. (c) 2005 Wiley Periodicals, Inc.

Evidence of variable bacterial colonization on coloured elastomeric ligatures during orthodontic treatment: An intermodular comparative study.

PubMed

Sharma, Ravish; Sharma, Kavita; Sawhney, Rajesh

2018-03-01

Besides, other factors, the choice of materials used as orthodontic ligatures could be one of the many tools to counter the effects of microbial adhesion, that culminates into dental ailments. Therefore, we assessed bacterial adhesion on elastomeric ligatures with special reference to coloured elastomeric rings during orthodontic treatment. A split mouth study, involving 240 samples of different elastomeric ligatures from forty orthodontic patients possessing good oral hygiene was carried out. The archwire was ligated to the brackets on both arches with elastomeric rings (superslick, clear transparent , blue and pink) at predetermined quadrants. After six weeks, ligatures from second premolars were removed and processed for bacterial enumeration using standard techniques. Bacterial counts were also determined for stimulated saliva samples taken at 0 and 6 weeks. A statistically significant difference in bacterial counts was obtained amongst different elastomeric modules used. Maximum bacterial counts were found on conventional pigmented elastomeric modules, followed by Superslick module and clear module. More number of bacteria associated with the conventional pink as compared to the conventional blue pigmented modules, however it was not statistically significant. The three bacterial genera Streptococcus Staphylococcus and Aerobic Lactobacilli adhered to elastomeric modules in following predominant pattern i.e. Conventional pink>Conventional Blue>Superslick>Clear. The studies evidenced colour and material dependent bacterial colonization on orthodontic modules and could be an indicator of bacterial biofilm forming potential based on surface chemistries and a clinically efficacious tool to redesign conventional and modified elastomeric rings as orthodontic ligation accessories. Key words: Bacterial colonization, biofilm, coloured elastomers, orthodontic ligatures.

Fabrication of microtemplates for the control of bacterial immobilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyahara, Yasuhiro; Mitamura, Koji; Saito, Nagahiro

2009-09-15

The authors described a region-selective immobilization methods of bacteria by using superhydrophobic/superhydrophilic and superhydrophobic/poly(ethylene glycol) (PEG) micropatterns for culture scaffold templates. In the case of superhydrophobic/superhydrophilic micropatterns, the superhydrophobic surface was prepared first by microwave-plasma enhanced chemical vapor deposition (MPECVD) from trimethylmethoxysilane. Then the superhydrophilic regions were fabricated by irradiating the superhydrophobic surface with vuv light through a stencil mask. In the case of the superhydrophobic/PEG micropatterned surfaces, PEG surfaces were fabricated first by chemical reaction of ester groups of p-nitrophenyl PEG with NH{sub 2} group of NH{sub 2}-terminated self assembled monolayer from n-6-hexyl-3-aminopropyltrimethoxysilane. The superhydrophobic regions were fabricated bymore » MPECVD thorough a stencil mask. In this study four bacteria were selected from viewpoint of peptidoglycan cell wall (E. coli versus B. subtilis), extracellular polysaccharide (E.coli versus P. stutzeri, P. aeruginosa), and growth rate (P. stutzeri versus P. aeruginosa). The former micropattern brought discrete adhesions of E. coli and B. subtilis specifically on the hydrophobic regions, Furthermore, using the superhydrophobic/PEG micropattern, adhesion of bacteria expanded for E. coli, B. subtilis, P. stutzeri, and P. aeruginosa. They observed a high bacterial adhesion onto superhydrophobic surfaces and the inhibitive effect of bacterial adhesion on PEG surfaces.« less

Effects of Material Properties on Bacterial Adhesion and Biofilm Formation.

PubMed

Song, F; Koo, H; Ren, D

2015-08-01

Adhesion of microbes, such as bacteria and fungi, to surfaces and the subsequent formation of biofilms cause multidrug-tolerant infections in humans and fouling of medical devices. To address these challenges, it is important to understand how material properties affect microbe-surface interactions and engineer better nonfouling materials. Here we review the recent progresses in this field and discuss the main challenges and opportunities. In particular, we focus on bacterial biofilms and review the effects of surface energy, charge, topography, and stiffness of substratum material on bacterial adhesion. We summarize how these surface properties influence oral biofilm formation, and we discuss the important findings from nondental systems that have potential applications in dental medicine. © International & American Associations for Dental Research 2015.

Protein deposition and its effect on bacterial adhesion to contact lenses.

PubMed

Omali, Negar Babaei; Zhu, Hua; Zhao, Zhenjun; Willcox, Mark D P

2013-06-01

Bacterial adhesion to contact lenses is believed to be the initial step for the development of several adverse reactions that occur during lens wear such as microbial keratitis. This study examined the effect of combinations of proteins on the adhesion of bacteria to contact lenses. Unworn balafilcon A and senofilcon A lenses were soaked in commercially available pure protein mixtures to achieve the same amount of various proteins as found ex vivo. These lenses were then exposed to Pseudomonas aeruginosa and Staphylococcus aureus. Following incubation, the numbers of P. aeruginosa or S. aureus that adhered to the lenses were measured. The possible effect of proteins on bacterial growth was investigated by incubating bacteria in medium containing protein. Although there was a significant (p < 0.003) increase in the total or viable counts of one strain of S. aureus (031) on balafilcon A lenses soaked in the lysozyme/lactoferrin combination, the protein adhered to lenses did not alter the adhesion of any other strains of P. aeruginosa or S. aureus (p > 0.05). Growth of S. aureus 031 (p < 0.0001) but not of P. aeruginosa 6294 was stimulated by addition of lysozyme/lactoferrin combination (2.8/0.5 mg/mL). Addition of lipocalin did not affect the growth of any strains tested (p > 0.05). Adsorption of amounts of lysozyme and lactoferrin or lipocalin equivalent to those extracted from worn contact lenses did not affect the adhesion of most strains of S. aureus or P. aeruginosa to lens surfaces.

The effects of titanium nitride-coating on the topographic and biological features of TPS implant surfaces.

PubMed

Annunziata, Marco; Oliva, Adriana; Basile, Maria Assunta; Giordano, Michele; Mazzola, Nello; Rizzo, Antonietta; Lanza, Alessandro; Guida, Luigi

2011-11-01

Titanium nitride (TiN) coating has been proposed as an adjunctive surface treatment aimed to increase the physico-mechanical and aesthetic properties of dental implants. In this study we investigated the surface characteristics of TiN-coated titanium plasma sprayed (TiN-TPS) and uncoated titanium plasma sprayed (TPS) surfaces and their biological features towards both primary human bone marrow mesenchymal stem cells (BM-MSC) and bacterial cultures. 15 mm×1 mm TPS and TiN-TPS disks (P.H.I. s.r.l., San Vittore Olona, Milano, Italy) were topographically analysed by confocal optical profilometry. Primary human BM-MSC were obtained from healthy donors, isolated and expanded. Cells were seeded on the titanium disks and cell adhesion, proliferation, protein synthesis and osteoblastic differentiation in terms of alkaline phosphatase activity, osteocalcin synthesis and extracellular mineralization, were evaluated. Furthermore, adhesion and proliferation of Streptococcus pyogenes and Streptococcus sanguinis on both surfaces were also analysed. TiN-TPS disks showed a decreased roughness (about 50%, p < 0.05) and a decreased bacterial adhesion and proliferation compared to TPS ones. No difference (p > 0.05) in terms of BM-MSC adhesion, proliferation and osteoblastic differentiation between TPS and TiN-TPS surfaces was found. TiN coating showed to modify the topographical characteristics of TPS titanium surfaces and to significantly reduce bacterial adhesion and proliferation, although maintaining their biological affinity towards bone cell precursors. Copyright © 2011 Elsevier Ltd. All rights reserved.

Moxifloxacin superior to cefuroxime in reducing bacterial adhesion of Staphylococcus epidermidis on hydrophobic intraocular lenses.

PubMed

Benbouzid, Fathalah; Kodjikian, Laurent; Hartmann, Daniel; Renaud, François; Baillif, Stéphanie

2016-02-01

To compare the anti-adhesive effect of cefuroxime and moxifloxacin on the primary attachment phase of Staphylococcus epidermidis on hydrophobic acrylic intraocular lenses (IOLs). Forty hydrophobic acrylic IOLs were used. Two groups of IOLs were soaked in a moxifloxacin (Mox-T1: 0.5 mg/0.1 ml) or a cefuroxime (Cef-T1: cefuroxime 1 mg/0.1 ml) solution before incubation in a S. epidermidis bacterial suspension. Two other groups were incubated in the bacterial suspension before antibiotics (Cef-T2 and Mox-T2) were added. The control group (Ctrl) consisted of IOLs incubated in the bacterial suspension. After incubation, IOLs were sonicated and vortexed. The resultant suspension was spread over a nutritive agar plate. Bacterial colonies were counted after 24 hr of incubation. Mean number of colony-forming units per IOL was Cef-T1: 184 × 10(3) (SE: 5.24; SD: 28.21), Cef-T2: 117 × 10(3) (SE: 5.74; SD: 30.37), Mox-T1: 1.27 × 10(3) (SE: 0.12; SD: 0.61), Mox-T2: 25 × 10(3) (SE:1.98; SD: 9.72) and Ctrl: 361 × 10(3) (SE: 26.9; SD: 107.6). The number of adhering bacteria did not vary whether cefuroxime was added before or after IOL incubation in the bacterial suspension (p = 0.132). Moxifloxacin was more effective in reducing the number of adhering bacteria when used before IOL incubation (p < 0.001). Overall for T1 and T2, moxifloxacin was more effective than cefuroxime in reducing bacterial adhesion on IOLs (p < 0.001). Moxifloxacin and cefuroxime significantly reduced S. epidermidis adhesion on hydrophobic acrylic IOLs. The anti-adhesive effect was superior with moxifloxacin. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Trimeric autotransporter adhesins contribute to Actinobacillus pleuropneumoniae pathogenicity in mice and regulate bacterial gene expression during interactions between bacteria and porcine primary alveolar macrophages.

PubMed

Qin, Wanhai; Wang, Lei; Zhai, Ruidong; Ma, Qiuyue; Liu, Jianfang; Bao, Chuntong; Zhang, Hu; Sun, Changjiang; Feng, Xin; Gu, Jingmin; Du, Chongtao; Han, Wenyu; Langford, P R; Lei, Liancheng

2016-01-01

Actinobacillus pleuropneumoniae is an important pathogen that causes respiratory disease in pigs. Trimeric autotransporter adhesin (TAA) is a recently discovered bacterial virulence factor that mediates bacterial adhesion and colonization. Two TAA coding genes have been found in the genome of A. pleuropneumoniae strain 5b L20, but whether they contribute to bacterial pathogenicity is unclear. In this study, we used homologous recombination to construct a double-gene deletion mutant, ΔTAA, in which both TAA coding genes were deleted and used it in in vivo and in vitro studies to confirm that TAAs participate in bacterial auto-aggregation, biofilm formation, cell adhesion and virulence in mice. A microarray analysis was used to determine whether TAAs can regulate other A. pleuropneumoniae genes during interactions with porcine primary alveolar macrophages. The results showed that deletion of both TAA coding genes up-regulated 36 genes, including ene1514, hofB and tbpB2, and simultaneously down-regulated 36 genes, including lgt, murF and ftsY. These data illustrate that TAAs help to maintain full bacterial virulence both directly, through their bioactivity, and indirectly by regulating the bacterial type II and IV secretion systems and regulating the synthesis or secretion of virulence factors. This study not only enhances our understanding of the role of TAAs but also has significance for those studying A. pleuropneumoniae pathogenesis.

Effect of bacterial collagenase on resin-dentin bonds degradation.

PubMed

Toledano, Manuel; Osorio, Raquel; Osorio, Estrella; Aguilera, Fátima S; Yamauti, Monica; Pashley, David H; Tay, Franklin

2007-12-01

The objective of this study is to evaluate the effect of a bacterial collagenase on the degradation of resin-dentin bonds. Human dentin surfaces were bonded with: an etch-&-rinse self-priming adhesive (SB), a two-step self-etching primer/adhesive (SEB), and a 1-step self-etching adhesive (OUB). Composite build-ups were constructed. The bonded teeth were stored (24 h, 3 months, 1 year) in distilled water or in a buffered bacterial collagenase solution. Half of the specimens were stored as intact bonded teeth (Indirect Exposure/IE). The other half were sectioned into beams prior to storage (Direct Exposure/DE). After storage the intact teeth were sectioned into beams and all specimens were tested for microtensile bond strengths (MTBS). ANOVA and multiple comparisons tests were performed. Fractographic analysis was performed by scanning electron microscopy. The inclusion of bacterial collagenase in the storing solution did not lower the MTBS values over those seen in specimens stored in water. SB and SEB bonds strength were equal, and were superior to OUB. After 3 months of DE, SB and OUB bonded specimens showed decreases in MTBS; similar reductions required 1 year for SEB/DE. MTBS did not decrease in IE specimens except for OUB. Resin and collagen dissolution were evident in DE groups after storing.

Effect of oxiplex* films (PEO/CMC) on adhesion formation and reformation in rabbit models and on peritoneal infection in a rat model.

PubMed

Rodgers, K E; Schwartz, H E; Roda, N; Thornton, M; Kobak, W; diZerega, G S

2000-04-01

To assess the efficacy of Oxiplex (FzioMed, Inc., San Luis Obispo, CA) barriers. Film of polyethylene oxide and carboxymethylcellulose (Oxiplex) were tested for strength and tissue adherence. Films were selected for evaluation in models for biocompatability and adherence. Three films were selected for evaluation in efficacy studies, and one was evaluated for effects on bacterial peritonitis. Handling characteristics of Oxiplex film were evaluated via laparoscopy. University laboratory. Rabbits, rats, pigs. Placement of Oxiplex prototypes at the site of injury. Mechanical properties, biocompatibility, tissue adherence, adhesion development, infection potentiation, and device handling. Mechanical tests indicated that tensile strength and elongation were inversely correlated. All films tested had excellent tissue adherence properties. Selected films, based on residence time and biocompatibility, prevented adhesion formation in all animals and were highly efficacious in preventing adhesion reformation. The optimal Oxiplex prototype prevented adhesion reformation in 91% of the animals. This Oxiplex film, dyed to allow visualization, prevented adhesion reformation and did not affect bacterial peritonitis. In a laparoscopic model, the Oxiplex film, delivered in FilmSert forceps, via a 5.0-mm trocar, rapidly unfurled and could be easily applied to tissue with strong adherence. These data show development of an adhesion prevention material that is tissue adherent, can be placed via laparoscopy, and does not affect host resistance.

The Biochemistry and Physiology of Bacterial Adhesion to Surfaces

DTIC Science & Technology

1984-01-20

Organism S was isolated from surfaces incubated 33258 (Calbiochem-Behring Corp.. La Jolla, Calif.) in in an aquarium containing Instant Ocean...Abstiact /The physiologic mechanisms involved in bacterial adhesion to inert surfaces have been Investigated employing fouling isolates obtained from...of Madilyn Fletcher. Environmental Sci- A n l ms ences Department. University of Warwick. Coventry. All organisms isolated from surfaces exposed

Antiadhesion agents against Gram-positive pathogens.

PubMed

Cascioferro, Stella; Cusimano, Maria Grazia; Schillaci, Domenico

2014-01-01

A fundamental step of Gram-positive pathogenesis is the bacterial adhesion to the host tissue involving interaction between bacterial surface molecules and host ligands. This review is focused on antivirulence compounds that target Gram-positive adhesins and on their potential development as therapeutic agents alternative or complementary to conventional antibiotics in the contrast of pathogens. In particular, compounds that target the sortase A, wall theicoic acid inhibitors, carbohydrates able to bind bacterial proteins and proteins capable of influencing the bacterial adhesion, were described. We further discuss the advantages and disadvantages of this strategy in the development of novel antimicrobials and the future perspective of this research field still at its first steps.

Carbohydrate-binding specificities of potential probiotic Lactobacillus strains in porcine jejunal (IPEC-J2) cells and porcine mucin.

PubMed

Valeriano, Valerie Diane; Bagon, Bernadette B; Balolong, Marilen P; Kang, Dae-Kyung

2016-07-01

Bacterial lectins are carbohydrate-binding adhesins that recognize glycoreceptors in the gut mucus and epithelium of hosts. In this study, the contribution of lectin-like activities to adhesion of Lactobacillus mucosae LM1 and Lactobacillus johnsonii PF01, which were isolated from swine intestine, were compared to those of the commercial probiotic Lactobacillus rhamnosus GG. Both LM1 and PF01 strains have been reported to have good adhesion ability to crude intestinal mucus of pigs. To confirm this, we quantified their adhesion to porcine gastric mucin and intestinal porcine enterocytes isolated from the jejunum of piglets (IPEC-J2). In addition, we examined their carbohydrate-binding specificities by suspending bacterial cells in carbohydrate solutions prior to adhesion assays. We found that the selected carbohydrates affected the adherences of LM1 to IPEC-J2 cells and of LGG to mucin. In addition, compared to adhesion to IPEC-J2 cells, adhesion to mucin by both LM1 and LGG was characterized by enhanced specific recognition of glycoreceptor components such as galactose, mannose, and N-acetylglucosamine. Hydrophobic interactions might make a greater contribution to adhesion of PF01. A similar adhesin profile between a probiotic and a pathogen, suggest a correlation between shared pathogen-probiotic glycoreceptor recognition and the ability to exclude enteropathogens such as Escherichia coli K88 and Salmonella Typhimurium KCCM 40253. These findings extend our understanding of the mechanisms of the intestinal adhesion and pathogen-inhibition abilities of probiotic Lactobacillus strains.

An in vitro bacterial adhesion assessment of surface-modified medical-grade PVC.

PubMed

Asadinezhad, Ahmad; Novák, Igor; Lehocký, Marián; Sedlarík, Vladimir; Vesel, Alenka; Junkar, Ita; Sáha, Petr; Chodák, Ivan

2010-06-01

Medical-grade polyvinyl chloride was surface modified by a multistep physicochemical approach to improve bacterial adhesion prevention properties. This was fulfilled via surface activation by diffuse coplanar surface barrier discharge plasma followed by radical graft copolymerization of acrylic acid through surface-initiated pathway to render a structured high density brush. Three known antibacterial agents, bronopol, benzalkonium chloride, and chlorhexidine, were then individually coated onto functionalized surface to induce biological properties. Various modern surface probe techniques were employed to explore the effects of the modification steps. In vitro bacterial adhesion and biofilm formation assay was performed. Escherichia coli strain was found to be more susceptible to modifications rather than Staphylococcus aureus as up to 85% reduction in adherence degree of the former was observed upon treating with above antibacterial agents, while only chlorhexidine could retard the adhesion of the latter by 50%. Also, plasma treated and graft copolymerized samples were remarkably effective to diminish the adherence of E. coli. Copyright 2010 Elsevier B.V. All rights reserved.

Nonimmunoglobulin fraction of human milk inhibits bacterial adhesion (hemagglutination) and enterotoxin binding of Escherichia coli and Vibrio cholerae.

PubMed Central

Holmgren, J; Svennerholm, A M; Ahrén, C

1981-01-01

Human milk and colostrum samples were divided into an immunoglobulin and a nonimmunoglobulin fraction by immunosorbent chromatography. The ability of these fractions to inhibit bacterial cell adhesion and enterotoxin receptor binding of Vibrio cholerae and various Escherichia coli isolates was then tested by in vitro assays. The strongest effect was generally seen with the nonimmunoglobulin fractions, which were shown to significantly inhibit E. coli cell adhesion (hemagglutination) mediated by CFA/I, CFA/II, or K88 fimbriae (but not type 1 pili) and V. cholerae hemagglutination, as well as the binding of cholera toxin and E. coli heat-labile enterotoxin to GM1 ganglioside. Also, the immunoglobulin fractions had significant inhibitory activity in some of these systems. The results are interpreted to suggest that human milk and colostrum may contain secreted structure analogs of the cell receptors for some bacterial adhesions and enterotoxins; this might contribute to the protective effect of milk against enteric infections. PMID:7021421

Inactivation of Lactobacillus rhamnosus GG by fixation modifies its probiotic properties.

PubMed

Markowicz, C; Kubiak, P; Grajek, W; Schmidt, M T

2016-01-01

Probiotics are microorganisms that have beneficial effects on the host and are safe for oral intake in a suitable dose. However, there are situations in which the administration of living microorganisms poses a risk for immunocompromised host. The objective of this study was to evaluate the influence of several fixation methods on selected biological properties of Lactobacillus rhamnosus GG that are relevant to its probiotic action. Fixation of the bacterial cells with ethanol, 2-propanol, glutaraldehyde, paraformaldehyde, and heat treatment resulted in a significant decrease of alkaline phosphatase, peroxidase, and β-galactosidase activities. Most of the fixation procedures reduced bacterial cell hydrophobicity and increased adhesion capacity. The fixation procedures resulted in a different perception of the bacterial cells by enterocytes, which was shown as changes in gene expression in enterocytes. The results show that some procedures of inactivation allow a fraction of the enzymatic activity to be maintained. The adhesion properties of the bacterial cells were enhanced, but the response of enterocytes to fixed cells was different than to live bacteria. Inactivation allows maintenance and modification of some of the properties of the bacterial cells.

Influence of type-I fimbriae and fluid shear stress on bacterial behavior and multicellular architecture of early Escherichia coli biofilms at single-cell resolution.

PubMed

Wang, Liyun; Keatch, Robert; Zhao, Qi; Wright, John A; Bryant, Clare E; Redmann, Anna L; Terentjev, Eugene M

2018-01-12

Biofilm formation on abiotic surfaces in food and medical industry can cause severe contamination and infection, yet how biological and physical factors determine cellular architecture of early biofilms and bacterial behavior of the constituent cells remains largely unknown. In this study we examine the specific role of type-I fimbriae in nascent stages of biofilm formation and the response of micro-colonies to environmental flow shear at single-cell resolution. The results show that type-I fimbriae are not required for reversible adhesion from plankton, but critical for irreversible adhesion of Escherichia coli ( E.coli ) MG1655 forming biofilms on polyethylene terephthalate (PET) surfaces. Besides establishing a firm cell-surface contact, the irreversible adhesion seems necessary to initiate the proliferation of E.coli on the surface. After application of shear stress, bacterial retention is dominated by the 3D architecture of colonies independent of the population and the multi-layered structure could protect the embedded cells from being insulted by fluid shear, while cell membrane permeability mainly depends on the biofilm population and the duration time of the shear stress. Importance Bacterial biofilms could lead to severe contamination problems in medical devices and food processing equipment. However, biofilms are usually studied at a rough macroscopic level, thus little is known about how individual bacterial behavior within biofilms and multicellular architecture are influenced by bacterial appendages (e.g. pili/fimbriae) and environmental factors during early biofilm formation. We apply Confocal Laser Scanning Microscopy (CLSM) to visualize E.coli micro-colonies at single-cell resolution. Our findings suggest that type-I fimbriae are vital to the initiation of bacterial proliferation on surfaces and that the responses of biofilm architecture and cell membrane permeability of constituent bacteria to fluid shear stress are different, which are respectively regulated by the 3D morphology and the population of micro-colonies. Copyright © 2018 American Society for Microbiology.

Silver deposition on titanium surface by electrochemical anodizing process reduces bacterial adhesion of Streptococcus sanguinis and Lactobacillus salivarius.

PubMed

Godoy-Gallardo, Maria; Rodríguez-Hernández, Ana G; Delgado, Luis M; Manero, José M; Javier Gil, F; Rodríguez, Daniel

2015-10-01

The aim of this study was to determine the antibacterial properties of silver-doped titanium surfaces prepared with a novel electrochemical anodizing process. Titanium samples were anodized with a pulsed process in a solution of silver nitrate and sodium thiosulphate at room temperature with stirring. Samples were processed with different electrolyte concentrations and treatment cycles to improve silver deposition. Physicochemical properties were determined by X-ray photoelectron spectroscopy, contact angle measurements, white-light interferometry, and scanning electron microscopy. Cellular cytotoxicity in human fibroblasts was studied with lactate dehydrogenase assays. The in vitro effect of treated surfaces on two oral bacteria strains (Streptococcus sanguinis and Lactobacillus salivarius) was studied with viable bacterial adhesion measurements and growth curve assays. Nonparametric statistical Kruskal-Wallis and Mann-Whitney U-tests were used for multiple and paired comparisons, respectively. Post hoc Spearman's correlation tests were calculated to check the dependence between bacteria adhesion and surface properties. X-ray photoelectron spectroscopy results confirmed the presence of silver on treated samples and showed that treatments with higher silver nitrate concentration and more cycles increased the silver deposition on titanium surface. No negative effects in fibroblast cell viability were detected and a significant reduction on bacterial adhesion in vitro was achieved in silver-treated samples compared with control titanium. Silver deposition on titanium with a novel electrochemical anodizing process produced surfaces with significant antibacterial properties in vitro without negative effects on cell viability. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The adhesion of Pseudomonas aeruginosa to high molecular weight human tear film species corresponds to glycoproteins reactive with Sambucus nigra lectin.

PubMed

Aristoteli, Lina Panayiota; Willcox, Mark D P

2006-11-01

Pseudomonas aeruginosa is a pathogen gaining prevalence in contact lens-related corneal ulcers. Tear outflow protects the ocular surface, where high molecular weight tear glycoproteins bind bacteria for removal from the eye. The purpose of the present study was to identify glycoproteins in human tears involved in the adhesion of ocular P. aeruginosa isolates. Basal human tears were applied to a bacterial adhesion assay involving electrophoretic separation of tear components, transfer to nitrocellulose and incubation with biotin-labelled bacteria. Glycoproteins were further characterised using lectin profiling. The results showed large-dimension agarose gels were imperative for the detection of at least four glycoproteins with a migration >200 kDa, including species not previously identified. P. aeruginosa 6294 preferentially bound to a well-defined glycoprotein near the origin of the gel that, unlike other glycoproteins >200 kDa, reacted with Sambucus nigra lectin (sialic acid alpha2-6) but not WGA lectin (N-acetylglucosamine, sialic acid alpha2-3). Adhesion did not involve free biotin label or hydrophobic interactions. Also, the pre-incubation of separated tear glycoproteins with S. nigra lectin increased subsequent adhesion of 6294 to this tear glycoprotein. The less virulent Paer1 strain showed diffuse adhesion in the S. nigra-reactive region at the gel origin. In conclusion, an overlay adhesion assay was developed that identified slow-migrating sialylated glycoprotein species in human tears preferentially bound by P. aeruginosa ocular strains, and S. nigra lectin seemed to enhance the interaction. The study provides a basis for direct investigation of bacterial adhesion to glycoproteins with an apparent migration >200 kDa in tear fluid.

The ancillary protein 1 of Streptococcus pyogenes FCT-1 pili mediates cell adhesion and biofilm formation through heterophilic as well as homophilic interactions

PubMed Central

Becherelli, Marco; Manetti, Andrea G O; Buccato, Scilla; Viciani, Elisa; Ciucchi, Laura; Mollica, Giulia; Grandi, Guido; Margarit, Imma

2012-01-01

Summary Gram-positive pili are known to play a role in bacterial adhesion to epithelial cells and in the formation of biofilm microbial communities. In the present study we undertook the functional characterization of the pilus ancillary protein 1 (AP1_M6) from Streptococcus pyogenes isolates expressing the FCT-1 pilus variant, known to be strong biofilm formers. Cell binding and biofilm formation assays using S. pyogenes in-frame deletion mutants, Lactococcus expressing heterologous FCT-1 pili and purified recombinant AP1_M6, indicated that this pilin is a strong cell adhesin that is also involved in bacterial biofilm formation. Moreover, we show that AP1_M6 establishes homophilic interactions that mediate inter-bacterial contact, possibly promoting bacterial colonization of target epithelial cells in the form of three-dimensional microcolonies. Finally, AP1_M6 knockout mutants were less virulent in mice, indicating that this protein is also implicated in GAS systemic infection. PMID:22320452

Nucleation of platelets with blood-borne pathogens on Kupffer cells precedes other innate immunity and contributes to bacterial clearance.

PubMed

Wong, Connie H Y; Jenne, Craig N; Petri, Björn; Chrobok, Navina L; Kubes, Paul

2013-08-01

Through the use of intravital imaging of the liver, we demonstrate a collaborative role for platelets with Kupffer cells (KCs) in eradicating blood-borne bacterial infection. Under basal conditions, platelets, via the platelet-adhesion receptor GPIb, formed transient 'touch-and-go' interactions with von Willebrand factor (vWF) constitutively expressed on KCs. Bacteria such as Bacillus cereus and methicillin-resistant Staphylococcus aureus (MRSA) were rapidly caught by KCs and triggered platelets to switch from 'touch-and-go' adhesion to sustained GPIIb-mediated adhesion on the KC surface to encase the bacterium. Infected GPIbα-deficient mice had more endothelial and KC damage than did their wild-type counterparts, which led to more fluid leakage, substantial polycythemia and rapid mortality. Our study identifies a previously unknown surveillance mechanism by which platelets survey macrophages that rapidly converts to a critical host response to blood-borne bacteria.

Inhibition of P-fimbriated Escherichia coli adhesion by multivalent galabiose derivatives studied by a live-bacteria application of surface plasmon resonance.

PubMed

Salminen, Annika; Loimaranta, Vuokko; Joosten, John A F; Khan, A Salam; Hacker, Jörg; Pieters, Roland J; Finne, Jukka

2007-09-01

Uropathogenic P-fimbriated Escherichia coli adheres to host cells by specific adhesins recognizing galabiose (Galalpha1-4Gal)-containing structures on cell surfaces. In search of agents inhibiting this first step of infection, the inhibition potency of a set of synthetic mono- and multivalent galabiose compounds was evaluated. In order to mimic the flow conditions of natural infections, a live-bacteria application of surface plasmon resonance (SPR) was established. For the measurement of the binding of E. coli to a surface containing galabiose, live bacteria were injected over the flow cell, and the inhibition of adhesion caused by the galabiose inhibitors was recorded. Quantitative binding data were recorded in real-time for each inhibitor. The results were compared with those of conventional static haemagglutination and ELISA-based cell adhesion assays. Compared with the Gram-positive Streptococcus suis bacteria, which also bind to galabiose and whose binding inhibition is strongly dependent on the multivalency of the inhibitor, E. coli inhibition was only moderately affected by the valency. However, a novel octavalent compound was found to be the most effective inhibitor of E. coli PapG(J96) adhesion, with an IC50 value of 2 microM. Measurement of bacterial adhesion by SPR is an efficient way to characterize the adhesion of whole bacterial cells and allows the characterization of the inhibitory potency of adhesion inhibitors under dynamic flow conditions. Under these conditions, multivalency increases the anti-adhesion potency of galabiose-based inhibitors of P-fimbriated E. coli adhesion and provides a promising approach for the design of high-affinity anti-adhesion agents.

Mechanical, In Vitro Antimicrobial and Biological Properties of Plasma Sprayed Silver-Doped Hydroxyapatite Coating

PubMed Central

Roy, Mangal; Fielding, Gary A.; Beyenal, Haluk; Bandyopadhyay, Amit; Bose, Susmita

2012-01-01

Implant related infection is one of the key concerns in total joint hip arthroplasties. In order to reduce bacterial adhesion, silver (Ag) / silver oxide (Ag2O) doping was used in plasma sprayed hydroxyapatite (HA) coating on titanium substrate. HA powder was doped with 2.0, 4.0 and 6.0 wt% Ag, heat treated at 800 °C and used for plasma spray coating using a 30 kW plasma spray system, equipped with supersonic nozzle. Application of supersonic plasma nozzle significantly reduced phase decomposition and amorphous phase formation in the HA coatings as evident by X-ray diffraction (XRD) study and Fourier transformed infrared spectroscopic (FTIR) analysis. Adhesive bond strength of more than 15 MPa ensured the mechanical integrity of the coatings. Resistance against bacterial adhesion of the coatings was determined by challenging them against Pseudomonas Aeruginosa (PAO1). Live/Dead staining of the adherent bacteria on the coating surfaces indicated a significant reduction in bacterial adhesion due to the presence of Ag. In vitro cell-material interactions and alkaline phosphatase (ALP) protein expressions were evaluated by culturing human fetal osteoblast cells (hFOB). Present results suggest that the plasma sprayed HA coatings doped with an optimum amount of Ag can have excellent antimicrobial property without altering mechanical property of the Ag doped HA coatings. PMID:22313742

Mechanical, in vitro antimicrobial, and biological properties of plasma-sprayed silver-doped hydroxyapatite coating.

PubMed

Roy, Mangal; Fielding, Gary A; Beyenal, Haluk; Bandyopadhyay, Amit; Bose, Susmita

2012-03-01

Implant-related infection is one of the key concerns in total joint hip arthroplasties. To reduce bacterial adhesion, we used silver (Ag)/silver oxide (Ag(2)O) doping in plasma sprayed hydroxyapatite (HA) coating on titanium substrate. HA powder was doped with 2.0, 4.0, and 6.0 wt % Ag, heat-treated at 800 °C and used for plasma spray coating using a 30 kW plasma spray system, equipped with supersonic nozzle. Application of supersonic plasma nozzle significantly reduced phase decomposition and amorphous phase formation in the HA coatings as evident by X-ray diffraction (XRD) study and Fourier transformed infrared spectroscopic (FTIR) analysis. Adhesive bond strength of more than 15 MPa ensured the mechanical integrity of the coatings. Resistance against bacterial adhesion of the coatings was determined by challenging them against Pseudomonas aeruginosa (PAO1). Live/dead staining of the adherent bacteria on the coating surfaces indicated a significant reduction in bacterial adhesion due to the presence of Ag. In vitro cell-material interactions and alkaline phosphatase (ALP) protein expressions were evaluated by culturing human fetal osteoblast cells (hFOB). Our results suggest that the plasma-sprayed HA coatings doped with an optimum amount of Ag can have excellent antimicrobial property without altering mechanical property of the Ag-doped HA coatings. © 2012 American Chemical Society

Material- and feature-dependent effects on cell adhesion to micro injection moulded medical polymers.

PubMed

Choi, Seong Ying; Habimana, Olivier; Flood, Peter; Reynaud, Emmanuel G; Rodriguez, Brian J; Zhang, Nan; Casey, Eoin; Gilchrist, Michael D

2016-09-01

Two polymers, polymethylmethacrylate (PMMA) and cyclic olefin copolymer (COC), containing a range of nano- to micron- roughness surfaces (Ra 0.01, 0.1, 0.4, 1.0, 2.0, 3.2 and 5.0μm) were fabricated using electrical discharge machining (EDM) and replicated using micro injection moulding (μIM). Polymer samples were characterized using optical profilometry, atomic force microscopy (AFM) and water surface contact angle. Cell adhesion tests were carried out using bacterial Pseudomonas fluorescens and mammalian Madin-Darby Canine Kidney (MDCK) cells to determine the effect of surface hydrophobicity, surface roughness and stiffness. It is found that there are features which gave insignificant differences (feature-dependent effect) in cell adhesion, albeit a significant difference in the physicochemical properties (material-dependent effect) of substrata. In bacterial cell adhesion, the strongest feature-dependence is found at Ra 0.4μm surfaces, with material-dependent effects strongest at Ra 0.01μm. Ra 0.1μm surfaces exhibited strongest feature-dependent effects and Ra 5.0μm has strongest material-dependent effects on mammalian cell adhesion. Bacterial cell adhesion is found to be favourable to hydrophobic surfaces (COC), with the lowest adhesion at Ra 0.4μm for both materials. Mammalian cell adhesion is lowest in Ra 0.1μm and highest in Ra 1.0μm, and generally favours hydrophilic surfaces (PMMA). These findings can be used as a basis for developing medical implants or microfluidic devices using micro injection moulding for diagnostic purposes, by tuning the cell adhesion on different areas containing different surface roughnesses on the diagnostic microfluidic devices or medical implants. Copyright © 2016 Elsevier B.V. All rights reserved.

Preferential adhesion of surface groups of Bacillus subtilis on gibbsite at different ionic strengths and pHs revealed by ATR-FTIR spectroscopy.

PubMed

Hong, Zhi-Neng; Jiang, Jun; Li, Jiu-Yu; Xu, Ren-Kou

2018-05-01

Adhesion of bacteria onto minerals is a ubiquitous process that plays a central role in many biogeochemical, microbiology and environmental processes in soil and sediment. Although bacterial adhesion onto soil minerals such as phyllosilicates and Fe-oxides have been investigated extensively, little is known about the mechanisms for bacterial attachment onto Al-oxides. Here, we explored the adhesion of Bacillus subtilis onto gibbsite (γ-AlOOH) under various ionic strengths (1, 10, 50, and 100 mM NaCl) and pHs (pH 4, 7, and 9) by in-situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The time evolution of the peak intensities of the attached bacteria suggested that the adhesion underwent an initial rapid reaction followed by a slow pseudo-first-order kinetic stage. Spectral comparison between the attached and free cells, together with the interaction energy calculated with the Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory and the micro-morphology of bacteria-gibbsite complexes, indicated that both electrostatic and chemical (bacterial groups such as phosphate and carboxyl covalently bind to gibbsite) interactions participated in the adhesion processes. Both solution ionic strength (IS) and pH impacted the spectra of attached bacteria, but the peak intensity of different bands changed differently with these two factors, showing a preferential adhesion of surface groups (phosphate, carboxyl, and amide groups) on gibbsite at different conditions. The diverse responses to IS and pH alteration of the forces (chemical bonds, electrostatic attractions, and the hydrophobic interactions) that essentially govern the adhesion might be responsible for the preferential adhesion. These results may help to better understand how bacteria adhere onto soil oxides at molecular scales. Copyright © 2018 Elsevier B.V. All rights reserved.

Single-Cell Force Spectroscopy of Probiotic Bacteria

PubMed Central

Beaussart, Audrey; El-Kirat-Chatel, Sofiane; Herman, Philippe; Alsteens, David; Mahillon, Jacques; Hols, Pascal; Dufrêne, Yves F.

2013-01-01

Single-cell force spectroscopy is a powerful atomic force microscopy modality in which a single living cell is attached to the atomic force microscopy cantilever to quantify the forces that drive cell-cell and cell-substrate interactions. Although various single-cell force spectroscopy protocols are well established for animal cells, application of the method to individual bacterial cells remains challenging, mainly owing to the lack of appropriate methods for the controlled attachment of single live cells on cantilevers. We present a nondestructive protocol for single-bacterial cell force spectroscopy, which combines the use of colloidal probe cantilevers and of a bioinspired polydopamine wet adhesive. Living cells from the probiotic species Lactobacillus plantarum are picked up with a polydopamine-coated colloidal probe, enabling us to quantify the adhesion forces between single bacteria and biotic (lectin monolayer) or abiotic (hydrophobic monolayer) surfaces. These minimally invasive single-cell experiments provide novel, to our knowledge, insight into the specific and nonspecific forces driving the adhesion of L. plantarum, and represent a generic platform for studying the molecular mechanisms of cell adhesion in probiotic and pathogenic bacteria. PMID:23663831

Identification of New Factors Modulating Adhesion Abilities of the Pioneer Commensal Bacterium Streptococcus salivarius

PubMed Central

Couvigny, Benoit; Kulakauskas, Saulius; Pons, Nicolas; Quinquis, Benoit; Abraham, Anne-Laure; Meylheuc, Thierry; Delorme, Christine; Renault, Pierre; Briandet, Romain; Lapaque, Nicolas; Guédon, Eric

2018-01-01

Biofilm formation is crucial for bacterial community development and host colonization by Streptococcus salivarius, a pioneer colonizer and commensal bacterium of the human gastrointestinal tract. This ability to form biofilms depends on bacterial adhesion to host surfaces, and on the intercellular aggregation contributing to biofilm cohesiveness. Many S. salivarius isolates auto-aggregate, an adhesion process mediated by cell surface proteins. To gain an insight into the genetic factors of S. salivarius that dictate host adhesion and biofilm formation, we developed a screening method, based on the differential sedimentation of bacteria in semi-liquid conditions according to their auto-aggregation capacity, which allowed us to identify twelve mutations affecting this auto-aggregation phenotype. Mutations targeted genes encoding (i) extracellular components, including the CshA surface-exposed protein, the extracellular BglB glucan-binding protein, the GtfE, GtfG and GtfH glycosyltransferases and enzymes responsible for synthesis of cell wall polysaccharides (CwpB, CwpK), (ii) proteins responsible for the extracellular localization of proteins, such as structural components of the accessory SecA2Y2 system (Asp1, Asp2, SecA2) and the SrtA sortase, and (iii) the LiaR transcriptional response regulator. These mutations also influenced biofilm architecture, revealing that similar cell-to-cell interactions govern assembly of auto-aggregates and biofilm formation. We found that BglB, CshA, GtfH and LiaR were specifically associated with bacterial auto-aggregation, whereas Asp1, Asp2, CwpB, CwpK, GtfE, GtfG, SecA2 and SrtA also contributed to adhesion to host cells and host-derived components, or to interactions with the human pathogen Fusobacterium nucleatum. Our study demonstrates that our screening method could also be used to identify genes implicated in the bacterial interactions of pathogens or probiotics, for which aggregation is either a virulence trait or an advantageous feature, respectively. PMID:29515553

Single-cell force spectroscopy of pili-mediated adhesion

NASA Astrophysics Data System (ADS)

Sullan, Ruby May A.; Beaussart, Audrey; Tripathi, Prachi; Derclaye, Sylvie; El-Kirat-Chatel, Sofiane; Li, James K.; Schneider, Yves-Jacques; Vanderleyden, Jos; Lebeer, Sarah; Dufrêne, Yves F.

2013-12-01

Although bacterial pili are known to mediate cell adhesion to a variety of substrates, the molecular interactions behind this process are poorly understood. We report the direct measurement of the forces guiding pili-mediated adhesion, focusing on the medically important probiotic bacterium Lactobacillus rhamnosus GG (LGG). Using non-invasive single-cell force spectroscopy (SCFS), we quantify the adhesion forces between individual bacteria and biotic (mucin, intestinal cells) or abiotic (hydrophobic monolayers) surfaces. On hydrophobic surfaces, bacterial pili strengthen adhesion through remarkable nanospring properties, which - presumably - enable the bacteria to resist high shear forces under physiological conditions. On mucin, nanosprings are more frequent and adhesion forces larger, reflecting the influence of specific pili-mucin bonds. Interestingly, these mechanical responses are no longer observed on human intestinal Caco-2 cells. Rather, force curves exhibit constant force plateaus with extended ruptures reflecting the extraction of membrane nanotethers. These single-cell analyses provide novel insights into the molecular mechanisms by which piliated bacteria colonize surfaces (nanosprings, nanotethers), and offer exciting avenues in nanomedicine for understanding and controlling the adhesion of microbial cells (probiotics, pathogens).

Administration of honey to prevent peritoneal adhesions in a rat peritonitis model.

PubMed

Yuzbasioglu, Mehmet Fatih; Kurutas, Ergul Belge; Bulbuloglu, Ertan; Goksu, Mustafa; Atli, Yalcin; Bakan, Vedat; Kale, Ilhami Taner

2009-02-01

We investigated the effects of intraperitoneal honey on the development of postoperative intra-abdominal adhesions and oxidative stress in a model of bacterial peritonitis. Bacterial peritonitis was induced in 18 rats by cecal ligation and puncture. The rats were randomly assigned to three groups. Group 1 (n=6) received honey intraperitoneally, group 2 (n=6) received 5% dextrose intraperitoneally, and the third group received no fluid or medicine intraperitoneally one day after cecal ligation and puncture procedure. All animals were killed 14 days later so we could assess the adhesion score. Tissue antioxidant levels were measured in 1-g tissue samples taken from the abdominal wall. Adhesion scores of honey treated group were significantly lower according to the control group (P<0.05) and statistically significant. Adhesion scores of honey were lower from 5% dextrose but not statistically significant (P>0.05). Malondialdehyde values of honey group were significantly lower from the control group (P<0.05) and levels in 5% dextrose group was higher than the honey group. Catalase levels were high in control and 5% dextrose groups. Superoxide dismutase levels were higher in the control group than the honey group (statistically significant). Intraperitoneal honey decreased the formation of postoperative intra-abdominal adhesions without compromising wound healing in this bacterial peritonitis rat model. Honey also decreased the oxidative stress during peritonitis.

In vitro study of antibiotic effect on bacterial adherence to acrylic intraocular lenses.

PubMed

Gaál, Valéria; Kilár, Ferenc; Acs, Barnabás; Szijjártó, Zsuzsanna; Kocsis, Béla; Kustos, Ildikó

2005-11-10

Implantation of artificial intraocular lenses into the eye during ophthalmic surgical procedures ensures an unliving surface on which bacterial pathogens may attach and form biofilms. Despite antibiotic treatment bacteria growing in biofilms might cause inflammation and serious complications. In this study the adhesive ability of 7 Staphylococcus aureus and 11 coagulase-negative Staphylococcus (CNS) strains to the surface of acrylic intraocular lenses had been examined by the ultrasonic method. In untreated cases adhesion of the S. aureus and CNS strains did not differ significantly. We could not demonstrate significant differences between the adhesive ability of the standard strains and the clinical isolates. In this study a single--60 min long--antibiotic (ciprofloxacin and tobramycin) treatment had been applied, that correlate well with the single or intermittant antibiotic prophylaxis of patients. Ciprofloxacin administration was able to reduce significantly the number of attached cells on the surface of acrylic lenses both in the case of S. aureus and CNS strains. Dependence of the effect from concentration could also be demonstrated. Tobramycin treatment was able to inhibit significantly the attachment of S. aureus cells. Despite the debate on antibiotic prophylaxis we presented in our experiments that a single antibiotic administration can decrease the attachment of bacterial cells to the surface of acrylic intraocular lenses, and might be effective in the prevention of postoperative endophthalmitis, that is a rare but serious complication of ophthalmic surgery.

Comparison of bacterial attachment to platelet bags with and without preconditioning with plasma.

PubMed

Loza-Correa, M; Kalab, M; Yi, Q-L; Eltringham-Smith, L J; Sheffield, W P; Ramirez-Arcos, S

2017-07-01

Canadian Blood Services produces apheresis and buffy coat pooled platelet concentrates (PCs) stored in bags produced by two different manufacturers (A and B, respectively), both made of polyvinyl chloride-butyryl trihexyl citrate. This study was aimed at comparing Staphylococcus epidermidis adhesion to the inner surface of both bag types in the presence or absence of plasma factors. Sets (N = 2-6) of bags type A and B were left non-coated (control) or preconditioned with platelet-rich, platelet-poor or defibrinated plasma (PRP, PPP and DefibPPP, respectively). Each bag was inoculated with a 200-ml S. epidermidis culture adjusted to 0·5 colony-forming units/ml. Bags were incubated under platelet storage conditions for 7 days. After culture removal, bacteria attached to the plastic surface were either dislodged by sonication for bacterial quantification or examined in situ by scanning electron microscopy (SEM). Higher bacterial adhesion was observed to preconditioned PC bags than control containers for both bag types (P < 0·0001). Bacterial attachment to preconditioned bags was confirmed by SEM. Bacteria adhered equally to both types of containers in the presence of PRP, PPP and DefibPPP residues (P > 0·05). By contrast, a significant increase in bacterial adherence was observed to type A bags compared with type B bags in the absence of plasma (P < 0·05) [Correction added on 16 June 2017, after first online publication: this sentence has been corrected]. The ability of S. epidermidis to adhere to preconditioned platelet collection bags depends on the presence of plasma factors. Future efforts should be focused on reducing plasma proteins' attachment to platelet storage containers to decrease subsequent bacterial adhesion. © 2017 International Society of Blood Transfusion.

Proteinaceous determinants of surface colonization in bacteria: bacterial adhesion and biofilm formation from a protein secretion perspective

PubMed Central

Chagnot, Caroline; Zorgani, Mohamed A.; Astruc, Thierry; Desvaux, Mickaël

2013-01-01

Bacterial colonization of biotic or abiotic surfaces results from two quite distinct physiological processes, namely bacterial adhesion and biofilm formation. Broadly speaking, a biofilm is defined as the sessile development of microbial cells. Biofilm formation arises following bacterial adhesion but not all single bacterial cells adhering reversibly or irreversibly engage inexorably into a sessile mode of growth. Among molecular determinants promoting bacterial colonization, surface proteins are the most functionally diverse active components. To be present on the bacterial cell surface, though, a protein must be secreted in the first place. Considering the close association of secreted proteins with their cognate secretion systems, the secretome (which refers both to the secretion systems and their protein substrates) is a key concept to apprehend the protein secretion and related physiological functions. The protein secretion systems are here considered in light of the differences in the cell-envelope architecture between diderm-LPS (archetypal Gram-negative), monoderm (archetypal Gram-positive) and diderm-mycolate (archetypal acid-fast) bacteria. Besides, their cognate secreted proteins engaged in the bacterial colonization process are regarded from single protein to supramolecular protein structure as well as the non-classical protein secretion. This state-of-the-art on the complement of the secretome (the secretion systems and their cognate effectors) involved in the surface colonization process in diderm-LPS and monoderm bacteria paves the way for future research directions in the field. PMID:24133488

Bacterial Adhesion of Streptococcus suis to Host Cells and Its Inhibition by Carbohydrate Ligands

PubMed Central

Kouki, Annika; Pieters, Roland J.; Nilsson, Ulf J.; Loimaranta, Vuokko; Finne, Jukka; Haataja, Sauli

2013-01-01

Streptococcus suis is a Gram-positive bacterium, which causes sepsis and meningitis in pigs and humans. This review examines the role of known S. suis virulence factors in adhesion and S. suis carbohydrate-based adhesion mechanisms, as well as the inhibition of S. suis adhesion by anti-adhesion compounds in in vitro assays. Carbohydrate-binding specificities of S. suis have been identified, and these studies have shown that many strains recognize Galα1-4Gal-containing oligosaccharides present in host glycolipids. In the era of increasing antibiotic resistance, new means to treat infections are needed. Since microbial adhesion to carbohydrates is important to establish disease, compounds blocking adhesion could be an alternative to antibiotics. The use of oligosaccharides as drugs is generally hampered by their relatively low affinity (micromolar) to compete with multivalent binding to host receptors. However, screening of a library of chemically modified Galα1-4Gal derivatives has identified compounds that inhibit S. suis adhesion in nanomolar range. Also, design of multivalent Galα1-4Gal-containing dendrimers has resulted in a significant increase of the inhibitory potency of the disaccharide. The S. suis adhesin binding to Galα1-4Gal-oligosaccharides, Streptococcal adhesin P (SadP), was recently identified. It has a Galα1-4Gal-binding N-terminal domain and a C-terminal LPNTG-motif for cell wall anchoring. The carbohydrate-binding domain has no homology to E. coli P fimbrial adhesin, which suggests that these Gram-positive and Gram-negative bacterial adhesins recognizing the same receptor have evolved by convergent evolution. SadP adhesin may represent a promising target for the design of anti-adhesion ligands for the prevention and treatment of S. suis infections. PMID:24833053

Comparison of surface roughness and bacterial adhesion between cosmetic contact lenses and conventional contact lenses.

PubMed

Ji, Yong Woo; Cho, Young Joo; Lee, Chul Hee; Hong, Soon Ho; Chung, Dong Yong; Kim, Eung Kweon; Lee, Hyung Keun

2015-01-01

To compare physical characteristics of cosmetic contact lenses (Cos-CLs) and conventional contact lenses (Con-CLs) that might affect susceptibility to bacterial adhesion on the contact lens (CL) surface. Surface characteristics of Cos-CLs and Con-CLs made from the same material by the same manufacturer were measured by atomic force microscopy (AFM) and scanning electron microscopy. To determine the extent and rate of bacterial adhesion, Cos-CL and Con-CL were immersed in serum-free Roswell Park Memorial Institute media containing Staphylococcus aureus or Pseudomonas aeruginosa. Additionally, the rate of removal of adherent bacteria was evaluated using hand rubbing or immersion in multipurpose disinfecting solutions (MPDS). The mean surface roughness (root mean square and peak-to-valley value) measured by AFM was significantly higher for Cos-CL than for Con-CL. At each time point, significantly more S. aureus and P. aeruginosa adhered to Cos-CL than to Con-CL, which correlated with the surface roughness of CL. In Cos-CL, bacteria were mainly found on the tinted surface rather than on the noncolored or convex areas. Pseudomonas aeruginosa attached earlier than S. aureus to all types of CL. However, P. aeruginosa was more easily removed from the surface of CL than S. aureus by hand rubbing or MPDS soaking. Increased surface roughness is an important physical factor for bacterial adhesion in Cos-CL, which may explain why rates of bacterial keratitis rates are higher in Cos-CL users in CL physical characteristics.

Femtosecond laser induced surface modification for prevention of bacterial adhesion on 45S5 bioactive glass

NASA Astrophysics Data System (ADS)

Shaikh, Shazia; Singh, Deepti; Subramanian, Mahesh; Kedia, Sunita; Singh, Anil Kumar; Singh, Kulwant; Gupta, Nidhi; Sinha, Sucharita

2018-02-01

Bacterial attachment and biofilm formation on implant surface has been a major concern in hospital and industrial environment. Prevention of bacterial infections of implant surface through surface treatment could be a potential solution and hence this has become a key area of research. In the present study, the antibacterial and biocompatible properties of femtosecond laser surface treated 45S5 bioactive glass (BG) have been investigated. Adhesion and sustainability of both gram positive S. aureus and gram negative P.aeruginosa and E. coli nosocomial bacteria on untreated and laser treated BG samples has been explored. An imprint method has been used to visualize the growth of bacteria on the sample surface. We observed complete bacterial rejection potentially reducing risk of biofilm formation on laser treated surface. This was correlated with surface roughness, wettability and change in surface chemical composition of the samples before and after laser treatment. Biocompatibility of the laser treated BG was demonstrated by studying the anchoring and growth of human cervix cell line INT407. Our results demonstrate that, laser surface modification of BG enables enhanced bacterial rejection without affecting its biocompatibility towards growth of human cells on it. These results open a significantly potential approach towards use of laser in successfully imparting desirable characteristics to BG based bio-implants and devices.

Demonstration of nitric oxide synthase activity in crustacean hemocytes and anti-microbial activity of hemocyte-derived nitric oxide.

PubMed

Yeh, Feng-Ching; Wu, Su-Hua; Lai, Chi-Yung; Lee, Chi-Ying

2006-05-01

We determined the biochemical characteristics of nitric oxide synthase (NOS) in hemocytes of the crayfish Procambarus clarkii and investigated the roles of hemocyte-derived NO in host defense. Biochemical analysis indicated the presence of a Ca2+ -independent NOS activity, which was elevated by lipopolysaccharide (LPS) treatment. When bacteria (Staphylococcus aureus) and hemocytes were co-incubated, adhesion of bacteria to hemocytes was observed. NO donor sodium nitroprusside (SNP) significantly increased the numbers of hemocytes to which bacteria adhered. Similarly, LPS elicited bacterial adhesion and the LPS-induced adhesion was prevented by NOS inhibitor NG-monomethyl-L-arginine (L-NMMA). Finally, plate count assay demonstrated that addition of LPS to the hemocytes/bacteria co-incubation resulted in a significant decrease in bacterial colony forming unit (CFU), and that L-NMMA reversed the decreasing effect of LPS on CFU. The combined results demonstrate the presence of a Ca2+ -independent LPS-inducible NOS activity in crayfish hemocytes and suggest that hemocyte-derived NO is involved in promoting bacterial adhesion to hemocytes and enhancing bactericidal activity of hemocytes.

Mucin- and carbohydrate-stimulated adhesion and subproteome changes of the probiotic bacterium Lactobacillus acidophilus NCFM.

PubMed

Celebioglu, Hasan Ufuk; Olesen, Sita Vaag; Prehn, Kennie; Lahtinen, Sampo J; Brix, Susanne; Abou Hachem, Maher; Svensson, Birte

2017-06-23

Adhesion to intestinal mucosa is a crucial property for probiotic bacteria. Adhesion is thought to increase host-bacterial interactions, thus potentially enabling health benefits to the host. Molecular events connected with adhesion and surface proteome changes were investigated for the probiotic Lactobacillus acidophilus NCFM cultured with established or emerging prebiotic carbohydrates as carbon source and in the presence of mucin, the glycoprotein of the epithelial mucus layer. Variation in adhesion to HT29-cells and mucin was associated with carbon source and mucin-induced subproteome abundancy differences. Specifically, while growth on fructooligosaccharides (FOS) only stimulated adhesion to intestinal HT-29 cells, cellobiose and polydextrose in addition increased adhesion to mucin. Adhesion to HT-29 cells increased by about 2-fold for bacteria grown on mucin-supplemented glucose. Comparative 2DE-MS surface proteome analysis showed different proteins in energy metabolism appearing on the surface, suggesting they exert moonlighting functions. Mucin-supplemented bacteria had relative abundance of pyruvate kinase and fructose-bisphosphate aldolase increased by about 2-fold while six spots with 3.2-2.1 fold reduced relative abundance comprised elongation factor G, phosphoglycerate kinase, BipAEFTU family GTP-binding protein, ribonucleoside triphosphate reductase, adenylosuccinate synthetase, 30S ribosomal protein S1, and manganese-dependent inorganic pyrophosphatase. Surface proteome of cellobiose- compared to glucose-grown L. acidophilus NCFM had phosphate starvation inducible protein stress-related, thermostable pullulanase, and elongation factor G increasing 4.4-2.4 fold, while GAPDH, elongation factor Ts, and pyruvate kinase were reduced by 2.0-1.5 fold in relative abundance. Addition of recombinant L. acidophilus NCFM elongation factor G and pyruvate kinase to a coated mucin layer significantly suppressed subsequent adhesion of the bacterium. Human diet is important for intestinal health and food components, especially non-digestible carbohydrates can beneficially modify the microbiota. In the present study, effects of emerging and established prebiotic carbohydrates on the probiotic potential of Lactobacillus acidophilus NCFM were investigated by testing adhesion to a mucin layer and intestinal cells, and comparing this with changes in abundancy of surface proteins thought to be important for host interactions. Increased adhesion was observed following culturing of the bacterium with fructooligosaccharides, cellobiose or polydextrose, as well as mucin-supplemented glucose as carbon source. Enhanced adhesion ability can prolong bacterial residence in GIT yielding positive health effects. Higher relative abundance of certain surface proteins under various conditions (i.e. grown on cellobiose or mucin-supplemented glucose) suggested involvement of these proteins in adhesion, as confirmed by competition in case of two recombinantly produced moonlighting proteins. Combination of Lactobacillus acidophilus NCFM with different carbohydrates revealed potential bacterial determinants of synbiotic interactions, including stimulation of adhesion. Copyright © 2017 Elsevier B.V. All rights reserved.

Localization of adhesins on the surface of a pathogenic bacterial envelope through atomic force microscopy

NASA Astrophysics Data System (ADS)

Arnal, L.; Longo, G.; Stupar, P.; Castez, M. F.; Cattelan, N.; Salvarezza, R. C.; Yantorno, O. M.; Kasas, S.; Vela, M. E.

2015-10-01

Bacterial adhesion is the first and a significant step in establishing infection. This adhesion normally occurs in the presence of flow of fluids. Therefore, bacterial adhesins must be able to provide high strength interactions with their target surface in order to maintain the adhered bacteria under hydromechanical stressing conditions. In the case of B. pertussis, a Gram-negative bacterium responsible for pertussis, a highly contagious human respiratory tract infection, an important protein participating in the adhesion process is a 220 kDa adhesin named filamentous haemagglutinin (FHA), an outer membrane and also secreted protein that contains recognition domains to adhere to ciliated respiratory epithelial cells and macrophages. In this work, we obtained information on the cell-surface localization and distribution of the B. pertussis adhesin FHA using an antibody-functionalized AFM tip. Through the analysis of specific molecular recognition events we built a map of the spatial distribution of the adhesin which revealed a non-homogeneous pattern. Moreover, our experiments showed a force induced reorganization of the adhesin on the surface of the cells, which could explain a reinforced adhesive response under external forces. This single-molecule information contributes to the understanding of basic molecular mechanisms used by bacterial pathogens to cause infectious disease and to gain insights into the structural features by which adhesins can act as force sensors under mechanical shear conditions.Bacterial adhesion is the first and a significant step in establishing infection. This adhesion normally occurs in the presence of flow of fluids. Therefore, bacterial adhesins must be able to provide high strength interactions with their target surface in order to maintain the adhered bacteria under hydromechanical stressing conditions. In the case of B. pertussis, a Gram-negative bacterium responsible for pertussis, a highly contagious human respiratory tract infection, an important protein participating in the adhesion process is a 220 kDa adhesin named filamentous haemagglutinin (FHA), an outer membrane and also secreted protein that contains recognition domains to adhere to ciliated respiratory epithelial cells and macrophages. In this work, we obtained information on the cell-surface localization and distribution of the B. pertussis adhesin FHA using an antibody-functionalized AFM tip. Through the analysis of specific molecular recognition events we built a map of the spatial distribution of the adhesin which revealed a non-homogeneous pattern. Moreover, our experiments showed a force induced reorganization of the adhesin on the surface of the cells, which could explain a reinforced adhesive response under external forces. This single-molecule information contributes to the understanding of basic molecular mechanisms used by bacterial pathogens to cause infectious disease and to gain insights into the structural features by which adhesins can act as force sensors under mechanical shear conditions. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04644k

Antimicrobial, antiadhesive and antibiofilm activity of an ethanolic, anthocyanin-rich blueberry extract purified by solid phase extraction.

PubMed

Silva, S; Costa, E M; Mendes, M; Morais, R M; Calhau, C; Pintado, M M

2016-09-01

The present work aimed to characterize the impact of an anthocyanin-rich blueberry extract upon the growth, adhesion and biofilm formation of several pathogens including some multiresistant bacteria. A group comprised of reference strains and clinical multiresistant isolates of Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Acinetobacter baumannii and Staphylococcus aureus, were used to screen for antimicrobial activity. Microbial growth was determined through the measurement of the optical density while adhesion and biofilm formation was determined using the standard crystal violet staining procedure. The results showed that, while blueberry extract was only effective in hindering the growth of Staph. aureus and E. coli, it was capable of significantly inhibiting biofilm formation and bacterial adhesion for all micro-organisms tested. The extract demonstrated a considerable potential as a natural, alternative antimicrobial capable of either interfering with microbial growth or hamper the adhesion to surfaces, with Staph. aureus proving to be the most susceptible micro-organism. The overall study demonstrates the potential of anthocyanin extracts as natural effective alternative antimicrobial agents. Additionally, the extract's capacity to reduce adhesion without reducing bacterial growth reduces the likeliness of resistance development while reducing the probability of infection. © 2016 The Society for Applied Microbiology.

Black Currant (Ribes nigrum L.) and Bilberry (Vaccinium myrtillus L.) Fruit Juices Inhibit Adhesion of Asaia spp.

PubMed Central

2016-01-01

The aim of the study was to evaluate the activity of high-polyphenolic black currant (Ribes nigrum L.) and bilberry (Vaccinium myrtillus L.) juices against bacterial strains Asaia lannensis and Asaia bogorensis isolated as spoilage of commercial soft drinks. The composition of fruit juices was evaluated using chromatographic techniques HPLC and LC-MS. The adhesion to glass, polystyrene, and polyethylene terephthalate in two different culture media was evaluated by luminometry and the plate count method. The major anthocyanins in the V. myrtillus were petunidin-3-glucoside, malvidin-3-glucoside, cyanidin-3-glucoside, and delphinidin-3-glucoside, while in R. nigrum delphinidin-3-rutinoside and cyanidin-3-rutinoside were detected. The LC-MS analysis showed presence of anthocyanins (delphinidin, cyanidin, petunidin, and malvidin derivatives), phenolic acids (chlorogenic and neochlorogenic acids), flavonols (quercetin-3-glucoside, quercetin-3-rutinoside), and flavanols (procyanidin B2 and procyanidin type A2). Additionally, in the bilberry juice A type procyanidin trimer was detected. The adhesion of Asaia spp. cells depended on the type of medium, carbon sources, and the type of abiotic surfaces. We noted that the adhesion was significantly stronger in minimal medium containing sucrose. The addition of bilberry and black currant juices notably reduced bacterial growth as well as cell adhesion to polyethylene terephthalate surfaces. PMID:27747228

Selective Adhesion of Thiobacillus ferrooxidans to Pyrite

PubMed Central

Ohmura, Naoya; Kitamura, Keiko; Saiki, Hiroshi

1993-01-01

Bacterial adhesion to mineral surfaces plays an important role not only in bacterial survival in natural ecosystems, but also in mining industry applications. Selective adhesion was investigated with Thiobacillus ferrooxidans by using four minerals, pyrite, quartz, chalcopyrite, and galena. Escherichia coli was used as a control bacterium. Contact angles were used as indicators of hydrophobicity, which was an important factor in the interaction between minerals and bacteria. The contact angle of E. coli in a 0.5% sodium chloride solution was 31°, and the contact angle of T. ferrooxidans in a pH 2.0 sulfuric acid solution was 23°. E. coli tended to adhere to more hydrophobic minerals by hydrophobic interaction, while T. ferrooxidans selectively adhered to iron-containing minerals, such as pyrite and chalcopyrite. Ferrous ion inhibited the selective adhesion of T. ferrooxidans to pyrite competitively, while ferric ion scarcely inhibited such adhesion. When selective adhesion was quenched by ferrous ion completely, adhesion of T. ferrooxidans was controlled by hydrophilic interactions. Adhesion of E. coli to pyrite exhibited a liner relationship on langmuir isotherm plots, but adhesion of T. ferrooxidans did not. T. ferrooxidans recognized the reduced iron in minerals and selectively adhered to pyrite and chalcopyrite by a strong interaction other than the physical interaction. PMID:16349106

Non-pharmacological treatment of Helicobacter pylori

PubMed Central

Shmuely, Haim; Domniz, Noam; Yahav, Jacob

2016-01-01

Many food and plant extracts have shown in vitro anti-Helicobacter pylori (H. pylori) activity, but are less effective in vivo. The anti-H. pylori effects of these extracts are mainly permeabilitization of the membrane, anti-adhesion, inhibition of bacterial enzymes and bacterial grown. We, herein, review treatment effects of cranberry, garlic, curcumin, ginger and pistacia gum against H. pylori in both in vitro, animal studies and in vivo studies. PMID:27158532

Curli mediate bacterial adhesion to fibronectin via tensile multiple bonds

NASA Astrophysics Data System (ADS)

Oh, Yoo Jin; Hubauer-Brenner, Michael; Gruber, Hermann J.; Cui, Yidan; Traxler, Lukas; Siligan, Christine; Park, Sungsu; Hinterdorfer, Peter

2016-09-01

Many enteric bacteria including pathogenic Escherichia coli and Salmonella strains produce curli fibers that bind to host surfaces, leading to bacterial internalization into host cells. By using a nanomechanical force-sensing approach, we obtained real-time information about the distribution of molecular bonds involved in the adhesion of curliated bacteria to fibronectin. We found that curliated E. coli and fibronectin formed dense quantized and multiple specific bonds with high tensile strength, resulting in tight bacterial binding. Nanomechanical recognition measurements revealed that approximately 10 bonds were disrupted either sequentially or simultaneously under force load. Thus the curli formation of bacterial surfaces leads to multi-bond structural components of fibrous nature, which may explain the strong mechanical binding of curliated bacteria to host cells and unveil the functions of these proteins in bacterial internalization and invasion.

Microbial specificity of metallic surfaces exposed to ambient seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaidi, B.R.; Bard, R.F.; Tosteson, T.R.

1984-09-01

High-molecular-weight materials associated with the extracellular matrix and film found on titanium and aluminum surfaces after exposure to flowing coastal seawater were isolated. This material was purified by hydroxylapatite chromatography and subsequently employed to produce antibodies in the toad, Bufo marinus. The antibodies were immobilized on a solid support and employed to isolate adhesion-enhancing, high-molecular-weight materials from the laboratory culture media of bacterial strains recovered from the respective metallic surfaces during the course of their exposure to seawater. The adhesion-enhancing materials produced by the surface-associated bacterial strains were immunologically related to the extracellular biofouling matrix material found on the surfacesmore » from which these bacteria were isolated. The surface selectivity of these bacterial strains appeared to be based on the specificity of the interaction between adhesion-enhancing macromolecules produced by these bacteria and the surfaces in question. 30 references, 6 tables.« less

Atomic force microscopy measurements of bacterial adhesion and biofilm formation onto clay-sized particles

PubMed Central

Huang, Qiaoyun; Wu, Huayong; Cai, Peng; Fein, Jeremy B.; Chen, Wenli

2015-01-01

Bacterial adhesion onto mineral surfaces and subsequent biofilm formation play key roles in aggregate stability, mineral weathering, and the fate of contaminants in soils. However, the mechanisms of bacteria-mineral interactions are not fully understood. Atomic force microscopy (AFM) was used to determine the adhesion forces between bacteria and goethite in water and to gain insight into the nanoscale surface morphology of the bacteria-mineral aggregates and biofilms formed on clay-sized minerals. This study yields direct evidence of a range of different association mechanisms between bacteria and minerals. All strains studied adhered predominantly to the edge surfaces of kaolinite rather than to the basal surfaces. Bacteria rarely formed aggregates with montmorillonite, but were more tightly adsorbed onto goethite surfaces. This study reports the first measured interaction force between bacteria and a clay surface, and the approach curves exhibited jump-in events with attractive forces of 97 ± 34 pN between E. coli and goethite. Bond strengthening between them occurred within 4 s to the maximum adhesion forces and energies of −3.0 ± 0.4 nN and −330 ± 43 aJ (10−18 J), respectively. Under the conditions studied, bacteria tended to form more extensive biofilms on minerals under low rather than high nutrient conditions. PMID:26585552

Forces involved in bacterial adhesion to hydrophilic and hydrophobic surfaces.

PubMed

Boks, Niels P; Norde, Willem; van der Mei, Henny C; Busscher, Henk J

2008-10-01

Using a parallel-plate flow chamber, the hydrodynamic shear forces to prevent bacterial adhesion (F(prev)) and to detach adhering bacteria (F(det)) were evaluated for hydrophilic glass, hydrophobic, dimethyldichlorosilane (DDS)-coated glass and six different bacterial strains, in order to test the following three hypotheses. 1. A strong hydrodynamic shear force to prevent adhesion relates to a strong hydrodynamic shear force to detach an adhering organism. 2. A weak hydrodynamic shear force to detach adhering bacteria implies that more bacteria will be stimulated to detach by passing an air-liquid interface (an air bubble) through the flow chamber. 3. DLVO (Derjaguin, Landau, Verwey, Overbeek) interactions determine the characteristic hydrodynamic shear forces to prevent adhesion and to detach adhering micro-organisms as well as the detachment induced by a passing air-liquid interface. F(prev) varied from 0.03 to 0.70 pN, while F(det) varied from 0.31 to over 19.64 pN, suggesting that after initial contact, strengthening of the bond occurs. Generally, it was more difficult to detach bacteria from DDS-coated glass than from hydrophilic glass, which was confirmed by air bubble detachment studies. Calculated attractive forces based on the DLVO theory (F(DLVO)) towards the secondary interaction minimum were higher on glass than on DDS-coated glass. In general, all three hypotheses had to be rejected, showing that it is important to distinguish between forces acting parallel (hydrodynamic shear) and perpendicular (DLVO, air-liquid interface passages) to the substratum surface.

Effect of cholesterol deposition on bacterial adhesion to contact lenses.

PubMed

Babaei Omali, Negar; Zhu, Hua; Zhao, Zhenjun; Ozkan, Jerome; Xu, Banglao; Borazjani, Roya; Willcox, Mark D P

2011-08-01

To examine the effect of cholesterol on the adhesion of bacteria to silicone hydrogel contact lenses. Contact lenses, collected from subjects wearing Acuvue Oasys or PureVision lenses, were extracted in chloroform:methanol (1:1, v/v) and amount of cholesterol was estimated by thin-layer chromatography. Unworn lenses were soaked in cholesterol, and the numbers of Pseudomonas aeruginosa strains or Staphylococcus aureus strains that adhered to the lenses were measured. Cholesterol was tested for effects on bacterial growth by incubating bacteria in medium containing cholesterol. From ex vivo PureVision lenses, 3.4 ± 0.3 μg/lens cholesterol was recovered, and from Acuvue Oasys lenses, 2.4 ± 0.2 to 1.0 ± 0.1 μg/lens cholesterol was extracted. Cholesterol did not alter the total or viable adhesion of any strain of P. aeruginosa or S. aureus (p > 0.05). However, worn PureVision lenses reduced the numbers of viable cells of P. aeruginosa (5.8 ± 0.4 log units) compared with unworn lenses (6.4 ± 0.2 log units, p = 0.001). Similarly, there were fewer numbers of S. aureus 031 adherent to worn PureVision (3.05 ± 0.8 log units) compared with unworn PureVision (4.6 ± 0.3 log units, p = 0.0001). Worn Acuvue Oasys lenses did not affect bacterial adhesion. Cholesterol showed no effect on the growth of any test strain. Although cholesterol has been shown to adsorb to contact lenses during wear, this lipid does not appear to modulate bacterial adhesion to a lens surface.

Biosensor studies of collagen and laminin binding with immobilized Escherichia coli O157:H7 and inhibition with naturally occurring food additives

NASA Astrophysics Data System (ADS)

Medina, Marjorie B.

1999-01-01

Escherichia coli O157:H7 outbreaks were mostly due to consumption of undercooked contaminated beef which resulted in severe illness and several fatalities. Recalls of contaminated meat are costly for the meat industry. Our research attempts to understand the mechanisms of bacterial adhesion on animal carcass in order to eliminate or reduce pathogens in foods. We have reported the interactions of immobilized E. coli O157:H7 cells with extracellular matrix (ECM) components using a surface plasmon resonance biosensor (BIAcore). These studies showed that immobilized bacterial cells allowed the study of real-time binding interactions of bacterial surface with the ECM compounds, collagen I, laminin and fibronectin. Collagen I and laminin bound to the E. coli sensor surface with dissociation and association rates ranging from 106 to 109. Binding of collagen I and laminin mixture resulted in synergistic binding signals. An inhibition model was derived using collagen-laminin as the ligand which binds with E. coli sensor. A select group of naturally occurring food additives was evaluated by determining their effectivity in inhibiting the collagen-laminin binding to the bacterial sensor. Bound collagen-laminin was detached from the E. coli sensor surface with the aid of an organic acid. The biosensor results were verified with cell aggregation assays which were observed with optical and electron microscopes. These biosensor studies provided understanding of bacterial adhesion to connective tissue macromolecules. It also provided a model system for the rapid assessment of potential inhibitors that can be used in carcass treatment to inhibit or reduce bacterial contamination.

Extract of corn silk (stigma of Zea mays) inhibits the tumour necrosis factor-alpha- and bacterial lipopolysaccharide-induced cell adhesion and ICAM-1 expression.

PubMed

Habtemariam, S

1998-05-01

Treatment of human endothelial cells with cytokines such as tumour necrosis factor-alpha (TNF) or E. coli lipopolysaccharide (LPS) induces the expression of several adhesion molecules and enhances leukocyte adhesion to endothelial cell surface. Interfering with this leukocyte adhesion or adhesion molecules upregulation is an important therapeutic target for the treatment of bacterial sepsis and various inflammatory diseases. In the course of screening marketed European anti-inflammatory herbal drugs for TNF antagonistic activity, a crude ethanolic extract of corn silk (stigma of Zea mays) exhibited significant activity. The extract at concentrations of 9-250 micrograms/ml effectively inhibited the TNF- and LPS-induced adhesiveness of EAhy 926 endothelial cells to monocytic U937 cells. Similar concentration ranges of corn silk extract did also block the TNF and LPS but not the phorbol 12-myristate 13-acetate-induced ICAM-1 expression on EAhy 926 endothelial cell surface. The extract did not alter the production of TNF by LPS-activated macrophages and failed to inhibit the cytotoxic activity of TNF. It is concluded that corn silk possesses important therapeutic potential for TNF- and LPS-mediated leukocyte adhesion and trafficking.

Novel protein-repellent dental adhesive containing 2-methacryloyloxyethyl phosphorylcholine

PubMed Central

Zhang, Ning; Melo, Mary Anne S.; Bai, Yuxing; Xu, Hockin H. K.

2015-01-01

Objectives Biofilms at tooth-restoration margins can produce acids and cause secondary caries. A protein-repellent adhesive resin can potentially inhibition bacteria attachment and biofilm growth. However, there has been no report on protein-repellent dental resins. The objectives of this study were to develop a protein-repellent bonding agent incorporating 2-methacryloyloxyethyl phosphorylcholine (MPC), and to investigate its resistance to protein adsorption and biofilm growth for the first time. Methods MPC was incorporated into Scotchbond Multi-Purpose (SBMP) at 0%, 3.75%, 7.5%, 11.25%, and 15% by mass. Extracted human teeth were used to measure dentin shear bond strengths. Protein adsorption onto resins was determined by a micro bicinchoninic acid (BCA) method. A dental plaque microcosm biofilm model with human saliva as inoculum was used to measure biofilm metabolic activity and colony-forming unit (CFU) counts. Results Adding 7.5% MPC into primer and adhesive did not decrease the dentin bond strength, compared to control (p > 0.1). Incorporation of 7.5% of MPC achieved the lowest protein adsorption, which was 20-fold less than that of control. Incorporation of 7.5% of MPC greatly reduced bacterial adhesion, yielding biofilm total microorganism, total streptococci, and mutans streptococci CFU that were an order of magnitude less than control. Conclusions A protein-repellent dental adhesive resin was developed for the first time. Incorporation of MPC into primer and adhesive at 7.5% by mass greatly reduced the protein adsorption and bacterial adhesion, without compromising the dentin bond strength. The novel protein-repellent primer and adhesive are promising to inhibit biofilm formation and acid production, to protect the tooth-restoration margins and prevent secondary caries. PMID:25234652

Marine Bacterial Polysaccharide EPS11 Inhibits Cancer Cell Growth via Blocking Cell Adhesion and Stimulating Anoikis

PubMed Central

Cao, Ruobing; Jin, Weihua; Shan, Yeqi; Wang, Ju; Liu, Ge; Kuang, Shan

2018-01-01

Tumor cells that acquire metastatic potential have developed resistance to anoikis, a cell death process, after detachment from their primary site to the second organ. In this study, we investigated the molecular mechanisms of a novel marine bacterial polysaccharide EPS11 which exerts its cytotoxic effects through affecting cancer cell adhesion and anoikis. Firstly, we found that EPS11 could significantly affect cell proliferation and block cell adhesion in A549 cells. We further demonstrated that the expression of several cell adhesion associated proteins is downregulated and the filiform structures of cancer cells are destroyed after EPS11 treatment. Interestingly, the destruction of filiform structures in A549 cells by EPS11 is in a dose-dependent manner, and the inhibitory tendency is very consistent with that observed in the cell adhesion assay, which confirms that filiform structures play important roles in modulating cell adhesion. Moreover, we showed that EPS11 induces apoptosis of A549 cells through stimulating βIII-tubulin associated anoikis: (i) EPS11 inhibits the expression of βIII-tubulin in both transcription and translation levels; and (ii) EPS11 treatment dramatically decreases the phosphorylation of protein kinase B (PKB or AKT), a critical downstream effector of βIII-tubulin. Importantly, EPS11 evidently inhibits the growth of A549-derived tumor xenografts in vivo. Thus, our results suggest that EPS11 may be a potential candidate for human non-small cell lung carcinoma treatment via blocking filiform structure mediated adhesion and stimulating βIII-tubulin associated anoikis. PMID:29518055

Nonadhesive, silica nanoparticles-based brush-coated contact lens cases--compromising between ease of cleaning and microbial transmission to contact lenses.

PubMed

Qu, Wenwen; Hooymans, Johanna M M; Qiu, Jun; de-Bont, Nik; Gelling, Onko-Jan; van der Mei, Henny C; Busscher, Henk J

2013-05-01

Surface properties of lens cases are determinant for their cleanability and for microbial transmission from lens cases to contact lenses (CLs). PEG-polymer-brush-coatings are known to decrease microbial adhesion more than other surface-coatings. Here, we applied a robust, silica nanoparticles-based brush-coating to polypropylene cases to evaluate their ease of cleaning and probability of bacterial transmission to CLs. Adhesion forces of nine bacterial strains (Pseudomonas, Staphylococci, and Serratia) to rigid CLs, polypropylene, and silica nanoparticles-based brush-coated polypropylene were measured using atomic-force-microscopy and subjected to Weibull analyses to yield bacterial transmission probabilities. Biofilms of each strain were grown in coated and uncoated cases and rinsed with a NaCl or antimicrobial lens care solution. Residual, viable organisms were quantified. Bacterial adhesion forces of all strains were significantly, up to tenfold smaller on brush-coated than on uncoated polypropylene. This yielded, higher transmission probabilities to a CL, but mild-rinsing yielded 10-100 fold higher removal of bacteria from brush-coated than from polypropylene cases. Moreover, due to weak adhesion forces, bacteria on brush-coated cases were two-to-three fold more susceptible to an antimicrobial lens care solution than on polypropylene cases. Therewith, the design of lens case surfaces is a compromise between ease of cleaning and transmission probability to CLs. Copyright © 2013 Wiley Periodicals, Inc.

Development and characterization of a stable adhesive bond between a poly(dimethylsiloxane) catheter material and a bacterial biofilm resistant acrylate polymer coating

PubMed Central

Tyler, Bonnie J.; Hook, Andrew; Pelster, Andreas; Williams, Paul; Alexander, Morgan; Arlinghaus, Heinrich F.

2017-01-01

Catheter associated urinary tract infections are the most common health related infections worldwide, contributing significantly to patient morbidity and mortality and increased health care costs. To reduce the incidence of these infections, new materials that resist bacterial biofilm formation are needed. A composite catheter material, consisting of bulk poly(dimethylsiloxane) (PDMS) coated with a novel bacterial biofilm resistant polyacrylate [ethylene glycol dicyclopentenyl ether acrylate (EGDPEA)-co-di(ethyleneglycol) methyl ether methacrylate (DEGMA)], has been proposed. The coated material shows excellent bacterial resistance when compared to commercial catheter materials, but delamination of the EGDPEA-co-DEGMA coatings under mechanical stress presents a challenge. In this work, the use of oxygen plasma treatment to improve the wettability and reactivity of the PDMS catheter material and improve adhesion with the EGDPEA-co-DEGMA coating has been investigated. Argon cluster three dimensional-imaging time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been used to probe the buried adhesive interface between the EGDPEA-co-DEGMA coating and the treated PDMS. ToF-SIMS analysis was performed in both dry and frozen-hydrated states, and the results were compared to mechanical tests. From the ToF-SIMS data, the authors have been able to observe the presence of PDMS, silicates, salt particles, cracks, and water at the adhesive interface. In the dry catheters, low molecular weight PDMS oligomers at the interface were associated with poor adhesion. When hydrated, the hydrophilic silicates attracted water to the interface and led to easy delamination of the coating. The best adhesion results, under hydrated conditions, were obtained using a combination of 5 min O2 plasma treatment and silane primers. Cryo-ToF-SIMS analysis of the hydrated catheter material showed that the bond between the primed PDMS catheter and the EGDPEA-co-DEGMA coating was stable in the presence of water. The resulting catheter material resisted Escherichia coli and Proteus mirabilis biofilm colonization by up to 95% compared with uncoated PDMS after 10 days of continuous bacterial exposure and had the mechanical properties necessary for use as a urinary catheter. PMID:28535686

Effect of phospholipid deposits on adhesion of bacteria to contact lenses.

PubMed

Babaei Omali, Negar; Proschogo, Nicholas; Zhu, Hua; Zhao, Zhenjun; Diec, Jennie; Borazjani, Roya; Willcox, Mark D P

2012-01-01

Protein and lipid deposits on contact lenses may contribute to clinical complications. This study examined the effect of phospholipids on the adhesion of bacteria to contact lenses. Worn balafilcon A (n = 11) and senofilcon A (n = 11) were collected after daily wear and phospholipids were extracted in chloroform:methanol. The amount of phospholipid was measured by electrospray ionization mass spectrometry. Unworn lenses soaked in phospholipids were exposed to Pseudomonas aeruginosa and Staphylococcus aureus. After 18 h incubation, the numbers of P. aeruginosa or S. aureus that adhered to the lenses were measured. Phospholipid was tested for possible effects on bacterial growth. A broad range of sphingomyelins (SM) and phosphatidylcholines (PC) were detected from both types of worn lenses. SM (16:0) (m/z 703) and PC (34:2) (m/z 758) were the major phospholipids detected in the lens extracts. Phospholipids did not alter the adhesion of any strain of P. aeruginosa or S. aureus (p > 0.05). Phospholipids (0.1 mg/mL) showed no effect on the growth of P. aeruginosa 6294 or S. aureus 031. Phospholipids adsorb/absorb to contact lenses during wear, however, the major types of phospholipids adsorbed to lenses do not alter bacterial adhesion or growth.

Electrochemical monitoring of chlorhexidine digluconate effect on polyelectrolyte immobilized bacteria and kinetic cell adhesion.

PubMed

Borghol, N; Mora, L; Sakly, N; Lejeune, P; Jouenne, T; Jaffrézic-Renault, N; Othmane, A

2011-01-10

The electrochemical impedance spectroscopy (EIS) technique has been used as a sensitive method to explore the effect of antibacterial molecules on immobilized bacteria and biofilm formation. In this work, we describe the electrochemical spectroscopy as a powerful method to monitor the effect of chlorhexidine digluconate (CHX-Dg) on polyelectrolyte immobilized Escherichia coli K12 MG1655 and the kinetics of cell adhesion on gold electrodes. The experimental impedance data were modeled with a Zview program to find the best equivalent electrical circuit and analyse its parameter's properties. Polyelectrolyte multilayer formation on the electrode surface and bacteria immobilization greatly increased the electron-transfer resistance (R(et)) and reduced the constant phase element (CPE(dl)). The effect of CHX-Dg was studied in a 0.5 x 10⁻⁴ mmol l⁻¹ to 0.5 mmol l⁻¹ range. The relation between the evolution of R(et) and CHX-Dg concentration was found to be negatively correlated. When CHX-Dg was added, the electrochemical monitoring of the bacterial kinetic adhesion showed that the electrode's capacity (C(P)) variation remained stable, demonstrating that the addition of CHX-Dg in the broth inhibited bacterial adhesion. © 2010 Elsevier B.V. All rights reserved.

Structural and compositional characterization of the adhesive produced by reef building oysters.

PubMed

Alberts, Erik M; Taylor, Stephen D; Edwards, Stephanie L; Sherman, Debra M; Huang, Chia-Ping; Kenny, Paul; Wilker, Jonathan J

2015-04-29

Oysters have an impressive ability to overcome difficulties of life within the stressful intertidal zone. These shellfish produce an adhesive for attaching to each other and building protective reef communities. With their reefs often exceeding kilometers in length, oysters play a major role in balancing the health of coastal marine ecosystems. Few details are available to describe oyster adhesive composition or structure. Here several characterization methods were applied to describe the nature of this material. Microscopy studies indicated that the glue is comprised of organic fiber-like and sheet-like structures surrounded by an inorganic matrix. Phospholipids, cross-linking chemistry, and conjugated organics were found to differentiate this adhesive from the shell. Symbiosis in material synthesis could also be present, with oysters incorporating bacterial polysaccharides into their adhesive. Oyster glue shows that an organic-inorganic composite material can provide adhesion, a property especially important when constructing a marine ecosystem.

Influence of biofilm lubricity on shear-induced transmission of staphylococcal biofilms from stainless steel to silicone rubber.

PubMed

Gusnaniar, Niar; Sjollema, Jelmer; Jong, Ed D; Woudstra, Willem; de Vries, Joop; Nuryastuti, Titik; van der Mei, Henny C; Busscher, Henk J

2017-11-01

In real-life situations, bacteria are often transmitted from biofilms growing on donor surfaces to receiver ones. Bacterial transmission is more complex than adhesion, involving bacterial detachment from donor and subsequent adhesion to receiver surfaces. Here, we describe a new device to study shear-induced bacterial transmission from a (stainless steel) pipe to a (silicone rubber) tube and compare transmission of EPS-producing and non-EPS-producing staphylococci. Transmission of an entire biofilm from the donor to the receiver tube did not occur, indicative of cohesive failure in the biofilm rather than of adhesive failure at the donor-biofilm interface. Biofilm was gradually transmitted over an increasing length of receiver tube, occurring mostly to the first 50 cm of the receiver tube. Under high-shearing velocity, transmission of non-EPS-producing bacteria to the second half decreased non-linearly, likely due to rapid thinning of the lowly lubricious biofilm. Oppositely, transmission of EPS-producing strains to the second tube half was not affected by higher shearing velocity due to the high lubricity and stress relaxation of the EPS-rich biofilms, ensuring continued contact with the receiver. The non-linear decrease of ongoing bacterial transmission under high-shearing velocity is new and of relevance in for instance, high-speed food slicers and food packaging. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

A new mathematical model of bacterial interactions in two-species oral biofilms

PubMed Central

Martin, Bénédicte; Tamanai-Shacoori, Zohreh; Bronsard, Julie; Ginguené, Franck; Meuric, Vincent

2017-01-01

Periodontitis are bacterial inflammatory diseases, where the bacterial biofilms present on the tooth-supporting tissues switch from a healthy state towards a pathogenic state. Among bacterial species involved in the disease, Porphyromonas gingivalis has been shown to induce dysbiosis, and to induce virulence of otherwise healthy bacteria like Streptococcus gordonii. During biofilm development, primary colonizers such as S. gordonii first attach to the surface and allow the subsequent adhesion of periodontal pathogens such as P. gingivalis. Interactions between those two bacteria have been extensively studied during the adhesion step of the biofilm. The aim of the study was to understand interactions of both species during the growing phase of the biofilm, for which little knowledge is available, using a mathematical model. This two-species biofilm model was based on a substrate-dependent growth, implemented with damage parameters, and validated thanks to data obtained on experimental biofilms. Three different hypothesis of interactions were proposed and assayed using this model: independence, competition between both bacteria species, or induction of toxicity by one species for the other species. Adequacy between experimental and simulated biofilms were found with the last hypothetic mathematical model. This new mathematical model of two species bacteria biofilms, dependent on different substrates for growing, can be applied to any bacteria species, environmental conditions, or steps of biofilm development. It will be of great interest for exploring bacterial interactions in biofilm conditions. PMID:28253369

A relatively small change in sodium chloride concentration has a strong effect on adhesion of ocular bacteria to contact lenses.

PubMed

Cowell, B A; Willcox, M D; Schneider, R P

1998-06-01

Adhesion of bacteria to hydrogel lenses is thought to be an initial step of ocular colonization allowing evasion of normal host defences. The salt concentration of media is an important parameter controlling microbial adhesion. Salinity varies from 0.97% NaCl equivalents in the open eye to 0.89% in the closed eye state. In this study, the effect of sodium chloride in the concentration range of 0.8-1.0% (w/v) NaCl on adhesion of ocular bacteria to soft contact lenses was investigated using a static adhesion assay. Pseudomonas aeruginosa was found to adhere to lenses in significantly greater amounts than Serratia marcescens, Flavobacterium meningosepticum, Stenotrophomonas maltophilia and Staphylococcus intermedius. Increasing NaCl from 0.8% to 1.0% (w/v) increased adhesion of all bacteria tested. This adhesion was strong since the organisms could not be removed by washing in low ionic buffer. Adhesion of these organisms did not correlate with their cell surface properties as determined by bacterial adhesion to hydrocarbons (BATH) and retention on sepharose columns.

A liposomal hydrogel for the prevention of bacterial adhesion to catheters.

PubMed

DiTizio, V; Ferguson, G W; Mittelman, M W; Khoury, A E; Bruce, A W; DiCosmo, F

1998-10-01

The adhesion of bacteria to medical implants and the subsequent development of a biofilm frequently results in the infection of surrounding tissue and may require removal of the device. We have developed a liposomal hydrogel system that significantly reduces bacterial adhesion to silicone catheter material. The system consists of a poly (ethylene glycol)-gelatin hydrogel in which liposomes containing the antibiotic ciprofloxacin are sequestered. A poly (ethylene glycol)-gelatin-liposome mixture was applied to a silicone surface that had been pre-treated with phenylazido-modified gelatin. Hydrogel cross-linking and attachment to surface-immobilized gelatin was accomplished through the formation of urethane bonds between gelatin and nitrophenyl carbonate-activated poly (ethylene glycol). Liposomal hydrogel-coated catheters were shown to have an initial ciprofloxacin content of 185+/-16 microg cm(-2). Ciprofloxacin was released over seven days with an average release rate of 1.9+/-0.2 microg cm(-2) h(-1) for the first 94 h. In vitro assays using a clinical isolate of Pseudomonas aeruginosa established the antimicrobial efficacy of the liposomal hydrogel. A modified Kirby-Bauer assay produced growth-inhibition zone diameters of 39+/-1 mm, while bacterial adhesion was completely inhibited on catheter surfaces throughout a seven-day in vitro adhesion assay. This new antimicrobial coating shows promise as a prophylactic and/or treatment for catheter-related infection.

Streptococcus pyogenes CAMP factor promotes bacterial adhesion and invasion in pharyngeal epithelial cells without serum via PI3K/Akt signaling pathway.

PubMed

Kurosawa, Mie; Oda, Masataka; Domon, Hisanori; Isono, Toshihito; Nakamura, Yuki; Saitoh, Issei; Hayasaki, Haruaki; Yamaguchi, Masaya; Kawabata, Shigetada; Terao, Yutaka

2018-01-01

Streptococcus pyogenes is a bacterium that causes systemic diseases, such as pharyngitis and toxic shock syndrome, via oral- or nasal-cavity infection. S. pyogenes produces various molecules known to function with serum components that lead to bacterial adhesion and invasion in human tissues. In this study, we identified a novel S. pyogenes adhesin/invasin. Our results revealed that CAMP factor promoted streptococcal adhesion and invasion in pharyngeal epithelial Detroit562 cells without serum. Recombinant CAMP factor initially localized on the membranes of cells and then became internalized in the cytosol following S. pyogenes infection. Additionally, CAMP factor phosphorylated phosphoinositide 3-kinase and serine-threonine kinase in the cells. ELISA results demonstrate that CAMP factor affected the amount of phosphorylated phosphoinositide 3-kinase and serine-threonine kinase in Detroit562 cells. Furthermore, CAMP factor did not reverse the effect of phosphoinositide 3-kinase knockdown by small interfering RNA in reducing the level of adhesion and invasion of S. pyogenes isogenic cfa-deficient mutant. These results suggested that S. pyogenes CAMP factor activated the phosphoinositide 3-kinase/serine-threonine kinase signaling pathway, promoting S. pyogenes invasion of Detroit562 cells without serum. Our findings suggested that CAMP factor played an important role on adhesion and invasion in pharyngeal epithelial cells. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Manuka honey inhibits adhesion and invasion of medically important wound bacteria in vitro.

PubMed

Maddocks, Sarah Elizabeth; Jenkins, Rowena Eleri; Rowlands, Richard Samuel; Purdy, Kevin John; Cooper, Rose Agnes

2013-12-01

To characterize the effect of manuka honey on medically important wound bacteria in vitro, focusing on its antiadhesive properties. Crystal violet biofilm assays, fluorescent microscopy, protein adhesion assay and gentamicin protection assay were used to determine the impact of manuka honey on biofilm formation, human protein binding and adherence to/invasion into human keratinocytes. Manuka honey effectively disrupted and caused extensive cell death in biofilms of Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus pyogenes. Sublethal doses of manuka honey inhibited bacterial adhesion to the fibronectin, fibrinogen and collagen. Manuka honey impaired adhesion of laboratory and clinical isolates of S. aureus, P. aeruginosa and S. pyogenes to human keratinocytes in vitro, and inhibited invasion by S. pyogenes and homogeneous vancomycin intermediate S. aureus. Manuka honey can directly affect bacterial cells embedded in a biofilm and exhibits antiadhesive properties against three common wound pathogens.

Inhibition of Pseudomonas aeruginosa adhesion to fibronectin by PA-IL and monosaccharides: involvement of a lectin-like process.

PubMed

Rebiere-Huët, Julie; Di Martino, Patrick; Hulen, Christian

2004-05-01

Pseudomonas aeruginosa adherence to fibronectin has been shown to be important to bacterial colonization and infection. To better understand the mechanisms involved in this interaction, the role of the carbohydrate moiety of the fibronectin molecule in P. aeruginosa adhesion was studied. Strain NK 125 502 adhered to immobilized fibronectin with an adherence index of 4.8 x 10(5) CFU/ micro g. Periodic oxidation of fibronectin markedly reduced the adhesion of P. aeruginosa, while a neuraminidase treatment increased bacteria adhesion. N-Acetylgalactosamine, N-acetylglucosamine, sialic acid, and also lectin PA-IL worked as efficient inhibitors in adhesion assays: 59%, 70.7%, 100%, and 60% of inhibition, respectively. We have demonstrated here the involvement of a lectin-like process in the interaction of P. aeruginosa NK 125 502 with immobilized fibronectin.

Investigating the BSA protein adsorption and bacterial adhesion of Al-alloy surfaces after creating a hierarchical (micro/nano) superhydrophobic structure.

PubMed

Moazzam, Parisa; Razmjou, Amir; Golabi, Mohsen; Shokri, Dariush; Landarani-Isfahani, Amir

2016-09-01

Bacterial adhesion and subsequent biofilm formation on metals such as aluminum (Al) alloys lead to serious issues in biomedical and industrial fields from both an economical and health perspective. Here, we showed that a careful manipulation of Al surface characteristics via a facile two-steps superhydrophobic modification can provide not only biocompatibility and an ability to control protein adsorption and bacterial adhesion, but also address the issue of apparent long-term toxicity of Al-alloys. To find out the roles of surface characteristics, surface modification and protein adsorption on microbial adhesion and biofilm formation, the surfaces were systematically characterized by SEM, EDX, XPS, AFM, FTIR, water contact angle (WCA) goniometry, surface free energy (SFE) measurement, MTT, Bradford, Lowry and microtiter plate assays and also flow-cytometry and potentiostat analyses. Results showed that WCA and SFE changed from 70° to 163° and 36.3 to 0.13 mN m(-1) , respectively. The stable and durable modification led to a substantial reduction in static/dynamic BSA adsorption. The effect of such a treatment on the biofilm formation was analyzed by using three different bacteria of Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus. The microtiter plate assay and flow cytometry analysis showed that the modification not only could substantially reduce the bacterial adhesion but this biofouling resistance is independent of bacterium type. An excellent cell viability after exposure of HeLa cells to waters incubated with the modified samples was observed. Finally, the corrosion rate reduced sharply from 856.6 to 0.119 MPY after superhydrophobic modifications, which is an excellent stable corrosion inhibition property. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2220-2233, 2016. © 2016 Wiley Periodicals, Inc.

Predictive modelling of a novel anti-adhesion therapy to combat bacterial colonisation of burn wounds

PubMed Central

Huebinger, Ryan M.; Keen, Emma

2018-01-01

As the development of new classes of antibiotics slows, bacterial resistance to existing antibiotics is becoming an increasing problem. A potential solution is to develop treatment strategies with an alternative mode of action. We consider one such strategy: anti-adhesion therapy. Whereas antibiotics act directly upon bacteria, either killing them or inhibiting their growth, anti-adhesion therapy impedes the binding of bacteria to host cells. This prevents bacteria from deploying their arsenal of virulence mechanisms, while simultaneously rendering them more susceptible to natural and artificial clearance. In this paper, we consider a particular form of anti-adhesion therapy, involving biomimetic multivalent adhesion molecule 7 coupled polystyrene microbeads, which competitively inhibit the binding of bacteria to host cells. We develop a mathematical model, formulated as a system of ordinary differential equations, to describe inhibitor treatment of a Pseudomonas aeruginosa burn wound infection in the rat. Benchmarking our model against in vivo data from an ongoing experimental programme, we use the model to explain bacteria population dynamics and to predict the efficacy of a range of treatment strategies, with the aim of improving treatment outcome. The model consists of two physical compartments: the host cells and the exudate. It is found that, when effective in reducing the bacterial burden, inhibitor treatment operates both by preventing bacteria from binding to the host cells and by reducing the flux of daughter cells from the host cells into the exudate. Our model predicts that inhibitor treatment cannot eliminate the bacterial burden when used in isolation; however, when combined with regular or continuous debridement of the exudate, elimination is theoretically possible. Lastly, we present ways to improve therapeutic efficacy, as predicted by our mathematical model. PMID:29723210

A modular reactor to simulate biofilm development in orthopedic materials.

PubMed

Barros, Joana; Grenho, Liliana; Manuel, Cândida M; Ferreira, Carla; Melo, Luís F; Nunes, Olga C; Monteiro, Fernando J; Ferraz, Maria P

2013-09-01

Surfaces of medical implants are generally designed to encourage soft- and/or hard-tissue adherence, eventually leading to tissue- or osseo-integration. Unfortunately, this feature may also encourage bacterial adhesion and biofilm formation. To understand the mechanisms of bone tissue infection associated with contaminated biomaterials, a detailed understanding of bacterial adhesion and subsequent biofilm formation on biomaterial surfaces is needed. In this study, a continuous-flow modular reactor composed of several modular units placed in parallel was designed to evaluate the activity of circulating bacterial suspensions and thus their predilection for biofilm formation during 72 h of incubation. Hydroxyapatite discs were placed in each modular unit and then removed at fixed times to quantify biofilm accumulation. Biofilm formation on each replicate of material, unchanged in structure, morphology, or cell density, was reproducibly observed. The modular reactor therefore proved to be a useful tool for following mature biofilm formation on different surfaces and under conditions similar to those prevailing near human-bone implants.

Bacterial DNA induces pulmonary damage via TLR-9 through cross-talk with neutrophils.

PubMed

Itagaki, Kiyoshi; Adibnia, Yasaman; Sun, Shiqin; Zhao, Cong; Sursal, Tolga; Chen, Yu; Junger, Wolfgang; Hauser, Carl J

2011-12-01

Bacterial DNA (bDNA) contains hypomethylated "CpG" repeats that can be recognized by Toll-like receptor 9 (TLR-9) as a pathogen-associated molecular pattern. The ability of bDNA to initiate lung injury via TLR-9 has been inferred on the basis of studies using artificial CpG DNA. But the role of authentic bDNA in lung injury is still unknown. Moreover, the mechanisms by which CpG DNA species can lead to pulmonary injury are unknown, although neutrophils (PMNs) are thought to play a key role in the genesis of septic acute lung injury. We evaluated the effects of bDNA on PMN-endothelial cell (EC) interactions thought critical for initiation of acute lung injury. Using a biocapacitance system to monitor real-time changes in endothelial permeability, we demonstrate here that bDNA causes EC permeability in a dose-dependent manner uniquely in the presence of PMNs. These permeability changes are inhibited by chloroquine, suggesting TLR-9 dependency. When PMNs were preincubated with bDNA and applied to ECs or when bDNA was applied to ECs without PMNs, no permeability changes were detected. To study the underlying mechanisms, we evaluated the effects of bDNA on PMN-EC adherence. Bacterial DNA significantly increased PMN adherence to ECs in association with upregulated adhesion molecules in both cell types. Taken together, our results strongly support the conclusion that bDNA can initiate lung injury by stimulating PMN-EC adhesive interactions predisposing to endothelial permeability. Bacterial DNA stimulation of TLR-9 appears to promote enhanced gene expression of adhesion molecules in both cell types. This leads to PMN-EC cross-talk, which is required for injury to occur.

Hydrogels with Modulated Ionic Load for Mammalian Cell Harvesting with Reduced Bacterial Adhesion.

PubMed

Gallardo, Alberto; Martínez-Campos, Enrique; García, Carolina; Cortajarena, Aitziber L; Rodríguez-Hernández, Juan

2017-05-08

In this manuscript, we describe the fabrication of hydrogel supports for mammalian cell handling that can simultaneously prevent materials from microbial contamination and therefore allow storage in aqueous media. For that purpose, hydrogels based on the antifouling polymer polyvinylpyrrolidone (PVP) were functionalized with different ionic groups (anionic, cationic, or two types of zwitterions). In order to prevent bacterial adhesion in the long-term, we took advantage of the synergistic effect of inherently antifouling PVP and additional antifouling moieties incorporated within the hydrogel structure. We evaluated, in a separated series of experiments, both the capability of the materials to act as supports for the growth of mammalian cell monolayers for transplantation (using C-166-GFP endothelial cell line), as well their antifouling properties against Staphylococcus aureus, were studied. All of the hydrogels are structurally pseudodouble networks with high swelling (around 90%) and similar mechanical properties (in the low range for hydrogel materials with Young modulus below 1250 kPa). With some differences, all the charged hydrogels were capable of hosting mouse endothelial cell line C166-GFP to confluence, as well as a monolayer detachment and transplantation through simple mechanical agitation. On the contrary, the uncharged hydrogel was not capable to detach a full monolayer for transplantation. Bacterial adhesion and proliferation was highly sensitive to the functionality (type of charge and density). In particular, we evidenced that monomers bearing zwitterionic sulfobetaine groups, those negatively charged as well as "electro neutral" hydrogels fabricated from stoichiometric amounts of positive and negative units, exhibit excellent antifouling properties both at initial adhesion times and during longer periods up to 72 h.

Involvement of Escherichia coli K1 ibeT in bacterial adhesion that is associated with the entry into human brain microvascular endothelial cells.

PubMed

Zou, Yanming; He, Lina; Chi, Feng; Jong, Ambrose; Huang, Sheng-He

2008-12-01

IbeT is a downstream gene of the invasion determinant ibeA in the chromosome of a clinical isolate of Escherichia coli K1 strain RS218 (serotype 018:K1:H7). Both ibeT and ibeA are in the same operon. Our previous mutagenesis and complementation studies suggested that ibeT may coordinately contribute to E. coli K1 invasion with ibeA. An isogenic in-frame deletion mutant of ibeT has been made by chromosomal gene replacement with a recombinant suicide vector carrying a fragment with an ibeT internal deletion. The characteristics of the mutant in meningitic E. coli infection were examined in vitro [cell culture of human brain microvascular endothelial cells (HBMEC)] and in vivo (infant rat model of E. coli meningitis) in comparison with the parent strain. The ibeT deletion mutant was significantly less adhesive and invasive than its parent strain E. coli E44 in vitro, and the adhesion- and invasion-deficient phenotypes of the mutant can be complemented by the ibeT gene. Recombinant IbeT protein is able to block E. coli E44 invasion of HBMEC. Furthermore, the ibeT deletion mutant is less capable of colonizing intestine and less virulent in bacterial translocation across the blood-brain barrier (BBB) than its parent E. coli E44 in vivo. These data suggest that ibeT-mediated E. coli K1 adhesion is associated with the bacterial invasion process.

Bacterial adhesion affinities of various implant abutment materials.

PubMed

Yamane, Koichi; Ayukawa, Yasunori; Takeshita, Toru; Furuhashi, Akihiro; Yamashita, Yoshihisa; Koyano, Kiyoshi

2013-12-01

To investigate bacterial adhesion to various abutment materials. Thirty volunteers participated in this study. Resin splints were fabricated, and five types of disks were fabricated from pure titanium, gold-platinum alloy, zirconia, alumina, and hydroxyapatite with uniform surface roughness and attached to the buccal surface of each splint. After 4 days of use by the subjects, the plaque accumulated on the disk surfaces was analyzed. The bacterial community structure was evaluated using 16S rRNA gene profiling with terminal restriction fragment length polymorphism analysis. The total bacterial count on each disk was estimated using quantitative polymerase chain reaction. Terminal restriction fragment length polymorphism profiles were more similar between tested materials than between subjects, suggesting that the bacterial community structures on the abutment material were influenced more by the individuals than by the type of material. However, the total number of bacteria attached to a disk was significantly different among five materials (P < 0.001, Brunner-Langer test for longitudinal data). Fewer bacteria were attached to the gold-platinum alloy than to the other materials. Gold-platinum alloy appears to be useful material for abutments when considering the accumulation of plaque. However, alternative properties of the abutment material, such as effects on soft tissue healing, should also be taken into consideration when choosing an abutment material. © 2012 John Wiley & Sons A/S.

Molecular mechanics of Staphylococcus aureus adhesin, CNA, and the inhibition of bacterial adhesion by stretching collagen

PubMed Central

Madani, Ali; Garakani, Kiavash

2017-01-01

Bacterial adhesion to collagen, the most abundant protein in humans, is a critical step in the initiation and persistence of numerous bacterial infections. In this study, we explore the collagen binding mechanism of the multi-modular cell wall anchored collagen adhesin (CNA) in Staphylococcus aureus and examine how applied mechanical forces can modulate adhesion ability. The common structural-functional elements and domain organization of CNA are present across over 50 genera of bacteria. Through the use of molecular dynamics models and normal mode analysis, we shed light on the CNA’s structural and conformational dynamics and its interactions with collagen that lead to collagen binding. Our results suggest that the linker region, CNA165-173, acts as a hinge exhibiting bending, extensional, and torsional modes of structural flexibility and its residues are key in the interaction of the CNA-collagen complex. Steered molecular dynamics simulations were conducted with umbrella sampling. During the course of these simulations, the ‘locking’ latch from the CNA N2 domain was dissociated from its groove in the CNA N1 domain, implying the importance of the latch for effective ligand binding. Finally, we observed that the binding efficiency of the CNA N1-N2 domains to collagen decreases greatly with increasing tensile force application to the collagen peptides. Thus, CNA and similar adhesins might preferentially bind to sites in which collagen fibers are cleaved, such as in wounded, injured, or inflamed tissues, or in which the collagenous tissue is less mature. As alternative techniques for control of bacterial infection are in-demand due to the rise of bacterial antibiotic resistance, results from our computational studies with respect to the mechanoregulation of the collagen binding site may inspire new therapeutics and engineering solutions by mechanically preventing colonization and/or further pathogenesis. PMID:28665944

Hyaluronic Acid and Its Composites as a Local Antimicrobial/Antiadhesive Barrier

PubMed Central

Romanò, C.L.; De Vecchi, E.; Bortolin, M.; Morelli, I.; Drago, L.

2017-01-01

Living in biofilms is probably the most common condition for bacteria and fungi and biofilm-related infections account for the majority of bacterial infectious diseases worldwide. Among others biofilm-related infections, those associated with implanted biomaterials have an enormous and still largely underestimated impact in orthopaedics and trauma, cardio-surgery and several other surgical disciplines. Given the limited efficacy of existing antibiotics in the prevention and treatment of bacterial biofilms, new strategies are needed to protect implants and host tissues, overcoming the striking ability of the microorganisms to adhere on different surfaces and to immediately protect themselves by forming the biofilm matrix. Adhesion is a necessary first step in microbial colonization and pathogenesis and provides a potential target for new preventive and treatment approach. Among various polymers, tested as antibacterial coatings, hyaluronic acid and some of its composites do offer a well-established long-term safety profile and a proven ability to reduce bacterial adhesion and biofilm formation. Aim of the present review is to summarize the available evidence concerning the antiadhesion/antibiofilm activity of hyaluronic acid and some of its derivatives to reduce/prevent bacterial adhesion and biofilm formation in various experimental and clinical settings. PMID:28529865

Polysaccharide-based antibiofilm surfaces.

PubMed

Junter, Guy-Alain; Thébault, Pascal; Lebrun, Laurent

2016-01-01

Surface treatment by natural or modified polysaccharide polymers is a promising means to fight against implant-associated biofilm infections. The present review focuses on polysaccharide-based coatings that have been proposed over the last ten years to impede biofilm formation on material surfaces exposed to bacterial contamination. Anti-adhesive and bactericidal coatings are considered. Besides classical hydrophilic coatings based on hyaluronic acid and heparin, the promising anti-adhesive properties of the algal polysaccharide ulvan are underlined. Surface functionalization by antimicrobial chitosan and derivatives is extensively surveyed, in particular chitosan association with other polysaccharides in layer-by-layer assemblies to form both anti-adhesive and bactericidal coatings. Bacterial contamination of surfaces, leading to biofilm formation, is a major problem in fields as diverse as medicine, first, but also food and cosmetics. Many prophylactic strategies have emerged to try to eliminate or reduce bacterial adhesion and biofilm formation on surfaces of materials exposed to bacterial contamination, in particular implant materials. Polysaccharides are widely distributed in nature. A number of these natural polymers display antibiofilm properties. Hence, surface treatment by natural or modified polysaccharides is a promising means to fight against implant-associated biofilm infections. The present manuscript is an in-depth look at polysaccharide-based antibiofilm surfaces that have been proposed over the last ten years. This review, which is a novelty compared to published literature, will bring well documented and updated information to readers of Acta Biomaterialia. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Bacterial adhesion to orthopedic implant polymers.

PubMed

Barton, A J; Sagers, R D; Pitt, W G

1996-03-01

The degradable polymers poly(orthoester) (POE), poly(L-lactic acid) (PLA), and the nondegradable polymers polysulfone (PSF), polyethylene (PE), and poly(ether ether ketone) (PEEK) were exposed to cultures of Staphylococcus epidermidis, Pseudomonas aeruginosa, or Escherichia coli. Bacteria washed and resuspended in phosphate buffered saline (PBS) adhered to polymers in amounts nearly twice those of bacteria that were left in their growth medium, tryptic soy broth (TSB). In TSB, there was variation in adhesion from species to species, but no significant variation from polymer to polymer within one species. In PBS there were significant differences in the amounts of bacteria adhering to the various polymers with the exception, of S. epidermidis, which had similar adhesion to all polymers. As a whole, P. aeruginosa was the most adherent while S. epidermidis was the least adherent. The estimated values of the free energy of adhesion (delta Fadh) correlated with the amount of adherent P. aeruginosa. When POE, PLA, and PSF were exposed to hyaluronic acid (HA) before exposure to the bacteria, there was 50% more adhesion of E. coli and P. aeruginosa on POE and PLA. With respect to bacterial adhesion, the biodegradable polymers (POE and PLA) in general were not significantly different from the nondegradable polymers.

Flagellin based biomimetic coatings: From cell-repellent surfaces to highly adhesive coatings.

PubMed

Kovacs, Boglarka; Patko, Daniel; Szekacs, Inna; Orgovan, Norbert; Kurunczi, Sandor; Sulyok, Attila; Khanh, Nguyen Quoc; Toth, Balazs; Vonderviszt, Ferenc; Horvath, Robert

2016-09-15

Biomimetic coatings with cell-adhesion-regulating functionalities are intensively researched today. For example, cell-based biosensing for drug development, biomedical implants, and tissue engineering require that the surface adhesion of living cells is well controlled. Recently, we have shown that the bacterial flagellar protein, flagellin, adsorbs through its terminal segments to hydrophobic surfaces, forming an oriented monolayer and exposing its variable D3 domain to the solution. Here, we hypothesized that this nanostructured layer is highly cell-repellent since it mimics the surface of the flagellar filaments. Moreover, we proposed flagellin as a carrier molecule to display the cell-adhesive RGD (Arg-Gly-Asp) peptide sequence and induce cell adhesion on the coated surface. The D3 domain of flagellin was replaced with one or more RGD motifs linked by various oligopeptides modulating flexibility and accessibility of the inserted segment. The obtained flagellin variants were applied to create surface coatings inducing cell adhesion and spreading to different levels, while wild-type flagellin was shown to form a surface layer with strong anti-adhesive properties. As reference surfaces synthetic polymers were applied which have anti-adhesive (PLL-g-PEG poly(l-lysine)-graft-poly(ethylene glycol)) or adhesion inducing properties (RGD-functionalized PLL-g-PEG). Quantitative adhesion data was obtained by employing optical biochips and microscopy. Cell-adhesion-regulating coatings can be simply formed on hydrophobic surfaces by using the developed flagellin-based constructs. The developed novel RGD-displaying flagellin variants can be easily obtained by bacterial production and can serve as alternatives to create cell-adhesion-regulating biomimetic coatings. In the present work, we show for the first time that. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Role of bacterial adhesion in the microbial ecology of biofilms in cooling tower systems.

PubMed

Liu, Yang; Zhang, Wei; Sileika, Tadas; Warta, Richard; Cianciotto, Nicholas P; Packman, Aaron

2009-01-01

The fate of the three heterotrophic biofilm forming bacteria, Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. in pilot scale cooling towers was evaluated both by observing the persistence of each species in the recirculating water and the formation of biofilms on steel coupons placed in each cooling tower water reservoir. Two different cooling tower experiments were performed: a short-term study (6 days) to observe the initial bacterial colonization of the cooling tower, and a long-term study (3 months) to observe the ecological dynamics with repeated introduction of the test strains. An additional set of batch experiments (6 days) was carried out to evaluate the adhesion of each strain to steel surfaces under similar conditions to those found in the cooling tower experiments. Substantial differences were observed in the microbial communities that developed in the batch systems and cooling towers. P. aeruginosa showed a low degree of adherence to steel surfaces both in batch and in the cooling towers, but grew much faster than K. pneumoniae and Flavobacterium in mixed-species biofilms and ultimately became the dominant organism in the closed batch systems. However, the low degree of adherence caused P. aeruginosa to be rapidly washed out of the open cooling tower systems, and Flavobacterium became the dominant microorganism in the cooling towers in both the short-term and long-term experiments. These results indicate that adhesion, retention and growth on solid surfaces play important roles in the bacterial community that develops in cooling tower systems.

Role of bacterial adhesion in the microbial ecology of biofilms in cooling tower systems

PubMed Central

Liu, Yang; Zhang, Wei; Sileika, Tadas; Warta, Richard; Cianciotto, Nicholas P.; Packman, Aaron

2009-01-01

The fate of the three heterotrophic biofilm forming bacteria, Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. in pilot scale cooling towers was evaluated both by observing the persistence of each species in the recirculating water and the formation of biofilms on steel coupons placed in each cooling tower water reservoir. Two different cooling tower experiments were performed: a short-term study (6 days) to observe the initial bacterial colonization of the cooling tower, and a long-term study (3 months) to observe the ecological dynamics with repeated introduction of the test strains. An additional set of batch experiments (6 days) was carried out to evaluate the adhesion of each strain to steel surfaces under similar conditions to those found in the cooling tower experiments. Substantial differences were observed in the microbial communities that developed in the batch systems and cooling towers. P. aeruginosa showed a low degree of adherence to steel surfaces both in batch and in the cooling towers, but grew much faster than K. pneumoniae and Flavobacterium in mixed-species biofilms and ultimately became the dominant organism in the closed batch systems. However, the low degree of adherence caused P. aeruginosa to be rapidly washed out of the open cooling tower systems, and Flavobacterium became the dominant microorganism in the cooling towers in both the short-term and long-term experiments. These results indicate that adhesion, retention and growth on solid surfaces play important roles in the bacterial community that develops in cooling tower systems. PMID:19177226

Interference in adhesion of bacteria and yeasts isolated from explanted voice prostheses to silicone rubber by rhamnolipid biosurfactants.

PubMed

Rodrigues, L R; Banat, I M; van der Mei, H C; Teixeira, J A; Oliveira, R

2006-03-01

The effects and extent of adhesion of four different bacterial and two yeast strains isolated from explanted voice prostheses to silicone rubber with and without an adsorbed rhamnolipid biosurfactant layer obtained from Pseudomonasaeruginosa DS10-129 was studied. The ability of rhamnolipid biosurfactant to inhibit adhesion of micro-organisms to silicone rubber was investigated in a parallel-plate flow chamber. The anti-adhesive activity of the biosurfactant at different concentrations was significant against all the strains and depended on the micro-organism tested. The results showed an effective reduction in the initial deposition rates, and the number of bacterial cells adhering after 4 h, for all micro-organisms tested at the 4 g l(-1) undiluted rhamnolipid solution. Maximum initial reduction of adhesion rate (an average of 66%) occurred for Streptococcus salivarius GB 24/9 and Candida tropicalis GB 9/9. The number of cells adhering after 4 h on silicone rubber conditioned with biosurfactant was reduced to 48% for Staphylococcus epidermidis GB 9/6, Strep. salivarius GB 24/9, Staphylococcus aureus GB 2/1 and C. tropicalis GB 9/9 in comparison to controls. Perfusing the flow chamber with biosurfactant containing solution followed by the passage of a liquid-air interface, to investigate detachment of micro-organisms adhering to silicone rubber, produced high detachment (96%) of adhered cells for all micro-organisms studied, except for Staph. aureus GB 2/1 (67%). It is concluded that biosurfactant represent suitable compounds that should be considered in developing future strategies to prevent the microbial colonization of silicone rubber voice prostheses.

Bacterial self-defense antibiotics release from organic-inorganic hybrid multilayer films for long-term anti-adhesion and biofilm inhibition properties.

PubMed

Xu, Qingwen; Li, Xi; Jin, Yingying; Sun, Lin; Ding, Xiaoxu; Liang, Lin; Wang, Lei; Nan, Kaihui; Ji, Jian; Chen, Hao; Wang, Bailiang

2017-12-14

Implant-associated bacterial infections pose serious medical and financial issues due to the colonization and proliferation of pathogens on the surface of the implant. The as-prepared traditional antibacterial surfaces can neither resist bacterial adhesion nor inhibit the development of biofilm over the long term. Herein, novel (montmorillonite/poly-l-lysine-gentamicin sulfate) 8 ((MMT/PLL-GS) 8 ) organic-inorganic hybrid multilayer films were developed to combine enzymatic degradation PLL for on-demand self-defense antibiotics release. Small molecule GS was loaded into the multilayer films during self-assembly and the multilayer films showed pH-dependent and linear growth behavior. The chymotrypsin- (CMS) and bacterial infections-responsive film degradation led to the peeling of the films and GS release. Enzyme-responsive GS release exhibited CMS concentration dependence as measured by the size of the inhibition zone and SEM images. Notably, the obtained antibacterial films showed highly efficient bactericidal activity which killed more than 99.9% of S. aureus in 12 h. Even after 3 d of incubation in S. aureus, E. coli or S. epidermidis solutions, the multilayer films exhibited inhibition zones of more than 1.5 mm in size. Both in vitro and in vivo antibacterial tests indicated good cell compatibility, and anti-inflammatory, and long-term bacterial anti-adhesion and biofilm inhibition properties.

Role of F1C fimbriae, flagella, and secreted bacterial components in the inhibitory effect of probiotic Escherichia coli Nissle 1917 on atypical enteropathogenic E. coli infection.

PubMed

Kleta, Sylvia; Nordhoff, Marcel; Tedin, Karsten; Wieler, Lothar H; Kolenda, Rafal; Oswald, Sibylle; Oelschlaeger, Tobias A; Bleiss, Wilfried; Schierack, Peter

2014-05-01

Enteropathogenic Escherichia coli (EPEC) is recognized as an important intestinal pathogen that frequently causes acute and persistent diarrhea in humans and animals. The use of probiotic bacteria to prevent diarrhea is gaining increasing interest. The probiotic E. coli strain Nissle 1917 (EcN) is known to be effective in the treatment of several gastrointestinal disorders. While both in vitro and in vivo studies have described strong inhibitory effects of EcN on enteropathogenic bacteria, including pathogenic E. coli, the underlying molecular mechanisms remain largely unknown. In this study, we examined the inhibitory effect of EcN on infections of porcine intestinal epithelial cells with atypical enteropathogenic E. coli (aEPEC) with respect to single infection steps, including adhesion, microcolony formation, and the attaching and effacing phenotype. We show that EcN drastically reduced the infection efficiencies of aEPEC by inhibiting bacterial adhesion and growth of microcolonies, but not the attaching and effacing of adherent bacteria. The inhibitory effect correlated with EcN adhesion capacities and was predominantly mediated by F1C fimbriae, but also by H1 flagella, which served as bridges between EcN cells. Furthermore, EcN seemed to interfere with the initial adhesion of aEPEC to host cells by secretion of inhibitory components. These components do not appear to be specific to EcN, but we propose that the strong adhesion capacities enable EcN to secrete sufficient local concentrations of the inhibitory factors. The results of this study are consistent with a mode of action whereby EcN inhibits secretion of virulence-associated proteins of EPEC, but not their expression.

Evaluation of the antibacterial activity of a conventional orthodontic composite containing silver/hydroxyapatite nanoparticles.

PubMed

Sodagar, Ahmad; Akhavan, Azam; Hashemi, Ehsan; Arab, Sepideh; Pourhajibagher, Maryam; Sodagar, Kosar; Kharrazifard, Mohammad Javad; Bahador, Abbas

2016-12-01

One of the most important complications of fixed orthodontic treatment is the formation of white spots which are initial carious lesions. Addition of antimicrobial agents into orthodontic adhesives might be a wise solution for prevention of white spot formation. The aim of this study was to evaluate the antibacterial properties of a conventional orthodontic adhesive containing three different concentrations of silver/hydroxyapatite nanoparticles. One hundred and sixty-two Transbond XT composite discs containing 0, 1, 5, and 10 % silver/hydroxyapatite nanoparticles were prepared and sterilized. Antibacterial properties of these composite groups against Streptococcus mutans, Lactobacillus acidophilus, and Streptococcus sanguinis were investigated using three different antimicrobial tests. Disk agar diffusion test was performed to assess the diffusion of antibacterial agent on brain heart infusion agar plate by measuring bacterial growth inhibition zones. Biofilm inhibition test showed the antibacterial capacity of composite discs against resistant bacterial biofilms. Antimicrobial activity of eluted components from composite discs was investigated by comparing the viable counts of bacteria after 3, 15, and 30 days. Composite discs containing 5 and 10 % silver/hydroxyapatite nanoparticles were capable of producing growth inhibition zones for all bacterial types. Results of biofilm inhibition test showed that all of the study groups reduced viable bacterial count in comparison to the control group. Antimicrobial activity of eluted components from composite discs was immensely diverse based on the bacterial type and the concentration of nanoparticles. Transbond XT composite discs containing 5 and 10 % silver/hydroxyapatite nanoparticles produce bacterial growth inhibition zones and show antibacterial properties against biofilms.

Iron-Induced Virulence of Salmonella enterica Serovar Typhimurium at the Intestinal Epithelial Interface Can Be Suppressed by Carvacrol

PubMed Central

Kortman, Guus A. M.; Roelofs, Rian W. H. M.; Swinkels, Dorine W.; de Jonge, Marien I.; Burt, Sara A.

2014-01-01

Oral iron therapy can increase the abundance of bacterial pathogens, e.g., Salmonella spp., in the large intestine of African children. Carvacrol is a natural compound with antimicrobial activity against various intestinal bacterial pathogens, among which is the highly prevalent Salmonella enterica serovar Typhimurium. This study aimed to explore a presumed interaction between carvacrol and bacterial iron handling and to assess the potential of carvacrol in preventing the increase of bacterial pathogenicity during high iron availability. S. Typhimurium was cultured with increasing concentrations of iron and carvacrol to study the effects of these combined interventions on growth, adhesion to intestinal epithelial cells, and iron uptake/influx in both bacterial and epithelial cells. In addition, the ability of carvacrol to remove iron from the high-affinity ligand transferrin and an Fe-dye complex was examined. Carvacrol retarded growth of S. Typhimurium at all iron conditions. Furthermore, iron-induced epithelial adhesion was effectively reduced by carvacrol at high iron concentrations. The reduction of growth and virulence by carvacrol was not paralleled by a change in iron uptake or influx into S. Typhimurium. In contrast, bioavailability of iron for epithelial cells was moderately decreased under these conditions. Further, carvacrol was shown to lack the properties of an iron binding molecule; however, it was able to weaken iron-ligand interactions by which it may possibly interfere with bacterial virulence. In conclusion, our in vitro data suggest that carvacrol has the potential to serve as a novel dietary supplement to prevent pathogenic overgrowth and colonization in the large intestine during oral iron therapy. PMID:24379194

Attachment of Asaia bogorensis Originating in Fruit-Flavored Water to Packaging Materials

PubMed Central

Otlewska, Anna; Antolak, Hubert

2014-01-01

The objective of this study was to investigate the adhesion of isolated spoilage bacteria to packaging materials used in the food industry. Microorganisms were isolated from commercial fruit-flavored mineral water in plastic bottles with flocks as a visual defect. The Gram-negative rods were identified using the molecular method through the amplification of a partial region of the 16S rRNA gene. Based on the sequence identity (99.6%) between the spoilage organism and a reference strain deposited in GenBank, the spoilage isolate was identified as Asaia bgorensis. Experiments on bacterial adhesion were conducted using plates made of glass and polystyrene (packaging materials commonly used in the beverage industry). Cell adhesion ability was determined using luminometry, plate count, and the microscopic method. The strain of A. bogorensis was characterized by strong adhesion properties which were dependent on the surface type, with the highest cell adhesion detected on polystyrene. PMID:25295262

S. sanguinis adhesion on rough titanium surfaces: effect of culture media.

PubMed

Rodríguez-Hernández, Ana G; Muñoz-Tabares, José A; Godoy-Gallardo, Maria; Juárez, Antonio; Gil, Francisco-Javier

2013-03-01

Bacterial colonization plays a key role in dental implant failure, because they attach directly on implant surface upon implantation. Between different types of bacteria associated with the oral environment, Streptococcus sanguinis is essential in this process since it is an early colonizer. In this work the relationship between titanium surfaces modified by shot blasting treatment and S. sanguinis adhesion; have been studied in approached human mouth environment. Bacteria pre-inoculated with routinary solution were put in contact with titanium samples, shot-blasted with alumina and silicon carbide, and adhesion results were compared with those obtained when bacteria were pre-inoculated with modified artificial saliva medium and on saliva pre-coated titanium samples. Our results showed that bacterial adhesion on titanium samples was influenced by culture conditions. When S. sanguinis was inoculated in routinary culture media, colonies forming unities per square millimeter presented an increment correlated with roughness and surface energy, but separated by the type of particle used during shot-blasting treatment; whereas in modified artificial saliva only a relationship between bacteria adhered and the increment in both roughness and surface energy were observed, regardless of the particle type. Finally, on human saliva pre-coated samples no significant differences were observed among roughness, surface energy or particle. Copyright © 2012 Elsevier B.V. All rights reserved.

Impact of the exopolysaccharide layer on biofilms, adhesion and resistance to stress in Lactobacillus johnsonii FI9785.

PubMed

Dertli, Enes; Mayer, Melinda J; Narbad, Arjan

2015-02-04

The bacterial cell surface is a crucial factor in cell-cell and cell-host interactions. Lactobacillus johnsonii FI9785 produces an exopolysaccharide (EPS) layer whose quantity and composition is altered in mutants that harbour genetic changes in their eps gene clusters. We have assessed the effect of changes in EPS production on cell surface characteristics that may affect the ability of L. johnsonii to colonise the poultry host and exclude pathogens. Analysis of physicochemical cell surface characteristics reflected by Zeta potential and adhesion to hexadecane showed that an increase in EPS gave a less negative, more hydrophilic surface and reduced autoaggregation. Autoaggregation was significantly higher in mutants that have reduced EPS, indicating that EPS can mask surface structures responsible for cell-cell interactions. EPS also affected biofilm formation, but here the quantity of EPS produced was not the only determinant. A reduction in EPS production increased bacterial adhesion to chicken gut explants, but made the bacteria less able to survive some stresses. This study showed that manipulation of EPS production in L. johnsonii FI9785 can affect properties which may improve its performance as a competitive exclusion agent, but that positive changes in adhesion may be compromised by a reduction in the ability to survive stress.

Review on prevention of bacterial adhesion on contact lens using plasma treatment

NASA Astrophysics Data System (ADS)

Ramli, N. A. H.; Zaaba, S. K.; Mustaffa, M. T.; Zakaria, A.; Shahriman A., B.

2017-03-01

Many researches had been conducted to enhance the properties of contact lens. Most of the research conducted discussed on the factors that affect the adhesion process to contact lenses, rate of contact lens contamination, and type of microbe that adhere on the contact lens surface and contact lens casing. Studies on the proposed strategies or technology that can be used to slower down the formation of bacteria on contact lens are being explored. New technologies or strategies to prevent or slow down the adhesion of bacteria on contact lens have become a priority in this area. This review paper covers two main aspects, namely factor that affect the bacteria adhesion on contact lens and also the introduction of plasma treatment as a potential method for contact lens treatment.

Colloidal crystal based plasma polymer patterning to control Pseudomonas aeruginosa attachment to surfaces.

PubMed

Pingle, Hitesh; Wang, Peng-Yuan; Thissen, Helmut; McArthur, Sally; Kingshott, Peter

2015-12-02

Biofilm formation on medical implants and subsequent infections are a global problem. A great deal of effort has focused on developing chemical contrasts based on micro- and nanopatterning for studying and controlling cells and bacteria at surfaces. It has been known that micro- and nanopatterns on surfaces can influence biomolecule adsorption, and subsequent cell and bacterial adhesion. However, less focus has been on precisely controlling patterns to study the initial bacterial attachment mechanisms and subsequently how the patterning influences the role played by biomolecular adsorption on biofilm formation. In this work, the authors have used colloidal self-assembly in a confined area to pattern surfaces with colloidal crystals and used them as masks during allylamine plasma polymer (AAMpp) deposition to generate highly ordered patterns from the micro- to the nanoscale. Polyethylene glycol (PEG)-aldehyde was grafted to the plasma regions via "cloud point" grafting to prevent the attachment of bacteria on the plasma patterned surface regions, thereby controlling the adhesive sites by choice of the colloidal crystal morphology. Pseudomonas aeruginosa was chosen to study the bacterial interactions with these chemically patterned surfaces. Scanning electron microscope, x-ray photoelectron spectroscopy (XPS), atomic force microscopy, and epifluorescence microscopy were used for pattern characterization, surface chemical analysis, and imaging of attached bacteria. The AAMpp influenced bacterial attachment because of the amine groups displaying a positive charge. XPS results confirm the successful grafting of PEG on the AAMpp surfaces. The results showed that PEG patterns can be used as a surface for bacterial patterning including investigating the role of biomolecular patterning on bacterial attachment. These types of patterns are easy to fabricate and could be useful in further applications in biomedical research.

Nanoscale investigation on Pseudomonas aeruginosa biofilm formed on porous silicon using atomic force microscopy.

PubMed

Kannan, Ashwin; Karumanchi, Subbalakshmi Latha; Krishna, Vinatha; Thiruvengadam, Kothai; Ramalingam, Subramaniam; Gautam, Pennathur

2014-01-01

Colonization of surfaces by bacterial cells results in the formation of biofilms. There is a need to study the factors that are important for formation of biofilms since biofilms have been implicated in the failure of semiconductor devices and implants. In the present study, the adhesion force of biofilms (formed by Pseudomonas aeruginosa) on porous silicon substrates of varying surface roughness was quantified using atomic force microscopy (AFM). The experiments were carried out to quantify the effect of surface roughness on the adhesion force of biofilm. The results show that the adhesion force increased from 1.5 ± 0.5 to 13.2 ± 0.9 nN with increase in the surface roughness of silicon substrate. The results suggest that the adhesion force of biofilm is affected by surface roughness of substrate. © 2014 Wiley Periodicals, Inc.

Chromosomal Expression of the Haemophilus influenzae Hap Autotransporter Allows Fine-Tuned Regulation of Adhesive Potential via Inhibition of Intermolecular Autoproteolysis

PubMed Central

Fink, Doran L.; St. Geme III, Joseph W.

2003-01-01

The Haemophilus influenzae Hap autotransporter is a nonpilus adhesin that promotes adherence to respiratory epithelial cells and selected extracellular matrix proteins and facilitates bacterial aggregation and microcolony formation. Hap consists of a 45-kDa outer membrane translocator domain called Hapβ and a 110-kDa extracellular passenger domain called HapS. All adhesive activity resides within HapS, which also contains protease activity and directs its own secretion from the bacterial cell surface via intermolecular autoproteolysis. In the present study, we sought to determine the relationship between the magnitude of Hap expression, the efficiency of Hap autoproteolysis, and the level of Hap-mediated adherence and aggregation. We found that a minimum threshold of Hap precursor was required for autoproteolysis and that this threshold approximated expression of Hap from a chromosomal allele, as occurs in H. influenzae clinical isolates. Chromosomal expression of wild-type Hap was sufficient to promote significant adherence to epithelial cells and extracellular matrix proteins, and adherence was enhanced substantially by inhibition of autoproteolysis. In contrast, chromosomal expression of Hap was sufficient to promote bacterial aggregation only when autoproteolysis was inhibited, indicating that the threshold for Hap-mediated aggregation is above the threshold for autoproteolysis. These results highlight the critical role of autoproteolysis and an intermolecular mechanism of cleavage in controlling the diverse adhesive activities of Hap. PMID:12591878

Antibacterial and Antiadhesive Activities of Extracts from Edible Plants against Soft Drink Spoilage by Asaia spp.

PubMed

Antolak, Hubert; Czyzowska, Agata; Kregiel, Dorota

2017-01-01

This study was conducted to investigate the antibacterial and antiadhesive activities of ethanol extracts from five edible plant parts: cinnamon bark ( Cinnamomum zeylanicum ), licorice root ( Glycyrrhiza radix ), nettle leaves ( Urtica dioica ), green tea leaves ( Camellia sinensis ), and elderberry flowers ( Sambucus nigra ). The chemical constituents of the extracts were identified using high-performance liquid chromatography and liquid chromatography plus mass spectrometry. Six strains of Asaia lannensis and Asaia bogorensis bacteria isolated from spoiled commercial fruit-flavored noncarbonated mineral water were used. Bacterial adhesion to polystyrene as an attachment substrate in culture media supplemented with 10% plant extract was evaluated using luminometric measurement of the ATP extracted from adhered cells. The viability of the adhered and planktonic cells was assessed using the plate count method, and the relative adhesion coefficient was calculated. All tested crude extracts contained flavonols (kaempferol, quercetin, and their derivatives), flavanols (catechin and derivatives), flavanones (glabrol, licorice glycoside A, and liquiritin), and phenolic acids (gallic, quinic, chlorogenic, neochlorogenic, caffeic, coumaric, and ferulic). The culture medium with 10% elderberry extract provided the least favorable environment for all tested bacterial strains. Extracts from green tea, cinnamon, and licorice also had significant inhibitory effects on the adhesion of the tested bacterial strains. This research suggests that the addition of selected edible plant extracts could improve the microbial stability of noncarbonated soft drinks.

Surface Tension Mediated Under-Water Adhesion of Rigid Spheres on Soft, Charged Surfaces

NASA Astrophysics Data System (ADS)

Sinha, Shayandev; Das, Siddhartha

2015-11-01

Understanding the phenomenon of surface-tension-mediated under-water adhesion is necessary for studying a plethora of physiological and technical phenomena, such as the uptake of bacteria or nanoparticle by cells, attachment of virus on bacterial surfaces, biofouling on large ocean vessels and marine devices, etc. This adhesion phenomenon becomes highly non-trivial in case the soft surface where the adhesion occurs is also charged. Here we propose a theory for analyzing such an under-water adhesion of a rigid sphere on a soft, charged surface, represented by a grafted polyelectrolyte layer (PEL). We develop a model based on the minimization of free energy that, in addition to considering the elastic and the surface-tension-mediated adhesion energies, also accounts for the PEL electric double layer (EDL) induced electrostatic energies. We show that in the presence of surface charges, adhesion gets enhanced. This can be explained by the fact that the increase in the elastic energy is better balanced by the lowering of the EDL energy associated with the adhesion process. The entire behaviour is further dictated by the surface tension components that govern the adhesion energy.

The effects of nitric oxide in settlement and adhesion of zoospores of the green alga Ulva.

PubMed

Thompson, Stephanie E M; Callow, Maureen E; Callow, James A

2010-01-01

Previous studies have shown that elevated nitric oxide (NO) reduces adhesion in diatom, bacterial and animal cells. This article reports experiments designed to investigate whether elevated NO reduces the adhesion of zoospores of the green alga Ulva, an important fouling species. Surface-normalised values of NO were measured using the fluorescent indicator DAF-FM DA and parallel hydrodynamic measurements of adhesion strength were made. Elevated levels of NO caused by the addition of the exogenous NO donor SNAP reduced spore settlement by 20% and resulted in lower adhesion strength. Addition of the NO scavenger cPTIO abolished the effects of SNAP on adhesion. The strength of attachment and NO production by spores in response to four coatings (Silastic T2; Intersleek 700; Intersleek 900 and polyurethane) shows that reduced adhesion is correlated with an increase in NO production. It is proposed that in spores of Ulva, NO is used as an intracellular signalling molecule to detect how conducive a surface is for settlement and adhesion. The effect of NO on the adhesion of a range of organisms suggests that NO-releasing coatings could have the potential to control fouling.

The role of zeta potential in the adhesion of E. coli to suspended intertidal sediments.

PubMed

Wyness, Adam J; Paterson, David M; Defew, Emma C; Stutter, Marc I; Avery, Lisa M

2018-05-29

The extent of pathogen transport to and within aquatic systems depends heavily on whether the bacterial cells are freely suspended or in association with suspended particles. The surface charge of both bacterial cells and suspended particles affects cell-particle adhesion and subsequent transport and exposure pathways through settling and resuspension cycles. This study investigated the adhesion of Faecal Indicator Organisms (FIOs) to natural suspended intertidal sediments over the salinity gradient encountered at the transition zone from freshwater to marine environments. Phenotypic characteristics of three E. coli strains, and the zeta potential (surface charge) of the E. coli strains and 3 physically different types of intertidal sediments was measured over a salinity gradient from 0 to 5 Practical Salinity Units (PSU). A batch adhesion microcosm experiment was constructed with each combination of E. coli strain, intertidal sediment and 0, 2, 3.5 and 5 PSU. The zeta potential profile of one E. coli strain had a low negative charge and did not change in response to an increase in salinity, and the remaining E. coli strains and the sediments exhibited a more negative charge that decreased with an increase in salinity. Strain type was the most important factor in explaining cell-particle adhesion, however adhesion was also dependant on sediment type and salinity (2, 3.5 PSU > 0, 5 PSU). Contrary to traditional colloidal (Derjaguin, Landau, Vervey, and Overbeek (DLVO)) theory, zeta potential of strain or sediment did not correlate with cell-particle adhesion. E. coli strain characteristics were the defining factor in cell-particle adhesion, implying that diverse strain-specific transport and exposure pathways may exist. Further research applying these findings on a catchment scale is necessary to elucidate these pathways in order to improve accuracy of FIO fate and transport models. Copyright © 2018 Elsevier Ltd. All rights reserved.

Reduction in Thrombosis and Bacterial Adhesion with 7 Day Implantation of S-Nitroso-N-acetylpenicillamine (SNAP)-Doped Elast-eon E2As Catheters in Sheep

PubMed Central

Brisbois, Elizabeth J.; Davis, Ryan P.; Jones, Anna M.; Major, Terry C.; Bartlett, Robert H.; Meyerhoff, Mark E.; Handa, Hitesh

2015-01-01

Thrombosis and infection are two common problems associated with blood-contacting medical devices such as catheters. Nitric oxide (NO) is known to be a potent antimicrobial agent as well as an inhibitor of platelet activation and adhesion. Healthy endothelial cells that line the inner walls of all blood vessels exhibit a NO flux of 0.5~4×10−10 mol cm−2 min−1 that helps prevent thrombosis. Materials with a NO flux that is equivalent to this level are expected to exhibit similar anti-thrombotic properties. In this study, NO-releasing catheters were fabricated by incorporating S-nitroso-N-acetylpenicillamine (SNAP) in the Elast-eon E2As polymer. The SNAP/E2As catheters release physiological levels of NO for up to 20 d, as measured by chemiluminescence. Furthermore, SNAP is stable in the E2As polymer, retaining 89% of the initial SNAP after ethylene oxide (EO) sterilization. The SNAP/E2As and E2As control catheters were implanted in sheep veins for 7 d to examine the effect on thrombosis and bacterial adhesion. The SNAP/E2As catheters reduced the thrombus area when compared to the control (1.56 ± 0.76 and 5.06 ± 1.44 cm2, respectively). A 90% reduction in bacterial adhesion was also observed for the SNAP/E2As catheters as compared to the controls. The results suggest that the SNAP/E2As polymer has the potential to improve the hemocompatibility and bactericidal activity of intravascular catheters, as well as other blood-contacting medical devices (e.g., vascular grafts, extracorporeal circuits). PMID:25685358

Membrane cholesterol plays an important role in enteropathogen adhesion and the activation of innate immunity via flagellin-TLR5 signaling.

PubMed

Zhou, Mingxu; Duan, Qiangde; Li, Yinchau; Yang, Yang; Hardwidge, Philip R; Zhu, Guoqiang

2015-08-01

Lipid rafts are cholesterol- and sphingolipid-rich ordered microdomains distributed in the plasma membrane that participates in mammalian signal transduction pathways. To determine the role of lipid rafts in mediating interactions between enteropathogens and intestinal epithelial cells, membrane cholesterol was depleted from Caco-2 and IPEC-J2 cells using methyl-β-cyclodextrin. Cholesterol depletion significantly reduced Escherichia coli and Salmonella enteritidis adhesion and invasion into intestinal epithelial cells. Complementation with exogenous cholesterol restored bacterial adhesion to basal levels. We also evaluated the role of lipid rafts in the activation of Toll-like receptor 5 signaling by bacterial flagellin. Depleting membrane cholesterol reduced the ability of purified recombinant E. coli flagellin to activate TLR5 signaling in intestinal cells. These data suggest that both membrane cholesterol and lipid rafts play important roles in enteropathogen adhesion and contribute to the activation of innate immunity via flagellin-TLR5 signaling.

Non-invasive SFG spectroscopy: a tool to reveal the conformational change of grafted chains due to bacterial adhesion

NASA Astrophysics Data System (ADS)

Bulard, Emilie; Dubost, Henri; Fontaine-Aupart, Marie-Pierre; Zheng, Wanquan; Herry, Jean-Marie; Bellon-Fontaine, Marie-No"lle; Briandet, Romain; Bourguignon, Bernard

2011-07-01

In many fields such as biomedical or food industry, surface colonization by micro-organisms leads to biofilms formation that are tridimentional biostructures highly resistant to the action of antimicrobials, by mechanisms still unclear. In order to deepen our understanding of the initial interaction of bacteria cells with a solid surface, we analyze by in situ vibrational Sum Frequency Generation (SFG) spectroscopy the effect of the adhesion of hydrophilic Lactoccocus lactis bacteria and its hydrophobic mutants in distilled water on a self-assembled monolayer (SAM) of octadecanethiol (ODT) on a gold film. When a homogeneous bacterial monolayer is deposited on this ordered surface, SFG spectrum of the ODT SAM shows significant intensity changes from that in air or in water. Its modelling as a function of conformation allows to distinguish optical effects due to the water solution surrounding bacteria from conformational changes of the ODT SAM due to the presence of the bacteria cells. Futhermore, bacterial adhesion induces different measurable effects on the ODT SAM conformation, depending on the hydrophobic / hydrophilic character of the bacterial surface. Such a result deserves to be taken into account for the design of new materials with improved properties or to control biofilm formation.

Microflora on explanted silicone rubber voice prostheses: taxonomy, hydrophobicity and electrophoretic mobility.

PubMed

Neu, T R; Verkerke, G J; Herrmann, I F; Schutte, H K; Van der Mei, H C; Busscher, H J

1994-05-01

Silicone rubber voice prostheses are implants which are inserted in a non-sterile environment and therefore become quickly colonized by micro-organisms. The micro-organisms exist on the medical grade silicone rubber as mixed biofilms of bacteria and yeasts. A total of 79 bacterial and 39 yeast strains were isolated from these biofilms by soft ultrasonic treatment. Gram-positive/catalase-negative and Gram-positive/catalase-positive cocci represented the dominant bacterial strains. The yeasts were mainly Candida species. Further characterization of cell surface properties such as hydrophobicity by microbial adhesion to hexadecane and electrophoretic mobility showed a distinct difference when the bacterial strains were compared with the yeasts. The bacterial hydrophobicities ranged from 0 to 100% adhesion to hexadecane, whereas the yeast strains, especially the Candida albicans strains, all had markedly hydrophilic cell surfaces. A comparison of the electrophoretic mobilities showed also differences between bacteria and yeast. The values for the bacteria were found to be between -2.5 to -0.5 (10(-8) m2 V-1 s-1), whereas for the yeasts electrophoretic mobilities were more positive. Based on the adhesive properties of the isolated micro-organisms, strategies can now be developed to modify the properties of the silicone rubber to reduce biofilm formation on such prostheses.

An in vitro atomic force microscopic study of commercially available dental luting materials.

PubMed

Djordje, Antonijevic; Denis, Brajkovic; Nenadovic, Milos; Petar, Milovanovic; Marija, Djuric; Zlatko, Rakocevic

2013-09-01

The aim of this in vitro study was to compare the surface roughness parameters of four different types of dental luting agents used for cementation of implant restorations. Five specimens (8 mm high and 1 mm thick) of each cement were made using metal ring steelless molds. Atomic Force Microscope was employed to analyze different surface texture parameters of the materials. Bearing ratio analysis was used to calculate the potential microgap size between the cement and implant material and to calculate the depth of the valleys on the cement surface, while power spectral density (PSD) measurements were performed to measure the percentage of the surface prone to bacterial adhesion. Glass ionomer cement showed significantly lower value of average surface roughness then the other groups of the materials (P < 0.05) which was in line with the results of Bearing ratio analysis. On the other side, PSD analysis showed that zinc phosphate cement experience the lowest percentage of the surface which promote bacterial colonization. Glas ionomer cements present the surface roughness parameters that are less favorable for bacterial adhesion than that of zinc phosphate, resin-modified glass ionomer and resin cements. Copyright © 2013 Wiley Periodicals, Inc.

Bacterial Extracellular Polysaccharides in Biofilm Formation and Function

PubMed Central

Limoli, Dominique H.; Jones, Christopher J.; Wozniak, Daniel J.

2015-01-01

Microbes produce a biofilm matrix consisting of proteins, extracellular DNA, and polysaccharides that is integral in the formation of bacterial communities. Historical studies of polysaccharides revealed that their overproduction often alters the colony morphology and can be diagnostic in identifying certain species. The polysaccharide component of the matrix can provide many diverse benefits to the cells in the biofilm, including adhesion, protection, and structure. Aggregative polysaccharides act as molecular glue, allowing the bacterial cells to adhere to each other as well as surfaces. Adhesion facilitates the colonization of both biotic and abiotic surfaces by allowing the bacteria to resist physical stresses imposed by fluid movement that could separate the cells from a nutrient source. Polysaccharides can also provide protection from a wide range of stresses, such as desiccation, immune effectors, and predators such as phagocytic cells and amoebae. Finally, polysaccharides can provide structure to biofilms, allowing stratification of the bacterial community and establishing gradients of nutrients and waste products. This can be advantageous for the bacteria by establishing a heterogeneous population that is prepared to endure stresses created by the rapidly changing environments that many bacteria encounter. The diverse range of polysaccharide structures, properties, and roles highlight the importance of this matrix constituent to the successful adaptation of bacteria to nearly every niche. Here, we present an overview of the current knowledge regarding the diversity and benefits that polysaccharide production provides to bacterial communities within biofilms. PMID:26185074

Bacterial Extracellular Polysaccharides in Biofilm Formation and Function.

PubMed

Limoli, Dominique H; Jones, Christopher J; Wozniak, Daniel J

2015-06-01

Microbes produce a biofilm matrix consisting of proteins, extracellular DNA, and polysaccharides that is integral in the formation of bacterial communities. Historical studies of polysaccharides revealed that their overproduction often alters the colony morphology and can be diagnostic in identifying certain species. The polysaccharide component of the matrix can provide many diverse benefits to the cells in the biofilm, including adhesion, protection, and structure. Aggregative polysaccharides act as molecular glue, allowing the bacterial cells to adhere to each other as well as surfaces. Adhesion facilitates the colonization of both biotic and abiotic surfaces by allowing the bacteria to resist physical stresses imposed by fluid movement that could separate the cells from a nutrient source. Polysaccharides can also provide protection from a wide range of stresses, such as desiccation, immune effectors, and predators such as phagocytic cells and amoebae. Finally, polysaccharides can provide structure to biofilms, allowing stratification of the bacterial community and establishing gradients of nutrients and waste products. This can be advantageous for the bacteria by establishing a heterogeneous population that is prepared to endure stresses created by the rapidly changing environments that many bacteria encounter. The diverse range of polysaccharide structures, properties, and roles highlight the importance of this matrix constituent to the successful adaptation of bacteria to nearly every niche. Here, we present an overview of the current knowledge regarding the diversity and benefits that polysaccharide production provides to bacterial communities within biofilms.

A facile bacterial assisted electrochemical self-assembly of polypyrrole micro-pillars: towards underwater low adhesive superoleophobicity

NASA Astrophysics Data System (ADS)

Cheng, Zhe; Ding, Chunmei; Liu, Huan; Zhu, Ying; Jiang, Lei

2013-12-01

By taking advantage of bacterial extracellular electron transfer behavior, a facile method was developed to fabricate oriented polypyrrole micro-pillars (PPy-MP) with nanoscale surface roughness. Microbes acted as a living conductive template on which PPy was in situ polymerized. The as-prepared PPy-MP exhibit the distinctive underwater low adhesive superoleophobicity which is attributable to the unique hierarchical micro/nano-structures and the high surface energy by doping with inorganic small anions.By taking advantage of bacterial extracellular electron transfer behavior, a facile method was developed to fabricate oriented polypyrrole micro-pillars (PPy-MP) with nanoscale surface roughness. Microbes acted as a living conductive template on which PPy was in situ polymerized. The as-prepared PPy-MP exhibit the distinctive underwater low adhesive superoleophobicity which is attributable to the unique hierarchical micro/nano-structures and the high surface energy by doping with inorganic small anions. Electronic supplementary information (ESI) available: The shape of a water drop on PPy-MPA and cauliflower-like PPy film in air. See DOI: 10.1039/c3nr03788f

Action of Monomeric/Gemini Surfactants on Free Cells and Biofilm of Asaia lannensis.

PubMed

Koziróg, Anna; Kręgiel, Dorota; Brycki, Bogumił

2017-11-22

We investigated the biological activity of surfactants based on quaternary ammonium compounds: gemini surfactant hexamethylene-1,6-bis-( N,N -dimethyl- N -dodecylammonium bromide) (C6), synthesized by the reaction of N,N -dimethyl- N- dodecylamine with 1,6-dibromohexane, and its monomeric analogue dodecyltrimethylammonium bromide (DTAB). The experiments were performed with bacteria Asaia lannensis , a common spoilage in the beverage industry. The minimal inhibitory concentration (MIC) values were determined using the tube standard two-fold dilution method. The growth and adhesive properties of bacterial cells were studied in different culture media, and the cell viability was evaluated using plate count method. Both of the surfactants were effective against the bacterial strain, but the MIC of gemini compound was significantly lower. Both C6 and DTAB exhibited anti-adhesive abilities. Treatment with surfactants at or below MIC value decreased the number of bacterial cells that were able to form biofilm, however, the gemini surfactant was more effective. The used surfactants were also found to be able to eradicate mature biofilms. After 4 h of treatment with C6 surfactant at concentration 10 MIC, the number of bacterial cells was reduced by 91.8%. The results of this study suggest that the antibacterial activity of the gemini compound could make it an effective microbiocide against the spoilage bacteria Asaia sp. in both planktonic and biofilm stages.

Lectin I from Bauhinia variegata (BVL-I) expressed by Pichia pastoris inhibits initial adhesion of oral bacteria in vitro.

PubMed

Klafke, Gabriel Baracy; Moreira, Gustavo Marçal Schmidt Garcia; Pereira, Juliano Lacava; Oliveira, Patrícia Diaz; Conceição, Fabricio Rochedo; Lund, Rafael Guerra; Grassmann, André Alex; Dellagostin, Odir Antonio; da Silva Pinto, Luciano

2016-12-01

Lectins are non-immune proteins that reversibly bind to carbohydrates in a specific manner. Bauhinia variegata lectin I (BVL-I) is a Gal/GalNAc-specific, single-chain lectin isolated from Bauhinia variegata seeds that has been implicated in the inhibition of bacterial adhesion and the healing of damaged skin. Since the source of the native protein (nBVL) is limited, this study aimed to produce recombinant BVL-I in Pichia pastoris (rBVL-Ip). The coding sequence for BVL-I containing preferential codons for P. pastoris was cloned into the pPICZαB plasmid. A single expressing clone was selected and fermented, resulting in the secretion and glycosylation of the protein. Fed-batch fermentation in 7L-scale was performed, and the recombinant lectin was purified from culture supernatant, resulting in a yield of 1.5mg/L culture. Further, rBVL-Ip was compared to nBVL and its recombinant version expressed in Escherichia coli BL21 (DE3) (rBVL-Ie). Although it was expressed as a monomer, rBVL-Ip retained its biological activity since it was able to impair the initial adhesion of Streptococcus mutans and S. sanguinis in an in vitro model of biofilm formation and bacterial adhesion. In summary, rBVL-Ip produced in Pichia pastoris represents a viable alternative to large-scale production, encouraging further biological application studies with this lectin. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface adhesion and confinement variation of Staphylococcus aurius on SAM surfaces

NASA Astrophysics Data System (ADS)

Amroski, Alicia; Olsen, Morgan; Calabrese, Joseph; Senevirathne, Reshani; Senevirathne, Indrajith

2012-02-01

Controlled surface adhesion of non - pathogenic gram positive strain, Staphylococcus aureus is interesting as a model system due to possible development of respective biosensors for prevention and detection of the pathogenic strain methicillin resistant Staphylococcus aureus (MRSA) and further as a study for bio-machine interfacing. Self Assembled Monolayers (SAM) with engineered surfaces of linear thiols on Au(111) were used as the substrate. Sub cultured S. aureus were used for the analysis. The SAM layered surfaces were dipped in 2 -- 4 Log/ml S. aureus solution. Subsequent surface adhesion at different bacterial dilutions on surfaces will be discussed, and correlated with quantitative and qualitative adhesion properties of bacteria on the engineered SAM surfaces. The bacteria adhered SAM surfaces were investigated using intermittent contact, noncontact, lateral force and contact modes of Atomic Force Microscopy (AFM).

Adhesion by pathogenic corynebacteria.

PubMed

Rogers, Elizabeth A; Das, Asis; Ton-That, Hung

2011-01-01

Pathogenic members of the genus Corynebacterium cause a wide range of serious infections in humans including diphtheria. Adhesion to host cells is a crucial step during infection. In Corynebacterium diphtheriae, adhesion is mediated primarily by filamentous structures called pili or fimbriae that are covalently attached to the bacterial cell wall. C. diphtheriae produces three distinct pilus structures, SpaA-, SpaD- and SpaH-type pili. Similar to other types, the prototype SpaA pilus consists of SpaA forming the pilus shaft and two minor pilins SpaB and SpaC located at the base and at the tip, respectively. The minor pilins SpaB/SpaC are critical for bacterial binding to human pharyngeal cells, and thus represent the major adhesins of corynebacteria. Like pili of many other gram-positive microbes, the assembly of corynebacterial pili occurs by a two-step mechanism, whereby pilins are covalently polymerized by a transpeptidase enzyme named pilin-specific sortase and the generated pilus polymer is subsequently anchored to the cell wall peptidoglycan via the base pilin by the housekeeping sortase or a non-polymerizing sortase. This chapter reviews the current knowledge of corynebacterial adhesion, with a specific focus on pilus structures, their assembly, and the mechanism of adhesion mediated by pili.

In vitro anti-bacterial and anti-adherence effects of Lactobacillus delbrueckii subsp bulgaricus on Escherichia coli

PubMed Central

Abedi, D.; Feizizadeh, S.; Akbari, V.; Jafarian-Dehkordi, A.

2013-01-01

Considering the emergence of antibiotic resistance, scientists are interested in using new antimicrobial agents in the treatment of infectious diseases including infections of the enteric systems. Lactic acid bacteria have the great potential to produce antimicrobial compounds that inhibit and control pathogenic bacteria. The aim of this study was to determine the anti-bacterial and anti-adherence properties of Lactobacillus delbrueckii subsp bulgaricus against Escherichia coli. The antibacterial activity of L. delbrueckii was investigated using disc diffusion and spot on lawn methods. In vitro anti-adhesion effect of L. delbrueckii against E. coli was examined using Caco-2 cells. In anti-adhesion assay, three competition conditions including competitive inhibition, adhesion inhibition, and displacement were examined. In spot on lawn method the zone of growth inhibition of E. coli by L. delbrueckii was 21.1 mm. The cell free supernatant of L. delbrueckii showed a good antibacterial activity against E. coli which was mainly related to lactic acid produced by L. delbrueckii. When two bacteria added simultaneously (competitive inhibition) degree of inhibition of E. coli binding by L. delbrueckii was 77%. In adhesion inhibition assay, L. delbrueckii was able to exclude E. coli adherence by around 43.5%. Displacement assay showed that L. delbrueckii had strong displacement ability toward E. coli and reduction of E. coli attachment by bound L. delbrueckii was 81.3%. The results suggest that L. delbrueckii may be able to inhibit E. coli infection in the gut; however more studies including in vivo studies need to be performed. PMID:24082895

In vitro anti-bacterial and anti-adherence effects of Lactobacillus delbrueckii subsp bulgaricus on Escherichia coli.

PubMed

Abedi, D; Feizizadeh, S; Akbari, V; Jafarian-Dehkordi, A

2013-10-01

Considering the emergence of antibiotic resistance, scientists are interested in using new antimicrobial agents in the treatment of infectious diseases including infections of the enteric systems. Lactic acid bacteria have the great potential to produce antimicrobial compounds that inhibit and control pathogenic bacteria. The aim of this study was to determine the anti-bacterial and anti-adherence properties of Lactobacillus delbrueckii subsp bulgaricus against Escherichia coli. The antibacterial activity of L. delbrueckii was investigated using disc diffusion and spot on lawn methods. In vitro anti-adhesion effect of L. delbrueckii against E. coli was examined using Caco-2 cells. In anti-adhesion assay, three competition conditions including competitive inhibition, adhesion inhibition, and displacement were examined. In spot on lawn method the zone of growth inhibition of E. coli by L. delbrueckii was 21.1 mm. The cell free supernatant of L. delbrueckii showed a good antibacterial activity against E. coli which was mainly related to lactic acid produced by L. delbrueckii. When two bacteria added simultaneously (competitive inhibition) degree of inhibition of E. coli binding by L. delbrueckii was 77%. In adhesion inhibition assay, L. delbrueckii was able to exclude E. coli adherence by around 43.5%. Displacement assay showed that L. delbrueckii had strong displacement ability toward E. coli and reduction of E. coli attachment by bound L. delbrueckii was 81.3%. The results suggest that L. delbrueckii may be able to inhibit E. coli infection in the gut; however more studies including in vivo studies need to be performed.

High Throughput Assay for Bacterial Adhesion on Acellular Dermal Matrices and Synthetic Surgical Materials

PubMed Central

Nyame, Theodore T.; Lemon, Katherine P.; Kolter, Roberto; Liao, Eric C.

2013-01-01

Background There has been increasing use of various synthetic and biologically derived materials in surgery. Biologic surgical materials are used in many plastic surgery procedures, ranging from breast reconstruction to hernia repairs. In particular, acellular dermal matrix (ADM) material has gained popularity in these applications. There is a paucity of data on how ADM compares to other surgical materials as a substrate for bacterial adhesion, the first step in formation biofilm, which occurs in prosthetic wound infections. We have designed a high throughput assay to evaluate Staphylococcus aureus adherence on various synthetic and biologically derived materials. Methods Clinical isolates of Staphylococcus aureus (strains SC-1 and UAMS-1) were cultured with different materials and bacterial adherence was measured using a resazurin cell vitality reporter microtiter assay. Four materials that are commonly utilized in reconstructive procedures were evaluated: prolene mesh, vicryl mesh, and two different ADM preparations (AlloDerm®, FlexHD®). We were able to develop a high throughput and reliable assay for quantifying bacterial adhesion on synthetic and biologically derived materials. Results The resazurin vitality assay can be reliably used to quantify bacterial adherence to acellular dermal matrix material, as well as synthetic material. S. aureus strains SC-1 and UAMS-1 both adhered better to ADM materials (AlloDerm® vs. FlexHD®) than to the synthetic material prolene. S. aureus also adhered better to vicryl than to prolene. Strain UAMS-1 adhered better to vicryl and ADM materials than did strain SC-1. Conclusion Our results suggest that S. aureus adheres more readily to ADM material than to synthetic material. We have developed an assay to rapidly test bacterial formation on surgical materials, using two S. aureus bacterial strains. This provides a standard method to evaluate existing and new materials with regard to bacterial adherence and potential propensity for infection. This assay is particularly important in the clinical context of the severe sequelae of post-operative infection. PMID:22030489

In Vitro Adhesion of Streptococcus sanguinis to Dentine Root Surface After Treatment with Er:Yag Laser, Ultrasonic System, or Manual Curette

PubMed Central

Martins, Fernanda L.; Giorgetti, Ana Paula O.; de Freitas, Patrícia M.; Duarte, Poliana M.

2009-01-01

Abstract Objective: The purpose of this in vitro study was to evaluate the dentine root surface roughness and the adherence of Streptococcus sanguinis (ATCC 10556) after treatment with an ultrasonic system, Er:YAG laser, or manual curette. Background Data: Bacterial adhesion and formation of dental biofilm after scaling and root planing may be a challenge to the long-term stability of periodontal therapy. Materials and Methods: Forty flattened bovine roots were randomly assigned to one of the following groups: ultrasonic system (n = 10); Er:YAG laser (n = 10); manual curette (n = 10); or control untreated roots (n = 10). The mean surface roughness (Ra, μm) of the specimens before and after exposure to each treatment was determined using a surface profilometer. In addition, S. sanguinis was grown on the treated and untreated specimens and the amounts of retained bacteria on the surfaces were measured by culture method. Results: All treatments increased the Ra; however, the roughest surface was produced by the curettes. In addition, the specimens treated with curettes showed the highest S. sanguinis adhesion. There was a significant positive correlation between roughness values and bacterial cells counts. Conclusion: S. sanguinis adhesion was the highest on the curette-treated dentine root surfaces, which also presented the greatest surface roughness. PMID:19712018

Semiquantitative Performance and Mechanism Evaluation of Carbon Nanomaterials as Cathode Coatings for Microbial Fouling Reduction.

PubMed

Zhang, Qiaoying; Nghiem, Joanne; Silverberg, Gregory J; Vecitis, Chad D

2015-07-01

In this study, we examine bacterial attachment and survival on a titanium (Ti) cathode coated with various carbon nanomaterials (CNM): pristine carbon nanotubes (CNT), oxidized carbon nanotubes (O-CNT), oxidized-annealed carbon nanotubes (OA-CNT), carbon black (CB), and reduced graphene oxide (rGO). The carbon nanomaterials were dispersed in an isopropyl alcohol-Nafion solution and were then used to dip-coat a Ti substrate. Pseudomonas fluorescens was selected as the representative bacterium for environmental biofouling. Experiments in the absence of an electric potential indicate that increased nanoscale surface roughness and decreased hydrophobicity of the CNM coating decreased bacterial adhesion. The loss of bacterial viability on the noncharged CNM coatings ranged from 22% for CB to 67% for OA-CNT and was dependent on the CNM dimensions and surface chemistry. For electrochemical experiments, the total density and percentage of inactivation of the adherent bacteria were analyzed semiquantitatively as functions of electrode potential, current density, and hydrogen peroxide generation. Electrode potential and hydrogen peroxide generation were the dominant factors with regard to short-term (3-h) bacterial attachment and inactivation, respectively. Extended-time electrochemical experiments (12 h) indicated that in all cases, the density of total deposited bacteria increased almost linearly with time and that the rate of bacterial adhesion was decreased 8- to 10-fold when an electric potential was applied. In summary, this study provides a fundamental rationale for the selection of CNM as cathode coatings and electric potential to reduce microbial fouling. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

[Cranberry (Vaccinium macrocarpon) and urinary tract infections: study model and review of literature].

PubMed

Lavigne, J-P; Bourg, G; Botto, H; Sotto, A

2007-11-01

Cranberries (Vaccinium macrocarpon) have long been the focus of interest for their beneficial effects in preventing urinary tract infections. Among cranberry compounds, a group of proanthocyanidins (PACs) with A-type linkages were isolated which exhibit bacterial anti-adhesion activity against uropathogenic Escherichia coli strains. These PAC inhibit P-fimbriae synthesis and induce a bacterial deformation. This activity was demonstrated on both antibiotic susceptible and resistant bacteria. This review focused on the last discoveries in the knowledge of cranberry effects.

Functional analysis of alpha5beta1 integrin and lipid rafts in invasion of epithelial cells by Porphyromonas gingivalis using fluorescent beads coated with bacterial membrane vesicles.

PubMed

Tsuda, Kayoko; Furuta, Nobumichi; Inaba, Hiroaki; Kawai, Shinji; Hanada, Kentaro; Yoshimori, Tamotsu; Amano, Atsuo

2008-01-01

Porphyromonas gingivalis, a periodontal pathogen, was previously suggested to exploit alpha5beta1 integrin and lipid rafts to invade host cells. However, it is unknown if the functional roles of these host components are distinct from one another during bacterial invasion. In the present study, we analyzed the mechanisms underlying P. gingivalis invasion, using fluorescent beads coated with bacterial membrane vesicles (MV beads). Cholesterol depletion reagents including methyl-beta-cyclodextrin (MbetaCD) drastically inhibited the entry of MV beads into epithelial cells, while they were less effective on bead adhesion to the cells. Bead entry was also abolished in CHO cells deficient in sphingolipids, components of lipid rafts, whereas adhesion was negligibly influenced. Following MbetaCD treatment, downstream events leading to actin polymerization were abolished; however, alpha5beta1 integrin was recruited to beads attached to the cell surface. Dominant-negative Rho GTPase Rac1 abolished cellular engulfment of the beads, whereas dominant-negative Cdc42 did not. Following cellular interaction with the beads, Rac1 was found to be translocated to the lipid rafts fraction, which was inhibited by MbetaCD. These results suggest that alpha5beta1 integrin, independent of lipid rafts, promotes P. gingivalis adhesion to epithelial cells, while the subsequent uptake process requires lipid raft components for actin organization, with Rho GTPase Rac1.

Adhesive capability of Lactobacillus plantarum 299v is important for preventing bacterial translocation in endotoxemic rats.

PubMed

Mangell, Peter; Lennernäs, Pernilla; Wang, Mei; Olsson, Crister; Ahrné, Siv; Molin, Göran; Thorlacius, Henrik; Jeppsson, Bengt

2006-09-01

The preventive effect of the probiotic Lactobacillus plantarum 299v on bacterial translocation (BT) and the role of adhesion were studied in septic rats. Five groups of rats were pretreated as follows: negative and positive control groups received regular drinking water; the oatmeal group received drinking water mixed with oatmeal; the Lp 299v group received drinking water mixed with oatmeal containing 10(9) colony-forming units (CFU) L. plantarum 299v/ml; the Lp 299v-adh(-) group received drinking water with oatmeal containing 10(9) CFU/ml of modified L. plantarum 299v (L. plantarum 299v-adh(-)) lacking adhesive properties to enterocytes. On day 8, all rats except the negative control group were given lipopolysaccharide (LPS) intraperitoneally. After 24 h, mesenteric lymph node (MLN), liver and ileum were harvested for culture. Incidence of BT after LPS challenge was 25% and 88% in MLN and liver, respectively. BT increased to 75% in MLN and 100% in liver of endotoxemic rats pretreated with oatmeal. Pretreatment with L. plantarum 299v reduced BT to 0% and 12% in MLN and liver, respectively. L. plantarum 299v-adh(-) did not prevent BT to MLN. Flow cytometry revealed reduced adherence of these bacteria to intestinal epithelial cells compared to L. plantarum 299v. Thus, L. plantarum 299v prevents BT in septic rats, an effect probably dependent on bacterial adherence to the intestinal mucosa. Further, our findings indicate that oatmeal (prebiotics) without probiotics does not prevent BT during sepsis.

Carbon fibers with a nano-hydroxyapatite coating as an excellent biofilm support for bioreactors

NASA Astrophysics Data System (ADS)

Liu, Qijie; Zhang, Chao; Bao, Yanling; Dai, Guangze

2018-06-01

A biofilm support with high biocompatibility is needed for bioreactors. A nano-hydroxyapatite (HA) coating on carbon fibers (CFs) was prepared by electrochemical deposition (ECD). The sludge immobilization assays, bacterial cells adhesion assays and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory were used to evaluate the capacity of CF supports to immobilize activated sludge and bacterial cells. The sludge immobilization and bacterial cells adhesion assays illustrated that HA coating could enhance the capacity of CFs to immobilize microorganisms. SEM images showed that HA and bacterial cells formed a dense film on CFs surface. In addition, HA, acting as a glue, could combine CFs with bacterial cells or between cells, which helped CFs capture more bacterial cells. DLVO theory illustrated that CFs with HA coating had a lower total interaction energy than CFs without handling, explaining the higher capacity of CFs with HA coating to immobilize bacterial cells. This result was owning to the less negative zeta potential and higher hydrophilicity of CFs with HA coating, and the hydrophilicity made a greater contribution to the lower total interaction energy. Experiments and theory reveal that HA coating could enhance the biocompatibility of CFs, and CFs with HA coating could be used as an excellent biofilm support for bioreactors.

Antimicrobial activity of a novel adhesive containing chlorhexidine gluconate (CHG) against the resident microflora in human volunteers

PubMed Central

Carty, Neal; Wibaux, Anne; Ward, Colleen; Paulson, Daryl S.; Johnson, Peter

2014-01-01

Objectives To evaluate the antimicrobial activity of a new, transparent composite film dressing, whose adhesive contains chlorhexidine gluconate (CHG), against the native microflora present on human skin. Methods CHG-containing adhesive film dressings and non-antimicrobial control film dressings were applied to the skin on the backs of healthy human volunteers without antiseptic preparation. Dressings were removed 1, 4 or 7 days after application. The bacterial populations underneath were measured by quantitative cultures (cylinder-scrub technique) and compared with one another as a function of time. Results The mean baseline microflora recovery was 3.24 log10 cfu/cm2. The mean log reductions from baseline measured from underneath the CHG-containing dressings were 0.87, 0.78 and 1.30 log10 cfu/cm2 on days 1, 4 and 7, respectively, compared with log reductions of 0.67, −0.87 and −1.29 log10 cfu/cm2 from underneath the control film dressings. There was no significant difference between the log reductions of the two treatments on day 1, but on days 4 and 7 the log reduction associated with the CHG adhesive was significantly higher than that associated with the control adhesive. Conclusions The adhesive containing CHG was associated with a sustained antimicrobial effect that was not present in the control. Incorporating the antimicrobial into the adhesive layer confers upon it bactericidal properties in marked contrast to the non-antimicrobial adhesive, which contributed to bacterial proliferation when the wear time was ≥4 days. PMID:24722839

Antimicrobial activity of a novel adhesive containing chlorhexidine gluconate (CHG) against the resident microflora in human volunteers.

PubMed

Carty, Neal; Wibaux, Anne; Ward, Colleen; Paulson, Daryl S; Johnson, Peter

2014-08-01

To evaluate the antimicrobial activity of a new, transparent composite film dressing, whose adhesive contains chlorhexidine gluconate (CHG), against the native microflora present on human skin. CHG-containing adhesive film dressings and non-antimicrobial control film dressings were applied to the skin on the backs of healthy human volunteers without antiseptic preparation. Dressings were removed 1, 4 or 7 days after application. The bacterial populations underneath were measured by quantitative cultures (cylinder-scrub technique) and compared with one another as a function of time. The mean baseline microflora recovery was 3.24 log10 cfu/cm(2). The mean log reductions from baseline measured from underneath the CHG-containing dressings were 0.87, 0.78 and 1.30 log10 cfu/cm(2) on days 1, 4 and 7, respectively, compared with log reductions of 0.67, -0.87 and -1.29 log10 cfu/cm(2) from underneath the control film dressings. There was no significant difference between the log reductions of the two treatments on day 1, but on days 4 and 7 the log reduction associated with the CHG adhesive was significantly higher than that associated with the control adhesive. The adhesive containing CHG was associated with a sustained antimicrobial effect that was not present in the control. Incorporating the antimicrobial into the adhesive layer confers upon it bactericidal properties in marked contrast to the non-antimicrobial adhesive, which contributed to bacterial proliferation when the wear time was ≥4 days. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.

Effect of oligosaccharides on the adhesion of gut bacteria to human HT-29 cells.

PubMed

Altamimi, M; Abdelhay, O; Rastall, R A

2016-06-01

The influence of five oligosaccharides (cellobiose, stachyose, raffinose, lactulose and chito-oligosaccharides) on the adhesion of eight gut bacteria (Bifidobacterium bifidum ATCC 29521, Bacteroides thetaiotaomicron ATCC 29148D-5, Clostridium leptum ATCC 29065, Blautia coccoides ATCC 29236, Faecalibacterium prausnitzii ATCC 27766, Bacteroides fragilis ATCC 23745, Clostridium difficile ATCC 43255 and Lactobacillus casei ATCC 393) to mucous secreting and non-mucous secreting HT-29 human epithelial cells, was investigated. In pure culture, the bacteria showed variations in their ability to adhere to epithelial cells. The effect of oligosaccharides diminished adhesion and the presence of mucus played a major factor in adhesion, likely due to high adhesiveness to mucins present in the native human mucus layer covering the whole cell surface. However, clostridia displayed almost the same level of adhesion either with or without mucus being present. Bl. coccoides adhesion was decreased by stachyose and cellobiose in non-mucus-secreting cells in pure culture, while in mixed faecal culture cellobiose displayed the highest antiadhesive activity with an overall average of 65% inhibition amongst tested oligomers and lactulose displayed the lowest with an average of 47.4%. Bifidobacteria, Bacteroides, lactobacilli and clostridia were inhibited within the following ranges 47-78%, 32-65%, 11.7-58% and 64-85% respectively. This means that clostridia were the most strongly influenced members of the microflora amongst the bacterial groups tested in mixed culture. In conclusion, introducing oligosaccharides which are candidate prebiotics into pure or mixed cultures has affected bacterial adhesion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nitric oxide-releasing antibacterial albumin plastic for biomedical applications.

PubMed

Jones, Alexander; Pant, Jitendra; Lee, Eliza; Goudie, Marcus J; Gruzd, Alexey; Mansfield, Joel; Mandal, Abhyuday; Sharma, Suraj; Handa, Hitesh

2018-06-01

Designing innovative materials for biomedical applications is desired to prevent surface fouling and risk of associated infections arising in the surgical care patient. In the present study, albumin plastic was fabricated and nitric oxide (NO) donor, S-nitroso-N-acetylpenicillamine (SNAP), was incorporated through a solvent swelling process. The albumin-SNAP plastic was evaluated in terms of mechanical and thermal properties, and bacterial adhesion to the plastic surface. Thermal and viscoelastic analyses showed no significant difference between albumin-SNAP plastics and pure, water-plasticized albumin samples. Bacteria adhesion tests revealed that albumin-SNAP plastic can significantly reduce the surface-bound viable gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa bacterial cells by 98.7 and 98.5%, respectively, when compared with the traditional polyvinyl chloride medical grade tubing material. The results from this study demonstrate NO-releasing albumin plastic's potential as a material for biomedical device applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1535-1542, 2018. © 2018 Wiley Periodicals, Inc.

Microbial Adhesion and Biofilm Formation on Microfiltration Membranes: A Detailed Characterization Using Model Organisms with Increasing Complexity

PubMed Central

Vanysacker, L.; Denis, C.; Declerck, P.; Piasecka, A.; Vankelecom, I. F. J.

2013-01-01

Since many years, membrane biofouling has been described as the Achilles heel of membrane fouling. In the present study, an ecological assay was performed using model systems with increasing complexity: a monospecies assay using Pseudomonas aeruginosa or Escherichia coli separately, a duospecies assay using both microorganisms, and a multispecies assay using activated sludge with or without spiked P. aeruginosa. The microbial adhesion and biofilm formation were evaluated in terms of bacterial cell densities, species richness, and bacterial community composition on polyvinyldifluoride, polyethylene, and polysulfone membranes. The data show that biofouling formation was strongly influenced by the kind of microorganism, the interactions between the organisms, and the changes in environmental conditions whereas the membrane effect was less important. The findings obtained in this study suggest that more knowledge in species composition and microbial interactions is needed in order to understand the complex biofouling process. This is the first report describing the microbial interactions with a membrane during the biofouling development. PMID:23986906

Continuous monitoring of bacterial attachment

NASA Technical Reports Server (NTRS)

Koeing, D. W.; Mishra, S. K.; Pierson, D. L.

1994-01-01

A major concern with the Space Station Freedom (SSF) water supply system is the control of longterm microbial contamination and biofilm development in the water storage and distribution systems. These biofilms have the potential for harboring pathogens as well as microbial strains containing resistance factors that could negatively influence crew health. The proposed means for disinfecting the water system on SSF (iodine) may encourage the selection of resistant strains. In fact, biofilm bacteria were observed in water lines from the Space Shuttle Columbia (OV-102); therefore, an alternative remediation method is required to disinfect spacecraft water lines. A thorough understanding of colonization events and the physiological parameters that will influence bacteria adhesion is required. The limiting factor for development of this technology is the ability to continuously monitor adhesion events and the effects of biocides on sessile bacteria. Methods were developed to allow bacterial adhesion and subsequent biocidal treatment to be monitored continuously. This technique couples automated image analysis with a continuous flow of a bacterial suspension through an optical flow cell. A strain of Pseudomonas cepacia isolated from the water supply of the Space Shuttle Discovery (OV-103) during STS-39 was grown in a nitrogen-limited continuous culture. This culture was challenged continuously with iodine during growth, and the adhesion characteristics of this strain was measure with regard to flow rate. Various biocides (ozone, hypochlorite, and iodine) were added to the flow stream to evaluate how well each chemical removed the bacteria. After biocide treatment, a fresh bacterial suspension was introduced into the flow cell, and the attachment rate was evaluated on the previously treated surface. This secondary fouling was again treated with biocide to determine the efficacy of multiple batch chemical treatments in removing biofilm.

ATR-FTIR Spectroscopic Evidence for Biomolecular Phosphorus and Carboxyl Groups Facilitating Bacterial Adhesion to Iron Oxides

PubMed Central

Parikh, Sanjai J.; Mukome, Fungai N.D.; Zhang, Xiaoming

2014-01-01

Attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy has been used to probe the binding of bacteria to hematite (α-Fe2O3) and goethite (α-FeOOH). In situ ATR-FTIR experiments with bacteria (Pseudomonas putida, P. aeruginosa, Escherichia coli), mixed amino acids, polypeptide extracts, deoxyribonucleic acid (DNA), and a suite of model compounds were conducted. These compounds represent carboxyl, catecholate, amide, and phosphate groups present in siderophores, amino acids, polysaccharides, phospholipids, and DNA. Due in part to the ubiquitous presence of carboxyl groups in biomolecules, numerous IR peaks corresponding to outer-sphere or unbound (1400 cm−1) and inner-sphere (1310-1320 cm−1) coordinated carboxyl groups are noted following reaction of bacteria and biomolecules with α-Fe2O3 and α-FeOOH. However, the data also reveal that the presence of low-level amounts (i.e., 0.45-0.79%) of biomolecular phosphorous groups result in strong IR bands at ~1043 cm−1, corresponding to inner-sphere Fe-O-P bonds, underscoring the importance of bacteria associated P-containing groups in biomolecule and cell adhesion. Spectral comparisons also reveal slightly greater P-O-Fe contributions for bacteria (Pseudomonad, E. coli) deposited on α-FeOOH, as compared to α-Fe2O3. This data demonstrates that slight differences in bacterial adhesion to Fe oxides can be attributed to bacterial species and Fe-oxide minerals. However, more importantly, the strong binding affinity of phosphate in all bacteria samples to both Fe-oxides results in the formation of inner-sphere Fe-O-P bonds, signifying the critical role of biomolecular P in the initiation of bacterial adhesion. PMID:24859052

Innate immunity glycoprotein gp-340 variants may modulate human susceptibility to dental caries

PubMed Central

Jonasson, Anette; Eriksson, Christer; Jenkinson, Howard F; Källestål, Carina; Johansson, Ingegerd; Strömberg, Nicklas

2007-01-01

Background Bacterial adhesion is an important determinant of colonization and infection, including dental caries. The salivary scavenger receptor cysteine-rich glycoprotein gp-340, which mediates adhesion of Streptococcus mutans (implicated in caries), harbours three major size variants, designated gp-340 I to III, each specific to an individual saliva. Here we have examined the association of the gp-340 I to III polymorphisms with caries experience and adhesion of S. mutans. Methods A case-referent study was performed in 12-year-old Swedish children with high (n = 19) or low (n = 19) caries experiences. We measured the gp-340 I to III saliva phenotypes and correlated those with multiple outcome measures for caries experience and saliva adhesion of S. mutans using the partial least squares (PLS) multivariate projection technique. In addition, we used traditional statistics and 2-year caries increment to verify the established PLS associations, and bacterial adhesion to purified gp-340 I to III proteins to support possible mechanisms. Results All except one subject were typed as gp-340 I to III (10, 23 and 4, respectively). The gp-340 I phenotype correlated positively with caries experience (VIP = 1.37) and saliva adhesion of S. mutans Ingbritt (VIP = 1.47). The gp-340 II and III phenotypes tended to behave in the opposite way. Moreover, the gp-340 I phenotype tended to show an increased 2-year caries increment compared to phenotypes II/III. Purified gp-340 I protein mediated markedly higher adhesion of S. mutans strains Ingbritt and NG8 and Lactococcus lactis expressing AgI/II adhesins (SpaP or PAc) compared to gp-340 II and III proteins. In addition, the gp-340 I protein appeared over represented in subjects positive for Db, an allelic acidic PRP variant associated with caries, and subjects positive for both gp-340 I and Db tended to experience more caries than those negative for both proteins. Conclusion Gp-340 I behaves as a caries susceptibility protein. PMID:17562017

Genome shuffling of Lactobacillus plantarum C88 improves adhesion.

PubMed

Zhao, Yujuan; Duan, Cuicui; Gao, Lei; Yu, Xue; Niu, Chunhua; Li, Shengyu

2017-01-01

Genome shuffling is an important method for rapid improvement in microbial strains for desired phenotypes. In this study, ultraviolet irradiation and nitrosoguanidine were used as mutagens to enhance the adhesion of the wild-type Lactobacillus plantarum C88. Four strains with better property were screened after mutagenesis to develop a library of parent strains for three rounds of genome shuffling. Fusants F3-1, F3-2, F3-3, and F3-4 were screened as the improved strains. The in vivo and in vitro tests results indicated that the population after three rounds of genome shuffling exhibited improved adhesive property. Random Amplified Polymorphic DNA results showed significant differences between the parent strain and recombinant strains at DNA level. These results suggest that the adhesive property of L. plantarum C88 can be significantly improved by genome shuffling. Improvement in the adhesive property of bacterial cells by genome shuffling enhances the colonization of probiotic strains which further benefits to exist probiotic function.

Biodiversity of mannose-specific adhesion in Lactobacillus plantarum revisited: strain-specific domain composition of the mannose-adhesin.

PubMed

Gross, G; Snel, J; Boekhorst, J; Smits, M A; Kleerebezem, M

2010-03-01

Recently, we have identified the mannose-specific adhesin encoding gene (msa) of Lactobacillus plantarum. In the current study, structure and function of this potentially probiotic effector gene were further investigated, exploring genetic diversity of msa in L. plantarum in relation to mannose adhesion capacity. The results demonstrate that there is considerable variation in quantitative in vitro mannose adhesion capacity, which is paralleled by msa gene sequence variation. The msa genes of different L. plantarum strains encode proteins with variable domain composition. Construction of L. plantarum 299v mutant strains revealed that the msa gene product is the key-protein for mannose adhesion, also in a strain with high mannose adhering capacity. However, no straightforward correlation between adhesion capacity and domain composition of Msa in L. plantarum could be identified. Nevertheless, differences in Msa sequences in combination with variable genetic background of specific bacterial strains appears to determine mannose adhesion capacity and potentially affects probiotic properties. These findings exemplify the strain-specificity of probiotic characteristics and illustrate the need for careful and molecular selection of new candidate probiotics.

Identification and adhesion profile of Lactobacillus spp. strains isolated from poultry

PubMed Central

Rocha, Ticiana Silva; Baptista, Ana Angelita Sampaio; Donato, Tais Cremasco; Milbradt, Elisane Lenita; Okamoto, Adriano Sakai; Filho, Raphael Lucio Andreatti

2014-01-01

In the aviculture industry, the use of Lactobacillus spp. as a probiotic has been shown to be frequent and satisfactory, both in improving bird production indexes and in protecting intestine against colonization by pathogenic bacteria. Adhesion is an important characteristic in selecting Lactobacillus probiotic strains since it impedes its immediate elimination to enable its beneficial action in the host. This study aimed to isolate, identify and characterize the in vitro and in vivo adhesion of Lactobacillus strains isolated from birds. The Lactobacillus spp. was identified by PCR and sequencing and the strains and its adhesion evaluated in vitro via BMM cell matrix and in vivo by inoculation in one-day-old birds. Duodenum, jejunum, ileum and cecum were collected one, four, 12 and 24 h after inoculation. The findings demonstrate greater adhesion of strains in the cecum and an important correlation between in vitro and in vivo results. It was concluded that BMM utilization represents an important technique for triage of Lactobacillus for subsequent in vivo evaluation, which was shown to be efficient in identifying bacterial adhesion to the enteric tract. PMID:25477944

The surface protease ompT serves as Escherichia coli K1 adhesin in binding to human brain micro vascular endothelial cells.

PubMed

Wan, Lei; Guo, Yan; Hui, Chang-Ye; Liu, Xiao-Lu; Zhang, Wen-Bing; Cao, Hong; Cao, Hong

2014-05-01

Escherichia coli (E. coli) K1 is the most common bacteria that cause meningitis in the neonatal period. But it's not entirely clear about how E. coli crosses the blood-brain barrier. The features of the ompT deletion in meningitic E. coli infection were texted in vitro. In comparison with the parent strain, the isogenic ompT deletion mutant was significantly less adhesive to human brain microvascular endothelial cells (HBMEC). The adhesion-deficient phenotype of the mutant was restored to the level of the wild-type by complementing with low-level OmpT expression plasmid. Interestingly, the adhesion was enhanced by point mutation at the OmpT proposed catalytic residue D85. Compared with the poor adhesive activity of bovine serum albumin-coated fluorescent beads, recombinant OmpT or catalytically inactive variant of OmpT-coated beads bound to HBMEC monolayer effectively. Our study suggests that OmpT is important for bacterial adhesion while entering into central nervous system, and the adhesion does not involve in the proteolytic activity of OmpT.

Atomic Force Microscope Investigations of Bacterial Biofilms Treated with Gas Discharge Plasmas

NASA Astrophysics Data System (ADS)

Vandervoort, Kurt; Zelaya, Anna; Brelles-Marino, Graciela

2012-02-01

We present investigations of bacterial biofilms before and after treatment with gas discharge plasmas. Gas discharge plasmas represent a way to inactivate bacteria under conditions where conventional disinfection methods are often ineffective. These conditions involve biofilm communities, where bacteria grow embedded in an exopolysaccharide matrix, and cooperative interactions between cells make organisms less susceptible to standard inactivation methods. In this study, biofilms formed by the opportunistic bacterium Pseudomonas aeruginosa were imaged before and after plasma treatment using an atomic force microscope (AFM). Through AFM images and micromechanical measurements we observed bacterial morphological damage and reduced AFM tip-sample surface adhesion following plasma treatment.

Solvent-free functionalization of silicone rubber and efficacy of PAAm brushes grafted from an amino-PPX layer against bacterial adhesion.

PubMed

Fundeanu, Irina; Klee, Doris; Schouten, Arend J; Busscher, Henk J; van der Mei, Henny C

2010-11-01

Silicone rubber is a frequently employed biomaterial that is prone to bacterial adhesion and biofilm formation. In this study, the surface of silicone rubber was solvent-free functionalized by chemical vapor deposition (CVD) of poly(o-amino-p-xylylene-co-p-xylylene (amino-PPX). Subsequently, the amino groups of the amino-PPX layer were used to introduce the initiator from a vapor phase for atom transfer radical polymerization of acrylamide to form polyacrylamide (PAAm) brushes. The modification steps were verified by means of X-ray photoelectron spectroscopy and attenuated total reflection-Fourier transform infrared spectroscopy. Adhesion of Staphylococcus aureus ATCC 12600 and Escherichia coli 3.14 to an amino-PPX-PAAm brush coating in a parallel plate flow chamber was strongly reduced with respect to non-coated silicone rubber - by 93% and 99%, respectively. For E. coli 3.14, this reduction is larger than that obtained for solvent functionalization of γ-aminopropyltriethoxysilane-PAAm brushes due to the higher density of amino groups introduced by the CVD of amino-PPX. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Competitive time- and density-dependent adhesion of staphylococci and osteoblasts on crosslinked poly(ethylene glycol)-based polymer coatings in co-culture flow chambers.

PubMed

Saldarriaga Fernández, Isabel C; Busscher, Henk J; Metzger, Steve W; Grainger, David W; van der Mei, Henny C

2011-02-01

Biomaterial-associated infections (BAI) remain a serious clinical complication, often arising from an inability of host tissue-implant integration to out-compete bacterial adhesion and growth. A commercial polymer coating based on polyethylene glycol (PEG), available in both chemically inert and NHS-activated forms (OptiChem(®)), was compared for simultaneous growth of staphylococci and osteoblasts. In the absence of staphylococci, osteoblasts adhered and proliferated well on glass controls and on the NHS-reactive PEG-based coating over 48 h, but not on the inert PEG coating. Staphylococcal growth was low on both PEG-based coatings. When staphylococci were pre-adhered on surfaces for 1.5 h to mimic peri-operative contamination, osteoblast growth and spreading was reduced on glass but virtually absent on both reactive and inert PEG-based coatings. Thus although NHS-reactive, PEG-based coatings stimulated tissue-cell interactions in the absence of contaminating staphylococci, the presence of adhering staphylococci eliminated osteoblast adhesion advantages on the PEG surface. This study demonstrates the importance of using bacterial and cellular co-cultures compared to monocultures when assessing functionalized biomaterials coatings for infectious potential. Copyright © 2010 Elsevier Ltd. All rights reserved.

Pilicides inhibit the FGL chaperone/usher assisted biogenesis of the Dr fimbrial polyadhesin from uropathogenic Escherichia coli

PubMed Central

2013-01-01

Background The global spread of bacterial resistance has given rise to a growing interest in new anti-bacterial agents with a new strategy of action. Pilicides are derivatives of ring-fused 2-pyridones which block the formation of the pili/fimbriae crucial to bacterial pathogenesis. They impair by means of a chaperone-usher pathway conserved in the Gram-negative bacteria of adhesive structures biogenesis. Pili/fimbriae of this type belong to two subfamilies, FGS and FGL, which differ in the details of their assembly mechanism. The data published to date have shown that pilicides inhibit biogenesis of type 1 and P pili of the FGS type which are encoded by uropathogenic E. coli strains. Results We evaluated the anti-bacterial activity of literature pilicides as blockers of the assembly of a model example of FGL-type adhesive structures, – the Dr fimbriae encoded by a dra gene cluster of uropathogenic Escherichia coli strains. In comparison to the strain grown without pilicide, the Dr+ bacteria cultivated in the presence of the 3.5 mM concentration of pilicides resulted in a reduction of 75 to 87% in the adherence properties to CHO cells expressing Dr fimbrial DAF receptor protein. Using quantitative assays, we determined the amount of Dr fimbriae in the bacteria cultivated in the presence of 3.5 mM of pilicides to be reduced by 75 to 81%. The inhibition effect of pilicides is concentration dependent, which is a crucial property for their use as potential anti-bacterial agents. The data presented in this article indicate that pilicides in mM concentration effectively inhibit the adherence of Dr+ bacteria to the host cells, – the crucial, initial step in bacterial pathogenesis. Conclusions Structural analysis of the DraB chaperone clearly showed it to be a model of the FGL subfamily of chaperones. This permits us to conclude that analyzed pilicides in mM concentration are effective inhibitors of the assembly of adhesins belonging to the Dr family, and more speculatively, of other FGL-type adhesive organelles. The presented data and those published so far permit to speculate that based on the conservation of chaperone-usher pathway in Gram-negative bacteria , the pilicides are potential anti-bacterial agents with activity against numerous pathogens, the virulence of which is dependent on the adhesive structures of the chaperone-usher type. PMID:23758700

Discriminatory bio-adhesion over nano-patterned polymer brushes

NASA Astrophysics Data System (ADS)

Gon, Saugata

Surfaces functionalized with bio-molecular targeting agents are conventionally used for highly-specific protein and cell adhesion. This thesis explores an alternative approach: Small non-biological adhesive elements are placed on a surface randomly, with the rest of the surface rendered repulsive towards biomolecules and cells. While the adhesive elements themselves, for instance in solution, typically exhibit no selectivity for various compounds within an analyte suspension, selective adhesion of targeted objects or molecules results from their placement on the repulsive surface. The mechanism of selectivity relies on recognition of length scales of the surface distribution of adhesive elements relative to species in the analyte solution, along with the competition between attractions and repulsions between various species in the suspension and different parts of the collecting surface. The resulting binding selectivity can be exquisitely sharp; however, complex mixtures generally require the use of multiple surfaces to isolate the various species: Different components will be adhered, sharply, with changes in collector composition. The key feature of these surface designs is their lack of reliance on biomolecular fragments for specificity, focusing entirely on physicochemical principles at the lengthscales from 1 - 100 nm. This, along with a lack of formal patterning, provides the advantages of simplicity and cost effectiveness. This PhD thesis demonstrates these principles using a system in which cationic poly-L-lysine (PLL) patches (10 nm) are deposited randomly on a silica substrate and the remaining surface is passivated with a bio-compatible PEG brush. TIRF microscopy revealed that the patches were randomly arranged, not clustered. By precisely controlling the number of patches per unit area, the interfaces provide sharp selectivity for adhesion of proteins and bacterial cells. For instance, it was found that a critical density of patches (on the order of 1000/mum 2) was required for fibrinogen adsorption while a greater density comprised the adhesion threshold for albumin. Surface compositions between these two thresholds discriminated binding of the two proteins. The binding behavior of the two proteins from a mixture was well anticipated by the single- protein binding behaviors of the individual proteins. The mechanism for protein capture was shown to be multivalent: protein adhesion always occurred for averages spacings of the adhesive patches smaller than the dimensions of the protein of interest. For some backfill brush architectures, the spacing between the patches at the threshold for protein capture clearly corresponded to the major dimension of the target protein. For more dense PEG brush backfills however, larger adhesion thresholds were observed, corresponding to greater numbers of patches involved with the adhesion of each protein molecule. . The thesis demonstrates the tuning of the position of the adhesion thresholds, using fibrinogen as a model protein, using variations in brush properties and ionic strength. The directions of the trends indicate that the brushes do indeed exert steric repulsions toward the proteins while the attractions are electrostatic in nature. The surfaces also demonstrated sharp adhesion thresholds for S. Aureus bacteria, at smaller concentrations of adhesive surfaces elements than those needed for the protein capture. The results suggest that bacteria may be captured while proteins are rejected from these surfaces, and there may be potential to discriminate different bacterial types. Such discrimination from protein-containing bacterial suspensions was investigated briefly in this thesis using S. Aureus and fibrinogen as a model mixture. However, due to binding of fibrinogen to the bacterial surface, the separation did not succeed. It is still expected, however, that these surfaces could be used to selectively capture bacteria in the presence of non-interacting proteins. The interaction of these brushes with two different cationic species PLL and lysozyme were studied. The thesis documents rapid and complete brush displacement by PLL, highlighting a major limitation of using such brushes in some applications. Also unanticipated, lysozyme, a small cationic protein, was found to adhere to the brushes in increasing amounts with the PEG content of the brush. This finding contradicts current understanding of protein-brush interactions that suggests increases in interfacial PEG content increase biocompatibility.

Silver-nanoparticle-coated biliary stent inhibits bacterial adhesion in bacterial cholangitis in swine.

PubMed

Wen, Wei; Ma, Li-Mei; He, Wei; Tang, Xiao-Wei; Zhang, Yin; Wang, Xiang; Liu, Li; Fan, Zhi-Ning

2016-02-01

One of the major limitations of biliary stents is the stent occlusion, which is closely related to the over-growth of bacteria. This study aimed to evaluate the feasibility of a novel silver-nanoparticle-coated polyurethane (Ag/PU) stent in bacterial cholangitis model in swine. Ag/PU was designed by coating silver nanoparticles on polyurethane (PU) stent. Twenty-four healthy pigs with bacterial cholangitis using Ag/PU and PU stents were randomly divided into an Ag/PU stent group (n=12) and a PU stent group (n=12), respectively. The stents were inserted by standard endoscopic retrograde cholangiopancreatography. Laboratory assay was performed for white blood cell (WBC) count, alanine aminotransferase (ALT), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha) at baseline time, 8 hours, 1, 2, 3, and 7 days after stent placements. The segment of bile duct containing the stent was examined histologically ex vivo. Implanted biliary stents were examined by a scan electron microscope. The amount of silver release was also measured in vitro. The number of inflammatory cells and level of ALT, IL-1beta and TNF-alpha were significantly lower in the Ag/PU stent group than in the PU stent group. Hyperplasia of the mucosa was more severe in the PU stent group than in the Ag/PU stent group. In contrast to the biofilm of bacteria on the PU stent, fewer bacteria adhered to the Ag/PU stent. PU biliary stents modified with silver nanoparticles are able to alleviate the inflammation of pigs with bacterial cholangitis. Silver-nanoparticle-coated stents are resistant to bacterial adhesion.

The Highly Autoaggregative and Adhesive Phenotype of the Vaginal Lactobacillus plantarum Strain CMPG5300 Is Sortase Dependent

PubMed Central

Malik, Shweta; Petrova, Mariya I.; Claes, Ingmar J. J.; Verhoeven, Tine L. A.; Busschaert, Pieter; Vaneechoutte, Mario; Lievens, Bart; Lambrichts, Ivo; Siezen, Roland J.; Balzarini, Jan; Vanderleyden, Jos

2013-01-01

Lactobacilli are important for the maintenance of a healthy ecosystem in the human vagina. Various mechanisms are postulated but so far are poorly substantiated by molecular studies, such as mutant analysis. Bacterial autoaggregation is an interesting phenomenon that can promote adhesion to host cells and displacement of pathogens. In this study, we report on the identification of a human vaginal isolate, Lactobacillus plantarum strain CMPG5300, which shows high autoaggregative and adhesive capacity. To investigate the importance of sortase-dependent proteins (SDPs) in these phenotypes, a gene deletion mutant was constructed for srtA, the gene encoding the housekeeping sortase that covalently anchors these SDPs to the cell surface. This mutant lost the capacity to autoaggregate, showed a decrease in adhesion to vaginal epithelial cells, and lost biofilm-forming capacity under the conditions tested. These results indicate that the housekeeping sortase SrtA of CMPG5300 is a key determinant of the peculiar surface properties of this vaginal Lactobacillus strain. PMID:23709503

Influence of Surface Properties on the Adhesion of Staphylococcus epidermidis to Acrylic and Silicone

PubMed Central

Sousa, Cláudia; Teixeira, Pilar; Oliveira, Rosário

2009-01-01

The aim of the present study was to compare the ability of eight Staphylococcus epidermidis strains to adhere to acrylic and silicone, two polymers normally used in medical devices manufacture. Furthermore, it was tried to correlate that with the surface properties of substrata and cells. Therefore, hydrophobicity and surface tension components were calculated through contact angle measurements. Surface roughness of substrata was also assessed by atomic force microscopy (AFM). No relationship was found between microbial surface hydrophobicity and adhesion capability. Nevertheless, Staphylococcus epidermidis IE214 showed very unique adhesion behaviour, with cells highly aggregated between them, which is a consequence of their specific surface features. All strains, determined as being hydrophilic, adhered at a higher extent to silicone than to acrylic, most likely due to its more hydrophobic character and higher roughness. This demonstrates the importance of biomaterial surface characteristics for bacterial adhesion. PMID:20126579

Histological evaluation of direct pulp capping with all-in-one adhesives in rat teeth.

PubMed

Shinkai, Koichi; Taira, Yoshihisa; Kawashima, Satoki; Suzuki, Shiro; Suzuki, Masaya

2017-05-31

The aim of this study was to histologically evaluate direct pulp capping using different all-in-one adhesives in rat teeth. Five all-in-one adhesives and a control material (MTA) were used. Each material was applied on the exposed pulp, and each cavity was subsequently restored with the resin composite. Rats were sacrificed 14 days after the surgical procedure. Serial stained sections were histologically evaluated for examining pulp tissue disorganization (PTD), inflammatory cell infiltration (ICI), dentin bridge formation (DBF), and bacterial penetration (BP). We found that rat pulps, which were direct capped with all-in-one adhesives, showed various degrees of PTD, ICI, and DBF depending on the material, and that there were no complete dentin bridges. In contrast, rat pulps capped with MTA showed no PTD and ICI, and there were complete dentin bridges in all, but one specimen. No BP was observed in any specimen.

Agglutination of Mouse Erythrocytes by Eperythrozoon coccoides

PubMed Central

Iralu, Vichazelhu; Ganong, Kevin D.

1983-01-01

Erythrocytes from blood of mice infected with Eperythrozoon coccoides for 3 or 4 days agglutinated spontaneously. Washed E. coccoides particles agglutinated washed erythrocytes of uninfected mice. E. coccoides-mediated agglutination of normal mouse erythrocytes would be an excellent system for studies of bacterial adhesion. Images PMID:6832825

Adhesion of Streptococcus sanguis CH3 to polymers with different surface free energies.

PubMed Central

van Pelt, A W; Weerkamp, A H; Uyen, M H; Busscher, H J; de Jong, H P; Arends, J

1985-01-01

The adhesion of the oral bacterium Streptococcus sanguis CH3 to various polymeric surfaces with surface free energies (gamma s) ranging from 22 to 141 erg cm-2 was investigated. Suspensions containing nine different bacterial concentrations (2.5 X 10(7) to 2.5 X 10(9) cells per ml) were used. After adhesion for 1 h at 21 degrees C and a standardized rinsing procedure, the number of attached bacteria per square centimeter (nb) was determined by scanning electron microscopy. The highest number of bacteria was consistently found on polytetrafluorethylene (gamma s = 22 erg cm-2), and the lowest number was found on glass (gamma s = 141 erg cm-2) at all bacterial concentrations tested. The overall negative correlation between nb and gamma s was weak. However, the slope of the line showing this decrease, calculated from an assumed linear relationship between nb and gamma s, appeared to depend strongly on the bacterial concentration and increased with increasing numbers of bacteria in the suspension. Analysis of the data for each separate polymer showed that the numbers of attached cells on polyvinyl chloride and polypropylene were higher but that those on polycarbonate were lower than would be expected on basis of a linear relationship between nb and gamma s. Desorption experiments were performed by first allowing the bacteria to attach to substrata for 1 h, after which the substrata and attached bacteria were removed to bacterial suspensions containing 10-fold lower bacterial concentrations.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:4004241

A force sensor using nanowire arrays to understand biofilm formation (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sahoo, Prasana K.; Cavalli, Alessandro; Pelegati, Vitor B.; Murillo, Duber M.; Souza, Alessandra A.; Cesar, Carlos L.; Bakkers, Erik P. A. M.; Cotta, Monica A.

2016-03-01

Understanding the cellular signaling and function at the nano-bio interface can pave the way towards developing next-generation smart diagnostic tools. From this perspective, limited reports detail so far the cellular and subcellular forces exerted by bacterial cells during the interaction with abiotic materials. Nanowire arrays with high aspect ratio have been used to detect such small forces. In this regard, live force measurements were performed ex-vivo during the interaction of Xylella fastidiosa bacterial cells with InP nanowire arrays. The influence of nanowire array topography and surface chemistry on the response and motion of bacterial cells was studied in detail. The nanowire arrays were also functionalized with different cell adhesive promoters, such as amines and XadA1, an afimbrial protein of X.fastidiosa. By employing the well-defined InP nanowire arrays platform, and single cell confocal imaging system, we were able to trace the bacterial growth pattern, and show that their initial attachment locations are strongly influenced by the surface chemistry and nanoscale surface topography. In addition, we measure the cellular forces down to few nanonewton range using these nanowire arrays. In case of nanowire functionalized with XadA1, the force exerted by vertically and horizontally attached single bacteria on the nanowire is in average 14% and 26% higher than for the pristine array, respectively. These results provide an excellent basis for live-cell force measurements as well as unravel the range of forces involved during the early stages of bacterial adhesion and biofilm formation.

Immunological reactions to Salmonella FlgK and FliD flagellar proteins by broiler sera

USDA-ARS?s Scientific Manuscript database

Background: Salmonella is the leading foodborne pathogen that causes human acute bacterial gastroenteritis worldwide. Chickens are considered as one of major reservoirs of this bacterium. Because the bacterial flagellum is involved in motility, adhesion, quorum sensing and other virulence activit...

Reactions of broiler sera to salmonella FlgK and FliD flagellar proteins

USDA-ARS?s Scientific Manuscript database

Introduction: Salmonella, a Gram-negative bacterium, is the leading foodborne pathogen. It causes human acute bacterial gastroenteritis worldwide. Poultry products are considered as one of major reservoirs of this bacterium. Because the bacterial flagellum is involved in motility, adhesion and o...

Cranberry juice-- a well-characterized folk-remedy against bacterial urinary tract infection.

PubMed

Nowack, Rainer

2007-01-01

Cranberry (Vaccinium macrocarpon) is a North-American folk remedy for treating and preventing infection. Research has identified an anti-adhesive mechanism of cranberry-proanthocyanidins that inhibit docking of bacteria on tissues "in vitro". This efficacy mechanism can be traced in the patient's urine following oral intake of cranberry juice. The efficacy of cranberry juice and extracts as a prophylactic agent against recurrent urinary infections is well documented in women. The anti-adhesion effect of cranberry-proanthocyandins can also be applied for treatment of other common diseases of bacterial pathogenesis, e.g. Helicobacter pylori-associated gastritis and dental caries/periodontal disease.

The design of superhydrophobic stainless steel surfaces by controlling nanostructures: A key parameter to reduce the implantation of pathogenic bacteria.

PubMed

Bruzaud, Jérôme; Tarrade, Jeanne; Celia, Elena; Darmanin, Thierry; Taffin de Givenchy, Elisabeth; Guittard, Frédéric; Herry, Jean-Marie; Guilbaud, Morgan; Bellon-Fontaine, Marie-Noëlle

2017-04-01

Reducing bacterial adhesion on substrates is fundamental for various industries. In this work, new superhydrophobic surfaces are created by electrodeposition of hydrophobic polymers (PEDOT-F 4 or PEDOT-H 8 ) on stainless steel with controlled topographical features, especially at a nano-scale. Results show that anti-bioadhesive and anti-biofilm properties require the control of the surface topographical features, and should be associated with a low adhesion of water onto the surface (Cassie-Baxter state) with limited crevice features at the scale of bacterial cells (nano-scale structures). Copyright © 2016. Published by Elsevier B.V.

Effect of Dietary Minerals on Virulence Attributes of Vibrio cholerae

PubMed Central

Bhattaram, Varunkumar; Upadhyay, Abhinav; Yin, Hsin-Bai; Mooyottu, Shankumar; Venkitanarayanan, Kumar

2017-01-01

Vibrio cholerae is a water-borne pathogen responsible for causing a toxin-mediated profuse diarrhea in humans, leading to severe dehydration and death in unattended patients. With increasing reports of antibiotic resistance in V. cholerae, there is a need for alternate interventional strategies for controlling cholera. A potential new strategy for treating infectious diseases involves targeting bacterial virulence rather than growth, where a pathogen’s specific mechanisms critical for causing infection in hosts are inhibited. Since bacterial motility, intestinal colonization and cholera toxin are critical components in V. cholerae pathogenesis, attenuating these virulence factors could potentially control cholera in humans. In this study, the efficacy of sub-inhibitory concentration (SIC, highest concentration not inhibiting bacterial growth) of essential minerals, zinc (Zn), selenium (Se), and manganese (Mn) in reducing V. cholerae motility and adhesion to intestinal epithelial cells (Caco-2), cholera toxin production, and toxin binding to the ganglioside receptor (GM1) was investigated. Additionally, V. cholerae attachment and toxin production in an ex vivo mouse intestine model was determined. Further, the effect of Zn, Se and Mn on V. cholerae virulence genes, ctxAB (toxin production), fliA (motility), tcpA (intestinal colonization), and toxR (master regulon) was determined using real-time quantitative PCR. All three minerals significantly reduced V. cholerae motility, adhesion to Caco-2 cells, and cholera toxin production in vitro, and decreased adhesion and toxin production in mouse intestine ex vivo (P < 0.05). In addition, Zn, Se, and Mn down-regulated the transcription of virulence genes, ctxAB, fliA, and toxR. Results suggest that Zn, Se, and Mn could be potentially used to reduce V. cholerae virulence. However, in vivo studies in an animal model are necessary to validate these results. PMID:28579983

Salmonella enterica Serovar Kentucky Flagella are Required for Broiler Skin Adhesion and Caco-2 Cell Invasion

USDA-ARS?s Scientific Manuscript database

Non-typhoidal Salmonella are the main source of pathogenic bacterial contamination in the poultry industry. Recently, Salmonella enterica serovar Kentucky has been recognized as the most prominent serovar on carcasses in poultry processing plants. Previous studies showed that flagella are one of the...

Salmonella enterica serovar Kentucky flagella are required for broiler skin adhesion and Caco-2 cell invasion

USDA-ARS?s Scientific Manuscript database

Nontyphoidal Salmonella strains are the main source of pathogenic bacterial contamination in the poultry industry. Recently, Salmonella enterica serovar Kentucky has been recognized as the most prominent serovar on carcasses in poultry-processing plants. Previous studies showed that flagella are one...

A novel high-throughput assay to quantify the vaccine-induced inhibition of Bordetella pertussis adhesion to airway epithelia.

PubMed

Zanaboni, Elisa; Arato, Vanessa; Pizza, Mariagrazia; Seubert, Anja; Leuzzi, Rosanna

2016-09-15

Pertussis or whooping cough is an acute respiratory illness caused by the Gram-negative pathogen Bordetella pertussis. Despite high vaccination coverage whooping cough is currently re-emerging in many developed countries. Although the causes of pertussis resurgence are matter of debate, emerging evidences suggest that acellular vaccines efficiently protect against the hallmark symptoms of pertussis disease but fail to prevent colonization. This presumably impacts on increased risk of bacterial transmission and consequent spread throughout the population. These evidences suggest that improved vaccines may be required for efficient bacterial clearance in the upper respiratory tract. Consequently, there is a need for novel bioassays to evaluate at pre-clinical or clinical level the impact of different vaccines on B. pertussis colonization. We developed a high-throughput bacterial adhesion inhibition (BAI) assay based on human respiratory cell lines and on live bacteria chemically conjugated to a fluorescent dye. Employing A549 cells as model, we evaluated the impact of antibodies elicited by acellular (aP) and whole cell (wP) vaccines on B. pertussis adhesion in vitro. Moreover, we settled the method also on polarized Calu-3 cells grown at air-liquid interface (ALI), showing that this assay can be extended to more complex cell models mimicking the airway epithelium. We proved that this method is a sensitive, rapid and reproducible system to evaluate the anti-adhesive properties of vaccine-induced antibodies and can be employed to assess improved pertussis vaccines.

Electrochemical determination of the onset of bacterial surface adhesion

NASA Astrophysics Data System (ADS)

Jones, Akhenaton-Andrew; Buie, Cullen

2017-11-01

Microbial biofouling causes economic loss through corrosion and drag losses on ship hulls, and in oil and food distribution. Microorganisms interacting with surfaces under these open channel flows contend with high shear rates and active transport to the surface. The metallic surfaces they interact with carry charge at various potentials that are little addressed in literature. In this study we demonstrate that the Levich curve, chronoamperometry, and cyclic voltammetry in a rotating disk electrode are ideal for studying adhesion of microbes to metallic surfaces. We study the adhesion of Escherichia coli, Bacillus subtilis, and 1 μm silica microspheres over a 0.15 - 37.33 dynes .cm-2 or shear rates of 14.73 - 3727.28 s-1 range. Our results agree with literature on red blood cells in rotating disk electrodes, deposition rates from optical systems, and show that we can quantify changes in active electrode area by bacteria adhesion and protein secretion. These methods measure changes in area instead of mass, are more accurate than fluorescence microscopy, and apply to a larger range of problems than on-chip flow devices.

pH and effects on Streptococcus mutans growth of denture adhesives: an in vitro study.

PubMed

Chen, Fengying; Mao, Tiantian; Cheng, Xiangrong

2014-06-01

To evaluate the pH and effects on Streptococcus mutans growth of denture adhesives. There is little information regarding the pH of contemporary adhesives and their influences on S. mutans growth. The adhesives tested were Polident® cream, Protefix® cream and Protefix® powder. Samples of each adhesive were added to deionized water to produce solutions of 10.0, 5.0, 2.5 and 1.0% w/v (cream formulations) or 5.0, 2.5,1.0 and 0.5% (powder formulation). The pH values were measured immediately after preparation and at 1-, 2-, 3-, 6-, 12-, and 24-h intervals using a digital pH meter. Streptococcus mutans UA159 was inoculated in the Brain Heart Infusion medium with or without the adhesive extracts (control). Bacterial growth was observed by measuring absorption at 600 nm every 1 h for 12 h using a spectrophotometer. The tested adhesives generally remained relatively pH-stable over 24 h, ranging from 5.5 to 7.0. There were no statistically significant differences in S. mutans growth rates between the extract-treated and control cultures (p>0.5). Some adhesives produce a pH below the critical pH of hydroxyapatite and may not be suitable for patients with natural teeth. None of the tested adhesives significantly affect S. mutans growth. © 2012 The Gerodontology Society and John Wiley & Sons A/S.

Solid residues from Ruminococcus cellulose fermentations as components of wood adhesive formulations

Treesearch

P.J. Weimer; A.H. Conner; L.F. Lorenz

2003-01-01

Residues from the fermentation of cellulose by the anaerobic bacteria Ruminococcus albus (strain 7) or Ruminococcus flavefaciens (strains FD-1 or B34b) containing residual cellulose, bacterial cells and their associated adhesins, were examined for their ability to serve as components of adhesives for plywood fabrication. The residues contained differing amounts of...

Direct observation of bacterial deposition onto clean and organic-fouled polyamide membranes.

PubMed

Subramani, Arun; Huang, Xiaofei; Hoek, Eric M V

2009-08-01

Nanofiltration (NF) and reverse osmosis (RO) membranes are commonly applied to produce highly purified water from municipal wastewater effluents. In these applications, biofouling limits overall process performance and increases the cost of operation. Initial bacteria adhesion onto a membrane surface is a critical early step in the overall process of membrane biofouling. However, adsorption of effluent organic matter onto the membrane may precede bacterial deposition and change membrane surface properties. Herein we employed direct microscopic observation to elucidate mechanisms governing bacterial cell deposition onto clean and organic-fouled NF and RO membranes. Bovine serum albumin (BSA) and alginic acid (AA) were used as models for protein and polysaccharide rich organic matter in secondary wastewater effluents. In all experiments, organic fouling increased membrane hydraulic resistance and salt rejection, in addition to interfacial hydrophilicity and roughness. Even though surface hydrophilicity increased, the rougher surfaces presented by organic-fouled membranes produced nano-scale features that promoted localized bacterial deposition. An extended DLVO analysis of bacterial cells and membrane surface properties suggested that bacterial deposition correlated most strongly with the Lewis acid-base free energy of adhesion and root mean square (RMS) roughness, whereas van der Waals and electrostatic free energies were weakly correlated. This was true for both clean and organic-fouled membranes. Bacterial deposition rates were clearly influenced by an antagonistic interplay between macroscopic surface hydrophilicity and nano-scale surface roughness.

Capsular Sialic Acid of Streptococcus suis Serotype 2 Binds to Swine Influenza Virus and Enhances Bacterial Interactions with Virus-Infected Tracheal Epithelial Cells

PubMed Central

Wang, Yingchao; Gagnon, Carl A.; Savard, Christian; Music, Nedzad; Srednik, Mariela; Segura, Mariela; Lachance, Claude; Bellehumeur, Christian

2013-01-01

Streptococcus suis serotype 2 is an important swine bacterial pathogen, and it is also an emerging zoonotic agent. It is unknown how S. suis virulent strains, which are usually found in low quantities in pig tonsils, manage to cross the first host defense lines to initiate systemic disease. Influenza virus produces a contagious infection in pigs which is frequently complicated by bacterial coinfections, leading to significant economic impacts. In this study, the effect of a preceding swine influenza H1N1 virus (swH1N1) infection of swine tracheal epithelial cells (NTPr) on the ability of S. suis serotype 2 to adhere to, invade, and activate these cells was evaluated. Cells preinfected with swH1N1 showed bacterial adhesion and invasion levels that were increased more than 100-fold compared to those of normal cells. Inhibition studies confirmed that the capsular sialic acid moiety is responsible for the binding to virus-infected cell surfaces. Also, preincubation of S. suis with swH1N1 significantly increased bacterial adhesion to/invasion of epithelial cells, suggesting that S. suis also uses swH1N1 as a vehicle to invade epithelial cells when the two infections occur simultaneously. Influenza virus infection may facilitate the transient passage of S. suis at the respiratory tract to reach the bloodstream and cause bacteremia and septicemia. S. suis may also increase the local inflammation at the respiratory tract during influenza infection, as suggested by an exacerbated expression of proinflammatory mediators in coinfected cells. These results give new insight into the complex interactions between influenza virus and S. suis in a coinfection model. PMID:24082069

[Bacterial vaginosis in 2011: a lot of questions remain].

PubMed

Bohbot, J-M; Lepargneur, J-P

2012-01-01

Bacterial vaginosis is one of the most frequent vaginal affections. It results from a deep imbalance of the vaginal ecosystem whose mechanisms remain mysterious, even if recent progress were accomplished in their comprehension: if the flora implied in the bacterial vaginosis is recognized like polymorphic, it appears that Gardnerella vaginalis plays a major part with two genomically different forms: a commensal form (slightly adhesive to the epithelial cells), and a pathogenic one (strongly adhesive to the epithelial cells); the changes in lactobacilli are also to take into account: L. iners could be a marker of the vaginal flora imbalance whereas L. crispatus is generally met in the normal vaginal flora. These findings could influence the composition of coming probiotics; it is recognized that bacterial vaginosis is involved in the risk of prematurity but molecular quantification of G. vaginalis (and of Atopobium vaginae) is more sensitive for the diagnosis of BV what could improve the detection of high-risk pregnant women. The isolated antibiotic treatments are not very effective on the prevention of recurrences. The rebalancing of the vaginal flora is essential. In this field, the local estrogens showed some effectiveness. The use of probiotics is promising and can be recommended in complement of the antibiotic treatment even if the results of the clinical studies are still too heterogeneous to lead to precise indications. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Staphylococcus epidermidis biofilm formation and structural organization on different types of intraocular lenses under in vitro flow conditions.

PubMed

Baillif, Stéphanie; Leduff, Frank; Hartmann, Daniel J; Kodjikian, Laurent

2013-01-01

To compare the adherence and structural organization of Staphylococcus epidermidis biofilm on intraocular lenses (IOLs). IOLs made of 3 different biomaterials [polymethyl methacrylate (PMMA), hydrophilic acrylic or hydrophobic acrylic] were incubated into an S. epidermidis bacterial solution. Scanning electron microscopy was used to count the bound bacteria and to analyze the structural biofilm architecture. After 4-6 h of incubation, adherence was statistically weakest on the hydrophilic acrylic polymer. On the hydrophobic acrylic material, the bacterial cells tended to cover the substratum in a horizontal spread in a continuous monolayer. On the hydrophilic acrylic material or on the PMMA material bacterial cells tended to form only few, small scattered cell clusters. The data suggest that the pattern of S. epidermidis adhesion varies with the IOL biomaterial. Hydrophobic IOLs seem to be more permissive to S. epidermidis adhesion. Copyright © 2013 S. Karger AG, Basel.

Antibacterial effect of copper-bearing titanium alloy (Ti-Cu) against Streptococcus mutans and Porphyromonas gingivalis

NASA Astrophysics Data System (ADS)

Liu, Rui; Memarzadeh, Kaveh; Chang, Bei; Zhang, Yumei; Ma, Zheng; Allaker, Robert P.; Ren, Ling; Yang, Ke

2016-07-01

Formation of bacterial biofilms on dental implant material surfaces (titanium) may lead to the development of peri-implant diseases influencing the long term success of dental implants. In this study, a novel Cu-bearing titanium alloy (Ti-Cu) was designed and fabricated in order to efficiently kill bacteria and discourage formation of biofilms, and then inhibit bacterial infection and prevent implant failure, in comparison with pure Ti. Results from biofilm based gene expression studies, biofilm growth observation, bacterial viability measurements and morphological examination of bacteria, revealed antimicrobial/antibiofilm activities of Ti-Cu alloy against the oral specific bacterial species, Streptococcus mutans and Porphyromonas gingivalis. Proliferation and adhesion assays with mesenchymal stem cells, and measurement of the mean daily amount of Cu ion release demonstrated Ti-Cu alloy to be biocompatible. In conclusion, Ti-Cu alloy is a promising dental implant material with antimicrobial/antibiofilm activities and acceptable biocompatibility.

Microbial adhesion to silicone hydrogel lenses: a review.

PubMed

Willcox, Mark D P

2013-01-01

Microbial adhesion to contact lenses is believed to be one of the initiating events in the formation of many corneal infiltrative events, including microbial keratitis, that occur during contact lens wear. The advent of silicone hydrogel lenses has not reduced the incidence of these events. This may partly be related to the ability of microbes to adhere to these lenses. The aim of this study was to review the published literature on microbial adhesion to contact lenses, focusing on adhesion to silicone hydrogel lenses. The literature on microbial adhesion to contact lenses was searched, along with associated literature on adverse events that occur during contact lens wear. Particular reference was paid to the years 1995 through 2012 because this encompasses the time when the first clinical trials of silicone hydrogel lenses were reported, and their commercial availability and the publication of epidemiology studies on adverse events were studied. In vitro studies of bacterial adhesion to unworn silicone hydrogel lens have shown that generally, bacteria adhere to these lenses in greater numbers than to the hydroxyethyl methacrylate-based soft lenses. Lens wear has different effects on microbial adhesion, and this is dependent on the type of lens and microbial species/genera that is studied. Biofilms that can be formed on any lens type tend to protect the bacteria and fungi from the effects on disinfectants. Fungal hyphae can penetrate the surface of most types of lenses. Acanthamoeba adhere in greater numbers to first-generation silicone hydrogel lenses compared with the second-generation or hydroxyethyl methacrylate-based soft lenses. Microbial adhesion to silicone hydrogel lenses occurs and is associated with the production of corneal infiltrative events during lens wear.

Epithelial Microvilli Establish an Electrostatic Barrier to Microbial Adhesion

PubMed Central

Bennett, Kaila M.; Walker, Sharon L.

2014-01-01

Microvilli are membrane extensions on the apical surface of polarized epithelia, such as intestinal enterocytes and tubule and duct epithelia. One notable exception in mucosal epithelia is M cells, which are specialized for capturing luminal microbial particles; M cells display a unique apical membrane lacking microvilli. Based on studies of M cell uptake under different ionic conditions, we hypothesized that microvilli may augment the mucosal barrier by providing an increased surface charge density from the increased membrane surface and associated glycoproteins. Thus, electrostatic charges may repel microbes from epithelial cells bearing microvilli, while M cells are more susceptible to microbial adhesion. To test the role of microvilli in bacterial adhesion and uptake, we developed polarized intestinal epithelial cells with reduced microvilli (“microvillus-minus,” or MVM) but retaining normal tight junctions. When tested for interactions with microbial particles in suspension, MVM cells showed greatly enhanced adhesion and uptake of particles compared to microvillus-positive cells. This preference showed a linear relationship to bacterial surface charge, suggesting that microvilli resist binding of microbes by using electrostatic repulsion. Moreover, this predicts that pathogen modification of electrostatic forces may contribute directly to virulence. Accordingly, the effacement effector protein Tir from enterohemorrhagic Escherichia coli O157:H7 expressed in epithelial cells induced a loss of microvilli with consequent enhanced microbial binding. These results provide a new context for microvillus function in the host-pathogen relationship, based on electrostatic interactions. PMID:24778113

Reduction of Streptococcus mutans adherence and dental biofilm formation by surface treatment with phosphorylated polyethylene glycol.

PubMed

Shimotoyodome, Akira; Koudate, Takashi; Kobayashi, Hisataka; Nakamura, Junji; Tokimitsu, Ichiro; Hase, Tadashi; Inoue, Takashi; Matsukubo, Takashi; Takaesu, Yoshinori

2007-10-01

Initial attachment of the cariogenic Streptococcus mutans onto dental enamel is largely promoted by the adsorption of specific salivary proteins on enamel surface. Some phosphorylated salivary proteins were found to reduce S. mutans adhesion by competitively inhibiting the adsorption of S. mutans-binding salivary glycoproteins to hydroxyapatite (HA). The aim of this study was to develop antiadherence compounds for preventing dental biofilm development. We synthesized phosphorylated polyethylene glycol (PEG) derivatives and examined the possibility of surface pretreatment with them for preventing S. mutans adhesion in vitro and dental biofilm formation in vivo. Pretreatment of the HA surface with methacryloyloxydecyl phosphate (MDP)-PEG prior to saliva incubation hydrophilized the surface and thereby reduced salivary protein adsorption and saliva-promoted bacterial attachment to HA. However, when MDP-PEG was added to the saliva-pretreated HA (S-HA) surface, its inhibitory effect on bacterial binding was completely diminished. S. mutans adhesion onto S-HA was successfully reduced by treatment of the surface with pyrophosphate (PP), which desorbs salivary components from S-HA. Treatment of S-HA surfaces with MDP-PEG plus PP completely inhibited saliva-promoted S. mutans adhesion even when followed by additional saliva treatment. Finally, mouthwash with MDP-PEG plus PP prevented de novo biofilm development after thorough teeth cleaning in humans compared to either water or PP alone. We conclude that MDP-PEG plus PP has the potential for use as an antiadherence agent that prevents dental biofilm development.

Crohn's disease-associated adherent-invasive Escherichia coli adhesion is enhanced by exposure to the ubiquitous dietary polysaccharide maltodextrin.

PubMed

Nickerson, Kourtney P; McDonald, Christine

2012-01-01

Crohn's disease (CD) is associated with intestinal dysbiosis evidenced by an altered microbiome forming thick biofilms on the epithelium. Additionally, adherent-invasive E. coli (AIEC) strains are frequently isolated from ileal lesions of CD patients indicating a potential role for these strains in disease pathogenesis. The composition and characteristics of the host microbiome are influenced by environmental factors, particularly diet. Polysaccharides added to food as emulsifiers, stabilizers or bulking agents have been linked to bacteria-associated intestinal disorders. The escalating consumption of polysaccharides in Western diets parallels an increased incidence of CD during the latter 20(th) century. In this study, the effect of a polysaccharide panel on adhesiveness of the CD-associated AIEC strain LF82 was analyzed to determine if these food additives promote disease-associated bacterial phenotypes. Maltodextrin (MDX), a polysaccharide derived from starch hydrolysis, markedly enhanced LF82 specific biofilm formation. Biofilm formation of multiple other E. coli strains was also promoted by MDX. MDX-induced E. coli biofilm formation was independent of polysaccharide chain length indicating a requirement for MDX metabolism. MDX exposure induced type I pili expression, which was required for MDX-enhanced biofilm formation. MDX also increased bacterial adhesion to human intestinal epithelial cell monolayers in a mechanism dependent on type 1 pili and independent of the cellular receptor CEACAM6, suggesting a novel mechanism of epithelial cell adhesion. Analysis of mucosa-associated bacteria from individuals with and without CD showed increased prevalence of malX, a gene essential for MDX metabolism, uniquely in the ileum of CD patients. These findings demonstrate that the ubiquitous dietary component MDX enhances E. coli adhesion and suggests a mechanism by which Western diets rich in specific polysaccharides may promote dysbiosis of gut microbes and contribute to disease susceptibility.

The activity of ferulic and gallic acids in biofilm prevention and control of pathogenic bacteria.

PubMed

Borges, Anabela; Saavedra, Maria J; Simões, Manuel

2012-01-01

The activity of two phenolic acids, gallic acid (GA) and ferulic acid (FA) at 1000 μg ml(-1), was evaluated on the prevention and control of biofilms formed by Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes. In addition, the effect of the two phenolic acids was tested on planktonic cell susceptibility, bacterial motility and adhesion. Biofilm prevention and control were tested using a microtiter plate assay and the effect of the phenolic acids was assessed on biofilm mass (crystal violet staining) and on the quantification of metabolic activity (alamar blue assay). The minimum bactericidal concentration for P. aeruginosa was 500 μg ml(-1) (for both phenolic acids), whilst for E. coli it was 2500 μg ml(-1) (FA) and 5000 μg ml(-1) (GA), for L. monocytogenes it was >5000 μg ml(-1) (for both phenolic acids), and for S. aureus it was 5000 μg ml(-1) (FA) and >5000 μg ml(-1) (GA). GA caused total inhibition of swimming (L. monocytogenes) and swarming (L. monocytogenes and E. coli) motilities. FA caused total inhibition of swimming (L. monocytogenes) and swarming (L. monocytogenes and E. coli) motilities. Colony spreading of S. aureus was completely inhibited by FA. The interference of GA and FA with bacterial adhesion was evaluated by the determination of the free energy of adhesion. Adhesion was less favorable when the bacteria were exposed to GA (P. aeruginosa, S. aureus and L. monocytogenes) and FA (P. aeruginosa and S. aureus). Both phenolics had preventive action on biofilm formation and showed a higher potential to reduce the mass of biofilms formed by the Gram-negative bacteria. GA and FA promoted reductions in biofilm activity >70% for all the biofilms tested. The two phenolic acids demonstrated the potential to inhibit bacterial motility and to prevent and control biofilms of four important human pathogenic bacteria. This study also emphasizes the potential of phytochemicals as an emergent source of biofilm control products.

Quantification of Staphylococcus aureus adhesion to equine bone surfaces passivated with Plasmalyte and hyperimmune plasma.

PubMed

Bauer, Sandra M; Santschi, Elizabeth M; Fialkowski, James; Clayton, Murray K; Proctor, Richard A

2004-01-01

To quantify the adhesion of Staphylococcus aureus to 4 equine bone surfaces passivated in a balanced polyionic solution (Plasmalyte) or hyperimmune equine plasma (Polymune plasma). In vitro comparative study. Third metacarpal bone (MC3) surface explants from 9 equine cadavers. Approximately 1 cm(2) sections of periosteum were removed from MC3 and stapled to sterile stainless steel screens. Three bone surface explants were cut using a surgical saw to present 1 cm(2) surfaces of subperiosteal bone, cut cortical bone, or endosteum. Duplicate explants of each surface were immersed for 1 hour in Plasmalyte or hyperimmune equine plasma. Each explant was then placed in a well of a 6-well sterile tissue culture plate with the surface of interest exposed. Each surface was inoculated with approximately 100 colony-forming units of S. aureus in 10 microL of Mueller Hinton broth and incubated for 6 hours at 37 degrees C. After gentle rinsing to remove non-adherent bacteria, samples were sonicated for 5 minutes at 60 kHz to loosen adhered bacteria. The number of adherent bacteria was determined by serial dilutions and incubation of the sonicate. Scanning electron microscopy (SEM) was performed on samples identically treated from an additional horse to confirm bacterial removal by sonication from all surfaces and support quantitative culture results. Less S. aureus adhered to periosteum than to cortical bone, cut cortical bone, and endosteal surfaces, which were all similar. Exposure of all surfaces to hyperimmune plasma reduced S. aureus adherence compared with Plasmalyte exposure; SEM supported these conclusions. Less bacteria adhere to periosteum than other bone surfaces. Hyperimmune plasma reduces bacterial adhesion to all bone tissue surfaces. Understanding the factors that affect bacterial adhesion to bone will facilitate development of improved intraoperative lavage solutions to reduce the morbidity and mortality associated with postoperative infection.

Chemical modification of polyvinyl chloride and silicone elastomer in inhibiting adhesion of Aeromonas hydrophila.

PubMed

Kregiel, Dorota; Berlowska, Joanna; Mizerska, Urszula; Fortuniak, Witold; Chojnowski, Julian; Ambroziak, Wojciech

2013-07-01

Disease-causing bacteria of the genus Aeromonas are able to adhere to pipe materials, colonizing the surfaces and forming biofilms in water distribution systems. The aim of our research was to study how the modification of materials used commonly in the water industry can reduce bacterial cell attachment. Polyvinyl chloride and silicone elastomer surfaces were activated and modified with reactive organo-silanes by coupling or co-crosslinking silanes with the native material. Both the native and modified surfaces were tested using the bacterial strain Aeromonas hydrophila, which was isolated from the Polish water distribution system. The surface tension of both the native and modified surfaces was measured. To determine cell viability and bacterial adhesion two methods were used, namely plate count and luminometry. Results were expressed in colony-forming units (c.f.u.) and in relative light units (RLU) per cm(2). Almost all the chemically modified surfaces exhibited higher anti-adhesive and anti-microbial properties in comparison to the native surfaces. Among the modifying agents examined, poly[dimethylsiloxane-co-(N,N-dimethyl-N-n-octylammoniopropyl chloride) methylsiloxane)] terminated with hydroxydimethylsilyl groups (20 %) in silicone elastomer gave the most desirable results. The surface tension of this modifier, was comparable to the non-polar native surface. However, almost half of this value was due to the result of polar forces. In this case, in an adhesion analysis, only 1 RLU cm(-2) and less than 1 c.f.u. cm(-2) were noted. For the native gumosil, the results were 9,375 RLU cm(-2) and 2.5 × 10(8) c.f.u. cm(-2), respectively. The antibacterial activity of active organo-silanes was associated only with the carrier surface because no antibacterial compounds were detected in liquid culture media, in concentrations that were able to inhibit cell growth.

Quorum-sensing regulation governs bacterial adhesion, biofilm development, and host colonization in Pantoea stewartii subspecies stewartii.

PubMed

Koutsoudis, Maria D; Tsaltas, Dimitrios; Minogue, Timothy D; von Bodman, Susanne B

2006-04-11

The phytopathogenic bacterium Pantoea stewartii subsp. stewartii synthesizes stewartan exo/capsular polysaccharide (EPS) in a cell density-dependent manner governed by the EsaI/EsaR quorum-sensing (QS) system. This study analyzes biofilm development and host colonization of the WT and QS regulatory mutant strains of P. stewartii. First, we show that the cell density-dependent synthesis of stewartan EPS, governed by the EsaI/EsaR QS system, is required for proper bacterial adhesion and development of spatially defined, 3D biofilms. Second, a nonvirulent mutant lacking the esaI gene adheres strongly to surfaces and develops densely packed, less structurally defined biofilms in vitro. This strain appears to be arrested in a low cell density developmental mode. Exposure of this strain to exogenous N-acyl-homoserine lactone counteracts this adhesion phenotype. Third, QS mutants lacking the EsaR repressor attach poorly to surfaces and form amorphous biofilms heavily enmeshed in excess EPS. Fourth, the WT strain disseminates efficiently within the xylem, primarily in a basipetal direction. In contrast, the two QS mutant strains remain largely localized at the site of infection. Fifth, and most significantly, epifluorescence microscopic imaging of infected leaf tissue and excised xylem vessels reveals that the bacteria colonize the xylem with unexpected specificity, particularly toward the annular rings and spiral secondary wall thickenings of protoxylem, as opposed to indiscriminate growth to fill the xylem lumen. These observations are significant to bacterial plant pathogenesis in general and may reveal targets for disease control.

Quorum-sensing regulation governs bacterial adhesion, biofilm development, and host colonization in Pantoea stewartii subspecies stewartii

PubMed Central

Koutsoudis, Maria D.; Tsaltas, Dimitrios; Minogue, Timothy D.; von Bodman, Susanne B.

2006-01-01

The phytopathogenic bacterium Pantoea stewartii subsp. stewartii synthesizes stewartan exo/capsular polysaccharide (EPS) in a cell density-dependent manner governed by the EsaI/EsaR quorum-sensing (QS) system. This study analyzes biofilm development and host colonization of the WT and QS regulatory mutant strains of P. stewartii. First, we show that the cell density-dependent synthesis of stewartan EPS, governed by the EsaI/EsaR QS system, is required for proper bacterial adhesion and development of spatially defined, 3D biofilms. Second, a nonvirulent mutant lacking the esaI gene adheres strongly to surfaces and develops densely packed, less structurally defined biofilms in vitro. This strain appears to be arrested in a low cell density developmental mode. Exposure of this strain to exogenous N-acyl-homoserine lactone counteracts this adhesion phenotype. Third, QS mutants lacking the EsaR repressor attach poorly to surfaces and form amorphous biofilms heavily enmeshed in excess EPS. Fourth, the WT strain disseminates efficiently within the xylem, primarily in a basipetal direction. In contrast, the two QS mutant strains remain largely localized at the site of infection. Fifth, and most significantly, epifluorescence microscopic imaging of infected leaf tissue and excised xylem vessels reveals that the bacteria colonize the xylem with unexpected specificity, particularly toward the annular rings and spiral secondary wall thickenings of protoxylem, as opposed to indiscriminate growth to fill the xylem lumen. These observations are significant to bacterial plant pathogenesis in general and may reveal targets for disease control. PMID:16585516

Bacteria as living patchy colloids: Phenotypic heterogeneity in surface adhesion

PubMed Central

Hermes, Michiel; Schwarz-Linek, Jana; Poon, Wilson C. K.

2018-01-01

Understanding and controlling the surface adhesion of pathogenic bacteria is of urgent biomedical importance. However, many aspects of this process remain unclear (for example, microscopic details of the initial adhesion and possible variations between individual cells). Using a new high-throughput method, we identify and follow many single cells within a clonal population of Escherichia coli near a glass surface. We find strong phenotypic heterogeneities: A fraction of the cells remain in the free (planktonic) state, whereas others adhere with an adhesion strength that itself exhibits phenotypic heterogeneity. We explain our observations using a patchy colloid model; cells bind with localized, adhesive patches, and the strength of adhesion is determined by the number of patches: Nonadherers have no patches, weak adherers bind with a single patch only, and strong adherers bind via a single or multiple patches. We discuss possible implications of our results for controlling bacterial adhesion in biomedical and other applications. PMID:29719861

A comparative study of the adhesion of biosynthesized gold and conjugated gold/prodigiosin nanoparticles to triple negative breast cancer cells.

PubMed

Dozie-Nwachukwu, S O; Obayemi, J D; Danyuo, Y; Anuku, N; Odusanya, O S; Malatesta, K; Soboyejo, W O

2017-08-17

This paper explores the adhesion of biosynthesized gold nanoparticles (AuNPs) and gold (Au) nanoparticle/prodigiosin (PG) drug nanoparticles to breast cancer cells (MDA-MB-231 cells). The AuNPs were synthesized in a record time (less than 30 s) from Nauclea latifolia leaf extracts, while the PG was produced via bacterial synthesis with Serratia marcescens sp. The size distributions and shapes of the resulting AuNPs were characterized using transmission electron microscopy (TEM), while the resulting hydrodynamic diameters and polydispersity indices were studied using dynamic light scattering (DLS). Atomic Force Microscopy (AFM) was used to study the adhesion between the synthesized gold nanoparticles (AuNPs)/LHRH-conjugated AuNPs and triple negative breast cancer cells (MDA-MB-231 cells), as well as the adhesion between LHRH-conjugated AuNP/PG drug and MDA-MB-231 breast cancer cells. The adhesion forces between LHRH-conjugated AuNPs and breast cancer cells are shown to be five times greater than those between AuNPs and normal breast cells. The increase in adhesion is shown to be due to the over-expression of LHRH receptors on the surfaces of MDA-MB-231 breast cancer cells, which was revealed by confocal immuno-fluorescence microscopy. The implications of the results are then discussed for the selective and specific targeting and treatment of triple negative breast cancer.

Mechanism of microbial flotation using Thiobacillus ferrooxidans for pyrite suppression.

PubMed

Ohmura, N; Kitamura, K; Saiki, H

1993-03-15

Microbial desulfurization might be developed as a new process for the removal of pyrite sulfur from coal sluries such as coal-water mixture (CWM). An application of iron-oxidizing bacterium Thiobacillus ferrooxidans to flotation would shorten the periods of the microbial removal of pyrite from some weeks by leaching methods to a few minutes. The floatability of pyrite in flotation was mainly reduced by T. ferrooxidans itself rather than by other microbial substances in bacterial culture as additive of flotation liquor. Floatability was suppressed within a few seconds by bacterial contact. The suppression was proportional to increasing the number of cells observed between bacterial adhesion and the suppression of floatability. If 25% of the total pyrite surface area covered with the bacteria, pyrite floatability would be completely depressed. Bacteria that lost their iron-oxidizing activities by sodium cyanide treatment were also able to adhere to pyrite and reduced pyrite floatability as much as normal bacteria did. Thiobacillus ferrooxidans ATCC 23270, T-1, 9, and 11, which had different iron-oxidizing abilities, suppressed floatability to similar-levels. The oxidizing ability of bacteria did not influence the suppressing effect. These results showed the mechanism of the suppression of pyrite floatability by bacteria. Quick bacterial adhesion to pyrite induced floatability suppression by changing the surface property from hydrophobic. The quick adhesion of the bacterium was the novel function which worked to change the surface property of pyrite to remove it from coal. (c) 1993 John Wiley & Sons, Inc.

Adhesive capabilities of Staphylococcus aureus and Pseudomonas aeruginosa isolated from tears of HIV/AIDS patients to soft contact lenses.

PubMed

Ajayi, B O; Kio, F E; Otajevwo, F D

2012-01-01

Fifty conjunctival swab samples collected from ELISA confirmed HIV/AIDS seropositive patients who were referred to the HIV/AIDS laboratories of the University of Benin Teaching Hospital and Central Hospital both based in Benin City, Nigeria were aseptically cultured on appropriate media by standard methods. The resulting isolates/strains, after identification by standard methods, were tested for their ability to adhere to two hydrophobic non-ionic daily wear silicone hydrogel soft contact lenses (i.e. lotrafilcon B, WC 33% and polymacon, WC 38%) as well as to two hydrophilic ionic conventional extended wear silicone hydrogel soft contact lenses (i.e. methafilcon A, WC 55% and omafilcon A, WC 60%) by the adhesiveness/slime production modified vortex/Robin device method. Evidence of adhesiveness/slime production was indicated by presence of a visible stained film lining the surface of the contact lens which was measured and recorded as strong or weak according to the density of the adhered bacterial film. Fourteen (28.0%) Staphylococcus aureus strains and 10 (20.0%) Pseudomonas aeruginosa strains were obtained among other organisms. Staphylococcus aureus strains adhered in decreasing order to lotrafilcon B (55.4 ± 4.7), polymacon (46.4 ± 8.4), methfilcon A (46.4 ± 8.4) and omafilcon A (25.0 ± 6.4) with no significant difference in adhesive strengths of individual strains (P > 0.05). Pseudomonas aeruginosa strains also recorded decreasing adhesive strengths to lotrafilcon B (37.5 ± 8.2), polymacon (28.6 ± 6.3), methafilcon A (26.8 ± 5.5) and omafilcon A (23.2 ± 5.5) also with no significant difference in adhesive strengths of individual strains (P > 0.05). Attachment strengths of Staph. aureus strains to all four contact lenses were higher than those of Pseudomonas aeruginosa strains. Both organisms adhered most to hydrophobic lotrafilcon B and least to hydrophilic omafilcon A. This invitro adhesion studies revealed that daily wear silicone hydrogel low water content, non-ionic contact lenses are more prone to bacterial adhesion than the conventional extended wear hydrogel high water content, ionic contact lenses and hence, there is more risk of microbial adhesion to the former compared to the latter. Other implications are highlighted.

Adhesive Capabilities of Staphylococcus Aureus and Pseudomonas Aeruginosa Isolated from Tears of HIV/AIDS Patients to Soft Contact Lenses

PubMed Central

B. O., Ajayi; F.E., Kio; F.D., Otajevwo

2012-01-01

Fifty conjunctival swab samples collected from ELISA confirmed HIV/AIDS seropositive patients who were referred to the HIV/AIDS laboratories of the University of Benin Teaching Hospital and Central Hospital both based in Benin City, Nigeria were aseptically cultured on appropriate media by standard methods. The resulting isolates/strains, after identification by standard methods, were tested for their ability to adhere to two hydrophobic non-ionic daily wear silicone hydrogel soft contact lenses (i.e. lotrafilcon B, WC 33% and polymacon, WC 38%) as well as to two hydrophilic ionic conventional extended wear silicone hydrogel soft contact lenses (i.e. methafilcon A, WC 55% and omafilcon A, WC 60%) by the adhesiveness/slime production modified vortex/Robin device method. Evidence of adhesiveness/slime production was indicated by presence of a visible stained film lining the surface of the contact lens which was measured and recorded as strong or weak according to the density of the adhered bacterial film. Fourteen (28.0%) Staphylococcus aureus strains and 10 (20.0%) Pseudomonas aeruginosa strains were obtained among other organisms. Staphylococcus aureus strains adhered in decreasing order to lotrafilcon B (55.4 ± 4.7), polymacon (46.4 ± 8.4), methfilcon A (46.4 ± 8.4) and omafilcon A (25.0 ± 6.4) with no significant difference in adhesive strengths of individual strains (P > 0.05). Pseudomonas aeruginosa strains also recorded decreasing adhesive strengths to lotrafilcon B (37.5 ± 8.2), polymacon (28.6 ± 6.3), methafilcon A (26.8 ± 5.5) and omafilcon A (23.2 ± 5.5) also with no significant difference in adhesive strengths of individual strains (P > 0.05). Attachment strengths of Staph. aureus strains to all four contact lenses were higher than those of Pseudomonas aeruginosa strains. Both organisms adhered most to hydrophobic lotrafilcon B and least to hydrophilic omafilcon A. This invitro adhesion studies revealed that daily wear silicone hydrogel low water content, non-ionic contact lenses are more prone to bacterial adhesion than the conventional extended wear hydrogel high water content, ionic contact lenses and hence, there is more risk of microbial adhesion to the former compared to the latter. Other implications are highlighted. PMID:22980120

Adhesion Potential of Intestinal Microbes Predicted by Physico-Chemical Characterization Methods

PubMed Central

Niederberger, Tobias; Fischer, Peter; Rühs, Patrick Alberto

2015-01-01

Bacterial adhesion to epithelial surfaces affects retention time in the human gastro-intestinal tract and therefore significantly contributes to interactions between bacteria and their hosts. Bacterial adhesion among other factors is strongly influenced by physico-chemical factors. The accurate quantification of these physico-chemical factors in adhesion is however limited by the available measuring techniques. We evaluated surface charge, interfacial rheology and tensiometry (interfacial tension) as novel approaches to quantify these interactions and evaluated their biological significance via an adhesion assay using intestinal epithelial surface molecules (IESM) for a set of model organisms present in the human gastrointestinal tract. Strain pairs of Lactobacillus plantarum WCFS1 with its sortase knockout mutant Lb. plantarum NZ7114 and Lb. rhamnosus GG with Lb. rhamnosus DSM 20021T were used with Enterococcus faecalis JH2-2 as control organism. Intra-species comparison revealed significantly higher abilities for Lb. plantarum WCSF1 and Lb. rhamnosus GG vs. Lb. plantarum NZ7114 and Lb. rhamnosus DSM 20021T to dynamically increase interfacial elasticity (10−2 vs. 10−3 Pa*m) and reduce interfacial tension (32 vs. 38 mN/m). This further correlated for Lb. plantarum WCSF1 and Lb. rhamnosus GG vs. Lb. plantarum NZ7114 and Lb. rhamnosus DSM 20021T with the decrease of relative hydrophobicity (80–85% vs. 57–63%), Zeta potential (-2.9 to -4.5 mV vs. -8.0 to -13.8 mV) and higher relative adhesion capacity to IESM (3.0–5.0 vs 1.5–2.2). Highest adhesion to the IESM collagen I and fibronectin was found for Lb. plantarum WCFS1 (5.0) and E. faecalis JH2-2 (4.2) whereas Lb. rhamnosus GG showed highest adhesion to type II mucus (3.8). Significantly reduced adhesion (2 fold) to the tested IESM was observed for Lb. plantarum NZ7114 and Lb. rhamnosus DSM 20021T corresponding with lower relative hydrophobicity, Zeta potential and abilities to modify interfacial elasticity and tension. Conclusively, the use of Zeta potential, interfacial elasticity and interfacial tension are proposed as suitable novel descriptive and predictive parameters to study the interactions of intestinal microbes with their hosts. PMID:26295945

Efficacy of a mouthrinse based on hydroxyapatite to reduce initial bacterial colonisation in situ.

PubMed

Kensche, A; Holder, C; Basche, S; Tahan, N; Hannig, C; Hannig, M

2017-08-01

The present in situ - investigation aimed to specify the impact of pure hydroxyapatite microclusters on initial bioadhesion and bacterial colonization at the tooth surface. Pellicle formation was carried out in situ on bovine enamel slabs (9 subjects). After 1min of pellicle formation rinses with 8ml of hydroxyapatite (HA) microclusters (5%) in bidestilled water or chlorhexidine 0.2% were performed. As negative control no rinse was adopted. In situ biofilm formation was promoted by the intraoral slab exposure for 8h overnight. Afterwards initial bacterial adhesion was quantified by DAPI staining and bacterial viability was determined in vivo/in vitro by live/dead-staining (BacLight). SEM analysis evaluated the efficacy of the mouthrinse to accumulate hydroxyapatite microclusters at the specimens' surface and spit-out samples of the testsolution were investigated by TEM. Compared to the control (2.36×10 6 ±2.01×10 6 bacteria/cm 2 ), significantly reduced amounts of adherent bacteria were detected on specimens rinsed with chlorhexidine 0.2% (8.73×10 4 ±1.37×10 5 bacteria/cm 2 ) and likewise after rinses with the hydroxyapatite testsolution (2.08×10 5 ±2.85×10 5 bacteria/cm 2 , p<0.001). No demonstrable effect of HA-particles on Streptococcus mutans viability could be shown. SEM analysis confirmed the temporary adsorption of hydroxyapatite microclusters at the tooth surface. Adhesive interactions of HA-particles with oral bacteria were shown by TEM. Hydroxyapatite microclusters reduced initial bacterial adhesion to enamel in situ considerably and could therefore sensibly supplement current approaches in dental prophylaxis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bacterial adherence and biofilm formation on medical implants: a review.

PubMed

Veerachamy, Suganthan; Yarlagadda, Tejasri; Manivasagam, Geetha; Yarlagadda, Prasad Kdv

2014-10-01

Biofilms are a complex group of microbial cells that adhere to the exopolysaccharide matrix present on the surface of medical devices. Biofilm-associated infections in the medical devices pose a serious problem to the public health and adversely affect the function of the device. Medical implants used in oral and orthopedic surgery are fabricated using alloys such as stainless steel and titanium. The biological behavior, such as osseointegration and its antibacterial activity, essentially depends on both the chemical composition and the morphology of the surface of the device. Surface treatment of medical implants by various physical and chemical techniques are attempted in order to improve their surface properties so as to facilitate bio-integration and prevent bacterial adhesion. The potential source of infection of the surrounding tissue and antimicrobial strategies are from bacteria adherent to or in a biofilm on the implant which should prevent both biofilm formation and tissue colonization. This article provides an overview of bacterial biofilm formation and methods adopted for the inhibition of bacterial adhesion on medical implants. © IMechE 2014.

Screening of immunomodulatory and adhesive Lactobacillus with antagonistic activities against Salmonella from fermented vegetables.

PubMed

Feng, Junchang; Liu, Pilong; Yang, Xin; Zhao, Xin

2015-12-01

The purpose of this study was to select strains of lactic acid bacteria (LAB) by their in vitro adhesive and immunomodulatory properties for potential use as probiotics. In this study, 16 randomly selected LAB strains from fermented vegetables (sauerkraut, bean and cabbage) were first screened for their tolerance to acid, bile salts, pepsin and pancreatin, bacterial inhibitory activities and abilities to adherence to Caco-2 cells. Then, 4 strains with the highest adhesion abilities were selected for further studies of their immunomodulatory properties and inhibitory effects against Salmonella adhesion and invasion to Caco-2 cells in vitro. The results showed that these 16 LAB strains effectively survived in simulated gastrointestinal condition and inhibited growth of six tested pathogens. Lactobacillus rhamnosus P1, Lactobacillus plantarum P2, Lactobacillus rhamnosus P3 and Lactobacillus casei P4 had the highest abilities to adhere to Caco-2 cells. Furthermore, L. plantarum P2 strain showed higher abilities to induce expression of tumor necrosis factor-α and interleukin-12 by splenic monocytes and strongly inhibited the adhesion and invasion of S. enteritidis ATCC13076 to Caco-2 cells. These results suggest that Lactobacillus strains P2 could be used as a probiotic candidate in food against Salmonella infection.

Effect of flagella expression on adhesion of Achromobacter piechaudii to chalk surfaces.

PubMed

Nejidat, A; Saadi, I; Ronen, Z

2008-12-01

To examine flagella role and cell motility in adhesion of Achromobacter piechaudii to chalk. Transmission electron microscopy revealed that stationary cells have thicker and longer flagella than logarithmic cells. SDS-PAGE analysis showed that flagellin was more abundant in stationary cells than logarithmic ones. Sonication or inhibition of flagellin synthesis caused a 30% reduction in adhesion to chalk. Preincubation of chalk with flagella extracts reduced adhesion, by 50%. Three motility mutants were isolated. Mutants 94 and 153 were nonmotile, expressed normal levels of flagellin, have regular flagella and exhibited reduced adhesion. Mutant 208 expressed low levels of flagellin, no flagella and a spherical cell shape but with normal adhesion capacity. Multiple cell surface factors affect the adhesion efficiency to chalk. Flagella per se through physical interaction and through cell motility contribute to the adhesion process. The adhesion behaviour of mutant 208 suggests that cell shape can compensate for flagellar removal and motility. Physiological status affects bacterial cell surface properties and hence adhesion efficiency to chalk. This interaction is essential to sustain biodegradation activities and thus, remediation of contaminated chalk aquifers.

Listeria monocytogenes uses Listeria adhesion protein (LAP) to promote bacterial transepithelial translocation and induces expression of LAP receptor Hsp60.

PubMed

Burkholder, Kristin M; Bhunia, Arun K

2010-12-01

Listeria monocytogenes interaction with the intestinal epithelium is a key step in the infection process. We demonstrated that Listeria adhesion protein (LAP) promotes adhesion to intestinal epithelial cells and facilitates extraintestinal dissemination in vivo. The LAP receptor is a stress response protein, Hsp60, but the precise role for the LAP-Hsp60 interaction during Listeria infection is unknown. Here we investigated the influence of physiological stressors and Listeria infection on host Hsp60 expression and LAP-mediated bacterial adhesion, invasion, and transepithelial translocation in an enterocyte-like Caco-2 cell model. Stressors such as heat (41°C), tumor necrosis factor alpha (TNF-α) (100 U), and L. monocytogenes infection (10(4) to 10(6) CFU/ml) significantly (P < 0.05) increased plasma membrane and intracellular Hsp60 levels in Caco-2 cells and consequently enhanced LAP-mediated L. monocytogenes adhesion but not invasion of Caco-2 cells. In transepithelial translocation experiments, the wild type (WT) exhibited 2.7-fold more translocation through Caco-2 monolayers than a lap mutant, suggesting that LAP is involved in transepithelial translocation, potentially via a paracellular route. Short hairpin RNA (shRNA) suppression of Hsp60 in Caco-2 cells reduced WT adhesion and translocation 4.5- and 3-fold, respectively, while adhesion remained unchanged for the lap mutant. Conversely, overexpression of Hsp60 in Caco-2 cells enhanced WT adhesion and transepithelial translocation, but not those of the lap mutant. Furthermore, initial infection with a low dosage (10(6) CFU/ml) of L. monocytogenes increased plasma membrane and intracellular expression of Hsp60 significantly, which rendered Caco-2 cells more susceptible to subsequent LAP-mediated adhesion and translocation. These data provide insight into the role of LAP as a virulence factor during intestinal epithelial infection and pose new questions regarding the dynamics between the host stress response and pathogen infection.

High-Throughput Fabrication Method for Producing a Silver-Nanoparticles-Doped Nanoclay Polymer Composite with Novel Synergistic Antibacterial Effects at the Material Interface.

PubMed

Cai, Shaobo; Pourdeyhimi, Behnam; Loboa, Elizabeth G

2017-06-28

In this study, we report a high-throughput fabrication method at industrial pilot scale to produce a silver-nanoparticles-doped nanoclay-polylactic acid composite with a novel synergistic antibacterial effect. The obtained nanocomposite has a significantly lower affinity for bacterial adhesion, allowing the loading amount of silver nanoparticles to be tremendously reduced while maintaining satisfactory antibacterial efficacy at the material interface. This is a great advantage for many antibacterial applications in which cost is a consideration. Furthermore, unlike previously reported methods that require additional chemical reduction processes to produce the silver-nanoparticles-doped nanoclay, an in situ preparation method was developed in which silver nanoparticles were created simultaneously during the composite fabrication process by thermal reduction. This is the first report to show that altered material surface submicron structures created with the loading of nanoclay enables the creation of a nanocomposite with significantly lower affinity for bacterial adhesion. This study provides a promising scalable approach to produce antibacterial polymeric products with minimal changes to industry standard equipment, fabrication processes, or raw material input cost.

Modulating macrophage response to biomaterials

NASA Astrophysics Data System (ADS)

Zaveri, Toral

Macrophages recruited to the site of biomaterial implantation are the primary mediators of the chronic foreign body response to implanted materials. Since foreign body response limits performance and functional life of numerous implanted biomaterials/medical devices, various approaches have been investigated to modulate macrophage interactions with biomaterial surfaces to mitigate this response. In this work we have explored two independent approaches to modulate the macrophage inflammatory response to biomaterials. The first approach targets surface integrins, cell surface receptors that mediate cell adhesion to biomaterials through adhesive proteins spontaneously adsorbed on biomaterial surfaces. The second approach involves surface modification of biomaterials using nanotopographic features since nanotopography has been reported to modulate cell adhesion and viability in a cell type-dependent manner. More specifically, Zinc Oxide (ZnO) nanorod surface was investigated for its role in modulating macrophage adhesion and survival in vitro and foreign body response in vivo. For the first approach, we have investigated the role of integrin Mac-1 and RGD-binding integrins in the in-vivo osteolysis response and macrophage inflammatory processes of phagocytosis as well as inflammatory cytokine secretion in response to particulate biomaterials. We have also investigated the in vivo foreign body response (FBR) to subcutaneously implanted biomaterials by evaluating the thickness of fibrous capsule formed around the implants after 2 weeks of implantation. The role of Mac-1 integrin was isolated using a Mac-1 KO mouse and comparing it to a WT control. The role of RGD binding integrins in FBR was investigated by coating the implanted biomaterial with ELVAX(TM) polymer loaded with Echistatin which contains the RGD sequence. For the in-vivo osteolysis study and to study the in-vitro macrophage response to particulate biomaterials, we used the RGD peptide encapsulated in ELVAX(TM) and dissolved in macrophage media respectively. By studying the phagocytosis, inflammatory and FBR of macrophages from integrin knockout mice, as well as using various integrin blocking techniques we aim to identify the role of various integrins in macrophage inflammatory response. These integrins can serve as therapeutic targets for mitigating this inflammatory response and improve functional life of implanted biomaterials. Zinc oxide (ZnO) has been investigated in a number of biomedical applications and surfaces presenting well-controlled nanorod structures of ZnO have recently been developed. In order to investigate the influence of nanotopography on macrophage adhesive response, we evaluated macrophage adhesion and viability on ZnO nanorods, compared to a relatively flat sputtered ZnO controls and using glass substrates for reference. We found that although macrophages are capable of initially adhering to and spreading on ZnO nanorod substrates, the number of adherent macrophages on ZnO nanorods was reduced compared to ZnO flat substrate and glass. While these data suggest nanotopography may modulate macrophage adhesion, reduced cell viability on both sputtered and nanorod ZnO substrate indicates appreciable toxicity associated with ZnO. In order to determine long-term physiological responses, ZnO nanorodcoated and sputtered ZnO-coated polyethylene terephthalate (PET) discs were implanted subcutaneously in mice for 14 days. Upon implantation, both ZnO-coated discs resulted in a discontinuous cellular fibrous capsule indicative of unresolved inflammation, in contrast to uncoated PET discs, which resulted in typical foreign body capsule formation. Hence although ZnO substrates presenting nanorod topography have previously been shown to modulate cellular adhesion in a topography-dependent fashion for specific cell types, this work demonstrates that for primary murine macrophages, cell adhesion and viability correlate to both nanotopography and toxicity of dissolved Zn, parameters which are likely interdependent. Considering the toxicity of ZnO nanorod surface towards macrophages, their role as an antibacterial surface was explored. Antibacterial coating approaches are being investigated to modify implants to reduce bacterial adhesion and viability in order to reduce implant-associated infection. To assess the efficacy of ZnO nanorod surfaces as an anti-bacterial coating, we evaluated bacterial adhesion and viability, compared to sputtered ZnO and glass substrates. Common implant-associated pathogens, Pseudomonas aeruginosa and Staphylococcus epidermidis were investigated. ZnO nanorod surface and sputtered ZnO demonstrated a significant bactericidal effect, killing respectively 2.5x and 1.7x times the number of bacteria dead on glass. A similar bactericidal effect of ZnO substrates on S. epidermidis was also evident, with sputtered ZnO and ZnO nanorod substrates killing respectively 22x and 32x times bacteria dead on glass. These data support the further investigation of ZnO nanorod coatings for bacterial adhesion resistance and bactericidal properties.

Sponge-Inspired Dibromohemibastadin Prevents and Disrupts Bacterial Biofilms without Toxicity

PubMed Central

Le Norcy, Tiffany; Niemann, Hendrik; Proksch, Peter; Tait, Karen; Linossier, Isabelle; Réhel, Karine; Hellio, Claire; Faÿ, Fabienne

2017-01-01

Since the banning of several families of compounds in antifouling (AF) coatings, the search for environmentally friendly AF compounds has intensified. Natural sources of AF compounds have been identified in marine organisms and can be used to create analogues in laboratory. In a previous study, we identified that dibromohemibastadin-1 (DBHB) is a promising AF molecule, leading to the inhibition of the activity of phenoloxidase, an enzyme involved in the attachment of mussels to surfaces. This paper describes the activity of the DBHB on biofilm formation and its detachment and on bacterial adhesion and communication: quorum sensing. DBHB has an anti-biofilm activity without affecting adhesion of marine and terrestrial bacteria at a dose of 10 µM. Moreover, DBHB activity on quorum sensing (QS) is demonstrated at doses of 8 and 16 µM. The activity of DBHB on QS is compared to kojic acid, a quorum sensing inhibitor already described. This compound is a promising environmentally friendly molecule potentially useful for the inhibition of microfouling. PMID:28704947

In Vivo Consumption of Cranberry Exerts ex Vivo Antiadhesive Activity against FimH-Dominated Uropathogenic Escherichia coli: A Combined in Vivo, ex Vivo, and in Vitro Study of an Extract from Vaccinium macrocarpon.

PubMed

Rafsanjany, Nasli; Senker, Jandirk; Brandt, Simone; Dobrindt, Ulrich; Hensel, Andreas

2015-10-14

For investigation of the molecular interaction of cranberry extract with adhesins of uropathogenic Escherichia coli (UPEC), urine from four volunteers consuming standardized cranberry extract (proanthocyanidin content = 1.24%) was analyzed within ex vivo experiments, indicating time-dependent significant inhibition of 40-50% of bacterial adhesion of UPEC strain NU14 to human T24 bladder cells. Under in vitro conditions a dose-dependent increase in bacterial adhesion was observed with proanthocyanidin-enriched cranberry Vaccinium macrocarpon extract (proanthocyanidin content = 21%). Confocal laser scanning microscopy and scanning electron microscopy proved that V.m. extract led to the formation of bacterial clusters on the outer plasma membrane of the host cells without subsequent internalization. This agglomerating activity was not observed when a PAC-depleted extract (V.m. extract(≠PAC)) was used, which showed significant inhibition of bacterial adhesion in cases where type 1 fimbriae dominated and mannose-sensitive UPEC strain NU14 was used. V.m. extract(≠PAC) had no inhibitory activity against P- and F1C-fimbriae dominated strain 2980. Quantitative gene expression analysis indicated that PAC-containing as well as PAC-depleted cranberry extracts increased the fimH expression in NU14 as part of a feedback mechanism after blocking FimH. For strain 2980 the PAC-containing extract led to up-regulation of P- and F1C-fimbriae, whereas the PAC-depleted extract had no influence on gene expression. V.m. and V.m. extract(≠PAC) did not influence biofilm and curli formation in UPEC strains NU14 and 2980. These data lead to the conclusion that also proanthocyanidin-free cranberry extracts exert antiadhesive activity by interaction with mannose-sensitive type 1 fimbriae of UPEC.

Bacteria attenuation by iron electrocoagulation governed by interactions between bacterial phosphate groups and Fe(III) precipitates.

PubMed

Delaire, Caroline; van Genuchten, Case M; Amrose, Susan E; Gadgil, Ashok J

2016-10-15

Iron electrocoagulation (Fe-EC) is a low-cost process in which Fe(II) generated from an Fe(0) anode reacts with dissolved O2 to form (1) Fe(III) precipitates with an affinity for bacterial cell walls and (2) bactericidal reactive oxidants. Previous work suggests that Fe-EC is a promising treatment option for groundwater containing arsenic and bacterial contamination. However, the mechanisms of bacteria attenuation and the impact of major groundwater ions are not well understood. In this work, using the model indicator Escherichia coli (E. coli), we show that physical removal via enmeshment in EC precipitate flocs is the primary process of bacteria attenuation in the presence of HCO3(-), which significantly inhibits inactivation, possibly due to a reduction in the lifetime of reactive oxidants. We demonstrate that the adhesion of EC precipitates to cell walls, which results in bacteria encapsulation in flocs, is driven primarily by interactions between EC precipitates and phosphate functional groups on bacteria surfaces. In single solute electrolytes, both P (0.4 mM) and Ca/Mg (1-13 mM) inhibited the adhesion of EC precipitates to bacterial cell walls, whereas Si (0.4 mM) and ionic strength (2-200 mM) did not impact E. coli attenuation. Interestingly, P (0.4 mM) did not affect E. coli attenuation in electrolytes containing Ca/Mg, consistent with bivalent cation bridging between bacterial phosphate groups and inorganic P sorbed to EC precipitates. Finally, we found that EC precipitate adhesion is largely independent of cell wall composition, consistent with comparable densities of phosphate functional groups on Gram-positive and Gram-negative cells. Our results are critical to predict the performance of Fe-EC to eliminate bacterial contaminants from waters with diverse chemical compositions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Antibacterial activity of DLC films containing TiO2 nanoparticles.

PubMed

Marciano, F R; Lima-Oliveira, D A; Da-Silva, N S; Diniz, A V; Corat, E J; Trava-Airoldi, V J

2009-12-01

Diamond-like carbon (DLC) films have been the focus of extensive research in recent years due to their potential applications as surface coatings on biomedical devices. Titanium dioxide (TiO2) in the anatase crystalline form is a strong bactericidal agent when exposed to near-UV light. In this work we investigate the bactericidal activity of DLC films containing TiO2 nanoparticles. The films were grown on 316L stainless-steel substrates from a dispersion of TiO2 in hexane using plasma-enhanced chemical vapor deposition. The composition, bonding structure, surface energy, stress, and surface roughness of these films were also evaluated. The antibacterial tests were performed against Escherichia coli (E. coli) and the results were compared to the bacterial adhesion force to the studied surfaces. The presence of TiO2 in DLC bulk was confirmed by Raman spectroscopy. As TiO2 content increased, I(D)/I(G) ratio, hydrogen content, and roughness also increased; the films became more hydrophilic, with higher surface free energy and the interfacial energy of bacteria adhesion decreased. Experimental results show that TiO2 increased DLC bactericidal activity. Pure DLC films were thermodynamically unfavorable to bacterial adhesion. However, the chemical interaction between the E. coli and the studied films increased for the films with higher TiO2 concentration. As TiO2 bactericidal activity starts its action by oxidative damage to the bacteria wall, a decrease in the interfacial energy of bacteria adhesion causes an increase in the chemical interaction between E. coli and the films, which is an additional factor for the increasing bactericidal activity. From these results, DLC with TiO2 nanoparticles can be useful for producing coatings with antibacterial properties.

In vitro adhesion and anti-inflammatory properties of native Lactobacillus fermentum and Lactobacillus delbrueckii spp.

PubMed

Archer, A C; Kurrey, N K; Halami, P M

2018-03-14

This study aimed at characterizing the adhesion and immune-stimulatory properties of native probiotic Lactobacillus fermentum (MCC 2759 and MCC 2760) and Lactobacillus delbrueckii MCC 2775. Adhesion of the strains was assessed in Caco-2 and HT-29 cell lines. Expression of adhesion and immune markers were evaluated in Caco-2 cells by real-time qPCR. The cultures displayed >80% of adhesion to both cell lines and also induced the expression of mucin-binding protein (mub) gene in the presence of mucin, bile and pancreatin. Adhesion was mediated by carbohydrate and proteinaceous factors. The cultures stimulated the expression of inflammatory cytokines in Caco-2 cells. However, pro-inflammatory genes were down-regulated upon challenge with lipopolysaccharide and IL-10 was up-regulated by the cultures. Cell wall extract of L. fermentum MCC 2760 induced the expression of IL-6 by 5·47-fold, whereas crude culture filtrate enhanced the expression of IL-10 by 14·87-fold compared to LPS control. The bacterial cultures exhibited strong adhesion and anti-inflammatory properties. This is the first report to reveal the role of adhesion markers of L. fermentum and L. delbrueckii by qPCR. The strain-specific anti-inflammatory property of native cultures may be useful to alleviate inflammatory conditions and develop a target-based probiotic. © 2018 The Society for Applied Microbiology.

Tannins Possessing Bacteriostatic Effect Impair Pseudomonas aeruginosa Adhesion and Biofilm Formation

PubMed Central

Trentin, Danielle S.; Silva, Denise B.; Amaral, Matheus W.; Zimmer, Karine R.; Silva, Márcia V.; Lopes, Norberto P.; Giordani, Raquel B.; Macedo, Alexandre J.

2013-01-01

Plants produce many compounds that are biologically active, either as part of their normal program of growth and development or in response to pathogen attack or stress. Traditionally, Anadenanthera colubrina, Commiphora leptophloeos and Myracrodruon urundeuva have been used by communities in the Brazilian Caatinga to treat several infectious diseases. The ability to impair bacterial adhesion represents an ideal strategy to combat bacterial pathogenesis, because of its importance in the early stages of the infectious process; thus, the search for anti-adherent compounds in plants is a very promising alternative. This study investigated the ability of stem-bark extracts from these three species to control the growth and prevent biofilm formation of Pseudomonas aeruginosa, an important opportunistic pathogen that adheres to surfaces and forms protective biofilms. A kinetic study (0–72 h) demonstrated that the growth of extract-treated bacteria was inhibited up to 9 h after incubation, suggesting a bacteriostatic activity. Transmission electron microscopy and fluorescence microscopy showed both viable and nonviable cells, indicating bacterial membrane damage; crystal violet assay and scanning electron microscopy demonstrated that treatment strongly inhibited biofilm formation during 6 and 24 h and that matrix production remained impaired even after growth was restored, at 24 and 48 h of incubation. Herein, we propose that the identified (condensed and hydrolyzable) tannins are able to inhibit biofilm formation via bacteriostatic properties, damaging the bacterial membrane and hindering matrix production. Our findings demonstrate the importance of this abundant class of Natural Products in higher plants against one of the most challenging issues in the hospital setting: biofilm resilience. PMID:23776646

Oriented Adhesion of Escherichia coli to Polystyrene Particles

PubMed Central

Jones, Joseph F.; Feick, Jason D.; Imoudu, Daniel; Chukwumah, Nkiru; Vigeant, Margot; Velegol, Darrell

2003-01-01

The adhesion of nonflagellated Escherichia coli strain K-12 to polystyrene (PS) latex spheres or glass capillaries has been observed by using several techniques. Attention was focused on the orientation of the rod-shaped bacteria as they adhered to the surfaces in 100 mM phosphate-buffered saline. Data show that PS particles adhered to the ends of the bacteria more than 90% of the time. Moreover, the PS particles adhered to one end only, never to both. Similarly, for experiments with bacteria adhering to glass, the bacteria adhered on their ends. In order to determine whether the end of a bacterium had a different charge density from that of the middle, rotational electrophoresis experiments were used. These experiments indicated no measurable charge nonuniformity. In order to examine how strongly adhered the bacteria were to the PS particles, differential electrophoresis was used. Almost always, bacteria were found to be irreversibly adhered to the PS spheres. The cause of the oriented adhesion is not likely due to surface lipopolysaccharides (LPS), since the three strains of K-12 that were used, each having a different length of LPS, showed similar behavior. The results are discussed in terms of bacterial cell polarity. The data indicate that nanodomains on the bacterial ends are important for adhesion and that the time scale for irreversible adhesion is short. PMID:14602608

A simple and rapid method for optical visualization and quantification of bacteria on textiles

PubMed Central

Stiefel, Philipp; Schneider, Jana; Amberg, Caroline; Maniura-Weber, Katharina; Ren, Qun

2016-01-01

To prevent bacterial contamination on textiles and the associated undesired effects different biocidal coatings have been investigated and applied. However, due to health and environmental concerns anti-adhesive coatings preventing the binding of bacteria would be favored. To develop such anti-adhesive coatings simple assays for reliable and fast screening are beneficial. Here an easy-to-handle, robust and rapid assay to assess bacteria on textiles utilizing a tetrazolium salt was reported. The assay allowed direct eye visualization of the color change of the textiles containing bacteria, facilitating fast screening. Quantification of the adhered bacteria could be done by generating standard curves which correlate the staining intensity to cell numbers. An additional advantage of the described assay is that with the same detection method anti-adhesive and biocidal effects can be investigated. The method was applied to different coatings, using Pseudomonas aeruginosa and Staphylococcus aureus as model organisms. The detection limit was found to be between 2.5 * 106 and 9.4 * 108 for P. aeruginosa and between 1 * 106 and 3.3 * 108 for S. aureus. The anti-adhesive coating PLUMA was demonstrated to reduce bacterial adhesion without killing them, whereas the biocidal coating TH22-27 caused a clear reduction in the number of viable cells. PMID:28004762

Biofilm prevention by dicephalic cationic surfactants and their interactions with DNA.

PubMed

Piecuch, A; Lamch, Ł; Paluch, E; Obłąk, E; Wilk, K A

2016-09-01

The studies were aimed to contribute to the elucidation of the relationships between structure of the double-headed cationic surfactants-N,N-bis[3,3'-(dimethylamine)- propyl]alkylamide dihydrochlorides and N,N-bis[3,3'-(trimethylammonio)propyl]alkylamide dibromides (alkyl: n-C9 H19 , n-C11 H23 , n-C13 H27 , n-C15 H31 ) and their antibacterial and biofilm preventing activity. The minimal inhibitory and bactericidal concentrations (MIC and MBC) of dicephalic surfactants against Staphylococcus epidermidis and Pseudomonas aeruginosa were tested using standard methods. Pseudomonas aeruginosa was resistant to studied compounds but MBC values against Staph. epidermidis reached 0·48-0·01 mmol l(-1) . The influence of dicephalic surfactants on bacterial biofilm and adhesion to the various surfaces was investigated with crystal violet staining or colony counting. The reduction in bacterial adhesion was observed, especially in the case of glass and stainless steel. The condensation of the DNA was shown in the ethidium bromide intercalation assay. Dicephalic surfactants exhibited antibacterial activity against Staph. epidermidis. The activity of studied compounds depended on the hydrocarbon chain length and the counterion. Surfactants deposited on different materials reduced Staph. epidermidis adhesion, dependently on the surfactant structure and the substratum. Dicephalic surfactants showed the ability of DNA compaction. This study points the possibility of application of dicephalic surfactants as the surface-coating agents to prevent biofilm formation. These compounds efficiently condensed DNA and are potential candidates for further studies towards the transfection. © 2016 The Society for Applied Microbiology.

DEVELOPMENT OF A MODEL TO INVESTIGATE RED BLOOD CELL SURFACE CHARACTERISTICS AFTER CRYOPRESERVATION.

PubMed

Gordiyenko, O I; Anikieieva, M O; Rozanova, S L; Kovalenko, S Ye; Kovalenkol, I F; Gordiyenko, E O

2015-01-01

Maintaining cell surface properties after freezing and thawing, characterized in particular by the surface potential and associated with it cell ability to intercellular adhesion, could be used as a characteristic of successful cryopreservation. This study was conducted to research applying different erythrocytes freezing modes and analyses the regimes cryopreservation effect on the cell surface charge and adhesion to microorganisms. Human erythrocytes frozen by three modes. In order to determine adhesion index was used dried bacterial cells of S. thermophilus. The surface charge of erythrocytes was evaluated using Alcian blue cationic dye. The results showed the significant decrease in the lactobacillus adhesion to erythrocytes frozen glycerol and 1,2-propanediol. After erythrocytes were freezen with glycerol and 1,2-propanediol, the cationic dye binding to erythrocytes significantly reduced. AB binding to erythrocytes frozen with PEG-1500 does not differ from control data. Erythrocytes frozen with PEG-1500 mantained surface properties after thawing better, compared to erythrocytes cryopreserved by other methods.

Influenza viral neuraminidase primes bacterial coinfection through TGF-β-mediated expression of host cell receptors.

PubMed

Li, Ning; Ren, Aihui; Wang, Xiaoshuang; Fan, Xin; Zhao, Yong; Gao, George F; Cleary, Patrick; Wang, Beinan

2015-01-06

Influenza infection predisposes the host to secondary bacterial pneumonia, which is a major cause of mortality during influenza epidemics. The molecular mechanisms underlying the bacterial coinfection remain elusive. Neuraminidase (NA) of influenza A virus (IAV) enhances bacterial adherence and also activates TGF-β. Because TGF-β can up-regulate host adhesion molecules such as fibronectin and integrins for bacterial binding, we hypothesized that activated TGF-β during IAV infection contributes to secondary bacterial infection by up-regulating these host adhesion molecules. Flow cytometric analyses of a human lung epithelial cell line indicated that the expression of fibronectin and α5 integrin was up-regulated after IAV infection or treatment with recombinant NA and was reversed through the inhibition of TGF-β signaling. IAV-promoted adherence of group A Streptococcus (GAS) and other coinfective pathogens that require fibronectin for binding was prevented significantly by the inhibition of TGF-β. However, IAV did not promote the adherence of Lactococcus lactis unless this bacterium expressed the fibronectin-binding protein of GAS. Mouse experiments showed that IAV infection enhanced GAS colonization in the lungs of wild-type animals but not in the lungs of mice deficient in TGF-β signaling. Taken together, these results reveal a previously unrecognized mechanism: IAV NA enhances the expression of cellular adhesins through the activation of TGF-β, leading to increased bacterial loading in the lungs. Our results suggest that TGF-β and cellular adhesins may be potential pharmaceutical targets for the prevention of coinfection.

Wood adhesives prepared from lucerne fiber fermentation residues of Ruminococcus albus and Clostridium thermocellum

Treesearch

P. J. Weimer; R. G. Koegel; Linda F. Lorenz; Charles R. Frihart; William R. Kenealy

2005-01-01

Fermentation residues (consisting of incompletely fermented fiber, adherent bacterial cells, and a glycocalyx material that enhanced bacterial adherence) were obtained by growing the anaerobic cellulolytic bacteria Ruminococcus albus 7 or Clostridium thermocellum ATCC 27405 on a fibrous fraction derived from lucerne (Medicago sativa L.). The dried residue was able to...

Characterization of silver nanoparticle-infused tissue adhesive for ophthalmic use.

PubMed

Yee, William; Selvaduray, Guna; Hawkins, Benjamin

2015-03-01

In this work, we demonstrate the successful enhancement of breaking strength, adhesive strength, and antibacterial efficacy of ophthalmic tissue adhesive (2-octyl cyanoacrylate) by doping with silver nanoparticles, and investigate the effects of nanoparticle size and concentration. Recent work has shown that silver nanoparticles are a viable antibacterial additive to many compounds, but their efficacy in tissue adhesives was heretofore untested. Our results indicate that doping the adhesive with silver nanoparticles reduced bacterial growth by an order of magnitude or more; nanoparticle size and concentration had minimal influence in the range tested. Tensile breaking strength of polymerized adhesive samples and adhesive strength between a T-shaped support and excised porcine sclera were measured using a universal testing machine according to ASTM (formerly American Society for Testing and Materials) standard techniques. Both tests showed significant improvement with the addition of silver nanoparticles. The enhanced mechanical strength and antibacterial efficacy of the doped adhesive supports the use of tissue adhesives as a viable supplement or alternative to sutures. Copyright © 2015 Elsevier Ltd. All rights reserved.

An in vitro study on bacterial growth interactions and intestinal epithelial cell adhesion characteristics of probiotic combinations.

PubMed

Moussavi, Mahta; Adams, Michelle Catherine

2010-05-01

The aims of this study were to examine long-term growth interactions of five probiotic strains (Lactobacillus casei 01, Lactobacillus plantarum HA8, Lactobacillus rhamnosus GG, Lactobacillus reuteri ATCC 55730 and Bifidobacterium lactis Bb12) either alone or in combination with Propionibacterium jensenii 702 in a co-culture system and to determine their adhesion ability to human colon adenocarcinoma cell line Caco-2. Growth patterns of probiotic Lactobacillus strains were not considerably affected by the presence of P. jensenii 702, whereas lactobacilli exerted a strong antagonistic action against P. jensenii 702. In the co-culture of Bif. lactis Bb12 and P. jensenii 702, a significant synergistic influence on growth of both bacteria was observed (P < 0.05). The results of adhesion assay showed that when probiotic strains were tested in combination, there was evidence of an associated effect on percentage adherence. However, in most cases these differences were not statistically significant (P < 0.05). Adhesion percentage of Lb. casei 01 and Lb. rhamnosus GG both decreased significantly in the presence of P. jensenii 702 compared to their adhesion levels when alone (P < 0.05). These results show that the survival and percentage adhesion of some probiotic strains may be influenced by the presence of other strains and this should be considered when formulating in the probiotic products.

Grinding With Diamond Burs and Hydrothermal Aging of a Y-TZP Material: Effect on the Material Surface Characteristics and Bacterial Adhesion.

PubMed

Dutra, Dam; Pereira, Gkr; Kantorski, K Z; Exterkate, Ram; Kleverlaan, C J; Valandro, L F; Zanatta, F B

The aim of this study was to evaluate the effect of grinding with diamond burs and low-temperature aging on the material surface characteristics and bacteria adhesion on a yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) surface. Y-TZP specimens were made from presintered blocks, sintered as recommended by the manufacturer, and assigned into six groups according to two factors-grinding (three levels: as sintered, grinding with extra-fine diamond bur [25-μm grit], and grinding with coarse diamond bur [181-μm grit]) and hydrothermal aging-to promote low-temperature degradation (two levels: presence/absence). Phase transformation (X-ray diffractometer), surface roughness, micromorphological patterns (atomic force microscopy), and contact angle (goniometer) were analyzed. Bacterial adhesion (colony-forming units [CFU]/biofilm) was quantified using an in vitro polymicrobial biofilm model. Both the surface treatment and hydrothermal aging promoted an increase in m-phase content. Roughness values increased as a function of increasing bur grit sizes. Grinding with a coarse diamond bur resulted in significantly lower values of contact angle (p<0.05) when compared with the extra-fine and control groups, while there were no differences (p<0.05) after hydrothermal aging simulation. The CFU/biofilm results showed that neither the surface treatment nor hydrothermal aging simulation significantly affected the bacteria adherence (p>0.05). Grinding with diamond burs and hydrothermal aging modified the Y-TZP surface properties; however, these properties had no effect on the amount of bacteria adhesion on the material surface.

Optical tweezers for single molecule force spectroscopy on bacterial adhesion organelles

NASA Astrophysics Data System (ADS)

Andersson, Magnus; Axner, Ove; Uhlin, Bernt Eric; Fällman, Erik

2006-08-01

Instrumentation and methodologies for single molecule force spectroscopy on bacterial adhesion organelles by the use of force measuring optical tweezers have been developed. A thorough study of the biomechanical properties of fimbrial adhesion organelles expressed by uropathogenic E. coli, so-called pili, is presented. Steady-state as well as dynamic force measurements on P pili, expressed by E. coli causing pyelonephritis, have revealed, among other things, various unfolding and refolding properties of the helical structure of P pili, the PapA rod. Based on these properties an energy landscape model has been constructed by which specific biophysical properties of the PapA rod have been extracted, e.g. the number of subunits, the length of a single pilus, bond lengths and activation energies for bond opening and closure. Moreover, long time repetitive measurements have shown that the rod can be unfolded and refolded repetitive times without losing its intrinsic properties. These properties are believed to be of importance for the bacteria's ability to maintain close contact with host cells during initial infections. The results presented are considered to be of importance for the field of biopolymers in general and the development of new pharmaceuticals towards urinary tract infections in particular. The results show furthermore that the methodology can be used to gain knowledge of the intrinsic biomechanical function of adhesion organelles. The instrumentation is currently used for characterization of type 1 pili, expressed by E. coli causing cystitis, i.e. infections in the bladder. The first force spectrometry investigations of these pili will be presented.

Role of bacteria in leukocyte adhesion deficiency-associated periodontitis.

PubMed

Hajishengallis, George; Moutsopoulos, Niki M

2016-05-01

Leukocyte adhesion deficiency Type I (LAD-I)-associated periodontitis is an aggressive form of inflammatory bone loss that has been historically attributed to lack of neutrophil surveillance of the periodontal infection. However, this form of periodontitis has proven unresponsive to antibiotics and/or mechanical removal of the tooth-associated biofilm. Recent studies in LAD-I patients and relevant animal models have shown that the fundamental cause of LAD-I periodontitis involves dysregulation of a granulopoietic cytokine cascade. This cascade includes interleukin IL-23 (IL-23) and IL-17 that drive inflammatory bone loss in LAD-I patients and animal models and, moreover, foster a nutritionally favorable environment for bacterial growth and development of a compositionally unique microbiome. Although the lack of neutrophil surveillance in the periodontal pockets might be expected to lead to uncontrolled bacterial invasion of the underlying connective tissue, microbiological analyses of gingival biopsies from LAD-I patients did not reveal tissue-invasive infection. However, bacterial lipopolysaccharide was shown to translocate into the lesions of LAD-I periodontitis. It is concluded that the bacteria serve as initial triggers for local immunopathology through translocation of bacterial products into the underlying tissues where they unleash the dysregulated IL-23-IL-17 axis. Subsequently, the IL-23/IL-17 inflammatory response sustains and shapes a unique local microbiome which, in turn, can further exacerbate inflammation and bone loss in the susceptible host. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bacterial plaque retention on oral hard materials: effect of surface roughness, surface composition, and physisorbed polycarboxylate.

PubMed

McConnell, Marla D; Liu, Yu; Nowak, Andrew P; Pilch, Shira; Masters, James G; Composto, Russell J

2010-03-15

Bacterial adhesion to oral hard materials is dependent on various factors, for example, surface roughness and surface composition. In this study, bacteria retention on three oral hard substrates, hydroxyapatite (HAP), enamel, and polished enamel (p-enamel) were investigated. The surface morphology and roughness of the three substrates were measured by scanning probe microscopy. HAP had the roughest surface, followed by enamel and polished enamel. For each individual substrate type, the roughness was shown to increase with scan size up to 50 microm x 50 microm. For HAP and enamel, roughness decreased considerably after formation of a pellicle, while addition of polymer coating to the pellicle layer reduced roughness much less in comparison. Bacterial surface coverage was measured at 30 min, 3 h, and 24 h on both native and surface-modified substrates, which were coated with two different polycarboxylate-based polymers, Gantrez S97 and Carbopol 940. As a result, the polymer coated surfaces had reduced bacteria coverage compared with the native surfaces over all time points and substrates measured. The reduction is the combined effect of electrostatic repulsion and sequestering of Ca(2+) ions at the surface, which plays a key role in the initial adhesion of bacteria to enamel surfaces in models of plaque formation. (c) 2009 Wiley Periodicals, Inc.

Superiority of a functional leukocyte adhesiveness/aggregation test over the white blood cell count to discriminate between mild and significant inflammatory response in patients with acute bacterial infections.

PubMed

Rogowski, Ori; Rotstein, Rivka; Zeltzer, David; Misgav, Sarit; Justo, Daniel; Avitzour, Daniel; Mardi, Tamar; Serov, Jacob; Arber, Nadir; Berliner, Shlomo; Shapira, Itzhak

2002-01-01

Electronic cell counters may underestimate the white blood cell count (WBCC) in the presence of aggregated leukocytes. In the present study we focused on the possibility of using a functional, as opposed to an anatomic, count to circumvent this eventual underestimation. A model of bacterial infection was used because of the importance of leukocytosis in the physician's clinical decision-making process. There were 35 patients with low C-reactive protein (CRP) concentrations (0.5-4.9 mg/dL), 45 with intermediate (5-9.9 mg/dL), and 120 with relatively high (>10 mg/dL) CRP concentrations. A significant (P=0.008) difference was noted between the state of leukocyte adhesiveness/aggregation in the peripheral blood of individuals with low CRP concentrations (3.5%+/-4.3%) and those with high CRP concentrations (7.4%+/-8%), while there was no significant difference in the respective number of WBCs per cubic millimeter (cmm) (11,600 +/- 5,500 and 14,000 +/- 7,200, respectively). We raise the possibility that a functional test might be superior over an anatomic count in patients with acute bacterial infection and a significant acute phase response. Copyright 2002 Wiley-Liss, Inc.

Analysis of bacterial detachment from substratum surfaces by the passage of air-liquid interfaces.

PubMed

Gómez-Suárez, C; Busscher, H J; van der Mei, H C

2001-06-01

A theoretical analysis of the detachment of bacteria adhering to substratum surfaces upon the passage of an air-liquid interface is given, together with experimental results for bacterial detachment in the absence and presence of a conditioning film on different substratum surfaces. Bacteria (Streptococcus sobrinus HG1025, Streptococcus oralis J22, Actinomyces naeslundii T14V-J1, Bacteroides fragilis 793E, and Pseudomonas aeruginosa 974K) were first allowed to adhere to hydrophilic glass and hydrophobic dimethyldichlorosilane (DDS)-coated glass in a parallel-plate flow chamber until a density of 4 x 10(6) cells cm(-2) was reached. For S. sobrinus HG1025, S. oralis J22, and A. naeslundii T14V-J1, the conditioning film consisted of adsorbed salivary components, while for B. fragilis 793E and P. aeruginosa 974K, the film consisted of adsorbed human plasma components. Subsequently, air bubbles were passed through the flow chamber and the bacterial detachment percentages were measured. For some experimental conditions, like with P. aeruginosa 974K adhering to DDS-coated glass and an air bubble moving at high velocity (i.e., 13.6 mm s(-1)), no bacteria detached upon passage of an air-liquid interface, while for others, detachment percentages between 80 and 90% were observed. The detachment percentage increased when the velocity of the passing air bubble decreased, regardless of the bacterial strain and substratum surface hydrophobicity involved. However, the variation in percentages of detachment by a passing air bubble depended greatly upon the strain and substratum surface involved. At low air bubble velocities the hydrophobicity of the substratum had no influence on the detachment, but at high air bubble velocities all bacterial strains were more efficiently detached from hydrophilic glass substrata. Furthermore, the presence of a conditioning film could either inhibit or stimulate detachment. The shape of the bacterial cell played a major role in detachment at high air bubble velocities, and spherical strains (i.e., streptococci) detached more efficiently than rod-shaped organisms. The present results demonstrate that methodologies to study bacterial adhesion which include contact with a moving air-liquid interface (i.e., rinsing and dipping) yield detachment of an unpredictable number of adhering microorganisms. Hence, results of studies based on such methodologies should be referred as "bacterial retention" rather than "bacterial adhesion".

Evaluation of the anti-adhesive effect of milk fat globule membrane glycoproteins on Helicobacter pylori in the human NCI-N87 cell line and C57BL/6 mouse model.

PubMed

Horemans, Tessa; Kerstens, Monique; Clais, Sofie; Struijs, Karin; van den Abbeele, Pieter; Van Assche, Tim; Maes, Louis; Cos, Paul

2012-08-01

 The interest in non-antibiotic therapies for Helicobacter pylori infections in man has considerably grown because increasing numbers of antibiotic-resistant strains are being reported. Intervention at the stage of bacterial attachment to the gastric mucosa could be an approach to improve the control/eradication rate of this infection.  Fractions of purified milk fat globule membrane glycoproteins were tested in vitro for their cytotoxic and direct antibacterial effect. The anti-adhesive effect on H. pylori was determined first in a cell model using the mucus-producing gastric epithelial cell line NCI-N87 and next in the C57BL/6 mouse model after dosing at 400 mg/kg protein once or twice daily from day -2 to day 4 post-infection. Bacterial loads were determined by using quantitative real-time PCR and the standard plate count method.  The milk fat globule membrane fractions did not show in vitro cytotoxicity, and a marginal antibacterial effect was demonstrated for defatted milk fat globule membrane at 256 μg/mL. In the anti-adhesion assay, the results varied from 56.0 ± 5.3% inhibition for 0.3% crude milk fat globule membrane to 79.3 ± 3.5% for defatted milk fat globule membrane. Quite surprisingly, in vivo administration of the same milk fat globule membrane fractions did not confirm the anti-adhesive effects and even caused an increase in bacterial load in the stomach.  The promising anti-adhesion in vitro results could not be confirmed in the mouse model, even after the highest attainable exposure. It is concluded that raw or defatted milk fat globule membrane fractions do not have any prophylactic or therapeutic potential against Helicobacter infection. © 2012 Blackwell Publishing Ltd.

The Haemophilus influenzae Hap autotransporter mediates microcolony formation and adherence to epithelial cells and extracellular matrix via binding regions in the C-terminal end of the passenger domain.

PubMed

Fink, Doran L; Buscher, Amy Z; Green, Bruce; Fernsten, Phillip; St Geme, Joseph W

2003-03-01

The pathogenesis of non-typable Haemophilus influenzae disease begins with colonization of the nasopharynx and is facilitated by bacterial adherence to respiratory mucosa. The H. influenzae Hap autotransporter is a non-pilus adhesin that promotes adherence to epithelial cells and selected extracellular matrix proteins and mediates bacterial aggregation and microcolony formation. In addition, Hap has serine protease activity. Hap contains a 110 kDa internal passenger domain called HapS and a 45 kDa C-terminal translocator domain called Hapbeta. In the present study, we sought to define the structural basis for Hap adhesive activities. Based on experiments using a panel of monoclonal antibodies against HapS, a deletion derivative lacking most of HapS and a purified fragment of HapS, we established that adherence to epithelial cells is mediated by sequences within the C-terminal 311 residues of HapS. In additional experiments, we discovered that bacterial aggregation is also mediated by sequences within the C-terminal 311 residues of HapS and occurs via HapS-HapS interaction between molecules on neighbouring organisms. Finally, we found that adherence to fibronectin, laminin and collagen IV is mediated in part by sequences within the C-terminal 311 residues of HapS and in full by sequences within the C-terminal 511 residues of HapS. Taken together, these results demonstrate that all Hap adhesive activities reside in the C-terminal portion of HapS. Coupled with earlier observations, the current results establish that HapS adhesive activities and HapS protease activity are contained in separate modules of the protein.

Adhesion and Early Colonization of S. Mutans on Lithium Disilicate Reinforced Glass-Ceramics, Monolithic Zirconia and Dual Cure Resin Cement.

PubMed

Viitaniemi, L; Abdulmajeed, A; Sulaiman, T; Söderling, E; Närhi, T

2017-12-01

Monolithic zirconia and glass ceramics are increasingly used in implant crowns. Limited data is available on bacterial adhesion and early biofilm formation on these materials. Four different materials were investigated: (1) Lithium disilicate glass-ceramics (LDS), (2) Fully stabilized zirconia (FSZ), (3) Partially stabilized zirconia (PSZ), and (4) Dual curing cement (DCC). The materials' surfaces were characterized with spinning disc confocal microscopy and by water contact angle and surface free energy (SFE) measurements. For the adhesion tests the materials were rolled in suspensions of Streptococcus mutans. Early biofilm formation was studied on the materials and allowing the biofilms to form for 24 h. S. mutans cell counts were determined by plate culturing. ANOVA and post-hoc Tukey's tests (p⟨0.05) were used for statistical evaluation. The LDS surfaces were clearly hydrophilic with the highest SFE value (p⟨0.001). For S. mutans adhesion, the ranking of the materials from lowest to highest was: LDS = FSZ ⟨ DCC ⟨ PSZ (p⟨0.05). No significant differences among the materials were noticed in biofilm formation. LDS has lower S.mutans adhesion than other materials examined in this study, but the difference was not reflected in early biofilm formation. Copyright© 2017 Dennis Barber Ltd.

Anti-Adhesion Activity of A2-type Proanthocyanidins (a Cranberry Major Component) on Uropathogenic E. coli and P. mirabilis Strains

PubMed Central

Nicolosi, Daria; Tempera, Gianna; Genovese, Carlo; Furneri, Pio M.

2014-01-01

Urinary tract infections (UTIs) are relatively common in women and may be classified as uncomplicated or complicated, depending upon the urinary tract anatomy and physiology. Acute uncomplicated cystitis (AUC) occurs when urinary pathogens from the bowel or vagina colonize the periurethral mucosa and reach the bladder. The vast majority of episodes in healthy women involving the same bacterial strain that caused the initial infection are thought to be reinfections. About 90% of AUC are caused by uropathogenic Escherichia coli (UPEC), but Proteus mirabilis also plays an important role. Several studies support the importance of cranberry (Vaccinium macrocarpon) proanthocyanidins in preventing adhesion of P-fimbriated UPEC to uroepithelial cells. In this study, we evaluated the in vitro anti-adhesion activity of A2-linked proanthocyanidins from cranberry on a UPEC and Proteus mirabilis strains and their possible influence on urease activity of the latter. A significant reduction of UPEC adhesion (up to 75%) on the HT1376 cell line was observed vs. control. For the strains of P. mirabilis there was also a reduction of adhesion (up to 75%) compared to controls, as well as a reduction in motility and urease activity. These results suggest that A2-type cranberry proanthocyanidins could aid in maintaining urinary tract health. PMID:27025740

Adhesive Properties and Acid-Forming Activity of Lactobacilli and Streptococci Under Inhibitory Substances, Such as Nitrates.

PubMed

Hakobyan, L; Harutyunyan, K; Harutyunyan, N; Melik-Andreasyan, G; Trchounian, A

2016-06-01

One of the main requirements for probiotics is their ability to survive during passage through gastrointestinal tract and to maintain their activity at different adverse conditions. The aim of the study was to look for the strains of lactobacilli and streptococci with high adhesive properties even affected by inhibitory substances, such as nitrates (NO3 (-)). To study the adhesion properties hemagglutination reaction of bacterial cells with red blood cells of different animals and humans was used. The acid formation ability of bacteria was determined by the method of titration after 7 days of incubation in the sterile milk. These properties were investigated at different concentrations of NO3 (-). The high concentration (mostly ≥2.0 %) NO3 (-) inhibited the growth of both lactobacilli and streptococci, but compared with streptococcal cultures lactobacilli, especially Lactobacillus acidophilus Ep 317/402, have shown more stability and higher adhesive properties. In addition, the concentrations of NO3 (-) of 0.5-2.0 % decreased the acid-forming activity of the strains, but even under these conditions they coagulated milk and, in comparison to control, formed low acidity in milk. Thus, the L. acidophilus Ep 317/402 with high adhesive properties has demonstrated a higher activity of NO3 (-) transformation.

Statistical analysis of the Bacterial Carbohydrate Structure Data Base (BCSDB): Characteristics and diversity of bacterial carbohydrates in comparison with mammalian glycans

PubMed Central

Herget, Stephan; Toukach, Philip V; Ranzinger, René; Hull, William E; Knirel, Yuriy A; von der Lieth, Claus-Wilhelm

2008-01-01

Background There are considerable differences between bacterial and mammalian glycans. In contrast to most eukaryotic carbohydrates, bacterial glycans are often composed of repeating units with diverse functions ranging from structural reinforcement to adhesion, colonization and camouflage. Since bacterial glycans are typically displayed at the cell surface, they can interact with the environment and, therefore, have significant biomedical importance. Results The sequence characteristics of glycans (monosaccharide composition, modifications, and linkage patterns) for the higher bacterial taxonomic classes have been examined and compared with the data for mammals, with both similarities and unique features becoming evident. Compared to mammalian glycans, the bacterial glycans deposited in the current databases have a more than ten-fold greater diversity at the monosaccharide level, and the disaccharide pattern space is approximately nine times larger. Specific bacterial subclasses exhibit characteristic glycans which can be distinguished on the basis of distinctive structural features or sequence properties. Conclusion For the first time a systematic database analysis of the bacterial glycome has been performed. This study summarizes the current knowledge of bacterial glycan architecture and diversity and reveals putative targets for the rational design and development of therapeutic intervention strategies by comparing bacterial and mammalian glycans. PMID:18694500

Nanobiotechnology Perspectives on Prevention and Treatment of Ortho-paedic Implant Associated Infection.

PubMed

Borse, Vivek; Pawar, Vaishali; Shetty, Gautam; Mullaji, Arun; Srivastava, Rohit

2016-01-01

Implants are an inevitable part of orthopaedic surgery. However, implant associated infection remains a major challenge for orthopaedic surgeons and researchers. This review focuses on current options available for prevention of implant associated infection, their drawbacks and future promising applications of nanotechnology-based approaches. Nanobiotechnology has shown remarkable progress in recent years especially in biomaterials, diagnostics, and drug delivery system. Although several applications of nanobiotechnology in orthopaedics have been described, few have elaborated their role in the prevention of implant related infection in orthopaedics. Novel "smart" drug delivery systems that release antibiotics locally in response to stimuli such as pH, temperature, enzymes or antigens; implant surface modification on a nanoscale to inhibit bacterial adhesion and propagation at the surgical site and biological approaches such as gene therapy to neutralize bacterial virulence and biomolecules to inhibit the quorum sensing adhesion of bacteria and disruption of biofilms can be used effectively to prevent orthopaedic implant related bacterial infection.

Molecular response of Escherichia coli adhering onto nanoscale topography

NASA Astrophysics Data System (ADS)

Rizzello, Loris; Galeone, Antonio; Vecchio, Giuseppe; Brunetti, Virgilio; Sabella, Stefania; Pompa, Pier Paolo

2012-10-01

Bacterial adhesion onto abiotic surfaces is an important issue in biology and medicine since understanding the bases of such interaction represents a crucial aspect in the design of safe implant devices with intrinsic antibacterial characteristics. In this framework, we investigated the effects of nanostructured metal substrates on Escherichia coli adhesion and adaptation in order to understand the bio-molecular dynamics ruling the interactions at the interface. In particular, we show how highly controlled nanostructured gold substrates impact the bacterial behavior in terms of morphological changes and lead to modifications in the expression profile of several genes, which are crucially involved in the stress response and fimbrial synthesis. These results mainly demonstrate that E. coli cells are able to sense even slight changes in surface nanotopography and to actively respond by activating stress-related pathways. At the same time, our findings highlight the possibility of designing nanoengineered substrates able to trigger specific bio-molecular effects, thus opening the perspective of smartly tuning bacterial behavior by biomaterial design.

Variations in the Degree of d-Alanylation of Teichoic Acids in Lactococcus lactis Alter Resistance to Cationic Antimicrobials but Have No Effect on Bacterial Surface Hydrophobicity and Charge▿

PubMed Central

Giaouris, Efstathios; Briandet, Romain; Meyrand, Mickael; Courtin, Pascal; Chapot-Chartier, Marie-Pierre

2008-01-01

An increase of the degree of d-alanylation of teichoic acids in Lactococcus lactis resulted in a significant increase of bacterial resistance toward the cationic antimicrobials nisin and lysozyme, whereas the absence of d-alanylation led to a decreased resistance toward the same compounds. In contrast, the same variations of the d-alanylation degree did not modify bacterial cell surface charge and hydrophobicity. Bacterial adhesion to polystyrene and glass surfaces was not modified either. PMID:18539809

Phosphoproteomics in bacteria: towards a systemic understanding of bacterial phosphorylation networks.

PubMed

Jers, Carsten; Soufi, Boumediene; Grangeasse, Christophe; Deutscher, Josef; Mijakovic, Ivan

2008-08-01

Bacteria use protein phosphorylation to regulate all kinds of physiological processes. Protein phosphorylation plays a role in several key steps of the infection process of bacterial pathogens, such as adhesion to the host, triggering and regulation of pathogenic functions as well as biochemical warfare; scrambling the host signaling cascades and impairing its defense mechanisms. Recent phosphoproteomic studies indicate that the bacterial protein phosphorylation networks could be more complex than initially expected, comprising promiscuous kinases that regulate several distinct cellular functions by phosphorylating different protein substrates. Recent advances in protein labeling with stable isotopes in the field of quantitative mass spectrometry phosphoproteomics will enable us to chart the global phosphorylation networks and to understand the implication of protein phosphorylation in cellular regulation on the systems scale. For the study of bacterial pathogens, in particular, this research avenue will enable us to dissect phosphorylation-related events during different stages of infection and stimulate our efforts to find inhibitors for key kinases and phosphatases implicated therein.

The Role of Oligosaccharides in Host-Microbial Interactions for Human Health.

PubMed

Ross, Sarah A; Lane, Jonathan A; Marotta, Mariarosaria; Kavanaugh, Devon; Ryan, Joseph Thomas; Joshi, Lokesh; Hickey, Rita M

Milk oligosaccharides have many associated bioactivities which can contribute to human health and offer protective properties to the host. Such bioactivities include anti-infective properties whereby oligosaccharides interact with bacterial cells and prevent adhesion to the host and subsequent colonization. Milk oligosaccharides have also been shown to alter the glycosylation of intestinal cells, leading to a reduction in pathogenic colonization. In addition, these sugars promote adhesion of commensal bacterial strains to host cells as well as possessing the ability to alter mucin expression in intestinal cells and improve barrier function. The ability of milk oligosaccharides to alter the transcriptome of both commensal bacterial strains and intestinal epithelial cells has also been revealed, indicating the potential of many cell types to detect the presence of milk oligosaccharides and respond accordingly at the genetic level. Interestingly, domestic animal milk may provide a bioactive source of oligosaccharides for formula supplementation with the aim of emulating the gold standard that is human milk. Overall, this review highlights the ability of milk oligosaccharides to promote health in a variety of ways, for example, through direct bacterial interactions, immunomodulatory activities, promotion of gut barrier function, and induction of protective transcriptional responses.

[Urinary catheter biofilm infections].

PubMed

Holá, V; Růzicka, F

2008-04-01

Urinary tract infections, most of which are biofilm infections in catheterized patients, account for more than 40% of hospital infections. Bacterial colonization of the urinary tract and catheters causes not only infection but also other complications such as catheter blockage by bacterial encrustation, urolithiasis and pyelonephritis. About 50% of long-term catheterized patients face urinary flow obstruction due to catheter encrustation, but no measure is currently available to prevent it. Encrustation has been known either to result from metabolic dysfunction or to be of microbial origin, with urease positive bacterial species implicated most often. Infectious calculi account for about 15-20% of all cases of urolithiasis and are often associated with biofilm colonization of a long-term indwelling urinary catheter or urethral stent. The use of closed catheter systems is helpful in reducing such problems; nevertheless, such a system only delays the inevitable, with infections emerging a little later. Various coatings intended to prevent the bacterial adhesion to the surface of catheters and implants and thus also the emergence of biofilm infections, unfortunately, do not inhibit the microbial adhesion completely and permanently and the only reliable method for biofilm eradication remains the removal of the foreign body from the patient.

Influence of femtosecond laser produced nanostructures on biofilm growth on steel

NASA Astrophysics Data System (ADS)

Epperlein, Nadja; Menzel, Friederike; Schwibbert, Karin; Koter, Robert; Bonse, Jörn; Sameith, Janin; Krüger, Jörg; Toepel, Jörg

2017-10-01

Biofilm formation poses high risks in multiple industrial and medical settings. However, the robust nature of biofilms makes them also attractive for industrial applications where cell biocatalysts are increasingly in use. Since tailoring material properties that affect bacterial growth or its inhibition is gaining attention, here we focus on the effects of femtosecond laser produced nanostructures on bacterial adhesion. Large area periodic surface structures were generated on steel surfaces using 30-fs laser pulses at 790 nm wavelength. Two types of steel exhibiting a different corrosion resistance were used, i.e., a plain structural steel (corrodible) and a stainless steel (resistant to corrosion). Homogeneous fields of laser-induced periodic surface structures (LIPSS) were realized utilizing laser fluences close to the ablation threshold while scanning the sample under the focused laser beam in a multi-pulse regime. The nanostructures were characterized with optical and scanning electron microscopy. For each type of steel, more than ten identical samples were laser-processed. Subsequently, the samples were subjected to microbial adhesion tests. Bacteria of different shape and adhesion behavior (Escherichia coli and Staphylococcus aureus) were exposed to laser structures and to polished reference surfaces. Our results indicate that E. coli preferentially avoids adhesion to the LIPSS-covered areas, whereas S. aureus favors these areas for colonization.

Aggregatibacter actinomycetemcomitans regulates the expression of integrins and reduces cell adhesion via integrin α5 in human gingival epithelial cells.

PubMed

Kochi, Shinsuke; Yamashiro, Keisuke; Hongo, Shoichi; Yamamoto, Tadashi; Ugawa, Yuki; Shimoe, Masayuki; Kawamura, Mari; Hirata-Yoshihara, Chiaki; Ideguchi, Hidetaka; Maeda, Hiroshi; Takashiba, Shogo

2017-12-01

Gingival epithelial cells form a physiological barrier against bacterial invasion. Excessive bacterial invasion destroys the attachment between the tooth surface and the epithelium, resulting in periodontitis. Integrins play a significant role in cell attachment; therefore, we hypothesized that bacterial infection might decrease the expressions of these integrins in gingival epithelial cells, resulting in reduced cell adhesion. Immortalized human gingival epithelial cells were co-cultured with Aggregatibacter actinomycetemcomitans Y4 (Aa Y4), and the gene expression levels of IL-8, proliferating cell nuclear antigen (PCNA), and integrins (α2, α3, α5, β4, and β6) were measured using quantitative reverse transcription polymerase chain reaction. Expression of PCNA and integrins, except integrin α5, was significantly downregulated, while expression of IL-8 and integrin α5 was significantly upregulated in the cells co-cultured with Aa Y4. The number of adherent cells significantly decreased when co-cultured with Aa Y4, as determined using cell adhesion assays. In the cells co-cultured with Aa Y4 and an integrin α5 neutralizing antibody, there was no effect on the expression of IL-8 and PCNA, while the expressions of integrins α2, α3, β4, and β6, and the number of adherent cells did not decrease. The number of invading bacteria in the cells was reduced in the presence of the antibody and increased in the presence of TLR2/4 inhibitor. Therefore, integrin α5 might be involved in Aa Y4 invasion into gingival epithelial cells, and the resulting signal transduction cascade reduces cell adhesion by decreasing the expression of integrins, while the TLR2/4 signaling cascade regulates IL-8 expression.

Mycobacterium tuberculosis Pili promote adhesion to and invasion of THP-1 macrophages.

PubMed

Ramsugit, Saiyur; Pillay, Manormoney

2014-01-01

Central to the paradigm of the pathogenesis of Mycobacterium tuberculosis is its ability to attach to, enter, and subsequently survive in host macrophages. However, little is known regarding the bacterial adhesins and invasins involved in this interaction with host macrophages. Pili are cell-surface structures produced by certain bacteria and have been implicated in adhesion to and invasion of phagocytes in several species. M. tuberculosis pili (MTP) are encoded by the Rv3312A (mtp) gene. In the present study, we assessed the ability of a Δmtp mutant and an mtp-complemented clinical strain to adhere to and invade THP-1 macrophages in comparison with the parental strain by determining colony-forming units. Both adhesion to and invasion of macrophages, although not reaching significance, were markedly reduced by 42.16% (P = 0.107) and 69.02% (P = 0.052), respectively, in the pili-deficient Δmtp mutant as compared with the wild-type. The pili-overexpressing complemented strain showed significantly higher levels of THP-1 macrophage adhesion (P = 0.000) and invasion (P = 0.040) than the mutant. We, thus, identified a novel adhesin and invasin of M. tuberculosis involved in adhesion to and invasion of macrophages.

Motility and Adhesiveness in Human Neutrophils

PubMed Central

Smith, C. Wayne; Hollers, James C.; Patrick, Richard A.; Hassett, Clare

1979-01-01

Human peripheral blood neutrophils (PMN) obtained from healthy adults were examined in vitro with techniques adapted to assess the effects of chemotactic factors (CF) on cellular configuration and adhesiveness. The results were compared with those that use certain conventional techniques for assessing chemotaxis and chemokinesis. Exposure of PMN to N-formyl-l-methionyl-l-phenylalanine (f-Met-Phe), zymosan-activated serum, bacterial chemotactic factor, or a low molecular weight chemotactic factor from activated serum (C5a) in the absence of a gradient resulted in a change in cellular shape from a spherical to a polarized configuration in a high percentage of cells. This occurred rapidly in suspension, under conditions designed to exclude a role for cell adhesiveness, and was reversible upon removal of the CF. Restimulation of cells with the CF resulted in reappearance of the polarized configuration to the same extent as on initial stimulation with one exception: f-Met-Phe pretreated cells failed to respond to f-Met-Phe, though they responded fully to the other CF. Each CF caused a significant increase in PMN attachment to protein-coated glass. This enhanced adhesiveness was not reversible upon removal of the CF when the cells were treated under conditions shown to produce chemotactic deactivation. Cells treated under these conditions also exhibited significantly reduced motility on glass and in micropore filters in the absence of a gradient of CF. Bacterial chemotactic factor, even at high concentrations, failed to produce deactivation and did not cause a sustained enhancement of adhesiveness. Images PMID:372238

An in vitro investigation of bacteria-osteoblast competition on oxygen plasma-modified PEEK.

PubMed

Rochford, Edward T J; Subbiahdoss, Guruprakash; Moriarty, T Fintan; Poulsson, Alexandra H C; van der Mei, Henny C; Busscher, Henk J; Richards, R Geoff

2014-12-01

Polyetheretherketone (PEEK) films were oxygen plasma treated to increase surface free energy and characterized by X-ray photoelectron microscopy, atomic force microscopy, and water contact angles. A parallel plate flow chamber was used to measure Staphylococcus epidermidis, Staphylococcus aureus, and U-2 OS osteosarcomal cell-line adhesion to the PEEK films in separate monocultures. In addition, bacteria and U-2 OS cells were cocultured to model competition between osteoblasts and contaminating bacteria for the test surfaces. Plasma treatment of the surfaces increased surface oxygen content and decreased the hydrophobicity of the materials, but did not lead to a significant difference in bacterial or U-2 OS cell adhesion in the monocultures. In the S. epidermidis coculture experiments, the U-2 OS cells adhered in greater numbers on the treated surfaces compared to the untreated PEEK and spread to a similar extent. However, in the presence of S. aureus, cell death of the U-2 OS occurred within 10 h on all surfaces. The results of this study suggest that oxygen plasma treatment of PEEK may maintain the ability of osteoblast-like cells to adhere and spread, even in the presence of S. epidermidis contamination, without increasing the risk of preoperative bacterial adhesion. Therefore, oxygen plasma-treated PEEK remains a promising method to improve implant surface free energy for osseointegration. © 2014 Wiley Periodicals, Inc.

Antiadhesion activity of juniper (Juniperus communis L.) preparations against Campylobacter jejuni evaluated with PCR-based methods.

PubMed

Klančnik, Anja; Zorko, Špela; Toplak, Nataša; Kovač, Minka; Bucar, Franz; Jeršek, Barbara; Smole Možina, Sonja

2018-03-01

The food-borne pathogen Campylobacter jejuni can cause bacterial gastrointestinal infections. Biofilm formation amplifies the risk of human infection by improving survival and persistence of C. jejuni in food processing environments and its transmission through the food chain. We aimed to control C. jejuni using an alternative strategy of low doses of Juniperus communis fruit preparations to target bacterial adhesion properties in the first step of biofilm formation. First, we defined the anti-Campylobacter activity of a juniper fruit crude extract and its fractionated biflavonoids, flavone glycosides, and purified amentoflavone, of juniper fruit essential oil and of juniper fruit postdistillation waste material extract. For accurate quantification of adherent C. jejuni, we optimised digital Polymerase Chain Reaction (PCR) and quantitative real-time PCR for construction of standard curves and quantification. We show for the first time that juniper fruit formulations can effectively inhibit adhesion of C. jejuni to polystyrene. Furthermore, ≥94% of the antiadhesion activity of juniper fruit crude extract and juniper fruit essential oil remained under food-related conditions: modified culture medium with glucose, or a stainless steel surface, or mixed co-cultures of C. jejuni and Listeria monocytogenes. This study indicates that addition of juniper fruit formulations can control growth and adhesion of C. jejuni and thus limit food chain transmission of campylobacters. Copyright © 2017 John Wiley & Sons, Ltd.

Pyruvate dehydrogenase subunit β of Lactobacillus plantarum is a collagen adhesin involved in biofilm formation.

PubMed

Salzillo, Marzia; Vastano, Valeria; Capri, Ugo; Muscariello, Lidia; Marasco, Rosangela

2017-04-01

Multi-functional surface proteins have been observed in a variety of pathogenic bacteria, where they mediate host cell adhesion and invasion, as well as in commensal bacterial species, were they mediate positive interaction with the host. Among these proteins, some glycolytic enzymes, expressed on the bacterial cell surface, can bind human extracellular matrix components (ECM). A major target for them is collagen, an abundant glycoprotein of connective tissues. We have previously shown that the enolase EnoA1 of Lactobacillus plantarum, one of the most predominant species in the gut microbiota of healthy individuals, is involved in binding with collagen type I (CnI). In this study, we found that PDHB, a component of the pyruvate dehydrogenase complex, contributes to the L. plantarum LM3 adhesion to CnI. By a cellular adhesion assay to immobilized CnI, we show that LM3-B1 cells, carrying a null mutation in the pdhB gene, bind to CnI - coated surfaces less efficiently than wild-type cells. Moreover, we show that the PDHB-CnI interaction requires a native state for PDHB. We also analyzed the ability to develop biofilm in wild-type and mutant strains and we found that the lack of the PDHB on cell surface generates cells partially impaired in biofilm development. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An anti-bacterial approach to nanoscale roughening of biomimetic rice-like pattern PP by thermal annealing

NASA Astrophysics Data System (ADS)

Jafari Nodoushan, Emad; Ebrahimi, Nadereh Golshan; Ayazi, Masoumeh

2017-11-01

In this paper, we introduced thermal annealing treatment as an effective way of increasing the nanoscale roughness of a semi-crystalline polymer surface. Annealing treatment applied to a biomimetic microscale pattern of rice leaf to achieve a superhydrophobic surface with a hierarchical roughness. Resulted surfaces was characterized by XRD, AFM and FE-SEM instruments and showed an increase of roughness and cristallinity within both time and temperature of treatment. These two parameters also impact on measured static contact angle up to 158°. Bacterial attachment potency has an inverse relationship with the similarity of surface pattern dimensions and bacterial size and due to that, thermal annealing could be an effective way to create anti-bacterial surface beyond its effect on water repellency. Point in case, the anti-bacterial properties of produced water-repellence surfaces of PP were measured and counted colonies of both gram-negative (E. coli) and gram-positive (S. aureus) bacteria reduced with the nature of PP and hierarchical pattern on that. Anti-bacterial characterization of the resulted surface reveals a stunning reduction in adhesion of gram-positive bacteria to the surface. S. aureus reduction rates equaled to 95% and 66% when compared to control blank plate and smooth surface of PP. Moreover, it also could affect the other type of bacteria, gram-negative (E. coli). In the latter case, adhesion reduction rates calculated 66% and 53% when against to the same controls, respectively.

Evaluation of adhesive and anti-adhesive properties of Pseudomonas aeruginosa biofilms and their inhibition by herbal plants

PubMed Central

Zameer, Farhan; MS, Rukmangada; Chauhan, Jyoti Bala; Khanum, Shaukath Ara; Kumar, Pramod; Devi, Aishwarya Tripurasundari; MN, Nagendra Prasad; BL, Dhananjaya

2016-01-01

Background and Objectives: Adhesion and colonization are prerequisites for the establishment of bacterial pathogenesis. The biofilm development of Pseudomonas aeruginosa was assessed on adhesive surfaces like dialysis membrane, stainless steel, glass and polystyrene. Materials and Methods: Microtiter plate biofilm assay was performed to assess the effect of nutrient medium and growth parameters of P. aeruginosa. Further, its growth on adhesive surfaces namely hydrophilic (dialysis membrane) and hydrophobic (polystyrene plate, square glass and stainless steel coupon) was assessed. The exopolysaccharide (EPS) was quantified using ruthenium red microplate assay and microscopic analysis was used to observe P. aeruginosa biofilm architecture. The anti-biofilm activity of herbal extracts on mature P. aeruginosa was performed. Results: The formation of large scale biofilms on dialysis membrane for 72 h was proved to be the best surface. In microscopic studies, very few exopolysaccaride fibrils, indicating a rather loose matrix was observed at 48 h. Further, thick exopolysaccaride, indicated higher adhesive properties at 72 h which is evident from ruthenium red staining. Among the plant extract used, Justicia wynaadensis leaf and Aristolochia indica (Eswari) root extract showed significant reduction of anti-biofilm activity of 0.178 OD and 0.192 OD in inhibiting mature biofilms at 0.225 OD respectively, suggesting the possible use of these extracts as efficient anti-adhesive and biofilm-disrupting agents with potential applications in controlling biofilms on surfaces. Conclusion: Our study facilitates better understanding in the development of P. aeruginosa biofilms on different food processing and clinical surfaces ultimately taking care of food safety and hygiene. PMID:27307976

Probiotic yeast Saccharomyces boulardii (nom. nud.) modulates adhesive properties of Candida glabrata.

PubMed

Tomičić, Zorica; Zupan, Jure; Matos, Tadeja; Raspor, Peter

2016-11-01

Following the widespread use of immunosuppressive therapy together with broad-spectrum antimycotic therapy, the frequency of mucosal and systemic infections caused by the pathogenic yeast Candida glabrata has increased in the past decades. Due to the resistance of C. glabrata to existing azole drugs, it is very important to look for new strategies helping the treatment of such fungal diseases. In this study, we investigated the effect of the probiotic yeast Saccharomyces boulardii (nom. nud.) on C. glabrata adhesion at different temperatures, pH values, and in the presence of fluconazole, itraconazole and amphotericin B. We also studied the adhesion of C. glabrata co-culture with Candida krusei, Saccharomyces cerevisiae, two bacterial probiotics Lactobacillus rhamnosus and Lactobacillus casei The method used to assess adhesion was crystal violet staining. Our results showed that despite the nonadhesiveness of S. boulardii cells, this probiotic significantly affected the adherence ability of C. glabrata This effect was highly dependent on C. glabrata strain and was either antagonistic or synergistic. Regarding the extrinsic factors, temperature did not indicate any significant influence on this S. boulardii modulatory effect, while at high pH and at increased concentrations of antimycotics, S. boulardii did not manage to repress the adhesion of C. glabrata strains. The experiments of C. glabrata co-cultures with other species showed that the adhesiveness of two separate cultures could not be used to predict the adhesiveness of their co-culture. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cell Adhesion Modification of Streptococcus viridians in the Presence of Xylitol

NASA Astrophysics Data System (ADS)

Esmacher, Jason; Vidakovich, Blair; Giangrande, Michael; Hoffmann, Peter

2012-10-01

There is scientific documentation that those who chew gum sweetened by the sugar alcohol xylitol report a dramatically lower incident of both dental caries and otitis media compared to those who chew conventional gum sweetened by sucrose. An explanation contends that xylitol interferes with the ability of Streptococcus viridian (SV) to form biofilms which is a necessary precursor to the bacteria's ability to damage human tissues. We have used atomic force microscopy to study the cell wall/fimbria properties at the nanonewton level in both the presence and absence of xylitol. The first set of measurements used varying concentrations of xylitol incorporated within the incubation medium. The second used non-xylitol grown bacteria, the xylitol was added externally at various concentrations. Our study suggests that growing SV with xylitol reduces their ability to adhere together. Additionally, externally added xylitol showed grouping of cell adhesion to a relatively narrow nanonewton spread that is concentration dependent. Measurement of the adhesion properties of the bacterial cell wall have found that there is a dramatic increase in the cell wall's firmness which simultaneously accompanied a decrease in its ability to support adhesion, even at very low concentrations of xylitol.

Reduced bacterial growth and increased osteoblast proliferation on titanium with a nanophase TiO2 surface treatment.

PubMed

Bhardwaj, Garima; Webster, Thomas J

2017-01-01

The attachment and initial growth of bacteria on an implant surface dictates the progression of infection. Treatment often requires aggressive antibiotic use, which does not always work. To overcome the difficulties faced in systemic and local antibiotic delivery, scientists have forayed into using alternative techniques, which includes implant surface modifications that prevent initial bacterial adhesion, foreign body formation, and may offer a controlled inflammatory response. The current study focused on using electrophoretic deposition to treat titanium with a nanophase titanium dioxide surface texture to reduce bacterial adhesion and growth. Two distinct nanotopographies were analyzed, Ti-160, an antimicrobial surface designed to greatly reduce bacterial colonization, and Ti-120, an antimicrobial surface with a topography that upregulates osteoblast activity while reducing bacterial colonization; the number following Ti in the nomenclature represents the atomic force microscopy root-mean-square roughness value in nanometers. There was a 95.6% reduction in Staphylococcus aureus (gram-positive bacteria) for the Ti-160-treated surfaces compared to the untreated titanium alloy controls. There was a 90.2% reduction in Pseudomonas aeruginosa (gram-negative bacteria) on Ti-160-treated surfaces compared to controls. For ampicillin-resistant Escherichia coli , there was an 81.1% reduction on the Ti-160-treated surfaces compared to controls. Similarly for surfaces treated with Ti-120, there was an 86.8% reduction in S. aureus , an 82.1% reduction in P. aeruginosa , and a 48.6% reduction in ampicillin-resistant E. coli . The Ti-120 also displayed a 120.7% increase at day 3 and a 168.7% increase at day 5 of osteoblast proliferation over standard titanium alloy control surfaces. Compared to untreated surfaces, Ti-160-treated titanium surfaces demonstrated a statistically significant 1 log reduction in S. aureus and P. aeruginosa , whereas Ti-120 provided an additional increase in osteoblast proliferation for up to 5 days, criteria, which should be further studied for a wide range of orthopedic applications.

Induction of trap formation in nematode-trapping fungi by bacteria-released ammonia.

PubMed

Su, H N; Xu, Y Y; Wang, X; Zhang, K Q; Li, G H

2016-04-01

A total of 11 bacterial strains were assayed for bacteria-induced trap formation in the nematode-trapping fungus Arthrobotrys oligospora YMF1·01883 with two-compartmented Petri dish. These strains were identified on the basis of their 16S rRNA gene sequences. Volatile organic compounds (VOCs) of eight isolates were extracted using solid-phase micro-extraction (SPME) and their structures were identified based on gas chromatography-mass spectrometry (GC-MS). At the same time, all isolates were used for quantitative measurement of ammonia by the indophenol blue method. The effects of pure commercial compounds on inducement of trap formation in A. oligospora were tested. Taken together, results demonstrated that the predominant bacterial volatile compound inducing trap formation was ammonia. Meanwhile, ammonia also played a role in other nematode-trapping fungi, including Arthrobotrys guizhouensis YMF1·00014, producing adhesive nets; Dactylellina phymatopaga YMF1·01474, producing adhesive knobs; Dactylellina cionopaga YMF1·01472, producing adhesive columns and Drechslerella brochopaga YMF1·01829, producing constricting rings. © 2016 The Society for Applied Microbiology.

Novel amphiphilic poly(dimethylsiloxane) based polyurethane networks tethered with carboxybetaine and their combined antibacterial and anti-adhesive property

NASA Astrophysics Data System (ADS)

Jiang, Jingxian; Fu, Yuchen; Zhang, Qinghua; Zhan, Xiaoli; Chen, Fengqiu

2017-08-01

The traditional nonfouling materials are powerless against bacterial cells attachment, while the hydrophobic bactericidal surfaces always suffer from nonspecific protein adsorption and dead bacterial cells accumulation. Here, amphiphilic polyurethane (PU) networks modified with poly(dimethylsiloxane) (PDMS) and cationic carboxybetaine diol through simple crosslinking reaction were developed, which had an antibacterial efficiency of 97.7%. Thereafter, the hydrolysis of carboxybetaine ester into zwitterionic groups brought about anti-adhesive properties against bacteria and proteins. The surface chemical composition and wettability performance of the PU network surfaces were investigated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle analysis. The surface distribution of PDMS and zwitterionic segments produced an obvious amphiphilic heterogeneous surface, which was demonstrated by atomic force microscopy (AFM). Enzyme-linked immunosorbent assays (ELISA) were used to test the nonspecific protein adsorption behaviors. With the advantages of the transition from excellent bactericidal performance to anti-adhesion and the combination of fouling resistance and fouling release property, the designed PDMS-based amphiphilic PU network shows great application potential in biomedical devices and marine facilities.

Evaluation of adhesion forces of Staphylococcus aureus along the length of Candida albicans hyphae.

PubMed

Ovchinnikova, Ekaterina S; Krom, Bastiaan P; Busscher, Henk J; van der Mei, Henny C

2012-11-27

Candida albicans is a human fungal pathogen, able to cause both superficial and serious, systemic diseases and is able to switch from yeast cells to long, tube-like hyphae, depending on the prevailing environmental conditions. Both morphological forms of C. albicans are found in infected tissue, often in combination with Staphylococcus aureus. Although bacterial adhesion to the different morphologies of C. albicans has been amply studied, possible differences in staphylococcal adhesion forces along the length of C. albicans hyphae have never been determined. In this study, we aim to verify the hypothesis that the forces mediating S. aureus NCTC8325-4GFP adhesion to hyphae vary along the length of C. albicans SC5314 and MB1 hyphae, as compared with adhesion to yeast cells. C. albicans hyphae were virtually divided into a "tip" (the growing and therefore youngest part of the hyphae), a "middle" and a so-called "head" region (the yeast cell from which germination started). Adhesion forces between S. aureus NCTC8325-4GFP and the different regions of C. albicans SC5314 hyphae were measured using atomic force microscopy. Strong adhesion forces were found at the tip and middle regions of C. albicans hyphae (-4.1 nN and -4.0 nN, respectively), while much smaller adhesion forces were measured at the head region (-0.3 nN). Adhesion forces exerted by the head region were comparable with the forces arising from budding yeast cells (-0.5 nN). A similar regional dependence of the staphylococcal adhesion forces was found for the clinical isolate involved in this study, C. albicans MB1. This is the first time that differences in adhesion forces between S. aureus and different regions of C. albicans hyphae have been demonstrated on a quantitative basis, supporting the view that the head region is different from the remainder of the hyphae. Notably it can be concluded that the properties of the hyphal head region are similar to those of budding yeast cells. These novel findings provide new insights in the intricate interkingdom interaction between C. albicans and S. aureus.

Effects of amine fluoride on biofilm growth and salivary pellicles.

PubMed

van der Mei, H C; Engels, E; de Vries, J; Busscher, H J

2008-01-01

The amine fluoride (AmF) N'-octadecyl-trimethylene-diamine-N,N,N'-tris(2-ethanol)-dihydro-fluoride is a cationic antimicrobial which can have beneficial effects on plaque formation. Here, we determine changes in pellicle and bacterial cell surface properties of the strains Actinomyces naeslundii HM1, Streptococcus mutans NS, S.mutans ATCC 700610, S. sobrinus HG1025 and S. oralis HM1 upon adsorption of this AmF and accompanying effects on bacterial adhesion and biofilm growth. In vitro pellicles had a zeta potential of -12 mV that became less negative upon adsorption of AmF. The chemical functionalities in which carbon and oxygen were involved changed after AmF adsorption and AmF-treated pellicles had a greater surface roughness than untreated pellicles. Water contact angles in vitro decreased from 56 to 45 degrees upon AmF treatment, which corresponded with water contact angles (44 degrees ) measured intraorally on the front incisors of volunteers immediately after using an AmF-containing toothpaste. All bacterial strains were negatively charged and their isoelectric points (IEP) increased upon AmF adsorption. Minimal inhibitory concentrations were smallest for strains exhibiting the largest increase in IEP. Adhesion to salivary pellicles and biofilm growth of the mutans streptococcal strains were significantly reduced after AmF treatment, but not of A. naeslundii or S. oralis. However, regardless of the strain involved, biofilm viability decreased significantly after AmF treatment. The electrostatic interaction between cationic AmF and negatively charged bacterial cell surfaces is pivotal in establishing reduced biofilm formation by AmF through a combination of effects on initial adhesion and killing. The major effect of AmF treatment, however, was a reduction brought about in biofilm viability.

X-ray crystal structures of Staphylococcus aureus collagen adhesin and sortases

NASA Astrophysics Data System (ADS)

Zong, Yinong

For many gram-positive bacteria, adhesion to host tissues is the first critical step in developing an infection. The adhesion is mediated by a superfamily of bacterial surface proteins, called MSCRAMM (microbial surface components recognizing adhesive matrix molecules), which in most cases are covalently attached to the cell wall peptidoglycan. Collagen adhesin (CNA) from Staphylococcus aureus, one of the MSCRAMMs, is responsible for bacterial binding to collagen molecules. CNA and other MSCRAMMs are anchored to the cell wall by a transpeptidase, sortase. The knowledge about how bacterial surface proteins adhere to host molecules and how they are sorted onto the cell wall is crucial for the design of novel antibiotics against bacterial infections. The crystal structures of CNA31--344 (residue 31 to 334), a truncation of CNA's collagen binding region, and CNA31--344 in complex with a collagen peptide were determined. CNA31--344 contains two domains, and between them is a big hole formed by a loop connecting the two domains. In the structure of CNA31--344-collagen complex, the collagen peptide is locked in the hole formed by the two domains of CNA 31--344. We reason that the two domains of CNA31--344 are open in the physiological condition, and close up when binding to collagen. This binding mechanism may be common for other bacterial collagen adhesins. There are two known sortases in Staphylococcus aureus. Sortase A is responsible for anchoring most MSCRAMMs that have a LPXTG (X represents any amino acid) sorting motif and sortase B for a bacterial ion acquisition protein. The crystal structures of both sortases indicate that they share a common catalytic mechanism. Unlike typical cysteine transpeptidases, sortases may use a novel Cys-Arg catalytic dyad instead of a Cys-His pair. All other sortases found in gram-positive bacteria may have similar active site architecture and employ the same catalytic dyad because the critical residues are all conserved among them. The structures of sortases in complex with their substrates and inhibitors are also useful to explain their substrate specificity and catalytic kinetics.

Adhesion of Porphyromonas gingivalis and Tannerella forsythia to dentin and titanium with sandblasted and acid etched surface coated with serum and serum proteins - An in vitro study.

PubMed

Eick, Sigrun; Kindblom, Christian; Mizgalska, Danuta; Magdoń, Anna; Jurczyk, Karolina; Sculean, Anton; Stavropoulos, Andreas

2017-03-01

To evaluate the adhesion of selected bacterial strains incl. expression of important virulence factors at dentin and titanium SLA surfaces coated with layers of serum proteins. Dentin- and moderately rough SLA titanium-discs were coated overnight with human serum, or IgG, or human serum albumin (HSA). Thereafter, Porphyromonas gingivalis, Tannerella forsythia, or a six-species mixture were added for 4h and 24h. The number of adhered bacteria (colony forming units; CFU) was determined. Arg-gingipain activity of P. gingivalis and mRNA expressions of P. gingivalis and T. forsythia proteases and T. forsythia protease inhibitor were measured. Coating specimens never resulted in differences exceeding 1.1 log10 CFU, comparing to controls, irrespective the substrate. Counts of T. forsythia were statistically significantly higher at titanium than dentin, the difference was up to 3.7 log10 CFU after 24h (p=0.002). No statistically significant variation regarding adhesion of the mixed culture was detected between surfaces or among coatings. Arg-gingipain activity of P. gingivalis was associated with log10 CFU but not with the surface or the coating. Titanium negatively influenced mRNA expression of T. forsythia protease inhibitor at 24h (p=0.026 uncoated, p=0.009 with serum). The present findings indicate that: a) single bacterial species (T. forsythia) can adhere more readily to titanium SLA than to dentin, b) low expression of T. forsythia protease inhibitor may influence the virulence of the species on titanium SLA surfaces in comparison with teeth, and c) surface properties (e.g. material and/or protein layers) do not appear to significantly influence multi-species adhesion. Copyright © 2016 Elsevier Ltd. All rights reserved.

The study of adhesive forces between the type-3 fimbriae of Klebsiella pneumoniae and collagen-coated surfaces by using optical tweezers

NASA Astrophysics Data System (ADS)

Chan, Chiahan; Fan, Chia-chieh; Huang, Ying-Jung; Peng, Hwei-Ling; Long, Hsu

2004-10-01

Adherence to host cells by a bacterial pathogen is a critical step for establishment of infection. It will contribute greatly to the understanding of bacterial pathogenesis by studying the biological force between a single pair of pathogen and host cell. In our experiment, we use a calibrated optical tweezers system to detach a single Klebsiella pneumoniae, the pathogen, from collagen, the host. By gradually increasing the laser power of the optical tweezers until the Klebsiella pneumoniae is detached from the collagen, we obtain the magnitude of the adhesive force between them. This happens when the adhesive force is barely equal to the trapping force provided by the optical tweezers at that specific laser power. This study is important because Klebsiella pneumoniae is an opportunistic pathogen which causes suppurative lesions, urinary and respiratory tract infections. It has been proved that type 3 fimbrial adhesin (mrkD) is strongly associated with the adherence of Klebsiella pneumoniae. Besides, four polymorphic mrkD alleles: namely, mrkDv1, v2, v3, and v4, are typed by using RFLP. In order to investigate the relationship between the structure and the function for each of these variants, DNA fragments encoding the major fimbrial proteins mrkA, mrkB, mrkC are expressed together with any of the four mrkD adhesins in E. coli JM109. Our study shows that the E. coli strain carrying the mrkDv3 fimbriae has the strongest binding activity. This suggests that mrkDv3 is a key factor that enhances the adherence of Klebsiella Pneumoniae to human body.

Bacterial flagellin—a potent immunomodulatory agent

PubMed Central

Hajam, Irshad A; Dar, Pervaiz A; Shahnawaz, Imam; Jaume, Juan Carlos; Lee, John Hwa

2017-01-01

Flagellin is a subunit protein of the flagellum, a whip-like appendage that enables bacterial motility. Traditionally, flagellin was viewed as a virulence factor that contributes to the adhesion and invasion of host cells, but now it has emerged as a potent immune activator, shaping both the innate and adaptive arms of immunity during microbial infections. In this review, we summarize our understanding of bacterial flagellin and host immune system interactions and the role flagellin as an adjuvant, anti-tumor and radioprotective agent, and we address important areas of future research interests. PMID:28860663

Synergistic effect of polyaniline coverage and surface microstructure on the inhibition of Pseudomonas aeruginosa biofilm formation.

PubMed

Gallarato, L A; Mulko, L E; Dardanelli, M S; Barbero, C A; Acevedo, D F; Yslas, E I

2017-02-01

Biofilm Formation is a survival strategy for microorganisms to adapt to their environment. Microbial cells in biofilm become tolerant and resistant to antibiotics and immune responses, increasing the difficulties for the clinical treatment of microbial infections. The surface chemistry and the micro/nano-topography of solid interfaces play a major role in mediating microorganism activity and adhesion. The effect of the surface chemical composition and topography on the adhesion and viability of Pseudomonas aeruginosa was studied. Polymeric (polyethylene terephthalate) surfaces were covered with a conducting polymer (polyaniline, PANI) film by in-situ polymerization and microstructured by Direct Laser Interference Patterning (DLIP). The viability of Pseudomonas aeruginosa on the different surfaces was investigated. The physicochemical properties of the surfaces were characterized by water contact angle measurements, scanning electron microscopy and atomic force microscopy. Bacterial biofilms were imaged by atomic force and scanning electron microscopies. The bacterial viability decreased on PANI compared with the substrate (polyethylene terephthalate) and it decreased even more upon micro-structuring the PANI films. In addition, the biofilm reduction could be improved using polymers with different chemical composition and/or the same polymer with different topographies. Both methods presented diminish the bacterial attachment and biofilm formation. These findings present a high impact related to materials for biomedical engineer applications regarding medical devices, as prostheses or catheters. Copyright © 2016 Elsevier B.V. All rights reserved.

Displacement of Enterococcus faecalis from hydrophobic and hydrophilic substrata by Lactobacillus and Streptococcus spp. as studied in a parallel plate flow chamber.

PubMed Central

Millsap, K; Reid, G; van der Mei, H C; Busscher, H J

1994-01-01

The displacement of Enterococcus faecalis 1131 from hydrophobic and hydrophilic substrata by isolates of Lactobacillus casei 36 and Streptococcus hyointestinalis KM1 was studied in a parallel plate flow chamber. The experiments were conducted with either 10 mM potassium phosphate buffer or human urine as the suspending fluid, and adhesion and displacement were measured by real-time in situ image analysis. The results showed that E. faecalis 1131 was displaced by lactobacilli (31%) and streptococci (74%) from fluorinated ethylene propylene in buffer and that displacement by lactobacilli was even more effective on a glass substratum in urine (54%). The passage of an air-liquid interface significantly impacted on adhesion, especially when the surface had been challenged with lactobacilli (up to 100% displacement) or streptococci (up to 94% displacement). These results showed that the parallel plate flow system with real-time in situ image analysis was effective for studying bacterial adhesion and that uropathogenic enterococci can be displaced by indigenous bacteria. Images PMID:8031082

Bifidobacteria isolated from infants and cultured on human milk oligosaccharides affect intestinal epithelial function

PubMed Central

Chichlowski, Maciej; De Lartigue, Guillaume; German, J. Bruce; Raybould, Helen E.; Mills, David A.

2012-01-01

Objectives Human milk oligosaccharides (HMO) are the third most abundant component of breast milk. Our laboratory has previously revealed gene clusters specifically linked to HMO metabolism in select bifidobacteria isolated from fecal samples of infants. Our objective was to test the hypothesis that growth of select bifidobacteria on HMO stimulates the intestinal epithelium. Methods Caco-2 and HT-29 cells were incubated with lactose (LAC) or HMO-grown Bifidobacterium longum subsp. infantis (B. infantis) or B. bifidum. Bacterial adhesion and translocation was measured by real-time quantitative PCR. Expression of pro- and anti-inflammatory cytokines and tight junction proteins was analyzed by real time reverse transcriptase. Distribution of tight junction proteins was measured using immunofluorescent microscopy. Results We showed that HMO-grown B. infantis had significantly higher rate of adhesion to HT-29 cells compared to B. bifidum. B. infantis also induced expression of a cell membrane glycoprotein, P-selectin glycoprotein ligand -1. Both B. infantis and B. bifidum grown on HMO caused less occludin relocalization and higher expression of anti-inflammatory cytokine, interleukin (IL)-10 compared to LAC-grown bacteria in Caco-2 cells. B. bifidum grown on HMO showed higher expression of junctional adhesion molecule and occludin in Caco-2 cell and HT-29 cells. There were no significant differences between LAC or HMO treatments in bacterial translocation. Conclusions This study provides evidence for the specific relationship between HMO-grown bifidobacteria and intestinal epithelial cells. To our knowledge, this is the first study describing HMO-induced changes in the bifidobacteria-intestinal cells interaction. PMID:22383026

Levorotatory carbohydrates and xylitol subdue Streptococcus mutans and Candida albicans adhesion and biofilm formation.

PubMed

Brambilla, Eugenio; Ionescu, Andrei C; Cazzaniga, Gloria; Ottobelli, Marco; Samaranayake, Lakshman P

2016-05-01

Dietary carbohydrates and polyols affect the microbial colonization of oral surfaces by modulating adhesion and biofilm formation. The aim of this study was to evaluate the influence of a select group of l-carbohydrates and polyols on either Streptococcus mutans or Candida albicans adhesion and biofilm formation in vitro. S. mutans or C. albicans suspensions were inoculated on polystyrene substrata in the presence of Tryptic soy broth containing 5% of the following compounds: d-glucose, d-mannose, l-glucose, l-mannose, d- and l-glucose (raceme), d- and l-mannose (raceme), l-glucose and l-mannose, sorbitol, mannitol, and xylitol. Microbial adhesion (2 h) and biofilm formation (24 h) were evaluated using MTT-test and Scanning Electron Microscopy (SEM). Xylitol and l-carbohydrates induced the lowest adhesion and biofilm formation in both the tested species, while sorbitol and mannitol did not promote C. albicans biofilm formation. Higher adhesion and biofilm formation was noted in both organisms in the presence of d-carbohydrates relative to their l-carbohydrate counterparts. These results elucidate, hitherto undescribed, interactions of the individually tested strains with l- and d-carbohydrates, and how they impact fungal and bacterial colonization. In translational terms, our data raise the possibility of using l-form of carbohydrates and xylitol for dietary control of oral plaque biofilms. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Bacterial biofilm as a cause of urinary tract infection--pathogens, methods of prevention and eradication].

PubMed

Ostrowska, Kinga; Strzelczyk, Aleksandra; Różalski, Antoni; Stączek, Paweł

2013-10-25

Urinary tract infections (UTI) are one of the common chronic and recurrent bacterial infections. Uropathogens which are able to form biofilm constitute a major etiological factor in UTI, especially among elder patients who are subject to long-term catheterization. It is caused by the capacity of the microorganisms for efficient and permanent colonization of tissues and also adhesion to diverse polymers used for urological catheter production such as propylene, polystyrene, silicone, polyvinyl chloride or silicone coated latex. Antibiotic therapy is the most common treatment for UTI. Fluoroquinolones, nitrofurans, beta-lactams, aminoglycosides, trimethoprim and sulfonamides are used predominantly. However, the biofilm due to its complex structure constitutes an effective barrier to the antibiotics used in the treatment of urinary tract infections. In addition, the growing number of multidrug resistant strains limits the usage of many of the currently available chemotherapeutic agents. Therefore, it seems important to search for new methods of treatment such as coating of catheters with non-pathogenic E. coli strains, the design of vaccines against fimbrial adhesive proteins of the bacterial cells or the use of bacteriophages.

E. coli interactions, adhesion and transport in alumino-silica clays.

PubMed

Wei, Houzhen; Yang, Guang; Wang, Boya; Li, Runwei; Chen, Gang; Li, Zhenze

2017-06-01

Bacterial adhesion and transport in the geological formation are controlled by their mutual complex interactions, which have been quantified by the traditional and extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory as well as direct atomic force microscopy (AFM) measurements. In this research, the DLVO forces calculated based on the independently determined bacterial and porous media surface thermodynamic properties were compared with those of AFM measurements. Although differences in the order of several magnitudes existed, forces obtained from both ways could explain the observations of E. coli attachment to alumino-silica clays evaluated in laboratory columns under saturated and steady-state flow conditions. E. coli deposition in alumino-silica clays was simulated using a two-site convection-dispersion transport model against E. coli transport breakthrough curves, which was then linked to the interactions forces. By exploring the differences of the two force measurements, it was concluded that the thermodynamic calculations could complement the direct force measurements in describing bacterial interactions with the surrounding environment and the subsequent transport in the porous media. Published by Elsevier B.V.

The bacterial adhesion on and the cytotoxicity of various dental cements used for implant-supported fixed restorations.

PubMed

Winkler, Cornelia; Schäfer, Lina; Felthaus, Oliver; Allerdings, Juri; Hahnel, Sebastian; Behr, Michael; Bürgers, Ralf

2014-05-01

Bacterial adhesion on and cytotoxicity of eight luting agents used for implant-supported restorations were investigated. Surface roughness (Ra), surface free energy (SFE) values and three-dimensional images by atomic-force microscopy of circular specimens were determined. Bacterial suspensions of Streptococcus sanguinis and Streptococcus epidermidis were incubated at 37°C for 2 h. Adhering bacteria were examined with fluorescence dye CytoX-Violet, stained with 4',6-diamidino-2-phenylindole (DAPI) and visualized by fluorescence-microscopy. Cytotoxicity-testing was done with WST-1-tests (water soluble tetrazolium). No significant differences, neither with regard to Ra nor regarding SFE were determined. Adherence of S. sanguinis was less on titanium, TempBondNE and TempBond. TempBond, TempBondNE, RelyX Unicem and Implantlink Semi Classic presented low amounts of S. epidermidis. WST-testing showed high cytotoxic potential of Harvard, Aqualox, TempBondNE and TempBond. No combination of low adherent bacteria with low cytotoxicity was found. From a biological in-vitro perspective, none of the cements may be recommended for implant-supported restorations.

In vitro performance of Ag-incorporated hydroxyapatite and its adhesive porous coatings deposited by electrostatic spraying.

PubMed

Gokcekaya, Ozkan; Webster, Thomas J; Ueda, Kyosuke; Narushima, Takayuki; Ergun, Celaletdin

2017-08-01

Bacterial infection of implanted materials is a significant complication that might require additional surgical operations for implant retrieval. As an antibacterial biomaterial, Ag-containing hydroxyapatite (HA) may be a solution to reduce the incidences of implant associated infections. In this study, pure, 0.2mol% and 0.3mol% Ag incorporated HA powders were synthesized via a precipitation method. Colloidal precursor dispersions prepared from these powders were used to deposit porous coatings onto titanium and stainless steel substrates via electrostatic spraying. The porous coating layers obtained with various deposition times and heat treatment conditions were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Scratch tests were conducted to assess the adhesion strength of the coating. Antibacterial activity of Ag-incorporated HA was tested towards Escherichia coli (E. coli) at various incubation times. Osteoblast adhesion on Ag-incorporated HA was evaluated to assess biocompatibility. Improvement in adhesion strength of the coating layer was observed after the heat treatment process due to mutual ionic diffusion at the interface. The Ag-incorporated HA killed all viable E. coli after 24h of incubation, whereas no antibacterial activity was detected with pure HA. In addition, in vitro cell culture tests demonstrated osteoblast adhesion similar to pure HA, which indicated good cytocompatibility. In summary, results of this study provided significant promise for the future study of Ag-incorporated HA for numerous medical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

In vitro characterization of multivalent adhesion molecule 7-based inhibition of multidrug-resistant bacteria isolated from wounded military personnel.

PubMed

Krachler, Anne Marie; Mende, Katrin; Murray, Clinton; Orth, Kim

2012-07-01

Treatment of wounded military personnel at military medical centers is often complicated by colonization and infection of wounds with pathogenic bacteria. These include nosocomially transmitted, often multidrug-resistant pathogens such as Acinetobacter baumannii-calcoaceticus complex, Pseudomonas aeruginosa and extended spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae. We analyzed the efficacy of multivalent adhesion molecule (MAM) 7-based anti-adhesion treatment of host cells against aforementioned pathogens in a tissue culture infection model. Herein, we observed that a correlation between two important hallmarks of virulence, attachment and cytotoxicity, could serve as a useful predictor for the success of MAM7-based inhibition against bacterial infections. Initially, we characterized 20 patient isolates (five from each pathogen mentioned above) in terms of genotypic diversity, antimicrobial susceptibility and important hallmarks of pathogenicity (biofilm formation, attachment to and cytotoxicity toward cultured host cells). All isolates displayed a high degree of genotypic diversity, which was also reflected by large strain-to-strain variability in terms of biofilm formation, attachment and cytotoxicity within each group of pathogen. Using non-pathogenic bacteria expressing MAM7 or latex beads coated with recombinant MAM7 for anti-adhesion treatment, we showed a decrease in cytotoxicity, indicating that MAM7 has potential as a prophylactic agent to attenuate infection by multidrug-resistant bacterial pathogens.

In vitro characterization of multivalent adhesion molecule 7-based inhibition of multidrug-resistant bacteria isolated from wounded military personnel

PubMed Central

Krachler, Anne Marie; Mende, Katrin; Murray, Clinton; Orth, Kim

2012-01-01

Treatment of wounded military personnel at military medical centers is often complicated by colonization and infection of wounds with pathogenic bacteria. These include nosocomially transmitted, often multidrug-resistant pathogens such as Acinetobacter baumannii-calcoaceticus complex, Pseudomonas aeruginosa and extended spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae. We analyzed the efficacy of multivalent adhesion molecule (MAM) 7-based anti-adhesion treatment of host cells against aforementioned pathogens in a tissue culture infection model. Herein, we observed that a correlation between two important hallmarks of virulence, attachment and cytotoxicity, could serve as a useful predictor for the success of MAM7-based inhibition against bacterial infections. Initially, we characterized 20 patient isolates (five from each pathogen mentioned above) in terms of genotypic diversity, antimicrobial susceptibility and important hallmarks of pathogenicity (biofilm formation, attachment to and cytotoxicity toward cultured host cells). All isolates displayed a high degree of genotypic diversity, which was also reflected by large strain-to-strain variability in terms of biofilm formation, attachment and cytotoxicity within each group of pathogen. Using non-pathogenic bacteria expressing MAM7 or latex beads coated with recombinant MAM7 for anti-adhesion treatment, we showed a decrease in cytotoxicity, indicating that MAM7 has potential as a prophylactic agent to attenuate infection by multidrug-resistant bacterial pathogens. PMID:22722243

The Anti-Biofouling Properties of Superhydrophobic Surfaces are Short-Lived.

PubMed

Hwang, Gi Byoung; Page, Kristopher; Patir, Adnan; Nair, Sean P; Allan, Elaine; Parkin, Ivan P

2018-06-12

Superhydrophobic surfaces are present in nature on the leaves of many plant species. Water rolls on these surfaces, and the rolling motion picks up particles including bacteria and viruses. Man-made superhydrophobic surfaces have been made in an effort to reduce biofouling. We show here that the anti-biofouling property of a superhydrophobic surface is due to an entrapped air-bubble layer that reduces contact between the bacteria and the surface. Further, we showed that prolonged immersion of superhydrophobic surfaces in water led to loss of the bubble-layer and subsequent bacterial adhesion that unexpectedly exceeded that of the control materials. This behavior was not restricted to one particular type of material but was evident on different types of superhydrophobic surfaces. This work is important in that it suggests that superhydrophobic surfaces may actually encourage bacterial adhesion during longer term exposure.

Antifouling activities of marine bacteria associated with sponge ( Sigmadocia sp.)

NASA Astrophysics Data System (ADS)

Satheesh, S.; Soniamby, A. R.; Sunjaiy Shankar, C. V.; Mary Josephine Punitha, S.

2012-09-01

The present study aimed at assessing the antifouling activity of bacteria associated with marine sponges. A total of eight bacterial strains were isolated from the surface of sponge Sigmadocia sp., of them, SS02, SS05 and SS06 showed inhibitory activity against biofilm-forming bacteria. The extracts of these 3 strains considerably affected the extracellular polymeric substance producing ability and adhesion of biofilm-forming bacterial strains. In addition to disc diffusion assay, microalgal settlement assay was carried out with the extracts mixed with polyurethane wood polish and coated onto stainless steel coupons. The extract of strain SS05 showed strong microalgal settlement inhibitory activity. Strain SS05 was identified as Bacillus cereus based on its 16S rRNA gene. Metabolites of the bacterial strains associated with marine invertebrates promise to be developed into environment-friendly antifouling agents.

Influence of nanophase titania topography on bacterial attachment and metabolism

PubMed Central

Park, Margaret R; Banks, Michelle K; Applegate, Bruce; Webster, Thomas J

2008-01-01

Surfaces with nanophase compared to conventional (or nanometer smooth) topographies are known to have different properties of area, charge, and reactivity. Previously published research indicates that the attachment of certain bacteria (such as Pseudomonas fluorescens 5RL) is higher on surfaces with nanophase compared to conventional topographies, however, their effect on bacterial metabolism is unclear. Results presented here show that the adhesion of Pseudomonas fluorescens 5RL and Pseudomonas putida TVA8 was higher on nanophase than conventional titania. Importantly, in terms of metabolism, bacteria attached to the nanophase surfaces had higher bioluminescence rates than on the conventional surfaces under all nutrient conditions. Thus, the results from this study show greater select bacterial metabolism on nanometer than conventional topographies, critical results with strong consequences for the design of improved biosensors for bacteria detection. PMID:19337418

Bacterial resistance of self-assembled surfaces using PPOm-b-PSBMAn zwitterionic copolymer - concomitant effects of surface topography and surface chemistry on attachment of live bacteria.

PubMed

Hsiao, Sheng-Wen; Venault, Antoine; Yang, Hui-Shan; Chang, Yung

2014-06-01

Three well-defined diblock copolymers made of poly(sulfobetaine methacrylate) (poly(SBMA)) and poly(propylene oxide) (PPO) groups were synthesized by atom transfer radical polymerization (ATRP) method. They were physically adsorbed onto three types of surfaces having different topography, including smooth flat surface, convex surface, and indented surface. Chemical state of surfaces was characterized by XPS while the various topographies were examined by SEM and AFM. Hydrophilicity of surfaces was dependent on both the surface chemistry and the surface topography, suggesting that orientation of copolymer brushes can be tuned in the design of surfaces aimed at resisting bacterial attachment. Escherichia coli, Staphylococcus epidermidis, Streptococcus mutans and Escherichia coli with green fluorescent protein (E. coli GFP) were used in bacterial tests to assess the resistance to bacterial attachment of poly(SBMA)-covered surfaces. Results highlighted a drastic improvement of resistance to bacterial adhesion with the increasing of poly(SBMA) to PPO ratio, as well as an important effect of surface topography. The chemical effect was directly related to the length of the hydrophilic moieties. When longer, more water could be entrapped, leading to improved anti-bacterial properties. The physical effect impacted on the orientation of the copolymer brushes, as well as on the surface contact area available. Convex surfaces as well as indented surfaces wafer presented the best resistance to bacterial adhesion. Indeed, bacterial attachment was more importantly reduced on these surfaces compared with smooth surfaces. It was explained by the non-orthogonal orientation of copolymer brushes, resulting in a more efficient surface coverage of zwitterionic molecules. This work suggests that not only the control of surface chemistry is essential in the preparation of surfaces resisting bacterial attachment, but also the control of surface topography and orientation of antifouling moieties. Copyright © 2014 Elsevier B.V. All rights reserved.

Unraveling bacterial networks and their antimicrobial susceptibility on silicon microarchitectures using intrinsic phase-shift spectroscopy

NASA Astrophysics Data System (ADS)

Leonard, Heidi; Holtzman, Liran; Haimov, Yuri; Weizman, Daniel; Kashi, Yechezkel; Nativ, Ofer; Halachmi, Sarel; Segal, Ester

2018-02-01

We have developed a rapid phenotypic antimicrobial susceptibility testing (AST) in which photonic 2D silicon microarrays are employed as both the optical transducer element and as a preferable solid-liquid interface for bacterial colonization. We harness the intrinsic ability of the micro-architectures to relay optical phase-shift reflectometric interference spectroscopic measurements (termed PRISM) and incorporate it into a platform for culture-free, label-free tracking of bacterial accumulation, proliferation, and death. This assay employs microfluidic channels interfaced with PRISM chips and is carried out in a two-stage process, namely bacteria seeding and antibiotic incubation. Bacteria proliferation within the microtopologies results in an increase in refractive index of the medium, yielding an increase in optical path difference, while cell death or bacteriostatic activity results in decreasing or unchanged values. The optical responses of bacteria to various concentrations of relevant antibiotics have been tracked in real time, allowing for accurate determination of the minimum inhibitory concentration (MIC) values within 2-3 hours. We further extended this work to analyze antibiotic susceptibilities of clinical isolates and direct urine samples derived from patients at neighboring hospitals in newly designed, disposable microfluidic devices. This has opened the door to the observation of unique bacterial behaviors, as we can evaluate bacterial adhesion, growth, and antibiotic resistance on different microarchitectures, different surface chemistries, and even different strains. Motility, charge, and biofilm abilities have been explored for their effect of bacterial adhesion to the microstructures as we further develop our method of rapid, label-free AST for full clinical application.

Adhesive/Dentin Interface: The Weak Link in the Composite Restoration

PubMed Central

Spencer, Paulette; Ye, Qiang; Park, Jonggu; Topp, Elizabeth M.; Misra, Anil; Marangos, Orestes; Wang, Yong; Bohaty, Brenda S.; Singh, Viraj; Sene, Fabio; Eslick, John; Camarda, Kyle; Katz, J. Lawrence

2010-01-01

Results from clinical studies suggest that more than half of the 166 million dental restorations that were placed in the United States in 2005 were replacements for failed restorations. This emphasis on replacement therapy is expected to grow as dentists use composite as opposed to dental amalgam to restore moderate to large posterior lesions. Composite restorations have higher failure rates, more recurrent caries, and increased frequency of replacement as compared to amalgam. Penetration of bacterial enzymes, oral fluids, and bacteria into the crevices between the tooth and composite undermines the restoration and leads to recurrent decay and premature failure. Under in vivo conditions the bond formed at the adhesive/dentin interface can be the first defense against these noxious, damaging substances. The intent of this article is to review structural aspects of the clinical substrate that impact bond formation at the adhesive/dentin interface; to examine physico-chemical factors that affect the integrity and durability of the adhesive/dentin interfacial bond; and to explore how these factors act synergistically with mechanical forces to undermine the composite restoration. The article will examine the various avenues that have been pursued to address these problems and it will explore how alterations in material chemistry could address the detrimental impact of physico-chemical stresses on the bond formed at the adhesive/dentin interface. PMID:20195761

Inhibition of Cronobacter sakazakii Adhesion to Caco-2 Cells by Commercial Dairy Powders and Raw Buttermilk.

PubMed

Ripollés, Daniel; Harouna, Saidou; Parrón, José A; Arenales, Irene; Calvo, Miguel; Pérez, María D; Sánchez, Lourdes

2017-02-08

Cronobacter sakazakii is a foodborne pathogen that has been associated with severe infections, mainly in neonates. The binding of this bacterium to host cell surfaces represents the first step in the pathogenesis of disease. An ELISA-based assay has been developed using a polyclonal antiserum against C. sakazakii to determine its adhesion to Caco-2 cells. The antiserum used recognized many of the outer membrane proteins of C. sakazakii. A positive correlation was found between the absorbance values obtained by ELISA and the number of bacteria adhered to cells determined by plate counting. The inhibitory effect on bacterial adhesion to cells observed with some dairy products was concentration-dependent. Commercial buttermilk caused the maximal reduction of the adhesion percentage (33.0 ± 5.07) at the highest concentration assayed (20 mg/mL), followed by butter serum (31.9 ± 5.36), skim milk (30.4 ± 5.07), and raw buttermilk (25.6 ± 3.80). In some cases, significant differences (p < 0.05) were found in the inhibition exerted by the different products evaluated. The results obtained in this study demonstrate that dairy products contain some components with the ability to inhibit the adhesion of C. sakazakii to Caco-2 cells.

Effect of oral cranberry extract (standardized proanthocyanidin-A) in patients with recurrent UTI by pathogenic E. coli: a randomized placebo-controlled clinical research study.

PubMed

Singh, Iqbal; Gautam, Lokesh Kumar; Kaur, Iqbal R

2016-09-01

To evaluate the effect of cranberry extract (PAC-A ~ proanthocyanidin-A) on the in vitro bacterial properties of uropathogenic (E. coli) and its efficacy/tolerability in patients with subclinical or uncomplicated recurrent UTI (r-UTI). After obtaining clearance from the ethics committee and administering a written informed consent, 72 patients with r-UTI were enrolled as per protocol (November 2011 to March 2013) in this prospective study, to randomly receive (PAC-A: group I, 36) or (placebo: group II, 36), for 12 weeks. Any change/reduction in the incidence of r-UTI at 12 weeks was construed to be the primary endpoint of this study. After 12 weeks, bacterial adhesion scoring decreased (0.28)/(2.14) in group I/II (p < 0.001); 32/36 (88.8 %) and 2/36 (5.5 %) in groups I and II, respectively, turned MRHA negative (p < 0.001); biofilm (p < 0.01) and bacterial growth (p < 0.001) decreased in group I; microscopic pyuria score was 0.36/2.0 in group I/II (p < 0.001); r-UTI decreased to 33.33 versus 88.89 % in group I/II (p < 0.001); mean subjective dysuria score was 0.19 versus 1.47 in group I/II (p < 0.001), while mean urine pH was 5.88 versus 6.30 in group I/II (p < 0.001). No in vitro antibacterial activity of cranberry could be demonstrated, and no adverse events were noted. The overall efficacy and tolerability of standardized cranberry extract containing (PAC-A) as a food supplement were superior to placebo in terms of reduced bacterial adhesion; bacterial MRHA negativity; urine pH reduction; and in preventing r-UTI (dysuria, bacteriuria and pyuria). Larger randomized controlled trials are needed to elucidate the precise role, exact dose and optimal duration of PAC-A therapy in patients at risk of r-UTI.

Influence of Silver-hydroxyapatite Nanocomposite Coating on Biofilm Formation of Joint Prosthesis and Its Mechanism.

PubMed

Zhao, L; Ashraf, M A

2015-12-01

The main reason for biomaterial related refractory infections is biofilm formation caused by bacterial adhesion on the surface of materials. Silver-hydroxyapatite (Ag/HA) nanocomposite coating can inhibit the formation of biofilm, but its mechanism is not clear. In order to clarify the mechanism, the amounts of biofilm on the Ag/HA composite coating and HA coating were determined, the release rates of silver nanoparticles in simulated body fluid (SBF) were detected by atomic absorption spectrometry, and the expression values of atlE , fbe , sap , iapB genes of Staphylococcus aureus were studied when they grew on Ag/HA composite coating and HA coating. The amount of the biofilm on the Ag/HA composite coating was significantly less than that on the HA coating, and the bacterial adhesion was decreased. The silver nanoparticles were released continuously in SBF and the release rate decreased gradually with time. The expression values of atlE , fbe and sap were high in the initial stage of adhesion and the expression value of iapB was high in the colonies-gathering stage in the control group, but they were all significantly inhibited in the presence of Ag. These results indicated that the main antibacterial effect of Ag/HA composite coating was achieved by the release of silver nanoparticles. The addition of Ag inhibited the expression of genes related to biofilm formation, which in turn inhibited the formation of biofilms. This provided theoretical support for the clinical application of Ag/HA composite coating.

Prevotella intermedia Induces Severe Bacteremic Pneumococcal Pneumonia in Mice with Upregulated Platelet-Activating Factor Receptor Expression

PubMed Central

Nagaoka, Kentaro; Morinaga, Yoshitomo; Nakamura, Shigeki; Harada, Tatsuhiko; Hasegawa, Hiroo; Izumikawa, Koichi; Ishimatsu, Yuji; Kakeya, Hiroshi; Nishimura, Masaharu; Kohno, Shigeru

2014-01-01

Streptococcus pneumoniae is the leading cause of respiratory infection worldwide. Although oral hygiene has been considered a risk factor for developing pneumonia, the relationship between oral bacteria and pneumococcal infection is unknown. In this study, we examined the synergic effects of Prevotella intermedia, a major periodontopathic bacterium, on pneumococcal pneumonia. The synergic effects of the supernatant of P. intermedia (PiSup) on pneumococcal pneumonia were investigated in mice, and the stimulation of pneumococcal adhesion to human alveolar (A549) cells by PiSup was assessed. The effects of PiSup on platelet-activating factor receptor (PAFR) transcript levels in vitro and in vivo were analyzed by quantitative real-time PCR, and the differences between the effects of pneumococcal infection induced by various periodontopathic bacterial species were verified in mice. Mice inoculated with S. pneumoniae plus PiSup exhibited a significantly lower survival rate, higher bacterial loads in the lungs, spleen, and blood, and higher inflammatory cytokine levels in the bronchoalveolar lavage fluid (macrophage inflammatory protein 2 and tumor necrosis factor alpha) than those infected without PiSup. In A549 cells, PiSup increased pneumococcal adhesion and PAFR transcript levels. PiSup also increased lung PAFR transcript levels in mice. Similar effects were not observed in the supernatants of Porphyromonas gingivalis or Fusobacterium nucleatum. Thus, P. intermedia has the potential to induce severe bacteremic pneumococcal pneumonia with enhanced pneumococcal adhesion to lower airway cells. PMID:24478074

Prevotella intermedia induces severe bacteremic pneumococcal pneumonia in mice with upregulated platelet-activating factor receptor expression.

PubMed

Nagaoka, Kentaro; Yanagihara, Katsunori; Morinaga, Yoshitomo; Nakamura, Shigeki; Harada, Tatsuhiko; Hasegawa, Hiroo; Izumikawa, Koichi; Ishimatsu, Yuji; Kakeya, Hiroshi; Nishimura, Masaharu; Kohno, Shigeru

2014-02-01

Streptococcus pneumoniae is the leading cause of respiratory infection worldwide. Although oral hygiene has been considered a risk factor for developing pneumonia, the relationship between oral bacteria and pneumococcal infection is unknown. In this study, we examined the synergic effects of Prevotella intermedia, a major periodontopathic bacterium, on pneumococcal pneumonia. The synergic effects of the supernatant of P. intermedia (PiSup) on pneumococcal pneumonia were investigated in mice, and the stimulation of pneumococcal adhesion to human alveolar (A549) cells by PiSup was assessed. The effects of PiSup on platelet-activating factor receptor (PAFR) transcript levels in vitro and in vivo were analyzed by quantitative real-time PCR, and the differences between the effects of pneumococcal infection induced by various periodontopathic bacterial species were verified in mice. Mice inoculated with S. pneumoniae plus PiSup exhibited a significantly lower survival rate, higher bacterial loads in the lungs, spleen, and blood, and higher inflammatory cytokine levels in the bronchoalveolar lavage fluid (macrophage inflammatory protein 2 and tumor necrosis factor alpha) than those infected without PiSup. In A549 cells, PiSup increased pneumococcal adhesion and PAFR transcript levels. PiSup also increased lung PAFR transcript levels in mice. Similar effects were not observed in the supernatants of Porphyromonas gingivalis or Fusobacterium nucleatum. Thus, P. intermedia has the potential to induce severe bacteremic pneumococcal pneumonia with enhanced pneumococcal adhesion to lower airway cells.

Influence of nanoscale topology on bactericidal efficiency of black silicon surfaces

NASA Astrophysics Data System (ADS)

Linklater, Denver P.; Khuong Duy Nguyen, Huu; Bhadra, Chris M.; Juodkazis, Saulius; Ivanova, Elena P.

2017-06-01

The nanostructuring of materials to create bactericidal and antibiofouling surfaces presents an exciting alternative to common methods of preventing bacterial adhesion. The fabrication of synthetic bactericidal surfaces has been inspired by the anti-wetting and anti-biofouling properties of insect wings, and other topologies found in nature. Black silicon is one such synthetic surfaces which has established bactericidal properties. In this study we show that time-dependent plasma etching of silicon wafers using 15, 30, and 45 min etching intervals, is able to produce different surface geometries with linearly increasing heights of approximately 280, 430, and 610 nm, respectively. After incubation on these surfaces with Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa bacterial cells it was established that smaller, more densely packed pillars exhibited the greatest bactericidal activity with 85% and 89% inactivation of bacterial cells, respectively. The decrease in the pillar heights, pillar cap diameter and inter-pillar spacing corresponded to a subsequent decrease in the number of attached cells for both bacterial species.

Nutritionally Variant Streptococci Interfere with Streptococcus mutans Adhesion Properties and Biofilm Formation.

PubMed

Angius, Fabrizio; Madeddu, Maria Antonietta; Pompei, Raffaello

2015-04-01

The bacterial species Streptococcus mutans is known as the main cause of dental caries in humans. Therefore, much effort has focused on preventing oral colonization by this strain or clearing it from oral tissues. The oral cavity is colonized by several bacterial species that constitute the commensal oral flora, but none of these is able to interfere with the cariogenic properties of S. mutans. This paper describes the interfering ability of some nutritionally variant streptococcal strains (NVS) with S. mutans adhesion to glass surfaces and also to hydroxylapatite. In mixed cultures, NVS induce a complete inhibition of S. mutans microcolony formation on cover glass slides. NVS can also block the adherence of radiolabeled S. mutans to hydroxylapatite in the presence of both saliva and sucrose. The analysis of the action mechanism of NVS demonstrated that NVS are more hydrophobic than S. mutans and adhere tightly to hard surfaces. In addition, a cell-free culture filtrate of NVS was also able to interfere with S. mutans adhesion to hydroxylapatite. Since NVS are known to secrete some important bacteriolytic enzymes, we conclude that NVS can be a natural antagonist to the cariogenic properties of S. mutans.

Adhesion to the host cell surface is sufficient to mediate Listeria monocytogenes entry into epithelial cells

PubMed Central

Ortega, Fabian E.; Rengarajan, Michelle; Chavez, Natalie; Radhakrishnan, Prathima; Gloerich, Martijn; Bianchini, Julie; Siemers, Kathleen; Luckett, William S.; Lauer, Peter; Nelson, W. James; Theriot, Julie A.

2017-01-01

The intestinal epithelium is the first physiological barrier breached by the Gram-positive facultative pathogen Listeria monocytogenes during an in vivo infection. Listeria monocytogenes binds to the epithelial host cell receptor E-cadherin, which mediates a physical link between the bacterium and filamentous actin (F-actin). However, the importance of anchoring the bacterium to F-actin through E-cadherin for bacterial invasion has not been tested directly in epithelial cells. Here we demonstrate that depleting αE-catenin, which indirectly links E-cadherin to F-actin, did not decrease L. monocytogenes invasion of epithelial cells in tissue culture. Instead, invasion increased due to increased bacterial adhesion to epithelial monolayers with compromised cell–cell junctions. Furthermore, expression of a mutant E-cadherin lacking the intracellular domain was sufficient for efficient L. monocytogenes invasion of epithelial cells. Importantly, direct biotin-mediated binding of bacteria to surface lipids in the plasma membrane of host epithelial cells was sufficient for uptake. Our results indicate that the only requirement for L. monocytogenes invasion of epithelial cells is adhesion to the host cell surface, and that E-cadherin–mediated coupling of the bacterium to F-actin is not required. PMID:28877987

Bacterial Coaggregation and Cohesion Among Isolates From Contact Lens Cases.

PubMed

Datta, Ananya; Stapleton, Fiona; Willcox, Mark D P

2018-06-01

The aim of this study was to examine cohesion, coaggregation, and coculture between bacteria commonly isolated from contact lens cases. Staphylococcus epidermidis, Staphylococcus haemolyticus, Micrococcus luteus, and Acinetobacter radioresistens (two strains each) isolated from contact lens cases of two asymptomatic wearers were used in this study. In the cohesion assay, bacteria were grown, washed, and examined by incubating lens cases with two different types of bacteria sequentially and assessing the number of adhered cells of each isolate. The ability of isolates to interfere with the growth of other isolates was tested by growing strains in cocultures for 24 hours and determining the numbers of cells of individual strains. For coaggregation, equal proportions of two bacterial suspensions were mixed and allowed to coaggregate for 24 hours. Inhibition of coaggregation was tested by the addition of lactose (0.06 M) or sucrose (0.06 M) or pronase. The initial adhesion of M. luteus or A. radioresistens significantly (P < 0.05) enhanced the subsequent adhesion of the staphylococci. The addition of A. radioresistens in liquid media significantly (P < 0.05) enhanced the growth of staphylococci. S. epidermidis or S. haemolyticus coaggregated with M. luteus or A. radioresistens. The degree of coaggregation varied between 30% and 54%. The highest coaggregation (54% ± 5%) was seen between A. radioresistens 22-1 and S. epidermidis 22-1, isolated from the same lens case. Only lactose or sucrose treatment of staphylococci could partly inhibit coaggregation of some pairs. Coaggregation, cohesion, and growth promotion may facilitate the process of bacterial colonization of contact lens cases.

The absence of N-acetylglucosamine in wall teichoic acids of Listeria monocytogenes modifies biofilm architecture and tolerance to rinsing and cleaning procedures

PubMed Central

Faille, Christine; Sadovskaya, Irina; Charbit, Alain; Benezech, Thierry; Shen, Yang; Loessner, Martin J.; Bautista, Jean Romain; Midelet-Bourdin, Graziella

2018-01-01

The wall teichoic acid (WTA) is the major carbohydrate found within the extracellular matrix of the Listeria monocytogenes biofilm. We first addressed the frequency of spontaneous mutations in two genes (lmo2549 and lmo2550) responsible for the GlcNAcylation in 93 serotype 1/2a strains that were mainly isolated from seafood industries. We studied the impact of mutations in lmo2549 or lmo2550 genes on biofilm formation by using one mutant carrying a natural mutation inactivating the lmo2550 gene (DSS 1130 BFA2 strain) and two EGD-e mutants that lack respective genes by in-frame deletion of lmo2549 or lmo2550 using splicing-by-overlap-extension PCR, followed by allelic exchange mutagenesis. The lmo2550 gene mutation, occurring in around 50% isolates, caused a decrease in bacterial adhesion to stainless steel compared to wild-type EGD-e strain during the adhesion step. On the other hand, bacterial population weren’t significantly different after 24h-biofilm formation. The biofilm architecture was different between the wild-type strain and the two mutants inactivated for lmo2549 or lmo2550 genes respectively with the presence of bacterial micro-colonies for mutants which were not observed in the wild-type EGD-e strain biofilm. These differences might account for the stronger hydrophilic surface exhibited by the mutant cells. Upon a water flow or to a cleaning procedure at a shear stress of 0.16 Pa, the mutant biofilms showed the higher detachment rate compared to wild-type strain. Meanwhile, an increase in the amount of residual viable but non-culturable population on stainless steel was recorded in two mutants. Our data suggests that the GlcNAc residue of WTA played a role in adhesion and biofilm formation of Listeria monocyctogenes. PMID:29320565

The absence of N-acetylglucosamine in wall teichoic acids of Listeria monocytogenes modifies biofilm architecture and tolerance to rinsing and cleaning procedures.

PubMed

Brauge, Thomas; Faille, Christine; Sadovskaya, Irina; Charbit, Alain; Benezech, Thierry; Shen, Yang; Loessner, Martin J; Bautista, Jean Romain; Midelet-Bourdin, Graziella

2018-01-01

The wall teichoic acid (WTA) is the major carbohydrate found within the extracellular matrix of the Listeria monocytogenes biofilm. We first addressed the frequency of spontaneous mutations in two genes (lmo2549 and lmo2550) responsible for the GlcNAcylation in 93 serotype 1/2a strains that were mainly isolated from seafood industries. We studied the impact of mutations in lmo2549 or lmo2550 genes on biofilm formation by using one mutant carrying a natural mutation inactivating the lmo2550 gene (DSS 1130 BFA2 strain) and two EGD-e mutants that lack respective genes by in-frame deletion of lmo2549 or lmo2550 using splicing-by-overlap-extension PCR, followed by allelic exchange mutagenesis. The lmo2550 gene mutation, occurring in around 50% isolates, caused a decrease in bacterial adhesion to stainless steel compared to wild-type EGD-e strain during the adhesion step. On the other hand, bacterial population weren't significantly different after 24h-biofilm formation. The biofilm architecture was different between the wild-type strain and the two mutants inactivated for lmo2549 or lmo2550 genes respectively with the presence of bacterial micro-colonies for mutants which were not observed in the wild-type EGD-e strain biofilm. These differences might account for the stronger hydrophilic surface exhibited by the mutant cells. Upon a water flow or to a cleaning procedure at a shear stress of 0.16 Pa, the mutant biofilms showed the higher detachment rate compared to wild-type strain. Meanwhile, an increase in the amount of residual viable but non-culturable population on stainless steel was recorded in two mutants. Our data suggests that the GlcNAc residue of WTA played a role in adhesion and biofilm formation of Listeria monocyctogenes.

Microcoupon Assay Of Adhesion And Growth Of Bacterial Films

NASA Technical Reports Server (NTRS)

Pierson, Duane L.; Koenig, David W.

1994-01-01

Microbiological assay technique facilitates determination of some characteristics of sessile bacteria like those that attach to and coat interior walls of water-purification systems. Biofilms cause sickness and interfere with purification process. Technique enables direct measurement of rate of attachment of bacterial cells, their metabolism, and effects of chemicals on them. Used to quantify effects of both bactericides and growth-stimulating agents and in place of older standard plate-count and tube-dilution techniques.

Washing-resistant surfactant coated surface is able to inhibit pathogenic bacteria adhesion

NASA Astrophysics Data System (ADS)

Treter, Janine; Bonatto, Fernando; Krug, Cristiano; Soares, Gabriel Vieira; Baumvol, Israel Jacob Rabin; Macedo, Alexandre José

2014-06-01

Surface-active substances, which are able to organize themselves spontaneously on surfaces, triggering changes in the nature of the solid-liquid interface, are likely to influence microorganism adhesion and biofilm formation. Therefore, this study aimed to evaluate chemical non-ionic surfactants activity against pathogenic microbial biofilms and to cover biomaterial surfaces in order to obtain an anti-infective surface. After testing 11 different surfactants, Pluronic F127 was selected for further studies due to its non-biocidal properties and capability to inhibit up to 90% of biofilm formation of Gram-positive pathogen and its clinical isolates. The coating technique using direct impregnation on the surface showed important antibiofilm formation characteristics, even after extensive washes. Surface roughness and bacterial surface polarity does not influence the adhesion of Staphylococcus epidermidis, however, the material coated surface became extremely hydrophilic. The phenotype of S. epidermidis does not seem to have been affected by the contact with surfactant, reinforcing the evidence that a physical phenomenon is responsible for the activity. This paper presents a simple method of surface coating employing a synthetic surfactant to prevent S. epidermidis biofilm formation.

Relative Contribution of P5 and Hap Surface Proteins to Nontypable Haemophilus influenzae Interplay with the Host Upper and Lower Airways

PubMed Central

Viadas, Cristina; Ruiz de los Mozos, Igor; Valle, Jaione; Bengoechea, José Antonio; Garmendia, Junkal

2015-01-01

Nontypable Haemophilus influenzae (NTHi) is a major cause of opportunistic respiratory tract disease, and initiates infection by colonizing the nasopharynx. Bacterial surface proteins play determining roles in the NTHi-airways interplay, but their specific and relative contribution to colonization and infection of the respiratory tract has not been addressed comprehensively. In this study, we focused on the ompP5 and hap genes, present in all H. influenzae genome sequenced isolates, and encoding the P5 and Hap surface proteins, respectively. We employed isogenic single and double mutants of the ompP5 and hap genes generated in the pathogenic strain NTHi375 to evaluate P5 and Hap contribution to biofilm growth under continuous flow, to NTHi adhesion, and invasion/phagocytosis on nasal, pharyngeal, bronchial, alveolar cultured epithelial cells and alveolar macrophages, and to NTHi murine pulmonary infection. We show that P5 is not required for bacterial biofilm growth, but it is involved in NTHi interplay with respiratory cells and in mouse lung infection. Mechanistically, P5NTHi375 is not a ligand for CEACAM1 or α5 integrin receptors. Hap involvement in NTHi375-host interaction was shown to be limited, despite promoting bacterial cell adhesion when expressed in H. influenzae RdKW20. We also show that Hap does not contribute to bacterial biofilm growth, and that its absence partially restores the deficiency in lung infection observed for the ΔompP5 mutant. Altogether, this work frames the relative importance of the P5 and Hap surface proteins in NTHi virulence. PMID:25894755

Influence of freezing stress on morphological alteration and biofilm formation by Listeria monocytogenes: relationship with cell surface hydrophobicity and membrane fluidity.

PubMed

Miladi, Hanene; Ammar, Emna; Ben Slama, Rihab; Sakly, Nawfel; Bakhrouf, Amina

2013-11-01

The morphological changes and adhesive property of three Listeria monocytogenes strains submitted to freezing stress (-20 °C) were studied. The atomic force micrographs showed a reduction in the cell size and an evolution to coccoid shape. The phenotypic slime production of L. monocytogenes and the expression of the adhesive gene were investigated before and after 10 months of incubation in salmon at -20°. Our results showed that after ten months, stressed stains become more adherent and able to produce slime. In addition, we noted that this pathogen presents same physiological changes to adapt to starvation conditions. The cellular fatty acids composition of adhered and floating cells of three L. monocytogenes strains was taken into consideration. The stressed strains presented different chain lengths and therefore an increase in the hydrophobicity level. Moreover, we noted that the adhesive property of L. monocytogenes strains affects the Benzalkonium chloride bacterial sensitivity which increased after biofilm formation.

Glycan-functionalized diamond nanoparticles as potent E. coli anti-adhesives.

PubMed

Barras, Alexandre; Martin, Fernando Ariel; Bande, Omprakash; Baumann, Jean-Sébastien; Ghigo, Jean-Marc; Boukherroub, Rabah; Beloin, Christophe; Siriwardena, Aloysius; Szunerits, Sabine

2013-03-21

Bacterial attachment and subsequent biofilm formation on biotic surfaces or medical devices is an increasing source of infections in clinical settings. A large proportion of these biofilm-related infections are caused by Escherichia coli, a major nosocomial pathogen, in which the major adhesion factor is the FimH adhesin located at the tip of type 1 fimbriae. Inhibition of FimH-mediated adhesion has been identified as an efficient antibiotic-alternative strategy to potentially reduce E. coli-related infections. In this article we demonstrate that nanodiamond particles, covently modified with mannose moieties by a "click" chemistry approach, are able to efficiently inhibit E. coli type 1 fimbriae-mediated adhesion to eukaryotic cells with relative inhibitory potency (RIP) of as high as 9259 (bladder cell adhesion assay), which is unprecedented when compared with RIP values previously reported for alternate multivalent mannose-functionalized nanostructures designed to inhibit E. coli adhesion. Also remarkable is that these novel mannose-modified NDs reduce E. coli biofilm formation, a property previously not observed for multivalent glyco-nanoparticles and rarely demonstrated for other multivalent or monovalent mannose glycans. This work sets the stage for the further evaluation of these novel NDs as an anti-adhesive therapeutic strategy against E. coli-derived infections.

[In vitro comparison of epidural bacteria filters permeability and screening scanning electron microscopy].

PubMed

Sener, Aysin; Erkin, Yuksel; Sener, Alper; Tasdogen, Aydin; Dokumaci, Esra; Elar, Zahide

2015-01-01

Epidural catheter bacteria filters are barriers in the patient-controlled analgesia/anaesthesia for preventing contamination at the epidural insertion site. The efficiency of these filters varies according to pore sizes and materials. The bacterial adhesion capability of the two filters was measured in vitro experiment. Adhesion capacities for standard Staphylococcus aureus (ATCC 25923) and Pseudomonas aeruginosa (ATCC 27853) strains of the two different filters (Portex and Rusch) which have the same pore size were examined. Bacterial suspension of 0.5 Mc Farland was placed in the patient-controlled analgesia pump, was filtered at a speed of 5mL/h. in continuous infusion for 48h and accumulated in bottle. The two filters were compared with colony counts of bacteria in the filters and bottles. At the same time, the filters and adhered bacteria were monitored by scanning electron microscope. Electron microscopic examination of filters showed that the Portex filter had a granular and the Rusch filter fibrillary structure. Colony counting from the catheter and bottle showed that both of the filters have significant bacterial adhesion capability (p<0.001). After the bacteria suspension infusion, colony countings showed that the Portex filter was more efficient (p<0.001). There was not any difference between S. aureus and P. aeruginosa bacteria adhesion. In the SEM monitoring after the infusion, it was physically shown that the bacteria were adhered efficiently by both of the filters. The granular structured filter was found statistically and significantly more successful than the fibrial. Although the pore sizes of the filters were same - of which structural differences shown by SEM were the same - it would not be right to attribute the changes in the efficiencies to only structural differences. Using microbiological and physical proofs with regard to efficiency at the same time has been another important aspect of this experiment. Copyright © 2013 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

In vitro comparison of epidural bacteria filters permeability and screening scanning electron microscopy.

PubMed

Sener, Aysin; Erkin, Yuksel; Sener, Alper; Tasdogen, Aydin; Dokumaci, Esra; Elar, Zahide

2015-01-01

Epidural catheter bacteria filters are barriers in the patient-controlled analgesia/anaesthesia for preventing contamination at the epidural insertion site. The efficiency of these filters varies according to pore sizes and materials. The bacterial adhesion capability of the two filters was measured in vitro experiment. Adhesion capacities for standard Staphylococcus aureus (ATCC 25923) and Pseudomonas aeruginosa (ATCC 27853) strains of the two different filters (Portex and Rusch) which have the same pore size were examined. Bacterial suspension of 0.5 Mc Farland was placed in the patient-controlled analgesia pump, was filtered at a speed of 5 mL/h. in continuous infusion for 48 h and accumulated in bottle. The two filters were compared with colony counts of bacteria in the filters and bottles. At the same time, the filters and adhered bacteria were monitored by scanning electron microscope. Electron microscopic examination of filters showed that the Portex filter had a granular and the Rusch filter fibrillary structure. Colony counting from the catheter and bottle showed that both of the filters have significant bacterial adhesion capability (p<0.001). After the bacteria suspension infusion, colony countings showed that the Portex filter was more efficient (p<0.001). There was not any difference between S. aureus and P. aeruginosa bacteria adhesion. In the SEM monitoring after the infusion, it was physically shown that the bacteria were adhered efficiently by both of the filters. The granular structured filter was found statistically and significantly more successful than the fibrial. Although the pore sizes of the filters were same - of which structural differences shown by SEM were the same - it would not be right to attribute the changes in the efficiencies to only structural differences. Using microbiological and physical proofs with regard to efficiency at the same time has been another important aspect of this experiment. Copyright © 2013 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

Vulvovaginitis and other common childhood gynaecological conditions.

PubMed

Garden, Anne S

2011-04-01

Paediatric gynaecological problems, especially those involving the vulvar area, are common in childhood. The conditions frequently seen include recurrent bacterial vulvovaginitis, vulvar irritation, labial adhesions and dermatological conditions. The presentation and management of these conditions will be reviewed.

Bioactive Coatings for Orthopaedic Implants—Recent Trends in Development of Implant Coatings

PubMed Central

Zhang, Bill G. X.; Myers, Damian E.; Wallace, Gordon G.; Brandt, Milan; Choong, Peter F. M.

2014-01-01

Joint replacement is a major orthopaedic procedure used to treat joint osteoarthritis. Aseptic loosening and infection are the two most significant causes of prosthetic implant failure. The ideal implant should be able to promote osteointegration, deter bacterial adhesion and minimize prosthetic infection. Recent developments in material science and cell biology have seen the development of new orthopaedic implant coatings to address these issues. Coatings consisting of bioceramics, extracellular matrix proteins, biological peptides or growth factors impart bioactivity and biocompatibility to the metallic surface of conventional orthopaedic prosthesis that promote bone ingrowth and differentiation of stem cells into osteoblasts leading to enhanced osteointegration of the implant. Furthermore, coatings such as silver, nitric oxide, antibiotics, antiseptics and antimicrobial peptides with anti-microbial properties have also been developed, which show promise in reducing bacterial adhesion and prosthetic infections. This review summarizes some of the recent developments in coatings for orthopaedic implants. PMID:25000263

Serratia marcescens Suppresses Host Cellular Immunity via the Production of an Adhesion-inhibitory Factor against Immunosurveillance Cells*

PubMed Central

Ishii, Kenichi; Adachi, Tatsuo; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

2014-01-01

Injection of a culture supernatant of Serratia marcescens into the bloodstream of the silkworm Bombyx mori increased the number of freely circulating immunosurveillance cells (hemocytes). Using a bioassay with live silkworms, serralysin metalloprotease was purified from the culture supernatant and identified as the factor responsible for this activity. Serralysin inhibited the in vitro attachment of both silkworm hemocytes and murine peritoneal macrophages. Incubation of silkworm hemocytes or murine macrophages with serralysin resulted in degradation of the cellular immune factor BmSPH-1 or calreticulin, respectively. Furthermore, serralysin suppressed in vitro phagocytosis of bacteria by hemocytes and in vivo bacterial clearance in silkworms. Disruption of the ser gene in S. marcescens attenuated its host killing ability in silkworms and mice. These findings suggest that serralysin metalloprotease secreted by S. marcescens suppresses cellular immunity by decreasing the adhesive properties of immunosurveillance cells, thereby contributing to bacterial pathogenesis. PMID:24398686

Serratia marcescens suppresses host cellular immunity via the production of an adhesion-inhibitory factor against immunosurveillance cells.

PubMed

Ishii, Kenichi; Adachi, Tatsuo; Hamamoto, Hiroshi; Sekimizu, Kazuhisa

2014-02-28

Injection of a culture supernatant of Serratia marcescens into the bloodstream of the silkworm Bombyx mori increased the number of freely circulating immunosurveillance cells (hemocytes). Using a bioassay with live silkworms, serralysin metalloprotease was purified from the culture supernatant and identified as the factor responsible for this activity. Serralysin inhibited the in vitro attachment of both silkworm hemocytes and murine peritoneal macrophages. Incubation of silkworm hemocytes or murine macrophages with serralysin resulted in degradation of the cellular immune factor BmSPH-1 or calreticulin, respectively. Furthermore, serralysin suppressed in vitro phagocytosis of bacteria by hemocytes and in vivo bacterial clearance in silkworms. Disruption of the ser gene in S. marcescens attenuated its host killing ability in silkworms and mice. These findings suggest that serralysin metalloprotease secreted by S. marcescens suppresses cellular immunity by decreasing the adhesive properties of immunosurveillance cells, thereby contributing to bacterial pathogenesis.

Heat-sterilized PD fluid blocks leukocyte adhesion and increases flow velocity in rat peritoneal venules.

PubMed

Jonasson, P; Bagge, U; Wieslander, A; Braide, M

1996-01-01

Data from cell culture experiments indicate that heat sterilization of peritoneal dialysis (PD) fluids produces cytotoxic glucose degradation products. The present vital microscopic study investigated the effects of different sterilization methods on the biocompatibility of PD fluids. Thus, heat-sterilized (commercially obtained and experimentally produced) and filter-sterilized PD fluids (pH = 5.30-5.40; 1.5% glucose) were compared with Tyrode buffer, with respect to the effects on microvascular blood flow velocity and leukocyte adhesion in the rat mesentery. Exteriorization of the mesentery produced a mild inflammation, known from the literature and characterized by the adhesive rolling of leukocytes along venular walls. Superfusion of the mesentery with filter-sterilized PD fluid had no significant effects on leukocyte rolling or flow velocity in venules 25-40 microns in diameter compared with buffer superfusion. Heat-sterilized PD fluid decreased the concentration of rolling leukocytes and increased flow velocity significantly, as compared with buffer and filter-sterilized PD fluid. The results indicate that heat sterilization of PD fluids produces substances that interact with microvascular tone and leukocyte-endothelial adhesion, which hypothetically could impair the acute, granulocyte-mediated defense against bacterial infections.

Genetic Analysis of 13 Iranian Families With Leukocyte Adhesion Deficiency Type 1.

PubMed

Teimourian, Shahram; De Boer, Martin; Roos, Dirk; Isaian, Anna; Bemanian, Mohammad Hassan; Lashkary, Sharhzad; Nabavi, Mohammad; Arshi, Saba; Nateghian, Alireza; Sayyahfar, Shirin; Sazgara, Faezeh; Taheripak, Gholamreza; Alipour Fayez, Elham

2018-05-10

Leukocyte adhesion deficiency type 1 is a rare, autosomal recessive disorder that results from mutations in the ITGB2 gene. This gene encodes the CD18 subunit of β2 integrin leukocyte adhesion cell molecules. Leukocyte adhesion deficiency type 1 is characterized by recurrent bacterial infections, impaired wound healing, inadequate pus formation, and delayed separation of the umbilical cord. Blood samples were taken from 13 patients after written consent had been obtained. Genomic DNA was extracted, and ITGB2 exons and exon-intron boundaries were amplified by polymerase chain reaction. The products were examined by Sanger sequencing. In this study, 8 different previously reported mutations (intron7+1G>A, c.715G>A, c.1777 C>T, c.843del C, c.1768T>C, c.1821C>A, Intron7+1G>A, c.1885G>A) and 2 novel mutations (c.1821C>A; p.Tyr607Ter and c.1822C>T; p.Gln608Ter) were found. c.1821C>A (p.Tyr607Ter) and c.1822C>T (p.Gln608Ter) mutations should be included in the panel of carrier detection and prenatal diagnosis.

Studies on nano-additive for the substitution of hazardous chemical substances in antifouling coatings for the protection of ship hulls.

PubMed

Zhao, Xiaodong; Fan, Weijie; Duan, Jizhou; Hou, Baorong

2014-07-01

Adhesion and growth of biofouling organisms have severe influence on the reliability, service life and environmental adaptability of marine ships. Based on the bactericidal capacity of cuprous oxide and photochemical effect of nano-additive, environment-friendly and efficient marine antifouling paints were prepared in this study. The evaluation of the antifouling paints was carried out by the laboratory method using bacteria and phytoplanktonic microorganisms as target organisms, as well as measurements with panels in shallow submergence in natural seawater. Results showed good agreement of all the tests, indicating the remarkable antifouling performance of the paints. To our knowledge, this was one of the first systematic studies on effects of nano-additive for the substitution of hazardous chemical substances in antifouling coatings for the protection of ship hulls by measurements on bacterial inhibition, algal adhesion and growth of large organisms.

Biochemical and functional characterization of the periplasmic domain of the outer membrane protein A from enterohemorrhagic Escherichia coli.

PubMed

Wang, Haiguang; Li, Qian; Fang, Yao; Yu, Shu; Tang, Bin; Na, Li; Yu, Bo; Zou, Quanming; Mao, Xuhu; Gu, Jiang

2016-01-01

Outer membrane protein A (OmpA) plays multiple roles in the physiology and pathogenesis of the zoonotic pathogen enterohemorrhagic Escherichia coli (EHEC). The N-terminus of OmpA forms a transmembrane domain (OmpA™), and the roles of this domain in bacterial pathogenesis have been well studied. However, how its C-terminal domain (OmpAper), which is located at the periplasmic space in the bacterial membrane, contributes to virulence remains unclear. Herein, we report that OmpAper forms a dimer and binds to peptidoglycan in vitro. Furthermore, OmpAper is responsible for bacterial resistance to acidic conditions, high osmotic pressure and high SDS environments. In addition, OmpAper contributes to the adhesion of bacteria to HeLa cells in vitro and ex vivo. These results provide an additional understanding of the role of OmpA in EHEC physiology and pathogenesis. Copyright © 2015 Elsevier GmbH. All rights reserved.

Design of poly(vinylidene fluoride)-g-p(hydroxyethyl methacrylate-co-N-isopropylacrylamide) membrane via surface modification for enhanced fouling resistance and release property

NASA Astrophysics Data System (ADS)

Zhao, Guili; Chen, Wei Ning

2017-03-01

Thermo-sensitive polymer poly(N-isopropylacrylamide) (PNIPAAm), hydrophilic polymer poly(hydroxyethyl methacrylate) (PHEMA) and copolymer p(hydroxyethyl methacrylate-co-N-isopropylacrylamide) [P(HEMA-co-NIPAAm)] were synthesized onto poly(vinylidene fluoride) (PVDF) membrane via atom transfer radical polymerization (ATRP) in order to improve not only fouling resistance but also fouling release property. The physicochemical properties of membranes including hydrophilicity, morphology and roughness were examined by contact angle analyzer, scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively. The antifouling property of membranes was improved remarkably after surface modification according to protein and bacterial adhesion testing, and filtration experiment. Minimum protein adsorption and bacterial adhesion were both obtained on PVDF-g-P(HEMA-co-NIPAAm) membrane, with reduction by 44% and 71% respectively compared to the pristine membrane. The minimum bacterial cells after detachment at 25 °C were observed on the PVDF-g-P(HEMA-co-NIPAAm) membrane with the detachment rate of 77%, indicating high fouling release property. The filtration testing indicated that the copolymer modified membrane exhibited high resistance to protein fouling and the foulant on the surface was released and removed easily by washing, suggesting high fouling release and easy-cleaning capacity. This study provides useful insight in the combined "fouling resistance" and "fouling release" property of P(HEMA-co-NIPAAm) for PVDF membrane modification, even for other types of the membrane in wide application.

Factors Affecting the Initial Adhesion and Retention of the Plant Pathogen Xylella fastidiosa in the Foregut of an Insect Vector

PubMed Central

Almeida, Rodrigo P. P.

2014-01-01

Vector transmission of bacterial plant pathogens involves three steps: pathogen acquisition from an infected host, retention within the vector, and inoculation of cells into susceptible tissue of an uninfected plant. In this study, a combination of plant and artificial diet systems were used to determine the importance of several genes on the initial adhesion and retention of the bacterium Xylella fastidiosa to an efficient insect vector. Mutant strains included fimbrial (fimA and pilB) and afimbrial (hxfA and hxfB) adhesins and three loci involved in regulatory systems (rpfF, rpfC, and cgsA). Transmission assays with variable retention time indicated that HxfA and HxfB were primarily important for early adhesion to vectors, while FimA was necessary for both adhesion and retention. The long pilus protein PilB was not deficient in initial adhesion but may be important for retention. Genes upregulated under the control of rpfF are important for both initial adhesion and retention, as transmission rates of this mutant strain were initially low and decreased over time, while disruption of rpfC and cgsA yielded trends similar to that shown by the wild-type control. Because induction of an X. fastidiosa transmissible state requires pectin, a series of experiments were used to test the roles of a polygalacturonase (pglA) and the pectin and galacturonic acid carbohydrates on the transmission of X. fastidiosa. Results show that galacturonic acid, or PglA activity breaking pectin into its major subunit (galacturonic acid), is required for X. fastidiosa vector transmission using an artificial diet system. This study shows that early adhesion and retention of X. fastidiosa are mediated by different factors. It also illustrates that the interpretation of results of vector transmission experiments, in the context of vector-pathogen interaction studies, is highly dependent on experimental design. PMID:24185853

Factors affecting the initial adhesion and retention of the plant pathogen Xylella fastidiosa in the foregut of an insect vector.

PubMed

Killiny, Nabil; Almeida, Rodrigo P P

2014-01-01

Vector transmission of bacterial plant pathogens involves three steps: pathogen acquisition from an infected host, retention within the vector, and inoculation of cells into susceptible tissue of an uninfected plant. In this study, a combination of plant and artificial diet systems were used to determine the importance of several genes on the initial adhesion and retention of the bacterium Xylella fastidiosa to an efficient insect vector. Mutant strains included fimbrial (fimA and pilB) and afimbrial (hxfA and hxfB) adhesins and three loci involved in regulatory systems (rpfF, rpfC, and cgsA). Transmission assays with variable retention time indicated that HxfA and HxfB were primarily important for early adhesion to vectors, while FimA was necessary for both adhesion and retention. The long pilus protein PilB was not deficient in initial adhesion but may be important for retention. Genes upregulated under the control of rpfF are important for both initial adhesion and retention, as transmission rates of this mutant strain were initially low and decreased over time, while disruption of rpfC and cgsA yielded trends similar to that shown by the wild-type control. Because induction of an X. fastidiosa transmissible state requires pectin, a series of experiments were used to test the roles of a polygalacturonase (pglA) and the pectin and galacturonic acid carbohydrates on the transmission of X. fastidiosa. Results show that galacturonic acid, or PglA activity breaking pectin into its major subunit (galacturonic acid), is required for X. fastidiosa vector transmission using an artificial diet system. This study shows that early adhesion and retention of X. fastidiosa are mediated by different factors. It also illustrates that the interpretation of results of vector transmission experiments, in the context of vector-pathogen interaction studies, is highly dependent on experimental design.

An assessment of adhesion, aggregation and surface charges of Lactobacillus strains derived from the human oral cavity.

PubMed

Piwat, S; Sophatha, B; Teanpaisan, R

2015-07-01

There is limited information concerning the adhesion and aggregation of human oral lactobacilli. In this study, the adhesion of 10 Lactobacillus species was investigated using H357 oral keratinocyte cells as an in vitro model for oral mucosa. Coaggregation with the representative oral pathogen, Streptococcus mutans ATCC 25175, and the physicochemical cell properties was also evaluated. The results demonstrated significant variations in adhesion (42-96%) and aggregation (autoaggregation, 14-95%; coaggregation, 19-65%). All strains showed a high affinity for chloroform, and most strains had a moderate-to-high hydrophobicity. All strains, except Lactobacillus casei and Lactobacillus gasseri, showed a moderate affinity for ethyl acetate. There was a strong association of autoaggregation with coaggregation (rs = 0·883, P < 0·001). The highest mean for autoaggregation (74%) and coaggregation (47%) belonged to the Lact. gasseri strains. Correlations between the adhesion and surface characteristics and aggregation were observed among the Lactobacillus fermentum and Lactobacillus paracasei strains; however, there was a variation in the strains properties within and between species. This study indicated that the Lact. gasseri, Lact. fermentum, and Lact. paracasei strains might be potential probiotics for the human oral cavity given their desirable properties. It should also be emphasized that a selective process for probiotic strains is required. Adhesion to host tissues and bacterial aggregation (auto- and coaggregation) are the highly important criteria for selecting strains with probiotic potential. These abilities are commonly involved with surface-charged characteristics. This is the first study to investigate the oral Lactobacillus species using an oral keratinocyte cell line. Significant results were found for the correlations between the adhesion and surface charge characteristics and for aggregation among certain strains of Lactobacillus gasseri, Lactobacillus fermentum and Lactobacillus paracasei. This observation could be useful when collecting background information for the selection of probiotic strains for use in oral health. © 2015 The Society for Applied Microbiology.

Microscale spatial analysis provides evidence for adhesive monopolization of dietary nutrients by specific intestinal bacteria

PubMed Central

Takada, Toshihiko; Nagata, Yuriko; Kado, Shoichi; Kushiro, Akira

2017-01-01

Each species of intestinal bacteria requires a nutritional source to maintain its population in the intestine. Dietary factors are considered to be major nutrients; however, evidence directly explaining the in situ utilization of dietary factors is limited. Microscale bacterial distribution would provide clues to understand bacterial lifestyle and nutrient utilization. However, the detailed bacterial localization around dietary factors in the intestine remains uninvestigated. Therefore, we explored microscale habitats in the murine intestine by using histology and fluorescent in situ hybridization, focusing on dietary factors. This approach successfully revealed several types of bacterial colonization. In particular, bifidobacterial colonization and adhesion on granular starch was frequently and commonly observed in the jejunum and distal colon. To identify the bacterial composition of areas around starch granules and areas without starch, laser microdissection and next-generation sequencing-based 16S rRNA microbial profiling was performed. It was found that Bifidobacteriaceae were significantly enriched by 4.7 fold in peri-starch areas compared to ex-starch areas. This family solely consisted of Bifidobacterium pseudolongum. In contrast, there was no significant enrichment among the other major families. This murine intestinal B. pseudolongum had starch-degrading activity, confirmed by isolation from the mouse feces and in vitro analysis. Collectively, our results demonstrate the significance of starch granules as a major habitat and potential nutritional niche for murine intestinal B. pseudolongum. Moreover, our results suggest that colonizing bifidobacteria effectively utilize starch from the closest location and maintain the location. This may be a bacterial strategy to monopolize solid dietary nutrients. We believe that our analytical approach could possibly be applied to other nutritional factors, and can be a powerful tool to investigate in vivo relationships between bacteria and environmental factors in the intestine. PMID:28394924

Microscale spatial analysis provides evidence for adhesive monopolization of dietary nutrients by specific intestinal bacteria.

PubMed

Nagara, Yusuke; Takada, Toshihiko; Nagata, Yuriko; Kado, Shoichi; Kushiro, Akira

2017-01-01

Each species of intestinal bacteria requires a nutritional source to maintain its population in the intestine. Dietary factors are considered to be major nutrients; however, evidence directly explaining the in situ utilization of dietary factors is limited. Microscale bacterial distribution would provide clues to understand bacterial lifestyle and nutrient utilization. However, the detailed bacterial localization around dietary factors in the intestine remains uninvestigated. Therefore, we explored microscale habitats in the murine intestine by using histology and fluorescent in situ hybridization, focusing on dietary factors. This approach successfully revealed several types of bacterial colonization. In particular, bifidobacterial colonization and adhesion on granular starch was frequently and commonly observed in the jejunum and distal colon. To identify the bacterial composition of areas around starch granules and areas without starch, laser microdissection and next-generation sequencing-based 16S rRNA microbial profiling was performed. It was found that Bifidobacteriaceae were significantly enriched by 4.7 fold in peri-starch areas compared to ex-starch areas. This family solely consisted of Bifidobacterium pseudolongum. In contrast, there was no significant enrichment among the other major families. This murine intestinal B. pseudolongum had starch-degrading activity, confirmed by isolation from the mouse feces and in vitro analysis. Collectively, our results demonstrate the significance of starch granules as a major habitat and potential nutritional niche for murine intestinal B. pseudolongum. Moreover, our results suggest that colonizing bifidobacteria effectively utilize starch from the closest location and maintain the location. This may be a bacterial strategy to monopolize solid dietary nutrients. We believe that our analytical approach could possibly be applied to other nutritional factors, and can be a powerful tool to investigate in vivo relationships between bacteria and environmental factors in the intestine.

Effect of Hyaluronic Acid Incorporation Method on the Stability and Biological Properties of Polyurethane-Hyaluronic Acid Biomaterials

PubMed Central

Ruiz, Amaliris; Rathnam, Kashmila R.; Masters, Kristyn S.

2014-01-01

The high failure rate of small diameter vascular grafts continues to drive the development of new materials and modification strategies that address this clinical problem, with biomolecule incorporation typically achieved via surface-based modification of various biomaterials. In this work, we examined whether the method of biomolecule incorporation (i.e., bulk vs. surface modification) into a polyurethane (PU) polymer impacted biomaterial performance in the context of vascular applications. Specifically, hyaluronic acid (HA) was incorporated into a poly(ether urethane) via bulk copolymerization or covalent surface tethering, and the resulting PU-HA materials characterized with respect to both physical and biological properties. Modification of PU with HA by either surface or bulk methods yielded materials that, when tested under static conditions, possessed no significant differences in their ability to resist protein adsorption, platelet adhesion, and bacterial adhesion, while supporting endothelial cell culture. However, only bulk-modified PU-HA materials were able to fully retain these characteristics following material exposure to flow, demonstrating a superior ability to retain the incorporated HA and minimize enzymatic degradation, protein adsorption, platelet adhesion, and bacterial adhesion. Thus, despite bulk methods rarely being implemented in the context of biomolecule attachment, these results demonstrate improved performance of PU-HA upon bulk, rather than surface, incorporation of HA. Although explored only in the context of PU-HA, the findings revealed by these experiments have broader implications for the design and evaluation of vascular graft modification strategies. PMID:24276670

Elevated liver stiffness is linked to increased biomarkers of inflammation and immune activation in HIV/hepatitis C virus-coinfected patients.

PubMed

Medrano, Luz M; Garcia-Broncano, Pilar; Berenguer, Juan; González-García, Juan; Jiménez-Sousa, Ma Ángeles; Guardiola, Josep M; Crespo, Manuel; Quereda, Carmen; Sanz, José; Canorea, Isabel; Carrero, Ana; Hontañón, Victor; Muñoz-Fernández, Ma Ángeles; Resino, Salvador

2018-06-01

Immune dysregulation is a hallmark of HIV and hepatitis C virus (HCV) infections. We aimed to evaluate the relationship between liver stiffness measurement (LSM) and biomarkers of T-cell activation, bacterial translocation, inflammation, endothelial dysfunction, and coagulopathy in HIV/HCV-coinfected patients. Cross-sectional study. We studied 238 HIV/HCV-coinfected patients, 32 healthy controls, and 39 HIV-monoinfected patients. Patients were stratified according to LSM into four groups: less than 12.5, 12.5-25, 25-40, and more than 40 kPa. T-cell subsets were measured using flow cytometry and plasma biomarkers using immunoassays. HIV/HCV-coinfected patients had higher biomarker levels of immune activation in peripheral blood [T-cell activation (CD4CD38 and CD8CD38), bacterial translocation (soluble CD14), inflammation [IL-1b, IL-6, IL-8, IL-18, IFN-γ-inducible protein 10 (IP-10)] endothelial dysfunction [soluble vascular cell adhesion molecule 1 (sVCAM1), soluble intercellular cell adhesion molecule 1 (sICAM1), and soluble tumor necrosis factor receptor 1 (sTNFR1)], and coagulopathy (plasminogen activator inhibitor-1)] than healthy controls and HIV-monoinfected patients. Moreover, in HIV/HCV-coinfected patients, a direct relationship between LSM and immune activation [T-cell activation (CD8CD38 bacterial translocation (lipopolysaccharide), inflammation (IL-8, IP-10), endothelial dysfunction (sVCAM1, sICAM1, and sTNFR1), and coagulopathy (D-dimer)] was found. Subsequently, patients were stratified into different fibrosis stages, finding that patients with cirrhosis who had LSM at least 40 kPa showed higher biomarker values of immune activation [T-cell activation (CD4CD38 and CD8CD38), bacterial translocation (lipopolysaccharide), inflammation (IL-8, IL-6, IP-10), endothelial dysfunction (sVCAM1, sICAM1, and sTNFR1), and coagulopathy (D-dimer)] than patients from the other three groups (<12.5, 12.5-25, and 25-40 kPa). T-cell activation, bacterial translocation, inflammation, endothelial dysfunction, and coagulopathy increased with the severity of liver fibrosis in HIV/HCV-coinfected patients, particularly in patients who had LSM at least 40 kPa.

Sortase A Inhibitors: Recent Advances and Future Perspectives.

PubMed

Cascioferro, Stella; Raffa, Demetrio; Maggio, Benedetta; Raimondi, Maria Valeria; Schillaci, Domenico; Daidone, Giuseppe

2015-12-10

Here, we describe the most promising small synthetic organic compounds that act as potent Sortase A inhibitors and cater the potential to be developed as antivirulence drugs. Sortase A is a polypeptide of 206 amino acids, which catalyzes two sequential reactions: (i) thioesterification and (ii) transpeptidation. Sortase A is involved in the process of bacterial adhesion by anchoring LPXTG-containing proteins to lipid II. Sortase A inhibitors do not affect bacterial growth, but they restrain the virulence of pathogenic bacterial strains, thereby preventing infections caused by Staphylococcus aureus or other Gram-positive bacteria. The efficacy of the most promising inhibitors needs to be comprehensively evaluated in in vivo models of infection, in order to select compounds eligible for the treatment of bacterial infections in humans.

Surface roughness and bacterial adhesion on root dentin treated with diode laser and conventional desensitizing agents.

PubMed

Cury, Maiza S; Silva, Camilla B; Nogueira, Ruchele D; Campos, Michelle G D; Palma-Dibb, Regina G; Geraldo-Martins, Vinicius R

2018-02-01

The treatments for dentin hypersensitivity (DH) may change the surface roughness of the root dentin, which can lead to biofilm accumulation, increasing the risk of root caries. The aim was to compare the surface roughness of root dentin after different treatments of DH and the biofilm formation on those surfaces. After initial surface roughness (Sa) assessment, 50 bovine root fragments received the following treatments (n = 10): G 1-no treatment; G2-5% sodium fluoride varnish; G3-professional application of a desensitizing dentifrice; G4-toothbrushing with a desensitizing dentifrice; and G5-diode laser application (908 nm; 1.5 W, 20 s). The Sa was reevaluated after treatments. Afterward, all samples were incubated in a suspension of Streptococcus mutans at 37 °C for 24 h. The colony-forming units (CFU) were counted using a stereoscope, and the results were expressed in CFU/mL. The one-way ANOVA and the Tukey's tests compared the roughness data and the results obtained on the bacterial adhesion test (α = 5%). G2 (2.3 ± 1.67%) showed similar Sa variation than G1 (0.25 ± 0.41%) and G5 (5.69 ± 0.99%), but different from group G3 (9.05 ± 2.39%). Group 4 showed the highest Sa variation (30.02 ± 3.83%; p < 0.05). Bacterial adhesion was higher in G4 (2208 ± 211.9), suggesting that bacterial growth is greater on rougher surfaces. The diode laser and the conventional treatments for DH may change the surface roughness of the root dentin, but only brushing with desensitizing dentifrice induced a higher bacteria accumulation on root dentin surface.

Antibacterial Surface Treatment for Orthopaedic Implants

PubMed Central

Gallo, Jiri; Holinka, Martin; Moucha, Calin S.

2014-01-01

It is expected that the projected increased usage of implantable devices in medicine will result in a natural rise in the number of infections related to these cases. Some patients are unable to autonomously prevent formation of biofilm on implant surfaces. Suppression of the local peri-implant immune response is an important contributory factor. Substantial avascular scar tissue encountered during revision joint replacement surgery places these cases at an especially high risk of periprosthetic joint infection. A critical pathogenic event in the process of biofilm formation is bacterial adhesion. Prevention of biomaterial-associated infections should be concurrently focused on at least two targets: inhibition of biofilm formation and minimizing local immune response suppression. Current knowledge of antimicrobial surface treatments suitable for prevention of prosthetic joint infection is reviewed. Several surface treatment modalities have been proposed. Minimizing bacterial adhesion, biofilm formation inhibition, and bactericidal approaches are discussed. The ultimate anti-infective surface should be “smart” and responsive to even the lowest bacterial load. While research in this field is promising, there appears to be a great discrepancy between proposed and clinically implemented strategies, and there is urgent need for translational science focusing on this topic. PMID:25116685

Milk Fat Globules Hamper Adhesion of Enterohemorrhagic Escherichia coli to Enterocytes: In Vitro and in Vivo Evidence

PubMed Central

Douëllou, Thomas; Galia, Wessam; Kerangart, Stéphane; Marchal, Thierry; Milhau, Nadège; Bastien, Renaud; Bouvier, Marion; Buff, Samuel; Montel, Marie-Christine; Sergentet-Thevenot, Delphine

2018-01-01

Enterohemorrhagic Escherichia coli (EHEC; E. coli) are food-borne agents associated with gastroenteritis, enterocolitis, bloody diarrhea and the hemolytic-uremic syndrome (HUS). Bovine milk glycans have been shown to contain oligosaccharides which are similar to host epithelial cell receptors and can therefore prevent bacterial adhesion. This study aimed to describe interactions between EHEC O157:H7 EDL933 and O26:H11 21765 and milk fat globules (MFGs) in raw milk and raw milk cheese, and the impact of MFGs on EHEC strains adhesion to the intestinal tract in vitro and in vivo. Both EHEC serotypes clearly associated with native bovine MFGs and significantly limited their adhesion to a co-culture of intestinal cells. The presence of MFGs in raw milk cheese had two effects on the adhesion of both EHEC serotypes to the intestinal tracts of streptomycin-treated mice. First, it delayed and reduced EHEC excretion in mouse feces for both strains. Second, the prime implantation site for both EHEC strains was 6 cm more proximal in the intestinal tracts of mice fed with contaminated cheese containing less than 5% of fat than in those fed with contaminated cheese containing 40% of fat. Feeding mice with 40% fat cheese reduced the intestinal surface contaminated with EHEC and may therefore decrease severity of illness. PMID:29867855

Influence of Silver-hydroxyapatite Nanocomposite Coating on Biofilm Formation of Joint Prosthesis and Its Mechanism

PubMed Central

Zhao, L; Ashraf, MA

2015-01-01

ABSTRACT Background: The main reason for biomaterial related refractory infections is biofilm formation caused by bacterial adhesion on the surface of materials. Silver-hydroxyapatite (Ag/HA) nanocomposite coating can inhibit the formation of biofilm, but its mechanism is not clear. Material and Method: In order to clarify the mechanism, the amounts of biofilm on the Ag/HA composite coating and HA coating were determined, the release rates of silver nanoparticles in simulated body fluid (SBF) were detected by atomic absorption spectrometry, and the expression values of atlE, fbe, sap, iapB genes of Staphylococcus aureus were studied when they grew on Ag/HA composite coating and HA coating. Results: The amount of the biofilm on the Ag/HA composite coating was significantly less than that on the HA coating, and the bacterial adhesion was decreased. The silver nanoparticles were released continuously in SBF and the release rate decreased gradually with time. The expression values of atlE, fbe and sap were high in the initial stage of adhesion and the expression value of iapB was high in the colonies-gathering stage in the control group, but they were all significantly inhibited in the presence of Ag. Conclusion: These results indicated that the main antibacterial effect of Ag/HA composite coating was achieved by the release of silver nanoparticles. The addition of Ag inhibited the expression of genes related to biofilm formation, which in turn inhibited the formation of biofilms. This provided theoretical support for the clinical application of Ag/HA composite coating. PMID:27400164

Anchorless surface associated glycolytic enzymes from Lactobacillus plantarum 299v bind to epithelial cells and extracellular matrix proteins.

PubMed

Glenting, Jacob; Beck, Hans Christian; Vrang, Astrid; Riemann, Holger; Ravn, Peter; Hansen, Anne Maria; Antonsson, Martin; Ahrné, Siv; Israelsen, Hans; Madsen, Søren

2013-06-12

An important criterion for the selection of a probiotic bacterial strain is its ability to adhere to the mucosal surface. Adhesion is usually mediated by proteins or other components located on the outer cell surface of the bacterium. In the present study we characterized the adhesive properties of two classical intracellular enzymes glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and enolase (ENO) isolated from the outer cell surface of the probiotic bacterium Lactobacillus plantarum 299v. None of the genes encoded signal peptides or cell surface anchoring motifs that could explain their extracellular location on the bacterial surface. The presence of the glycolytic enzymes on the outer surface was verified by western blotting using polyclonal antibodies raised against the specific enzymes. GAPDH and ENO showed a highly specific binding to plasminogen and fibronectin whereas GAPDH but not ENO showed weak binding to mucin. Furthermore, a pH dependent and specific binding of GAPDH and ENO to intestinal epithelial Caco-2 cells at pH 5 but not at pH 7 was demonstrated. The results showed that these glycolytic enzymes could play a role in the adhesion of the probiotic bacterium L. plantarum 299v to the gastrointestinal tract of the host. Finally, a number of probiotic as well non-probiotic Lactobacillus strains were analyzed for the presence of GAPDH and ENO on the outer surface, but no correlation between the extracellular location of these enzymes and the probiotic status of the applied strains was demonstrated. Copyright © 2013 Elsevier GmbH. All rights reserved.

TrmFO, a Fibronectin-Binding Adhesin of Mycoplasma bovis.

PubMed

Guo, Yongpeng; Zhu, Hongmei; Wang, Jiayao; Huang, Jing; Khan, Farhan Anwar; Zhang, Jingjing; Guo, Aizhen; Chen, Xi

2017-08-09

Mycoplasma bovis is an important pathogenic mycoplasma, causing the cattle industry serious economic losses. Adhesion is a crucial step in the mycoplasmas' infection and colonization process; fibronectin (Fn), an extracellular matrix glycoprotein, is a molecular bridge between the bacterial adhesins and host cell receptors. The present study was designed to characterize the Fn-binding ability of methylenetetrahydrofolate-tRNA-(uracil-5-)-methyltransferase (TrmFO) and its role in M. bovis cytoadherence. The trmFO ( MBOV_RS00785 ) gene was cloned and expressed in E. coli BL21, and polyclonal antibodies against the recombinant TrmFO (rTrmFO) were raised in rabbits. Immunoblotting demonstrated that TrmFO was an immunogenic component, and the TrmFO expression was conserved in different M. bovis isolates. The mycoplasmacidal assay further showed that in the presence of complement, rabbit anti-recombinant TrmFO serum exhibited remarkable mycoplasmacidal efficacy. TrmFO was detected in both the M. bovis membrane and cytoplasm. By ligand dot blot and enzyme-linked immunosorbent assay (ELISA) binding assay, we found that rTrmFO bound Fn in a dose-dependent manner. Immunostaining visualized by confocal laser scanning microscopy showed that rTrmFO had capacity to adhere to the embryonic bovine lung (EBL) cells. In addition, the adhesion of M. bovis and rTrmFO to EBL cells could be inhibited by anti-rTrmFO antibodies. To the best of our knowledge, this is the first report to characterize the Fn-binding ability of TrmFO and its role in the bacterial adhesion to host cells.

TrmFO, a Fibronectin-Binding Adhesin of Mycoplasma bovis

PubMed Central

Guo, Yongpeng; Zhu, Hongmei; Wang, Jiayao; Huang, Jing; Khan, Farhan Anwar; Zhang, Jingjing; Guo, Aizhen; Chen, Xi

2017-01-01

Mycoplasma bovis is an important pathogenic mycoplasma, causing the cattle industry serious economic losses. Adhesion is a crucial step in the mycoplasmas’ infection and colonization process; fibronectin (Fn), an extracellular matrix glycoprotein, is a molecular bridge between the bacterial adhesins and host cell receptors. The present study was designed to characterize the Fn-binding ability of methylenetetrahydrofolate-tRNA-(uracil-5-)-methyltransferase (TrmFO) and its role in M. bovis cytoadherence. The trmFO (MBOV_RS00785) gene was cloned and expressed in E. coli BL21, and polyclonal antibodies against the recombinant TrmFO (rTrmFO) were raised in rabbits. Immunoblotting demonstrated that TrmFO was an immunogenic component, and the TrmFO expression was conserved in different M. bovis isolates. The mycoplasmacidal assay further showed that in the presence of complement, rabbit anti-recombinant TrmFO serum exhibited remarkable mycoplasmacidal efficacy. TrmFO was detected in both the M. bovis membrane and cytoplasm. By ligand dot blot and enzyme-linked immunosorbent assay (ELISA) binding assay, we found that rTrmFO bound Fn in a dose-dependent manner. Immunostaining visualized by confocal laser scanning microscopy showed that rTrmFO had capacity to adhere to the embryonic bovine lung (EBL) cells. In addition, the adhesion of M. bovis and rTrmFO to EBL cells could be inhibited by anti-rTrmFO antibodies. To the best of our knowledge, this is the first report to characterize the Fn-binding ability of TrmFO and its role in the bacterial adhesion to host cells. PMID:28792486

Direct Covalent Grafting of Phytate to Titanium Surfaces through Ti-O-P Bonding Shows Bone Stimulating Surface Properties and Decreased Bacterial Adhesion.

PubMed

Córdoba, Alba; Hierro-Oliva, Margarita; Pacha-Olivenza, Miguel Ángel; Fernández-Calderón, María Coronada; Perelló, Joan; Isern, Bernat; González-Martín, María Luisa; Monjo, Marta; Ramis, Joana M

2016-05-11

Myo-inositol hexaphosphate, also called phytic acid or phytate (IP6), is a natural molecule abundant in vegetable seeds and legumes. Among other functions, IP6 inhibits bone resorption. It is adsorbed on the surface of hydroxyapatite, inhibiting its dissolution and decreasing the progressive loss of bone mass. We present here a method to directly functionalize Ti surfaces covalently with IP6, without using a cross-linker molecule, through the reaction of the phosphate groups of IP6 with the TiO2 layer of Ti substrates. The grafting reaction consisted of an immersion in an IP6 solution to allow the physisorption of the molecules onto the substrate, followed by a heating step to obtain its chemisorption, in an adaptation of the T-Bag method. The reaction was highly dependent on the IP6 solution pH, only achieving a covalent Ti-O-P bond at pH 0. We evaluated two acidic pretreatments of the Ti surface, to increase its hydroxylic content, HNO3 30% and HF 0.2%. The structure of the coated surfaces was characterized by X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and ellipsometry. The stability of the IP6 coating after three months of storage and after sterilization with γ-irradiation was also determined. Then, we evaluated the biological effect of Ti-IP6 surfaces in vitro on MC3T3-E1 osteoblastic cells, showing an osteogenic effect. Finally, the effect of the surfaces on the adhesion and biofilm viability of oral microorganisms S. mutans and S. sanguinis was also studied, and we found that Ti-IP6 surfaces decreased the adhesion of S. sanguinis. A surface that actively improves osseointegration while decreasing the bacterial adhesion could be suitable for use in bone implants.

Is there a role for lactobacilli in prevention of urogenital and intestinal infections?

PubMed Central

Reid, G; Bruce, A W; McGroarty, J A; Cheng, K J; Costerton, J W

1990-01-01

This review describes the importance of microbial adhesion in the ecology of the urogenital and intestinal tracts and the influence of host and microbial factors in bacterial interference. In a recent revival of interest in bacterial interference, lactobacillus administration has been studied as a means of treating and preventing disease. Although evidence is conflicting, Lactobacillus acidophilus appears to be involved in beneficial antagonistic and cooperative reactions that interfere with establishment of pathogens in the gastrointestinal tract. The mechanisms of action are believed to involve competitive exclusion and production of inhibitory substances, including bacteriocins. These characteristics, as well as demonstrated adherence abilities in vitro, led to selection of certain Lactobacillus strains for clinical studies of cystitis. Weekly intravaginal Lactobacillus therapy reduced the recurrence rate of uncomplicated lower urinary tract infections in women. Use of Lactobacillus strains resistant to Nonoxynol-9, a spermicide that kills members of the protective normal vaginal flora, may have potential for use in women with recurrent cystitis using this contraceptive agent. In veterinary studies, bacterial interference by administration of probiotics has also been beneficial in disease prevention in animals. Carefully selected bacterial mixtures integrate with the gastrointestinal flora of the animals and can confer disease resistance and improve physiological function. Additional human and animal trials are needed to determine the practical, long-term usefulness of bacterial interference as a protective mechanism against infectious diseases. Images PMID:2224835

2-Methacryloyloxyethyl phosphorylcholine (MPC)-polymer suppresses an increase of oral bacteria: a single-blind, crossover clinical trial.

PubMed

Fujiwara, Natsumi; Yumoto, Hiromichi; Miyamoto, Koji; Hirota, Katsuhiko; Nakae, Hiromi; Tanaka, Saya; Murakami, Keiji; Kudo, Yasusei; Ozaki, Kazumi; Miyake, Yoichiro

2018-05-16

The biocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC)-polymers, which mimic a biomembrane, reduce protein adsorption and bacterial adhesion and inhibit cell attachment. The aim of this study is to clarify whether MPC-polymer can suppress the bacterial adherence in oral cavity by a crossover design. We also investigated the number of Fusobacterium nucleatum, which is the key bacterium forming dental plaque, in clinical samples. This study was a randomized, placebo-controlled, single-blind, crossover study, with two treatment periods separated by a 2-week washout period. We conducted clinical trial with 20 healthy subjects to evaluate the effect of 5% MPC-polymer mouthwash after 5 h on oral microflora. PBS was used as a control. The bacterial number in the gargling sample before and after intervention was counted by an electronic bacterial counter and a culture method. DNA amounts of total bacteria and F. nucleatum were examined by q-PCR. The numbers of total bacteria and oral streptcocci after 5 h of 5% MPC-polymer treatment significantly decreased, compared to the control group. Moreover, the DNA amounts of total bacteria and F. nucleatum significantly decreased by 5% MPC-polymer mouthwash. We suggest that MPC-polymer coating in the oral cavity may suppress the oral bacterial adherence. MPC-polymer can be a potent compound for the control of oral microflora to prevent oral infection.

Crystal structure of the Haemophilus influenzae Hap adhesin reveals an intercellular oligomerization mechanism for bacterial aggregation

PubMed Central

Meng, Guoyu; Spahich, Nicole; Kenjale, Roma; Waksman, Gabriel; St Geme, Joseph W

2011-01-01

Bacterial biofilms are complex microbial communities that are common in nature and are being recognized increasingly as an important determinant of bacterial virulence. However, the structural determinants of bacterial aggregation and eventual biofilm formation have been poorly defined. In Gram-negative bacteria, a major subgroup of extracellular proteins called self-associating autotransporters (SAATs) can mediate cell–cell adhesion and facilitate biofilm formation. In this study, we used the Haemophilus influenzae Hap autotransporter as a prototype SAAT to understand how bacteria associate with each other. The crystal structure of the H. influenzae HapS passenger domain (harbouring the SAAT domain) was determined to 2.2 Å by X-ray crystallography, revealing an unprecedented intercellular oligomerization mechanism for cell–cell interaction. The C-terminal SAAT domain folds into a triangular-prism-like structure that can mediate Hap–Hap dimerization and higher degrees of multimerization through its F1–F2 edge and F2 face. The intercellular multimerization can give rise to massive buried surfaces that are required for overcoming the repulsive force between cells, leading to bacterial cell–cell interaction and formation of complex microcolonies. PMID:21841773

A Murine Model for Escherichia coli Urinary Tract Infection.

PubMed

Hannan, Thomas J; Hunstad, David A

2016-01-01

Urinary tract infections (UTI) are among the most common bacterial infections of humans. The mouse provides an excellent and tractable model system for cystitis and pyelonephritis caused by Escherichia coli and other uropathogens. Using a well-established model of experimental cystitis in which the bladders of female mice are infected via transurethral catheterization, the molecular details of the pathogenesis of bacterial cystitis have been substantially illuminated in the last decade. Uropathogenic E. coli attach to bladder epithelium (both in human and mouse) via adhesive type 1 pili, establish a replicative niche within epithelial cell cytoplasm, and form intracellular bacterial communities that are protected from antibiotic effects and immune clearance. The use of different inbred and mutant mouse strains offers the opportunity to study outcomes of infection, including resolution, formation of quiescent intracellular bacterial reservoirs, chronic bacterial cystitis, and recurrent infections. Urine, bladder, and kidney tissues can be analyzed by bacterial culture, histology, immunohistochemistry, immunofluorescent and confocal microscopy, electron microscopy, and flow cytometry, while a broad array of soluble markers (e.g., cytokines) can also be profiled in serum, urine, and tissue homogenates by ELISA, Western blotting, multiplex bead array, and other approaches. This model promises to afford continued opportunity for discovery of pathogenic mechanisms and evaluation of therapeutic and preventive strategies for acute, chronic, and recurrent UTI.

Silver nanoparticle-doped zirconia capillaries for enhanced bacterial filtration.

PubMed

Wehling, Julia; Köser, Jan; Lindner, Patrick; Lüder, Christian; Beutel, Sascha; Kroll, Stephen; Rezwan, Kurosch

2015-03-01

Membrane clogging and biofilm formation are the most serious problems during water filtration. Silver nanoparticle (Agnano) coatings on filtration membranes can prevent bacterial adhesion and the initiation of biofilm formation. In this study, Agnano are immobilized via direct reduction on porous zirconia capillary membranes to generate a nanocomposite material combining the advantages of ceramics being chemically, thermally and mechanically stable with nanosilver, an efficient broadband bactericide for water decontamination. The filtration of bacterial suspensions of the fecal contaminant Escherichia coli reveals highly efficient bacterial retention capacities of the capillaries of 8 log reduction values, fulfilling the requirements on safe drinking water according to the U.S. Environmental Protection Agency. Maximum bacterial loading capacities of the capillary membranes are determined to be 3×10(9)bacterialcells/750mm(2) capillary surface until back flushing is recommendable. The immobilized Agnano remain accessible and exhibit strong bactericidal properties by killing retained bacteria up to maximum bacterial loads of 6×10(8)bacterialcells/750mm(2) capillary surface and the regenerated membranes regain filtration efficiencies of 95-100%. Silver release is moderate as only 0.8% of the initial silver loading is leached during a three-day filtration experiment leading to average silver contaminant levels of 100μg/L. Copyright © 2014 Elsevier B.V. All rights reserved.

Nanopatterning of steel by one-step anodization for anti-adhesion of bacteria.

PubMed

Chen, Shiqiang; Li, Yuan; Cheng, Y Frank

2017-07-13

Surface nanopatterning of metals has been an effective technique for improved performance and functionalization. However, it is of great challenge to fabricate nanostructure on carbon steels despite their extensive use and urgent needs to maintain the performance reliability and durability. Here, we report a one-step anodization technique to nanopattern a carbon steel in 50 wt.% NaOH solution for highly effective anti-adhesion by sulphate reducing bacteria (SRB), i.e., Desulfovibrio desulfuricans subsp. desulfuricans (Beijerinck) Kluyver and van Niel. We characterize the morphology, structure, composition, and surface roughness of the nanostructured film formed on the steel as a function of anodizing potential. We quantify the surface hydrophobicity by contact angle measurements, and the SRB adhesion by fluorescent analysis. The optimal anodization potential of 2.0 V is determined for the best performance of anti-adhesion of SRB to the steel, resulting in a 23.5 times of reduction of SRB adhesion compared to bare steel. We discuss the mechanisms for the film formation on the steel during anodization, and the high-performance anti-adhesion of bacteria to nanopatterned steels. Our technique is simple, cost-effective and environment-friendly, providing a promising alternative for industry-scale surface nanopatterning of carbon steels for effective controlling of bacterial adhesion.

Triple Antibiotic Polymer Nanofibers for Intracanal Drug Delivery: Effects on Dual Species Biofilm and Cell Function

PubMed Central

Pankajakshan, Divya; Albuquerque, Maria T.P.; Evans, Joshua D.; Kamocka, Malgorzata M.; Gregory, Richard L.; Bottino, Marco C.

2016-01-01

Introduction Root canal disinfection and the establishment of an intracanal microenvironment conducive to the proliferation/differentiation of stem cells play a significant role in regenerative endodontics. This study was designed to (1) investigate the antimicrobial efficacy of triple antibiotic–containing nanofibers against a dual-species biofilm and (2) evaluate the ability of dental pulp stem cells (DPSCs) to adhere to and proliferate on dentin upon nanofiber exposure. Methods Seven-day-old dual-species biofilm established on dentin specimens was exposed for 3 days to the following: saline (control), antibiotic-free nanofibers (control), and triple antibiotic–containing nanofibers or a saturated triple antibiotic paste (TAP) solution (50 mg/mL in phosphate buffer solution). Bacterial viability was assessed using the LIVE/DEAD assay (Molecular Probes, Inc, Eugene, OR) and confocal laser scanning microscopy. For cyto-compatibility studies, dentin specimens after nanofiber or TAP (1 g/mL in phosphate buffer solution) exposure were evaluated for cell adhesion and spreading by actin-phalloidin staining. DPSC proliferation was assessed on days 1, 3, and 7. Statistics were performed, and significance was set at the 5% level. Results Confocal laser scanning microscopy showed significant bacterial death upon antibiotic-containing nanofiber exposure, differing significantly (P < .05) from antibiotic-free fibers and the control (saline). DPSCs showed enhanced adhesion/spreading on dentin specimens treated with antibiotic-containing nanofibers when compared with its TAP counterparts. The DPSC proliferation rate was similar on days 1 and 3 in antibiotic-free nanofibers, triple antibiotic–containing nanofibers, and TAP-treated dentin. Proliferation was higher (9-fold) on dentin treated with antibiotic-containing nanofibers on day 7 compared with TAP. Conclusions Triple antibiotic–containing polymer nanofibers led to significant bacterial death, whereas they did not affect DPSC attachment and proliferation on dentin. PMID:27663615

Evidence for Escherichia coli Diguanylate Cyclase DgcZ Interlinking Surface Sensing and Adhesion via Multiple Regulatory Routes

PubMed Central

Lacanna, Egidio; Bigosch, Colette; Kaever, Volkhard; Boehm, Alex

2016-01-01

ABSTRACT DgcZ is the main cyclic dimeric GMP (c-di-GMP)-producing diguanylate cyclase (DGC) controlling biosynthesis of the exopolysaccharide poly-β-1,6-N-acetylglucosamine (poly-GlcNAc or PGA), which is essential for surface attachment of Escherichia coli. Although the complex regulation of DgcZ has previously been investigated, its primary role and the physiological conditions under which the protein is active are not fully understood. Transcription of dgcZ is regulated by the two-component system CpxAR activated by the lipoprotein NlpE in response to surface sensing. Here, we show that the negative effect of a cpxR mutation and the positive effect of nlpE overexpression on biofilm formation both depend on DgcZ. Coimmunoprecipitation data suggest several potential interaction partners of DgcZ. Interaction with FrdB, a subunit of the fumarate reductase complex (FRD) involved in anaerobic respiration and in control of flagellum assembly, was further supported by a bacterial-two-hybrid assay. Furthermore, the FRD complex was required for the increase in DgcZ-mediated biofilm formation upon induction of oxidative stress by addition of paraquat. A DgcZ-mVENUS fusion protein was found to localize at one bacterial cell pole in response to alkaline pH and carbon starvation. Based on our data and previous knowledge, an integrative role of DgcZ in regulation of surface attachment is proposed. We speculate that both DgcZ-stimulated PGA biosynthesis and interaction of DgcZ with the FRD complex contribute to impeding bacterial escape from the surface. IMPORTANCE Bacterial cells can grow by clonal expansion to surface-associated biofilms that are ubiquitous in the environment but also constitute a pervasive problem related to bacterial infections. Cyclic dimeric GMP (c-di-GMP) is a widespread bacterial second messenger involved in regulation of motility and biofilm formation, and plays a primary role in bacterial surface attachment. E. coli possesses a plethora of c-di-GMP-producing diguanylate cyclases, including DgcZ. Our study expands the knowledge on the role of DgcZ in regulation of surface attachment and suggests that it interconnects surface sensing and adhesion via multiple routes. PMID:27402625

Evidence for Escherichia coli Diguanylate Cyclase DgcZ Interlinking Surface Sensing and Adhesion via Multiple Regulatory Routes.

PubMed

Lacanna, Egidio; Bigosch, Colette; Kaever, Volkhard; Boehm, Alex; Becker, Anke

2016-09-15

DgcZ is the main cyclic dimeric GMP (c-di-GMP)-producing diguanylate cyclase (DGC) controlling biosynthesis of the exopolysaccharide poly-β-1,6-N-acetylglucosamine (poly-GlcNAc or PGA), which is essential for surface attachment of Escherichia coli Although the complex regulation of DgcZ has previously been investigated, its primary role and the physiological conditions under which the protein is active are not fully understood. Transcription of dgcZ is regulated by the two-component system CpxAR activated by the lipoprotein NlpE in response to surface sensing. Here, we show that the negative effect of a cpxR mutation and the positive effect of nlpE overexpression on biofilm formation both depend on DgcZ. Coimmunoprecipitation data suggest several potential interaction partners of DgcZ. Interaction with FrdB, a subunit of the fumarate reductase complex (FRD) involved in anaerobic respiration and in control of flagellum assembly, was further supported by a bacterial-two-hybrid assay. Furthermore, the FRD complex was required for the increase in DgcZ-mediated biofilm formation upon induction of oxidative stress by addition of paraquat. A DgcZ-mVENUS fusion protein was found to localize at one bacterial cell pole in response to alkaline pH and carbon starvation. Based on our data and previous knowledge, an integrative role of DgcZ in regulation of surface attachment is proposed. We speculate that both DgcZ-stimulated PGA biosynthesis and interaction of DgcZ with the FRD complex contribute to impeding bacterial escape from the surface. Bacterial cells can grow by clonal expansion to surface-associated biofilms that are ubiquitous in the environment but also constitute a pervasive problem related to bacterial infections. Cyclic dimeric GMP (c-di-GMP) is a widespread bacterial second messenger involved in regulation of motility and biofilm formation, and plays a primary role in bacterial surface attachment. E. coli possesses a plethora of c-di-GMP-producing diguanylate cyclases, including DgcZ. Our study expands the knowledge on the role of DgcZ in regulation of surface attachment and suggests that it interconnects surface sensing and adhesion via multiple routes. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Direct Loading and Tunable Release of Antibiotics from Polyelectrolyte Multilayers To Reduce Bacterial Adhesion and Biofilm Formation.

PubMed

Wang, Bailiang; Jin, Tingwei; Xu, Qingwen; Liu, Huihua; Ye, Zi; Chen, Hao

2016-05-18

Bacteria adhesion on the surface of biomaterials and following biofilm formation are important problems in biomedical applications. The charged antibiotics with small molar mass can hardly deposit alternately with polymers into multilayered films to load the drug. Herein, the (poly(acrylic acid)-gentamicin/poly(ethylenimine))n ((PAA-GS/PEI)n) multilayer film was designed and constructed via a layer-by-layer self-assembly method. Low molar mass GS cations were first combined with polyanion PAA and self-assembled with PEI to form multilayer films showing exponential growth behavior. The GS dosage could be adjusted by changing the layer number of films. Furthermore, the thermal cross-linking method was used to control the release rate of GS in PBS buffer. Owing to the diffusion of GS, a zone of inhibition of about 7.0 mm showed the efficient disinfection activity of the multilayer film. It could also be seen from the biofilm inhibition assay that the multilayer film effectively inhibited bacterial adhesion and biofilm formation. As the drug loading dosage was 160 μg/cm(2), the multilayer films showed very low cytotoxicity against human lens epithelial cells. The present work provides an easy way to load GS into multilayer films which can be applied to surface modification of implants and biomedical devices.

O-sulfated bacterial polysaccharides with low anticoagulant activity inhibit metastasis.

PubMed

Borgenström, Marjut; Wärri, Anni; Hiilesvuo, Katri; Käkönen, Rami; Käkönen, Sanna; Nissinen, Liisa; Pihlavisto, Marjo; Marjamäki, Anne; Vlodavsky, Israel; Naggi, Annamaria; Torri, Giangiacomo; Casu, Benito; Veromaa, Timo; Salmivirta, Markku; Elenius, Klaus

2007-07-01

Heparin-like polysaccharides possess the capacity to inhibit cancer cell proliferation, angiogenesis, heparanase-mediated cancer cell invasion, and cancer cell adhesion to vascular endothelia via adhesion receptors, such as selectins. The clinical applicability of the antitumor effect of such polysaccharides, however, is compromised by their anticoagulant activity. We have compared the potential of chemically O-sulfated and N,O-sulfated bacterial polysaccharide (capsular polysaccharide from E. COLI K5 [K5PS]) species to inhibit metastasis of mouse B16-BL6 melanoma cells and human MDA-MB-231 breast cancer cells in two in vivo models. We demonstrate that in both settings, O-sulfated K5PS was a potent inhibitor of metastasis. Reducing the molecular weight of the polysaccharide, however, resulted in lower antimetastatic capacity. Furthermore, we show that O-sulfated K5PS efficiently inhibited the invasion of B16-BL6 cells through Matrigel and also inhibited the in vitro activity of heparanase. Moreover, treatment with O-sulfated K5PS lowered the ability of B16-BL6 cells to adhere to endothelial cells, intercellular adhesion molecule-1, and P-selectin, but not to E-selectin. Importantly, O-sulfated K5PSs were largely devoid of anticoagulant activity. These findings indicate that O-sulfated K5PS polysaccharide should be considered as a potential antimetastatic agent.

Nano titania aided clustering and adhesion of beneficial bacteria to plant roots to enhance crop growth and stress management.

PubMed

Palmqvist, N G M; Bejai, S; Meijer, J; Seisenbaeva, G A; Kessler, V G

2015-05-13

A novel use of Titania nanoparticles as agents in the nano interface interaction between a beneficial plant growth promoting bacterium (Bacillus amyloliquefaciens UCMB5113) and oilseed rape plants (Brassica napus) for protection against the fungal pathogen Alternaria brassicae is presented. Two different TiO2 nanoparticle material were produced by the Sol-Gel approach, one using the patented Captigel method and the other one applying TiBALDH precursor. The particles were characterized by transmission electron microscopy, thermogravimetric analysis, X-ray diffraction, dynamic light scattering and nano particle tracking analysis. Scanning electron microscopy showed that the bacterium was living in clusters on the roots and the combined energy-dispersive X-ray spectroscopy analysis revealed that titanium was present in these cluster formations. Confocal laser scanning microscopy further demonstrated an increased bacterial colonization of Arabidopsis thaliana roots and a semi-quantitative microscopic assay confirmed an increased bacterial adhesion to the roots. An increased amount of adhered bacteria was further confirmed by quantitative fluorescence measurements. The degree of infection by the fungus was measured and quantified by real-time-qPCR. Results showed that Titania nanoparticles increased adhesion of beneficial bacteria on to the roots of oilseed rape and protected the plants against infection.

Nano titania aided clustering and adhesion of beneficial bacteria to plant roots to enhance crop growth and stress management

NASA Astrophysics Data System (ADS)

Palmqvist, N. G. M.; Bejai, S.; Meijer, J.; Seisenbaeva, G. A.; Kessler, V. G.

2015-05-01

A novel use of Titania nanoparticles as agents in the nano interface interaction between a beneficial plant growth promoting bacterium (Bacillus amyloliquefaciens UCMB5113) and oilseed rape plants (Brassica napus) for protection against the fungal pathogen Alternaria brassicae is presented. Two different TiO2 nanoparticle material were produced by the Sol-Gel approach, one using the patented Captigel method and the other one applying TiBALDH precursor. The particles were characterized by transmission electron microscopy, thermogravimetric analysis, X-ray diffraction, dynamic light scattering and nano particle tracking analysis. Scanning electron microscopy showed that the bacterium was living in clusters on the roots and the combined energy-dispersive X-ray spectroscopy analysis revealed that titanium was present in these cluster formations. Confocal laser scanning microscopy further demonstrated an increased bacterial colonization of Arabidopsis thaliana roots and a semi-quantitative microscopic assay confirmed an increased bacterial adhesion to the roots. An increased amount of adhered bacteria was further confirmed by quantitative fluorescence measurements. The degree of infection by the fungus was measured and quantified by real-time-qPCR. Results showed that Titania nanoparticles increased adhesion of beneficial bacteria on to the roots of oilseed rape and protected the plants against infection.

A novel mineral flotation process using Thiobacillus ferrooxidans.

PubMed

Nagaoka, T; Ohmura, N; Saiki, H

1999-08-01

Oxidative leaching of metals by Thiobacillus ferrooxidans has proven useful in mineral processing. Here, we report on a new use for T. ferrooxidans, in which bacterial adhesion is used to remove pyrite from mixtures of sulfide minerals during flotation. Under control conditions, the floatabilities of five sulfide minerals tested (pyrite, chalcocite, molybdenite, millerite, and galena) ranged from 90 to 99%. Upon addition of T. ferrooxidans, the floatability of pyrite was significantly suppressed to less than 20%. In contrast, addition of the bacterium had little effect on the floatabilities of the other minerals, even when they were present in relatively large quantities: their floatabilities remained in the range of 81 to 98%. T. ferrooxidans thus appears to selectively suppress pyrite floatability. As a consequence, 77 to 95% of pyrite was removed from mineral mixtures while 72 to 100% of nonpyrite sulfide minerals was recovered. The suppression of pyrite floatability was caused by bacterial adhesion to pyrite surfaces. When normalized to the mineral surface area, the number of cells adhering to pyrite was significantly larger than the number adhering to other minerals. These results suggest that flotation with T. ferrooxidans may provide a novel approach to mineral processing in which the biological functions involved in cell adhesion play a key role in the separation of minerals.

A Novel Mineral Flotation Process Using Thiobacillus ferrooxidans

PubMed Central

Nagaoka, Toru; Ohmura, Naoya; Saiki, Hiroshi

1999-01-01

Oxidative leaching of metals by Thiobacillus ferrooxidans has proven useful in mineral processing. Here, we report on a new use for T. ferrooxidans, in which bacterial adhesion is used to remove pyrite from mixtures of sulfide minerals during flotation. Under control conditions, the floatabilities of five sulfide minerals tested (pyrite, chalcocite, molybdenite, millerite, and galena) ranged from 90 to 99%. Upon addition of T. ferrooxidans, the floatability of pyrite was significantly suppressed to less than 20%. In contrast, addition of the bacterium had little effect on the floatabilities of the other minerals, even when they were present in relatively large quantities: their floatabilities remained in the range of 81 to 98%. T. ferrooxidans thus appears to selectively suppress pyrite floatability. As a consequence, 77 to 95% of pyrite was removed from mineral mixtures while 72 to 100% of nonpyrite sulfide minerals was recovered. The suppression of pyrite floatability was caused by bacterial adhesion to pyrite surfaces. When normalized to the mineral surface area, the number of cells adhering to pyrite was significantly larger than the number adhering to other minerals. These results suggest that flotation with T. ferrooxidans may provide a novel approach to mineral processing in which the biological functions involved in cell adhesion play a key role in the separation of minerals. PMID:10427053

Nano titania aided clustering and adhesion of beneficial bacteria to plant roots to enhance crop growth and stress management

PubMed Central

Palmqvist, N. G. M.; Bejai, S.; Meijer, J.; Seisenbaeva, G. A.; Kessler, V. G.

2015-01-01

A novel use of Titania nanoparticles as agents in the nano interface interaction between a beneficial plant growth promoting bacterium (Bacillus amyloliquefaciens UCMB5113) and oilseed rape plants (Brassica napus) for protection against the fungal pathogen Alternaria brassicae is presented. Two different TiO2 nanoparticle material were produced by the Sol-Gel approach, one using the patented Captigel method and the other one applying TiBALDH precursor. The particles were characterized by transmission electron microscopy, thermogravimetric analysis, X-ray diffraction, dynamic light scattering and nano particle tracking analysis. Scanning electron microscopy showed that the bacterium was living in clusters on the roots and the combined energy-dispersive X-ray spectroscopy analysis revealed that titanium was present in these cluster formations. Confocal laser scanning microscopy further demonstrated an increased bacterial colonization of Arabidopsis thaliana roots and a semi-quantitative microscopic assay confirmed an increased bacterial adhesion to the roots. An increased amount of adhered bacteria was further confirmed by quantitative fluorescence measurements. The degree of infection by the fungus was measured and quantified by real-time-qPCR. Results showed that Titania nanoparticles increased adhesion of beneficial bacteria on to the roots of oilseed rape and protected the plants against infection. PMID:25970693

The characteristics of bacterial nanocellulose gel releasing silk sericin for facial treatment.

PubMed

Aramwit, Pornanong; Bang, Nipaporn

2014-12-09

Recently, naturally derived facial masks with beneficial biological properties have received increasing interest. In this study, silk sericin-releasing bacterial nanocellulose gel was developed to be applied as a bioactive mask for facial treatment. The silk sericin-releasing bacterial nanocellulose gel produced at a pH of 4.5 had an ultrafine and extremely pure fiber network structure. The mechanical properties and moisture absorption ability of the gel were improved, compared to those of the commercially available paper mask. Silk sericin could be control-released from the gel. A peel test with porcine skin showed that the gel was less adhesive than the commercially available paper mask, which would be removed from the face more easily without pain. The in vitro cytotoxicity test showed that the gel was not toxic to L929 mouse fibroblast and HaCaT human keratinocyte cells. Furthermore, when implanted subcutaneously and evaluated according to ISO10993-6 standard, the gel was not irritant to tissue. The silk sericin-releasing bacterial nanocellulose gel had appropriate physical and biological properties and safety for the facial treatment application.

[Effect of penicillin and the habitat medium in the body of bacterial carriers on the intercellular bonds in populations of the meningococcus and pertussis microbe].

PubMed

Vysotskiĭ, V V; Smirnova-Mutusheva, M A; Efimova, O G; Bakulina, N A

1983-04-01

The relationship of the bacterial cells in populations and their adhesion activity is at present one of the research priorities in microbiological studies. The stimulating effect of penicillin on the development of morphologically different intercellular bonds (IB) in populations of the pertussis causative agent and first of all derivatives or evaginates of the cell wall membranes was observed. Morphologically similar systems and polytubular IB were detected in populations of meningococcal strains isolated from carriers having no signs of the disease. Correlation between the after-effect of penicillin and the presence of the causative agent in bacterial carriers was shown. Unknown systems of interlacing tubular structures not directly bound with the cells, the walls of which were single contour membranes were determined in the meningococcal populations treated with penicillin. IB were observed in the population in the form of transpopulation cords. Morphologically different IB playing the role of specialized organelles might be considered as factors of the functional unity of the bacterial population as a multicellular system.

Reduced bacteria adhesion on octenidine loaded mesoporous silica nanoparticles coating on titanium substrates.

PubMed

Xu, Gaoqiang; Shen, Xinkun; Dai, Liangliang; Ran, Qichun; Ma, Pingping; Cai, Kaiyong

2017-01-01

Bacterial infection is one of the most severe postoperative complications leading to implantation failure. The early bacterial stage (4-6h) was proved to be the "decisive period" for long-term bacteria-related infection. Thus, to endow potential early antibacterial capacity for a titanium (Ti) based implant, an effective antiseptic agent of octenidine dihydrochloride (OCT) was effectively loaded on the mesoporous silica nanoparticles (MSNs)-incorporated titania coating which was fabricated by an electrophoretic-enhanced micro-arc oxidation technique. The surface characteristic of the coatings were characterized by various methods (SEM, AFM, XPS, XRD, etc.), and its corrosion resistance was also examined by the potentiodynamic polarization curves. The composite coating without OCT loading not only displayed good cytocompatibility but also exhibited certain anti-bacterial property. After loading with OCT, its antibacterial efficiency of the titanium substrates with composite coating was greatly enhanced without compromising their cytocompatibility. The study provides an approach for the fabrication of anti-bacterial Ti implant for potential orthopedic application. Copyright © 2016 Elsevier B.V. All rights reserved.

New bioactive and biobased product applications of pectin

USDA-ARS?s Scientific Manuscript database

Pectin is well known for its bioactive health-promoting properties and use in biobased products. Recent reports have demonstrated that pectin and pectic fractions have potential as prebiotics, prevent pathogenic bacterial adhesion, increase prostate specific antigen doubling time in patients with re...

MOLECULAR DETERMINANTS OF BACTERIAL ADHESION MONITORED BY ATOMIC FORCE MICROSCOPY (R821268)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Reduction of bacterial adhesion on dental composite resins by silicon-oxygen thin film coatings.

PubMed

Mandracci, Pietro; Mussano, Federico; Ceruti, Paola; Pirri, Candido F; Carossa, Stefano

2015-01-29

Adhesion of bacteria on dental materials can be reduced by modifying the physical and chemical characteristics of their surfaces, either through the application of specific surface treatments or by the deposition of thin film coatings. Since this approach does not rely on the use of drugs or antimicrobial agents embedded in the materials, its duration is not limited by their possible depletion. Moreover it avoids the risks related to possible cytotoxic effects elicited by antibacterial substances released from the surface and diffused in the surrounding tissues. In this work, the adhesion of Streptococcus mutans and Streptococcus mitis was studied on four composite resins, commonly used for manufacturing dental prostheses. The surfaces of dental materials were modified through the deposition of a-SiO(x) thin films by plasma enhanced chemical vapor deposition. The chemical bonding structure of the coatings was analyzed by Fourier-transform infrared spectroscopy. The morphology of the dental materials before and after the coating deposition was assessed by means of optical microscopy and high-resolution mechanical profilometry, while their wettability was investigated by contact angle measurements. The sample roughness was not altered after coating deposition, while a noticeable increase of wettability was detected for all the samples. Also, the adhesion of S. mitis decreased in a statistically significant way on the coated samples, when compared to the uncoated ones, which did not occur for S. mutans. Within the limitations of this study, a-SiO(x) coatings may affect the adhesion of bacteria such as S. mitis, possibly by changing the wettability of the composite resins investigated.

Antibacterial effect and shear bond strength of an orthodontic adhesive cement containing Galla chinensis extract

PubMed Central

WANG, LU-FEI; LUO, FENG; XUE, CHAO-RAN; DENG, MENG; CHEN, CHEN; WU, HAO

2016-01-01

Galla chinensis extract (GCE), a naturally-derived agent, has a significant inhibitory effect on cariogenic bacteria. The present study aims to evaluate the antibacterial effect and shear bond strength of an orthodontic adhesive cement containing GCE. A resin-modified glass ionomer cement incorporated GCE at five mass fractions (0, 0.1, 0.2, 0.4, and 0.8%) to prepare GCE-containing cement for analysis. For the agar diffusion test, cement specimens were placed on agar disk inoculated with Streptococcus mutans (strain ATCC 25175). Following 48 h incubation, the inhibition halo diameter was measured. To assess bacteria colonization susceptibility, S. mutans adhesion to cement specimens was detected by scanning electron microscopy (SEM) following 48 h incubation. To evaluate bond strength, a total of 50 metal brackets were bonded on premolar surfaces by using cement (10 teeth/group). Following immersion in an artificial saliva for 3 days, shear bond strength (SBS) was measured. The results demonstrated that GCE-containing samples exhibited a larger bacterial inhibition halo than control, and the inhibition zone increased as the GCE mass fraction increased. SEM analysis demonstrated that S. mutans presented a weaker adherent capacity to all GCE-containing cements compared with control, but the difference between each GCE-containing group was not significant. SBS values of each GCE-containing group exhibited no difference compared with the control. In conclusion, GCE-containing adhesive cement exhibits a promising inhibitory effect on S. mutans growth and adhesion. Without compromising bond strength, adding GCE in adhesive cement may be an attractive option for preventing white spot lesions during orthodontic treatment. PMID:27073642

The effect of a probiotic strain (Lactobacillus acidophilus) on the plaque formation of oral Streptococci.

PubMed

Tahmourespour, Arezoo; Kermanshahi, Rooha Kasra

2011-02-01

The objective of this study was to investigate the ability of biofilm formation among mutans and non mutans oral streptococci and to determine the effect of Lactobacillus acidophilus DSM 20079 as a probiotic strain on the adhesion of selected streptococcal strains on the surfaces. The sample comprised 40 isolates of oral streptococci from dental plaque and caries of volunteer persons. Streptococcus mutans ATCC35668 (no24) was as an standard strain. The probiotic strain was Lactobacillus acidophilus DSM 20079. The ability of biofilm formation was investigated with colorimetric method and the strongest isolates were selected. Then the effect of probiotic strain on the adhesion of streptococci isolates was determined in polystyrene microtiter plate simultaneously and 30 minutes before streptococci entrance to the system. The results showed that 42% of mutans streptococci were strongly adherent (SA) and in non mutans streptococci, only 23.5% of isolates were found strongly adherent. The strong biofilm forming bacterium isolated was Streptococcus mutans strain22. In the next step, in the presence of probiotic strain the streptococcal adhesion were reduced, and this reduction was non significantly stronger if the probiotic strain was inoculated to the system before the oral bacteria. The Lactobacillus acidophilus had more effect on adherence of mutans streptococci than non mutans streptococci with significant difference (p < 0.05). Adhesion reduction is likely due to bacterial interactions and colonization of adhesion sites with probiotic strain before the presence of streptococci. Adhesion reduction can be an effective way on decreasing cariogenic potential of oral streptococci.

[Influence of electromagnetic emission at the frequencies of molecular absorption and emission spectra of oxygen and nitrogen oxide on the adhesion and formation of Pseudomonas aeruginosa biofilm].

PubMed

Pronina, E A; Shvidenko, I G; Shub, G M; Shapoval, O G

2011-01-01

Evaluate the influence of electromagnetic emission (EME) at the frequencies of molecular absorption and emission spectra of atmospheric oxygen and nitrogen oxide (MAES 02 and MAES NO respectively) on the adhesion, population progress and biofilm formation of Pseudomonas aeruginosa. Adhesive activity was evaluated by mean adhesion index (MAI) of bacteria on human erythrocytes. Population growth dynamic was assessed by optical density index of broth cultures; biofilm formation--by values of optical density of the cells attached to the surface of polystyrol wells. P.aeruginosa bacteria had high adhesive properties that have increased under the influence of MAES 02 frequency emission and have not changed under the influence of MAES NO frequency. Exposure of bacteria to MAES NO frequency did not influence the population progress; exposure to MAES 02 frequency stimulated the biofilm formation ability of the bacteria, and MAES NO--decreased this ability. EME at MAES NO frequency can be used to suppress bacterial biofilm formation by pseudomonas.

Caffeic acid phenethyl ester suppresses monocyte adhesion to the endothelium by inhibiting NF-κB/NOX2-derived ROS signaling

PubMed Central

Nakahara, Risa; Makino, Junya; Kamiya, Tetsuro; Hara, Hirokazu; Adachi, Tetsuo

2016-01-01

Caffeic acid phenethyl ester (CAPE), one of the major polyphenols, exhibits anti-oxidative, anti-bacterial, and anti-cancer properties. Atherosclerosis is a chronic inflammatory disease, the progression of which is closely related to the accumulated adhesion of inflammatory monocytes/macrophages to the endothelium. We herein determined whether CAPE and its derivatives suppressed THP-1 cell adhesion to human umbilical vein endothelial cells (HUVEC). Of the four polyphenols tested, CAPE significantly suppressed the 12-O-tetradecanoylphorbol 13-acetate (TPA)-elicited expression of cluster for differentiation (CD) 11b, 14, and 36, and this was accompanied by the inhibition of THP-1 cell adhesion to HUVEC. CAPE also suppressed the activation of TPA-elicited nuclear factor-κB (NF-κB) and accumulation of NADPH oxidase 2 (NOX2)-derived reactive oxygen species (ROS), but did not affect extracellular signal-regulated kinase (ERK) phosphorylation. Taken together, these results demonstrated that CAPE suppressed THP-1 cell adhesion to HUVEC through, at least in part, the NF-κB, NOX2, and ROS-derived signaling axis. PMID:27257341

Preparing high-adhesion silver coating on APTMS modified polyethylene with excellent anti-bacterial performance

NASA Astrophysics Data System (ADS)

Li, Wenfei; Chen, Yunxiang; Wu, Song; Zhang, Jian; Wang, Hao; Zeng, Dawen; Xie, Changsheng

2018-04-01

Silver coating as a broad-spectrum antimicrobial agent was considered to alleviate the inflammation caused by intrauterine device (IUD) in endometrium. In this work, to avoid the damage of silver coating and ensure its antibacterial properties, 3-aminopropyltrimethoxysilane (APTMS) was introduced to modify the polyethylene (PE) substrate for the purpose of improving the adhesion of the silver coating. From the 90° peel test, it could be found that the adhesive strength of silver coating on the APTMS modified PE substrate was nearly 23 times stronger than the silver coating on substrate without surface modification. The dramatically enhanced adhesive strength could be attributed to the formation of continuous chemical bonds between the silver coatings and substrates after surface modification, which had been confirmed by the XPS. Moreover, the standard antibacterial test revealed that the silver coated samples against Staphylococcus aureus (S. aureus) exhibit excellent antibacterial efficacy. Considering the largely enhanced adhesion and the effective antibacterial property, it is reasonable to believe that the silver coating could be considered as a potential candidate for the antibacterial agent in IUD.

Uropathogenic E. coli Exploit CEA to Promote Colonization of the Urogenital Tract Mucosa

PubMed Central

Muenzner, Petra; Kengmo Tchoupa, Arnaud; Klauser, Benedikt; Brunner, Thomas; Putze, Johannes; Dobrindt, Ulrich; Hauck, Christof R.

2016-01-01

Attachment to the host mucosa is a key step in bacterial pathogenesis. On the apical surface of epithelial cells, members of the human carcinoembryonic antigen (CEA) family are abundant glycoproteins involved in cell-cell adhesion and modulation of cell signaling. Interestingly, several gram-negative bacterial pathogens target these receptors by specialized adhesins. The prototype of a CEACAM-binding pathogen, Neisseria gonorrhoeae, utilizes colony opacity associated (Opa) proteins to engage CEA, as well as the CEA-related cell adhesion molecules CEACAM1 and CEACAM6 on human epithelial cells. By heterologous expression of neisserial Opa proteins in non-pathogenic E. coli we find that the Opa protein-CEA interaction is sufficient to alter gene expression, to increase integrin activity and to promote matrix adhesion of infected cervical carcinoma cells and immortalized vaginal epithelial cells in vitro. These CEA-triggered events translate in suppression of exfoliation and improved colonization of the urogenital tract by Opa protein-expressing E. coli in CEA-transgenic compared to wildtype mice. Interestingly, uropathogenic E. coli expressing an unrelated CEACAM-binding protein of the Afa/Dr adhesin family recapitulate the in vitro and in vivo phenotype. In contrast, an isogenic strain lacking the CEACAM-binding adhesin shows reduced colonization and does not suppress epithelial exfoliation. These results demonstrate that engagement of human CEACAMs by distinct bacterial adhesins is sufficient to blunt exfoliation and to promote host infection. Our findings provide novel insight into mucosal colonization by a common UPEC pathotype and help to explain why human CEACAMs are a preferred epithelial target structure for diverse gram-negative bacteria to establish a foothold on the human mucosa. PMID:27171273

Force-Induced Strengthening of the Interaction between Staphylococcus aureus Clumping Factor B and Loricrin

PubMed Central

Vitry, Pauline; Valotteau, Claire; Feuillie, Cécile; Bernard, Simon

2017-01-01

ABSTRACT Bacterial pathogens that colonize host surfaces are subjected to physical stresses such as fluid flow and cell surface contacts. How bacteria respond to such mechanical cues is an important yet poorly understood issue. Staphylococcus aureus uses a repertoire of surface proteins to resist shear stress during the colonization of host tissues, but whether their adhesive functions can be modulated by physical forces is not known. Here, we show that the interaction of S. aureus clumping factor B (ClfB) with the squamous epithelial cell envelope protein loricrin is enhanced by mechanical force. We find that ClfB mediates S. aureus adhesion to loricrin through weak and strong molecular interactions both in a laboratory strain and in a clinical isolate. Strong forces (~1,500 pN), among the strongest measured for a receptor-ligand bond, are consistent with a high-affinity “dock, lock, and latch” binding mechanism involving dynamic conformational changes in the adhesin. Notably, we demonstrate that the strength of the ClfB-loricrin bond increases as mechanical force is applied. These findings favor a two-state model whereby bacterial adhesion to loricrin is enhanced through force-induced conformational changes in the ClfB molecule, from a weakly binding folded state to a strongly binding extended state. This force-sensitive mechanism may provide S. aureus with a means to finely tune its adhesive properties during the colonization of host surfaces, helping cells to attach firmly under high shear stress and to detach and spread under low shear stress. PMID:29208742

In vitro colonization of the muscle extracellular matrix components by Escherichia coli O157:H7: the influence of growth medium, temperature and pH on initial adhesion and induction of biofilm formation by collagens I and III.

PubMed

Chagnot, Caroline; Agus, Allison; Renier, Sandra; Peyrin, Frédéric; Talon, Régine; Astruc, Thierry; Desvaux, Mickaël

2013-01-01

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 are responsible for repeated food-poisoning cases often caused by contaminated burgers. EHEC infection is predominantly a pediatric illness, which can lead to life-threatening diseases. Ruminants are the main natural reservoir for EHEC and food contamination almost always originates from faecal contamination. In beef meat products, primary bacterial contamination occurs at the dehiding stage of slaughtering. The extracellular matrix (ECM) is the most exposed part of the skeletal muscles in beef carcasses. Investigating the adhesion to the main muscle fibrous ECM proteins, insoluble fibronectin, collagen I, III and IV, laminin-α2 and elastin, results demonstrated that the preceding growth conditions had a great influence on subsequent bacterial attachment. In the tested experimental conditions, maximal adhesion to fibril-forming collagens I or III occurred at 25°C and pH 7. Once initially adhered, exposure to lower temperatures, as applied to meat during cutting and storage, or acidification, as in the course of post-mortem physiological modifications of muscle, had no effect on detachment, except at pHu. In addition, dense biofilm formation occurred on immobilized collagen I or III and was induced in growth medium supplemented with collagen I in solution. From this first comprehensive investigation of EHEC adhesion to ECM proteins with respect to muscle biology and meat processing, new research directions for the development of innovative practices to minimize the risk of meat contamination are further discussed.

Electron microscopy, histochemistry, and microbiology of bacterial adhesion in trichomycosis axillaris.

PubMed

Shelley, W B; Miller, M A

1984-06-01

Study of a case of trichomycosis axillaris by electron microscopy revealed a specific encapsulated Corynebacterium adhering to but not penetrating the hair shaft. External to this were two other biochemically distinctive pleomorphic Corynebacteria shown to be incapable of direct adherence to the hair. All three types were entrapped in a virtually insoluble cement substance, which they elaborate and which is responsible for the grossly visible colonization that is so characteristic of this disease.

Fish skin bacteria: Colonial and cellular hydrophobicity.

PubMed

Sar, N; Rosenberg, E

1987-05-01

Bacteria were desorbed from the skin of healthy, fast-swimming fish by several procedures, including brief exposure to sonic oscillation and treatment with nontoxic surface active agents. The surface properties of these bacteria were studied by measuring their adhesion to hexadecane, as well as by a newly developed, simple method for studying the hydrophobicity of bacterial lawns. This method, referred to as the "Direction of Spreading" (DOS) method, consists of recording the direction to which a water drop spreads when introduced at the border between bacterial lawns and other surfaces. Of the 13 fish skin isolates examined, two strains were as hydrophobic as polystyrene by the DOS method. Suspended cells of one of these strains adhered strongly to hexadecane (84%), whereas cells of the other strain adhered poorly (13%). Another strain which was almost as hydrophobic as polystyrene by the DOS method did not adhere to hexadecane at all. Similarly, lawns of three other strains were more hydrophobic than glass by the DOS method, but cell suspensions prepared from these colonies showed little or no adhesion to hexadecane. The high colonial but relatively low cellular hydrophobicity could be due to a hydrophobic slime that is removed during the suspension and washing procedures. The possibility that specific bacteria assist in fish locomotion by changing the surface properties of the fish skin and by producing drag-reducing polymers is discussed.

Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties

PubMed Central

Variola, Fabio; Zalzal, Sylvia Francis; Leduc, Annie; Barbeau, Jean; Nanci, Antonio

2014-01-01

Mesoporous surfaces generated by oxidative nanopatterning have the capacity to selectively regulate cell behavior, but their impact on microorganisms has not yet been explored. The main objective of this study was to test the effects of such surfaces on the adherence of two common bacteria and one yeast strain that are responsible for nosocomial infections in clinical settings and biomedical applications. In addition, because surface characteristics are known to affect bacterial adhesion, we further characterized the physicochemical properties of the mesoporous surfaces. Focused ion beam (FIB) was used to generate ultrathin sections for elemental analysis by energy-dispersive X-ray spectroscopy (EDS), nanobeam electron diffraction (NBED), and high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) imaging. The adherence of Staphylococcus aureus, Escherichia coli and Candida albicans onto titanium disks with mesoporous and polished surfaces was compared. Disks with the two surfaces side-by-side were also used for direct visual comparison. Qualitative and quantitative results from this study indicate that bacterial adhesion is significantly hindered by the mesoporous surface. In addition, we provide evidence that it alters structural parameters of C. albicans that determine its invasiveness potential, suggesting that microorganisms can sense and respond to the mesoporous surface. Our findings demonstrate the efficiency of a simple chemical oxidative treatment in generating nanotextured surfaces with antimicrobial capacity with potential applications in the implant manufacturing industry and hospital setting. PMID:24872694

A novel point mutation in CD18 causing the expression of dysfunctional CD11/CD18 leucocyte integrins in a patient with leucocyte adhesion deficiency (LAD)

PubMed Central

Mathew, E C; Shaw, J M; Bonilla, F A; Law, S K A; Wright, D A

2000-01-01

Leucocyte adhesion deficiency type 1 (LAD-1) is characterized by the incapacity of leucocytes to carry out their adhesion functions via their CD11/CD18 antigens, which are also referred to as the leucocyte integrins. The patients generally suffer from poor wound healing and recurrent bacterial and fungal infections. In severe cases, the infections are often systemic and life-threatening. A LAD patient (AW) of moderate phenotype has been identified but, unlike most other cases, the level of CD11/CD18 antigens on her leucocytes are uncharacteristically high for a LAD patient. Molecular analysis revealed that she is a compound heterozygote for CD18 mutations. She has inherited a D231H mutation from her father and a G284S mutation from her mother. By transfection studies, it was established that the G284S mutation does not support CD11/CD18 antigen expression on the cell surface. In contrast, the D231H mutation does not affect CD18 forming integrin heterodimers with the CD11 antigens on the cell surface. However, the expressed integrins with the D231H mutation are not adhesive to ligands. PMID:10886250

Probiotics in Nonalcoholic Fatty Liver Disease, Nonalcoholic Steatohepatitis, and Cirrhosis.

PubMed

Qamar, Amir A

2015-01-01

With the growing epidemic of obesity, the incidence of both nonalcoholic fatty liver disease (NAFL) and nonalcoholic steatohepatitis (NASH) is increasing. The intestinal microbiota differs between individuals who are obese or have normal body mass indices. Animal studies have shown increased intestinal permeability in NAFL, NASH, and cirrhosis. This increases the risk of oxidative and inflammatory injury to the liver from intestinal microbacteria. It may also increase the risk of fatty acid injury and fatty deposition. Bacterial translocation is associated with increased portal hypertension and hepatic encephalopathy in cirrhosis. By preventing bacterial adhesion and translocation, probiotics may have a role in the management of patients with NAFL, NASH, and cirrhosis. Multiple small studies have suggested that probiotics improve some of the clinical markers of activity in patients with NAFL and NASH. Controlled studies have also shown improved outcomes in patients with cirrhosis who were treated with probiotics.

Studies on Magnetron Sputtered ZnO-Ag Films: Adhesion Activity of S. aureus

NASA Astrophysics Data System (ADS)

Geetha, S. R.; Dhivya, P.; Raj, P. Deepak; Sridharan, M.; Princy, S. Adline

Zinc oxide (ZnO) thin films have been deposited onto thoroughly cleaned stainless steel (AISI SS 304) substrates by reactive direct current (dc) magnetron sputtering and the films were doped with silver (Ag). The prepared thin films were analyzed using X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM) to investigate the structural and morphological properties. The thickness values of the films were in the range of 194 to 256nm. XRD results revealed that the films were crystalline with preferred (002) orientation. Grain size values of pure ZnO films were found to be 19.82-23.72nm. On introducing Ag into ZnO film, the micro-structural properties varied. Adhesion test was carried out with Staphylococcus aureus (S. aureus) in order to know the adherence property of the deposited films. Colony formation units (CFU) were counted manually and bacterial adhesion inhibition (BAI) was calculated. We observed a decrease in the CFU on doping Ag in the ZnO films. BAI of the film deposited at - 100 V substrate bias was found to be increased on Ag doping from 69 to 88%.

An Analytical Model for Determining Two-Dimensional Receptor-Ligand Kinetics

PubMed Central

Cheung, Luthur Siu-Lun; Konstantopoulos, Konstantinos

2011-01-01

Cell-cell adhesive interactions play a pivotal role in major pathophysiological vascular processes, such as inflammation, infection, thrombosis, and cancer metastasis, and are regulated by hemodynamic forces generated by blood flow. Cell adhesion is mediated by the binding of receptors to ligands, which are both anchored on two-dimensional (2-D) membranes of apposing cells. Biophysical assays have been developed to determine the unstressed (no-force) 2-D affinity but fail to disclose its dependence on force. Here we develop an analytical model to estimate the 2-D kinetics of diverse receptor-ligand pairs as a function of force, including antibody-antigen, vascular selectin-ligand, and bacterial adhesin-ligand interactions. The model can account for multiple bond interactions necessary to mediate adhesion and resist detachment amid high hemodynamic forces. Using this model, we provide a generalized biophysical interpretation of the counterintuitive force-induced stabilization of cell rolling observed by a select subset of receptor-ligand pairs with specific intrinsic kinetic properties. This study enables us to understand how single-molecule and multibond biophysics modulate the macroscopic cell behavior in diverse pathophysiological processes. PMID:21575567

Surface contact stimulates the just-in-time deployment of bacterial adhesins.

PubMed

Li, Guanglai; Brown, Pamela J B; Tang, Jay X; Xu, Jing; Quardokus, Ellen M; Fuqua, Clay; Brun, Yves V

2012-01-01

The attachment of bacteria to surfaces provides advantages such as increasing nutrient access and resistance to environmental stress. Attachment begins with a reversible phase, often mediated by surface structures such as flagella and pili, followed by a transition to irreversible attachment, typically mediated by polysaccharides. Here we show that the interplay between pili and flagellum rotation stimulates the rapid transition between reversible and polysaccharide-mediated irreversible attachment. We found that reversible attachment of Caulobacter crescentus cells is mediated by motile cells bearing pili and that their contact with a surface results in the rapid pili-dependent arrest of flagellum rotation and concurrent stimulation of polar holdfast adhesive polysaccharide. Similar stimulation of polar adhesin production by surface contact occurs in Asticcacaulis biprosthecum and Agrobacterium tumefaciens. Therefore, single bacterial cells respond to their initial contact with surfaces by triggering just-in-time adhesin production. This mechanism restricts stable attachment to intimate surface interactions, thereby maximizing surface attachment, discouraging non-productive self-adherence, and preventing curing of the adhesive. © 2011 Blackwell Publishing Ltd.

Putative outer membrane proteins of Leptospira interrogans stimulate human umbilical vein endothelial cells (HUVECS) and express during infection.

PubMed

Gómez, Ricardo M; Vieira, Monica L; Schattner, Mirta; Malaver, Elisa; Watanabe, Monica M; Barbosa, Angela S; Abreu, Patricia A E; de Morais, Zenaide M; Cifuente, Javier O; Atzingen, Marina V; Oliveira, Tatiane R; Vasconcellos, Silvio A; Nascimento, Ana L T O

2008-01-01

Cell adhesion molecules (CAMs) are surface receptors present in eukaryotic cells that mediate cell-cell or cell-extracellular matrix interactions. Vascular endothelium stimulation in vitro that lead to the upregulation of CAMs was reported for the pathogenic spirochaetes, including rLIC10365 of Leptospira interrogans. In this study, we report the cloning of LIC10507, LIC10508, LIC10509 genes of L. interrogans using Escherichia coli as a host system. The rational for selecting these sequences is due to their location in L. interrogans serovar Copenhageni genome that has a potential involvement in pathogenesis. The genes encode for predicted lipoproteins with no assigned functions. The purified recombinant proteins were capable to promote the upregulation of intercellular adhesion molecule 1 (ICAM-1) and E-selectin on monolayers of human umbilical vein endothelial cells (HUVECS). In addition, the coding sequences are expressed in the renal tubules of animal during bacterial experimental infection. The proteins are probably located at the outer membrane of the bacteria since they are detected in detergent-phase of L. interrogans Triton X-114 extract. Altogether our data suggest a possible involvement of these proteins during bacterial infection and provide new insights into the role of this region in the pathogenesis of Leptospira.

Enzyme-Linked Immunofiltration Assay To Estimate Attachment of Thiobacilli to Pyrite

PubMed Central

Dziurla, Marie-Antoinette; Achouak, Wafa; Lam, Bach-Tuyet; Heulin, Thierry; Berthelin, Jacques

1998-01-01

An enzyme-linked immunofiltration assay (ELIFA) has been developed in order to estimate directly and specifically Thiobacillus ferrooxidans attachment on sulfide minerals. This method derives from the enzyme-linked immunosorbent assay but is performed on filtration membranes which allow the retention of mineral particles for a subsequent immunoenzymatic reaction in microtiter plates. The polyclonal antiserum used in this study was raised against T. ferrooxidans DSM 583 and recognized cell surface antigens present on bacteria belonging to the genus Thiobacillus. This antiserum and the ELIFA allowed the direct quantification of attached bacteria with high sensitivity (104 bacteria were detected per well of the microtiter plate). The mean value of bacterial attachment has been estimated to be about 105 bacteria mg−1 of pyrite at a particle size of 56 to 65 μm. The geometric coverage ratio of pyrite by T. ferrooxidans ranged from 0.25 to 2.25%. This suggests an attachment of T. ferrooxidans on the pyrite surface to well-defined limited sites with specific electrochemical or surface properties. ELIFA was shown to be compatible with the measurement of variable levels of adhesion. Therefore, this method may be used to establish adhesion isotherms of T. ferrooxidans on various sulfide minerals exhibiting different physicochemical properties in order to understand the mechanisms of bacterial interaction with mineral surfaces. PMID:9687454

Sustained Nitric Oxide-Releasing Nanoparticles Interfere with Methicillin-Resistant Staphylococcus aureus Adhesion and Biofilm Formation in a Rat Central Venous Catheter Model

PubMed Central

Mihu, Mircea Radu; Cabral, Vitor; Pattabhi, Rodney; Tar, Moses T.; Davies, Kelvin P.; Friedman, Adam J.

2016-01-01

ABSTRACT Staphylococcus aureus is frequently isolated in the setting of infections of indwelling medical devices, which are mediated by the microbe's ability to form biofilms on a variety of surfaces. Biofilm-embedded bacteria are more resistant to antimicrobial agents than their planktonic counterparts and often cause chronic infections and sepsis, particularly in patients with prolonged hospitalizations. In this study, we demonstrate that sustained nitric oxide-releasing nanoparticles (NO-np) interfere with S. aureus adhesion and prevent biofilm formation on a rat central venous catheter (CVC) model of infection. Confocal and scanning electron microscopy showed that NO-np-treated staphylococcal biofilms displayed considerably reduced thicknesses and bacterial numbers compared to those of control biofilms in vitro and in vivo, respectively. Although both phenotypes, planktonic and biofilm-associated staphylococci, of multiple clinical strains were susceptible to NO-np, bacteria within biofilms were more resistant to killing than their planktonic counterparts. Furthermore, chitosan, a biopolymer found in the exoskeleton of crustaceans and structurally integrated into the nanoparticles, seems to add considerable antimicrobial activity to the technology. Our findings suggest promising development and translational potential of NO-np for use as a prophylactic or therapeutic against bacterial biofilms on CVCs and other medical devices. PMID:27821454

Sustained Nitric Oxide-Releasing Nanoparticles Interfere with Methicillin-Resistant Staphylococcus aureus Adhesion and Biofilm Formation in a Rat Central Venous Catheter Model.

PubMed

Mihu, Mircea Radu; Cabral, Vitor; Pattabhi, Rodney; Tar, Moses T; Davies, Kelvin P; Friedman, Adam J; Martinez, Luis R; Nosanchuk, Joshua D

2017-01-01

Staphylococcus aureus is frequently isolated in the setting of infections of indwelling medical devices, which are mediated by the microbe's ability to form biofilms on a variety of surfaces. Biofilm-embedded bacteria are more resistant to antimicrobial agents than their planktonic counterparts and often cause chronic infections and sepsis, particularly in patients with prolonged hospitalizations. In this study, we demonstrate that sustained nitric oxide-releasing nanoparticles (NO-np) interfere with S. aureus adhesion and prevent biofilm formation on a rat central venous catheter (CVC) model of infection. Confocal and scanning electron microscopy showed that NO-np-treated staphylococcal biofilms displayed considerably reduced thicknesses and bacterial numbers compared to those of control biofilms in vitro and in vivo, respectively. Although both phenotypes, planktonic and biofilm-associated staphylococci, of multiple clinical strains were susceptible to NO-np, bacteria within biofilms were more resistant to killing than their planktonic counterparts. Furthermore, chitosan, a biopolymer found in the exoskeleton of crustaceans and structurally integrated into the nanoparticles, seems to add considerable antimicrobial activity to the technology. Our findings suggest promising development and translational potential of NO-np for use as a prophylactic or therapeutic against bacterial biofilms on CVCs and other medical devices. Copyright © 2016 American Society for Microbiology.

Establishing Antibacterial Multilayer Films on the Surface of Direct Metal Laser Sintered Titanium Primed with Phase-Transited Lysozyme

PubMed Central

Guan, Binbin; Wang, Haorong; Xu, Ruiqing; Zheng, Guoying; Yang, Jie; Liu, Zihao; Cao, Man; Wu, Mingyao; Song, Jinhua; Li, Neng; Li, Ting; Cai, Qing; Yang, Xiaoping; Li, Yanqiu; Zhang, Xu

2016-01-01

Direct metal laser sintering is a technology that allows the fabrication of titanium (Ti) implants with a functional gradation of porosity and surface roughness according to three-dimensional (3D) computer data. The surface roughness of direct metal laser sintered titanium (DMLS-Ti) implants may provide abundant binding sites for bacteria. Bacterial colonization and subsequent biofilm formation can cause unsatisfactory cell adhesion and implant-related infections. To prevent such infections, a novel phase-transited lysozyme (PTL) was utilized as an initial functional layer to simply and effectively prime DMLS-Ti surfaces for subsequent coating with antibacterial multilayers. The purpose of the present study was to establish a surface with dual biological functionality. The minocycline-loaded polyelectrolyte multilayers of hyaluronic acid (HA) and chitosan (CS) formed via a layer-by-layer (LbL) self-assembly technique on PTL-functionalized DMLS-Ti were designed to inhibit pathogenic microbial infections while allowing the DMLS-Ti itself and the modified coatings to retain acceptable biocompatibility. The experimental results indicate that the DMLS-Ti and the hydrogel treated surfaces can inhibit early bacterial adhesion while completely preserving osteoblast functions. This design is expected to gain considerable interest in the medical field and to have good potential for applications in multifunctional DMLS-Ti implants. PMID:27821857

Establishing Antibacterial Multilayer Films on the Surface of Direct Metal Laser Sintered Titanium Primed with Phase-Transited Lysozyme.

PubMed

Guan, Binbin; Wang, Haorong; Xu, Ruiqing; Zheng, Guoying; Yang, Jie; Liu, Zihao; Cao, Man; Wu, Mingyao; Song, Jinhua; Li, Neng; Li, Ting; Cai, Qing; Yang, Xiaoping; Li, Yanqiu; Zhang, Xu

2016-11-08

Direct metal laser sintering is a technology that allows the fabrication of titanium (Ti) implants with a functional gradation of porosity and surface roughness according to three-dimensional (3D) computer data. The surface roughness of direct metal laser sintered titanium (DMLS-Ti) implants may provide abundant binding sites for bacteria. Bacterial colonization and subsequent biofilm formation can cause unsatisfactory cell adhesion and implant-related infections. To prevent such infections, a novel phase-transited lysozyme (PTL) was utilized as an initial functional layer to simply and effectively prime DMLS-Ti surfaces for subsequent coating with antibacterial multilayers. The purpose of the present study was to establish a surface with dual biological functionality. The minocycline-loaded polyelectrolyte multilayers of hyaluronic acid (HA) and chitosan (CS) formed via a layer-by-layer (LbL) self-assembly technique on PTL-functionalized DMLS-Ti were designed to inhibit pathogenic microbial infections while allowing the DMLS-Ti itself and the modified coatings to retain acceptable biocompatibility. The experimental results indicate that the DMLS-Ti and the hydrogel treated surfaces can inhibit early bacterial adhesion while completely preserving osteoblast functions. This design is expected to gain considerable interest in the medical field and to have good potential for applications in multifunctional DMLS-Ti implants.

Establishing Antibacterial Multilayer Films on the Surface of Direct Metal Laser Sintered Titanium Primed with Phase-Transited Lysozyme

NASA Astrophysics Data System (ADS)

Guan, Binbin; Wang, Haorong; Xu, Ruiqing; Zheng, Guoying; Yang, Jie; Liu, Zihao; Cao, Man; Wu, Mingyao; Song, Jinhua; Li, Neng; Li, Ting; Cai, Qing; Yang, Xiaoping; Li, Yanqiu; Zhang, Xu

2016-11-01

Direct metal laser sintering is a technology that allows the fabrication of titanium (Ti) implants with a functional gradation of porosity and surface roughness according to three-dimensional (3D) computer data. The surface roughness of direct metal laser sintered titanium (DMLS-Ti) implants may provide abundant binding sites for bacteria. Bacterial colonization and subsequent biofilm formation can cause unsatisfactory cell adhesion and implant-related infections. To prevent such infections, a novel phase-transited lysozyme (PTL) was utilized as an initial functional layer to simply and effectively prime DMLS-Ti surfaces for subsequent coating with antibacterial multilayers. The purpose of the present study was to establish a surface with dual biological functionality. The minocycline-loaded polyelectrolyte multilayers of hyaluronic acid (HA) and chitosan (CS) formed via a layer-by-layer (LbL) self-assembly technique on PTL-functionalized DMLS-Ti were designed to inhibit pathogenic microbial infections while allowing the DMLS-Ti itself and the modified coatings to retain acceptable biocompatibility. The experimental results indicate that the DMLS-Ti and the hydrogel treated surfaces can inhibit early bacterial adhesion while completely preserving osteoblast functions. This design is expected to gain considerable interest in the medical field and to have good potential for applications in multifunctional DMLS-Ti implants.

Anti-sessile bacterial and cytocompatibility properties of CHX-loaded nanohydroxyapatite.

PubMed

Barros, J; Grenho, L; Fernandes, M H; Manuel, C M; Melo, L F; Nunes, O C; Monteiro, F J; Ferraz, M P

2015-06-01

Nanohydroxyapatite possesses exceptional biocompatibility and bioactivity regarding bone cells and tissues, justifying its use as a coating material or as a bone substitute. Unfortunately, this feature may also encourage bacterial adhesion and biofilm formation. Surface functionalization with antimicrobials is a promising strategy to reduce the likelihood of bacterial infestation and colonization on medical devices. Chlorhexidine digluconate is a common and effective antimicrobial agent used for a wide range of medical applications. The purpose of this work was the development of a nanoHA biomaterial loaded with CHX to prevent surface bacterial accumulation and, simultaneously, with good cytocompatibility, for application in the medical field. CHX (5-1500 mg/L) was loaded onto nanoHA discs and the materials were evaluated for CHX adsorption and release profile, physic-chemical features, antibacterial activity against Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis, and cytocompatibility toward L929 fibroblasts. Results showed that the adsorption of CHX on nanoHA surface occurred by electrostatic interactions between the cationic group of CHX and the phosphate group of nanoHA. The release of CHX from CHX-loaded nanoHA showed a fast initial rate followed by a slower kinetics release, due to constraints caused by dilution and diffusion-limiting processes. NanoHA.50 to nanoHA.1500 showed strong anti-sessile activity, inhibiting bacterial adhesion and the biofilm formation. CHX-nanoHA caused a dose- and time-dependent inhibitory effect on the proliferation of fibroblasts for nanoHA.100 to nanoHA.1500. Cellular behavior on nanoHA.5 and nanoHA.50 was similar to control. Therefore, CHX-loaded nanoHA surfaces appear as a promising alternative to prevention of devices-related infections. Copyright © 2015 Elsevier B.V. All rights reserved.

Cross-kingdom interactions: Candida albicans and bacteria.

PubMed

Shirtliff, Mark E; Peters, Brian M; Jabra-Rizk, Mary Ann

2009-10-01

Bacteria and fungi are found together in a myriad of environments and particularly in a biofilm, where adherent species interact through diverse signaling mechanisms. Yet, despite billions of years of coexistence, the area of research exploring fungal-bacterial interactions, particularly within the context of polymicrobial infections, is still in its infancy. However, reports describing a multitude of wide-ranging interactions between the fungal pathogen Candida albicans and various bacterial pathogens are on the rise. An example of a mutually beneficial interaction is coaggregation, a phenomenon that takes place in oral biofilms where the adhesion of C. albicans to oral bacteria is considered crucial for its colonization of the oral cavity. In contrast, the interaction between C. albicans and Pseudomonas aeruginosa is described as being competitive and antagonistic in nature. Another intriguing interaction is that occurring between Staphylococcus aureus and C. albicans, which although not yet fully characterized, appears to be initially synergistic. These complex interactions between such diverse and important pathogens would have significant clinical implications if they occurred in an immunocompromised host. Therefore, understanding the mechanisms of adhesion and signaling involved in fungal-bacterial interactions may lead to the development of novel therapeutic strategies for impeding microbial colonization and development of polymicrobial disease. © 2009 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

The three-dimensional structure of CFA/I adhesion pili: traveler's diarrhea bacteria hang on by a spring.

PubMed

Mu, Xiang-Qi; Savarino, Stephen J; Bullitt, Esther

2008-02-22

To survive the harsh environment of a churning intestinal tract, bacteria attach to the host epithelium via thin fibers called pili (or fimbriae). Enterotoxigenic Escherichia coli bacteria expressing colonization factor antigen I (CFA/I) pili and related pili are the most common known bacterial cause of diarrheal disease, including traveler's diarrhea. CFA/I pili, assembled via the alternate chaperone pathway, are essential for binding and colonization of the small bowel by these pathogenic bacteria. Herein, we elucidate unique structural features of CFA/I pili that appear to optimize their function as bacterial tethers in the intestinal tract. Using transmission electron microscopy of negatively stained samples in combination with iterative three-dimensional helical reconstruction methods for image processing, we determined the structure of the CFA/I pilus filament. Our results indicate that strong end-to-end protein interactions and weak interactions between the coils of a sturdy spring-like helix provide the combination of strength, stability, and flexibility required to sustain bacterial adhesion and incite intestinal disease. We propose that CFA/I pili behave like a spring to maintain attachment to the gut lining during vortex mixing and downward flow of the intestinal contents, thereby persisting long enough for these bacteria to colonize the host epithelium and cause enteric disease.

Effects of titania nanotubes with or without bovine serum albumin loaded on human gingival fibroblasts

PubMed Central

Liu, Xiangning; Zhou, Xiaosong; Li, Shaobing; Lai, Renfa; Zhou, Zhiying; Zhang, Ye; Zhou, Lei

2014-01-01

Modifying the surface of the transmucosal area is a key research area because this process positively affects the three functions of implants: attachment to soft tissue, inhibiting bacterial biofilm adhesion, and the preservation of the crestal bone. To exploit the potential of titania nanotube arrays (TNTs) with or without using bovine serum albumin (BSA) to modify the surface of a dental implant in contact with the transmucosal area, BSA was loaded into TNTs that were fabricated by anodizing Ti sheets; the physical characteristics of these arrays, including their morphology, chemical composition, surface roughness, contact angle, and surface free energy (SFE), were assessed. The effect of Ti surfaces with TNTs or TNTs-BSA on human gingival fibroblasts (HGFs) was determined by analyzing cell morphology, early adhesion, proliferation, type I collagen (COL-1) gene expression, and the extracellular secretion of COL-1. The results indicate that early HGF adhesion and spreading behavior is positively correlated with surface characteristics, including hydrophilicity, SFE, and surface roughness. Additionally, TNT surfaces not only promoted early HGF adhesion, but also promoted COL-1 secretion. BSA-loaded TNT surfaces promoted early HGF adhesion, while suppressing late proliferation and COL-1 secretion. Therefore, TNT-modified smooth surfaces are expected to be applicable for uses involving the transmucosal area. Further study is required to determine whether BSA-loaded TNT surfaces actually affect closed loop formation of connective tissue because BSA coating actions in vivo are very rapid. PMID:24623977

Improved enrichment culture technique for methane-oxidizing bacteria from marine ecosystems: the effect of adhesion material and gas composition.

PubMed

Vekeman, Bram; Dumolin, Charles; De Vos, Paul; Heylen, Kim

2017-02-01

Cultivation of microbial representatives of specific functional guilds from environmental samples depends largely on the suitability of the applied growth conditions. Especially the cultivation of marine methanotrophs has received little attention, resulting in only a limited number of ex situ cultures available. In this study we investigated the effect of adhesion material and headspace composition on the methane oxidation activity in methanotrophic enrichments obtained from marine sediment. Addition of sterilized natural sediment or alternatively the addition of acid-washed silicon dioxide significantly increased methane oxidation. This positive effect was attributed to bacterial adhesion on the particles via extracellular compounds, with a minimum amount of particles required for effect. As a result, the particles were immobilized, thus creating a stratified environment in which a limited diffusive gas gradients could build up and various microniches were formed. Such diffusive gas gradient might necessitate high headspace concentrations of CH 4 and CO 2 for sufficient concentrations to reach the methane-oxidizing bacteria in the enrichment culture technique. Therefore, high concentrations of methane and carbon dioxide, in addition to the addition of adhesion material, were tested and indeed further stimulated methane oxidation. Use of adhesion material in combination with high concentrations of methane and carbon dioxide might thus facilitate the cultivation and subsequent enrichment of environmentally important members of this functional guild. The exact mechanism of the observed positive effects on methane oxidation and the differential effect on methanotrophic diversity still needs to be explored.

Antimicrobial Effect of Biocompatible Silicon Nanoparticles Activated Using Therapeutic Ultrasound.

PubMed

Shevchenko, Svetlana N; Burkhardt, Markus; Sheval, Eugene V; Natashina, Ulyana A; Grosse, Christina; Nikolaev, Alexander L; Gopin, Alexander V; Neugebauer, Ute; Kudryavtsev, Andrew A; Sivakov, Vladimir; Osminkina, Liubov A

2017-03-14

In this study, we report a method for the suppression of Escherichia coli (E. coli) vitality by means of therapeutic ultrasound irradiation (USI) using biocompatible silicon nanoparticles as cavitation sensitizers. Silicon nanoparticles without (SiNPs) and with polysaccharide (dextran) coating (DSiNPs) were used. Both types of nanoparticles were nontoxic to Hep 2 cells up to a concentration of 2 mg/mL. The treatment of bacteria with nanoparticles and application of 1 W/cm 2 USI resulted in the reduction of their viabilities up to 35 and 72% for SiNPs and DSiNPs, respectively. The higher bacterial viability reduction for DSiNPs as compared with SiNPs can be explained by the fact that the biopolymer shell of the polysaccharide provides a stronger adhesion of nanoparticles to the bacterial surface. Transmission electron microscopy (TEM) studies showed that the bacterial lipid shell was partially perforated after the combined treatment of DSiNPs and USI, which can be explained by the lysis of bacterial membrane due to the cavitation sensitized by the SiNPs. Furthermore, we have shown that 100% inhibition of E. coli bacterial colony growth is possible by coupling the treatments of DSiNPs and USI with an increased intensity of up to 3 W/cm 2 . The observed results reveal the application of SiNPs as promising antimicrobial agents.

Receptors, mediators, and mechanisms involved in bacterial sepsis and septic shock.

PubMed

Van Amersfoort, Edwin S; Van Berkel, Theo J C; Kuiper, Johan

2003-07-01

Bacterial sepsis and septic shock result from the overproduction of inflammatory mediators as a consequence of the interaction of the immune system with bacteria and bacterial wall constituents in the body. Bacterial cell wall constituents such as lipopolysaccharide, peptidoglycans, and lipoteichoic acid are particularly responsible for the deleterious effects of bacteria. These constituents interact in the body with a large number of proteins and receptors, and this interaction determines the eventual inflammatory effect of the compounds. Within the circulation bacterial constituents interact with proteins such as plasma lipoproteins and lipopolysaccharide binding protein. The interaction of the bacterial constituents with receptors on the surface of mononuclear cells is mainly responsible for the induction of proinflammatory mediators by the bacterial constituents. The role of individual receptors such as the toll-like receptors and CD14 in the induction of proinflammatory cytokines and adhesion molecules is discussed in detail. In addition, the roles of a number of other receptors that bind bacterial compounds such as scavenger receptors and their modulating role in inflammation are described. Finally, the therapies for the treatment of bacterial sepsis and septic shock are discussed in relation to the action of the aforementioned receptors and proteins.

Adhesion inhibition of F1C-fimbriated Escherichia coli and Pseudomonas aeruginosa PAK and PAO by multivalent carbohydrate ligands.

PubMed

Autar, Reshma; Khan, A Salam; Schad, Matthias; Hacker, Jörg; Liskamp, Rob M J; Pieters, Roland J

2003-12-05

In order to evaluate their inhibition of bacterial adhesion, the carbohydrate sequences GalNAcbeta1-->4Gal and GalNAcbeta1-->4Galbeta1-->4Glc were synthesized. The disaccharide was conjugated to dendrons based on the 3,5-di-(2-aminoethoxy)-benzoic acid branching unit to yield di- and tetravalent versions of these compounds. A divalent compound was also prepared that had significantly longer spacer arms. Relevant monovalent compounds were prepared for comparison. Their anti-adhesion properties against F1C-fimbriated uropathogenic Escherichia coli were evaluated in an ELISA-type assay by using a recombinant strain and also by using Pseudomonas aeruginosa strains PAO and PAK. Adhesion inhibition was observed in all cases, and multivalency effects of up to one order of magnitude were observed. The combination of spacer and multivalency effects led to a 38-fold increase in the potency of a divalent inhibitor with long spacer arms towards the PAO strain when compared with the free carbohydrate.

Durable bonds at the adhesive/dentin interface: an impossible mission or simply a moving target?

PubMed Central

SPENCER, Paulette; Jonggu PARK, Qiang YE; MISRA, Anil; BOHATY, Brenda S.; SINGH, Viraj; PARTHASARATHY, Ranga; SENE, Fábio; de Paiva GONÇALVES, Sérgio Eduardo; LAURENCE, Jennifer

2013-01-01

Composite restorations have higher failure rates, more recurrent caries and increased frequency of replacement as compared to dental amalgam. Penetration of bacterial enzymes, oral fluids, and bacteria into the crevices between the tooth and composite undermines the restoration and leads to recurrent decay and failure. The gingival margin of composite restora tions is particularly vulnerable to decay and at this margin, the adhesive and its seal to dentin provides the primary barrier between the prepared tooth and the environment. The intent of this article is to examine physico-chemical factors that affect the integrity and durability of the adhesive/dentin interfacial bond; and to explore how these factors act synergistically with mechanical forces to undermine the composite restoration. The article will examine the various avenues that have been pursued to address these problems and it will explore how alterations in material chemistry could address the detrimental impact of physico-chemical stresses on the bond formed at the adhesive/dentin interface. PMID:24855586

Immobilized liquid layers: A new approach to anti-adhesion surfaces for medical applications

PubMed Central

Sotiri, Irini; Overton, Jonathan C; Waterhouse, Anna

2016-01-01

Surface fouling and undesired adhesion are nearly ubiquitous problems in the medical field, complicating everything from surgeries to routine daily care of patients. Recently, the concept of immobilized liquid (IL) interfaces has been gaining attention as a highly versatile new approach to antifouling, with a wide variety of promising applications in medicine. Here, we review the general concepts behind IL layers and discuss the fabrication strategies on medically relevant materials developed so far. We also summarize the most important findings to date on applications of potential interest to the medical community, including the use of these surfaces as anti-thrombogenic and anti-bacterial materials, anti-adhesive textiles, high-performance coatings for optics, and as unique platforms for diagnostics. Although the full potential and pitfalls of IL layers in medicine are just beginning to be explored, we believe that this approach to anti-adhesive surfaces will prove broadly useful for medical applications in the future. PMID:27022136

Adherence of Aeromonas hydrophila strains to human enterocyte-like cells pre-infected with rotavirus.

PubMed

Bertuccio, M P; Picerno, I; Scoglio, M E

2012-09-01

The interest grown in these years about emerging pathogens in the onset of intestinal disease showed that the pathogenic mechanism is a multifactorial event. Our objective was to evaluate the role of co-infection with rotavirus in the expression of Aeromonas spp adhesiveness. The rate of co-infection involves contact of Caco-2 cells with the virus, followed by adsorption for 1 and 2 hours. Aliquots of bacterial suspensions were added to tissue-culture plates. After infection, cell monolayers were lysed; serially diluted lysates were plated to determine the number of bound bacteria by performing colony forming units (CFU) counts. Non-adhesive strains were not subject to variations resulting from co-infection, while those who had medium or high adhesiveness gave rise to an increase of the same. Infection with rotavirus promotes the Aeromonas ability to adhere to Caco-2 cells and this effect depends on the duration of infection and on the starting adhesiveness of bacteria strain.

Deletion of pilA, a Minor Pilin-Like Gene, from Xanthomonas citri subsp. citri Influences Bacterial Physiology and Pathogenesis.

PubMed

Petrocelli, Silvana; Arana, Maite R; Cabrini, Marcela N; Casabuono, Adriana C; Moyano, Laura; Beltramino, Matías; Moreira, Leandro M; Couto, Alicia S; Orellano, Elena G

2016-12-01

Type IV pili (Tfp) are widely distributed adhesins of bacterial surfaces. In plant pathogenic bacteria, Tfp are involved in host colonization and pathogenesis. Xanthomonas citri subsp. citri (Xcc) is the phytopathogen responsible for citrus canker disease. In this work, three Tfp structural genes, fimA, fimA1, and pilA from Xcc were studied. A pilA mutant strain from Xcc (XccΔpilA) was constructed and differences in physiological features, such as motilities, adhesion, and biofilm formation, were observed. A structural study of the purified Tfp fractions from Xcc wild-type and Xcc∆pilA showed that pilins are glycosylated in both strains and that FimA and FimA1 are the main structural components of the pili. Furthermore, smaller lesion symptoms and reduced bacterial growth were produced by Xcc∆pilA in orange plants compared to the wild-type strain. These results indicate that the minor pilin-like gene, pilA, is involved in Tfp performance during the infection process.

Influence of protein deposition on bacterial adhesion to contact lenses.

PubMed

Subbaraman, Lakshman N; Borazjani, Roya; Zhu, Hua; Zhao, Zhenjun; Jones, Lyndon; Willcox, Mark D P

2011-08-01

The aim of the study is to determine the adhesion of Gram positive and Gram negative bacteria onto conventional hydrogel (CH) and silicone hydrogel (SH) contact lens materials with and without lysozyme, lactoferrin, and albumin coating. Four lens types (three SH-balafilcon A, lotrafilcon B, and senofilcon A; one CH-etafilcon A) were coated with lysozyme, lactoferrin, or albumin (uncoated lenses acted as controls) and then incubated in Staphylococcus aureus (Saur 31) or either of two strains of Pseudomonas aeruginosa (Paer 6294 and 6206) for 24 h at 37 °C. The total counts of the adhered bacteria were determined using the H-thymidine method and viable counts by counting the number of colony-forming units on agar media. All three strains adhered significantly lower to uncoated etafilcon A lenses compared with uncoated SH lenses (p < 0.05). Lysozyme coating on all four lens types increased binding (total and viable counts) of Saur 31 (p < 0.05). However, lysozyme coating did not influence P. aeruginosa adhesion (p > 0.05). Lactoferrin coating on lenses increased binding (total and viable counts) of Saur 31 (p < 0.05). Lactoferrin-coated lenses showed significantly higher total counts (p < 0.05) but significantly lower viable counts (p < 0.05) of adhered P. aeruginosa strains. There was a significant difference between the total and viable counts (p < 0.05) that were bound to lactoferrin-coated lenses. Albumin coating of lenses increased binding (total and viable counts) of all three strains (p < 0.05). Lysozyme deposited on contact lenses does not possess antibacterial activity against certain bacterial strains, whereas lactoferrin possess an antibacterial effect against strains of P. aeruginosa.

A proteinaceous fraction of wheat bran may interfere in the attachment of enterotoxigenic E. coli K88 (F4+) to porcine epithelial cells.

PubMed

González-Ortiz, Gemma; Bronsoms, Sílvia; Quarles Van Ufford, H C; Halkes, S Bart A; Virkola, Ritva; Liskamp, Rob M J; Beukelman, Cees J; Pieters, Roland J; Pérez, José Francisco; Martín-Orúe, Susana María

2014-01-01

Wheat bran (WB) from Triticum aestivum has many beneficial effects on human health. To the best of our knowledge, very little has been published about its ability to prevent pathogenic bacterial adhesion in the intestine. Here, a WB extract was fractionated using different strategies, and the obtained fractions were tested in different in vitro methodologies to evaluate their interference in the attachment of enterotoxigenic Escherichia coli (ETEC) K88 to intestinal porcine epithelial cells (IPEC-J2) with the aim of identifying the putative anti-adhesive molecules. It was found that a proteinaceous compound in the >300-kDa fraction mediates the recognition of ETEC K88 to IPEC-J2. Further fractionation of the >300-kDa sample by size-exclusion chromatography showed several proteins below 90 kDa, suggesting that the target protein belongs to a high-molecular-weight (MW) multi-component protein complex. The identification of some relevant excised bands was performed by mass spectrometry (MS) and mostly revealed the presence of various protease inhibitors (PIs) of low MW: Serpin-Z2B, Class II chitinase, endogenous alpha-amylase/subtilisin inhibitor and alpha-amylase/trypsin inhibitor CM3. Furthermore, an incubation of the WB extract with ETEC K88 allowed for the identification of a 7S storage protein globulin of wheat, Globulin 3 of 66 kDa, which may be one of the most firmly attached WB proteins to ETEC K88 cells. Further studies should be performed to gain an understanding of the molecular recognition of the blocking process that takes place. All gathered information can eventually pave the way for the development of novel anti-adhesion therapeutic agents to prevent bacterial pathogenesis.

Flagellar Cap Protein FliD Mediates Adherence of Atypical Enteropathogenic Escherichia coli to Enterocyte Microvilli

PubMed Central

Sampaio, Suely C. F.; Luiz, Wilson B.; Vieira, Mônica A. M.; Ferreira, Rita C. C.; Garcia, Bruna G.; Sinigaglia-Coimbra, Rita; Sampaio, Jorge L. M.; Ferreira, Luís C. S.

2016-01-01

The expression of flagella correlates with different aspects of bacterial pathogenicity, ranging from adherence to host cells to activation of inflammatory responses by the innate immune system. In the present study, we investigated the role of flagella in the adherence of an atypical enteropathogenic Escherichia coli (aEPEC) strain (serotype O51:H40) to human enterocytes. Accordingly, isogenic mutants deficient in flagellin (FliC), the flagellar structural subunit; the flagellar cap protein (FliD); or the MotAB proteins, involved in the control of flagellar motion, were generated and tested for binding to differentiated Caco-2 cells. Binding of the aEPEC strain to enterocytes was significantly impaired in strains with the fliC and fliD genes deleted, both of which could not form flagella on the bacterial surface. A nonmotile but flagellated MotAB mutant also showed impaired adhesion to Caco-2 cells. In accordance with these observations, adhesion of aEPEC strain 1711-4 to Caco-2 cells was drastically reduced after the treatment of Caco-2 cells with purified FliD. In addition, incubation of aEPEC bacteria with specific anti-FliD serum impaired binding to Caco-2 cells. Finally, incubation of Caco-2 cells with purified FliD, followed by immunolabeling, showed that the protein was specifically bound to the microvillus tips of differentiated Caco-2 cells. The aEPEC FliD or anti-FliD serum also reduced the adherence of prototype typical enteropathogenic, enterohemorrhagic, and enterotoxigenic E. coli strains to Caco-2 cells. In conclusion, our findings further strengthened the role of flagella in the adherence of aEPEC to human enterocytes and disclosed the relevant structural and functional involvement of FliD in the adhesion process. PMID:26831466

The flagella of F18ab Escherichia coli is a virulence factor that contributes to infection in a IPEC-J2 cell model in vitro.

PubMed

Duan, Qiangde; Zhou, Mingxu; Zhu, Xiaofang; Bao, Wenbin; Wu, Shenglong; Ruan, Xiaosai; Zhang, Weiping; Yang, Yang; Zhu, Jun; Zhu, Guoqiang

2012-11-09

Bacterial flagella contribute to pathogen virulence; however, the role of flagella in the pathogenesis of F18ab E. coli-mediated swine edema disease (ED) is not currently known. We therefore evaluated the role of flagella in F18ab E. coli adhesion, invasion, biofilm formation, and IL-8 production using an in vitro cell infection model approach with gene-deletion mutant and complemented bacterial strains. We demonstrated that the flagellin-deficient fliC mutant had a marked decrease in the ability to adhere to and invade porcine epithelial IPEC-J2 cells. Surprisingly, there was no difference in adhesion between the F18 fimbriae-deficient ΔfedA mutant and its parent strain. In addition, both the ΔfedA and double ΔfliCΔfedA mutants exhibited an increased ability to invade IPEC-J2 cells compared to the wild-type strain, although this may be due to increased expression of other adhesins following the loss of F18ab fimbriae and flagella. Compared to the wild-type strain, the ΔfliC mutant showed significantly reduced ability to form biofilm, whereas the ΔfedA mutant increased biofilm formation. Although ΔfliC, ΔfedA, and ΔfliCΔfedA mutants had a reduced ability to stimulate IL-8 production from infected Caco-2 cells, the ΔfliC mutant impaired this ability to a greater extent than the ΔfedA mutant. The results from this study clearly demonstrate that flagella are required for efficient F18ab E. coli adhesion, invasion, biofilm formation, and IL-8 production in vitro. Copyright © 2012 Elsevier B.V. All rights reserved.

The influence of nanostructured features on bacterial adhesion and bone cell functions on severely shot peened 316L stainless steel.

PubMed

Bagherifard, Sara; Hickey, Daniel J; de Luca, Alba C; Malheiro, Vera N; Markaki, Athina E; Guagliano, Mario; Webster, Thomas J

2015-12-01

Substrate grain structure and topography play major roles in mediating cell and bacteria activities. Severe plastic deformation techniques, known as efficient metal-forming and grain refining processes, provide the treated material with novel mechanical properties and can be adopted to modify nanoscale surface characteristics, possibly affecting interactions with the biological environment. This in vitro study evaluates the capability of severe shot peening, based on severe plastic deformation, to modulate the interactions of nanocrystallized metallic biomaterials with cells and bacteria. The treated 316L stainless steel surfaces were first investigated in terms of surface topography, grain size, hardness, wettability and residual stresses. The effects of the induced surface modifications were then separately studied in terms of cell morphology, adhesion and proliferation of primary human osteoblasts (bone forming cells) as well as the adhesion of multiple bacteria strains, specifically Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and ampicillin-resistant Escherichia coli. The results indicated a significant enhancement in surface work hardening and compressive residual stresses, maintenance of osteoblast adhesion and proliferation as well as a remarkable decrease in the adhesion and growth of gram-positive bacteria (S. aureus and S. epidermidis) compared to non-treated and conventionally shot peened samples. Impressively, the decrease in bacteria adhesion and growth was achieved without the use of antibiotics, for which bacteria can develop a resistance towards anyway. By slightly grinding the surface of severe shot peened samples to remove differences in nanoscale surface roughness, the effects of varying substrate grain size were separated from those of varying surface roughness. The expression of vinculin focal adhesions from osteoblasts was found to be singularly and inversely related to grain size, whereas the attachment of gram-positive bacteria (S. aureus and S. epidermidis) decreased with increasing nanoscale surface roughness, and was not affected by grain refinement. Ultimately, this study demonstrated the advantages of the proposed shot peening treatment to produce multifunctional 316L stainless steel materials for improved implant functions without necessitating the use of drugs. Copyright © 2015 Elsevier Ltd. All rights reserved.

In vitro antibacterial activity of adhesive systems on Streptococcus mutans.

PubMed

Paradella, Thaís Cachuté; Koga-Ito, Cristiane Yumi; Jorge, Antonio Olavo Cardoso

2009-04-01

To evaluate the antibacterial activity of three adhesive systems -- Prime & Bond 2.1 (PB), Clearfil SE Bond (CS) and One Up Bond F (OU) -- on Streptococcus mutans in vitro. Adherence and agar disk-diffusion tests were performed. For the adherence testing, 40 human enamel specimens (4 mm2) were sterilized and the adhesive sytems were applied (n = 10). The control group did not receive the application of any adhesive system. Specimens were immersed in brain heart infusion broth (BHI) inoculated with S. mutans standardized suspension (10(6) cells/ml) for 48 h at 37 degrees C and 5% CO2. The number of S. mutans cells adhered to each specimen was evaluated by the plating method on BHI agar. For agar disk-diffusion testing, adhesive disks and disks soaked in distilled water (negative control) or 0.2% chlorexidine (positive control) were incubated with S. mutans for 48 h. The diameters of the zones of bacterial inhibition were measured. Adherence data were transformed in logarithms of base 10 (log10). Data were submitted to Kruskal-Wallis and Student-Neuman-Keuls tests at the 5% level of significance. The results of the adherence test showed that One Up Bond F (OU) and Clearfil SE Bond (CS) did not differ significantly from one another, but allowed significantly less adherence than Prime & Bond 2.1 (PB) and control [mean log10 (standard deviation) values: PB 6.10 (0.19); CS primer 4.55 (0.98); OU 4.65 (0.54); control group 6.34 (0.27)]. The disk-diffusion test showed no significant difference between OU (diameter in mm: 3.02 +/- 0.13) and CS (3.0 +/- 0.12), but both were significantly more effective in inhibiting bacterial growth than PB (1.0 +/- 0.10). The self-etching systems Clearfil SE Bond and One Up Bond F presented a greater inhibitory effect against S. mutans, also in terms of adherence, than did the conventional system, Prime & Bond 2.1.

Amended Description of the Genes for Synthesis of Actinomyces naeslundii T14V Type 1 Fimbriae and Associated Adhesin

DTIC Science & Technology

2007-05-07

type 2 fimbriae promote biofilm formation (14) through recognition of hostlike saccharide motifs in the surface polysaccharides of early colonizing...a NuPAGE Tris-acetate gradient gel (3 to 8%), transferred to a nitro- cellulose membrane, probed with MAb 8A against an epitope of FimP, and...inhibitors of bacterial adhesion: observations from the study of gram-positive bacteria that initiate biofilm formation on the tooth surface. Adv. Dent. Res

Atomic layer deposition of nano-TiO2 thin films with enhanced biocompatibility and antimicrobial activity for orthopedic implants

PubMed Central

Liu, Luting; Bhatia, Ritwik; Webster, Thomas J

2017-01-01

Titanium (Ti) and its alloys have been extensively used as implant materials in orthopedic applications. Nevertheless, implants may fail due to a lack of osseointegration and/or infection. The aim of this in vitro study was to endow an implant surface with favorable biological properties by the dual modification of surface chemistry and nanostructured topography. The application of a nanostructured titanium dioxide (TiO2) coating on Ti-based implants has been proposed as a potential way to enhance tissue-implant interactions while inhibiting bacterial colonization simultaneously due to its chemical stability, biocompatibility, and antimicrobial properties. In this paper, temperature-controlled atomic layer deposition (ALD) was introduced for the first time to provide unique nanostructured TiO2 coatings on Ti substrates. The effect of nano-TiO2 coatings with different morphology and structure on human osteoblast and fibroblast functions and bacterial activities was investigated. In vitro results indicated that the TiO2 coating stimulated osteoblast adhesion and proliferation while suppressing fibroblast adhesion and proliferation compared to uncoated materials. In addition, the introduction of nano-TiO2 coatings was shown to inhibit gram-positive bacteria (Staphylococcus aureus), gram-negative bacteria (Escherichia coli), and antibiotic-resistant bacteria (methicillin-resistant Staphylococcus aureus), all without resorting to the use of antibiotics. Our results suggest that the increase in nanoscale roughness and greater surface hydrophilicity (surface energy) together could contribute to increased protein adsorption selectively, which may affect the cellular and bacterial activities. It was found that ALD-grown TiO2-coated samples with a moderate surface energy at 38.79 mJ/m2 showed relatively promising antibacterial properties and desirable cellular functions. The ALD technique provides a novel and effective strategy to produce TiO2 coatings with delicate control of surface nanotopography and surface energy to enhance the interfacial biocompatibility and mitigate bacterial infection, and could potentially be used for improving numerous orthopedic implants. PMID:29263665

Mechanisms of Staphylococcus epidermidis adhesion to model biomaterial surfaces: Establising a link between thrombosis and infection

NASA Astrophysics Data System (ADS)

Higashi, Julie Miyo

Infections involving Staphylococcus epidermidis remain a life threatening complication associated with the use of polymer based cardiovascular devices. One of the critical steps in infection pathogenesis is the adhesion of the bacteria to the device surface. Currently, mechanisms of S. epidermidis adhesion are incompletely understood, but are thought to involve interactions between bacteria, device surface, and host blood elements in the form of adsorbed plasma proteins and surface adherent platelets. Our central hypothesis is that elements participating in thrombosis also promote S. epidermidis adhesion by specifically binding to the bacterial surface. The adhesion kinetics of S. epidermidis RP62A to host modified model biomaterial surface octadecyltrichlorosilane (OTS) under hydrodynamic shear conditions were characterized. Steady state adhesion to adsorbed proteins and surface adherent platelets was achieved at 90-120 minutes and 60-90 minutes, respectively. A dose response curve of S. epidermidis adhesion in the concentration range of 10sp7{-}10sp9 bac/mL resembled a multilayer adsorption isotherm. Increasing shear stress was found to LTA, and other LTA blocking agents significantly decreased S. epidermidis adhesion to the fibrin-platelet clots, suggesting that this interaction between S. epidermidis and fibrin-platelet clots is specific. Studies evaluated the adhesion of S. epidermidis to polymer immobilized heparin report conflicting results. Paulsson et al., showed that coagulase negative staphylococci adhered in comparable numbers to both immobilized heparin and nonheparinized surfaces, while exhibiting significantly greater adhesion to both surfaces than S. aureus. Preadsorption of the surfaces with specific heparin binding plasma proteins vitronectin, fibronectin, laminin, and collagen significantly increased adhesion. It was postulated that immobilized heparin contained binding sites for the plasma proteins, exposing bacteria binding domains of the protein. Aggregation of heparin coated (adsorbed) polystyrene beads by the same S. epidermidis strains did not correlate with the adherence assays on the immobilized heparin surfaces and staphylococcal binding was dependent on media ionic strength and pH, suggesting that the conformation of the heparin polysaccharide chains was crucial to the interaction (132). Another study by Arciola et al., showed that heparin modified PMMA intraocular lenses sustained significantly less adherent bacteria than unmodified PMMA lenses, and that the chromatogram of structural fatty acids of only the S. epidermidis adherent to heparin modified PMMA changed (133). Because neither of these investigators thoroughly characterized their heparin modified surfaces, the difference in their results could easily be explained by the notorious heterogeneity of the heparin molecular weight, bioactivity, or surface coverage on these polymers.

Amaranthus caudatus extract inhibits the invasion of E. coli into uroepithelial cells.

PubMed

Mohanty, Soumitra; Zambrana, Silvia; Dieulouard, Soizic; Kamolvit, Witchuda; Nilsén, Vera; Gonzales, Eduardo; Östenson, Claes-Göran; Brauner, Annelie

2018-06-28

Amaranthus caudatus is traditionally used to treat infections. Based on its traditional usage, we investigated the effect of A. caudatus on the bladder epithelial cells in the protection of E. coli infection. The direct antimicrobial effects of A. caudatus on uropathogenic bacteria were investigated using minimum inhibitory concentration (MIC) assay. Bladder epithelial cell lines T24 and 5637 and uropathogenic E. coli strain #12 were used to investigate the effect of A. caudatus. Bacterial adhesion and invasion into bladder cells treated with A. caudatus was analyzed. Expression of uroplakin-1a (UPK1A), β1 integrin (ITGB1), caveolin-1 (CAV1) and the antimicrobial peptides human β defensin-2 (DEFB4A) and LL-37 (CAMP) was evaluated using RT-PCR. No direct antibacterial effect on E. coli or any of the tested uropathogenic strains was observed by A. caudatus. However, we demonstrated reduced mRNA expression of uroplakin-1a and caveolin-1, but not β1 integrin after treatment of uroepithelial cells, mirrored by the decreased adhesion and invasion of E. coli. A. caudatus treatment did not induce increased gene expression of the antimicrobial peptides, LL-37 and human β-defensin-2. Our results showed that A. caudatus has a protective role on bladder epithelial cells against uropathogenic E. coli infection by decreasing the bacterial adhesion and invasion, thereby preventing infection. Copyright © 2018 Elsevier B.V. All rights reserved.

Invited review: Anti-adhesive properties of bovine oligosaccharides and bovine milk fat globule membrane-associated glycoconjugates against bacterial food enteropathogens.

PubMed

Douëllou, T; Montel, M C; Thevenot Sergentet, D

2017-05-01

The prevalence of the main raw milk and raw milk-derived dairy product enteropathogens (Campylobacter, Shiga toxin-producing Escherichia coli, Listeria, and Salmonella) is higher than the number of epidemiological cases related to ingesting these foodstuffs. Bovine milk oligosaccharides and milk fat globule membrane (MFGM)-linked glycoconjugates interact with foodborne enteropathogens to inhibit their adhesion to intestinal cells and tissues. This review examines the main mechanisms and strategies used by enteropathogens to adhere to their target, details the anti-adhesive properties of MFGM against enteropathogens and enterotoxins, assesses the integrity of bacteria-MFGM complexes during dairy product manufacture and digestion, and discusses the potential for using these macromolecules and glycoconjugates in foods for public health. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Consumption of apple-boysenberry beverage decreases salivary Actinomyces naeslundii and their adhesion in a multi-species biofilm model.

PubMed

Parkar, S G; Eady, S; Cabecinha, M; Skinner, M A

2017-04-26

We hypothesised that consumption of beverage rich in both fibre and polyphenols, rather than each bioactive alone, will modulate populations of selected salivary bacteria, and their adhesion characteristics and that some of these effects may be due to the anti-microbial activity of the beverage bioactives. We investigated the effect of 4 weeks' consumption of beverages, rich in apple fibre, boysenberry polyphenols, or both on salivary bacteria in healthy subjects. In this placebo-controlled crossover study, saliva samples were collected at the beginning and end of each treatment period, and used for qPCR quantitation of Lactobacillus spp., Actinomyces naeslundii and Streptococcus mutans. The counts of salivary A. naeslundii decreased after the consumption of the apple-boysenberry beverage (P<0.05, Student's t-test). We also examined the effect of the subjects' saliva on bacterial adhesion using a mixed species biofilm model. The salivary pellicles prepared before and after each treatment were inoculated with laboratory strains of A. naeslundii, Lactobacillus rhamnosus and S. mutans and tested for biofilm formation. The post appleboysenberry beverage salivary pellicle significantly decreased the adhesion of A. naeslundii at the end of both 3 and 24 h, in the in vitro biofilm. A 1/16 dilution of the apple-boysenberry beverage itself decreased the proliferation of test strains of A. naeslundii and S. mutans by 51 and 55%, respectively (P<0.005), indicating the antimicrobial activity of its bioactives. This study demonstrated that consumption of apple-boysenberry beverage, rather than apple or the boysenberry beverage alone or the placebo, decreased salivary A. naeslundii and their adhesion under laboratory conditions. These changes are factors that influence oral microecology and potentially oral health.

AFM probing in aqueous environment of Staphylococcus epidermidis cells naturally immobilised on glass: physico-chemistry behind the successful immobilisation.

PubMed

Méndez-Vilas, A; Gallardo-Moreno, A M; Calzado-Montero, R; González-Martín, M L

2008-05-01

AFM probing of microbial cells in liquid environments usually requires them to be physically or chemically attached to a solid surface. The fixation mechanisms may influence the nanomechanical characterization done by force curve mapping using an AFM. To study the response of a microbial cell surface to this kind of local measurement this study attempts to overcome the problem associated to the uncertainties introduced by the different fixation treatments by analysing the surface of Staphylococcus epidermidis cells naturally (non-artificially mediated) immobilised on a glass support surface. The particularities of this natural bacterial fixation process for AFM surface analysis are discussed in terms of theoretical predictions of the XDLVO model applied to the systems bacteria/support substratum and bacteria/AFM tip immersed in water. In this sense, in the first part of this study the conditions for adequate natural fixation of three S. epidermidis strains have been analyzed by taking into account the geometries of the bacterium, substrate and tip. In the second part, bacteria are probed without the risk of any possible artefacts due to the mechanical or chemical fixation procedures. Forces measured over the successfully adhered cells have (directly) shown that the untreated bacterial surface suffers from a combination of both reversible and non-reversible deformations during acquisition of force curves all taken under the same operational conditions. This is revealed directly through high-resolution tapping-mode imaging of the bacterial surface immediately following force curve mapping. The results agree with the two different types of force curves that were repeatedly obtained. Interestingly, one type of these force curves suggests that the AFM tip is breaking (rather than pushing) the cell surface during acquisition of the force curve. In this case, adhesive peaks were always observed, suggesting a mechanical origin of the measured pull-off forces. The other type of force curves shows no adhesive peaks and exhibits juxtaposing of approaching and retraction curves, reflecting elastic deformations.

Understanding and Controlling Living/Inorganic Interfaces to Enable Reconfigurable Switchable Materials

DTIC Science & Technology

2018-03-01

of environmental conditions and surface treatment on binding affinity. 15. SUBJECT TERMS bacterial adhesion, genetically engineered proteins for...mannose binding both experimentally and in molecular dynamics simulation ............................................................ 6 Fig. 3 COMSOL...Research Laboratory (ARL) strengths (e.g., molecular biology/synthetic biology, biomolecular recognition, materials characterization and polymer science

Bacterial adhesion to surfaces and microbial safety of fresh produce

USDA-ARS?s Scientific Manuscript database

Consumption of fresh produce is a central component of a healthy diet. However, contamination of fresh and fresh-cut fruits and vegetables such as leafy greens, tomatoes, cantaloupes is a source of ongoing concern for consumers. Growers, packers, processors and retailers work to control the incidenc...

Applications of bacterial cellulose and its composites in biomedicine.

PubMed

Rajwade, J M; Paknikar, K M; Kumbhar, J V

2015-03-01

Bacterial cellulose produced by few but specific microbial genera is an extremely pure natural exopolysaccharide. Besides providing adhesive properties and a competitive advantage to the cellulose over-producer, bacterial cellulose confers UV protection, ensures maintenance of an aerobic environment, retains moisture, protects against heavy metal stress, etc. This unique nanostructured matrix is being widely explored for various medical and nonmedical applications. It can be produced in various shapes and forms because of which it finds varied uses in biomedicine. The attributes of bacterial cellulose such as biocompatibility, haemocompatibility, mechanical strength, microporosity and biodegradability with its unique surface chemistry make it ideally suited for a plethora of biomedical applications. This review highlights these qualities of bacterial cellulose in detail with emphasis on reports that prove its utility in biomedicine. It also gives an in-depth account of various biomedical applications ranging from implants and scaffolds for tissue engineering, carriers for drug delivery, wound-dressing materials, etc. that are reported until date. Besides, perspectives on limitations of commercialisation of bacterial cellulose have been presented. This review is also an update on the variety of low-cost substrates used for production of bacterial cellulose and its nonmedical applications and includes patents and commercial products based on bacterial cellulose.

Hemocyte–hemocyte adhesion and nodulation reactions of the greater wax moth, Galleria mellonella are influenced by cholera toxin and its B-subunit

PubMed Central

Lapointe, Jason F.; Dunphy, Gary B.; Mandato, Craig A.

2012-01-01

Nodulation, the lepidopteran insect immune response to large numbers of microbes in the blood (hemolymph) consists of the coordination of the blood cell (hemocyte) types the granular cells and plasmatocytes in terms of granular cell–bacteria adhesion and hemocyte–hemocyte adhesion (microaggregation). Hemocyte–microbe adhesion is influenced by the secondary messenger, cAMP, and cAMP-dependent protein kinase A. In the present study, cholera toxin, an AB5 protein known to indirectly stimulate adenylate cyclase, is used to examine the hemocyte responses to glass, bacteria and hemocyte–hemocyte microaggregates. In vitro, this toxin induces a bimodal hemocyte adhesion response that varies with the holotoxin concentration in terms of the individual and aggregated hemocyte adhesion responses: the lower CTX concentration (1.2 nM) increases microaggregate adhesion and decreases individual hemocyte binding to glass, as does higher concentrations (6–120 nM), however microaggregates induced by lower concentrations do not adhere to glass. Cholera toxin-induced microaggregation is inhibited by RGDS, suggestive of integrin involvement. In vivo, cholera toxin (1.2–120 nM) injected into larvae induces also a bimodal hemocytic response: low levels (1.2–6 nM) cause reduced hemocyte adhesion, while high levels (12–120 nM) increase hemocyte release or mobilization of adhesive hemocyte counts in the hemolymph. Increasing levels of cholera toxin concomitantly injected with the non-pathogenic bacterium, Bacillus subtilis produces a bimodal pattern in bacterial removal from the hemolymph which correlates with nodule frequency in larvae injected with cholera toxin only. The effects of higher concentrations of cholera toxin in vitro (6–120 nM) and in vivo (12–120 nM) are mediated by the B-subunit, whereas the isolated A-subunit has no effect on hemocyte activity. Cholera toxin and its individual subunits did not detectably alter levels of intracellular cAMP in the hemocytes, suggesting a cAMP-independent mechanism stimulating the nodulation response. PMID:24371567

Influence of epoxy, polytetrafluoroethylene (PTFE) and rhodium surface coatings on surface roughness, nano-mechanical properties and biofilm adhesion of nickel titanium (Ni-Ti) archwires

NASA Astrophysics Data System (ADS)

Asiry, Moshabab A.; AlShahrani, Ibrahim; Almoammar, Salem; Durgesh, Bangalore H.; Kheraif, Abdulaziz A. Al; Hashem, Mohamed I.

2018-02-01

Aim. To investigate the effect of epoxy, polytetrafluoroethylene (PTFE) and rhodium surface coatings on surface roughness, nano-mechanical properties and biofilm adhesion of nickel titanium (Ni-Ti) archwires Methods. Three different coated (Epoxy, polytetrafluoroethylene (PTFE) and rhodium) and one uncoated Ni-Ti archwires were evaluated in the present study. Surface roughness (Ra) was assessed using a non-contact surface profilometer. The mechanical properties (nano-hardness and elastic modulus) were measured using a nanoindenter. Bacterial adhesion assays were performed using Streptococcus mutans (MS) and streptococcus sobrinus (SS) in an in-vitro set up. The data obtained were analyzed using analyses of variance, Tukey’s post hoc test and Pearson’s correlation coefficient test. Result. The highest Ra values (1.29 ± 0.49) were obtained for epoxy coated wires and lowest Ra values (0.29 ± 0.16) were obtained for the uncoated wires. No significant differences in the Ra values were observed between the rhodium coated and uncoated archwires (P > 0.05). The highest nano-hardness (3.72 ± 0.24) and elastic modulus values (61.15 ± 2.59) were obtained for uncoated archwires and the lowest nano-hardness (0.18 ± 0.10) and elastic modulus values (4.84 ± 0.65) were observed for epoxy coated archwires. No significant differences in nano-hardness and elastic modulus values were observed between the coated archwires (P > 0.05). The adhesion of Streptococcus mutans (MS) to the wires was significantly greater than that of streptococcus sobrinus (SS). The epoxy coated wires demonstrated an increased adhesion of MS and SS and the uncoated wires demonstrated decreased biofilm adhesion. The Spearman correlation test showed that MS and SS adhesion was positively correlated with the surface roughness of the wires. Conclusion. The different surface coatings significantly influence the roughness, nano-mechanical properties and biofilm adhesion parameters of the archwires. The evaluated parameters were most influenced by epoxy coating followed by PTFE and rhodium coating. A positive correlation was detected between surface roughness and biofilm adhesion.

Sealing effect of a polysaccharide nanosheet for murine cecal puncture.

PubMed

Fujie, Toshinori; Kinoshita, Manabu; Shono, Satoshi; Saito, Akihiro; Okamura, Yosuke; Saitoh, Daizoh; Takeoka, Shinji

2010-07-01

Recent developments in nanobiotechnology have led us to develop a method of producing a free-standing polymer nanosheet composed of polysaccharides (ie, polysaccharide nanosheet) with a thickness of tens of nanometers. Owing to its enormous aspect ratio, the polysaccharide nanosheet is semi-absorbent and has a physical adhesive strength 7.5-fold greater than that of conventional films of >1 microm thickness. Herein, we have investigated the therapeutic sealing effect of this polysaccharide nanosheet on murine cecal puncture as a wound dressing material. Murine cecum was punctured and then overlapped with the polysaccharide nanosheet. Thereafter, we evaluated its sealing effect on bacterial peritonitis as well as the protection offered by the polysaccharide nanosheet against bacterial permeability using an in vitro transmembrane assay. The 39-nm-thick polysaccharide nanosheet overlapped tightly the perforated cecum. No adhering agents were required because of the ability of the polysaccharide nanosheet to adhere to the tissue surface by physical adsorption (eg, van der Waals interaction). Sealing the perforated cecum with the polysaccharide nanosheet increased survival rate without postoperative adhesion by comparison with untreated mice (90 vs 30%; P < .01). These data were supported by the improvement in peritonitis related to bacterial counts, white blood cell counts, and the serum tumor necrosis factor level. Moreover, using an in vitro transmembrane assay, we showed that the polysaccharide nanosheet inhibited effectively bacterial penetration. We have demonstrated the potential clinical benefits of the nanosheet-type biomaterial that can be used for repairing a cecal colotomy without chemical bonding agents. Copyright 2010 Mosby, Inc. All rights reserved.

Phosphorylcholine impairs susceptibility to biofilm formation of hydrogel contact lenses.

PubMed

Selan, Laura; Palma, Stefano; Scoarughi, Gian Luca; Papa, Rosanna; Veeh, Richard; Di Clemente, Daniele; Artini, Marco

2009-01-01

To compare silicone-hydrogel, poly(2-hydroxyethyl methacrylate) (pHEMA), and phosphorylcholine-coated (PC-C) contact lenses in terms of their susceptibility to biofilm formation by Staphylococcus epidermidis and Pseudomonas aeruginosa. Laboratory investigation. Biofilm formation on colonized test lenses was evaluated with confocal microscopy and in vitro antibiotic susceptibility assays. The results of the latter assays were compared with those performed on planktonic cultures of the same organism. For both microorganisms, sessile colonies on silicone-hydrogel and pHEMA lenses displayed lower antibiotic susceptibility than their planktonic counterparts. In contrast, the susceptibility of cultures growing on PC-C lenses was comparable with that for planktonic cultures. In particular, minimum inhibitory concentration for Tazocin (piperacillin plus tazobactam; Wyeth Pharmaceuticals, Aprilia, Italy; S. epidermidis) and gentamicin (P. aeruginosa) was identical, either in the presence of PC-C support or in planktonic cultures (Tazocin,

Biofilm and Planktonic Bacterial and Fungal Communities Transforming High-Molecular-Weight Polycyclic Aromatic Hydrocarbons

PubMed Central

Folwell, Benjamin D.

2016-01-01

High-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs) are natural components of fossil fuels that are carcinogenic and persistent in the environment, particularly in oil sands process-affected water (OSPW). Their hydrophobicity and tendency to adsorb to organic matter result in low bioavailability and high recalcitrance to degradation. Despite the importance of microbes for environmental remediation, little is known about those involved in HMW-PAH transformations. Here, we investigated the transformation of HMW-PAHs using samples of OSPW and compared the bacterial and fungal community compositions attached to hydrophobic filters and in suspension. It was anticipated that the hydrophobic filters with sorbed HMW-PAHs would select for microbes that specialize in adhesion. Over 33 days, more pyrene was removed (75% ± 11.7%) than the five-ring PAHs benzo[a]pyrene (44% ± 13.6%) and benzo[b]fluoranthene (41% ± 12.6%). For both bacteria and fungi, the addition of PAHs led to a shift in community composition, but thereafter the major factor determining the fungal community composition was whether it was in the planktonic phase or attached to filters. In contrast, the major determinant of the bacterial community composition was the nature of the PAH serving as the carbon source. The main bacteria enriched by HMW-PAHs were Pseudomonas, Bacillus, and Microbacterium species. This report demonstrates that OSPW harbors microbial communities with the capacity to transform HMW-PAHs. Furthermore, the provision of suitable surfaces that encourage PAH sorption and microbial adhesion select for different fungal and bacterial species with the potential for HMW-PAH degradation. PMID:26850299

Molecular mechanisms involved in vascular interactions of the Lyme disease pathogen in a living host.

PubMed

Norman, M Ursula; Moriarty, Tara J; Dresser, Ashley R; Millen, Brandie; Kubes, Paul; Chaconas, George

2008-10-03

Hematogenous dissemination is important for infection by many bacterial pathogens, but is poorly understood because of the inability to directly observe this process in living hosts at the single cell level. All disseminating pathogens must tether to the host endothelium despite significant shear forces caused by blood flow. However, the molecules that mediate tethering interactions have not been identified for any bacterial pathogen except E. coli, which tethers to host cells via a specialized pillus structure that is not found in many pathogens. Furthermore, the mechanisms underlying tethering have never been examined in living hosts. We recently engineered a fluorescent strain of Borrelia burgdorferi, the Lyme disease pathogen, and visualized its dissemination from the microvasculature of living mice using intravital microscopy. We found that dissemination was a multistage process that included tethering, dragging, stationary adhesion and extravasation. In the study described here, we used quantitative real-time intravital microscopy to investigate the mechanistic features of the vascular interaction stage of B. burgdorferi dissemination. We found that tethering and dragging interactions were mechanistically distinct from stationary adhesion, and constituted the rate-limiting initiation step of microvascular interactions. Surprisingly, initiation was mediated by host Fn and GAGs, and the Fn- and GAG-interacting B. burgdorferi protein BBK32. Initiation was also strongly inhibited by the low molecular weight clinical heparin dalteparin. These findings indicate that the initiation of spirochete microvascular interactions is dependent on host ligands known to interact in vitro with numerous other bacterial pathogens. This conclusion raises the intriguing possibility that fibronectin and GAG interactions might be a general feature of hematogenous dissemination by other pathogens.

Attachment of Salmonella serovars and Listeria monocytogenes to stainless steel and plastic conveyor belts.

PubMed

Veluz, G A; Pitchiah, S; Alvarado, C Z

2012-08-01

In poultry industry, cross-contamination due to processing equipment and contact surfaces is very common. This study examined the extent of bacterial attachment to 6 different types and design of conveyor belts: stainless steel-single loop, stainless steel-balance weave, polyurethane with mono-polyester fabric, acetal, polypropylene mesh top, and polypropylene. Clean conveyor belts were immersed separately in either a cocktail of Salmonella serovars (Salmonella Typhimurium and Salmonella Enteritidis) or Listeria monocytogenes strains (Scott A, Brie 1, ATCC 6744) for 1 h at room temperature. Soiled conveyor chips were dipped in poultry rinses contaminated with Salmonella or Listeria cocktail and incubated at 10°C for 48 h. The polyurethane with mono-polyester fabric conveyor belt and chip exhibited a higher (P<0.05) mean number of attached Salmonella serovars (clean: 1.6 to 3.6 cfu/cm2; soiled: 0.8 to 2.4 cfu/cm2) and L. monocytogenes (clean: 4.0 to 4.3 cfu/cm2; soiled: 0.3 to 2.1 cfu/cm2) in both clean and soiled conditions. The stainless steel conveyor belt attached a lower (P<0.05) number of Salmonella serovars (clean: 0 to 2.6 cfu/cm2; soiled: 0.4 to 1.3 cfu/cm2) and L. monocytogenes (clean: 0.4 to 2.9 cfu/cm2; soiled: 0 to 0.7 cfu/cm2) than the polymeric materials, indicating weaker adhesion properties. Plastic conveyor belts exhibited stronger bacterial adhesion compared with stainless steel. The result suggests the importance of selecting the design and finishes of conveyor belt materials that are most resistant to bacterial attachment.

Applying thermosettable zwitterionic copolymers as general fouling-resistant and thermal-tolerant biomaterial interfaces.

PubMed

Chou, Ying-Nien; Chang, Yung; Wen, Ten-Chin

2015-05-20

We introduced a thermosettable zwitterionic copolymer to design a high temperature tolerance biomaterial as a general antifouling polymer interface. The original synthetic fouling-resistant copolymer, poly(vinylpyrrolidone)-co-poly(sulfobetaine methacrylate) (poly(VP-co-SBMA)), is both thermal-tolerant and fouling-resistant, and the antifouling stability of copolymer coated interfaces can be effectively controlled by regulating the VP/SBMA composition ratio. We studied poly(VP-co-SBMA) copolymer gels and networks with a focus on their general resistance to protein, cell, and bacterial bioadhesion, as influenced by the thermosetting process. Interestingly, we found that the shape of the poly(VP-co-SBMA) copolymer material can be set at a high annealing temperature of 200 °C while maintaining good antifouling properties. However, while the zwitterionic PSBMA polymer gels were bioinert as expected, control of the fouling resistance of the PSBMA polymer networks was lost in the high temperature annealing process. A poly(VP-co-SBMA) copolymer network composed of PSBMA segments at 32 mol % showed reduced fibrinogen adsorption, tissue cell adhesion, and bacterial attachment, but a relatively higher PSBMA content of 61 mol % was required to optimize resistance to platelet adhesion and erythrocyte attachment to confer hemocompatibility to human blood. We suggest that poly(VP-co-SBMA) copolymers capable of retaining stable fouling resistance after high temperature shaping have a potential application as thermosettable materials in a bioinert interface for medical devices, such as the thermosettable coating on a stainless steel blood-compatible metal stent investigated in this study.

A three-phase in-vitro system for studying Pseudomonas aeruginosa adhesion and biofilm formation upon hydrogel contact lenses

PubMed Central

2010-01-01

Background Pseudomonas aeruginosa is commonly associated with contact lens (CL) -related eye infections, for which bacterial adhesion and biofilm formation upon hydrogel CLs is a specific risk factor. Whilst P. aeruginosa has been widely used as a model organism for initial biofilm formation on CLs, in-vitro models that closely reproduce in-vivo conditions have rarely been presented. Results In the current investigation, a novel in-vitro biofilm model for studying the adherence of P. aeruginosa to hydrogel CLs was established. Nutritional and interfacial conditions similar to those in the eye of a CL wearer were created through the involvement of a solid:liquid and a solid:air interface, shear forces and a complex artificial tear fluid. Bioburdens varied depending on the CL material and biofilm maturation occurred after 72 h incubation. Whilst a range of biofilm morphologies were visualised including dispersed and adherent bacterial cells, aggregates and colonies embedded in extracellular polymer substances (EPS), EPS fibres, mushroom-like formations, and crystalline structures, a compact and heterogeneous biofilm morphology predominated on all CL materials. Conclusions In order to better understand the process of biofilm formation on CLs and to test the efficacy of CL care solutions, representative in-vitro biofilm models are required. Here, we present a three-phase biofilm model that simulates the environment in the eye of a CL wearer and thus generates biofilms which resemble those commonly observed in-situ. PMID:21062489

Physical stress and bacterial colonization

PubMed Central

Otto, Michael

2014-01-01

Bacterial surface colonizers are subject to a variety of physical stresses. During the colonization of human epithelia such as on the skin or the intestinal mucosa, bacteria mainly have to withstand the mechanical stress of being removed by fluid flow, scraping, or epithelial turnover. To that end, they express a series of molecules to establish firm attachment to the epithelial surface, such as fibrillar protrusions (pili) and surface-anchored proteins that bind to human matrix proteins. In addition, some bacteria – in particular gut and urinary tract pathogens – use internalization by epithelial cells and other methods such as directed inhibition of epithelial turnover to ascertain continued association with the epithelial layer. Furthermore, many bacteria produce multi-layered agglomerations called biofilms with a sticky extracellular matrix, providing additional protection from removal. This review will give an overview over the mechanisms human bacterial colonizers have to withstand physical stresses with a focus on bacterial adhesion. PMID:25212723

Antibacterial and remineralizing orthodontic adhesive containing quaternary ammonium resin monomer and amorphous calcium phosphate nanoparticles.

PubMed

Liu, Yan; Zhang, Ling; Niu, Li-Na; Yu, Tao; Xu, Hockin H K; Weir, Michael D; Oates, Thomas W; Tay, Franklin R; Chen, Ji-Hua

2018-05-01

To evaluate the bonding performance, antibacterial activity, and remineralization effect on enamel of the orthodontic adhesive containing MAE-DB and NACP. Eighty non-carious human premolars were divided into 3 groups: Transbond XT (TB), PEHB + 5% MAE-DB (PD), and PEHB + 40% NACP + 5% MAE-DB (PND). Premolars were bonded with orthodontic brackets, the first subgroup (n = 10) and the second subgroup (n = 10) were subjected to shear bond strength testing after immersed in water for 1 day and in demineralization solution for 28 days respectively and then tested surface roughness, while the third subgroup (n = 6) was used for microhardness evaluation after aged in demineralization solution for 28 days. For each adhesive, fifty disk samples were prepared for antibacterial study. Specimens measuring 12 mm × 2 mm × 2 mm were fabricated for ion release test. Bond strengths were in the order TB = PND > PND = PD for "1-day in water", and in the order TB = PND > PD for "28-days in pH 4 solution". No significant difference in the ARI scores for the three adhesive. Numerous bacteria adhered to TB surface, while PD and PND had minimal bacterial growth and activity. PND showed high levels of Ca and P ions release and enamel hardness. The surface roughness of enamel in PND was much lower than TB and PD and showed no significant difference with the sound, control enamel. PND adhesive with 5% MAE-DB and 40% NACP exhibits antibacterial and remineralizing capabilities, and did not adversely affect bond strength compared to commercial adhesive. Novel adhesive containing quaternary ammonium monomer and nano-amorphous calcium phosphate represents a promising candidate in combating enamel white spot lesions and even dental caries. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ellipsometric Measurement of Bacterial Films at Metal-Electrolyte Interfaces

PubMed Central

Busalmen, J. P.; de Sánchez, S. R.; Schiffrin, D. J.

1998-01-01

Ellipsometric measurements were used to monitor the formation of a bacterial cell film on polarized metal surfaces (Al-brass and Ti). Under cathodic polarization bacterial attachment was measured from changes in the ellipsometric angles. These were fitted to an effective medium model for a nonabsorbing bacterial film with an effective refractive index (nf) of 1.38 and a thickness (df) of 160 ± 10 nm. From the optical measurements a surface coverage of 17% was estimated, in agreement with direct microscopic observations. The influence of bacteria on the formation of oxide films was monitored by ellipsometry following the film growth in situ. A strong inhibition of metal oxide film formation was observed, which was assigned to the decrease in oxygen concentration due to the presence of bacteria. It is shown that the irreversible adhesion of bacteria to the surface can be monitored ellipsometrically. Electrophoretic mobility is proposed as one of the factors determining bacterial attachment. The high sensitivity of ellipsometry and its usefulness for the determination of growth of interfacial bacterial films is demonstrated. PMID:9758786

Enhancing the antibacterial performance of orthopaedic implant materials by fibre laser surface engineering

NASA Astrophysics Data System (ADS)

Chan, Chi-Wai; Carson, Louise; Smith, Graham C.; Morelli, Alessio; Lee, Seunghwan

2017-05-01

Implant failure caused by bacterial infection is extremely difficult to treat and usually requires the removal of the infected components. Despite the severe consequence of bacterial infection, research into bacterial infection of orthopaedic implants is still at an early stage compared to the effort on enhancing osseointegration, wear and corrosion resistance of implant materials. In this study, the effects of laser surface treatment on enhancing the antibacterial properties of commercially pure (CP) Ti (Grade 2), Ti6Al4V (Grade 5) and CoCrMo alloy implant materials were studied and compared for the first time. Laser surface treatment was performed by a continuous wave (CW) fibre laser with a near-infrared wavelength of 1064 nm in a nitrogen-containing environment. Staphylococcus aureus, commonly implicated in infection associated with orthopaedic implants, was used to investigate the antibacterial properties of the laser-treated surfaces. The surface roughness and topography of the laser-treated materials were analysed by a 2D roughness testing and by AFM. The surface morphologies before and after 24 h of bacterial cell culture were captured by SEM, and bacterial viability was determined using live/dead staining. Surface chemistry was analysed by XPS and surface wettability was measured using the sessile drop method. The findings of this study indicated that the laser-treated CP Ti and Ti6Al4V surfaces exhibited a noticeable reduction in bacterial adhesion and possessed a bactericidal effect. Such properties were attributable to the combined effects of reduced hydrophobicity, thicker and stable oxide films and presence of laser-induced nano-features. No similar antibacterial effect was observed in the laser-treated CoCrMo.

Production and Characterization of TiO2 Nanofilms for Hemocompatible and Photocatalytic Applications

NASA Astrophysics Data System (ADS)

Schvezov, C. E.; Vera, M. L.; Schuster, J. M.; Rosenberger, M. R.

2017-10-01

Titanium dioxide (TiO2) coatings are currently produced for hemocompatible and photocatalytic applications by using two techniques: sol-gel and anodic oxidation. In this review, the research advances on TiO2 nanofilms produced with these techniques are presented, with a focus on different aspects such as process parameters, morphology, roughness, crystal structure, adhesion, wear and erosion resistance, corrosion resistance, hemocompatibility, toxicity, plaque and bacterial adhesion, and heterogeneous photocatalysis of immobilized porous material. This review was presented at the 3rd Pan American Materials Congress at the 2017 TMS Annual Meeting and Exhibition in San Diego, California, USA.

Polymerisation, antibacterial and bioactivity properties of experimental orthodontic adhesives containing triclosan-loaded halloysite nanotubes.

PubMed

Degrazia, Felipe Weidenbach; Genari, Bruna; Leitune, Vicente Castelo Branco; Arthur, Rodrigo Alex; Luxan, Santiago Arias; Samuel, Susana Maria Werner; Collares, Fabrício Mezzomo; Sauro, Salvatore

2018-02-01

To evaluate the immediate enamel bond strength, in situ degree of conversion and the polymerisation rate of three experimental orthodontic adhesives containing triclosan-loaded halloysite nanotubes. The antibacterial and bioactivity properties of such experimental materials were also assessed. Three experimental orthodontic adhesives were formulated by incorporating triclosan-loaded halloysite nanotubes (TCN-HNT) at different concentrations (5wt%, 10wt% and 20wt%) into a resin blend (Control). The maximum polymerisation rate of the tested adhesives was evaluated trough FTIR, while Raman was used to analyse the in situ degree of conversion (DC) at the bracket/enamel interface. The shear bond strength (SBS) of the enamel-bonded specimens was assessed at 24h. The antibacterial properties of the experimental materials against S. Mutans were evaluate up to 72h, while, their bioactivity was evaluated after 14days of artificial saliva (AS) storage through SEM-EDS and Raman spectromicroscopy. Incorporation of TCN-HNT increased the polymerisation properties without interfering with the immediate bonding properties of the experimental adhesives. All experimental adhesives containing TCN-HNT inhibited bacterial growth at 24h, and induced mineral deposition after 14days of AS storage. At 72h, only the experimental system containing 20% TCN-HNT maintained such a capability. Adhesives doped with TCN-HNT present improved polymerisation properties and suitable bonding performance. However, only the adhesives containing TCN-HNT >10% might promote long-term antibacterial activity and reliable mineral deposition. The use of adhesives containing triclosan-loaded halloysite represents a promising "smart" approach to bond orthodontic brackets and bands; these might prevent enamel demineralisation and induce enamel remineralisation during the treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reducing Staphylococcus aureus biofilm formation on stainless steel 316L using functionalized self-assembled monolayers

PubMed Central

Kruszewski, Kristen M; Nistico, Laura; Longwell, Mark J; Hynes, Matthew J; Maurer, Joshua A

2013-01-01

Stainless steel 316L (SS316L) is a common material used in orthopedic implants. Bacterial colonization of the surface and subsequent biofilm development can lead to refractory infection of the implant. Since the greatest risk of infection occurs perioperatively, strategies that reduce bacterial adhesion during this time are important. As a strategy to limit bacterial adhesion and biofilm formation on SS316L, self-assembled monolayers (SAMs) were used to modify the SS316L surface. SAMs with long alkyl chains terminated with hydrophobic (-CH3) or hydrophilic (oligoethylene glycol) tail groups were used to form coatings and in an orthogonal approach, SAMs were used to immobilize gentamicin or vancomycin on SS316L for the first time to form an “active” antimicrobial coating to inhibit early biofilm development. Modified SS316L surfaces were characterized using surface infrared spectroscopy, contact angles, MALDI-TOF mass spectrometry and atomic force microscopy. The ability of SAM-modified SS316L to retard biofilm development by Staphylococcus aureus was functionally tested using confocal scanning laser microscopy with COMSTAT image analysis, scanning electron microscopy and colony forming unit analysis. Neither hydrophobic nor hydrophilic SAMs reduced biofilm development. However, gentamicin-linked and vancomycin-linked SAMs significantly reduced S. aureus biofilm formation for up to 24 and 48 hours, respectively. PMID:23498233

In Vitro Assessment of Early Bacterial Activity on Micro/Nanostructured Ti6Al4V Surfaces.

PubMed

Valdez-Salas, Benjamin; Beltrán-Partida, Ernesto; Castillo-Uribe, Sandra; Curiel-Álvarez, Mario; Zlatev, Roumen; Stoytcheva, Margarita; Montero-Alpírez, Gisela; Vargas-Osuna, Lidia

2017-05-18

It is imperative to understand and systematically compare the initial interactions between bacteria genre and surface properties. Thus, we fabricated a flat, anodized with 80 nm TiO₂ nanotubes (NTs), and a rough Ti6Al4V surface. The materials were characterized using field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). We cultured in vitro Staphylococcus epidermidis ( S. epidermidis ) and Pseudomonas aeruginosa ( P. aeruginosa ) to evaluate the bacterial-surface behavior by FE-SEM and viability calculation. In addition, the initial effects of human osteoblasts were tested on the materials. Gram-negative bacteria showed promoted adherence and viability over the flat and rough surface, while NTs displayed opposite activity with altered morphology. Gram-positive bacteria illustrated similar cellular architecture over the surfaces but with promoted surface adhesion bonds on the flat alloy. Rough surfaces supported S. epidermidis viability, whilst NTs exhibited lower vitality. NTs advocated promoted better osteoblast organization with enhanced vitality. Gram-positive bacteria suggested preferred adhesion capability over flat and carbon-rich surfaces. Gram-negative bacteria were strongly disturbed by NTs but largely stimulated by flat and rough materials. Our work proposed that the chemical profile of the material surface and the bacterial cell wall characteristics might play an important role in the bacteria-surface interactions.

Reducing Staphylococcus aureus biofilm formation on stainless steel 316L using functionalized self-assembled monolayers.

PubMed

Kruszewski, Kristen M; Nistico, Laura; Longwell, Mark J; Hynes, Matthew J; Maurer, Joshua A; Hall-Stoodley, Luanne; Gawalt, Ellen S

2013-05-01

Stainless steel 316L (SS316L) is a common material used in orthopedic implants. Bacterial colonization of the surface and subsequent biofilm development can lead to refractory infection of the implant. Since the greatest risk of infection occurs perioperatively, strategies that reduce bacterial adhesion during this time are important. As a strategy to limit bacterial adhesion and biofilm formation on SS316L, self-assembled monolayers (SAMs) were used to modify the SS316L surface. SAMs with long alkyl chains terminated with hydrophobic (-CH3) or hydrophilic (oligoethylene glycol) tail groups were used to form coatings and in an orthogonal approach, SAMs were used to immobilize gentamicin or vancomycin on SS316L for the first time to form an "active" antimicrobial coating to inhibit early biofilm development. Modified SS316L surfaces were characterized using surface infrared spectroscopy, contact angles, MALDI-TOF mass spectrometry and atomic force microscopy. The ability of SAM-modified SS316L to retard biofilm development by Staphylococcus aureus was functionally tested using confocal scanning laser microscopy with COMSTAT image analysis, scanning electron microscopy and colony forming unit analysis. Neither hydrophobic nor hydrophilic SAMs reduced biofilm development. However, gentamicin-linked and vancomycin-linked SAMs significantly reduced S. aureus biofilm formation for up to 24 and 48 h, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

Staphylococcus aureus Extracellular Adherence Protein Triggers TNFα Release, Promoting Attachment to Endothelial Cells via Protein A

PubMed Central

Edwards, Andrew M.; Bowden, Maria Gabriela; Brown, Eric L.; Laabei, Maisem; Massey, Ruth C.

2012-01-01

Staphylococcus aureus is a leading cause of bacteraemia, which frequently results in complications such as infective endocarditis, osteomyelitis and exit from the bloodstream to cause metastatic abscesses. Interaction with endothelial cells is critical to these complications and several bacterial proteins have been shown to be involved. The S. aureus extracellular adhesion protein (Eap) has many functions, it binds several host glyco-proteins and has both pro- and anti-inflammatory activity. Unfortunately its role in vivo has not been robustly tested to date, due to difficulties in complementing its activity in mutant strains. We previously found Eap to have pro-inflammatory activity, and here show that purified native Eap triggered TNFα release in whole human blood in a dose-dependent manner. This level of TNFα increased adhesion of S. aureus to endothelial cells 4-fold via a mechanism involving protein A on the bacterial surface and gC1qR/p33 on the endothelial cell surface. The contribution this and other Eap activities play in disease severity during bacteraemia was tested by constructing an isogenic set of strains in which the eap gene was inactivated and complemented by inserting an intact copy elsewhere on the bacterial chromosome. Using a murine bacteraemia model we found that Eap expressing strains cause a more severe infection, demonstrating its role in invasive disease. PMID:22905199

S-layer proteins from Lactobacillus sp. inhibit bacterial infection by blockage of DC-SIGN cell receptor.

PubMed

Prado Acosta, Mariano; Ruzal, Sandra M; Cordo, Sandra M

2016-11-01

Many species of Lactobacillus sp. possess Surface(s) layer proteins in their envelope. Among other important characteristics S-layer from Lactobacillus acidophilus binds to the cellular receptor DC-SIGN (Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin; CD209), which is involved in adhesion and infection of several families of bacteria. In this report we investigate the activity of new S-layer proteins from the Lactobacillus family (Lactobacillus acidophilus, Lactobacillus brevis, Lactobacillus helveticus and Lactobacillus kefiri) over the infection of representative microorganisms important to human health. After the treatment of DC-SIGN expressing cells with these proteins, we were able to diminish bacterial infection by up to 79% in both gram negative and mycobacterial models. We discovered that pre-treatment of the bacteria with S-layers from Lactobacillus acidophilus and Lactobacillus brevis reduced bacteria viability but also prevent infection by the pathogenic bacteria. We also proved the importance of the glycosylation of the S-layer from Lactobacillus kefiri in the binding to the receptor and thus inhibition of infection. This novel characteristic of the S-layers proteins may contribute to the already reported pathogen exclusion activity for these Lactobacillus probiotic strains; and might be also considered as a novel enzymatic antimicrobial agents to inhibit bacterial infection and entry to host cells. Copyright © 2016 Elsevier B.V. All rights reserved.

Trehalose does not affect the functions of human neutrophils in vitro.

PubMed

Tanaka, Koji; Kawamura, Mikio; Otake, Kohei; Toiyama, Yuji; Okugawa, Yoshinaga; Inoue, Yasuhiro; Uchida, Keiichi; Araki, Toshimitsu; Mohri, Yasuhiko; Kusunoki, Masato

2014-02-01

Trehalose, naturally occurring disaccharide, has been reported to prevent postoperative abdominal adhesions in animal models. We investigated whether trehalose affects the function of human polymorphonuclear neutrophils (PMNs) in vitro to assess the feasibility of its clinical application as an anti-adhesive barrier. Human PMNs were obtained from 17 healthy volunteers. Escherichia coli and Staphylococcus aureus were used for the bacterial infection model, whereas lipopolysaccharide (LPS) and interleukin (IL)-1β were used for inflammation induction model. The PMN phagocytosis rates of bacteria and apoptosis/necrosis were assessed on trehalose, maltose, and control media. Cytokines; namely, tumor necrosis factor-α, IL-1α, IL-1Ra, IL-6, and IL-8; and PMN-elastase were measured on each medium in both models. There were no significant differences in the phagocytosis rates, apoptosis/necrosis rates, or levels of all cytokines or PMN-elastase among the three media in the bacterial infection model. There were also no significant differences in the levels of all cytokines and PMN-elastase among the three media in the IL-1β inflammation induction model. PMN-elastase was lower in trehalose and maltose medium after LPS stimulation, at 3 and 24 h. Our results suggest that trehalose does not affect the cellular function, cytokine production, or release of PMN-elastase of human PMNs in an in vitro bacterial infection model.

PHACOS, a functionalized bacterial polyester with bactericidal activity against methicillin-resistant Staphylococcus aureus

PubMed Central

Dinjaski, Nina; Fernández-Gutiérrez, Mar; Selvam, Shivaram; Parra-Ruiz, Francisco J.; Lehman, Susan M.; Román, Julio San; García, Ernesto; García, José L.; García, Andrés J.; Prieto, María Auxiliadora

2013-01-01

Biomaterial-associated infections represent a significant clinical problem, and treatment of these microbial infections is becoming troublesome due to the increasing number of antibiotic-resistant strains. Here, we report a naturally functionalized bacterial polyhydroxyalkanoate (PHACOS) with antibacterial properties. We demonstrate that PHACOS selectively and efficiently inhibits the growth of methicillin-resistant Staphylococcus aureus (MRSA) both in vitro and in vivo. This ability has been ascribed to the functionalized side chains containing thioester groups. Significantly less (3.2-fold) biofilm formation of S. aureus was detected on PHACOS compared to biofilms formed on control poly(3-hydroxyoctanoate-co-hydroxyhexanoate) and poly(ethylene terephthalate), but no differences were observed in bacterial adhesion among these polymers. PHACOS elicited minimal cytotoxic and inflammatory effects on murine macrophages and supported normal fibroblast adhesion. In vivo fluorescence imaging demonstrated minimal inflammation and excellent antibacterial activity for PHACOS compared to controls in an in vivo model of implant-associated infection. Additionally, reductions in neutrophils and macrophages in the vicinity of sterile PHACOS compared to sterile PHO implant were observed by immunohistochemistry. Moreover, a similar percentage of inflammatory cells was found in the tissue surrounding sterile PHACOS and S. aureus pre-colonized PHACOS implants, and these levels were significantly lower than S. aureus pre-colonized control polymers. These findings support a contact active surface mode of antibacterial action for PHACOS and establish this functionalized polyhydroxyalkanoate as an infection-resistant biomaterial. PMID:24094939

Surface glycosaminoglycans mediate adherence between HeLa cells and Lactobacillus salivarius Lv72.

PubMed

Martín, Rebeca; Martín, Carla; Escobedo, Susana; Suárez, Juan E; Quirós, Luis M

2013-09-17

The adhesion of lactobacilli to the vaginal surface is of paramount importance to develop their probiotic functions. For this reason, the role of HeLa cell surface proteoglycans in the attachment of Lactobacillus salivarius Lv72, a mutualistic strain of vaginal origin, was investigated. Incubation of cultures with a variety of glycosaminoglycans (chondroitin sulfate A and C, heparin and heparan sulfate) resulted in marked binding interference. However, no single glycosaminoglycan was able to completely abolish cell binding, the sum of all having an additive effect that suggests cooperation between them and recognition of specific adhesins on the bacterial surface. In contrast, chondroitin sulfate B enhanced cell to cell attachment, showing the relevance of the stereochemistry of the uronic acid and the sulfation pattern on binding. Elimination of the HeLa surface glycosaminoglycans with lyases also resulted in severe adherence impairment. Advantage was taken of the Lactobacillus-glycosaminoglycans interaction to identify an adhesin from the bacterial surface. This protein, identify as a soluble binding protein of an ABC transporter system (OppA) by MALDI-TOF/(MS), was overproduced in Escherichia coli, purified and shown to interfere with L. salivarius Lv72 adhesion to HeLa cells. These data suggest that glycosaminoglycans play a fundamental role in attachment of mutualistic bacteria to the epithelium that lines the cavities where the normal microbiota thrives, OppA being a bacterial adhesin involved in the process.

Bacterial adhesion on commercially pure titanium and anatase-coated titanium healing screws: an in vivo human study.

PubMed

Scarano, Antonio; Piattelli, Adriano; Polimeni, Antonella; Di Iorio, Donato; Carinci, Francesco

2010-10-01

Little is known about the mechanisms of bacterial interaction with implant materials in the oral cavity. Other surface characteristics, in addition to surface roughness, seem to be extremely important in relation to plaque formation. Different adhesion affinities of bacteria were reported for different materials. Anatase is a nanoparticle that can be applied to titanium surfaces as a coating. The anatase coating gives special characteristics to the implant surface, including some genetic effects on osteoblasts. In this study, the antibacterial effect of anatase is investigated. The aim of this study is to characterize the percentages of surfaces covered by bacteria on commercially pure (cp) titanium and anatase-coated healing screws. Ten patients participated in this study. The protocol of the study was approved by the ethics committee of the University of Chieti-Pescara. A total of 20 healing screws (10 test and 10 control screws) were used in the study. The control screws were made of cp titanium, whereas the test screws were coated with anatase. Cleaning procedures and agents for chemical plaque control were not applied to the healing screws for the complete duration of the test period. After 7 days, all healing screws were removed, substituted, and processed under scanning electron microscopy for evaluation of the portions of the surfaces covered by bacteria. The supracrestal screw surfaces covered by bacteria on test specimens were not significantly lower than those of control screws (P = 0.174). The subcrestal screw surfaces and threads covered by bacteria on test specimens were significantly lower than those of control screws, and P values were 0.001 and 0.000, respectively. Results show that anatase could be a suitable material for coating implant abutments, with a low colonization potential.

Antibacterial and remineralization effects of orthodontic bonding agents containing bioactive glass

PubMed Central

Kim, Dong-Hyun; Song, Chang Weon; Yoon, Seog-Young; Kim, Se-Yeon; Na, Hee Sam; Chung, Jin

2018-01-01

Objective The aim of this study was to evaluate the mechanical and biological properties of orthodontic bonding agents containing silver- or zinc-doped bioactive glass (BAG) and determine the antibacterial and remineralization effects of these agents. Methods BAG was synthesized using the alkali-mediated solgel method. Orthodontic bonding agents containing BAG were prepared by mixing BAG with flowable resin. Transbond™ XT (TXT) and Charmfil™ Flow (CF) were used as controls. Ion release, cytotoxicity, antibacterial properties, the shear bond strength, and the adhesive remnant index were evaluated. To assess the remineralization properties of BAG, micro-computed tomography was performed after pH cycling. Results The BAG-containing bonding agents showed no noticeable cytotoxicity and suppressed bacterial growth. When these bonding agents were used, demineralization after pH cycling began approximately 200 to 300 µm away from the bracket. On the other hand, when CF and TXT were used, all surfaces that were not covered by the adhesive were demineralized after pH cycling. Conclusions Our findings suggest that orthodontic bonding agents containing silver- or zinc-doped BAG have stronger antibacterial and remineralization effects compared with conventional orthodontic adhesives; thus, they are suitable for use in orthodontic practice. PMID:29732302

On the role of extracellular polymeric substances during early stages of Xylella fastidiosa biofilm formation.

PubMed

Lorite, Gabriela S; de Souza, Alessandra A; Neubauer, Daniel; Mizaikoff, Boris; Kranz, Christine; Cotta, Mônica A

2013-02-01

The structural integrity and protection of bacterial biofilms are intrinsically associated with a matrix of extracellular polymeric substances (EPS) produced by the bacteria cells. However, the role of these substances during biofilm adhesion to a surface remains largely unclear. In this study, the influence of EPS on Xylella fastidiosa biofilm formation was investigated. This bacterium is associated with economically important plant diseases; it presents a slow growth rate and thus allows us to pinpoint more precisely the early stages of cell-surface adhesion. Scanning electron microscopy and atomic force microscopy show evidence of EPS production in such early stages and around individual bacteria cells attached to the substrate surface even a few hours after inoculation. In addition, EPS formation was investigated via attenuated total reflectance (ATR) Fourier transform infrared spectroscopy (FTIR). To this end, X. fastidiosa cells were inoculated within an ATR liquid cell assembly. IR-ATR spectra clearly reveal EPS formation already during the early stages of X. fastidiosa biofilm formation, thereby providing supporting evidence for the hypothesis of the relevance of the EPS contribution to the adhesion process. Copyright © 2012 Elsevier B.V. All rights reserved.

Antimicrobial design of titanium surface that kill sessile bacteria but support stem cells adhesion

NASA Astrophysics Data System (ADS)

Zhu, Chen; Bao, Ni-Rong; Chen, Shuo; Zhao, Jian-Ning

2016-12-01

Implant-related bacterial infection is one of the most severe postoperative complications in orthopedic or dental surgery. In this context, from the perspective of surface modification, increasing efforts have been made to enhance the antibacterial capability of titanium surface. In this work, a hierarchical hybrid surface architecture was firstly constructed on titanium surface by two-step strategy of acid etching and H2O2 aging. Then silver nanoparticles were firmly immobilized on the hierarchical surface by ion implantation, showing no detectable release of silver ions from surface. The designed titanium surface showed good bioactivity. More importantly, this elaborately designed titanium surface can effectively inactivate the adherent S. aureus on surface by virtue of a contact-killing mode. Meanwhile, the designed titanium surface can significantly facilitate the initial adhesion and spreading behaviors of bone marrow mesenchymal stem cells (MSCs) on titanium. The results suggested that, the elaborately designed titanium surface might own a cell-favoring ability that can help mammalian cells win the initial adhesion race against bacteria. We hope the present study can provide a new insight for the better understanding and designing of antimicrobial titanium surface, and pave the way to satisfying clinical requirements.

Organization and PprB-dependent control of the Pseudomonas aeruginosa tad Locus, involved in Flp pilus biology.

PubMed

Bernard, Christophe S; Bordi, Christophe; Termine, Elise; Filloux, Alain; de Bentzmann, Sophie

2009-03-01

Bacterial attachment to the substratum involves several cell surface organelles, including various types of pili. The Pseudomonas aeruginosa Tad machine assembles type IVb pili, which are required for adhesion to abiotic surfaces and to eukaryotic cells. Type IVb pili consist of a major subunit, the Flp pilin, processed by the FppA prepilin peptidase. In this study, we investigated the regulatory mechanism of the tad locus. We showed that the flp gene is expressed late in the stationary growth phase in aerobic conditions. We also showed that the tad locus was composed of five independent transcriptional units. We used transcriptional fusions to show that tad gene expression was positively controlled by the PprB response regulator. We subsequently showed that PprB bound to the promoter regions, directly controlling the expression of these genes. We then evaluated the contribution of two genes, tadF and rcpC, to type IVb pilus assembly. The deletion of these two genes had no effect on Flp production, pilus assembly, or Flp-mediated adhesion to abiotic surfaces in our conditions. However, our results suggest that the putative RcpC protein modifies the Flp pilin, thereby promoting Flp-dependent adhesion to eukaryotic cells.

Increased osteoblast and decreased Staphylococcus epidermidis functions on nanophase ZnO and TiO2.

PubMed

Colon, Gabriel; Ward, Brian C; Webster, Thomas J

2006-09-01

Many engineers and surgeons trace implant failure to poor osseointegration (or the bonding of an orthopedic implant to juxtaposed bone) and/or bacteria infection. By using novel nanotopographies, researchers have shown that nanostructured ceramics, carbon fibers, polymers, metals, and composites enhance osteoblast adhesion and calcium/phosphate mineral deposition. However, the function of bacteria on materials with nanostructured surfaces remains largely uninvestigated. This is despite the fact that during normal surgical insertion of an orthopedic implant, bacteria from the patient's own skin and/or mucosa enters the wound site. These bacteria (namely, Staphylococcus epidermidis) irreversibly adhere to an implant surface while various physiological stresses induce alterations in the bacterial growth rate leading to biofilm formation. Because of their integral role in determining the success of orthopedic implants, the objective of this in vitro study was to examine the functions of (i) S. epidermidis and (ii) osteoblasts (or bone-forming cells) on ZnO and titania (TiO(2)), which possess nanostructured compared to microstructured surface features. ZnO is a well-known antimicrobial agent and TiO(2) readily forms on titanium once implanted. Results of this study provided the first evidence of decreased S. epidermidis adhesion on ZnO and TiO(2) with nanostructured when compared with microstructured surface features. Moreover, compared with microphase formulations, results of this study showed increased osteoblast adhesion, alkaline phosphatase activity, and calcium mineral deposition on nanophase ZnO and TiO(2). In this manner, this study suggests that nanophase ZnO and TiO(2) may reduce S. epidermidis adhesion and increase osteoblast functions necessary to promote the efficacy of orthopedic implants.

NrdR Transcription Regulation: Global Proteome Analysis and Its Role in Escherichia coli Viability and Virulence

PubMed Central

Naveen, Vankadari; Hsiao, Chwan-Deng

2016-01-01

Bacterial ribonucleotide reductases (RNRs) play an important role in the synthesis of dNTPs and their expression is regulated by the transcription factors, NrdR and Fur. Recent transcriptomic studies using deletion mutants have indicated a role for NrdR in bacterial chemotaxis and in the maintenance of topoisomerase levels. However, NrdR deletion alone has no effect on bacterial growth or virulence in infected flies or in human blood cells. Furthermore, transcriptomic studies are limited to the deletion strain alone, and so are inadequate for drawing biological implications when the NrdR repressor is active or abundant. Therefore, further examination is warranted of changes in the cellular proteome in response to both NrdR overexpression, as well as deletion, to better understand its functional relevance as a bacterial transcription repressor. Here, we profile bacterial fate under conditions of overexpression and deletion of NrdR in E. coli. Biochemical assays show auxiliary zinc enhances the DNA binding activity of NrdR. We also demonstrate at the physiological level that increased nrdR expression causes a significant reduction in bacterial growth and fitness even at normal temperatures, and causes lethality at elevated temperatures. Corroborating these direct effects, global proteome analysis following NrdR overexpression showed a significant decrease in global protein expression. In parallel, studies on complementary expression of downregulated essential genes polA, eno and thiL showed partial rescue of the fitness defect caused by NrdR overexpression. Deletion of downregulated non-essential genes ygfK and trxA upon NrdR overexpression resulted in diminished bacterial growth and fitness suggesting an additional role for NrdR in regulating other genes. Moreover, in comparison with NrdR deletion, E. coli cells overexpressing NrdR showed significantly diminished adherence to human epithelial cells, reflecting decreased bacterial virulence. These results suggest that elevated expression of NrdR could be a suitable means to retard bacterial growth and virulence, as its elevated expression reduces bacterial fitness and impairs host cell adhesion. PMID:27275780

Adhesion activity of glyceraldehyde-3-phosphate dehydrogenase in a Chinese Streptococcus suis type 2 strain.

PubMed

Wang, Kaicheng; Lu, Chengping

2007-01-01

A total of 36 streptococcal strains, including seven S. equi ssp.zooepidemicus, two S. suis type 1 (SS1), 24 SS2, two SS9, and one SS7, were tested for glyceraldehyde-3-phosphate dehydrogenase gene (gapdh). Except from non-virulent SS2 strain T1 5, all strains harboured gapdh. The gapdh of Chinese Sichuan SS2 isolate ZY05719 and Jiangsu SS2 isolate HA9801 were sequenced and then compared with published sequences in the GenBank. The comparison revealed a 99.9 % and 99.8 % similarity of ZY05719 and HA9801, respectively, with the published sequence. Adherence assay data demonstrated a significant ((p<0.05)) reduction in adhesion of SS2 in HEp-2 cells pre-incubated with purified GAPDH compared to non pre-incubated controls, suggesting the GAPDH mediates SS2 bacterial adhesion to host cells.

The anti-adherence effect of Piper betle and Psidium guajava extracts on the adhesion of early settlers in dental plaque to saliva-coated glass surfaces.

PubMed

Razak, Fathilah Abdul; Rahim, Zubaidah Haji Abd

2003-12-01

The aqueous extracts of Piper betle and Psidium guajava were prepared and tested for their anti-adherence effect on the adhesion of early plaque settlers (Strep. mitis, Strep. sanguinis and Actinomyces sp.). The saliva-coated glass surfaces were used to simulate the pellicle-coated enamel surface in the oral cavity. Our results showed that the anti-adherence activities of Piper betle and Psidium guajava extracts towards the bacteria were different between the bacterial species. Psidium guajava was shown to have a slightly greater anti-adherence effect on Strep. sanguinis by 5.5% and Actinomyces sp. by 10% and a significantly higher effect on Strep. mitis (70%) compared to Piper betle. The three bacterial species are known to be highly hydrophobic, and that hydrophobic bonding seemed to be an important factor in their adherence activities. It is therefore suggested that the plant extracts, in expressing their anti-adherence activities, could have altered the hydrophobic nature of the bonding between the bacteria and the saliva-coated glass surfaces.

Structural basis of host recognition and biofilm formation by Salmonella Saf pili

PubMed Central

2017-01-01

Pili are critical in host recognition, colonization and biofilm formation during bacterial infection. Here, we report the crystal structures of SafD-dsc and SafD-SafA-SafA (SafDAA-dsc) in Saf pili. Cell adherence assays show that SafD and SafA are both required for host recognition, suggesting a poly-adhesive mechanism for Saf pili. Moreover, the SafDAA-dsc structure, as well as SAXS characterization, reveals an unexpected inter-molecular oligomerization, prompting the investigation of Saf-driven self-association in biofilm formation. The bead/cell aggregation and biofilm formation assays are used to demonstrate the novel function of Saf pili. Structure-based mutants targeting the inter-molecular hydrogen bonds and complementary architecture/surfaces in SafDAA-dsc dimers significantly impaired the Saf self-association activity and biofilm formation. In summary, our results identify two novel functions of Saf pili: the poly-adhesive and self-associating activities. More importantly, Saf-Saf structures and functional characterizations help to define a pili-mediated inter-cellular oligomerizaiton mechanism for bacterial aggregation, colonization and ultimate biofilm formation. PMID:29125121

Surface functionalization of copper via oxidative graft polymerization of 2,2'-bithiophene and immobilization of silver nanoparticles for combating biocorrosion.

PubMed

Wan, Dong; Yuan, Shaojun; Neoh, K G; Kang, E T

2010-06-01

An environmentally benign approach to surface modification was developed to impart copper surface with enhanced resistance to corrosion, bacterial adhesion and biocorrosion. Oxidative graft polymerization of 2,2'-bithiophene from the copper surface with self-assembled 2,2'-bithiophene monolayer, and subsequent reduction of silver ions to silver nanoparticles (Ag NPs) on the surface, give rise to a homogeneous bithiophene polymer (PBT) film with densely coupled Ag NPs on the copper surface (Cu-g-PBT-Ag NP surface). The immobilized Ag NPs were found to significantly inhibit bacterial adhesion and enhance the antibacterial properties of the PBT modified copper surface. The corrosion inhibition performance of the functionalized copper substrates was evaluated by Tafel polarization curves and electrochemical impedance spectroscopy. Arising from the chemical affinity of thiols for the noble and coinage metals, the copper surface functionalized with both PBT brushes and Ag NPs also exhibits long-term stability, and is thus potentially useful for combating the combined problems of corrosion and biocorrosion in harsh marine and aquatic environments.

Surface energy modification for biomedical material by corona streamer plasma processing to mitigate bacterial adhesion

NASA Astrophysics Data System (ADS)

Alhamarneh, Ibrahim; Pedrow, Patrick

2011-10-01

Bacterial adhesion initiates biofouling of biomedical material but the processes can be reduced by adjusting the material's surface energy. The surface of surgical-grade 316L stainless steel (316L SS) had its hydrophilic property enhanced by processing in a corona streamer plasma reactor using atmospheric pressure Ar mixed with O2. Reactor excitation was 60 Hz ac high-voltage (<= 10 kV RMS) applied to a multi-needle-to-grounded-torus electrode configuration. Applied voltage and streamer current pulses were monitored with a broadband sensor system. When Ar/O2 plasma was used, the surface energy was enhanced more than with Ar plasma alone. Composition of the surface before and after plasma treatment was characterized by XPS. As the hydrophilicity of the treated surface increased so did percent of oxygen on the surface thus we concluded that reduction in contact angle was mainly due to new oxygen-containing functionalities. FTIR was used to identify oxygen containing groups on the surface. The aging effect that accompanies surface free energy adjustments was also observed.

Antimicrobial and Osseointegration Properties of Nanostructured Titanium Orthopaedic Implants.

PubMed

Jäger, Marcus; Jennissen, Herbert P; Dittrich, Florian; Fischer, Alfons; Köhling, Hedda Luise

2017-11-13

The surface design of titanium implants influences not only the local biological reactions but also affects at least the clinical result in orthopaedic application. During the last decades, strong efforts have been made to improve osteointegration and prevent bacterial adhesion to these surfaces. Following the rule of "smaller, faster, cheaper", nanotechnology has encountered clinical application. It is evident that the hierarchical implant surface micro- and nanotopography orchestrate the biological cascades of early peri-implant endosseous healing or implant loosening. This review of the literature gives a brief overview of nanostructured titanium-base biomaterials designed to improve osteointegration and prevent from bacterial infection.

Vibrational spectroscopy in the ophthalmological field

NASA Astrophysics Data System (ADS)

Bertoluzza, Alessandro; Monti, P.; Simoni, R.

1991-05-01

Some applications of vibrational (Raman and FT/IR) spectroscopy to the study of biocompatibility in the ophthalmological field are described. The structure arid elastic properties of a new hydrophobic fluorocarbon copolymer (FCC) are presented. Bacterial adhesion on its surface is also considered. The structure arid properties of soft contact lenses based on poly2--hydroxyethylmethacrylate (PHEMA) and polyvinylpyrrolidone (PVP) are discussed in relation to their recent use as intrastromal implants. The preliminary results dealing with a study on protein deposits on soft contact lenses in presence of a collyrium limiting the formation of such deposits are also reported. 1.

Alpinia katsumadai Extracts Inhibit Adhesion and Invasion of Campylobacter jejuni in Animal and Human Foetal Small Intestine Cell Lines.

PubMed

Pogačar, Maja Šikić; Klančnik, Anja; Bucar, Franz; Langerholc, Tomaž; Možina, Sonja Smole

2015-10-01

Alpinia katsumadai is used in traditional Chinese medicine for abdominal distention, pain, and diarrhoea. Campylobacter jejuni is the most common cause of bacterial food-borne diarrhoeal illnesses worldwide. Adhesion to gut epithelium is a prerequisite in its pathogenesis. The antimicrobial, cytotoxic, and anti-adhesive activities of a chemically characterised extract (SEE) and its residual material of hydrodistillation (hdSEE-R) from A. katsumadai seeds were evaluated against C. jejuni. Minimal inhibitory concentrations for SEE and hdSEE-R were 0.5 mg/mL and 0.25 mg/mL, respectively, and there was no cytotoxic influence in the anti-adhesion tests, as these were performed at much lower concentrations of these tested plant extracts. Adhesion of C. jejuni to pig (PSI) and human foetal (H4) small-intestine cell lines was significantly decreased at lower concentrations (0.2 to 50 µg/mL). In the same concentration range, the invasiveness of C. jejuni in PSI cells was reduced by 45% to 65% when they were treated with SEE or hdSEE-R. The hdSEE-R represents a bioactive waste with a high phenolic content and an anti-adhesive activity against C. jejuni and thus has the potential for use in pharmaceutical and food products. Copyright © 2015 John Wiley & Sons, Ltd.