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Sample records for bacteria biofilm formation

  1. Convergent evolution of hyperswarming leads to impaired biofilm formation in pathogenic bacteria

    PubMed Central

    van Ditmarsch, Dave; Boyle, Kerry E.; Sakhtah, Hassan; Oyler, Jennifer E.; Nadell, Carey D.; Dziel, ric; Dietrich, Lars E. P.; Xavier, Joao B.

    2013-01-01

    Most bacteria in nature live in surface-associated communities rather than planktonic populations. Nonetheless, how surface-associated environments shape bacterial evolutionary adaptation remains poorly understood. Here we show that subjecting Pseudomonas aeruginosa to repeated rounds of swarming, a collective form of surface migration, drives remarkable parallel evolution towards a hyperswarmer phenotype. In all independently evolved hyperswarmers, the reproducible hyperswarming phenotype is caused by parallel point mutations in a flagellar synthesis regulator, FleN, which locks the naturally mono-flagellated bacteria in a multi-flagellated state and confers a growth-rate independent advantage in swarming. Even though hyperswarmers outcompete the ancestral strain in swarming competitions, they are strongly outcompeted in biofilm formation, which is an essential trait for P. aeruginosa in environmental and clinical settings. The finding that evolution in swarming colonies reliably produces evolution of poor biofilm formers supports the existence of an evolutionary tradeoff between motility and biofilm formation. PMID:23954787

  2. [Interspecies interaction of bacteria and the formation of mixed (polymicrobial) biofilm].

    PubMed

    Maianskiĭ, A N; Chebotar', I V; Evteeva, N I; Rudneva, E I

    2012-01-01

    Natural biofilms rarely exist as monocultures. Usually they are formed from various microorganism species that interact with each other, have shared metabolites, strengthen the attachment of each other to the support substrate, provide expression of "foreign" genes etc. Material on factors and mechanisms that determine the formation of mixed (polymicrobial) biofilms is analyzed in the review. The significance of interspecies interaction between bacteria based on QS system signal autoinductors is underlined. Examples of humoral and contact communications between bacteria and eukaryotes including host cells are provided. Study of polymicrobial processes and their interaction with innate and adaptive immune response seems important for further development of medical microbiology (especially regarding chronic infectious diseases). PMID:22442979

  3. Molecular mechanisms involved in biofilm formation by food-associated bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofilms are complex bacterial communities adhering to a surface, an interface, or to each other and enclosed in an extracellular polymeric matrix. Genomic studies show that gene expression patterns of bacteria in biofilms differ from those of non-biofilm cells, indicating that there is a differen...

  4. Formation sphalerite (ZnS) deposits in natural biofilms of sulfate-reducing bacteria.

    SciTech Connect

    Labrenz, M.; Druschel, G. K.; Thomsen-Ebert, T.; Gilbert, B.; Welch, S. A.; Kemner, K. M.; Logan, G. A.; Summons, R. E.; De Stasio, G.; Bond, P. L.; Lai, B.; Kelly, S. D.; Banfield, J. F.; Univ. of Wisconsin at Madison; Australian Geological Survey Organisation; Diversions Scuba

    2000-12-01

    Abundant, micrometer-scale, spherical aggregates of 2- to 5-nanometer-diameter sphalerite (ZnS) particles formed within natural biofilms dominated by relatively aerotolerant sulfate-reducing bacteria of the family Desulfobacteriaceae. The biofilm zinc concentration is about 106 times that of associated groundwater (0.09 to 1.1 parts per million zinc). Sphalerite also concentrates arsenic (0.01 weight %) and selenium (0.004 weight %). The almost monomineralic product results from buffering of sulfide concentrations at low values by sphalerite precipitation. These results show how microbes control metal concentrations in groundwater- and wetland-based remediation systems and suggest biological routes for formation of some low-temperature ZnS deposits.

  5. Grapefruit juice and its furocoumarins inhibits autoinducer signaling and biofilm formation in bacteria.

    PubMed

    Girennavar, Basavaraj; Cepeda, Martha L; Soni, Kamlesh A; Vikram, Amit; Jesudhasan, Palmy; Jayaprakasha, G K; Pillai, Suresh D; Patil, Bhimanagouda S

    2008-07-15

    Cell-to-cell communications in bacteria mediated by small diffusible molecules termed as autoinducers (AI) are known to influence gene expression and pathogenicity. Oligopeptides and N-acylhomoserine lactones (AHL) are major AI molecules involved in intra-specific communication in gram-positive and gram-negative bacteria respectively, whereas boronated-diester molecules (AI-2) are involved in inter-specific communication among both gram-positive and gram-negative bacteria. Naturally occurring furocoumarins from grapefruit showed >95% inhibition of AI-1 and AI-2 activities based on the Vibrio harveyi based autoinducer bioassay. Grapefruit juice and furocoumarins also inhibited biofilm formation by Escherichia coli O157:H7, Salmonella typhimurium and Pseudomonas aeruginosa. These results suggest that grape fruit juice and furocoumarins could serve as a source to develop bacterial intervention strategies targeting microbial cell signaling processes. PMID:18504060

  6. Quorum quenching bacteria isolated from the sludge of a wastewater treatment plant and their application for controlling biofilm formation.

    PubMed

    Kim, A-Leum; Park, Son-Young; Lee, Chi-Ho; Lee, Chung-Hak; Lee, Jung-Kee

    2014-11-28

    Bacteria recognize changes in their population density by sensing the concentration of signal molecules, N-acyl-homoserine lactones (AHLs). AHL-mediated quorum sensing (QS) plays a key role in biofilm formation, so the interference of QS, referred to as quorum quenching (QQ), has received a great deal of attention. A QQ strategy can be applied to membrane bioreactors (MBRs) for advanced wastewater treatment to control biofouling. To isolate QQ bacteria that can inhibit biofilm formation, we isolated diverse AHL-degrading bacteria from a laboratory-scale MBR and sludge from real wastewater treatment plants. A total of 225 AHLdegrading bacteria were isolated from the sludge sample by enrichment culture. To identify the enzyme responsible for AHL degradation in QQ bacteria, AHL-degrading activities were analyzed using cell-free lysate, culture supernatant, and whole cells. Afipia sp. and Acinetobacter sp. strains produced the intracellular QQ enzyme, whereas Pseudomonas sp. and Micrococcus sp. produced the extracellular QQ enzyme that was most likely to produce AHLacylase. AHL-degrading activity was observed in whole-cell assay with the Microbacterium sp. and Rhodococcus sp. strains. There has been no report for AHL-degrading capability in the case of Streptococcus sp. and Afipia sp. strains. Finally, inhibition of biofilm formation by isolated QQ bacteria or enzymes was observed on glass slides and 96-well microtiter plates using crystal violet staining. QQ strains or enzymes not only inhibited initial biofilm development but also reduced established biofilms. PMID:25112313

  7. High-throughput screening of metal-N-heterocyclic carbene complexes against biofilm formation by pathogenic bacteria.

    PubMed

    Bernardi, Thierry; Badel, Stphanie; Mayer, Pascal; Groelly, Jrome; de Frmont, Pierre; Jacques, Batrice; Braunstein, Pierre; Teyssot, Marie-Laure; Gaulier, Christelle; Cisnetti, Federico; Gautier, Arnaud; Roland, Sylvain

    2014-06-01

    A set of molecules including a majority of metal-N-heterocyclic carbene (NHC) complexes (metal=Ag, Cu, and Au) and azolium salts were evaluated by high-throughput screening of their activity against biofilm formation associated with pathogenic bacteria. The anti-planktonic effects were compared in parallel. Representative biofilm-forming strains of various genera were selected (Listeria, Pseudomonas, Staphylococcus, and Escherichia). All the compounds were tested at 1 mg L(-1) by using the BioFilm Ring Test. An information score (IS, sum of the activities) and an activity score (AS, difference between anti-biofilm and anti-planktonic activity) were determined from normalized experimental values to classify the most active molecules against the panel of bacterial strains. With this method we identified lipophilic Ag(I) and Cu(I) complexes possessing aromatic groups on the NHC ligand as the most efficient at inhibiting biofilm formation. PMID:24729552

  8. Transitions in biofilm formation

    NASA Astrophysics Data System (ADS)

    Gordon, Vernita; Thatcher, Travis; Cooley, Benjamin

    2011-03-01

    Biofilms are multicellular, dynamic communities formed by interacting unicellular organisms bound to a surface. Forming a biofilm is a developmental process, characterized by sequential changes in gene expression and behavior as bacteria and yeast progress from discrete, free-swimming cells though stages that arrive at a mature biofilm. We are developing automated metrics to identify key transitions in early biofilm formation as cells attach to a surface, populate that surface, and adhere to each other to form early microcolonies. Our metrics use high-throughput tracking and analysis of microscopy movies to localize these transitions in space and time. Each of these transitions is associated with a loss of entropy in the bacterial system and, therefore, with biological activity that drives this loss of entropy. Better understanding of these transitions will allow automated determination of the strength and turn-on of attractive cell-surface and cell-cell interactions as biofilm development progresses.

  9. PATHOGENICITY OF BIOFILM BACTERIA

    EPA Science Inventory

    There is a paucity of information concerning any link between the microorganisms commonly found in biofilms of drinking water systems and their impacts on human health. For bacteria, culture-based techniques detect only a limited number of the total microorganisms associated wit...

  10. The Effects of Allium sativum Extracts on Biofilm Formation and Activities of Six Pathogenic Bacteria

    PubMed Central

    Mohsenipour, Zeinab; Hassanshahian, Mehdi

    2015-01-01

    Background: Garlic is considered a rich source of many compounds, which shows antimicrobial effects. The ability of microorganisms to adhere to both biotic and abiotic surfaces and to form biofilm is responsible for a number of diseases of chronic nature, demonstrating extremely high resistance to antibiotics. Bacterial biofilms are complex communities of sessile microorganisms, embedded in an extracellular matrix and irreversibly attached to various surfaces. Objectives: The present study evaluated the antimicrobial activity of Allium sativum extract against the biofilms of six pathogenic bacteria and their free-living forms. The clinical isolates in this study had not been studied in any other studies, especially in regard to biofilm disruption and inhibition of biofilm cell metabolic activity. Materials and Methods: Antimicrobial activities of A. sativum L. extracts (methanol and ethanol extracts) against planktonic forms of bacteria were determined using the disc diffusion method. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values were evaluated by a macrobroth dilution technique. The anti-biofilm effects were assessed by microtiter plate method. Results: The results showed that the A. sativum L. extract discs did not have any zone of inhibition for the tested bacteria. However, The MIC values of A. sativum L. extracts (0.078 - 2.5 mg/mL) confirmed the high ability of these extracts for inhibition of planktonic bacteria. A. sativum L. extracts were efficient to inhibit biofilm structures and the concentration of each extract had a direct relation with the inhibitory effect. Conclusions: Finally, it can be suggested that the extracts of this plant be applied as antimicrobial agents against these pathogens, particularly in biofilm forms. PMID:26464762

  11. Effect of Punica granatum L. Flower Water Extract on Five Common Oral Bacteria and Bacterial Biofilm Formation on Orthodontic Wire

    PubMed Central

    VAHID DASTJERDI, Elahe; ABDOLAZIMI, Zahra; GHAZANFARIAN, Marzieh; AMDJADI, Parisa; KAMALINEJAD, Mohammad; MAHBOUBI, Arash

    2014-01-01

    Background: Use of herbal extracts and essences as natural antibacterial compounds has become increasingly popular for the control of oral infectious diseases. Therefore, finding natural antimicrobial products with the lowest side effects seems necessary. The present study sought to assess the effect of Punica granatum L. water extract on five oral bacteria and bacterial biofilm formation on orthodontic wire. Methods: Antibacterial property of P. granatum L. water extract was primarily evaluated in brain heart infusion agar medium using well-plate method. The minimum inhibitory concentration and minimum bactericidal concentration were determined by macro-dilution method. The inhibitory effect on orthodontic wire bacterial biofilm formation was evaluated using viable cell count in biofilm medium. At the final phase, samples were fixed and analyzed by Scanning Electron Microscopy. Results: The growth inhibition zone diameter was proportional to the extract concentration. The water extract demonstrated the maximum antibacterial effect on Streptococcus sanguinis ATCC 10556 with a minimum inhibitory concentration of 6.25 mg/ml and maximum bactericidal effect on S. sanguinis ATCC 10556 and S. sobrinus ATCC 27607 with minimum bactericidal concentration of 25 mg/ml. The water extract decreased bacterial biofilm formation by S. sanguinis, S. sobrinus, S. salivarius, S. mutans ATCC 35608 and E. faecalis CIP 55142 by 93.7100%, 40.699.9%, 85.286.5%, 66.484.4% and 35.556.3% respectively. Conclusion: Punica granatum L. water extract had significant antibacterial properties against 5 oral bacteria and prevented orthodontic wire bacterial biofilm formation. However, further investigations are required to generalize these results to the clinical setting. PMID:26171362

  12. Calcium carbonate precipitation by heterotrophic bacteria isolated from biofilms formed on deteriorated ignimbrite stones: influence of calcium on EPS production and biofilm formation by these isolates.

    PubMed

    López-Moreno, Angélica; Sepúlveda-Sánchez, José David; Mercedes Alonso Guzmán, Elia Mercedes; Le Borgne, Sylvie

    2014-01-01

    Heterotrophic CaCO3-precipitating bacteria were isolated from biofilms on deteriorated ignimbrites, siliceous acidic rocks, from Morelia Cathedral (Mexico) and identified as Enterobacter cancerogenus (22e), Bacillus sp. (32a) and Bacillus subtilis (52g). In solid medium, 22e and 32a precipitated calcite and vaterite while 52g produced calcite. Urease activity was detected in these isolates and CaCO3 precipitation increased in the presence of urea in the liquid medium. In the presence of calcium, EPS production decreased in 22e and 32a and increased in 52g. Under laboratory conditions, ignimbrite colonization by these isolates only occurred in the presence of calcium and no CaCO3 was precipitated. Calcium may therefore be important for biofilm formation on stones. The importance of the type of stone, here a siliceous stone, on biological colonization is emphasized. This calcium effect has not been reported on calcareous materials. The importance of the effect of calcium on EPS production and biofilm formation is discussed in relation to other applications of CaCO3 precipitation by bacteria. PMID:24689777

  13. Effect of algae and plant lectins on planktonic growth and biofilm formation in clinically relevant bacteria and yeasts.

    PubMed

    Vasconcelos, Mayron Alves; Arruda, Francisco Vassiliepe Sousa; Carneiro, Victor Alves; Silva, Helton Colares; Nascimento, Kyria Santiago; Sampaio, Alexandre Holanda; Cavada, Benildo; Teixeira, Edson Holanda; Henriques, Mariana; Pereira, Maria Olivia

    2014-01-01

    This study aimed to evaluate the abilities of plant and algae lectins to inhibit planktonic growth and biofilm formation in bacteria and yeasts. Initially, ten lectins were tested on Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella oxytoca, Pseudomonas aeruginosa, Candida albicans, and C. tropicalis at concentrations of 31.25 to 250  μ g/mL. The lectins from Cratylia floribunda (CFL), Vatairea macrocarpa (VML), Bauhinia bauhinioides (BBL), Bryothamnion seaforthii (BSL), and Hypnea musciformis (HML) showed activities against at least one microorganism. Biofilm formation in the presence of the lectins was also evaluated; after 24 h of incubation with the lectins, the biofilms were analyzed by quantifying the biomass (by crystal violet staining) and by enumerating the viable cells (colony-forming units). The lectins reduced the biofilm biomass and/or the number of viable cells to differing degrees depending on the microorganism tested, demonstrating the different characteristics of the lectins. These findings indicate that the lectins tested in this study may be natural alternative antimicrobial agents; however, further studies are required to better elucidate the functional use of these proteins. PMID:24982871

  14. 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

  15. Artemisia princeps Inhibits Biofilm Formation and Virulence-Factor Expression of Antibiotic-Resistant Bacteria

    PubMed Central

    Choi, Na-Young; Kang, Sun-Young; Kim, Kang-Ju

    2015-01-01

    In this study, we used ethanol extract of A. princeps and investigated its antibacterial effects against MRSA. Ethanol extract of A. princeps significantly inhibited MRSA growth and organic acid production during glucose metabolism at concentrations greater than 1 mg/mL (P < 0.05). MRSA biofilm formation was observed using scanning electron microscopy (SEM) and safranin staining. A. princeps extract was found to inhibit MRSA biofilm formation at concentrations higher than 2 mg/mL significantly (P < 0.05). Bactericidal effects of the A. princeps were observed using confocal laser microscopy, which showed that A. princeps was bactericidal in a dose-dependent manner. Using real-time PCR, expression of mecA, an antibiotic-resistance gene of MRSA, was observed, along with that of sea, agrA, and sarA. A. princeps significantly inhibited mecA, sea, agrA, and sarA, mRNA expression at the concentrations greater than 1 mg/mL (P < 0.05). The phytochemical analysis of A. princeps showed a relatively high content of organic acids and glycosides. The results of this study suggest that the ethanol extract of A. princeps may inhibit proliferation, acid production, biofilm formation, and virulence gene expressions of MRSA, which may be related to organic acids and glycosides, the major components in the extract. PMID:26247012

  16. Identification of lactobacilli with inhibitory effect on biofilm formation by pathogenic bacteria on stainless steel surfaces.

    PubMed

    Ait Ouali, Fatma; Al Kassaa, Imad; Cudennec, Benoit; Abdallah, Marwan; Bendali, Farida; Sadoun, Djamila; Chihib, Nour-Eddine; Drider, Djamel

    2014-11-17

    Two hundred and thirty individual clones of microorganisms were recovered from milk tanks and milking machine surfaces at two distinct farms (Bejaja City, Algeria). Of these clones, 130 were identified as lactic acid bacteria (LAB). In addition Escherichia coli, Salmonella, Staphylococcus aureus and Pseudomonas aeruginosa species were identified in the remaining 100 isolates-spoilage isolate. These isolates were assayed for ability to form biofilms. S. aureus, Lactobacillus brevis strains LB1F2, LB14F1 and LB15F1, and Lactobacillus pentosus strains LB2F2 and LB3F2 were identified as the best biofilm formers. Besides, these LAB isolates were able to produce proteinaceous substances with antagonism against the aforementioned spoilage isolates, when grown in MRS or TSB-YE media. During the screening, L. pentosus LB3F2 exhibited the highest antibacterial activity when grown in TSB-YE medium at 30 C. Additionally, L. pentosus LB3F2 was able to strongly hamper the adhesion of S. aureus SA3 on abiotic surfaces as polystyrene and stainless steel slides. LAB isolates did not show any hemolytic activity and all of them were sensitive to different families of antibiotic tested. It should be pointed out that LB3F2 isolate was not cytotoxic on the intestinal cells but could stimulate their metabolic activity. This report unveiled the potential of LB1F2, LB14F1, LB15F1, LB2F2, and LB3F2 isolates to be used as natural barrier or competitive exclusion organism in the food processing sector as well as a positive biofilm forming bacteria. PMID:25261829

  17. Polyphenolic Extract from Maple Syrup Potentiates Antibiotic Susceptibility and Reduces Biofilm Formation of Pathogenic Bacteria

    PubMed Central

    Maisuria, Vimal B.; Hosseinidoust, Zeinab

    2015-01-01

    Phenolic compounds are believed to be promising candidates as complementary therapeutics. Maple syrup, prepared by concentrating the sap from the North American maple tree, is a rich source of natural and process-derived phenolic compounds. In this work, we report the antimicrobial activity of a phenolic-rich maple syrup extract (PRMSE). PRMSE exhibited antimicrobial activity as well as strong synergistic interaction with selected antibiotics against Gram-negative clinical strains of Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa. Among the phenolic constituents of PRMSE, catechol exhibited strong synergy with antibiotics as well as with other phenolic components of PRMSE against bacterial growth. At sublethal concentrations, PRMSE and catechol efficiently reduced biofilm formation and increased the susceptibility of bacterial biofilms to antibiotics. In an effort to elucidate the mechanism for the observed synergy with antibiotics, PRMSE was found to increase outer membrane permeability of all bacterial strains and effectively inhibit efflux pump activity. Furthermore, transcriptome analysis revealed that PRMSE significantly repressed multiple-drug resistance genes as well as genes associated with motility, adhesion, biofilm formation, and virulence. Overall, this study provides a proof of concept and starting point for investigating the molecular mechanism of the reported increase in bacterial antibiotic susceptibility in the presence of PRMSE. PMID:25819960

  18. Polyphenolic extract from maple syrup potentiates antibiotic susceptibility and reduces biofilm formation of pathogenic bacteria.

    PubMed

    Maisuria, Vimal B; Hosseinidoust, Zeinab; Tufenkji, Nathalie

    2015-06-01

    Phenolic compounds are believed to be promising candidates as complementary therapeutics. Maple syrup, prepared by concentrating the sap from the North American maple tree, is a rich source of natural and process-derived phenolic compounds. In this work, we report the antimicrobial activity of a phenolic-rich maple syrup extract (PRMSE). PRMSE exhibited antimicrobial activity as well as strong synergistic interaction with selected antibiotics against Gram-negative clinical strains of Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa. Among the phenolic constituents of PRMSE, catechol exhibited strong synergy with antibiotics as well as with other phenolic components of PRMSE against bacterial growth. At sublethal concentrations, PRMSE and catechol efficiently reduced biofilm formation and increased the susceptibility of bacterial biofilms to antibiotics. In an effort to elucidate the mechanism for the observed synergy with antibiotics, PRMSE was found to increase outer membrane permeability of all bacterial strains and effectively inhibit efflux pump activity. Furthermore, transcriptome analysis revealed that PRMSE significantly repressed multiple-drug resistance genes as well as genes associated with motility, adhesion, biofilm formation, and virulence. Overall, this study provides a proof of concept and starting point for investigating the molecular mechanism of the reported increase in bacterial antibiotic susceptibility in the presence of PRMSE. PMID:25819960

  19. Biofilm formation by Clostridium difficile

    PubMed Central

    Dapa, Tanja; Unnikrishnan, Meera

    2013-01-01

    Clostridium difficile infection (CDI) is a major healthcare-associated disease worldwide. Recurring infections and increasing antibiotic resistance have complicated treatment of CDI. While C. difficile spores are important for transmission and persistence of CDI, other factors such as gut colonization and formation of bacterial communities in the gut may also contribute to pathogenesis and persistence, but have not been well investigated. Recently, we reported that important clinical C. difficile strains are able to form composite biofilms in vitro. C. difficile biofilm formation is a complex process, modulated by several different factors, including cell surface components and regulators. We also reported that bacteria within biofilms are more resistant to high concentrations of vancomycin, the antibiotic of choice for treatment of CDI. Here we summarize our recent findings and discuss the implications of biofilm formation by this anaerobic gut pathogen in disease pathogenesis and treatment. PMID:23892245

  20. Biofilm formation in Streptococcus pneumoniae

    PubMed Central

    Domenech, Mirian; García, Ernesto; Moscoso, Miriam

    2012-01-01

    Summary Biofilm‐grown bacteria are refractory to antimicrobial agents and show an increased capacity to evade the host immune system. In recent years, studies have begun on biofilm formation by Streptococcus pneumoniae, an important human pathogen, using a variety of in vitro model systems. The bacterial cells in these biofilms are held together by an extracellular matrix composed of DNA, proteins and, possibly, polysaccharide(s). Although neither the precise nature of these proteins nor the composition of the putative polysaccharide(s) is clear, it is known that choline‐binding proteins are required for successful biofilm formation. Further, many genes appear to be involved, although the role of each appears to vary when biofilms are produced in batch or continuous culture. Prophylactic and therapeutic measures need to be developed to fight S. pneumoniae biofilm formation. However, much care needs to be taken when choosing strains for such studies because different S. pneumoniae isolates can show remarkable genomic differences. Multispecies and in vivo biofilm models must also be developed to provide a more complete understanding of biofilm formation and maintenance. PMID:21906265

  1. Combined Effects of Curcumin and (-)-Epigallocatechin Gallate on Inhibition of N-Acylhomoserine Lactone-Mediated Biofilm Formation in Wastewater Bacteria from Membrane Bioreactor.

    PubMed

    Lade, Harshad; Paul, Diby; Kweon, Ji Hyang

    2015-11-28

    This work investigated the potential of curcumin (CCM) and (-)-epigallocatechin gallate (EGCG) to inhibit N-acyl homoserine lactone (AHL)-mediated biofilm formation in gramnegative bacteria from membrane bioreactor (MBR) activated sludge. The minimum inhibitory concentrations (MICs) of CCM alone against all the tested bacteria were 200-350 ?g/ml, whereas those for EGCG were 300-600 ?g/ml. Biofilm formation at one-half MICs indicated that CCM and EGCG alone respectively inhibited 52-68% and 59-78% of biofilm formation among all the tested bacteria. However, their combination resulted in 95-99% of biofilm reduction. Quorum sensing inhibition (QSI) assay with known biosensor strains demonstrated that CCM inhibited the expression of C4 and C6 homoserine lactones (HSLs)-mediated phenotypes, whereas EGCG inhibited C4, C6, and C10 HSLs-based phenotypes. The Center for Disease Control biofilm reactor containing a multispecies culture of nine bacteria with onehalf MIC of CCM (150 ?g/ml) and EGCG (275 ?g/ml) showed 17 and 14 ?g/cm(2) of extracellular polymeric substances (EPS) on polyvinylidene fluoride membrane surface, whereas their combination (100 ?g/ml of each) exhibited much lower EPS content (3 ?g/cm(2)). Confocal laser scanning microscopy observations also illustrated that the combination of compounds tremendously reduced the biofilm thickness. The combined effect of CCM with EGCG clearly reveals for the first time the enhanced inhibition of AHL-mediated biofilm formation in bacteria from activated sludge. Thus, such combined natural QSI approach could be used for the inhibition of membrane biofouling in MBRs treating wastewaters. PMID:26139614

  2. Emergent Bacteria in Cystic Fibrosis: In Vitro Biofilm Formation and Resilience under Variable Oxygen Conditions

    PubMed Central

    Lopes, Susana P.; Azevedo, Nuno F.; Pereira, Maria O.

    2014-01-01

    Concurrent to conventional bacterial pathogens, unusual microbes are emerging from cystic fibrosis (CF) airways. Nonetheless, little is known about the contribution of these newly microbes to the resilience of CF-associated biofilms, particularly under variable-oxygen concentrations that are known to occur in vivo in the mucus of CF patients. Two CF-emergent bacterial species, Inquilinus limosus and Dolosigranulum pigrum, and the major pathogen Pseudomonas aeruginosa were studied in terms of biofilm development and antibiotic susceptibilities under in vitro atmospheres with different oxygen availabilities. All species were able to develop in vitro biofilms under different oxygen-available environments, with D. pigrum accumulating high amounts of biomass and respiratory activities. When established, biofilms were of difficult eradication, with antibiotics losing their effectiveness in comparison with the corresponding planktonic populations. Surprisingly, biofilms of each emergent organism displayed multidrug resistance under aerobic environments, enduring even in low-oxygen atmospheres. This study suggests a potential prospect on the impact of nonconventional organisms I. limosus and D. pigrum on CF lung infections, demonstrating capacity to adapt to biofilm mode of life under restricted-oxygen atmospheres resembling CF airways, which may ultimately endanger the efficacy of currently used antibiotic regimens. PMID:24868541

  3. Clay-Bacteria Systems and Biofilm Production

    NASA Astrophysics Data System (ADS)

    Steiner, J.; Alimova, A.; Katz, A.; Steiner, N.; Rudolph, E.; Gottlieb, P.

    2007-12-01

    Soil clots and the aerosol transport of bacteria and spores are promoted by the formation of biofilms (bacteria cells in an extracellular polymeric matrix). Biofilms protect microorganisms by promoting adhesion to both organic and inorganic surfaces. Time series experiments on bacteria-clay suspensions demonstrate that biofilm growth is catalyzed by the presence of hectorite in minimal growth media for the studied species: Gram negatives (Pseudomonas syringae and Escherichia coli,) and Gram positives (Staphylococcus aureus and Bacillus subtilis). Soil organisms (P. syringae, B. subtilis) and organisms found in the human population (E. coli, S. aureus) are both used to demonstrate the general applicability of clay involvement. Fluorescent images of the biofilms are acquired by staining with propidium iodide, a component of the BacLightTM Live/Dead bacterial viability staining kit (Molecular Probes, Eugene, OR). The evolving polysaccharide-rich biofilm reacts with the clay interlayer site causing a complex substitution of the two-water hectorite interlayer with polysaccharide. The result is often a three-peak composite of the (001) x-ray diffraction maxima resulting from polysaccharide-expanded clays and an organic-driven contraction of a subset of the clays in the reaction medium. X-ray diffractograms reveal that the expanded set creates a broad maximum with clay subsets at 1.84 nm and 1.41 nm interlayer spacings as approximated by a least squares double Lorentzian fit, and a smaller shoulder at larger 2q, deriving from a contraction of the interlayer spacing. Washing with chlorox removes organic material from the contracted clay and creates a 1-water hectorite single peak in place of the double peak. The clay response can be used as an indirect indicator of biofilm in an environmental system.

  4. Biofilm formation by vaginal Lactobacillus in vivo.

    PubMed

    Ventolini, G; Mitchell, E; Salazar, M

    2015-05-01

    Biofilm formation by nonpathogenic bacteria is responsible for their stable maintenance in vivo ecosystems as it promotes long-term permanence on the host's vaginal mucosa. Biofilm formation by Lactobacilli has been reported in vitro but not in vivo. We hypothesize the presence of biofilm formation in vivo could be also documented by microscope photographs (MP) of wet mounts obtained from uninfected vaginal samples satisfying rigorous scientific identification criteria. We analyzed 400 MP from our database, and we were able to determine that 12 MP from 6 different patients contained clues of the formation of biofilm by Lactobacilli. The most probable lactobacillus involved is presumed to be Lactobacillus jensenii. The documentation of biofilm formation by vaginal Lactobacilli at fresh wet mount preparation is significant and has several important clinical preventive and therapeutic implications. PMID:25725906

  5. Regulation of flagellar motility during biofilm formation

    PubMed Central

    Guttenplan, Sarah B.; Kearns, Daniel B.

    2013-01-01

    Many bacteria swim in liquid or swarm over solid surfaces by synthesizing rotary flagella. The same bacteria that are motile also commonly form non-motile multicellular aggregates held together by an extracellular matrix called biofilms. Biofilms are an important part of the lifestyle of pathogenic bacteria and it is assumed that there is a motility-to-biofilm transition wherein the inhibition of motility promotes biofilm formation. The transition is largely inferred from regulatory mutants that reveal the opposite regulation of the two phenotypes. Here we review the regulation of motility during biofilm formation in Bacillus, Pseudomonas, Vibrio, and Escherichia, and we conclude that the motility-to-biofilm transition, if necessary, likely involves two steps. In the short term, flagella are functionally regulated to either inhibit rotation or modulate the basal flagellar reversal frequency. Over the long term, flagellar gene transcription is inhibited and in the absence of de novo synthesis, flagella are likely diluted to extinction through growth. Both short term and long term control is likely important to the motility-to-biofilm transition to stabilize aggregates and optimize resource investment. We emphasize the newly discovered classes of flagellar functional regulators and speculate that others await discovery in the context of biofilm formation. PMID:23480406

  6. Biofilm formation in an ice cream plant.

    PubMed

    Gunduz, Gulten Tiryaki; Tuncel, Gunnur

    2006-01-01

    The sites of biofilm formation in an ice cream plant were investigated by sampling both the production line and the environment. Experiments were carried out twice within a 20-day period. First, stainless steel coupons were fixed to surfaces adjacent to food contact surfaces, the floor drains and the doormat. They were taken for the analysis of biofilm at three different production stages. Then, biofilm forming bacteria were enumerated and also presence of Listeria monocytogenes was monitored. Biofilm forming isolates were selected on the basis of colony morphology and Gram's reaction; Gram negative cocci and rod, Gram positive cocci and spore forming isolates were identified. Most of the biofilm formations were seen on the conveyor belt of a packaging machine 8 h after the beginning of the production, 6.5 x 10(3) cfu cm(-2). Most of the Gram negative bacteria identified belong to Enterobacteriaceae family such as Proteus, Enterobacter, Citrobacter, Shigella, Escherichia, Edwardsiella. The other Gram negative microflora included Aeromonas, Plesiomonas, Moraxella, Pseudomonas or Alcaligenes spp. were also isolated. Gram positive microflora of the ice cream plant included Staphyloccus, Bacillus, Listeria and lactic acid bacteria such as Streptococcus, Leuconostoc or Pediococcus spp. The results from this study highlighted the problems of spread of pathogens like Listeria and Shigella and spoilage bacteria. In the development of cleaning and disinfection procedures in ice cream plants, an awareness of these biofilm-forming bacteria is essential for the ice cream plants. PMID:16779628

  7. Spermine impairs biofilm formation by Neisseria gonorrhoeae

    PubMed Central

    Goytia, Maira; Dhulipala, Vijaya L.; Shafer, William M.

    2013-01-01

    Neisseria gonorrhoeae is a strict human pathogen that causes the sexually transmitted infection termed gonorrhea. Recent reports indicate that gonococci can form a biofilm in vivo and under laboratory conditions. It is unclear, however, if formation of such biofilms or their dispersal are influenced by host factors that would be encountered during infection. In this respect, physiological levels of polyamines have been reported to influence biofilm structures formed by other Gram-negative bacteria as well those formed by Grampositive bacteria and can cause dispersal of a biofilm formed by Bacillus subtilis. Based on these reports, we examined the influence of polyamines on gonococcal biofilm formation and their dispersal. We now report that physiological levels of certain polyamines, notably spermine, can significantly decrease the capacity of gonococci to form a biofilm, but do not cause dispersal of a pre-formed biofilm. In the context of natural gonococcal infection, the presence of physiological levels of spermine may be antagonistic for gonococci to form a biofilm and this may be of importance in the spread of the pathogen from a localized region. PMID:23506248

  8. A new biofilm-associated colicin with increased efficiency against biofilm bacteria

    PubMed Central

    Rendueles, Olaya; Beloin, Christophe; Latour-Lambert, Patricia; Ghigo, Jean-Marc

    2014-01-01

    Formation of bacterial biofilm communities leads to profound physiological modifications and increased physical and metabolic exchanges between bacteria. It was previously shown that bioactive molecules produced within the biofilm environment contribute to bacterial interactions. Here we describe new pore-forming colicin R, specifically produced in biofilms formed by the natural isolate Escherichia coli ROAR029 but that cannot be detected under planktonic culture conditions. We demonstrate that an increased SOS stress response within mature biofilms induces SOS-dependent colicin R expression. We provide evidence that colicin R displays increased activity against E. coli strains that have a reduced lipopolysaccharide length, such as the pathogenic enteroaggregative E. coli LF82 clinical isolate, therefore pointing to lipopolysaccharide size as an important determinant for resistance to colicins. We show that colicin R toxicity toward E. coli LF82 is increased under biofilm conditions compared with planktonic susceptibility and that release of colicin R confers a strong competitive advantage in mixed biofilms by rapidly outcompeting sensitive neighboring bacteria. This work identifies the first biofilm-associated colicin that preferentially targets biofilm bacteria. Furthermore, it indicates that the study of antagonistic molecules produced in biofilm and multispecies contexts could reveal unsuspected, ecologically relevant bacterial interactions influencing population dynamics in natural environments. PMID:24451204

  9. Dual-species biofilms formation by Escherichia coli O157:H7 and environmental bacteria isolated from fresh-cut processing plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofilm formation is a mechanism adapted by many microorganisms that enhances the survival in stressful environments. In food processing facilities, bacterial strains with strong biofilm forming capacities are more likely to survive the daily cleaning and disinfection. Foodborne bacterial pathogens,...

  10. Physicochemical regulation of biofilm formation

    PubMed Central

    Renner, Lars D.; Weibel, Douglas B.

    2011-01-01

    This article reviews the physical and chemical constraints of environments on biofilm formation. We provide a perspective on how materials science and engineering can address fundamental questions and unmet technological challenges in this area of microbiology, such as biofilm prevention. Specifically, we discuss three factors that impact the development and organization of bacterial communities. (1) Physical properties of surfaces regulate cell attachment and physiology and affect early stages of biofilm formation. (2) Chemical properties influence the adhesion of cells to surfaces and their development into biofilms and communities. (3) Chemical communication between cells attenuates growth and influences the organization of communities. Mechanisms of spatial and temporal confinement control the dimensions of communities and the diffusion path length for chemical communication between biofilms, which, in turn, influences biofilm phenotypes. Armed with a detailed understanding of biofilm formation, researchers are applying the tools and techniques of materials science and engineering to revolutionize the study and control of bacterial communities growing at interfaces. PMID:22125358

  11. Crenarchaeal Biofilm Formation under Extreme Conditions

    PubMed Central

    Koerdt, Andrea; Gödeke, Julia; Berger, Jürgen; Thormann, Kai M.; Albers, Sonja-Verena

    2010-01-01

    Background Biofilm formation has been studied in much detail for a variety of bacterial species, as it plays a major role in the pathogenicity of bacteria. However, only limited information is available for the development of archaeal communities that are frequently found in many natural environments. Methodology We have analyzed biofilm formation in three closely related hyperthermophilic crenarchaeotes: Sulfolobus acidocaldarius, S. solfataricus and S. tokodaii. We established a microtitre plate assay adapted to high temperatures to determine how pH and temperature influence biofilm formation in these organisms. Biofilm analysis by confocal laser scanning microscopy demonstrated that the three strains form very different communities ranging from simple carpet-like structures in S. solfataricus to high density tower-like structures in S. acidocaldarius in static systems. Lectin staining indicated that all three strains produced extracellular polysaccharides containing glucose, galactose, mannose and N-acetylglucosamine once biofilm formation was initiated. While flagella mutants had no phenotype in two days old static biofilms of S. solfataricus, a UV-induced pili deletion mutant showed decreased attachment of cells. Conclusion The study gives first insights into formation and development of crenarchaeal biofilms in extreme environments. PMID:21124788

  12. Automatic quantification of early transition points in biofilm formation

    NASA Astrophysics Data System (ADS)

    Thatcher, Travis; Bienvenu, Samuel; Strain, Shinji; Gordon, Vernita

    2010-10-01

    Biofilms are multicellular, dynamic communities of interacting single-cell organisms, like bacteria. Biofilms are responsible for many infectious diseases as well as for significant damage in industrial settings, yet many aspects of biofilm formation are not well understood. Identifying and quantifying the interactions leading to biofilm formation will not only be important for understanding the basic science of these and other multicellular systems, but it will also be essential for designing targeted strategies to prevent or disrupt biofilms. In particular, it is not clear what physical interactions, and corresponding biological mechanisms, are responsible for the early steps in biofilm formation. Because of this, we are developing high-throughput software techniques to analyze micrograph movies of biofilm formation, from attachment to surfaces through the development of microcolonies. This work will focus on developing software tools to identify and quantify key steps in biofilm formation, first in non-chemotacting systems and later in chemotacting (and autotacting) systems.

  13. Spaceflight promotes biofilm formation by Pseudomonas aeruginosa.

    PubMed

    Kim, Wooseong; Tengra, Farah K; Young, Zachary; Shong, Jasmine; Marchand, Nicholas; Chan, Hon Kit; Pangule, Ravindra C; Parra, Macarena; Dordick, Jonathan S; Plawsky, Joel L; Collins, Cynthia H

    2013-01-01

    Understanding the effects of spaceflight on microbial communities is crucial for the success of long-term, manned space missions. Surface-associated bacterial communities, known as biofilms, were abundant on the Mir space station and continue to be a challenge on the International Space Station. The health and safety hazards linked to the development of biofilms are of particular concern due to the suppression of immune function observed during spaceflight. While planktonic cultures of microbes have indicated that spaceflight can lead to increases in growth and virulence, the effects of spaceflight on biofilm development and physiology remain unclear. To address this issue, Pseudomonas aeruginosa was cultured during two Space Shuttle Atlantis missions: STS-132 and STS-135, and the biofilms formed during spaceflight were characterized. Spaceflight was observed to increase the number of viable cells, biofilm biomass, and thickness relative to normal gravity controls. Moreover, the biofilms formed during spaceflight exhibited a column-and-canopy structure that has not been observed on Earth. The increase in the amount of biofilms and the formation of the novel architecture during spaceflight were observed to be independent of carbon source and phosphate concentrations in the media. However, flagella-driven motility was shown to be essential for the formation of this biofilm architecture during spaceflight. These findings represent the first evidence that spaceflight affects community-level behaviors of bacteria and highlight the importance of understanding how both harmful and beneficial human-microbe interactions may be altered during spaceflight. PMID:23658630

  14. Interactions and transitions in biofilm formation

    NASA Astrophysics Data System (ADS)

    Gordon, Vernita; Colvin, Kelly; Conrad, Jacinta; Gibiansky, Maxsim; Jin, Fan; Parsek, Matthew; Wong, Gerard

    2010-10-01

    Biofilms are multicellular, interacting communities of intrinsically-unicellular organisms that grow on surfaces. As such, they are fascinating model systems for multicellularity. They are also of great practical importance, since biofilms damage a variety of industrial infrastructure and are the cause of most persistent, antibiotic-resistant infections. In natural settings, most bacteria are found in biofilms. To initiate a biofilm, planktonic, free-swimming bacteria attach to a surface and then undergo a series of phenotypic changes as that adhesion becomes irreversible and the surface is populated, first by discrete bacteria, and then bacteria growing in dense clusters, ``microcolonies.'' Both adhesion to a surface and adhesion to other cells are associated with adhesive properties of cell-produced extracellular polysaccharides (EPSs). Using laser tweezers to test cell aggregation and aggregate stability, in combination with gene expression assays and gene-knockouts, we show the importance of one EPS, pel, for early cell aggregation. We also use automated bacteria-identification and --tracking software algorithims to identify and quantify key transitions early in biofilm formation.

  15. Cadmium Modulates Biofilm Formation by Staphylococcus epidermidis

    PubMed Central

    Wu, Xueqing; Santos, Regiane R.; Fink-Gremmels, Johanna

    2015-01-01

    The aim of the study was to evaluate the effect of cadmium exposure on Staphylococcus epidermidis (ATCC 35984) biofilm formation. Bacteria were cultured in the absence or presence of different concentrations (0–50 µM) of cadmium. Biofilm formation and bacterial viability were assessed. Quantitative Real Time-PCR (qRT-PCR) was used to determine the mRNA expression of molecular markers of S. epidermidis biofilm formation and dispersion. S. epidermidis biofilm formation was stimulated (p < 0.001) by 1.56 and 3.13 µM cadmium. Confocal laser scanning microscopy (CLSM) analysis confirmed an increase in biofilm thickness (23 and 22 µm, versus 17.8 µm in the controls) after exposure to 1.56 or 3.13 µM cadmium, respectively. qRT-PCR was performed showing the up-regulation of atlE, embp, aap, icaA and icaB after exposure to 3.13 µM cadmium. Taken together, these findings show that cadmium at low, sub-toxic concentrations acts as inducer of S. epidermidis biofilm formation. PMID:25749322

  16. Cadmium modulates biofilm formation by Staphylococcus epidermidis.

    PubMed

    Wu, Xueqing; Santos, Regiane R; Fink-Gremmels, Johanna

    2015-03-01

    The aim of the study was to evaluate the effect of cadmium exposure on Staphylococcus epidermidis (ATCC 35984) biofilm formation. Bacteria were cultured in the absence or presence of different concentrations (0-50 µM) of cadmium. Biofilm formation and bacterial viability were assessed. Quantitative Real Time-PCR (qRT-PCR) was used to determine the mRNA expression of molecular markers of S. epidermidis biofilm formation and dispersion. S. epidermidis biofilm formation was stimulated (p<0.001) by 1.56 and 3.13 µM cadmium. Confocal laser scanning microscopy (CLSM) analysis confirmed an increase in biofilm thickness (23 and 22 µm, versus 17.8 µm in the controls) after exposure to 1.56 or 3.13 µM cadmium, respectively. qRT-PCR was performed showing the up-regulation of atlE, embp, aap, icaA and icaB after exposure to 3.13 µM cadmium. Taken together, these findings show that cadmium at low, sub-toxic concentrations acts as inducer of S. epidermidis biofilm formation. PMID:25749322

  17. Physics of biofilms: the initial stages of biofilm formation and dynamics

    NASA Astrophysics Data System (ADS)

    Lambert, Guillaume; Bergman, Andrew; Zhang, Qiucen; Bortz, David; Austin, Robert

    2014-04-01

    One of the physiological responses of bacteria to external stress is to assemble into a biofilm. The formation of a biofilm greatly increases a bacterial population's resistance to a hostile environment by shielding cells, for example, from antibiotics. In this paper, we describe the conditions necessary for the emergence of biofilms in natural environments and relate them to the emergence of biofilm formation inside microfluidic devices. We show that competing species of Escherichia coli bacteria form biofilms to spatially segregate themselves in response to starvation stress, and use in situ methods to characterize the physical properties of the biofilms. Finally, we develop a microfluidic platform to study the inter-species interactions and show how biofilm-mediated genetic interactions can improve a species’ resistance to external stress.

  18. Biofilm formation and microbial corrosion

    SciTech Connect

    Goldstein, R.; Porcella, D.

    1992-07-01

    Biofilms-colonies of microorganisms growing on surfaces - can greatly accelerate the corrosion rates of metals and alloys in utility water systems. Fundamental EPRI research is showing how mechanisms of biofilm formation, interactions between bacterial species, and metabolic activities control such biofilm properties as corrosive potential This research is identifying methods to control biofilm development and prevent microbially influenced corrosion. The results should also apply to the control of other processes involving biological consortia, including the bioremediation of contaminated groundwater and soil and the biodesulfurization of coal.

  19. IMPACTS OF BIOFILM FORMATION ON CELLULOSE FERMENTATION

    SciTech Connect

    Leschine, Susan

    2009-10-31

    This project addressed four major areas of investigation: i) characterization of formation of Cellulomonas uda biofilms on cellulose; ii) characterization of Clostridium phytofermentans biofilm development; colonization of cellulose and its regulation; iii) characterization of Thermobifida fusca biofilm development; colonization of cellulose and its regulation; and iii) description of the architecture of mature C. uda, C. phytofermentans, and T. fusca biofilms. This research is aimed at advancing understanding of biofilm formation and other complex processes involved in the degradation of the abundant cellulosic biomass, and the biology of the microbes involved. Information obtained from these studies is invaluable in the development of practical applications, such as the single-step bioconversion of cellulose-containing residues to fuels and other bioproducts. Our results have clearly shown that cellulose-decomposing microbes rapidly colonize cellulose and form complex structures typical of biofilms. Furthermore, our observations suggest that, as cells multiply on nutritive surfaces during biofilms formation, dramatic cell morphological changes occur. We speculated that morphological changes, which involve a transition from rod-shaped cells to more rounded forms, might be more apparent in a filamentous microbe. In order to test this hypothesis, we included in our research a study of biofilm formation by T. fusca, a thermophilic cellulolytic actinomycete commonly found in compost. The cellulase system of T. fusca has been extensively detailed through the work of David Wilson and colleagues at Cornell, and also, genome sequence of a T. fusca strain has been determine by the DOE Joint Genome Institute. Thus, T. fusca is an excellent subject for studies of biofilm development and its potential impacts on cellulose degradation. We also completed a study of the chitinase system of C. uda. This work provided essential background information for understanding how C. uda colonizes and degrades insoluble substrates. Major accomplishments of the project include: • Development of media containing dialysis tubing (described by the manufacturer as “regenerated cellulose”) as sole carbon and energy source and a nutritive surface for the growth of cellulolytic bacteria, and development of various microscopic methods to image biofilms on dialysis tubing. • Demonstration that cultures of C. phytofermentans, an obligate anaerobe, C. uda, a facultative aerobe, and T. fusca, a filamentous aerobe, formed microbial communities on the surface of dialysis tubing, which possessed architectural features and functional characteristics typical of biofilms. • Demonstration that biofilm formation on the nutritive surface, cellulose, involves a complex developmental processes, including colonization of dialysis tubing, formation of cell clusters attached to the nutritive surface, cell morphological changes, formation of complex structures embedded in extracellular polymeric matrices, and dispersal of biofilm communities as the nutritive surface is degraded. • Determination of surface specificity and regulatory aspects of biofilm formation by C. phytofermentans, C. uda, and T. fusca. • Demonstration that biofilm formation by T. fusca forms an integral part of the life cycle of this filamentous cellulolytic bacterium, including studies on the role of mycelial pellet formation in the T. fusca life cycle and a comparison of mycelial pellets to surface-attached T. fusca biofilms. • Characterization of T. fusca biofilm EPS, including demonstration of a functional role for EPS constituents. • Correlation of T. fusca developmental life cycle and cellulase gene expression.

  20. Oh What a Tangled Biofilm Web Bacteria Weave

    MedlinePLUS

    ... Home Page Oh What a Tangled Biofilm Web Bacteria Weave By Elia Ben-Ari Posted May 1, ... a suitable surface, some water and nutrients, and bacteria will likely put down stakes and form biofilms. ...

  1. Biofilm Formation As a Response to Ecological Competition

    PubMed Central

    Oliveira, Nuno M.; Martinez-Garcia, Esteban; Xavier, Joao; Durham, William M.; Kolter, Roberto; Kim, Wook; Foster, Kevin R.

    2015-01-01

    Bacteria form dense surface-associated communities known as biofilms that are central to their persistence and how they affect us. Biofilm formation is commonly viewed as a cooperative enterprise, where strains and species work together for a common goal. Here we explore an alternative model: biofilm formation is a response to ecological competition. We co-cultured a diverse collection of natural isolates of the opportunistic pathogen Pseudomonas aeruginosa and studied the effect on biofilm formation. We show that strain mixing reliably increases biofilm formation compared to unmixed conditions. Importantly, strain mixing leads to strong competition: one strain dominates and largely excludes the other from the biofilm. Furthermore, we show that pyocins, narrow-spectrum antibiotics made by other P. aeruginosa strains, can stimulate biofilm formation by increasing the attachment of cells. Side-by-side comparisons using microfluidic assays suggest that the increase in biofilm occurs due to a general response to cellular damage: a comparable biofilm response occurs for pyocins that disrupt membranes as for commercial antibiotics that damage DNA, inhibit protein synthesis or transcription. Our data show that bacteria increase biofilm formation in response to ecological competition that is detected by antibiotic stress. This is inconsistent with the idea that sub-lethal concentrations of antibiotics are cooperative signals that coordinate microbial communities, as is often concluded. Instead, our work is consistent with competition sensing where low-levels of antibiotics are used to detect and respond to the competing genotypes that produce them. PMID:26158271

  2. Biofilm Formation As a Response to Ecological Competition.

    PubMed

    Oliveira, Nuno M; Oliveria, Nuno M; Martinez-Garcia, Esteban; Xavier, Joao; Durham, William M; Kolter, Roberto; Kim, Wook; Foster, Kevin R

    2015-07-01

    Bacteria form dense surface-associated communities known as biofilms that are central to their persistence and how they affect us. Biofilm formation is commonly viewed as a cooperative enterprise, where strains and species work together for a common goal. Here we explore an alternative model: biofilm formation is a response to ecological competition. We co-cultured a diverse collection of natural isolates of the opportunistic pathogen Pseudomonas aeruginosa and studied the effect on biofilm formation. We show that strain mixing reliably increases biofilm formation compared to unmixed conditions. Importantly, strain mixing leads to strong competition: one strain dominates and largely excludes the other from the biofilm. Furthermore, we show that pyocins, narrow-spectrum antibiotics made by other P. aeruginosa strains, can stimulate biofilm formation by increasing the attachment of cells. Side-by-side comparisons using microfluidic assays suggest that the increase in biofilm occurs due to a general response to cellular damage: a comparable biofilm response occurs for pyocins that disrupt membranes as for commercial antibiotics that damage DNA, inhibit protein synthesis or transcription. Our data show that bacteria increase biofilm formation in response to ecological competition that is detected by antibiotic stress. This is inconsistent with the idea that sub-lethal concentrations of antibiotics are cooperative signals that coordinate microbial communities, as is often concluded. Instead, our work is consistent with competition sensing where low-levels of antibiotics are used to detect and respond to the competing genotypes that produce them. PMID:26158271

  3. Mathematical modeling of dormant cell formation in growing biofilm

    PubMed Central

    Chihara, Kotaro; Matsumoto, Shinya; Kagawa, Yuki; Tsuneda, Satoshi

    2015-01-01

    Understanding the dynamics of dormant cells in microbial biofilms, in which the bacteria are embedded in extracellular matrix, is important for developing successful antibiotic therapies against pathogenic bacteria. Although some of the molecular mechanisms leading to bacterial persistence have been speculated in planktonic bacterial cell, how dormant cells emerge in the biofilms of pathogenic bacteria such as Pseudomonas aeruginosa remains unclear. The present study proposes four hypotheses of dormant cell formation; stochastic process, nutrient-dependent, oxygen-dependent, and time-dependent processes. These hypotheses were implemented into a three-dimensional individual-based model of biofilm formation. Numerical simulations of the different mechanisms yielded qualitatively different spatiotemporal distributions of dormant cells in the growing biofilm. Based on these simulation results, we discuss what kinds of experimental studies are effective for discriminating dormant cell formation mechanisms in biofilms. PMID:26074911

  4. Vaginal Lactobacillus: biofilm formation in vivo - clinical implications.

    PubMed

    Ventolini, Gary

    2015-01-01

    Vaginal lactobacilli provide protection against intrusive pathogenic bacteria. Some Lactobacillus spp. produce in vitro a thick, protective biofilm. We report in vivo formation of biofilm by vaginal Lactobacillus jensenii. The biofilm formation was captured in fresh wet-mount microscopic samples from asymptomatic patients after treatment for recurrent bacterial vaginitis. In vivo documentation of biofilm formation is in our opinion noteworthy, and has significant clinical implications, among which are the possibility to isolate, grow, and therapeutically utilize lactobacilli to prevent recurrent vaginal infections and preterm labor associated with vaginal microbial pathogens. PMID:25733930

  5. Vaginal Lactobacillus: biofilm formation in vivo – clinical implications

    PubMed Central

    Ventolini, Gary

    2015-01-01

    Vaginal lactobacilli provide protection against intrusive pathogenic bacteria. Some Lactobacillus spp. produce in vitro a thick, protective biofilm. We report in vivo formation of biofilm by vaginal Lactobacillus jensenii. The biofilm formation was captured in fresh wet-mount microscopic samples from asymptomatic patients after treatment for recurrent bacterial vaginitis. In vivo documentation of biofilm formation is in our opinion noteworthy, and has significant clinical implications, among which are the possibility to isolate, grow, and therapeutically utilize lactobacilli to prevent recurrent vaginal infections and preterm labor associated with vaginal microbial pathogens. PMID:25733930

  6. Cyclic di-AMP mediates biofilm formation.

    PubMed

    Peng, Xian; Zhang, Yang; Bai, Guangchun; Zhou, Xuedong; Wu, Hui

    2016-03-01

    Cyclic di-AMP (c-di-AMP) is an emerging second messenger in bacteria. It has been shown to play important roles in bacterial fitness and virulence. However, transduction of c-di-AMP signaling in bacteria and the role of c-di-AMP in biofilm formation are not well understood. The level of c-di-AMP is modulated by activity of di-adenylyl cyclase that produces c-di-AMP and phosphodiesterase (PDE) that degrades c-di-AMP. In this study, we determined that increased c-di-AMP levels by deletion of the pdeA gene coding for a PDE promoted biofilm formation in Streptococcus mutans. Deletion of pdeA upregulated expression of gtfB, the gene coding for a major glucan producing enzyme. Inactivation of gtfB blocked the increased biofilm by the pdeA mutant. Two c-di-AMP binding proteins including CabPA (SMU_1562) and CabPB (SMU_1708) were identified. Interestingly, only CabPA deficiency inhibited both the increased biofilm formation and the upregulated expression of GtfB observed in the pdeA mutant. In addition, CabPA but not CabPB interacted with VicR, a known transcriptional factor that regulates expression of gtfB, suggesting that a signaling link between CabPA and GtfB through VicR. Increased biofilm by the pdeA deficiency also enhanced bacterial colonization of Drosophila in vivo. Taken together, our studies reveal a new role of c-di-AMP in mediating biofilm formation through a CabPA/VicR/GtfB signaling network in S. mutans. PMID:26564551

  7. Potent Antibacterial Nanoparticles against Biofilm and Intracellular Bacteria

    PubMed Central

    Mu, Haibo; Tang, Jiangjiang; Liu, Qianjin; Sun, Chunli; Wang, Tingting; Duan, Jinyou

    2016-01-01

    The chronic infections related to biofilm and intracellular bacteria are always hard to be cured because of their inherent resistance to both antimicrobial agents and host defenses. Herein we develop a facile approach to overcome the above conundrum through phosphatidylcholine-decorated Au nanoparticles loaded with gentamicin (GPA NPs). The nanoparticles were characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS) and ultraviolet−visible (UV−vis) absorption spectra which demonstrated that GPA NPs with a diameter of approximately 180 nm were uniform. The loading manner and release behaviors were also investigated. The generated GPA NPs maintained their antibiotic activities against planktonic bacteria, but more effective to damage established biofilms and inhibited biofilm formation of pathogens including Gram-positive and Gram-negative bacteria. In addition, GPA NPs were observed to be nontoxic to RAW 264.7 cells and readily engulfed by the macrophages, which facilitated the killing of intracellular bacteria in infected macrophages. These results suggested GPA NPs might be a promising antibacterial agent for effective treatment of chronic infections due to microbial biofilm and intracellular bacteria. PMID:26728712

  8. Potent Antibacterial Nanoparticles against Biofilm and Intracellular Bacteria.

    PubMed

    Mu, Haibo; Tang, Jiangjiang; Liu, Qianjin; Sun, Chunli; Wang, Tingting; Duan, Jinyou

    2016-01-01

    The chronic infections related to biofilm and intracellular bacteria are always hard to be cured because of their inherent resistance to both antimicrobial agents and host defenses. Herein we develop a facile approach to overcome the above conundrum through phosphatidylcholine-decorated Au nanoparticles loaded with gentamicin (GPA NPs). The nanoparticles were characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS) and ultraviolet-visible (UV-vis) absorption spectra which demonstrated that GPA NPs with a diameter of approximately 180 nm were uniform. The loading manner and release behaviors were also investigated. The generated GPA NPs maintained their antibiotic activities against planktonic bacteria, but more effective to damage established biofilms and inhibited biofilm formation of pathogens including Gram-positive and Gram-negative bacteria. In addition, GPA NPs were observed to be nontoxic to RAW 264.7 cells and readily engulfed by the macrophages, which facilitated the killing of intracellular bacteria in infected macrophages. These results suggested GPA NPs might be a promising antibacterial agent for effective treatment of chronic infections due to microbial biofilm and intracellular bacteria. PMID:26728712

  9. Biofilm formation of Pasteurella multocida on bentonite clay

    PubMed Central

    Rajagopal, Ramachandranpillai; Nair, Govindapillai Krishnan; Mini, Mangattumuruppel; Joseph, Leo; Saseendranath, Mapranath Raghavan; John, Koshy

    2013-01-01

    Background and objectives Biofilms are structural communities of bacterial cells enshrined in a self produced polymeric matrix. The studies on biofilm formation of Pasteurella multocida have become imperative since it is a respiratory pathogen and its biofilm mode could possibly be one of its virulence factors for survival inside a host. The present study describes a biofilm assay for P. multocida on inert hydrophilic material called bentonite clay. Materials and methods The potential of the organism to form in vitro biofilm was assessed by growing the organism under nutrient restriction along with the inert substrate bentonite clay, which will provide a surface for attachment. For quantification of biofilm, plate count by the spread plate method was employed. Capsule production of the attached bacteria was demonstrated by light microscopic examination following Maneval staining and capsular polysaccharide estimation was done using standard procedures. Results and Conclusion The biofilm formation peaked on the third day of incubation (1.54 106 cfu/g of bentonite clay) while the planktonic cells were found to be at a maximum on day one post inoculation (8.10 108 cfu/ml of the broth). Maneval staining of late logarithmic phase biofilm cultures revealed large aggregates of bacterial cells, bacteria appearing as chains or as a meshwork. The capsular polysaccharide estimation of biofilm cells revealed a 3.25 times increase over the planktonic bacteria. The biofilm cells cultured on solid media also produced some exclusive colony morphotypes. PMID:23825728

  10. Ginger Extract Inhibits Biofilm Formation by Pseudomonas aeruginosa PA14

    PubMed Central

    Kim, Han-Shin; Park, Hee-Deung

    2013-01-01

    Bacterial biofilm formation can cause serious problems in clinical and industrial settings, which drives the development or screening of biofilm inhibitors. Some biofilm inhibitors have been screened from natural products or modified from natural compounds. Ginger has been used as a medicinal herb to treat infectious diseases for thousands of years, which leads to the hypothesis that it may contain chemicals inhibiting biofilm formation. To test this hypothesis, we evaluated gingers ability to inhibit Pseudomonas aeruginosa PA14 biofilm formation. A static biofilm assay demonstrated that biofilm development was reduced by 3956% when ginger extract was added to the culture. In addition, various phenotypes were altered after ginger addition of PA14. Ginger extract decreased production of extracellular polymeric substances. This finding was confirmed by chemical analysis and confocal laser scanning microscopy. Furthermore, ginger extract formed noticeably less rugose colonies on agar plates containing Congo red and facilitated swarming motility on soft agar plates. The inhibition of biofilm formation and the altered phenotypes appear to be linked to a reduced level of a second messenger, bis-(3?-5?)-cyclic dimeric guanosine monophosphate. Importantly, ginger extract inhibited biofilm formation in both Gram-positive and Gram-negative bacteria. Also, surface biofilm cells formed with ginger extract detached more easily with surfactant than did those without ginger extract. Taken together, these findings provide a foundation for the possible discovery of a broad spectrum biofilm inhibitor. PMID:24086697

  11. Small RNAs and their role in biofilm formation

    PubMed Central

    Chambers, Jacob R.; Sauer, Karin

    2013-01-01

    The formation of biofilms is initiated by bacteria transitioning from the planktonic to the surface associated mode of growth. Several regulatory systems have been described to govern the initiation and subsequent formation of biofilms. Recent evidence suggests that regulatory networks governing the decision of bacteria whether to attach and form biofilms or remain as planktonic cells, are further subject to regulation by small non-coding RNAs (sRNAs). This is accomplished by sRNAs finetuning regulatory networks enabling concentration-specific responses, by sequestering, antagonizing or activating regulatory proteins in response to environmental cues, or by directly affecting the synthesis of proteins promoting/disfavoring the formation of biofilms. This review is aimed at giving an overview of the contribution of sRNAs in regulating the switch from the planktonic to the sessile bacterial lifestyle by highlighting how sRNAs converge with known regulatory systems required for biofilm formation. PMID:23178000

  12. Lethal photosensitization of biofilm-grown bacteria

    NASA Astrophysics Data System (ADS)

    Wilson, Michael

    1997-12-01

    Antibacterial agents are increasingly being used for the prophylaxis and treatment of oral diseases. As these agents can be rendered ineffective by resistance development in the target organisms there is a need to develop alternative antimicrobial approaches. Light-activated antimicrobial agents release singlet oxygen and free radicals which can kill adjacent bacteria and a wide range of cariogenic and periodontopathogenic bacteria has been shown to be susceptible to such agents. In the oral cavity these organisms are present as biofilms (dental plaques) which are less susceptible to traditional antimicrobial agents than bacterial suspensions. The results of these studies have shown that biofilm-grown oral bacteria are also susceptible to lethal photosensitization although the light energy doses required are grater than those needed to kill the organisms when they are grown as aqueous suspensions.

  13. [Streptomycetes Biofilms. I. Occurrence and Formation].

    PubMed

    Vinogradova, K A; Bulgakova, V G; Polin, A N; Kozhevin, P A

    2015-01-01

    Streptomycetes, soil-dwelling mycelial bacteria, can form biofilms as indigenous components of the environment. The biofilms formed by streptomycetes exist in different ecological niches, in natural, medical, industrial environments. The biofilm-forming streptomycetes affect water quality, human health, associate with deterioration of artworks and historical monuments. The review should be of interest for researchers of the biofilm mode of streptomycetes growth. PMID:26168684

  14. Effect of residual sanitizers on Salmonella enterica biofilm formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Salmonella enterica are a diverse group of bacteria that represent a serious risk to public health. Bacterial attachment on food and contact surfaces can lead to biofilm formation, and once in this state, bacteria are more resistant to sanitization and may serve as a continuous contam...

  15. Electron microscopic examination of wastewater biofilm formation and structural components.

    PubMed Central

    Eighmy, T T; Maratea, D; Bishop, P L

    1983-01-01

    This research documents in situ wastewater biofilm formation, structure, and physiochemical properties as revealed by scanning and transmission electron microscopy. Cationized ferritin was used to label anionic sites of the biofilm glycocalyx for viewing in thin section. Wastewater biofilm formation paralleled the processes involved in marine biofilm formation. Scanning electron microscopy revealed a dramatic increase in cell colonization and growth over a 144-h period. Constituents included a variety of actively dividing morphological types. Many of the colonizing bacteria were flagellated. Filaments were seen after primary colonization of the surface. Transmission electron microscopy revealed a dominant gram-negative cell wall structure in the biofilm constituents. At least three types of glycocalyces were observed. The predominant glycocalyx possessed interstices and was densely labeled with cationized ferritin. Two of the glycocalyces appeared to mediate biofilm adhesion to the substratum. The results suggest that the predominant glycocalyx of this thin wastewater biofilm serves, in part, to: (i) enclose the bacteria in a matrix and anchor the biofilm to the substratum and (ii) provide an extensive surface area with polyanionic properties. Images PMID:6881965

  16. Effects of patterned topography on biofilm formation

    NASA Astrophysics Data System (ADS)

    Vasudevan, Ravikumar

    2011-12-01

    Bacterial biofilms are a population of bacteria attached to each other and irreversibly to a surface, enclosed in a matrix of self-secreted polymers, among others polysaccharides, proteins, DNA. Biofilms cause persisting infections associated with implanted medical devices and hospital acquired (nosocomial) infections. Catheter-associated urinary tract infections (CAUTIs) are the most common type of nosocomial infections accounting for up to 40% of all hospital acquired infections. Several different strategies, including use of antibacterial agents and genetic cues, quorum sensing, have been adopted for inhibiting biofilm formation relevant to CAUTI surfaces. Each of these methods pertains to certain types of bacteria, processes and has shortcomings. Based on eukaryotic cell topography interaction studies and Ulva linza spore studies, topographical surfaces were suggested as a benign control method for biofilm formation. However, topographies tested so far have not included a systematic variation of size across basic topography shapes. In this study patterned topography was systematically varied in size and shape according to two approaches 1) confinement and 2) wetting. For the confinement approach, using scanning electron microscopy and confocal microscopy, orienting effects of tested topography based on staphylococcus aureus (s. aureus) (SH1000) and enterobacter cloacae (e. cloacae) (ATCC 700258) bacterial models were identified on features of up to 10 times the size of the bacterium. Psuedomonas aeruginosa (p. aeruginosa) (PAO1) did not show any orientational effects, under the test conditions. Another important factor in medical biofilms is the identification and quantification of phenotypic state which has not been discussed in the literature concerning bacteria topography characterizations. This was done based on antibiotic susceptibility evaluation and also based on gene expression analysis. Although orientational effects occur, phenotypically no difference was observed between the patterned topography tested. Another potential strategy for biofilm control through patterned topography is based on the design of robust non-wetting surfaces with undercut feature geometries, characterized by 1) breakthrough pressure and 2) triple phase contact line model. It was found that height and presence of undercut had statistically significant effects, directly proportional to breakthrough pressures, whereas extent of undercut did not. A predictive triple phase contact line model was also developed. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

  17. Streptococcus pneumoniae biofilm formation and dispersion during colonization and disease

    PubMed Central

    Chao, Yashuan; Marks, Laura R.; Pettigrew, Melinda M.; Hakansson, Anders P.

    2015-01-01

    Streptococcus pneumoniae (the pneumococcus) is a common colonizer of the human nasopharynx. Despite a low rate of invasive disease, the high prevalence of colonization results in millions of infections and over one million deaths per year, mostly in individuals under the age of 5 and the elderly. Colonizing pneumococci form well-organized biofilm communities in the nasopharyngeal environment, but the specific role of biofilms and their interaction with the host during colonization and disease is not yet clear. Pneumococci in biofilms are highly resistant to antimicrobial agents and this phenotype can be recapitulated when pneumococci are grown on respiratory epithelial cells under conditions found in the nasopharyngeal environment. Pneumococcal biofilms display lower levels of virulence in vivo and provide an optimal environment for increased genetic exchange both in vitro and in vivo, with increased natural transformation seen during co-colonization with multiple strains. Biofilms have also been detected on mucosal surfaces during pneumonia and middle ear infection, although the role of these biofilms in the disease process is debated. Recent studies have shown that changes in the nasopharyngeal environment caused by concomitant virus infection, changes in the microflora, inflammation, or other host assaults trigger active release of pneumococci from biofilms. These dispersed bacteria have distinct phenotypic properties and transcriptional profiles different from both biofilm and broth-grown, planktonic bacteria, resulting in a significantly increased virulence in vivo. In this review we discuss the properties of pneumococcal biofilms, the role of biofilm formation during pneumococcal colonization, including their propensity for increased ability to exchange genetic material, as well as mechanisms involved in transition from asymptomatic biofilm colonization to dissemination and disease of otherwise sterile sites. Greater understanding of pneumococcal biofilm formation and dispersion will elucidate novel avenues to interfere with the spread of antibiotic resistance and vaccine escape, as well as novel strategies to target the mechanisms involved in induction of pneumococcal disease. PMID:25629011

  18. Anti-Biofilm Activities from Marine Cold Adapted Bacteria Against Staphylococci and Pseudomonas aeruginosa

    PubMed Central

    Papa, Rosanna; Selan, Laura; Parrilli, Ermenegilda; Tilotta, Marco; Sannino, Filomena; Feller, Georges; Tutino, Maria L.; Artini, Marco

    2015-01-01

    Microbial biofilms have great negative impacts on the world’s economy and pose serious problems to industry, public health and medicine. The interest in the development of new approaches for the prevention and treatment of bacterial adhesion and biofilm formation has increased. Since, bacterial pathogens living in biofilm induce persistent chronic infections due to the resistance to antibiotics and host immune system. A viable approach should target adhesive properties without affecting bacterial vitality in order to avoid the appearance of resistant mutants. Many bacteria secrete anti-biofilm molecules that function in regulating biofilm architecture or mediating the release of cells from it during the dispersal stage of biofilm life cycle. Cold-adapted marine bacteria represent an untapped reservoir of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules. The anti-biofilm activity of cell-free supernatants derived from sessile and planktonic cultures of cold-adapted bacteria belonging to Pseudoalteromonas, Psychrobacter, and Psychromonas species were tested against Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa strains. Reported results demonstrate that we have selected supernatants, from cold-adapted marine bacteria, containing non-biocidal agents able to destabilize biofilm matrix of all tested pathogens without killing cells. A preliminary physico-chemical characterization of supernatants was also performed, and these analyses highlighted the presence of molecules of different nature that act by inhibiting biofilm formation. Some of them are also able to impair the initial attachment of the bacterial cells to the surface, thus likely containing molecules acting as anti-biofilm surfactant molecules. The described ability of cold-adapted bacteria to produce effective anti-biofilm molecules paves the way to further characterization of the most promising molecules and to test their use in combination with conventional antibiotics. PMID:26696962

  19. Anti-Biofilm Activities from Marine Cold Adapted Bacteria Against Staphylococci and Pseudomonas aeruginosa.

    PubMed

    Papa, Rosanna; Selan, Laura; Parrilli, Ermenegilda; Tilotta, Marco; Sannino, Filomena; Feller, Georges; Tutino, Maria L; Artini, Marco

    2015-01-01

    Microbial biofilms have great negative impacts on the world's economy and pose serious problems to industry, public health and medicine. The interest in the development of new approaches for the prevention and treatment of bacterial adhesion and biofilm formation has increased. Since, bacterial pathogens living in biofilm induce persistent chronic infections due to the resistance to antibiotics and host immune system. A viable approach should target adhesive properties without affecting bacterial vitality in order to avoid the appearance of resistant mutants. Many bacteria secrete anti-biofilm molecules that function in regulating biofilm architecture or mediating the release of cells from it during the dispersal stage of biofilm life cycle. Cold-adapted marine bacteria represent an untapped reservoir of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules. The anti-biofilm activity of cell-free supernatants derived from sessile and planktonic cultures of cold-adapted bacteria belonging to Pseudoalteromonas, Psychrobacter, and Psychromonas species were tested against Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa strains. Reported results demonstrate that we have selected supernatants, from cold-adapted marine bacteria, containing non-biocidal agents able to destabilize biofilm matrix of all tested pathogens without killing cells. A preliminary physico-chemical characterization of supernatants was also performed, and these analyses highlighted the presence of molecules of different nature that act by inhibiting biofilm formation. Some of them are also able to impair the initial attachment of the bacterial cells to the surface, thus likely containing molecules acting as anti-biofilm surfactant molecules. The described ability of cold-adapted bacteria to produce effective anti-biofilm molecules paves the way to further characterization of the most promising molecules and to test their use in combination with conventional antibiotics. PMID:26696962

  20. Shewanella putrefaciens Adhesion and Biofilm Formation on Food Processing Surfaces

    PubMed Central

    Bagge, Dorthe; Hjelm, Mette; Johansen, Charlotte; Huber, Ingrid; Gram, Lone

    2001-01-01

    Laboratory model systems were developed for studying Shewanella putrefaciens adhesion and biofilm formation under batch and flow conditions. S. putrefaciens plays a major role in food spoilage and may cause microbially induced corrosion on steel surfaces. S. putrefaciens bacteria suspended in buffer adhered readily to stainless steel surfaces. Maximum numbers of adherent bacteria per square centimeter were reached in 8 h at 25°C and reflected the cell density in suspension. Numbers of adhering bacteria from a suspension containing 108 CFU/ml were much lower in a laminar flow system (modified Robbins device) (reaching 102 CFU/cm2) than in a batch system (reaching 107 CFU/cm2), and maximum numbers were reached after 24 h. When nutrients were supplied, S. putrefaciens grew in biofilms with layers of bacteria. The rate of biofilm formation and the thickness of the film were not dependent on the availability of carbohydrate (lactate or glucose) or on iron starvation. The number of S. putrefaciens bacteria on the surface was partly influenced by the presence of other bacteria (Pseudomonas fluorescens) which reduced the numbers of S. putrefaciens bacteria in the biofilm. Numbers of bacteria on the surface must be quantified to evaluate the influence of environmental factors on adhesion and biofilm formation. We used a combination of fluorescence microscopy (4′,6′-diamidino-2-phenylindole staining and in situ hybridization, for mixed-culture studies), ultrasonic removal of bacteria from surfaces, and indirect conductometry and found this combination sufficient to quantify bacteria on surfaces. PMID:11319118

  1. Printed paper-based arrays as substrates for biofilm formation

    PubMed Central

    2014-01-01

    The suitability of paper-based arrays for biofilm formation studies by Staphylococcus aureus is demonstrated. Laboratory-coated papers with different physicochemical properties were used as substrates. The array platform was fabricated by patterning the coated papers with vinyl-substituted polydimethylsiloxane (PDMS) -based ink. The affinity of bacteria onto the flexographically printed hydrophobic and smooth PDMS film was very low whereas bacterial adhesion and biofilm formation occurred preferentially on the unprinted areas, i.e. in the reaction arrays. The concentration of the attached bacteria was quantified by determining the viable colony forming unit (CFU/cm2) numbers. The distribution and the extent of surface coverage of the biofilms were determined by atomic force microscopy. In static conditions, the highest bacterial concentration and most highly organized biofilms were observed on substrates with high polarity. On a rough paper surface with low polarity, the biofilm formation was most hindered. Biofilms were effectively removed from a polar substrate upon exposure to (+)-dehydroabietic acid, an anti-biofilm compound. PMID:25006538

  2. Boundaries for Biofilm Formation: Humidity and Temperature

    PubMed Central

    Else, Terry Ann; Pantle, Curtis R.; Amy, Penny S.

    2003-01-01

    Environmental conditions which define boundaries for biofilm production could provide useful ecological information for biofilm models. A practical use of defined conditions could be applied to the high-level nuclear waste repository at Yucca Mountain. Data for temperature and humidity conditions indicate that decreases in relative humidity or increased temperature severely affect biofilm formation on three candidate canister metals. PMID:12902302

  3. Boundaries for biofilm formation: humidity and temperature.

    PubMed

    Else, Terry Ann; Pantle, Curtis R; Amy, Penny S

    2003-08-01

    Environmental conditions which define boundaries for biofilm production could provide useful ecological information for biofilm models. A practical use of defined conditions could be applied to the high-level nuclear waste repository at Yucca Mountain. Data for temperature and humidity conditions indicate that decreases in relative humidity or increased temperature severely affect biofilm formation on three candidate canister metals. PMID:12902302

  4. Association Between Toxin-Antitoxin Systems and Biofilm Formation

    PubMed Central

    Karimi, Sajedeh; Ghafourian, Sobhan; Taheri Kalani, Morovat; Azizi Jalilian, Farid; Hemati, Saeed; Sadeghifard, Nourkhoda

    2014-01-01

    Background: Toxin-antitoxin (TA) systems are found on the chromosomes and plasmids of many Bacteria such as Escherichia coli. The roles of TA systems in bacteria are enigmatic. Multiple biological functions of TA systems are proposed including growth modulation, persistence, and biofilm formation. Biofilms of E. coli are cause of urinary tract infections, as well as bacteraemia. Objectives: The current study aimed to find the association between biofilm formation and toxin-antitoxin systems in clinical isolates of E. coli. Materials and Methods: A total of 150 E. coli isolates were evaluated for biofilm formation by Congo red agar medium (CRA) and microtiter plate assay and the presence of different TA systems including MazEF, RelBE, hipBA, ccdAB and MqsRA. Results: The results of the analysis revealed that 107 E. coli isolates were potent for biofilm formation by CRA. The findings by microtiter plates showed that 102 E. coli isolates were biofilm producers. The results indicated that 80%, 85%, 70%, 91% and 82% of the isolates possessed MazEF, RelBE, hipBA, ccdAB and MqsRA TA loci, respectively. Conclusions: The analysis recommended that TA genes are prevalent in clinical isolates of E. coli strains. The analysis revealed that hipBA TA system is associated with biofilm formation. PMID:25789127

  5. Analysis of biofilm formation by intestinal lactobacilli.

    PubMed

    Slížová, Magdaléna; Nemcová, Radomíra; Mad'ar, Marián; Hadryová, Jana; Gancarčíková, Soňa; Popper, Miroslav; Pistl, Juraj

    2015-06-01

    In this study, the biofilm-forming potential of intestinal Lactobacillus reuteri strains under different culture conditions was characterized by microtiter plate biofilm assays. Moreover, the spatial organization of exogenously applied L. reuteri L2/6 (a pig isolate) at specific locations in gastrointestinal tract of monoassociated mice was investigated by fluorescence in situ hybridization. We did not detect biofilm formation by tested strains in nutrient-rich de Man-Rogosa-Sharpe (MRS) medium. On the contrary, a highly positive biofilm formation was observed in medium with lower accessibility to the carbon sources and lack of salts. The results obtained confirmed the significant role of Tween 80 and the quantity and nature of the sugars in the growth medium in biofilm formation. The omission of Tween 80 in MRS medium favored the formation of biofilm. Abundant biofilm formation was detected in the presence of lactose, galactose, and glucose. However, a gradual increase in sugar concentration triggered a significant decrease in biofilm formation. In addition, conditions related to the gastrointestinal environment, such as low pH and the presence of bile and mucins, highly modulated biofilm production. This effect seems to be dependent on the specificity and properties of the medium used for cultivation. From the evidence provided by this study we conclude that the biofilm formation capacity of L. reuteri is strongly dependent on the environmental factors and culture medium used. PMID:25961850

  6. Identification of Listeria monocytogenes determinants required for biofilm formation.

    PubMed

    Alonso, Almaris N; Perry, Kyle J; Regeimbal, James M; Regan, Patrick M; Higgins, Darren E

    2014-01-01

    Listeria monocytogenes is a Gram-positive, food-borne pathogen of humans and animals. L. monocytogenes is considered to be a potential public health risk by the U.S. Food and Drug Administration (FDA), as this bacterium can easily contaminate ready-to-eat (RTE) foods and cause an invasive, life-threatening disease (listeriosis). Bacteria can adhere and grow on multiple surfaces and persist within biofilms in food processing plants, providing resistance to sanitizers and other antimicrobial agents. While whole genome sequencing has led to the identification of biofilm synthesis gene clusters in many bacterial species, bioinformatics has not identified the biofilm synthesis genes within the L. monocytogenes genome. To identify genes necessary for L. monocytogenes biofilm formation, we performed a transposon mutagenesis library screen using a recently constructed Himar1 mariner transposon. Approximately 10,000 transposon mutants within L. monocytogenes strain 10403S were screened for biofilm formation in 96-well polyvinyl chloride (PVC) microtiter plates with 70 Himar1 insertion mutants identified that produced significantly less biofilms. DNA sequencing of the transposon insertion sites within the isolated mutants revealed transposon insertions within 38 distinct genetic loci. The identification of mutants bearing insertions within several flagellar motility genes previously known to be required for the initial stages of biofilm formation validated the ability of the mutagenesis screen to identify L. monocytogenes biofilm-defective mutants. Two newly identified genetic loci, dltABCD and phoPR, were selected for deletion analysis and both ?dltABCD and ?phoPR bacterial strains displayed biofilm formation defects in the PVC microtiter plate assay, confirming these loci contribute to biofilm formation by L. monocytogenes. PMID:25517120

  7. Identification of Listeria monocytogenes Determinants Required for Biofilm Formation

    PubMed Central

    Regeimbal, James M.; Regan, Patrick M.; Higgins, Darren E.

    2014-01-01

    Listeria monocytogenes is a Gram-positive, food-borne pathogen of humans and animals. L. monocytogenes is considered to be a potential public health risk by the U.S. Food and Drug Administration (FDA), as this bacterium can easily contaminate ready-to-eat (RTE) foods and cause an invasive, life-threatening disease (listeriosis). Bacteria can adhere and grow on multiple surfaces and persist within biofilms in food processing plants, providing resistance to sanitizers and other antimicrobial agents. While whole genome sequencing has led to the identification of biofilm synthesis gene clusters in many bacterial species, bioinformatics has not identified the biofilm synthesis genes within the L. monocytogenes genome. To identify genes necessary for L. monocytogenes biofilm formation, we performed a transposon mutagenesis library screen using a recently constructed Himar1 mariner transposon. Approximately 10,000 transposon mutants within L. monocytogenes strain 10403S were screened for biofilm formation in 96-well polyvinyl chloride (PVC) microtiter plates with 70 Himar1 insertion mutants identified that produced significantly less biofilms. DNA sequencing of the transposon insertion sites within the isolated mutants revealed transposon insertions within 38 distinct genetic loci. The identification of mutants bearing insertions within several flagellar motility genes previously known to be required for the initial stages of biofilm formation validated the ability of the mutagenesis screen to identify L. monocytogenes biofilm-defective mutants. Two newly identified genetic loci, dltABCD and phoPR, were selected for deletion analysis and both ΔdltABCD and ΔphoPR bacterial strains displayed biofilm formation defects in the PVC microtiter plate assay, confirming these loci contribute to biofilm formation by L. monocytogenes. PMID:25517120

  8. Ecology of Anti-Biofilm Agents II: Bacteriophage Exploitation and Biocontrol of Biofilm Bacteria

    PubMed Central

    Abedon, Stephen T.

    2015-01-01

    Bacteriophages are the viruses of bacteria. In the guise of phage therapy they have been used for decades to successfully treat what are probable biofilm-containing chronic bacterial infections. More recently, phage treatment or biocontrol of biofilm bacteria has been brought back to the laboratory for more rigorous assessment as well as towards the use of phages to combat environmental biofilms, ones other than those directly associated with bacterial infections. Considered in a companion article is the inherent ecological utility of bacteriophages versus antibiotics as anti-biofilm agents. Discussed here is a model for phage ecological interaction with bacteria as they may occur across biofilm-containing ecosystems. Specifically, to the extent that individual bacterial types are not highly abundant within biofilm-containing environments, then phage exploitation of those bacteria may represent a “Feast-or-famine” existence in which infection of highly localized concentrations of phage-sensitive bacteria alternate with treacherous searches by the resulting phage progeny virions for new concentrations of phage-sensitive bacteria to infect. An updated synopsis of the literature concerning laboratory testing of phage use to combat bacterial biofilms is then provided along with tips on how “Ecologically” such phage-mediated biofilm control can be modified to more reliably achieve anti-biofilm efficacy. PMID:26371011

  9. Biofilm formation by Borrelia burgdorferi sensu lato.

    PubMed

    Timmaraju, Venkata Arun; Theophilus, Priyanka A S; Balasubramanian, Kunthavai; Shakih, Shafiq; Luecke, David F; Sapi, Eva

    2015-08-01

    Bacterial biofilms are microbial communities held together by an extracellular polymeric substance matrix predominantly composed of polysaccharides, proteins and nucleic acids. We had previously shown that Borrelia burgdorferi sensu stricto, the causative organism of Lyme disease in the United States is capable of forming biofilms in vitro. Here, we investigated biofilm formation by B. afzelii and B. garinii, which cause Lyme disease in Europe. Using various histochemistry and microscopy techniques, we show that B. afzelii and B. garinii form biofilms, which resemble biofilms formed by B. burgdorferi sensu stricto. High-resolution atomic force microscopy revealed similarities in the ultrastructural organization of the biofilms form by three Borrelia species. Histochemical experiments revealed a heterogeneous organization of exopolysaccharides among the three Borrelia species. These results suggest that biofilm formation might be a common trait of Borrelia genera physiology. PMID:26208529

  10. Identification of a Novel Benzimidazole That Inhibits Bacterial Biofilm Formation in a Broad-Spectrum Manner?

    PubMed Central

    Sambanthamoorthy, Karthik; Gokhale, Ankush A.; Lao, Weiwei; Parashar, Vijay; Neiditch, Matthew B.; Semmelhack, Martin F.; Lee, Ilsoon; Waters, Christopher M.

    2011-01-01

    Bacterial biofilm formation causes significant industrial economic loss and high morbidity and mortality in medical settings. Biofilms are defined as multicellular communities of bacteria encased in a matrix of protective extracellular polymers. Because biofilms have a high tolerance for treatment with antimicrobials, protect bacteria from immune defense, and resist clearance with standard sanitation protocols, it is critical to develop new approaches to prevent biofilm formation. Here, a novel benzimidazole molecule, named antibiofilm compound 1 (ABC-1), identified in a small-molecule screen, was found to prevent bacterial biofilm formation in multiple Gram-negative and Gram-positive bacterial pathogens, including Pseudomonas aeruginosa and Staphylococcus aureus, on a variety of different surface types. Importantly, ABC-1 itself does not inhibit the growth of bacteria, and it is effective at nanomolar concentrations. Also, coating a polystyrene surface with ABC-1 reduces biofilm formation. These data suggest ABC-1 is a new chemical scaffold for the development of antibiofilm compounds. PMID:21709104

  11. Wild Mushroom Extracts as Inhibitors of Bacterial Biofilm Formation

    PubMed Central

    Alves, Maria José; Ferreira, Isabel C. F. R.; Lourenço, Inês; Costa, Eduardo; Martins, Anabela; Pintado, Manuela

    2014-01-01

    Microorganisms can colonize a wide variety of medical devices, putting patients in risk for local and systemic infectious complications, including local-site infections, catheter-related bloodstream infections, and endocarditis. These microorganisms are able to grow adhered to almost every surface, forming architecturally complex communities termed biofilms. The use of natural products has been extremely successful in the discovery of new medicine, and mushrooms could be a source of natural antimicrobials. The present study reports the capacity of wild mushroom extracts to inhibit in vitro biofilm formation by multi-resistant bacteria. Four Gram-negative bacteria biofilm producers (Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and Acinetobacter baumannii) isolated from urine were used to verify the activity of Russula delica, Fistulina hepatica, Mycena rosea, Leucopaxilus giganteus, and Lepista nuda extracts. The results obtained showed that all tested mushroom extracts presented some extent of inhibition of biofilm production. Pseudomonas aeruginosa was the microorganism with the highest capacity of biofilm production, being also the most susceptible to the extracts inhibition capacity (equal or higher than 50%). Among the five tested extracts against E. coli, Leucopaxillus giganteus (47.8%) and Mycenas rosea (44.8%) presented the highest inhibition of biofilm formation. The extracts exhibiting the highest inhibitory effect upon P. mirabilis biofilm formation were Sarcodon imbricatus (45.4%) and Russula delica (53.1%). Acinetobacter baumannii was the microorganism with the lowest susceptibility to mushroom extracts inhibitory effect on biofilm production (highest inhibition—almost 29%, by Russula delica extract). This is a pioneer study since, as far as we know, there are no reports on the inhibition of biofilm production by the studied mushroom extracts and in particular against multi-resistant clinical isolates; nevertheless, other studies are required to elucidate the mechanism of action. PMID:25438017

  12. Cigarette Smoke Increases Staphylococcus aureus Biofilm Formation via Oxidative Stress

    PubMed Central

    Kulkarni, Ritwij; Antala, Swati; Wang, Alice; Amaral, Fábio E.; Rampersaud, Ryan; LaRussa, Samuel J.; Planet, Paul J.

    2012-01-01

    The strong epidemiological association between cigarette smoke (CS) exposure and respiratory tract infections is conventionally attributed to immunosuppressive and irritant effects of CS on human cells. Since pathogenic bacteria such as Staphylococcus aureus are members of the normal microbiota and reside in close proximity to human nasopharyngeal cells, we hypothesized that bioactive components of CS might affect these organisms and potentiate their virulence. Using Staphylococcus aureus as a model organism, we observed that the presence of CS increased both biofilm formation and host cell adherence. Analysis of putative molecular pathways revealed that CS exposure decreased expression of the quorum-sensing agr system, which is involved in biofilm dispersal, and increased transcription of biofilm inducers such as sarA and rbf. CS contains bioactive compounds, including free radicals and reactive oxygen species, and we observed transcriptional induction of bacterial oxidoreductases, including superoxide dismutase, following exposure. Moreover, pretreatment of CS with an antioxidant abrogated CS-mediated enhancement of biofilms. Exposure of bacteria to hydrogen peroxide alone increased biofilm formation. These observations are consistent with the hypothesis that CS induces staphylococcal biofilm formation in an oxidant-dependent manner. CS treatment induced transcription of fnbA (encoding fibronectin binding protein A), leading to increased binding of CS-treated staphylococci to immobilized fibronectin and increased adherence to human cells. These observations indicate that the bioactive effects of CS may extend to the resident microbiota of the nasopharynx, with implications for the pathogenesis of respiratory infection in CS-exposed humans. PMID:22890993

  13. COAGGREGATION OCCURS AMONGST BACTERIA WITHIN AND BETWEEN DOMESTIC SHOWERHEAD BIOFILMS

    PubMed Central

    Vornhagen, Jay; Stevens, Michael; McCormick, David; Dowd, Scot E.; Eisenberg, Joseph N.S.; Boles, Blaise R.; Rickard, Alexander H.

    2014-01-01

    Showerheads support the development multi-species biofilms that can be unsightly, produce malodor, and may harbor pathogens. The outer surface spray plates of many showerheads support visible biofilms that likely contain a mixture of bacteria from freshwater and potentially from human users. Coaggregation, a mechanism by which genetically distinct bacteria specifically recognize one another, may contribute to the retention and enrichment of different species within these biofilms. The aim of this work was to identify the bacterial composition of outer spray plate biofilms of three domestic shower heads and to determine the inter- and intra-biofilm coaggregation ability of each culturable isolate. The bacterial composition of the three biofilms was determined by using bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP) and by culturing on R2A medium. An average of 31 genera per biofilm were identified using bTEFAP and a total of 30 isolates were cultured. Even though the microbial diversity of each showerhead biofilm differed, every cultured isolate was able to coaggregate with at least one other isolate from the same or different showerhead biofilm. Promiscuous coaggregating isolates belonged to the genera Brevundimonas, Micrococcus, and Lysobacter. This work suggests that coaggregation may be a common feature of showerhead biofilms. Characterization of the mechanisms mediating coaggregation, and the inter-species interactions they facilitate, may allow for novel strategies to inhibit biofilm development. PMID:23194413

  14. Agents that inhibit bacterial biofilm formation.

    PubMed

    Rabin, Nira; Zheng, Yue; Opoku-Temeng, Clement; Du, Yixuan; Bonsu, Eric; Sintim, Herman O

    2015-01-01

    In the biofilm form, bacteria are more resistant to various antimicrobial treatments. Bacteria in a biofilm can also survive harsh conditions and withstand the host's immune system. Therefore, there is a need for new treatment options to treat biofilm-associated infections. Currently, research is focused on the development of antibiofilm agents that are nontoxic, as it is believed that such molecules will not lead to future drug resistance. In this review, we discuss recent discoveries of antibiofilm agents and different approaches to inhibit/disperse biofilms. These new antibiofilm agents, which contain moieties such as imidazole, phenols, indole, triazole, sulfide, furanone, bromopyrrole, peptides, etc. have the potential to disperse bacterial biofilms in vivo and could positively impact human medicine in the future. PMID:25921403

  15. Biofilm formation and cellulose expression among diverse environmental Pseudomonas isolates.

    PubMed

    Ude, Susanne; Arnold, Dawn L; Moon, Christina D; Timms-Wilson, Tracey; Spiers, Andrew J

    2006-11-01

    The ability to form biofilms is seen as an increasingly important colonization strategy among both pathogenic and environmental bacteria. A survey of 185 plant-associated, phytopathogenic, soil and river Pseudomonas isolates resulted in 76% producing biofilms at the air-liquid (A-L) interface after selection in static microcosms. Considerable variation in biofilm phenotype was observed, including waxy aggregations, viscous and floccular masses, and physically cohesive biofilms with continuously varying strengths over 1500-fold. Calcofluor epifluorescent microscopy identified cellulose as the matrix component in biofilms produced by Pseudomonas asplenii, Pseudomonas corrugata, Pseudomonas fluorescens, Pseudomonas marginalis, Pseudomonas putida, Pseudomonas savastanoi and Pseudomonas syringae isolates. Cellulose expression and biofilm formation could be induced by the constitutively active WspR19 mutant of the cyclic-di-GMP-associated, GGDEF domain-containing response regulator involved in the P. fluorescens SBW25 wrinkly spreader phenotype and cellular aggregation in Pseudomonas aeruginosa PA01. WspR19 could also induce P. putida KT2440, which otherwise did not produce a biofilm or express cellulose, as well as Escherichia coli K12 and Salmonella typhimurium LT2, both of which express cellulose yet lack WspR homologues. Statistical analysis of biofilm parameters suggest that biofilm development is a more complex process than that simply described by the production of attachment and matrix components and bacterial growth. This complexity was also seen in multivariate analysis as a species-ecological habitat effect, underscoring the fact that in vitro biofilms are abstractions of those surface and volume colonization processes used by bacteria in their natural environments. PMID:17014498

  16. From environmental signals to regulators: modulation of biofilm development in Gram-positive bacteria.

    PubMed

    Mhatre, Eisha; Monterrosa, Ramses Gallegos; Kovács, Akos T

    2014-07-01

    Bacterial lifestyle is influenced by environmental signals, and many differentiation processes in bacteria are governed by the threshold concentrations of molecules present in their niche. Biofilm is one such example where bacteria in their sessile state adapt to a lifestyle that causes several adaptive alterations in the population. Here, a brief overview is given on a variety of environmental signals that bias biofilm development in Gram-positive bacteria, including nutrient conditions, self- and heterologously produced substances, like quorum sensing and host produced molecules. The Gram-positive model organism, Bacillus subtilis is a superb example to illustrate how distinct signals activate sensor proteins that integrate the environmental signals towards global regulators related to biofilm formation. The role of reduced oxygen level, polyketides, antimicrobials, plant secreted carbohydrates, plant cell derived polymers, glycerol, and osmotic conditions are discussed during the transcriptional activation of biofilm related genes in B. subtilis. PMID:24771632

  17. Oh What a Tangled Biofilm Web Bacteria Weave

    MedlinePLUS

    ... a Tangled Biofilm Web Bacteria Weave Inside Life Science View All Articles | Inside Life Science Home Page Oh What a Tangled Biofilm Web ... Conversations Learning from Bacterial Chatter This Inside Life Science article also appears on LiveScience . Learn about related ...

  18. Aspartate inhibits Staphylococcus aureus biofilm formation.

    PubMed

    Yang, Hang; Wang, Mengyue; Yu, Junping; Wei, Hongping

    2015-04-01

    Biofilm formation renders Staphylococcus aureus highly resistant to conventional antibiotics and host defenses. Four D-amino acids (D-Leu, D-Met, D-Trp and D-Tyr) have been reported to be able to inhibit biofilm formation and disassemble established S. aureus biofilms. We report here for the first time that both D- and L-isoforms of aspartate (Asp) inhibited S. aureus biofilm formation on tissue culture plates. Similar biofilm inhibition effects were also observed against other staphylococcal strains, including S. saprophyticus, S. equorum, S. chromogenes and S. haemolyticus. It was found that Asp at high concentrations (>10 mM) inhibited the growth of planktonic N315 cells, but at subinhibitory concentrations decreased the cellular metabolic activity without influencing cell growth. The decreased cellular metabolic activity might be the reason for the production of less protein and DNA in the matrix of the biofilms formed in the presence of Asp. However, varied inhibition efficacies of Asp were observed for biofilms formed by clinical staphylococcal isolates. There might be mechanisms other than decreasing the metabolic activity, e.g. the biofilm phenotypes, affecting biofilm formation in the presence of Asp. PMID:25687923

  19. Candida species: new insights into biofilm formation.

    PubMed

    Cuéllar-Cruz, Mayra; López-Romero, Everardo; Villagómez-Castro, Julio C; Ruiz-Baca, Estela

    2012-06-01

    Biofilms of Candida albicans, Candida parapsilosis, Candida glabrata and Candida tropicalis are associated with high indices of hospital morbidity and mortality. Major factors involved in the formation and growth of Candida biofilms are the chemical composition of the medical implant and the cell wall adhesins responsible for mediating Candida-Candida, Candida-human host cell and Candida-medical device adhesion. Strategies for elucidating the mechanisms that regulate the formation of Candida biofilms combine tools from biology, chemistry, nanoscience, material science and physics. This review proposes the use of new technologies, such as synchrotron radiation, to study the mechanisms of biofilm formation. In the future, this information is expected to facilitate the design of new materials and antifungal compounds that can eradicate nosocomial Candida infections due to biofilm formation on medical implants. This will reduce dissemination of candidiasis and hopefully improve the quality of life of patients. PMID:22702528

  20. Nanoscale Plasma Coating Inhibits Formation of Staphylococcus aureus Biofilm.

    PubMed

    Xu, Yuanxi; Jones, John E; Yu, Haiqing; Yu, Qingsong; Christensen, Gordon D; Chen, Meng; Sun, Hongmin

    2015-12-01

    Staphylococcus aureus commonly infects medical implants or devices, with devastating consequences for the patient. The infection begins with bacterial attachment to the device, followed by bacterial multiplication over the surface of the device, generating an adherent sheet of bacteria known as a biofilm. Biofilms resist antimicrobial therapy and promote persistent infection, making management difficult to futile. Infections might be prevented by engineering the surface of the device to discourage bacterial attachment and multiplication; however, progress in this area has been limited. We have developed a novel nanoscale plasma coating technology to inhibit the formation of Staphylococcus aureus biofilms. We used monomeric trimethylsilane (TMS) and oxygen to coat the surfaces of silicone rubber, a material often used in the fabrication of implantable medical devices. By quantitative and qualitative analysis, the TMS/O2 coating significantly decreased the in vitro formation of S. aureus biofilms; it also significantly decreased in vivo biofilm formation in a mouse model of foreign-body infection. Further analysis demonstrated TMS/O2 coating significantly changed the protein adsorption, which could lead to reduced bacterial adhesion and biofilm formation. These results suggest that TMS/O2 coating can be used to effectively prevent medical implant-related infections. PMID:26369955

  1. Role of Capsular Polysaccharides in Biofilm Formation: An AFM Nanomechanics Study.

    PubMed

    Wang, Huabin; Wilksch, Jonathan J; Strugnell, Richard A; Gee, Michelle L

    2015-06-17

    Bacteria form biofilms to facilitate colonization of biotic and abiotic surfaces, and biofilm formation on indwelling medical devices is a common cause of hospital-acquired infection. Although it is well-recognized that the exopolysaccharide capsule is one of the key bacterial components for biofilm formation, the underlying biophysical mechanism is poorly understood. In the present study, nanomechanical measurements of wild type and specific mutants of the pathogen, Klebsiella pneumoniae, were performed in situ using atomic force microscopy (AFM). Theoretical modeling of the mechanical data and static microtiter plate biofilm assays show that the organization of the capsule can influence bacterial adhesion, and thereby biofilm formation. The capsular organization is affected by the presence of type 3 fimbriae. Understanding the biophysical mechanisms for the impact of the structural organization of the bacterial polysaccharide capsule on biofilm formation will aid the development of strategies to prevent biofilm formation. PMID:26034816

  2. Desiccation tolerance of iron bacteria biofilms on Mars regolith simulants

    NASA Astrophysics Data System (ADS)

    Feyh, Nina; Szewzyk, Ulrich

    2010-05-01

    Iron oxidizing bacteria play an important role in the geological redox cycling of iron on earth. The redox change between Fe(II) and Fe(III) can be used for biological energy production [1]. Therefore iron oxidation in the iron rich martian soils may be or may have been microbially mediated. The microbial conversion of iron is considered to be an ancient form of metabolism [2], so it might have evolved on Mars as well. However, to exist in recent martian soils, bacteria must be able to endure dry and cold conditions. Neutrophilic iron oxidizers can be found in various iron rich aquatic environments, where they lead to the precipitation of insoluble ferric hydroxides. Some of these environments fall temporarily dry, what could have led to an adaptation to desiccation by bacteria, existing there. One strategy of iron bacteria to endure drought stress might be the formation of biofilms by excreting Extracellular Polymeric Substances (EPS). The deposition of iron hydroxides could enable them to endure dry conditions as well. For our experiments, neutrophilic iron oxidizing bacteria have been isolated from a creek in Bad Salzhausen/Hesse and temporarily drying out pools in Tierra del Fuego. Strains from aquatic environments in the national park "Unteres Odertal" and from water wells in Berlin/Brandenburg are included in the tests as well. In desiccation experiments, the capability of iron bacteria to tolerate dry conditions are investigated. The aim of our first experiment is the adaptation to dry conditions. Biofilms of 15 strains are grown on ceramic beads in liquid medium containing complexed Fe(II), established biofilms contain Fe(III) precipitates. The cultures are desiccated in a sterile airflow until the weight of the cultures remained constant. After a desiccation period of 9 h up to 7 d, the beads are transferred to fresh liquid medium. Adapted strains are used in further desiccation experiments, where biofilms are grown on two martian regolith simulants. These mineral mixtures were developed and produced by the Naturkundemuseum Berlin according to recent data of Mars research missions [3, 4, 5, 6, 7]. The minerals are attached to object slides with potassium silicate and biofilms are grown on the mineral surface. The biofilms are quantified by cell counting and the structure is evaluated by epifluorescence microscopy. After desiccation in a sterile airflow, the survival of cells is determined by fluorescence staining. Acknowledgements This research was supported by the Helmholtz Association through the research alliance "Planetary Evolution and Life". References [1] Weber, K. A. et al. (2006). Microorganisms pumping iron: anaerobic microbial iron oxidation and reduction. Nature Reviews Microbiology 4: 752-764. [2] Vargas, M. et al. (1998). Microbiological evidence for Fe(III) reduction on early Earth. Nature 395: 65-67. [3] Bibring, J.-P., Y. Langevin, et al. (2005). Mars surface diversity as revealed by the OMEGA/Mars express observations. Science 307(5715): 1576-1581. [4] Bibring, J.-P., S. W. Squyres, et al. (2006). Merging Views on Mars. Science 313(5795): 1899-1901. [5] Chevrier, V. and P. E. Math (2007). Mineralogy and evolution of the surface of Mars: A review. Planetary and Space Science 55(3): 289-314. [6] McCollom, T. M. and B. M. Hynek (2005). A volcanic environment for bedrock diagenesis at Meridiani Planum on Mars. Nature 438(7071): 1129-1131. [7] Poulet, F., J. P. Bibring, et al. (2005). Phyllosilicates on Mars and implications for early martian climate. Nature 438(7068): 623-627.

  3. In vitro model of bacterial biofilm formation on polyvinyl chloride biomaterial.

    PubMed

    Zhao, Guang-qiang; Ye, Lian-hua; Huang, Yun-chao; Yang, Da-kuan; Li, Li; Xu, Geng; Lei, Yu-jie

    2011-11-01

    The aim of the study was to establish an in vitro model of Staphylococcus epidermidis biofilms on polyvinyl chloride (PVC) material, and to investigate bacterial biofilm formation and its structure using the combined approach of confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM). Staphylococcus epidermidis bacteria (stain RP62A) were incubated with PVC pieces in Tris buffered saline to form biofilms. Biofilm formation was examined at 6, 12, 18, 24, 30, and 48 h. Thicknesses of these biofilms and the number, and percentage of viable cells in biofilms were measured. CT scan images of biofilms were obtained using CLSM and environmental SEM. The results of this study showed that Staphylococcus epidermidis biofilm is a highly organized multi-cellular structure. The biofilm is constituted of large number of viable and dead bacterial cells. Bacterial biofilm formation on the surface of PVC material was found to be a dynamic process with maximal thickness being attained at 12-18 h. These biofilms became mature by 24 h. There was significant difference in the percentage of viable cells along with interior, middle, and outer layers of biofilms (P < 0.05). Staphylococcus epidermidis biofilm is sophisticated in structure and the combination method involving CLSM and SEM was ideal for investigation of biofilms on PVC material. PMID:21735132

  4. Biofilm Formation in Microscopic Double Emulsion Droplets

    NASA Astrophysics Data System (ADS)

    Chang, Connie; Weitz, David

    2012-02-01

    In natural, medical, and industrial settings, there exist surface-associated communities of bacteria known as biofilms. These highly structured films are composed of bacterial cells embedded within self-produced extracellular matrix, usually composed of exopolysaccharides, proteins, and nucleic acids; this matrix serves to protect the bacterial community from antibiotics and environmental stressors. Here, we form biofilms encapsulated within monodisperse, microscopically-sized double emulsion droplets using microfluidics. The bacteria self-organize at the inner liquid-liquid droplet interfaces, multiply, and differentiate into extracellular matrix-producing cells, forming manifold three-dimensional shell-within-a-shell structures of biofilms, templated upon the inner core of spherical liquid droplets. By using microfluidics to encapsulate bacterial cells, we have the ability to view individual cells multiplying in microscopically-sized droplets, which allows for high-throughput analysis in studying the genetic program leading to biofilm development, or cell signaling that induces differentiation.

  5. Biofilm Formation Derived from Ambient Air and the Characteristics of Apparatus

    NASA Astrophysics Data System (ADS)

    Kanematsu, H.; Kougo, H.; Kuroda, D.; Itho, H.; Ogino, Y.; Yamamoto, Y.

    2013-04-01

    Biofilm is a kind of thin film on solidified matters, being derived from bacteria. Generally, planktonic bacteria float in aqueous environments, soil or air, most of which can be regarded as oligotrophic environments. Since they have to survive by instinct, they seek for nutrients that would exist on materials surfaces as organic matters. Therefore, bacteria attach materials surfaces reversibly. The attachment and detachment repeat for a while and finally, they attach on them irreversibly and the number of bacteria on them increases. At a threshold number, bacteria produce polymeric matters at the same time by quorum sensing mechanism and the biofilm produces on material surfaces. The biofilm produced in that way generally contains water (more than 80%), EPS (Exopolymeric Substance) and bacteria themselves. And they might bring about many industrial problems, fouling, corrosion etc. Therefore, it is very important for us to control and prevent the biofilm formation properly. However, it is generally very hard to produce biofilm experimentally and constantly in ambient atmosphere on labo scale. The authors invented an apparatus where biofilm could form on specimen's surfaces from house germs in the ambient air. In this experiment, we investigated the basic characteristics of the apparatus, reproducibility, the change of biofilm with experimental time, the quality change of water for biofilm formation and their significance for biofilm research.

  6. Silver nanoparticles with anti microfouling effect: a study against marine biofilm forming bacteria.

    PubMed

    Inbakandan, D; Kumar, C; Abraham, L Stanley; Kirubagaran, R; Venkatesan, R; Khan, S Ajmal

    2013-11-01

    Marine biofilms are the preliminary entities due to attachment of bacteria on surfaces immersed in seawater and aggregated in a hydrated polymeric matrix. Such biofilms or microfouling play a major role in the succession of marine biofouling which attracts the larvae of barnacles, mussels and other sessile invertebrates. Different approaches have been used to prevent micro and macrofouling on marine industrial settings. Silver nanoparticles are renowned for their influential antimicrobial activity. On this back drop the present work is focused on the effect of biosynthesized silver nanoparticles against marine biofilm forming bacterial species. Aspects such as circular zone of inhibition, quantification of biofilm formation and bacterial growth were assessed for bacterial species isolated from the marine biofilm in the presence and sabsence of silver nanoparticles. The size of the circular zone formation was directly proportional to the concentration of biosynthesized silver nanoparticles that reflected the antimicrobial effect. The crystal violet staining on biofilm formation and its optical density revealed the effect on biofilm inhibition. The growth of bacteria in the presence and absence of silver nanoparticles concluded the bactericidal ability of the silver nanoparticles. However, further research is required to examine these factors. PMID:23907051

  7. Molecule Targeting Glucosyltransferase Inhibits Streptococcus mutans Biofilm Formation and Virulence.

    PubMed

    Ren, Zhi; Cui, Tao; Zeng, Jumei; Chen, Lulu; Zhang, Wenling; Xu, Xin; Cheng, Lei; Li, Mingyun; Li, Jiyao; Zhou, Xuedong; Li, Yuqing

    2015-01-01

    Dental plaque biofilms are responsible for numerous chronic oral infections and cause a severe health burden. Many of these infections cannot be eliminated, as the bacteria in the biofilms are resistant to the host's immune defenses and antibiotics. There is a critical need to develop new strategies to control biofilm-based infections. Biofilm formation in Streptococcus mutans is promoted by major virulence factors known as glucosyltransferases (Gtfs), which synthesize adhesive extracellular polysaccharides (EPS). The current study was designed to identify novel molecules that target Gtfs, thereby inhibiting S. mutans biofilm formation and having the potential to prevent dental caries. Structure-based virtual screening of approximately 150,000 commercially available compounds against the crystal structure of the glucosyltransferase domain of the GtfC protein from S. mutans resulted in the identification of a quinoxaline derivative, 2-(4-methoxyphenyl)-N-(3-{[2-(4-methoxyphenyl)ethyl]imino}-1,4-dihydro-2-quinoxalinylidene)ethanamine, as a potential Gtf inhibitor. In vitro assays showed that the compound was capable of inhibiting EPS synthesis and biofilm formation in S. mutans by selectively antagonizing Gtfs instead of by killing the bacteria directly. Moreover, the in vivo anti-caries efficacy of the compound was evaluated in a rat model. We found that the compound significantly reduced the incidence and severity of smooth and sulcal-surface caries in vivo with a concomitant reduction in the percentage of S. mutans in the animals' dental plaque (P < 0.05). Taken together, these results represent the first description of a compound that targets Gtfs and that has the capacity to inhibit biofilm formation and the cariogenicity of S. mutans. PMID:26482298

  8. The BioFilm Ring Test: a Rapid Method for Routine Analysis of Pseudomonas aeruginosa Biofilm Formation Kinetics.

    PubMed

    Olivares, Elodie; Badel-Berchoux, Stphanie; Provot, Christian; Jaulhac, Benot; Prvost, Gilles; Bernardi, Thierry; Jehl, Franois

    2016-03-01

    Currently, few techniques are available for the evaluation of bacterial biofilm adhesion. These detection tools generally require time for culture and/or arduous handling steps. In this work, the BioFilm Ring Test (BRT), a new technology, was used to estimate the biofilm formation kinetics of 25 strains of Pseudomonas aeruginosa, isolated from the sputum of cystic fibrosis (CF) patients. The principle of the new assay is based on the mobility measurement of magnetic microbeads mixed with a bacterial suspension in a polystyrene microplate. If free to move under the magnetic action, particles gather to a visible central spot in the well bottom. Therefore, the absence of spot formation in the plate reflects the bead immobilization by a biofilm in formation. The BRT device allowed us to classify the bacterial strains into three general adhesion profiles. Group 1 consists of bacteria, which are able to form a solid biofilm in <2 h. Group 2 comprises the strains that progressively set up a biofilm during 24 h. Lastly, group 3 includes the strains that stay in a planktonic form. The grouping of our strains did not differ according to culture conditions, i.e., the use of different sets of beads or culture media. The BRT is shown to be an informative tool for the characterization of biofilm-forming bacteria. Various application perspectives may be investigated for this device, such as the addition of antibiotics to the bacterial suspension to select which would have the ability to inhibit the biofilm formation. PMID:26719437

  9. The BioFilm Ring Test: a Rapid Method for Routine Analysis of Pseudomonas aeruginosa Biofilm Formation Kinetics

    PubMed Central

    Olivares, Elodie; Badel-Berchoux, Stéphanie; Provot, Christian; Jaulhac, Benoît; Prévost, Gilles; Bernardi, Thierry

    2015-01-01

    Currently, few techniques are available for the evaluation of bacterial biofilm adhesion. These detection tools generally require time for culture and/or arduous handling steps. In this work, the BioFilm Ring Test (BRT), a new technology, was used to estimate the biofilm formation kinetics of 25 strains of Pseudomonas aeruginosa, isolated from the sputum of cystic fibrosis (CF) patients. The principle of the new assay is based on the mobility measurement of magnetic microbeads mixed with a bacterial suspension in a polystyrene microplate. If free to move under the magnetic action, particles gather to a visible central spot in the well bottom. Therefore, the absence of spot formation in the plate reflects the bead immobilization by a biofilm in formation. The BRT device allowed us to classify the bacterial strains into three general adhesion profiles. Group 1 consists of bacteria, which are able to form a solid biofilm in <2 h. Group 2 comprises the strains that progressively set up a biofilm during 24 h. Lastly, group 3 includes the strains that stay in a planktonic form. The grouping of our strains did not differ according to culture conditions, i.e., the use of different sets of beads or culture media. The BRT is shown to be an informative tool for the characterization of biofilm-forming bacteria. Various application perspectives may be investigated for this device, such as the addition of antibiotics to the bacterial suspension to select which would have the ability to inhibit the biofilm formation. PMID:26719437

  10. Effect of food preservatives on in situ biofilm formation.

    PubMed

    Arweiler, Nicole Birgit; Lenz, Ronaldo; Sculean, Anton; Al-Ahmad, Ali; Hellwig, Elmar; Auschill, Thorsten Mathias

    2008-09-01

    The aim of this double-blind, controlled crossover study was to evaluate the influence of food preservatives on in situ dental biofilm growth. Twenty-four volunteers wore appliances with six specimens each of bovine enamel to build up intra-oral biofilms. During three test cycles, the subjects had to put one half of the appliance twice a day in one of the assigned active solutions (0.1% benzoate, BA; 0.1% sorbate, SA or 0.2% chlorhexidine, CHX) and the other into NaCl. After 5 days, the developed biofilms were stained with two fluorescent dyes to visualise vital (green) and dead bacteria (red). Biofilms were scanned by confocal laser scanning microscopy and biofilm thickness (BT) and bacterial vitality (BV%) were calculated. After a washout period of 7 days, a new test cycle was started. The use of SA, BA and CHX resulted in a significantly reduced BT and BV compared to NaCl (p<0.001). Differences between SA and BA were not significant (p>0.05) for both parameters, while CHX showed significantly lower values. Both preservatives showed antibacterial and plaque-inhibiting properties, but not to the extent of CHX. The biofilm model enabled the examination of undisturbed oral biofilm formation influenced by antibacterial components under clinical conditions. PMID:18357475

  11. Aminoglycoside antibiotics induce bacterial biofilm formation.

    PubMed

    Hoffman, Lucas R; D'Argenio, David A; MacCoss, Michael J; Zhang, Zhaoying; Jones, Roger A; Miller, Samuel I

    2005-08-25

    Biofilms are adherent aggregates of bacterial cells that form on biotic and abiotic surfaces, including human tissues. Biofilms resist antibiotic treatment and contribute to bacterial persistence in chronic infections. Hence, the elucidation of the mechanisms by which biofilms are formed may assist in the treatment of chronic infections, such as Pseudomonas aeruginosa in the airways of patients with cystic fibrosis. Here we show that subinhibitory concentrations of aminoglycoside antibiotics induce biofilm formation in P. aeruginosa and Escherichia coli. In P. aeruginosa, a gene, which we designated aminoglycoside response regulator (arr), was essential for this induction and contributed to biofilm-specific aminoglycoside resistance. The arr gene is predicted to encode an inner-membrane phosphodiesterase whose substrate is cyclic di-guanosine monophosphate (c-di-GMP)-a bacterial second messenger that regulates cell surface adhesiveness. We found that membranes from arr mutants had diminished c-di-GMP phosphodiesterase activity, and P. aeruginosa cells with a mutation changing a predicted catalytic residue of Arr were defective in their biofilm response to tobramycin. Furthermore, tobramycin-inducible biofilm formation was inhibited by exogenous GTP, which is known to inhibit c-di-GMP phosphodiesterase activity. Our results demonstrate that biofilm formation can be a specific, defensive reaction to the presence of antibiotics, and indicate that the molecular basis of this response includes alterations in the level of c-di-GMP. PMID:16121184

  12. Cationic Pillararenes Potently Inhibit Biofilm Formation without Affecting Bacterial Growth and Viability.

    PubMed

    Joseph, Roymon; Naugolny, Alissa; Feldman, Mark; Herzog, Ido M; Fridman, Micha; Cohen, Yoram

    2016-01-27

    It is estimated that up to 80% of bacterial infections are accompanied by biofilm formation. Since bacteria in biofilms are less susceptible to antibiotics than are bacteria in the planktonic state, biofilm-associated infections pose a major health threat, and there is a pressing need for antibiofilm agents. Here we report that water-soluble cationic pillararenes differing in the quaternary ammonium groups efficiently inhibited the formation of biofilms by clinically important Gram-positive pathogens. Biofilm inhibition did not result from antimicrobial activity; thus, the compounds should not inhibit growth of natural bacterial flora. Moreover, none of the cationic pillararenes caused detectable membrane damage to red blood cells or toxicity to human cells in culture. The results indicate that cationic pillararenes have potential for use in medical applications in which biofilm formation is a problem. PMID:26745311

  13. Evaluation of various metallic coatings on steel to mitigate biofilm formation.

    PubMed

    Kanematsu, Hideyuki; Ikigai, Hajime; Yoshitake, Michiko

    2009-02-01

    In marine environments and water systems, it is easy for many structures to form biofilms on their surfaces and to be deteriorated due to the corrosion caused by biofilm formation by bacteria. The authors have investigated the antibacterial effects of metallic elements in practical steels so far to solve food-related problems, using Escherichia coli and Staphylococcus aureus. However, from the viewpoint of material deterioration caused by bacteria and their antifouling measures, we should consider the biofilm behavior as aggregate rather than individual bacterium. Therefore, we picked up Pseudomonas aeruginosa and Pseudoalteromonas carageenovara in this study, since they easily form biofilms in estuarine and marine environments. We investigated what kind of metallic elements could inhibit the biofilm formation at first and then discussed how the thin films of those inhibitory elements on steels could affect biofilm formation. The information would lead to the establishment of effective antifouling measures against corrosion in estuarine and marine environments. PMID:19333421

  14. Biofilm formation in geometries with different surface curvature and oxygen availability

    NASA Astrophysics Data System (ADS)

    Chang, Ya-Wen; Fragkopoulos, Alexandros A.; Marquez, Samantha M.; Kim, Harold D.; Angelini, Thomas E.; Fernández-Nieves, Alberto

    2015-03-01

    Bacteria in the natural environment exist as interface-associated colonies known as biofilms . Complex mechanisms are often involved in biofilm formation and development. Despite the understanding of the molecular mechanisms involved in biofilm formation, it remains unclear how physical effects in standing cultures influence biofilm development. The topology of the solid interface has been suggested as one of the physical cues influencing bacteria-surface interactions and biofilm development. Using the model organism Bacillus subtilis, we study the transformation of swimming bacteria in liquid culture into robust biofilms in a range of confinement geometries (planar, spherical and toroidal) and interfaces (air/water, silicone/water, and silicone elastomer/water). We find that B. subtilis form submerged biofilms at both solid and liquid interfaces in addition to air-water pellicles. When confined, bacteria grow on curved surfaces of both positive and negative Gaussian curvature. However, the confinement geometry does affect the resulting biofilm roughness and relative coverage. We also find that the biofilm location is governed by oxygen availability as well as by gravitational effects; these compete with each other in some situations. Overall, our results demonstrate that confinement geometry is an effective way to control oxygen availability and subsequently biofilm growth.

  15. 1,5-Anhydro-D-fructose: A natural antibiotic that inhibits the growth of gram-positive bacteria and microbial biofilm formation to prevent nosocomial infection

    PubMed Central

    MENG, XIAOJIE; KAWAHARA, KO-ICHI; MIYANOHARA, HIROAKI; YOSHIMOTO, YASUSHI; YOSHINAGA, KAZUHIRO; NOMA, SATOSHI; KIKUCHI, KIYOSHI; MORIMOTO, YOKO; ITO, TAKASHI; OYAMA, YOKO; YOSHINAGA, NARIMASA; SHRESTHA, BINITA; CHANDAN, BINITA; MERA, KENTARO; TADA, KO-ICHI; MIURA, NAOKI; ONO, YOSHIKO; TAKENOUCHI, KAZUNORI; MAENOSONO, RYUICHI; NAGASATO, TOMOKA; HASHIGUCHI, TERUTO; MARUYAMA, IKURO

    2011-01-01

    Nosocomial infections caused by microbial opportunistic infections or microbial biofilms may occur during hospitalization and increase patient morbidity, mortality and health care costs. Artificial antibiotic agents were initially used to prevent infection; however, the high prevalence of nosocomial infections has resulted in their excessive use, which has led to microbial resistance to these agents. The increase in microbial resistance to antibiotics and the development of antibiotic agents may be the cause of the production of other microbial resistance. Thus, natural compounds that have no adverse side effects would be a preferred treatment modality. Recently, the monosaccharide 1,5-anhydro-D-fructose (1,5-AF), a natural plant compound derived from starch, has been found to have multifunctional properties, including antioxidant, antiplatelet aggregation by thrombin and anti-inflammatory activities. The results of the present study demonstrate that 1,5-AF suppressed the growth of coagulase-negative staphylococci on the hands as well as the growth of Staphylococcus epidermidis, which is a cause of opportunistic infections. Furthermore, 1,5-AF suppressed biofilm formation by the methicillin-resistant Staphylococcus aureus. In conclusion, 1,5-AF is a natural compound that may be effective in preventing nosocomial infections, without causing adverse side effects. PMID:22977551

  16. 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

  17. 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. PMID:26001706

  18. Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation

    PubMed Central

    Laverty, Garry; Gorman, Sean P.; Gilmore, Brendan F.

    2014-01-01

    Pseudomonas aeruginosa and Escherichia coli are the most prevalent Gram-negative biofilm forming medical device associated pathogens, particularly with respect to catheter associated urinary tract infections. In a similar manner to Gram-positive bacteria, Gram-negative biofilm formation is fundamentally determined by a series of steps outlined more fully in this review, namely adhesion, cellular aggregation, and the production of an extracellular polymeric matrix. More specifically this review will explore the biosynthesis and role of pili and flagella in Gram-negative adhesion and accumulation on surfaces in Pseudomonas aeruginosa and Escherichia coli. The process of biofilm maturation is compared and contrasted in both species, namely the production of the exopolysaccharides via the polysaccharide synthesis locus (Psl), pellicle Formation (Pel) and alginic acid synthesis in Pseudomonas aeruginosa, and UDP-4-amino-4-deoxy-l-arabinose and colonic acid synthesis in Escherichia coli. An emphasis is placed on the importance of the LuxR homologue sdiA; the luxS/autoinducer-II; an autoinducer-III/epinephrine/norepinephrine and indole mediated Quorum sensing systems in enabling Gram-negative bacteria to adapt to their environments. The majority of Gram-negative biofilms consist of polysaccharides of a simple sugar structure (either homo- or heteropolysaccharides) that provide an optimum environment for the survival and maturation of bacteria, allowing them to display increased resistance to antibiotics and predation. PMID:25438014

  19. Biofilm formation by Stenotrophomonas maltophilia isolates from device-associated nosocomial infections.

    PubMed

    Passerini de Rossi, B; Calenda, M; Vay, C; Franco, M

    2007-01-01

    Medical devices are often colonized by bacteria which may cause severe infections. The aim of this work was to evaluate biofilm formation by S. maltophilia isolates from device-associated nosocomial infections. The 13 local isolates exhibited different capacities of biofilm formation on hydrophilic and hydrophobic surfaces. All isolates formed strong biofilms in polystyrene microplates, while strong, moderate or weak biofilms were detected in borosilicate (BS) or polypropylene (PP) tubes. The proficiency of biofilm formation was better evaluated by the level of crystal violet staining expressed relative to the final culture density. The microscopic analysis of biofilms formed on glass coverslips revealed the presence of a matrix of exopolysaccharides and microcolonies typical of biofilm architecture. Isolates with increased adhesion to BS showed larger microcolonies. According to our results, twitching correlated well with attachment to the three abiotic surfaces tested, while swimming only showed a slight correlation with biofilm formation on PP. Poor correlation was observed between cell surface hydrophobicity and biofilm formation. One of the highest biofilm-producing isolates adhered to urethral catheters of different materials, and exhibited an increased resistance to oxidative stress, one of the common stresses encountered by bacteria during the infection process due to the immune response. PMID:18390153

  20. Application of micro-PIV to the study of staphylococci bacteria bio-film dynamics

    NASA Astrophysics Data System (ADS)

    Sherman, Erica; Bayles, Kenneth; Moormeier, Derek; Wei, Timothy

    2012-11-01

    Staphylococci bacteria are recognized as the most frequent cause of biofilm-associated infections. Although humans are regularly exposed to staphylococcus bacteria without consequence, a localized staph infection has the potential to enter the bloodstream and lead to serious infections such as endocarditis, pneumonia, or toxic shock syndrome. The mechanics of staphylococci biofilm formation and dispersion through the bloodstream are not well known. It has recently been observed that under certain flow conditions, bacteria grow in stable bio-films. Under other conditions, they organize in tower-like structures which break and are transported downstream by the flow. The fundamental questions addressed in this study are i) whether or not fluid mechanics plays a role in differentiating between film or tower formation and ii) whether or not the faulty towers are a bio-film propagation mechanism. This talk focuses on the application of micro-PIV to study this problem. Bacteria were cultured in a glass microchannel and subjected to a range of steady shear rates. Micro-PIV measurements were made to map the flow over and around different types of bio-film structures. Measurements and control volume analysis will be presented quantifying forces acting on these structures.

  1. A direct viable count method for the enumeration of attached bacteria and assessment of biofilm disinfection

    NASA Technical Reports Server (NTRS)

    Yu, F. P.; Pyle, B. H.; McFeters, G. A.

    1993-01-01

    This report describes the adaptation of an in situ direct viable count (in situ DVC) method in biofilm disinfection studies. The results obtained with this technique were compared to two other enumeration methods, the plate count (PC) and conventional direct viable count (c-DVC). An environmental isolate (Klebsiella pneumoniae Kp1) was used to form biofilms on stainless steel coupons in a stirred batch reactor. The in situ DVC method was applied to directly assess the viability of bacteria in biofilms without disturbing the integrity of the interfacial community. As additional advantages, the results were observed after 4 h instead of the 24 h incubation time required for colony formation and total cell numbers that remained on the substratum were enumerated. Chlorine and monochloramine were used to determine the susceptibilities of attached and planktonic bacteria to disinfection treatment using this novel analytical approach. The planktonic cells in the reactor showed no significant change in susceptibility to disinfectants during the period of biofilm formation. In addition, the attached cells did not reveal any more resistance to disinfection than planktonic cells. The disinfection studies of young biofilms indicated that 0.25 mg/l free chlorine (at pH 7.2) and 1 mg/l monochloramine (at pH 9.0) have comparable disinfection efficiencies at 25 degrees C. Although being a weaker disinfectant, monochloramine was more effective in removing attached bacteria from the substratum than free chlorine. The in situ DVC method always showed at least one log higher viable cell densities than the PC method, suggesting that the in situ DVC method is more efficient in the enumeration of biofilm bacteria. The results also indicated that the in situ DVC method can provide more accurate information regarding the cell numbers and viability of bacteria within biofilms following disinfection.

  2. Chemotaxis in P. Aeruginosa Biofilm Formation

    NASA Astrophysics Data System (ADS)

    Bienvenu, Samuel; Strain, Shinji; Thatcher, Travis; Gordon, Vernita

    2010-10-01

    Pseudomonas biofilms form infections in the lungs of Cystic Fibrosis (CF) patients that damage lung tissue and lead to death. Previous work shows chemotaxis is important for Pseudomonas in CF lungs. The work studied swimming bacteria at high concentrations. In contrast, medically relevant biofilms initiate from sparse populations of surface-bound bacteria. The recent development of software techniques for automated, high-throughput bacteria tracking leaves us well-poised to quantitatively study these chemotactic conditions. We will develop experimental systems for such studies, focusing on L-Arginine (an amino acid), D-Galactose (a sugar present in lungs), and succinate and glucose (carbon sources for bacteria). This suite of chemoattractants will allow us to study how chemoattractant characteristics--size and diffusion behavior--change bacterial response; the interaction of competing chemoattractants; and, differences in bacterial behaviors, like motility modes, in response to different types of chemoattractions and varying neighbor cell density.

  3. Inhibitory effect of Lactobacillus salivarius on Streptococcus mutans biofilm formation.

    PubMed

    Wu, C-C; Lin, C-T; Wu, C-Y; Peng, W-S; Lee, M-J; Tsai, Y-C

    2015-02-01

    Dental caries arises from an imbalance of metabolic activities in dental biofilms developed primarily by Streptococcus mutans. This study was conducted to isolate potential oral probiotics with antagonistic activities against S. mutans biofilm formation from Lactobacillus salivarius, frequently found in human saliva. We analysed 64 L. salivarius strains and found that two, K35 and K43, significantly inhibited S. mutans biofilm formation with inhibitory activities more pronounced than those of Lactobacillus rhamnosus GG (LGG), a prototypical probiotic that shows anti-caries activity. Scanning electron microscopy showed that co-culture of S. mutans with K35 or K43 resulted in significantly reduced amounts of attached bacteria and network-like structures, typically comprising exopolysaccharides. Spot assay for S. mutans indicated that K35 and K43 strains possessed a stronger bactericidal activity against S. mutans than LGG. Moreover, quantitative real-time polymerase chain reaction showed that the expression of genes encoding glucosyltransferases, gtfB, gtfC, and gtfD was reduced when S. mutans were co-cultured with K35 or K43. However, LGG activated the expression of gtfB and gtfC, but did not influence the expression of gtfD in the co-culture. A transwell-based biofilm assay indicated that these lactobacilli inhibited S. mutans biofilm formation in a contact-independent manner. In conclusion, we identified two L. salivarius strains with inhibitory activities on the growth and expression of S. mutans virulence genes to reduce its biofilm formation. This is not a general characteristic of the species, so presents a potential strategy for in vivo alteration of plaque biofilm and caries. PMID:24961744

  4. Fourier transform-infrared spectroscopic methods for microbial ecology: analysis of bacteria, bacteria-polymer mixtures and biofilms

    NASA Technical Reports Server (NTRS)

    Nichols, P. D.; Henson, J. M.; Guckert, J. B.; Nivens, D. E.; White, D. C.

    1985-01-01

    Fourier transform-infrared (FT-IR) spectroscopy has been used to rapidly and nondestructively analyze bacteria, bacteria-polymer mixtures, digester samples and microbial biofilms. Diffuse reflectance FT-IR (DRIFT) analysis of freeze-dried, powdered samples offered a means of obtaining structural information. The bacteria examined were divided into two groups. The first group was characterized by a dominant amide I band and the second group of organisms displayed an additional strong carbonyl stretch at approximately 1740 cm-1. The differences illustrated by the subtraction spectra obtained for microbes of the two groups suggest that FT-IR spectroscopy can be utilized to recognize differences in microbial community structure. Calculation of specific band ratios has enabled the composition of bacteria and extracellular or intracellular storage product polymer mixtures to be determined for bacteria-gum arabic (amide I/carbohydrate C-O approximately 1150 cm-1) and bacteria-poly-beta-hydroxybutyrate (amide I/carbonyl approximately 1740 cm-1). The key band ratios correlate with the compositions of the material and provide useful information for the application of FT-IR spectroscopy to environmental biofilm samples and for distinguishing bacteria grown under differing nutrient conditions. DRIFT spectra have been obtained for biofilms produced by Vibrio natriegens on stainless steel disks. Between 48 and 144 h, an increase in bands at approximately 1440 and 1090 cm-1 was seen in FT-IR spectra of the V. natriegens biofilm. DRIFT spectra of mixed culture effluents of anaerobic digesters show differences induced by shifts in input feedstocks. The use of flow-through attenuated total reflectance has permitted in situ real-time changes in biofilm formation to be monitored and provides a powerful tool for understanding the interactions within adherent microbial consortia.

  5. Fractal analysis of Xylella fastidiosa biofilm formation

    NASA Astrophysics Data System (ADS)

    Moreau, A. L. D.; Lorite, G. S.; Rodrigues, C. M.; Souza, A. A.; Cotta, M. A.

    2009-07-01

    We have investigated the growth process of Xylella fastidiosa biofilms inoculated on a glass. The size and the distance between biofilms were analyzed by optical images; a fractal analysis was carried out using scaling concepts and atomic force microscopy images. We observed that different biofilms show similar fractal characteristics, although morphological variations can be identified for different biofilm stages. Two types of structural patterns are suggested from the observed fractal dimensions Df. In the initial and final stages of biofilm formation, Df is 2.730.06 and 2.680.06, respectively, while in the maturation stage, Df=2.570.08. These values suggest that the biofilm growth can be understood as an Eden model in the former case, while diffusion-limited aggregation (DLA) seems to dominate the maturation stage. Changes in the correlation length parallel to the surface were also observed; these results were correlated with the biofilm matrix formation, which can hinder nutrient diffusion and thus create conditions to drive DLA growth.

  6. Inhibition of Biofilm Formation by T7 Bacteriophages Producing Quorum-Quenching Enzymes

    PubMed Central

    Lamas-Samanamud, Gisella R.

    2014-01-01

    Bacterial growth in biofilms is the major cause of recalcitrant biofouling in industrial processes and of persistent infections in clinical settings. The use of bacteriophage treatment to lyse bacteria in biofilms has attracted growing interest. In particular, many natural or engineered phages produce depolymerases to degrade polysaccharides in the biofilm matrix and allow access to host bacteria. However, the phage-produced depolymerases are highly specific for only the host-derived polysaccharides and may have limited effects on natural multispecies biofilms. In this study, an engineered T7 bacteriophage was constructed to encode a lactonase enzyme with broad-range activity for quenching of quorum sensing, a form of bacterial cell-cell communication via small chemical molecules (acyl homoserine lactones [AHLs]) that is necessary for biofilm formation. Our results demonstrated that the engineered T7 phage expressed the AiiA lactonase to effectively degrade AHLs from many bacteria. Addition of the engineered T7 phage to mixed-species biofilms containing Pseudomonas aeruginosa and Escherichia coli resulted in inhibition of biofilm formation. Such quorum-quenching phages that can lyse host bacteria and express quorum-quenching enzymes to affect diverse bacteria in biofilm communities may become novel antifouling and antibiofilm agents in industrial and clinical settings. PMID:24951790

  7. New derivatives of dehydroabietic acid target planktonic and biofilm bacteria in Staphylococcus aureus and effectively disrupt bacterial membrane integrity.

    PubMed

    Manner, Suvi; Vahermo, Mikko; Skogman, Malena E; Krogerus, Sara; Vuorela, Pia M; Yli-Kauhaluoma, Jari; Fallarero, Adyary; Moreira, Vânia M

    2015-09-18

    The combination of the dehydroabietic acid scaffold with different amino acids resulted in the discovery of a new class of hybrid compounds that targets both planktonic and biofilms bacteria in Staphylococcus aureus strains and are far more potent anti-biofilm agents than conventional antibiotics. Unlike dehydroabietic acid, these compounds can disrupt biofilms within a short time period and compromise the integrity of the bacterial membrane. Two of the compounds identified in our study are the most potent abietane-type anti-biofilm agents reported so far and display robust activity against pre-formed biofilms at concentrations only 3-6-fold higher than those required to inhibit biofilm formation. Their easy preparation based on proteolysis-resistant d- and unusual amino acids makes them useful chemical probes to gain a deeper understanding of bacterial biofilms and outstanding candidates for further development into new drugs to fight infections. PMID:26241878

  8. Acetic Acid Acts as a Volatile Signal To Stimulate Bacterial Biofilm Formation

    PubMed Central

    Chen, Yun; Gozzi, Kevin; Yan, Fang

    2015-01-01

    ABSTRACT Volatiles are small air-transmittable chemicals with diverse biological activities. In this study, we showed that volatiles produced by the bacterium Bacillus subtilis had a profound effect on biofilm formation of neighboring B. subtilis cells that grew in proximity but were physically separated. We further demonstrated that one such volatile, acetic acid, is particularly potent in stimulating biofilm formation. Multiple lines of genetic evidence based on B. subtilis mutants that are defective in either acetic acid production or transportation suggest that B. subtilis uses acetic acid as a metabolic signal to coordinate the timing of biofilm formation. Lastly, we investigated how B. subtilis cells sense and respond to acetic acid in regulating biofilm formation. We showed the possible involvement of three sets of genes (ywbHG, ysbAB, and yxaKC), all encoding putative holin-antiholin-like proteins, in cells responding to acetic acid and stimulating biofilm formation. All three sets of genes were induced by acetate. A mutant with a triple mutation of those genes showed a severe delay in biofilm formation, whereas a strain overexpressing ywbHG showed early and robust biofilm formation. Results of our studies suggest that B. subtilis and possibly other bacteria use acetic acid as a metabolic signal to regulate biofilm formation as well as a quorum-sensing-like airborne signal to coordinate the timing of biofilm formation by physically separated cells in the community. PMID:26060272

  9. [Biofilm formation capacity of Listeria monocytogens strains isolated from soft cheese from Costa Rica].

    PubMed

    Carrillo Zeledn, Gabriela; Redondo Solano, Mauricio; Arias Echandi, Mara Laura

    2010-06-01

    Listeria monocytogenes is a bacteria associated with the production of severe infectious disease in human being, but also with the formation of biofilms in different surfaces related to the food production environment. Biofilm represents a serious problem in food industry, since it is a constant and important contamination source and also, bacteria present in it have an increased resistance towards physical and chemical agents of common use. The capacity of biofilm formation of L. monocytogenes strains previously isolated from soft cheese samples from Costa Rica was studied under different temperature and culture conditions. The microplate technique was performed using different culture media (BHIB, TSB 1:20 and cheese serum) and at different incubation temperatures (refrigeration, environmental and 35 degrees C). Biofilm formation capacity was classified according to the optical density obtained at 620 nm. None of the strains evaluated was classified as strong biofilm former under any of the variables studied, nevertheless, weak and moderate formers were detected. The results obtained show the influence of the nutrient content of the culture media used over biofilm formation; BHIB was the only culture media that allowed the expression of moderate biofilm forms, contrary to cheese serum that did not promote biofilm production. Biofilm formation is a multifactorial process, where adsorption level depends on several variables and its study must be promoted in order to develop methodologies that allow its reduction or elimination, so food industries may offer safe food products to consumers. PMID:21427885

  10. 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. PMID:25406229

  11. Embedded Biofilm, a New Biofilm Model Based on the Embedded Growth of Bacteria

    PubMed Central

    Jung, Yong-Gyun; Choi, Jungil; Kim, Soo-Kyoung

    2014-01-01

    A variety of systems have been developed to study biofilm formation. However, most systems are based on the surface-attached growth of microbes under shear stress. In this study, we designed a microfluidic channel device, called a microfluidic agarose channel (MAC), and found that microbial cells in the MAC system formed an embedded cell aggregative structure (ECAS). ECASs were generated from the embedded growth of bacterial cells in an agarose matrix and better mimicked the clinical environment of biofilms formed within mucus or host tissue under shear-free conditions. ECASs were developed with the production of extracellular polymeric substances (EPS), the most important feature of biofilms, and eventually burst to release planktonic cells, which resembles the full developmental cycle of biofilms. Chemical and genetic effects have also confirmed that ECASs are a type of biofilm. Unlike the conventional biofilms formed in the flow cell model system, this embedded-type biofilm completes the developmental cycle in only 9 to 12 h and can easily be observed with ordinary microscopes. We suggest that ECASs are a type of biofilm and that the MAC is a system for observing biofilm formation. PMID:25326307

  12. d-Amino acids do not inhibit biofilm formation in Staphylococcus aureus.

    PubMed

    Sarkar, Sourav; Pires, Marcos M

    2015-01-01

    Bacteria can either exist in the planktonic (free floating) state or in the biofilm (encased within an organic framework) state. Bacteria biofilms cause industrial concerns and medical complications and there has been a great deal of interest in the discovery of small molecule agents that can inhibit the formation of biofilms or disperse existing structures. Herein we show that, contrary to previously published reports, d-amino acids do not inhibit biofilm formation of Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), and Staphylococcus epidermis (S. epidermis) at millimolar concentrations. We evaluated a diverse set of natural and unnatural d-amino acids and observed no activity from these compounds in inhibiting biofilm formation. PMID:25658642

  13. Bacterial aggregation and biofilm formation in a vortical flow

    PubMed Central

    Yazdi, Shahrzad; Ardekani, Arezoo M.

    2012-01-01

    Bacterial aggregation and patchiness play an important role in a variety of ecological processes such as competition, adaptation, epidemics, and succession. Here, we demonstrate that hydrodynamics of their environment can lead to their aggregation. This is specially important since microbial habitats are rarely at rest (e.g., ocean, blood stream, flow in porous media, and flow through membrane filtration processes). In order to study the dynamics of bacterial collection in a vortical flow, we utilize a microfluidic system to mimic some of the important microbial conditions at ecologically relevant spatiotemporal scales. We experimentally demonstrate the formation of “ring”-shaped bacterial collection patterns and subsequently the formation of biofilm streamers in a microfluidic system. Acoustic streaming of a microbubble is used to generate a vortical flow in a microchannel. Due to bacteria's finite-size, the microorganisms are directed to closed streamlines and trapped in the vortical flow. The collection of bacteria in the vortices occurs in a matter of seconds, and unexpectedly, triggers the formation of biofilm streamers within minutes. Swimming bacteria have a competitive advantage to respond to their environmental conditions. In order to investigate the role of bacterial motility on the rate of collection, two strains of Escherichia coli bacteria with different motilities are used. We show that the bacterial collection in a vortical flow is strongly pronounced for high motile bacteria. PMID:24339847

  14. Bacterial aggregation and biofilm formation in a vortical flow.

    PubMed

    Yazdi, Shahrzad; Ardekani, Arezoo M

    2012-01-01

    Bacterial aggregation and patchiness play an important role in a variety of ecological processes such as competition, adaptation, epidemics, and succession. Here, we demonstrate that hydrodynamics of their environment can lead to their aggregation. This is specially important since microbial habitats are rarely at rest (e.g., ocean, blood stream, flow in porous media, and flow through membrane filtration processes). In order to study the dynamics of bacterial collection in a vortical flow, we utilize a microfluidic system to mimic some of the important microbial conditions at ecologically relevant spatiotemporal scales. We experimentally demonstrate the formation of "ring"-shaped bacterial collection patterns and subsequently the formation of biofilm streamers in a microfluidic system. Acoustic streaming of a microbubble is used to generate a vortical flow in a microchannel. Due to bacteria's finite-size, the microorganisms are directed to closed streamlines and trapped in the vortical flow. The collection of bacteria in the vortices occurs in a matter of seconds, and unexpectedly, triggers the formation of biofilm streamers within minutes. Swimming bacteria have a competitive advantage to respond to their environmental conditions. In order to investigate the role of bacterial motility on the rate of collection, two strains of Escherichia coli bacteria with different motilities are used. We show that the bacterial collection in a vortical flow is strongly pronounced for high motile bacteria. PMID:24339847

  15. The inhibitory effect of Thymus vulgaris extracts on the planktonic form and biofilm structures of six human pathogenic bacteria

    PubMed Central

    Mohsenipour, Zeinab; Hassanshahian, Mehdi

    2015-01-01

    Objective: Microorganisms are responsible for many problems in industry and medicine because of biofilm formation. Therefore, this study was aimed to examine the effect of Thymus vulgaris (T. vulgaris) extracts on the planktonic form and biofilm structures of six pathogenic bacteria. Materials and methods: Antimicrobial activities of the plant extracts against the planktonic form of the bacteria were determined using the disc diffusion method. MIC and MBC values were evaluated using macrobroth dilution technique. Anti-biofilm effects were assessed by microtiter plate method. Results: According to disc diffusion test (MIC and MBC), the ability of Thymus vulgaris (T. vulgaris ) extracts for inhibition of bacteria in planktonic form was confirmed. In dealing with biofilm structures, the inhibitory effect of the extracts was directly correlated to their concentration. Except for the inhibition of biofilm formation, efficacy of each extract was independent from type of solvent. Conclusion: According to the potential of Thymus vulgaris (T. vulgaris) extracts to inhibit the test bacteria in planktonic and biofilm form, it can be suggested that Thymus vulgaris (T. vulgaris) extracts can be applied as antimicrobial agents against the pathogenic bacteria particularly in biofilm forms. PMID:26442753

  16. Numerical simulation of wrinkle morphology formation and the evolution of different Bacillus subtilis biofilms.

    PubMed

    Wang, Xiaoling; Hao, Mudong; Wang, Guoqing

    2016-01-01

    Wrinkle morphology is a distinctive phenomenon observed in mature biofilms that are produced by a great number of bacteria. The wrinkle pattern depends on the mechanical properties of the agar substrate and the biofilm itself, governed by the extracellular matrix (ECM). Here we study the macroscopic structures and the evolution of Bacillus subtilis biofilm wrinkles using the commercial finite element software ABAQUS. A mechanical model and simulation are set up to analyze and evaluate bacteria biofilm's wrinkle characteristics. We uncover the wrinkle formation mechanism and enumerate the quantitative relationship between wrinkle structure and mechanical properties of biofilm and its substrate. Our work can be used to modify the wrinkle pattern and control the biofilm size. PMID:26877034

  17. Implications of Biofilm Formation on Urological Devices

    NASA Astrophysics Data System (ADS)

    Cadieux, Peter A.; Wignall, Geoffrey R.; Carriveau, Rupp; Denstedt, John D.

    2008-09-01

    Despite millions of dollars and several decades of research targeted at their prevention and eradication, biofilm-associated infections remain the major cause of urological device failure. Numerous strategies have been aimed at improving device design, biomaterial composition, surface properties and drug delivery, but have been largely circumvented by microbes and their plethora of attachment, host evasion, antimicrobial resistance, and dissemination strategies. This is not entirely surprising since natural biofilm formation has been going on for millions of years and remains a major part of microorganism survival and evolution. Thus, the fact that biofilms develop on and in the biomaterials and tissues of humans is really an extension of this natural tendency and greatly explains why they are so difficult for us to combat. Firstly, biofilm structure and composition inherently provide a protective environment for microorganisms, shielding them from the shear stress of urine flow, immune cell attack and some antimicrobials. Secondly, many biofilm organisms enter a metabolically dormant state that renders them tolerant to those antibiotics and host factors able to penetrate the biofilm matrix. Lastly, the majority of organisms that cause biofilm-associated urinary tract infections originate from our own oral cavity, skin, gastrointestinal and urogenital tracts and therefore have already adapted to many of our host defenses. Ultimately, while biofilms continue to hold an advantage with respect to recurrent infections and biomaterial usage within the urinary tract, significant progress has been made in understanding these dynamic microbial communities and novel approaches offer promise for their prevention and eradication. These include novel device designs, antimicrobials, anti-adhesive coatings, biodegradable polymers and biofilm-disrupting compounds and therapies.

  18. Biofilm formation of Francisella noatunensis subsp. orientalis.

    PubMed

    Soto, Esteban; Halliday-Simmonds, Iona; Francis, Stewart; Kearney, Michael T; Hansen, John D

    2015-12-31

    Francisella noatunensis subsp. orientalis (Fno) is an emergent fish pathogen in both marine and fresh water environments. The bacterium is suspected to persist in the environment even without the presence of a suitable fish host. In the present study, the influence of different abiotic factors such as salinity and temperature were used to study the biofilm formation of different isolates of Fno including intracellular growth loci C (iglC) and pathogenicity determinant protein A (pdpA) knockout strains. Finally, we compared the susceptibility of planktonic and biofilm to three disinfectants used in the aquaculture and ornamental fish industry, namely Virkon(), bleach and hydrogen peroxide. The data indicates that Fno is capable of producing biofilms within 24h where both salinity as well as temperature plays a role in the growth and biofilm formation of Fno. Mutations in the iglC or pdpA, both known virulence factors, do not appear to affect the capacity of Fno to produce biofilms, and the minimum inhibitory concentration, and minimum biocidal concentration for the three disinfectants were lower than the minimum biofilm eradication concentration values. This information needs to be taken into account if trying to eradicate the pathogen from aquaculture facilities or aquariums. PMID:26507830

  19. Biofilm formation of Francisella noatunensis subsp. orientalis

    USGS Publications Warehouse

    Soto, Esteban; Halliday-Wimmonds, Iona; Kearney, Michael T; Hansen, John D.

    2015-01-01

    Francisella noatunensis subsp. orientalis (Fno) is an emergent fish pathogen in both marine and fresh water environments. The bacterium is suspected to persist in the environment even without the presence of a suitable fish host. In the present study, the influence of different abiotic factors such as salinity and temperature were used to study the biofilm formation of different isolates of Fno including intracellular growth loci C (iglC) and pathogenicity determinant protein A (pdpA) knockout strains. Finally, we compared the susceptibility of planktonic and biofilm to three disinfectants used in the aquaculture and ornamental fish industry, namely Virkon®, bleach and hydrogen peroxide. The data indicates that Fno is capable of producing biofilms within 24 h where both salinity as well as temperature plays a role in the growth and biofilm formation of Fno. Mutations in the iglC or pdpA, both known virulence factors, do not appear to affect the capacity of Fno to produce biofilms, and the minimum inhibitory concentration, and minimum biocidal concentration for the three disinfectants were lower than the minimum biofilm eradication concentration values. This information needs to be taken into account if trying to eradicate the pathogen from aquaculture facilities or aquariums.

  20. Fluorescence-Based Quasicontinuous and In Situ Monitoring of Biofilm Formation Dynamics in Natural Marine Environments

    PubMed Central

    Friedrichs, G.; Lachnit, T.

    2014-01-01

    Analyzing the dynamics of biofilm formation helps to deepen our understanding of surface colonization in natural environments. While methods for screening biofilm formation in the laboratory are well established, studies in marine environments have so far been based upon destructive analysis of individual samples and provide only discontinuous snapshots of biofilm establishment. In order to explore the development of biofilm over time and under various biotic and abiotic conditions, we applied a recently developed optical biofilm sensor to quasicontinuously analyze marine biofilm dynamics in situ. Using this technique in combination with microscope-assisted imaging, we investigated biofilm formation from its beginning to mature multispecies biofilms. In contrast to laboratory studies on biofilm formation, a smooth transition from initial attachment to colony formation and exponential growth could not be observed in the marine environment. Instead, initial attachment was followed by an adaptation phase of low growth and homogeneously distributed solitary bacterial cells. Moreover, we observed a diurnal variation of biofilm signal intensity, suggesting a transient state of biofilm formation of bacteria. Overall, the biofilm formation dynamics could be modeled by three consecutive development stages attributed to initial bacterial attachment, bacterial growth, and attachment and growth of unicellular eukaryotic microorganisms. Additional experiments showed that the presence of seaweed considerably shortened the adaptation phase in comparison with that on control surfaces but yielded similar growth rates. The outlined examples highlight the advantages of a quasicontinuous in situ detection that enabled, for the first time, the exploration of the initial attachment phase and the diurnal variation during biofilm formation in natural ecosystems. PMID:24727266

  1. Aquatic plants stimulate the growth of and biofilm formation by Mycobacterium ulcerans in axenic culture and harbor these bacteria in the environment.

    PubMed

    Marsollier, Laurent; Stinear, Timothy; Aubry, Jacques; Saint Andr, Jean Paul; Robert, Raymond; Legras, Pierre; Manceau, Anne-Lise; Audrain, Christine; Bourdon, Sandra; Kouakou, Henri; Carbonnelle, Bernard

    2004-02-01

    Mycobacterium ulcerans is the causative agent of Buruli ulcer, one of the most common mycobacterial diseases of humans. Recent studies have implicated aquatic insects in the transmission of this pathogen, but the contributions of other elements of the environment remain largely unknown. We report here that crude extracts from two green algae added to the BACTEC 7H12B culture medium halved the doubling time of M. ulcerans and promoted biofilm formation. Using the 7H12B medium, modified by the addition of the algal extract, and immunomagnetic separation, we also demonstrate that M. ulcerans is associated with aquatic plants in an area of the Ivory Coast where Buruli ulcer is endemic. Genotype analysis showed that plant-associated M. ulcerans had the same profile as isolates recovered in the same region from both aquatic insects and clinical specimens. These observations implicate aquatic plants as a reservoir of M. ulcerans and add a new potential link in the chain of transmission of M. ulcerans to humans. PMID:14766593

  2. Real-time monitoring of the adherence of Streptococcus anginosus group bacteria to extracellular matrix decorin and biglycan proteoglycans in biofilm formation.

    PubMed

    Landrygan-Bakri, Janine; Wilson, Melanie J; Williams, David W; Lewis, Michael A O; Waddington, Rachel J

    2012-07-01

    Members of the Streptococcus anginosus group (SAGs) are significant pathogens. However, their pathogenic mechanisms are incompletely understood. This study investigates the adherence of SAGs to the matrix proteoglycans decorin and biglycan of soft gingival and alveolar bone. Recombinant chondroitin 4-sulphate(C4S)-conjugated decorin and biglycan were synthesised using mammalian expression systems. C4S-conjugated decorin/biglycan and dermatan sulphate (DS) decorin/biglycan were isolated from ovine alveolar bone and gingival connective tissue, respectively. Using surface plasmon resonance, adherence of the SAGs S. anginosus, Streptococcus constellatus and Streptococcus intermedius to immobilised proteoglycan was assessed as a function of real-time biofilm formation. All isolates adhered to gingival proteoglycan, 59% percent of isolates adhered to alveolar proteoglycans, 70% to recombinant decorin and 76% to recombinant biglycan. Higher adherence was generally noted for S. constellatus and S. intermedius isolates. No differences in adherence were noted between commensal and pathogenic strains to decorin or biglycan. DS demonstrated greater adherence compared to C4S. Removal of the glycosaminoglycan chains with chondroitinase ABC resulted in no or minimal adherence for all isolates. These results suggest that SAGs bind to the extracellular matrix proteoglycans decorin and biglycan, with interaction mediated by the conjugated glycosaminoglycan chain. PMID:22835945

  3. Murine solid tumours as a novel model to study bacterial biofilm formation in vivo.

    PubMed

    Pawar, V; Crull, K; Komor, U; Kasnitz, N; Frahm, M; Kocijancic, D; Westphal, K; Leschner, S; Wolf, K; Loessner, H; Rohde, M; Hussler, S; Weiss, S

    2014-08-01

    Bacteria of many species are able to invade and colonize solid tumours in mice. We have focused on Salmonella enterica serovar Typhimurium. Detailed analysis revealed that such tumour-invading Salmonella form biofilms, thus providing a versatile in vivo test system for studying bacterial phenotypes and host-pathogen interactions. It appears that biofilm formation by S.typhimurium is induced as a defence against the immune system of the host, and in particular against neutrophils. Further, we extended our work to the clinically more relevant biofilm infection by Pseudomonas aeruginosa. The induction of P.aeruginosa biofilms in neoplastic tissue appears to be elicited as a reaction against the immune system. Reconstitution experiments reveal that T cells are responsible for biofilm induction. Isogenic mutants that are no longer able to form biofilms can be used for comparison studies to determine antimicrobial resistance, especially therapeutic efficacy against P.aeruginosa located in biofilms. PMID:24724621

  4. Measurement of fluid dynamic loading on staphylococci bacteria bio-film structures using μPIV

    NASA Astrophysics Data System (ADS)

    Sherman, Erica; Moormeier, Derek; Bayles, Kenneth; Davidson, John; Ryu, Sangjin; Wei, Timothy

    2013-11-01

    Staphylococci bacteria are recognized as the most frequent cause of biofilm-associated infections. Although humans are regularly exposed to these bacteria without consequence, a localized infection can enter the bloodstream and lead to serious infections such as endocarditis, pneumonia, or toxic shock syndrome. The mechanics of staphylococci biofilm formation and dispersion through the bloodstream are not well known. It has recently been observed that under certain flow conditions, bacteria organize in tower-like structures which break and are transported downstream by the flow. The fundamental questions of interest are i) whether or not fluid mechanics plays a role in differentiating between film or tower formation and ii) whether or not the faulty towers are a bio-film propagation mechanism. This talk focuses on the application of μPIV to study this problem. Staphylococcus aureus bacteria were cultured in the Bioflux Fluxion square microchannel of a 65 by 65 um cross section, and subjected to a steady shear rate of 0.5 dynes. μPIV measurements were made to map the flow over and around a biofilm tower structure which occluded approximately 66% of the channel width. Data were recorded around the structure at a series of two dimensional planes, which when stacked vertically show a two dimensional flow field as a function of tower height. Measurements and control volume analysis will be presented quantifying forces acting on these structures.

  5. Effect of biocides on biofilm bacteria from dental unit water lines.

    PubMed

    Liaqat, I; Sabri, A N

    2008-06-01

    Microbial biofilm formation in dental unit water lines (DUWL) is a phenomenon that has been recognized for nearly four decades. Water delivered by DUWL can harbor high numbers of bacteria, including opportunistic pathogens. Biofilms on tubing within DUWL may serve as a reservoir for these microorganisms and should therefore be controlled. In this study, the effects of eight biocides were monitored on DUWL biofilms individually and in combination by epifluorescence microscopy and total viable counts (TVC). The effects of sodium dodecyl sulphate (SDS), hydrogen peroxide (H2O2), sodium hypochlorite (NaOCl), phenol (Phe), Tween 20 (Tw 20), ethylenediaminetetraacetic acid (EDTA), chlorohexidine gluconate (CHX), and povidine iodine (PI) were tested on DUWL biofilms alone and in combination. PI was found to have negligible effects on biofilm removal either applied alone or in combined form with CHX. Applying all biocides simultaneously did not completely eliminate viable bacteria nor did they remove biofilm. Overall, when combined, the biocides performed better than singly applied products. The most effective biocides were NaOCl and Phe (both alone and in combination). PMID:18322732

  6. Mycobacterium avium Possesses Extracellular DNA that Contributes to Biofilm Formation, Structural Integrity, and Tolerance to Antibiotics

    PubMed Central

    Rose, Sasha J.; Babrak, Lmar M.; Bermudez, Luiz E.

    2015-01-01

    Mycobacterium avium subsp. hominissuis is an opportunistic pathogen that is associated with biofilm-related infections of the respiratory tract and is difficult to treat. In recent years, extracellular DNA (eDNA) has been found to be a major component of bacterial biofilms, including many pathogens involved in biofilm-associated infections. To date, eDNA has not been described as a component of mycobacterial biofilms. In this study, we identified and characterized eDNA in a high biofilm-producing strain of Mycobacterium avium subsp. hominissuis (MAH). In addition, we surveyed for presence of eDNA in various MAH strains and other nontuberculous mycobacteria. Biofilms of MAH A5 (high biofilm-producing strain) and MAH 104 (reference strain) were established at 22°C and 37°C on abiotic surfaces. Acellular biofilm matrix and supernatant from MAH A5 7 day-old biofilms both possess abundant eDNA, however very little eDNA was found in MAH 104 biofilms. A survey of MAH clinical isolates and other clinically relevant nontuberculous mycobacterial species revealed many species and strains that also produce eDNA. RAPD analysis demonstrated that eDNA resembles genomic DNA. Treatment with DNase I reduced the biomass of MAH A5 biofilms when added upon biofilm formation or to an already established biofilm both on abiotic surfaces and on top of human pharyngeal epithelial cells. Furthermore, co-treatment of an established biofilm with DNase 1 and either moxifloxacin or clarithromycin significantly increased the susceptibility of the bacteria within the biofilm to these clinically used antimicrobials. Collectively, our results describe an additional matrix component of mycobacterial biofilms and a potential new target to help treat biofilm-associated nontuberculous mycobacterial infections. PMID:26010725

  7. Genetic adaptation of Streptococcus mutans during biofilm formation on different types of surfaces

    PubMed Central

    2010-01-01

    Background Adhesion and successful colonization of bacteria onto solid surfaces play a key role in biofilm formation. The initial adhesion and the colonization of bacteria may differ between the various types of surfaces found in oral cavity. Therefore, it is conceivable that diverse biofilms are developed on those various surfaces. The aim of the study was to investigate the molecular modifications occurring during in vitro biofilm development of Streptococcus mutans UA159 on several different dental surfaces. Results Growth analysis of the immobilized bacterial populations generated on the different surfaces shows that the bacteria constructed a more confluent and thick biofilms on a hydroxyapatite surface compared to the other tested surfaces. Using DNA-microarray technology we identified the differentially expressed genes of S. mutans, reflecting the physiological state of biofilms formed on the different biomaterials tested. Eight selected genes were further analyzed by real time RT-PCR. To further determine the impact of the tested material surfaces on the physiology of the bacteria, we tested the secretion of AI-2 signal by S. mutans embedded on those biofilms. Comparative transcriptome analyses indicated on changes in the S. mutans genome in biofilms formed onto different types of surfaces and enabled us to identify genes most differentially expressed on those surfaces. In addition, the levels of autoinducer-2 in biofilms from the various tested surfaces were different. Conclusions Our results demonstrate that gene expression of S. mutans differs in biofilms formed on tested surfaces, which manifest the physiological state of bacteria influenced by the type of surface material they accumulate onto. Moreover, the stressful circumstances of adjustment to the surface may persist in the bacteria enhancing intercellular signaling and surface dependent biofilm formation. PMID:20167085

  8. Modeling cell-death patterning during biofilm formation

    NASA Astrophysics Data System (ADS)

    Ghosh, Pushpita; Ben-Jacob, Eshel; Levine, Herbert

    2013-12-01

    Self-organization by bacterial cells often leads to the formation of a highly complex spatially-structured biofilm. In such a bacterial biofilm, cells adhere to each other and are embedded in a self-produced extracellular matrix (ECM). Bacillus substilis bacteria utilize localized cell-death patterns which focuses mechanical forces to form wrinkled sheet-like structures in three dimensions. A most intriguing feature underlying this biofilm formation is that vertical buckling and ridge location is biased to occur in region of high cell-death. Here we present a spatially extended model to investigate the role of the bacterial secreted ECM during the biofilm formation and the self-organization of cell-death. Using this reaction-diffusion model we show that the interaction between the cell's motion and the ECM concentration gives rise to a self-trapping instability, leading to variety of cell-death patterns. The resultant spot patterns generated by our model are shown to be in semi-quantitative agreement with recent experimental observation.

  9. Characterization of Biofilm Formation in [Pasteurella] pneumotropica and [Actinobacillus] muris Isolates of Mouse Origin

    PubMed Central

    Sager, Martin; Benten, W. Peter M.; Engelhardt, Eva; Gougoula, Christina; Benga, Laurentiu

    2015-01-01

    [Pasteurella] pneumotropica biotypes Jawetz and Heyl and [Actinobacillus] muris are the most prevalent Pasteurellaceae species isolated from laboratory mouse. However, mechanisms contributing to their high prevalence such as the ability to form biofilms have not been studied yet. In the present investigation we analyze if these bacterial species can produce biofilms in vitro and investigate whether proteins, extracellular DNA and polysaccharides are involved in the biofilm formation and structure by inhibition and dispersal assays using proteinase K, DNase I and sodium periodate. Finally, the capacity of the biofilms to confer resistance to antibiotics is examined. We demonstrate that both [P.] pneumotropica biotypes but not [A.] muris are able to form robust biofilms in vitro, a phenotype which is widely spread among the field isolates. The biofilm inhibition and dispersal assays by proteinase and DNase lead to a strong inhibition in biofilm formation when added at the initiation of the biofilm formation and dispersed pre-formed [P.] pneumotropica biofilms, revealing thus that proteins and extracellular DNA are essential in biofilm formation and structure. Sodium periodate inhibited the bacterial growth when added at the beginning of the biofilm formation assay, making difficult the assessment of the role of β-1,6-linked polysaccharides in the biofilm formation, and had a biofilm stimulating effect when added on pre-established mature biofilms of [P.] pneumotropica biotype Heyl and a majority of [P.] pneumotropica biotype Jawetz strains, suggesting that the presence of β-1,6-linked polysaccharides on the bacterial surface might attenuate the biofilm production. Conversely, no effect or a decrease in the biofilm quantity was observed by biofilm dispersal using sodium periodate on further biotype Jawetz isolates, suggesting that polysaccharides might be incorporated in the biofilm structure. We additionally show that [P.] pneumotropica cells enclosed in biofilms were less sensitive to treatment with amoxicillin and enrofloxacin than planktonic bacteria. Taken together, these findings provide a first step in understanding of the biofilm mechanisms in [P.] pneumotropica, which might contribute to elucidation of colonization and pathogenesis mechanisms for these obligate inhabitants of the mouse mucosa. PMID:26430880

  10. Photoinactivation of bacteria attached to glass and acrylic surfaces by 405 nm light: potential application for biofilm decontamination.

    PubMed

    McKenzie, Karen; Maclean, Michelle; Timoshkin, Igor V; Endarko, Endarko; MacGregor, Scott J; Anderson, John G

    2013-01-01

    Attachment of bacteria to surfaces and subsequent biofilm formation remains a major cause of cross-contamination capable of inducing both food-related illness and nosocomial infections. Resistance to many current disinfection technologies means facilitating their removal is often difficult. The aim of this study was to investigate the efficacy of 405 nm light for inactivation of bacterial attached as biofilms to glass and acrylic. Escherichia coli biofilms (10(3)-10(8) CFU mL(-1)) were generated on glass and acrylic surfaces and exposed for increasing times to 405 nm light (5-60 min) at ca 140 mW cm(-2). Successful inactivation of biofilms has been demonstrated, with results highlighting complete/near-complete inactivation (up to 5 log10 reduction on acrylic and 7 log10 on glass). Results also highlight that inactivation of bacterial biofilms could be achieved whether the biofilm was on the upper "directly exposed" surface or "indirectly exposed" underside surface. Statistically significant inactivation was also shown with a range of other microorganisms associated with biofilm formation (Staphylococcus aureus, Pseudomonas aeruginosa and Listeria monocytogenes). Results from this study have demonstrated significant inactivation of bacteria ranging from monolayers to densely populated biofilms using 405 nm light, highlighting that with further development this technology may have potential applications for biofilm decontamination in food and clinical settings. PMID:23550978

  11. Experimental and Computational Investigation of Biofilm Formation by Rhodopseudomonas palustris Growth under Two Metabolic Modes

    PubMed Central

    Kernan, Chase; Chow, Philicia P.; Christianson, Rebecca J.; Huang, Jean

    2015-01-01

    We examined biofilms formed by the metabolically versatile bacterium Rhodopseudomonas palustris grown via different metabolic modes. R. palustris was grown in flow cell chambers with identical medium conditions either in the presence or absence of light and oxygen. In the absence of oxygen and the presence of light, R. palustris grew and formed biofilms photoheterotrophically, and in the presence of oxygen and the absence of light, R. palustris grew and formed biofilms heterotrophically. We used confocal laser scanning microscopy and image analysis software to quantitatively analyze and compare R. palustris biofilm formation over time in these two metabolic modes. We describe quantifiable differences in structure between the biofilms formed by the bacterium grown heterotrophically and those grown photoheterotrophically. We developed a computational model to explore ways in which biotic and abiotic parameters could drive the observed biofilm architectures, as well as a random-forest machine-learning algorithm based on structural differences that was able to identify growth conditions from the confocal imaging of the biofilms with 87% accuracy. Insight into the structure of phototrophic biofilms and conditions that influence biofilm formation is relevant for understanding the generation of biofilm structures with different properties, and for optimizing applications with phototrophic bacteria growing in the biofilm state. PMID:26087200

  12. Alternative modes of biofilm formation by plant-associated Bacillus cereus

    PubMed Central

    Gao, Tantan; Foulston, Lucy; Chai, Yunrong; Wang, Qi; Losick, Richard

    2015-01-01

    The ability to form multicellular communities known as biofilms is a widespread adaptive behavior of bacteria. Members of the Bacillus group of bacteria have been found to form biofilms on plant roots, where they protect against pathogens and promote growth. In the case of the model bacterium Bacillus subtilis the genetic pathway controlling biofilm formation and the production of an extracellular matrix is relatively well understood. However, it is unclear whether other members of this genus utilize similar mechanisms. We determined that a plant-associated strain of Bacillus cereus (905) can form biofilms by two seemingly independent pathways. In one mode involving the formation of floating biofilms (pellicles) B. cereus 905 appears to rely on orthologs of many of the genes known to be important for B. subtilis biofilm formation. We report that B. cereus 905 also forms submerged, surface-associated biofilms and in a manner that resembles biofilm formation by the pathogen Staphylococcus aureus. This alternative mode, which does not rely on B. subtilis-like genes for pellicle formation, takes place under conditions of glucose fermentation and depends on a drop in the pH of the medium. PMID:25828975

  13. An individual-based model for biofilm formation at liquid surfaces

    NASA Astrophysics Data System (ADS)

    Ardré, Maxime; Henry, Hervé; Douarche, Carine; Plapp, Mathis

    2015-12-01

    The bacterium Bacillus subtilis frequently forms biofilms at the interface between the culture medium and the air. We present a mathematical model that couples a description of bacteria as individual discrete objects to the standard advection-diffusion equations for the environment. The model takes into account two different bacterial phenotypes. In the motile state, bacteria swim and perform a run-and-tumble motion that is biased toward regions of high oxygen concentration (aerotaxis). In the matrix-producer state they excrete extracellular polymers, which allows them to connect to other bacteria and to form a biofilm. Bacteria are also advected by the fluid, and can trigger bioconvection. Numerical simulations of the model reproduce all the stages of biofilm formation observed in laboratory experiments. Finally, we study the influence of various model parameters on the dynamics and morphology of biofilms.

  14. An individual-based model for biofilm formation at liquid surfaces.

    PubMed

    Ardré, Maxime; Henry, Hervé; Douarche, Carine; Plapp, Mathis

    2015-01-01

    The bacterium Bacillus subtilis frequently forms biofilms at the interface between the culture medium and the air. We present a mathematical model that couples a description of bacteria as individual discrete objects to the standard advection-diffusion equations for the environment. The model takes into account two different bacterial phenotypes. In the motile state, bacteria swim and perform a run-and-tumble motion that is biased toward regions of high oxygen concentration (aerotaxis). In the matrix-producer state they excrete extracellular polymers, which allows them to connect to other bacteria and to form a biofilm. Bacteria are also advected by the fluid, and can trigger bioconvection. Numerical simulations of the model reproduce all the stages of biofilm formation observed in laboratory experiments. Finally, we study the influence of various model parameters on the dynamics and morphology of biofilms. PMID:26656539

  15. Influence of nanohydroxyapatite surface properties on Staphylococcus epidermidis biofilm formation.

    PubMed

    Barros, J; Grenho, L; Manuel, C M; Ferreira, C; Melo, L; Nunes, O C; Monteiro, F J; Ferraz, M P

    2014-05-01

    Nanohydroxyapatite (nanoHA), due to its chemical properties, has appeared as an exceptionally promising bioceramic to be used as bone regeneration material. Staphylococcus epidermidis have emerged as major nosocomial pathogens associated with infections of implanted medical devices. In this work, the purpose was to study the influence of the nanoHA surface characteristics on S. epidermidis RP62A biofilm formation. Therefore, two different initial inoculum concentrations (Ci) were used in order to check if these would affect the biofilm formed on the nanoHA surfaces. Biofilm formation was followed by the enumeration of cultivable cells and by scanning electron microscopy. Surface topography, contact angle, total surface area and porosimetry of the biomaterials were studied and correlated with the biofilm data. The surface of nanoHA sintered at 830 (nanoHA830) showed to be more resistant to S. epidermidis attachment and accumulation than that of nanoHA sintered at 1000 (nanoHA1000). The biofilm formed on nanoHA830 presented differences in terms of structure, surface coverage and EPS production when compared to the one formed on nanoHA1000 surface. It was observed that topography and surface area of nanoHA surfaces had influence on the bacterial attachment and accumulation. Ci influenced bacteria attachment and accumulation on nanoHA surfaces over time. The choice of the initial inoculum concentration was relevant proving to have an effect on the extent of adherence thus being a critical point for human health if these materials are used in implantable devices. This study showed that the initial inoculum concentration and surface material properties determine the rate of microbial attachment to substrata and consequently are related to biofilm-associated infections in biomaterials. PMID:24122400

  16. Application of alkaliphilic biofilm-forming bacteria to improve compressive strength of cement-sand mortar.

    PubMed

    Park, Sung-Jin; Chun, Woo-Young; Kim, Wha-Jung; Ghim, Sa-Youl

    2012-03-01

    The application of microorganisms in the field of construction material is rapidly increasing worldwide; however, almost all studies that were investigated were bacterial sources with mineral-producing activity and not with organic substances. The difference in the efficiency of using bacteria as an organic agent is that it could improve the durability of cement material. This study aimed to assess the use of biofilm-forming microorganisms as binding agents to increase the compressive strength of cement-sand material. We isolated 13 alkaliphilic biofilmforming bacteria (ABB) from a cement tetrapod block in the West Sea, Korea. Using 16S RNA sequence analysis, the ABB were partially identified as Bacillus algicola KNUC501 and Exiguobacterium marinum KNUC513. KNUC513 was selected for further study following analysis of pH and biofilm formation. Cement-sand mortar cubes containing KNUC513 exhibited greater compressive strength than mineral-forming bacteria (Sporosarcina pasteurii and Arthrobacter crystallopoietes KNUC403). To determine the biofilm effect, Dnase I was used to suppress the biofilm formation of KNUC513. Field emission scanning electron microscopy image revealed the direct involvement of organic-inorganic substance in cement-sand mortar. PMID:22450795

  17. Involvement of Stress-Related Genes polB and PA14_46880 in Biofilm Formation of Pseudomonas aeruginosa

    PubMed Central

    Alshalchi, Sahar A.

    2014-01-01

    Chronic infections of Pseudomonas aeruginosa are generally established through production of biofilm. During biofilm formation, production of an extracellular matrix and establishment of a distinct bacterial phenotype make these infections difficult to eradicate. However, biofilm studies have been hampered by the fact that most assays utilize nonliving surfaces as biofilm attachment substrates. In an attempt to better understand the mechanisms behind P. aeruginosa biofilm formation, we performed a genetic screen to identify novel factors involved in biofilm formation on biotic and abiotic surfaces. We found that deletion of genes polB and PA14_46880 reduced biofilm formation significantly compared to that in the wild-type strain PA14 in an abiotic biofilm system. In a biotic biofilm model, wherein biofilms form on cultured airway cells, the ΔpolB and ΔPA14_46880 strains showed increased cytotoxic killing of the airway cells independent of the total number of bacteria bound. Notably, deletion mutant strains were more resistant to ciprofloxacin treatment. This phenotype was linked to decreased expression of algR, an alginate transcriptional regulatory gene, under ciprofloxacin pressure. Moreover, we found that pyocyanin production was increased in planktonic cells of mutant strains. These results indicate that inactivation of polB and PA14_46880 may inhibit transition of P. aeruginosa from a more acute infection lifestyle to the biofilm phenotype. Future investigation of these genes may lead to a better understanding of P. aeruginosa biofilm formation and chronic biofilm infections. PMID:25156741

  18. Tissue Plasminogen Activator Coating on Implant Surfaces Reduces Staphylococcus aureus Biofilm Formation.

    PubMed

    Kwiecinski, Jakub; Na, Manli; Jarneborn, Anders; Jacobsson, Gunnar; Peetermans, Marijke; Verhamme, Peter; Jin, Tao

    2015-01-01

    Staphylococcus aureus biofilm infections of indwelling medical devices are a major medical challenge because of their high prevalence and antibiotic resistance. As fibrin plays an important role in S. aureus biofilm formation, we hypothesize that coating of the implant surface with fibrinolytic agents can be used as a new method of antibiofilm prophylaxis. The effect of tissue plasminogen activator (tPA) coating on S. aureus biofilm formation was tested with in vitro microplate biofilm assays and an in vivo mouse model of biofilm infection. tPA coating efficiently inhibited biofilm formation by various S. aureus strains. The effect was dependent on plasminogen activation by tPA, leading to subsequent local fibrin cleavage. A tPA coating on implant surfaces prevented both early adhesion and later biomass accumulation. Furthermore, tPA coating increased the susceptibility of biofilm infections to antibiotics. In vivo, significantly fewer bacteria were detected on the surfaces of implants coated with tPA than on control implants from mice treated with cloxacillin. Fibrinolytic coatings (e.g., with tPA) reduce S. aureus biofilm formation both in vitro and in vivo, suggesting a novel way to prevent bacterial biofilm infections of indwelling medical devices. PMID:26519394

  19. Enhanced biofilm formation and multi-host transmission evolve from divergent genetic backgrounds in Campylobacter jejuni.

    PubMed

    Pascoe, Ben; Mric, Guillaume; Murray, Susan; Yahara, Koji; Mageiros, Leonardos; Bowen, Ryan; Jones, Nathan H; Jeeves, Rose E; Lappin-Scott, Hilary M; Asakura, Hiroshi; Sheppard, Samuel K

    2015-11-01

    Multicellular biofilms are an ancient bacterial adaptation that offers a protective environment for survival in hostile habitats. In microaerophilic organisms such as Campylobacter, biofilms play a key role in transmission to humans as the bacteria are exposed to atmospheric oxygen concentrations when leaving the reservoir host gut. Genetic determinants of biofilm formation differ between species, but little is known about how strains of the same species achieve the biofilm phenotype with different genetic backgrounds. Our approach combines genome-wide association studies with traditional microbiology techniques to investigate the genetic basis of biofilm formation in 102?Campylobacter jejuni isolates. We quantified biofilm formation among the isolates and identified hotspots of genetic variation in homologous sequences that correspond to variation in biofilm phenotypes. Thirteen genes demonstrated a statistically robust association including those involved in adhesion, motility, glycosylation, capsule production and oxidative stress. The genes associated with biofilm formation were different in the host generalist ST-21 and ST-45 clonal complexes, which are frequently isolated from multiple host species and clinical samples. This suggests the evolution of enhanced biofilm from different genetic backgrounds and a possible role in colonization of multiple hosts and transmission to humans. PMID:26373338

  20. Dynamics of Aerial Tower Formation in Bacillus subtilis Biofilms

    NASA Astrophysics Data System (ADS)

    Sinha, Naveen; Seminara, Agnese; Wilking, James; Brenner, Michael; Weitz, Dave

    2012-02-01

    Biofilms are highly-organized colonies of bacteria that form on surfaces. These colonies form sophisticated structures which make them robust and difficult to remove from environments such as catheters, where they pose serious infection problems. Previous work has shown that sub-mm sized aerial towers form on the surface of Bacillus subtilis colony biofilms. Spore-formation is located preferentially at the tops of these towers, known as fruiting bodies, which aid in the dispersal and propagation of the colony to new sites. The formation of towers is strongly affected by the quorum-sensing molecule surfactin and the cannibalism pathway of the bacteria. In the present work, we use confocal fluorescence microscopy to study the development of individual fruiting bodies, allowing us to visualize the time-dependent spatial distribution of matrix-forming and sporulating bacteria within the towers. With this information, we investigate the physical mechanisms, such as surface tension and polymer concentration gradients, that drive the formation of these structures.

  1. Derivatives of the mouse cathelicidin-related antimicrobial peptide (CRAMP) inhibit fungal and bacterial biofilm formation.

    PubMed

    De Brucker, Katrijn; Delattin, Nicolas; Robijns, Stijn; Steenackers, Hans; Verstraeten, Natalie; Landuyt, Bart; Luyten, Walter; Schoofs, Liliane; Dovgan, Barbara; Frhlich, Mirjam; Michiels, Jan; Vanderleyden, Jos; Cammue, Bruno P A; Thevissen, Karin

    2014-09-01

    We identified a 26-amino-acid truncated form of the 34-amino-acid cathelicidin-related antimicrobial peptide (CRAMP) in the islets of Langerhans of the murine pancreas. This peptide, P318, shares 67% identity with the LL-37 human antimicrobial peptide. As LL-37 displays antimicrobial and antibiofilm activity, we tested antifungal and antibiofilm activity of P318 against the fungal pathogen Candida albicans. P318 shows biofilm-specific activity as it inhibits C. albicans biofilm formation at 0.15 ?M without affecting planktonic survival at that concentration. Next, we tested the C. albicans biofilm-inhibitory activity of a series of truncated and alanine-substituted derivatives of P318. Based on the biofilm-inhibitory activity of these derivatives and the length of the peptides, we decided to synthesize the shortened alanine-substituted peptide at position 10 (AS10; KLKKIAQKIKNFFQKLVP). AS10 inhibited C. albicans biofilm formation at 0.22 ?M and acted synergistically with amphotericin B and caspofungin against mature biofilms. AS10 also inhibited biofilm formation of different bacteria as well as of fungi and bacteria in a mixed biofilm. In addition, AS10 does not affect the viability or functionality of different cell types involved in osseointegration of an implant, pointing to the potential of AS10 for further development as a lead peptide to coat implants. PMID:24982087

  2. Derivatives of the Mouse Cathelicidin-Related Antimicrobial Peptide (CRAMP) Inhibit Fungal and Bacterial Biofilm Formation

    PubMed Central

    De Brucker, Katrijn; Delattin, Nicolas; Robijns, Stijn; Steenackers, Hans; Verstraeten, Natalie; Landuyt, Bart; Luyten, Walter; Schoofs, Liliane; Dovgan, Barbara; Fröhlich, Mirjam; Michiels, Jan; Vanderleyden, Jos; Thevissen, Karin

    2014-01-01

    We identified a 26-amino-acid truncated form of the 34-amino-acid cathelicidin-related antimicrobial peptide (CRAMP) in the islets of Langerhans of the murine pancreas. This peptide, P318, shares 67% identity with the LL-37 human antimicrobial peptide. As LL-37 displays antimicrobial and antibiofilm activity, we tested antifungal and antibiofilm activity of P318 against the fungal pathogen Candida albicans. P318 shows biofilm-specific activity as it inhibits C. albicans biofilm formation at 0.15 μM without affecting planktonic survival at that concentration. Next, we tested the C. albicans biofilm-inhibitory activity of a series of truncated and alanine-substituted derivatives of P318. Based on the biofilm-inhibitory activity of these derivatives and the length of the peptides, we decided to synthesize the shortened alanine-substituted peptide at position 10 (AS10; KLKKIAQKIKNFFQKLVP). AS10 inhibited C. albicans biofilm formation at 0.22 μM and acted synergistically with amphotericin B and caspofungin against mature biofilms. AS10 also inhibited biofilm formation of different bacteria as well as of fungi and bacteria in a mixed biofilm. In addition, AS10 does not affect the viability or functionality of different cell types involved in osseointegration of an implant, pointing to the potential of AS10 for further development as a lead peptide to coat implants. PMID:24982087

  3. Naturally Ocurring Polyphosphate-accumulating Bacteria in Benthic Biofilms

    NASA Astrophysics Data System (ADS)

    Locke, N. A.; Saia, S. M.; Walter, M. T.; Carrick, H. J.; Buda, A. R.; Regan, J. M.

    2014-12-01

    Polyphosphate accumulating organisms (PAOs), known to store excess phosphorus (P) as polyphosphate (poly-P), influence P transport in the environment. Enhanced biological phosphorus removal (EBPR) from wastewater has long served as a basis to study bacterial PAOs, yet little research has genetically identified similar organisms in natural settings. Aerobic/anaerobic cycles, used to select for PAOs in EBPR, can result from changing environmental conditions such as night/day cycles for benthic biofilms. Benthic biofilms from eight Pennsylvanian streams were studied for naturally-occurring bacterial PAOs similar to those typically found in EBPR systems. PAOs were confirmed in the benthic biofilms by a characteristic yellow fluorescent emission from DAPI staining. Cells containing yellow fluorescence were separated from the rest of the sample using a flow cytometer, resulting in a physically enriched culture of PAOs from the benthic biofilms. Amplicon-based metagenomic sequencing will reveal the phylogeny of bacteria responsible for poly-P accumulation in these benthic biofilms. Sequencing data will be used to develop fluorescent in-situ hybridization (FISH) probes, and hybridizations will be performed on DAPI-stained cells to confirm poly-P accumulation by targeted phylotypes. Identifying PAOs in natural settings is a critical step towards studying environments that support high concentrations of PAOs, serving as significant factors in the P cycle. PAOs can then be connected to P transport models to help understand and mitigate P pollution in agricultural watersheds.

  4. Quorum sensing and biofilm formation investigated using laser-trapped bacterial arrays

    NASA Astrophysics Data System (ADS)

    Gordon, Vernita; Butler, John; Smalyukh, Ivan; Parsek, Matthew; Wong, Gerard

    2008-03-01

    Studies of individual, free-swimming (planktonic) bacteria have yielded much information about their genetic and phenotypic characteristics and about ``quorum sensing,'' the autoinducing process by which bacteria detect high concentrations of other bacteria. However, in most environments the majority of bacteria are not in the planktonic form but are rather in biofilms, which are highly-structured, dynamic communities of multiple bacteria that adhere to a surface and to each other using an extracellular polysaccharide matrix. Bacteria in biofilms are phenotypically very different from their genetically-identical planktonic counterparts. Among other characteristics, they are much more antibiotic-resistant and virulent. Such biofilms form persistent infections on medical implants and in the lungs of cystic fibrosis patients, where Pseudomonas aeruginosa biofilms are the leading cause of lung damage and, ultimately, death. To understand the importance of different extracellular materials, motility mechanisms, and quorum sensing for biofilm formation and stability, we use single-gene knockout mutants and an infrared laser trap to create a bacterial aggregate that serves as a model biofilm and allows us to measure the importance of these factors as a function of trapping time, surface, and nutritional environment.

  5. Mechanistic lessons learned from studies of planktonic bacteria with metallic nanomaterials: implications for interactions between nanomaterials and biofilm bacteria

    PubMed Central

    Saleh, Navid B.; Chambers, Bryant; Aich, Nirupam; Plazas-Tuttle, Jaime; Phung-Ngoc, Hanh N.; Kirisits, Mary Jo

    2015-01-01

    Metal and metal-oxide nanoparticles (NPs) are used in numerous applications and have high likelihood of entering engineered and natural environmental systems. Careful assessment of the interaction of these NPs with bacteria, particularly biofilm bacteria, is necessary. This perspective discusses mechanisms of NP interaction with bacteria and identifies challenges in understanding NP–biofilm interaction, considering fundamental material attributes and inherent complexities of biofilm structure. The current literature is reviewed, both for planktonic bacteria and biofilms; future challenges and complexities are identified, both in light of the literature and a dataset on the toxicity of silver NPs toward planktonic and biofilm bacteria. This perspective aims to highlight the complexities in such studies and emphasizes the need for systematic evaluation of NP–biofilm interaction. PMID:26236285

  6. Detection of Quorum Sensing Molecules and Biofilm Formation in Ralstonia solanacearum.

    PubMed

    Kumar, J Shiva; Umesha, S; Prasad, K Shiva; Niranjana, P

    2016-03-01

    Many bacteria use small diffusible signaling molecules to communicate each other termed as quorum sensing (QS). Most Gram-negative bacteria use acyl homoserine lactone (AHL) as QS signal molecules. Using these signaling molecules, bacteria are able to express specific genes in response to population density. This work aimed to detect the production of QS signal molecules and biofilm formation in Ralstonia solanacearum isolated from various diseased tomato plants with symptoms of bacterial wilt. A total of 30 R. solanacearum strains were investigated for the production of QS signal molecules using Chromobacterium violaceum CV026 and Agrobacterium tumefaciens NT1 (pZLR4) biosensor systems. All 30 bacterial isolates from various bacterial wilt-affected tomato plants produced AHL molecules that induced the biosensor. The microtiter plate assay demonstrated that of the 30 bacterial isolates, 60 % formed biofilm, among which four isolates exhibited a higher degree of biofilm formation. The biofilm-inducing factor was purified from these four culture supernatants. The structure of the responsible molecule was solved using nuclear magnetic resonance and mass spectroscopy and was determined to be 2-hydroxy-4-((methylamino)(phenyl)methyl) cyclopentanone (HMCP), which was confirmed by chemical synthesis and NMR. The Confocal laser scanning microscopic analysis showed well-developed biofilm architecture of bacteria when treated with HMCP. The knowledge we obtained from this study will be useful for further researcher on the role of HMCP molecule in biofilm formation. PMID:26620535

  7. Biofilm formation and surface exploration behavior of P. aeruginosa

    NASA Astrophysics Data System (ADS)

    Beckerman, Bernard; Zhao, Kun; Wong, Gerard; Luijten, Erik

    2013-03-01

    Despite extensive studies, the early stages of biofilm formation are not fully understood. Recent work on the opportunistic pathogen Pseudomonas aeruginosa has shown that these bacteria deposit the exopolysaccharide Psl as they move across a surface, which in turn attracts repeat visits of bacteria to the sites of deposition. Using a massively parallel cell-tracking algorithm combined with fluorescent Psl staining and computer simulations, we show that this behavior results in a surface visit distribution that can be approximated by a power law. The steepness of this Zipf's Law is a measure of the hierarchical nature of bacterial surface visits, and is (among other parameters) a function of both Psl secretion rate and sensitivity of the bacteria to Psl. We characterize the bacterial distributions using various computational techniques to quantitatively analyze the effect of Psl on microcolony organization and to identify the key stages of microcolony growth. This work was supported by the National Institutes of Health and the National Science Foundation.

  8. Density of founder cells affects spatial pattern formation and cooperation in Bacillus subtilis biofilms

    PubMed Central

    van Gestel, Jordi; Weissing, Franz J; Kuipers, Oscar P; Kovács, Ákos T

    2014-01-01

    In nature, most bacteria live in surface-attached sedentary communities known as biofilms. Biofilms are often studied with respect to bacterial interactions. Many cells inhabiting biofilms are assumed to express ‘cooperative traits', like the secretion of extracellular polysaccharides (EPS). These traits can enhance biofilm-related properties, such as stress resilience or colony expansion, while being costly to the cells that express them. In well-mixed populations cooperation is difficult to achieve, because non-cooperative individuals can reap the benefits of cooperation without having to pay the costs. The physical process of biofilm growth can, however, result in the spatial segregation of cooperative from non-cooperative individuals. This segregation can prevent non-cooperative cells from exploiting cooperative neighbors. Here we examine the interaction between spatial pattern formation and cooperation in Bacillus subtilis biofilms. We show, experimentally and by mathematical modeling, that the density of cells at the onset of biofilm growth affects pattern formation during biofilm growth. At low initial cell densities, co-cultured strains strongly segregate in space, whereas spatial segregation does not occur at high initial cell densities. As a consequence, EPS-producing cells have a competitive advantage over non-cooperative mutants when biofilms are initiated at a low density of founder cells, whereas EPS-deficient cells have an advantage at high cell densities. These results underline the importance of spatial pattern formation for competition among bacterial strains and the evolution of microbial cooperation. PMID:24694715

  9. Biofilm formation by Chlorella vulgaris is affected by light quality.

    PubMed

    Hultberg, Malin; Asp, Håkan; Marttila, Salla; Bergstrand, Karl-Johan; Gustafsson, Susanne

    2014-11-01

    Formation of biofilm on surfaces is a common feature in aquatic environments. Major groups of inhabitants in conditions where light is present are photoautotrophic microorganisms, such as cyanobacteria and microalgae. This study examined the effect of light quality on growth and biofilm formation of the microalgal species Chlorella vulgaris. Dense biofilm formation and aggregated growth of cells were observed in treatments exposed to blue, purple and white light. Less dense biofilm formation and solitary growth of cells were observed in treatments exposed to red, yellow or green light. Microalgal biofilms are of high importance in many respects, not least from an economic perspective. One example is the intense efforts undertaken to control biofilm formation on technical surfaces such as ship hulls. The present study suggests that light quality plays a role in biofilm formation and that blue-light receptors may be involved. PMID:24985199

  10. The Natural Antimicrobial Carvacrol Inhibits Quorum Sensing in Chromobacterium violaceum and Reduces Bacterial Biofilm Formation at Sub-Lethal Concentrations

    PubMed Central

    Burt, Sara A.; Ojo-Fakunle, Victoria T. A.; Woertman, Jenifer; Veldhuizen, Edwin J. A.

    2014-01-01

    The formation of biofilm by bacteria confers resistance to biocides and presents problems in medical and veterinary clinical settings. Here we report the effect of carvacrol, one of the major antimicrobial components of oregano oil, on the formation of biofilms and its activity on existing biofilms. Assays were carried out in polystyrene microplates to observe (a) the effect of 0–0.8 mM carvacrol on the formation of biofilms by selected bacterial pathogens over 24 h and (b) the effect of 0–8 mM carvacrol on the stability of pre-formed biofilms. Carvacrol was able to inhibit the formation of biofilms of Chromobacterium violaceum ATCC 12472, Salmonella enterica subsp. Typhimurium DT104, and Staphylococcus aureus 0074, while it showed no effect on formation of Pseudomonas aeruginosa (field isolate) biofilms. This inhibitory effect of carvacrol was observed at sub-lethal concentrations (<0.5 mM) where no effect was seen on total bacterial numbers, indicating that carvacrol's bactericidal effect was not causing the observed inhibition of biofilm formation. In contrast, carvacrol had (up to 8 mM) very little or no activity against existing biofilms of the bacteria described, showing that formation of the biofilm also confers protection against this compound. Since quorum sensing is an essential part of biofilm formation, the effect of carvacrol on quorum sensing of C. violaceum was also studied. Sub-MIC concentrations of carvacrol reduced expression of cviI (a gene coding for the N-acyl-L-homoserine lactone synthase), production of violacein (pigmentation) and chitinase activity (both regulated by quorum sensing) at concentrations coinciding with carvacrol's inhibiting effect on biofilm formation. These results indicate that carvacrol's activity in inhibition of biofilm formation may be related to the disruption of quorum sensing. PMID:24691035

  11. Genome-Wide Mutagenesis of Xanthomonas axonopodis pv. citri Reveals Novel Genetic Determinants and Regulation Mechanisms of Biofilm Formation

    PubMed Central

    Li, Jinyun; Wang, Nian

    2011-01-01

    Xanthomonas axonopodis pv. citri (Xac) causes citrus canker disease, a major threat to citrus production worldwide. Accumulating evidence suggests that the formation of biofilms on citrus leaves plays an important role in the epiphytic survival of this pathogen prior to the development of canker disease. However, the process of Xac biofilm formation is poorly understood. Here, we report a genome-scale study of Xac biofilm formation in which we identified 92 genes, including 33 novel genes involved in biofilm formation and 7 previously characterized genes, colR, fhaB, fliC, galU, gumD, wxacO, and rbfC, known to be important for Xac biofilm formation. In addition, 52 other genes with defined or putative functions in biofilm formation were identified, even though they had not previously reported been to be associated with biofilm formation. The 92 genes were isolated from 292 biofilm-defective mutants following a screen of a transposon insertion library containing 22,000 Xac strain 306 mutants. Further analyses indicated that 16 of the novel genes are involved in the production of extracellular polysaccharide (EPS) and/or lipopolysaccharide (LPS), 7 genes are involved in signaling and regulatory pathways, and 5 genes have unknown roles in biofilm formation. Furthermore, two novel genes, XAC0482, encoding a haloacid dehalogenase-like phosphatase, and XAC0494 (designated as rbfS), encoding a two-component sensor protein, were confirmed to be biofilm-related genes through complementation assays. Our data demonstrate that the formation of mature biofilm requires EPS, LPS, both flagellum-dependent and flagellum-independent cell motility, secreted proteins and extracellular DNA. Additionally, multiple signaling pathways are involved in Xac biofilm formation. This work is the first report on a genome-wide scale of the genetic processes of biofilm formation in plant pathogenic bacteria. The report provides significant new information about the genetic determinants and regulatory mechanism of biofilm formation. PMID:21750733

  12. Screening of lactic acid bacteria that can form mixed-species biofilm with Saccharomyces cerevisiae.

    PubMed

    Furukawa, Soichi; Isomae, Ryosuke; Tsuchiya, Noriko; Hirayama, Satoru; Yamagishi, Asuka; Kobayashi, Miho; Suzuki, Chise; Ogihara, Hirokazu; Morinaga, Yasushi

    2015-01-01

    The abilities of lactic acid bacteria (LAB) to form mixed-species biofilm with Saccharomyces cerevisiae in a static co-culture were investigated out of 168 LAB stock cultures, and two Lactobacillus plantarum strains (D71 and E31) and one Leuconostoc mesenteroides strain K01 were found to form mixed-species biofilm with S. cerevisiae BY4741. SEM observation showed that there was no significant difference in morphological properties among these three mixed-species biofilms and they resembled that formed by S. cerevisiae with L. plantarum ML11-11 previously isolated from a brewing sample of Fukuyama pot vinegar. The co-aggregation assays showed that L. plantarum D71 and L. plantarum E31 could co-aggregate with S. cerevisiae similarly to L. plantarum ML11-11, while L. mesenteroides K01 had no ability to co-aggregate with yeast. The above results indicate that aggregation followed by direct cell-to-cell contact is required for mixed-species biofilm formation between these L. plantarum strains and S. cerevisiae, though some different mechanism may be involved in biofilm formation between L. mesenteroides strain and S. cerevisiae. PMID:25514879

  13. Effect of serogroup, surface material and disinfectant on biofilm formation by avian pathogenic Escherichia coli.

    PubMed

    Oosterik, Leon H; Tuntufye, Huruma N; Butaye, Patrick; Goddeeris, Bruno M

    2014-12-01

    Avian pathogenic Escherichia coli (APEC) are responsible for significant economic losses in the poultry industry and are difficult to eradicate. Biofilm formation by APEC has the potential to reduce the efficacy of cleaning and disinfection. In this study, biofilm formation on materials used in poultry facilities by APEC strains from laying hens was determined. APEC strains were analysed for an association between biofilm forming capacity and O serogroup. The abilities of two routinely used disinfectants, hydrogen peroxide (H2O2) and a quaternary ammonium compound (QAC), to kill adherent cells of two strong APEC biofilm producers (05/503 and 04/40) and a non-biofilm producer (05/293) on polystyrene (PS) and polyvinylchloride (PVC) surfaces were tested. Most APEC strains were moderate (PS) or strong biofilm producers (polypropylene, PP, and PVC). Strains in serogroup O2 more often belonged to the moderate (PS) or strong (PP and PVC) biofilm producers than to other groups, while most O78 strains were weak biofilm producers. O78 strains were stronger biofilm producers on stainless steel than on PP and PVC, while O2 strains were stronger biofilm producers on PP and PVC. A concentration of 1% H2O2 killed all adherent bacteria of strains 05/503 and 04/40 on PP and PVC, while 0.5% H2O2 killed all adherent bacteria of strain 05/293. QAC at a concentration of 0.01% killed all adherent cells of strains 05/503, 04/40 and 05/293 under equal conditions. In conclusion, biofilm formation by APEC was affected by serogroup and surface material, and inactivation of APEC was dependent on the disinfectant and surface material. PMID:25455385

  14. Biofilm Formation Protects Escherichia coli against Killing by Caenorhabditis elegans and Myxococcus xanthus

    PubMed Central

    DePas, William H.; Syed, Adnan K.; Sifuentes, Margarita; Lee, John S.; Warshaw, David; Saggar, Vinay; Csankovszki, Györgyi; Boles, Blaise R.

    2014-01-01

    Enteric bacteria, such as Escherichia coli, are exposed to a variety of stresses in the nonhost environment. The development of biofilms provides E. coli with resistance to environmental insults, such as desiccation and bleach. We found that biofilm formation, specifically production of the matrix components curli and cellulose, protected E. coli against killing by the soil-dwelling nematode Caenorhabditis elegans and the predatory bacterium Myxococcus xanthus. Additionally, matrix-encased bacteria at the air-biofilm interface exhibited ∼40-fold-increased survival after C. elegans and M. xanthus killing compared to the non-matrix-encased cells that populate the interior of the biofilm. To determine if nonhost Enterobacteriaceae reservoirs supported biofilm formation, we grew E. coli on media composed of pig dung or commonly contaminated foods, such as beef, chicken, and spinach. Each of these medium types provided a nutritional environment that supported matrix production and biofilm formation. Altogether, we showed that common, nonhost reservoirs of E. coli supported the formation of biofilms that subsequently protected E. coli against predation. PMID:25192998

  15. Biofilm formation protects Escherichia coli against killing by Caenorhabditis elegans and Myxococcus xanthus.

    PubMed

    DePas, William H; Syed, Adnan K; Sifuentes, Margarita; Lee, John S; Warshaw, David; Saggar, Vinay; Csankovszki, Gyrgyi; Boles, Blaise R; Chapman, Matthew R

    2014-11-01

    Enteric bacteria, such as Escherichia coli, are exposed to a variety of stresses in the nonhost environment. The development of biofilms provides E. coli with resistance to environmental insults, such as desiccation and bleach. We found that biofilm formation, specifically production of the matrix components curli and cellulose, protected E. coli against killing by the soil-dwelling nematode Caenorhabditis elegans and the predatory bacterium Myxococcus xanthus. Additionally, matrix-encased bacteria at the air-biofilm interface exhibited ?40-fold-increased survival after C. elegans and M. xanthus killing compared to the non-matrix-encased cells that populate the interior of the biofilm. To determine if nonhost Enterobacteriaceae reservoirs supported biofilm formation, we grew E. coli on media composed of pig dung or commonly contaminated foods, such as beef, chicken, and spinach. Each of these medium types provided a nutritional environment that supported matrix production and biofilm formation. Altogether, we showed that common, nonhost reservoirs of E. coli supported the formation of biofilms that subsequently protected E. coli against predation. PMID:25192998

  16. CcpA Regulates Biofilm Formation and Competence in Streptococcus gordonii

    PubMed Central

    Zheng, Lanyan; Chen, Zhiyun; Itzek, Andreas; Herzberg, Mark C.; Kreth, Jens

    2011-01-01

    Summary Streptococcus gordonii is an important member of the oral biofilm community. As oral commensal streptococci, S. gordonii is considered beneficial in promoting biofilm homeostasis. CcpA is known as central regulator of carbon catabolite repression in Gram-positive bacteria and is also involved in the control of virulence gene expression. To further establish the role of CcpA as central regulator in S. gordonii, the effect of CcpA on biofilm formation and natural competence of S. gordonii was investigated. These phenotypic traits have been suggested to be important to oral streptococci in coping with environmental stress. Here we demonstrate that a CcpA mutant was severely impaired in its biofilm forming ability, showed a defect in extracellular polysaccharide production and reduced competence. The data suggest that CcpA is involved in the regulation of biofilm formation and competence development in S. gordonii. PMID:22394467

  17. Biofilm formation and local electrostatic force characteristics of Escherichia coli O157:H7 observed by electrostatic force microscopy

    NASA Astrophysics Data System (ADS)

    Oh, Y. J.; Jo, W.; Yang, Y.; Park, S.

    2007-04-01

    The authors report growth media dependence of electrostatic force characteristics in Escherichia coli O157:H7 biofilm through local measurement by electrostatic force microscopy (EFM). The difference values of electrostatic interaction between the bacterial surface and the abiotic surface show an exponential decay behavior during biofilm development. In the EFM data, the biofilm in the low nutrient media shows a faster decay than the biofilm in the rich media. The surface potential in the bacterial cells was changed from 957to149mV. Local characterization of extracellular materials extracted from the bacteria reveals the progress of the biofilm formation and functional complexities.

  18. 2D Model for Diffusion of Oxygen with Biochemical Reaction During Biofilm Formation Process in Static Aqueous Medium

    NASA Astrophysics Data System (ADS)

    Puyate, Y. T.; Rim-Rukeh, A.

    A 2D model that describes diffusion of oxygen with biochemical reaction during biofilm formation process in static aqueous medium is presented. The analysis is based on X60 steel placed at the bottom of a container containing produced water inoculated with Leptothrix discophora (iron-oxidizing bacteria). These bacteria form biofilms on the exposed surfaces of the metal. The biofilm-microorganisms absorb oxygen from the produced water through biochemical reaction, resulting in transfer of oxygen from the bulk liquid phase to the biofilm. Predictions of the model are compared with experimental data and good agreement is obtained.

  19. Biofilm Formation by Staphylococcus epidermidis on Foldable and Rigid Intraocular Lenses

    PubMed Central

    Fazly Bazzaz, Bibi Sedigheh; Jalalzadeh, Monireh; Sanati, Maryam; Zarei-Ghanavati, Syamak; Khameneh, Bahman

    2014-01-01

    Background: Biofilm formation of Staphylococcus epidermidis is a major etiological factor of inducing device-related infections. Objectives: The ability of biofilm formation by the S. epidermidis was assessed in vitro on two brands of foldable (hydrophilic) and two brands of rigid (hydrophobic) intraocular lens materials in order to investigate the role of lens material in postoperative endophthalmitis. Materials and Methods: To ensure reproducibility of biofilm formation on intraocular lenses, two strains of S. epidermidis and three quantification methods were performed. The S. epidermidis strains, DSMZ3270 (biofilm-producer) and ATCC12228 (non-biofilm-producer) were applied. Organisms were cultivated on disks of different brands of foldable hydrophilic Intra Ocular Lens (IOL) made of acrylic (Didar, Iran; (A) and Omni, India; (B)), and rigid hydrophobic IOL made of polymethyl methacrylate (PMMA; Didar, Iran; (C) and Hexavision, France; (D)). Biofilms were stained with crystal violet (CV) dye, which is an index of biofilm formation. The bacterial population was counted after biofilm homogenization. Scanning electron microscopy (SEM) was performed to examine the extent of biofilm formation. Results: Adherence of DSMZ3270 strain on both types of foldable and rigid IOLs, was significantly more than ATCC12228 (P < 0.001-0.05 and, P < 0.01-0.05, respectively). The bacterial populations between the lenses were significantly different (P < 0.05). Subsequent studies demonstrated significant differences between brands of foldable and PMMA IOLs. According to statistical analyses the incubation time influenced the biofilm formation on both types of IOLs which meant that by increasing incubation time, the biofilm formation increased. According to the SEM pictures, biofilm seems to be lysed at 72 hours. Conclusions: These data demonstrated that the attachment of bacteria to hydrophilic acrylic IOLs was more than hydrophobic PMMA ones independent of the brand. According to these results the bacterial strain might have more hydrophilic properties. Augmenting the biomass of biofilm by passing of time demonstrated the key role of time in biofilm formation on the IOL surfaces. The differences between IOL brands in the biofilm formation indicated the influence of design parameters for IOLs. PMID:25147711

  20. Action of antimicrobial substances produced by different oil reservoir Bacillus strains against biofilm formation.

    PubMed

    Korenblum, E; Sebastin, G V; Paiva, M M; Coutinho, C M L M; Magalhes, F C M; Peyton, B M; Seldin, L

    2008-05-01

    Microbial colonization of petroleum industry systems takes place through the formation of biofilms, and can result in biodeterioration of the metal surfaces. In a previous study, two oil reservoir Bacillus strains (Bacillus licheniformis T6-5 and Bacillus firmus H(2)O-1) were shown to produce antimicrobial substances (AMS) active against different Bacillus strains and a consortium of sulfate-reducing bacteria (SRB) on solid medium. However, neither their ability to form biofilms nor the effect of the AMS on biofilm formation was adequately addressed. Therefore, here, we report that three Bacillus strains (Bacillus pumilus LF4 -- used as an indicator strain, B. licheniformis T6-5, and B. firmus H(2)O-1), and an oil reservoir SRB consortium (T6lab) were grown as biofilms on glass surfaces. The AMS produced by strains T6-5 and H(2)O-1 prevented the formation of B. pumilus LF4 biofilm and also eliminated pre-established LF4 biofilm. In addition, the presence of AMS produced by H(2)O-1 reduced the viability and attachment of the SRB consortium biofilm by an order of magnitude. Our results suggest that the AMS produced by Bacillus strains T6-5 and H(2)O-1 may have a potential for pipeline-cleaning technologies to inhibit biofilm formation and consequently reduce biocorrosion. PMID:18330565

  1. Drug susceptibility and biofilm formation of Burkholderia pseudomallei in nutrient-limited condition.

    PubMed

    Anutrakunchai, C; Sermswan, R W; Wongratanacheewin, S; Puknun, A; Taweechaisupapong, S

    2015-06-01

    Burkholderia pseudomallei is the causative agent of melioidosis, which can form biofilms and microcolonies in vivo and in vitro. One of the hallmark characteristics of the biofilm-forming bacteria is that they can be up to 1,000 times more resistant to antibiotics than their free-living counterpart. Bacteria also become highly tolerant to antibiotics when nutrients are limited. One of the most important causes of starvation induced tolerance in vivo is biofilm growth. However, the effect of nutritional stress on biofilm formation and drug tolerance of B. pseudomallei has never been reported. Therefore, this study aims to determine the effect of nutrient-limited and enriched conditions on drug susceptibility of B. pseudomallei in both planktonic and biofilm forms in vitro using broth microdilution method and Calgary biofilm device, respectively. The biofilm formation of B. pseudomallei in nutrient-limited and enriched conditions was also evaluated by a modified microtiter-plate test. Six isolates of ceftazidime (CAZ)-susceptible and four isolates of CAZ-resistant B. pseudomallei were used. The results showed that the minimum bactericidal concentrations of CAZ against B. pseudomallei in nutrient-limited condition were higher than those in enriched condition. The drug susceptibilities of B. pseudomallei biofilm in both enriched and nutrient-limited conditions were more tolerant than those of planktonic cells. Moreover, the quantification of biofilm formation by B. pseudomallei in nutrient-limited condition was significantly higher than that in enriched condition. These data indicate that nutrient-limited condition could induce biofilm formation and drug tolerance of B. pseudomallei. PMID:26691259

  2. Filaments in curved streamlines: Rapid formation of Staphylococcus aureus biofilm streamers

    PubMed Central

    Kim, Minyoung Kevin; Drescher, Knut; Pak, On Shun; Bassler, Bonnie L.; Stone, Howard A.

    2014-01-01

    Biofilms are surface-associated conglomerates of bacteria that are highly resistant to antibiotics. These bacterial communities can cause chronic infections in humans by colonizing, for example, medical implants, heart valves, or lungs. Staphylococcus aureus, a notorious human pathogen, causes some of the most common biofilm-related infections. Despite the clinical importance of S. aureus biofilms, it remains mostly unknown how physical effects, in particular flow, and surface structure influence biofilm dynamics. Here we use model microfluidic systems to investigate how environmental factors, such as surface geometry, surface chemistry, and fluid flow affect biofilm development in S. aureus. We discovered that S. aureus rapidly forms flow-induced, filamentous biofilm streamers, and furthermore if surfaces are coated with human blood plasma, streamers appear within minutes and clog the channels more rapidly than if the channels are uncoated. To understand how biofilm streamer filaments reorient in flows with curved streamlines to bridge the distances between corners, we developed a mathematical model based on resistive force theory of slender filaments. Understanding physical aspects of biofilm formation in S. aureus may lead to new approaches for interrupting biofilm formation of this pathogen. PMID:25484614

  3. Filaments in curved flow: Rapid formation of Staphylococcus aureus biofilm streamers

    NASA Astrophysics Data System (ADS)

    Kim, Min Young; Drescher, Knut; Pak, On Shun; Bassler, Bonnie L.; Stone, Howard A.

    2014-03-01

    Biofilms are surface-associated conglomerates of bacteria that are highly resistant to antibiotics. These bacterial communities can cause chronic infections in humans by colonizing, for example, medical implants, heart valves, or lungs. Staphylococcus aureus, a notorious human pathogen, causes some of the most common biofilm-related infections. Despite the clinical importance of S. aureus biofilms, it remains mostly unknown how physical effects, in particular flow, and surface structure influence biofilm dynamics. Here we use model microfluidic systems to investigate how environmental factors, such as surface geometry, surface chemistry, and fluid flow affect biofilm development in S. aureus.We discovered that S. aureus rapidly forms flow-induced, filamentous biofilm streamers, and furthermore if surfaces are coated with human blood plasma, streamers appear within minutes and clog the channels more rapidly than if the channels are uncoated. To understand how biofilm streamer filaments reorient in curved flow to bridge the distances between corners, we developed a mathematical model based on resistive force theory and slender filaments. Understanding physical aspects of biofilm formation in S. aureus may lead to new approaches for interrupting biofilm formation of this pathogen.

  4. Filaments in curved streamlines: rapid formation of Staphylococcus aureus biofilm streamers

    NASA Astrophysics Data System (ADS)

    Kim, Minyoung Kevin; Drescher, Knut; Pak, On Shun; Bassler, Bonnie L.; Stone, Howard A.

    2014-06-01

    Biofilms are surface-associated conglomerates of bacteria that are highly resistant to antibiotics. These bacterial communities can cause chronic infections in humans by colonizing, for example, medical implants, heart valves, or lungs. Staphylococcus aureus, a notorious human pathogen, causes some of the most common biofilm-related infections. Despite the clinical importance of S. aureus biofilms, it remains mostly unknown how physical effects, in particular flow, and surface structure influence biofilm dynamics. Here we use model microfluidic systems to investigate how environmental factors, such as surface geometry, surface chemistry, and fluid flow affect biofilm development of S. aureus. We discovered that S. aureus rapidly forms flow-induced, filamentous biofilm streamers, and furthermore if surfaces are coated with human blood plasma, streamers appear within minutes and clog the channels more rapidly than if the channels are uncoated. To understand how biofilm streamer filaments reorient in flows with curved streamlines to bridge the distances between corners, we developed a mathematical model based on resistive force theory of slender filaments. Understanding physical aspects of biofilm formation of S. aureus may lead to new approaches for interrupting biofilm formation of this pathogen.

  5. Inhibition of Streptococcus mutans biofilm formation, extracellular polysaccharide production, and virulence by an oxazole derivative.

    PubMed

    Chen, Lulu; Ren, Zhi; Zhou, Xuedong; Zeng, Jumei; Zou, Jing; Li, Yuqing

    2016-01-01

    Dental caries, a biofilm-related oral disease, is a result of disruption of the microbial ecological balance in the oral environment. Streptococcus mutans, which is one of the primary cariogenic bacteria, produces glucosyltransferases (Gtfs) that synthesize extracellular polysaccharides (EPSs). The EPSs, especially water-insoluble glucans, contribute to the formation of dental plaque, biofilm stability, and structural integrity, by allowing bacteria to adhere to tooth surfaces and supplying the bacteria with protection against noxious stimuli and other environmental attacks. The identification of novel alternatives that selectively inhibit cariogenic organisms without suppressing oral microbial residents is required. The goal of the current study is to investigate the influence of an oxazole derivative on S. mutans biofilm formation and the development of dental caries in rats, given that oxazole and its derivatives often exhibit extensive and pharmacologically important biological activities. Our data shows that one particular oxazole derivative, named 5H6, inhibited the formation of S. mutans biofilms and prevented synthesis of extracellular polysaccharides by antagonizing Gtfs in vitro, without affecting the growth of the bacteria. In addition, topical applications with the inhibitor resulted in diminished incidence and severity of both smooth and sulcal surface caries in vivo with a lower percentage of S. mutans in the animals' dental plaque compared to the control group (P?biofilm formation and cariogenicity of S. mutans. PMID:26526453

  6. Spatiotemporal distribution of different extracellular polymeric substances and filamentation mediate Xylella fastidiosa adhesion and biofilm formation.

    PubMed

    Janissen, Richard; Murillo, Duber M; Niza, Barbara; Sahoo, Prasana K; Nobrega, Marcelo M; Cesar, Carlos L; Temperini, Marcia L A; Carvalho, Hernandes F; de Souza, Alessandra A; Cotta, Monica A

    2015-01-01

    Microorganism pathogenicity strongly relies on the generation of multicellular assemblies, called biofilms. Understanding their organization can unveil vulnerabilities leading to potential treatments; spatially and temporally-resolved comprehensive experimental characterization can provide new details of biofilm formation, and possibly new targets for disease control. Here, biofilm formation of economically important phytopathogen Xylella fastidiosa was analyzed at single-cell resolution using nanometer-resolution spectro-microscopy techniques, addressing the role of different types of extracellular polymeric substances (EPS) at each stage of the entire bacterial life cycle. Single cell adhesion is caused by unspecific electrostatic interactions through proteins at the cell polar region, where EPS accumulation is required for more firmly-attached, irreversibly adhered cells. Subsequently, bacteria form clusters, which are embedded in secreted loosely-bound EPS, and bridged by up to ten-fold elongated cells that form the biofilm framework. During biofilm maturation, soluble EPS forms a filamentous matrix that facilitates cell adhesion and provides mechanical support, while the biofilm keeps anchored by few cells. This floating architecture maximizes nutrient distribution while allowing detachment upon larger shear stresses; it thus complies with biological requirements of the bacteria life cycle. Using new approaches, our findings provide insights regarding different aspects of the adhesion process of X. fastidiosa and biofilm formation. PMID:25891045

  7. Spatiotemporal distribution of different extracellular polymeric substances and filamentation mediate Xylella fastidiosa adhesion and biofilm formation

    PubMed Central

    Janissen, Richard; Murillo, Duber M.; Niza, Barbara; Sahoo, Prasana K.; Nobrega, Marcelo M.; Cesar, Carlos L.; Temperini, Marcia L. A.; Carvalho, Hernandes F.; de Souza, Alessandra A.; Cotta, Monica A.

    2015-01-01

    Microorganism pathogenicity strongly relies on the generation of multicellular assemblies, called biofilms. Understanding their organization can unveil vulnerabilities leading to potential treatments; spatially and temporally-resolved comprehensive experimental characterization can provide new details of biofilm formation, and possibly new targets for disease control. Here, biofilm formation of economically important phytopathogen Xylella fastidiosa was analyzed at single-cell resolution using nanometer-resolution spectro-microscopy techniques, addressing the role of different types of extracellular polymeric substances (EPS) at each stage of the entire bacterial life cycle. Single cell adhesion is caused by unspecific electrostatic interactions through proteins at the cell polar region, where EPS accumulation is required for more firmly-attached, irreversibly adhered cells. Subsequently, bacteria form clusters, which are embedded in secreted loosely-bound EPS, and bridged by up to ten-fold elongated cells that form the biofilm framework. During biofilm maturation, soluble EPS forms a filamentous matrix that facilitates cell adhesion and provides mechanical support, while the biofilm keeps anchored by few cells. This floating architecture maximizes nutrient distribution while allowing detachment upon larger shear stresses; it thus complies with biological requirements of the bacteria life cycle. Using new approaches, our findings provide insights regarding different aspects of the adhesion process of X. fastidiosa and biofilm formation. PMID:25891045

  8. Manganese Ion Increases LAB-yeast Mixed-species Biofilm Formation

    PubMed Central

    NOZAKA, Soma; FURUKAWA, Soichi; SASAKI, Miwa; HIRAYAMA, Satoru; OGIHARA, Hirokazu; MORINAGA, Yasushi

    2014-01-01

    Remarkable LAB-yeast mixed-species biofilm was formed by lactic acid bacteria (LAB) Lactobacillus plantarum ML11-11 isolated from Fukuyama pot vinegar and Saccharomyces cerevisiae. This mixed-species biofilm formation increased in proportion to the YPD medium concentration but decreased in proportion to the MRS medium concentration. The effect of MRS components on mixed-species biofilm formation was investigated in a YPD medium environment, and it was clarified that beef extract (one of the MRS medium components) decreased mixed-species biofilm formation. On the other hand, manganese sulfate (another component in MRS) remarkably increased both LAB single- and LAB-yeast mixed-species biofilm formation. LAB single- and mixed-species biofilm formation were increased in proportion to the manganese sulfate concentration up to 1 mM and 100 μM, respectively. The growth of L. plantarum ML11-11 was increased significantly by the addition of 10 μM manganese sulfate and was resistant to higher concentration of up to 100 mM, but growth of S. cerevisiae was sensitive to manganese ion above 100 μM. These results suggested that mixed-species biofilm formation could be controlled artificially by controlling the manganese ion level. PMID:25003021

  9. Effects of growth conditions on biofilm formation by Actinobacillus pleuropneumoniae

    PubMed Central

    Labrie, Josée; Pelletier-Jacques, Geneviève; Deslandes, Vincent; Ramjeet, Mahendrasingh; Auger, Eliane; Nash, John H.E.; Jacques, Mario

    2010-01-01

    Biofilm formation is an important virulence trait of many bacterial pathogens. It has been reported in the literature that only two of the reference strains of the swine pathogen Actinobacillus pleuropneumoniae, representing serotypes 5b and 11, were able to form biofilm in vitro. In this study, we compared biofilm formation by the serotype 1 reference strain S4074 of A. pleuropneumoniae grown in five different culture media. We observed that strain S4074 of A. pleuropneumoniae is able to form biofilms after growth in one of the culture conditions tested brain heart infusion (BHI medium, supplier B). Confocal laser scanning microscopy using a fluorescent probe specific to the poly-N-acetylglucosamine (PGA) polysaccharide further confirmed biofilm formation. In accordance, biofilm formation was susceptible to dispersin B, a PGA hydrolase. Transcriptional profiles of A. pleuropneumoniae S4074 following growth in BHI-B, which allowed a robust biofilm formation, and in BHI-A, in which only a slight biofilm formation was observed, were compared. Genes such as tadC, tadD, genes with homology to autotransporter adhesins as well as genes pgaABC involved in PGA biosynthesis and genes involved in zinc transport were up-regulated after growth in BHI-B. Interestingly, biofilm formation was inhibited by zinc, which was found to be more present in BHI-A (no or slight biofilm) than in BHI-B. We also observed biofilm formation in reference strains representing serotypes 3, 4, 5a, 12 and 14 as well as in 20 of the 37 fresh field isolates tested. Our data indicate that A. pleuropneumoniae has the ability to form biofilms under appropriate growth conditions and transition from a biofilm-positive to a biofilm-negative phenotype was reversible. PMID:19737507

  10. Inhibition of Salmonella enterica Biofilm Formation Using Small-Molecule Adenosine Mimetics

    PubMed Central

    Koopman, Jacob A.; Marshall, Joanna M.; Bhatiya, Aditi; Eguale, Tadesse; Kwiek, Jesse J.

    2014-01-01

    Biofilms have been widely implicated in chronic infections and environmental persistence of Salmonella enterica, facilitating enhanced colonization of surfaces and increasing the ability of the bacteria to be transmitted to new hosts. Salmonella enterica serovar Typhi biofilm formation on gallstones from humans and mice enhances gallbladder colonization and bacterial shedding, while Salmonella enterica serovar Typhimurium biofilms facilitate long-term persistence in a number of environments important to food, medical, and farming industries. Salmonella regulates expression of many virulence- and biofilm-related processes using kinase-driven pathways. Kinases play pivotal roles in phosphorylation and energy transfer in cellular processes and possess an ATP-binding pocket required for their functions. Many other cellular proteins also require ATP for their activity. Here we test the hypothesis that pharmacological interference with ATP-requiring enzymes utilizing adenosine mimetic compounds would decrease or inhibit bacterial biofilm formation. Through the screening of a 3,000-member ATP mimetic library, we identified a single compound (compound 7955004) capable of significantly reducing biofilm formation by S. Typhimurium and S. Typhi. The compound was not bactericidal or bacteriostatic toward S. Typhimurium or cytotoxic to mammalian cells. An ATP-Sepharose affinity matrix technique was used to discover potential protein-binding targets of the compound and identified GroEL and DeoD. Compound 7955004 was screened against other known biofilm-forming bacterial species and was found to potently inhibit biofilms of Acinetobacter baumannii as well. The identification of a lead compound with biofilm-inhibiting capabilities toward Salmonella provides a potential new avenue of therapeutic intervention against Salmonella biofilm formation, with applicability to biofilms of other bacterial pathogens. PMID:25313216

  11. Biofilms Formed by Gram-Negative Bacteria Undergo Increased Lipid A Palmitoylation, Enhancing In Vivo Survival

    PubMed Central

    Chalabaev, Sabina; Chauhan, Ashwini; Novikov, Alexey; Iyer, Pavithra; Szczesny, Magdalena; Beloin, Christophe; Caroff, Martine

    2014-01-01

    ABSTRACT Bacterial biofilm communities are associated with profound physiological changes that lead to novel properties compared to the properties of individual (planktonic) bacteria. The study of biofilm-associated phenotypes is an essential step toward control of deleterious effects of pathogenic biofilms. Here we investigated lipopolysaccharide (LPS) structural modifications in Escherichia coli biofilm bacteria, and we showed that all tested commensal and pathogenic E. coli biofilm bacteria display LPS modifications corresponding to an increased level of incorporation of palmitate acyl chain (palmitoylation) into lipid A compared to planktonic bacteria. Genetic analysis showed that lipid A palmitoylation in biofilms is mediated by the PagP enzyme, which is regulated by the histone-like protein repressor H-NS and the SlyA regulator. While lipid A palmitoylation does not influence bacterial adhesion, it weakens inflammatory response and enhances resistance to some antimicrobial peptides. Moreover, we showed that lipid A palmitoylation increases in vivo survival of biofilm bacteria in a clinically relevant model of catheter infection, potentially contributing to biofilm tolerance to host immune defenses. The widespread occurrence of increased lipid A palmitoylation in biofilms formed by all tested bacteria suggests that it constitutes a new biofilm-associated phenotype in Gram-negative bacteria. PMID:25139899

  12. Chemically Specific Cellular Imaging of Biofilm Formation

    SciTech Connect

    Herberg, J L; Schaldach, C; Horn, J; Gjersing, E; Maxwell, R

    2006-02-09

    This document and the accompanying manuscripts summarize the technical accomplishments for our one-year LDRD-ER effort. Biofilm forming microbes have existed on this planet for billions of years and make up 60% of the biological mass on earth. Such microbes exhibit unique biochemical pathways during biofilm formation and play important roles in human health and the environment. Microbial biofilms have been directly implicated in, for example, product contamination, energy losses, and medical infection that cost the loss of human lives and billions of dollars. In no small part due to the lack of detailed understanding, biofilms unfortunately are resistant to control, inhibition, and destruction, either through treatment with antimicrobials or immunological defense mechanisms of the body. Current biofilm research has concentrated on the study of biofilms in the bulk. This is primarily due to the lack of analytical and physical tools to study biofilms non-destructively, in three dimensions, and on the micron or sub-micron scale. This has hindered the development of a clear understanding of either the early stage mechanisms of biofilm growth or the interactions of biofilms with their environment. Enzymatic studies have deduced a biochemical reaction that results in the oxidation of reduced sulfur species with the concomitant reduction of nitrate, a common groundwater pollutant, to dinitrogen gas by the bacterium, Thiobacillus denitrificans (TD). Because of its unique involvement in biologically relevant environmental pathways, TD is scheduled for genome sequencing in the near future by the DOE's Joint Genome Institute and is of interest to DOE's Genomes to Life Program. As our ecosystem is exposed to more and more nitrate contamination large scale livestock and agricultural practices, a further understanding of biofilm formation by organisms that could alleviate these problems is necessary in order to protect out biosphere. However, in order to study this complicated organism, we needed to first turn our attention to a well understood organism. Pseudomonas aeruginosa (PA) is a well-studied organism and will be used to compare our results with others. Then, we will turn our attention to TD. It is expected that the research performed will provide key data to validate biochemical studies of TD and result in high profile publications in leading journals. For this project, our ultimate goal was to combine both Magnetic Resonance Imaging (MRI) and Nuclear Magnetic Resonance (NMR) experimental analysis with computer simulations to provide unique 3D molecular structural, dynamics, and functional information on the order of microns for this DOE mission relevant microorganism, T. denitrificans. For FY05, our goals were to: (1) Determine proper media for optimal growth of PA; growth rate measurements in that media and characterization of metabolite signatures during growth via {sup 1}H and {sup 13}C NMR, (2) Determine and build mineral, metal, and implant material surfaces to support growth of PA, (3) Implementing new MRI sequences to image biofilms more efficiently and increase resolution with new hardware design, (4) Develop further diffusion and flow MRI measurements of biofilms and biofilm formation with different MRI pulse sequences and different hardware design, and (5) Develop a zero dimension model of the rate of growth and the metabolite profiles of PA. Our major accomplishments are discussed in the following text. However, the bulk of this work is described in the attached manuscript entitled, ''NMR Metabolomics of Planktonic and Biofilm Modes of Growth in Pseudomonas aeruginosa''. This paper will be submitted to the Journal of Bacteriology in coming weeks. In addition, this one-year effort has lead to our incorporation into the Enhanced Surveillance Campaign during FY05 for some proof-of-principle MRI measurements on polymers. We are currently using similar methods to evaluate these polymers. In addition, this work on MRI measurements on polymers has lead to a paper entitled, ''Characterization of local deformation in filled-silicone elastomers subject to high strain NMR MOUSE and Magnetic Resonance Imaging as a diagnostic tool for detection of inhomogeneities''.

  13. Future perspective on host-pathogen interactions during bacterial biofilm formation within the nasopharynx

    PubMed Central

    Blanchette, Krystle A; Orihuela, Carlos J

    2012-01-01

    Nasopharyngeal colonization provides bacteria with a place of residence, a platform for person-to-person transmission and for many opportunistic pathogens it is a prerequisite event towards the development of invasive disease. Therefore, how host factors within the nasopharynx contribute to, inhibit or otherwise shape biofilm formation, the primary mode of existence for colonizing bacteria, and how biofilm bacteria subvert the acute inflammatory response that facilitates clearance, are important topics for future microbiological research. This review proposes the examination of host components as bridging molecules for bacterial interactions during biofilm formation, altered virulence determinant production and cell wall modification as a mechanism for immunoquiescence, and the role of host factors as signals and co-opted mechanisms for bacterial dissemination, together providing an opportunity for disease. PMID:22324992

  14. MgrA represses biofilm formation in Staphylococcus aureus.

    PubMed

    Trotonda, Mara Pilar; Tamber, Sandeep; Memmi, Guido; Cheung, Ambrose L

    2008-12-01

    MgrA is a pleiotropic regulator that controls autolysis, virulence, and efflux pump activity in Staphylococcus aureus. We recently found that mgrA mutants of strains RN6390, SH1000, and MW2 also displayed enhanced biofilm formation compared with their respective parents. The biofilms formed by mgrA mutants of RN6390 and MW2 are independent of sigB and ica loci, two genetic elements that have been previously associated with biofilm formation in S. aureus. Biofilms formed by mgrA mutants are dependent on the expression of surface proteins mediated by the sortase gene srtA. Extracellular DNA was also a crucial component of the early biofilm of mgrA mutants. Genetic analysis indicated that biofilm formation in mgrA mutants is mediated in part by agr RNAIII, a genetic locus regulated by mgrA. Additionally, SarA is important to biofilm formation in mgrA mutants since the double sarA mgrA mutants failed to form biofilms compared to single mgrA mutants of RN6390 and MW2. However, the SarA-mediated effect is independent of agr and proteases such as V8 protease and aureolysin. Collectively, our data showed MgrA to be a repressor of biofilm formation, and biofilms formed by mgrA mutants have features that are distinct from other reported biofilm types in S. aureus. PMID:18852246

  15. MgrA Represses Biofilm Formation in Staphylococcus aureus?

    PubMed Central

    Trotonda, Mara Pilar; Tamber, Sandeep; Memmi, Guido; Cheung, Ambrose L.

    2008-01-01

    MgrA is a pleiotropic regulator that controls autolysis, virulence, and efflux pump activity in Staphylococcus aureus. We recently found that mgrA mutants of strains RN6390, SH1000, and MW2 also displayed enhanced biofilm formation compared with their respective parents. The biofilms formed by mgrA mutants of RN6390 and MW2 are independent of sigB and ica loci, two genetic elements that have been previously associated with biofilm formation in S. aureus. Biofilms formed by mgrA mutants are dependent on the expression of surface proteins mediated by the sortase gene srtA. Extracellular DNA was also a crucial component of the early biofilm of mgrA mutants. Genetic analysis indicated that biofilm formation in mgrA mutants is mediated in part by agr RNAIII, a genetic locus regulated by mgrA. Additionally, SarA is important to biofilm formation in mgrA mutants since the double sarA mgrA mutants failed to form biofilms compared to single mgrA mutants of RN6390 and MW2. However, the SarA-mediated effect is independent of agr and proteases such as V8 protease and aureolysin. Collectively, our data showed MgrA to be a repressor of biofilm formation, and biofilms formed by mgrA mutants have features that are distinct from other reported biofilm types in S. aureus. PMID:18852246

  16. Biofilm formation of Clostridium perfringens and its exposure to low-dose antimicrobials

    PubMed Central

    Charlebois, Audrey; Jacques, Mario; Archambault, Marie

    2014-01-01

    Clostridium perfringens is an opportunistic pathogen that can cause food poisoning in humans and various enterotoxemia in animal species. Very little is known on the biofilm of C. perfringens and its exposure to subminimal inhibitory concentrations of antimicrobials. This study was undertaken to address these issues. Most of the C. perfringens human and animal isolates tested in this study were able to form biofilm (230/277). Porcine clinical isolates formed significantly more biofilm than the porcine commensal isolates. A subgroup of clinical and commensal C. perfringens isolates was randomly selected for further characterization. Biofilm was found to protect C. perfringens bacterial cells from exposure to high concentrations of tested antimicrobials. Exposure to low doses of some of these antimicrobials tended to lead to a diminution of the biofilm formed. However, a few isolates showed an increase in biofilm formation when exposed to low doses of tylosin, bacitracin, virginiamycin, and monensin. Six isolates were randomly selected for biofilm analysis using scanning laser confocal microscopy. Of those, four produced more biofilm in presence of low doses of bacitracin whereas biofilms formed without bacitracin were thinner and less elevated. An increase in the area occupied by bacteria in the biofilm following exposure to low doses of bacitracin was also observed in the majority of isolates. Morphology examination revealed flat biofilms with the exception of one isolate that demonstrated a mushroom-like biofilm. Matrix composition analysis showed the presence of proteins, beta-1,4 linked polysaccharides and extracellular DNA, but no poly-beta-1,6-N-acetyl-D-glucosamine. This study brings new information on the biofilm produced by C. perfringens and its exposure to low doses of antimicrobials. PMID:24795711

  17. Composition and Susceptibility to Chlorhexidine of Multispecies Biofilms of Oral Bacteria

    PubMed Central

    Pratten, J.; Barnett, P.; Wilson, M.

    1998-01-01

    Using a constant-depth film fermentor, we have grown a six-membered biofilm community with a bacterial composition similar to that found in supragingival dental plaque. Cryosectioning revealed the distribution of bacteria throughout the biofilm. Exposure to 0.2% chlorhexidine for up to 5 min had little effect on biofilm viability. PMID:9726908

  18. A Movable Surface: Formation of Yersinia sp. Biofilms on Motile Caenorhabditis elegans

    PubMed Central

    Tan, Li; Darby, Creg

    2004-01-01

    Bubonic plague is transmitted by fleas whose feeding is blocked by a mass of Yersinia pestis in the digestive tract. Y. pestis and the closely related Y. pseudotuberculosis also block the feeding of Caenorhabditis elegans by forming a biofilm on the nematode head. C. elegans mutants with severe motility defects acquire almost no biofilm, indicating that normal animals accumulate the biofilm matrix as they move through a Yersinia lawn. Using the lectin wheat germ agglutinin as a probe, we show that the matrix on C. elegans contains carbohydrate produced by Yersinia. The carbohydrate is present in bacterial lawns prior to addition of nematodes, indicating that biofilm formation does not involve signaling between the two organisms. Furthermore, biofilm accumulation depends on continuous C. elegans exposure to a lawn of Yersinia bacteria. PMID:15262945

  19. [Activation of formation of bacterial biofilms by azithromycin and prevention of this effect].

    PubMed

    Mart'ianov, S V; Zhurina, M V; Él'-Registan, G I; Plakunov, V K

    2015-01-01

    Growth of members of most of the studied genera of gram-positive (Dietzia, Kocuria, and Rhodo- coccus) and gram-negative bacteria (Pseudomonas and Chromobacterium) in biofilms exhibited higher resistance to an translation inhibitor, azithromycin compared to the growth of planktonic cultures of the same strains. Low concentrations of azithromycin were found to stimulate biofilm formation by the studied saprotrophic strains. The rate of synthesis of the polysaccharide matrix component exceeded the rate of cell growth, indicating implementation of the biofilm phenotype under these conditions. It was found that an alkylhydroxybenzene (AHB) compound 4-hexylresorcinol was capable of almost uniform suppression of growth of both planktonic cultures and biofilms of the saprotrophic strains under study. In some cases, combined action ofazithromycin and AHB resulted in an additive inhibitory effect and prevented the stimulation of biofilm growth by subinhibitory azithromycin concentrations. Thus, AHB may be considered a promising antibiofilm agent. PMID:25916144

  20. CdiGMP signaling at early stages of biofilm formation in Pseudomonas Aeruginosa

    NASA Astrophysics Data System (ADS)

    Zhao, Kun; Gibiansky, Maxsim; Xian, Wujing; Utada, Andrew; Wong, Gerard

    2014-03-01

    Biofilm communities on surfaces constitute an important physiological state of bacteria. CdiGMP is a secondary messenger that has recently emerged as a master regulator of biofilm behavior. It has been shown that cdiGMP can affect bacterial adhesion, motility and exopolysaccharides production, which are important in regulating biofilm formation. However, at a single cell level, the details of how cdiGMP regulate bacterial behavior are largely unknown. Here we examine the dynamics of intracellular cdiGMP levels at early stages of biofilm in Pseudomonas Aeruginosa, by using cell tracking techniques. We show that cells with different cdiGMP levels play different roles in the microcolony development at early stages of biofilm. The correlation between Psl and cdiGMP levels is also investigated.

  1. Detection of Bacteria Bearing Resistant Biofilm Forms, by Using the Universal and Specific PCR is Still Unhelpful in the Diagnosis of Periprosthetic Joint Infections

    PubMed Central

    Zegaer, Batool H.; Ioannidis, Anastasios; Babis, George C.; Ioannidou, Vassiliki; Kossyvakis, Athanassios; Bersimis, Sotiris; Papaparaskevas, Joseph; Petinaki, Efthimia; Pliatsika, Paraskevi; Chatzipanagiotou, Stylianos

    2014-01-01

    Intraoperative conventional bacteriological cultures were compared with different polymerase chain reaction (PCR) methods in patients with total joint arthroplasties. The isolated bacteria were investigated for biofilm formation, and the biofilm forming strains, in their planktonic and biofilm forms, were further tested for their antimicrobial resistance against several clinically important antimicrobials. Forty four bone and joint samples were included and classified as infected or non-infected according to standard criteria for periprosthetic hip and knee infections. For the bacteriological diagnosis, conventional culture, two types of universal PCR and species specific PCR for three selected pathogens (Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa) were applied. Biofilm formation determination was performed by the tissue culture plate method. Antimicrobial susceptibility of the planktonic bacteria was performed by the minimal inhibitory concentration determination and, of the biofilm forms, by the minimal inhibitory concentration for bacterial regrowth from the biofilm. Twenty samples were culture positive, with S. epidermidis, S. aureus, or P. aeruginosa. All PCR methods were very ineffective in detecting only one pathogen. All isolates were biofilm positive and their biofilm forms, were highly resistant. In this study, compared to PCR, culture remains the “gold standard.” The biofilm formation by the causative bacteria and the concomitant manifold increased antimicrobial resistance may explain the clinical failure of treatment in some cases and should be considered in the future for therapeutic planning. PMID:25593905

  2. Detection of Bacteria Bearing Resistant Biofilm Forms, by Using the Universal and Specific PCR is Still Unhelpful in the Diagnosis of Periprosthetic Joint Infections.

    PubMed

    Zegaer, Batool H; Ioannidis, Anastasios; Babis, George C; Ioannidou, Vassiliki; Kossyvakis, Athanassios; Bersimis, Sotiris; Papaparaskevas, Joseph; Petinaki, Efthimia; Pliatsika, Paraskevi; Chatzipanagiotou, Stylianos

    2014-01-01

    Intraoperative conventional bacteriological cultures were compared with different polymerase chain reaction (PCR) methods in patients with total joint arthroplasties. The isolated bacteria were investigated for biofilm formation, and the biofilm forming strains, in their planktonic and biofilm forms, were further tested for their antimicrobial resistance against several clinically important antimicrobials. Forty four bone and joint samples were included and classified as infected or non-infected according to standard criteria for periprosthetic hip and knee infections. For the bacteriological diagnosis, conventional culture, two types of universal PCR and species specific PCR for three selected pathogens (Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa) were applied. Biofilm formation determination was performed by the tissue culture plate method. Antimicrobial susceptibility of the planktonic bacteria was performed by the minimal inhibitory concentration determination and, of the biofilm forms, by the minimal inhibitory concentration for bacterial regrowth from the biofilm. Twenty samples were culture positive, with S. epidermidis, S. aureus, or P. aeruginosa. All PCR methods were very ineffective in detecting only one pathogen. All isolates were biofilm positive and their biofilm forms, were highly resistant. In this study, compared to PCR, culture remains the "gold standard." The biofilm formation by the causative bacteria and the concomitant manifold increased antimicrobial resistance may explain the clinical failure of treatment in some cases and should be considered in the future for therapeutic planning. PMID:25593905

  3. Coexistence of antibiotic-producing and antibiotic-sensitive bacteria in biofilms is mediated by resistant bacteria.

    PubMed

    Narisawa, Naoki; Haruta, Shin; Arai, Hiroyuki; Ishii, Masaharu; Igarashi, Yasuo

    2008-06-01

    Antibiotic-sensitive bacteria have been found to coexist with antibiotic-producing bacteria in biofilms, but little is known about how the former develop in such an environment. Here we isolated pyocyanin-sensitive bacteria belonging to the genus Brevibacillus from a biofilm derived from soil extract and based on the preestablished biofilm of a pyocyanin producer, Pseudomonas aeruginosa strain P1. In addition, pyocyanin-resistant strains belonging to the genus Raoultella were isolated from the same biofilm. Microbial relationships within biofilms were examined by using three strains, strain P1, Brevibacillus strain S1, and Raoultella strain R1, each of which individually formed a biofilm within 2 days in a flow cell. Strain S1 did not fully develop on the preestablished biofilm of strain P1 during 4 days of cultivation, whereas a mutant of strain P1 which was deficient in pyocyanin production allowed strain S1 to cocolonize within a biofilm. On the other hand, strain R1 developed on the biofilm of strain P1 regardless of pyocyanin production. When mixed 1:1 inocula of strains S1 and R1 were introduced into the strain P1 biofilm, all three species were found in the 4-day biofilm. In the mixed biofilm, strain S1 was surrounded by the layer of strain R1 and seemed to be separated from strain P1 and the outflow solution. However, strain S1 did not survive in a three-species mixed culture under planktonic conditions. These results indicate that the survival of sensitive bacteria in biofilm with a pyocyanin producer is achieved by covering them with a layer of resistant bacteria. We also evaluated the influence of antibiotic production on the producer. PMID:18441106

  4. Novel application for the prevention and treatment of Staphylococcus aureus biofilm formation

    NASA Astrophysics Data System (ADS)

    Traba, Christian

    Formation of bacterial biofilms at solid-liquid interfaces creates numerous problems in both industrial and biomedical sciences. In this dissertation, the application of plasma from two very different facets was studied. In part one, the susceptibility of pre-formed Staphylococcus aureus biofilms on biomaterials to different plasmas was investigated. It was found that the distinct chemical/physical properties of plasmas generated from oxygen, nitrogen, and argon all demonstrated very potent but very different anti-biofilm mechanisms of action. An in depth analysis of these results show: 1) different reactive species produced in each plasma demonstrate specific activity, and 2) the commonly associated etching effect could be manipulated and even controlled, depending on experimental conditions and the discharge gas. These studies provide insights into the anti-biofilm mechanisms of plasma as well as the effects of different reactive species on biofilm inactivation. Under experimental parameters, bacterial cells in Staphylococcus aureus biofilms were killed (>99.9%) by plasmas within minutes of exposure and no bacteria nor biofilm re-growth from discharge gas treated biofilms was observed throughout the life-span of the re-growth experiment. The decontamination ability of plasmas for the treatment of biofilm related infections on biomedical materials was confirmed and novel applications involving the use of low power argon and oxygen for the treatment of biofilm contaminated biomaterials and indwelling devices is proposed. The second facet of this dissertation explores the interaction between biofilm forming Staphylococcus aureus bacteria on different antibacterial/anti-biofilm surfaces. The antibiotic-free anti-fouling surfaces constructed in this study were generated from the plasma-assisted graft polymerization technique. These sophisticated surfaces were stable, biocompatible and capable of preventing biofilm formation on biomaterials and medical devices. Under optimal experimental conditions, the antibacterial activities of these sophisticated surfaces had two distinct mechanisms: 1) reducing bacterial attachment and 2) eradicating adherent bacteria. The excellent antibacterial and anti-biofilm properties of these modified surfaces were initially tested in stationary cultures and later confirmed through a microfluidic cultivation system, which mimicked the in-vivo conditions of implanted catheters. Information gathered, suggests the graft polymerization of negatively charged monomers may be utilized to permanently prevent biofouling on inserted biomaterials, as well as implanted medical devices.

  5. Inhibition of biofilm formation in Bacillus subtilis by new halogenated furanones.

    PubMed

    Kayumov, Airat R; Khakimullina, Elvina N; Sharafutdinov, Irshad S; Trizna, Elena Y; Latypova, Lilia Z; Thi Lien, Hoang; Margulis, Anna B; Bogachev, Mikhail I; Kurbangalieva, Almira R

    2015-05-01

    Gram-positive bacteria can cause various infections including hospital-acquired infections. While in the biofilm, the resistance of bacteria to both antibiotics and the human immune system is increased causing difficulties in the treatment. Bacillus subtilis, a non-pathogenic Gram-positive bacterium, is widely used as a model organism for studying biofilm formation. Here we investigated the effect of novel synthesized chloro- and bromo-containing 2(5H)-furanones on biofilm formation by B. subtilis. Mucobromic acid (3,4-dibromo-5-hydroxy-2(5H)-furanone) and the two derivatives of mucochloric acid (3,4-dichloro-5-hydroxy-2(5H)-furanone)-F8 and F12-were found to inhibit the growth and to efficiently prevent biofilm formation by B. subtilis. Along with the low production of polysaccharide matrix and repression of the eps operon, strong repression of biofilm-related yqxM also occurred in the presence of furanones. Therefore, our data confirm that furanones affect significantly the regulatory pathway(s) leading to biofilm formation. We propose that the global regulator, Spo0A, is one of the potential putative cellular targets for these compounds. PMID:25335695

  6. inhibitory effects of citral, cinnamaldehyde, and tea polyphenols on mixed biofilm formation by foodborne Staphylococcus aureus and Salmonella enteritidis.

    PubMed

    Zhang, Hongmei; Zhou, Wenyuan; Zhang, Wenyan; Yang, Anlin; Liu, Yanlan; Jiang, Yan; Huang, Shaosong; Su, Jianyu

    2014-06-01

    Biofilms are significant hazards in the food industry. In this study, we investigated the effects of food additive such as citral, cinnamaldehyde, and tea polyphenols on mixed biofilm formation by foodborne Staphylococcus aureus and Salmonella serotype Enteritidis. The adhesion rates of mixed strains in sub-MIC of additives were determined by a microtiter plate assay and bacterial communication signal autoinducer 2 (AI-2) production via a bioluminescence reporter Vibrio harveyi BB170. The structure of mixed biofilm was analyzed using scanning electron microscopy. The effect of the disinfectants hydrogen peroxide, sodium hypochlorite, and peracetic acid was tested on the mixed biofilm. Our results demonstrated that citral, cinnamaldehyde, and tea polyphenols were able to significantly inhibit mixed biofilm formation, while citral could reduce the synthesis of AI-2. Conversely, we observed a significant increase in AI-2 mediated by cinnamaldehyde. Tea polyphenols at lower concentrations induced AI-2 synthesis; however, AI-2 synthesis was significantly inhibited at higher concentrations (300 m g/ml). Food additives inhibited the adhesion of mixed bacteria on stainless steel chips and increased the sensitivity of the mixed biofilm to disinfectants. In conclusion, citral, cinnamaldehyde, and tea polyphenols had strong inhibitory effects on mixed biofilm formation and also enhanced the effect of disinfectant on mixed biofilm formation. This study provides a scientific basis for the application of natural food additives to control biofilm formation of foodborne bacteria. PMID:24853514

  7. Rapid Evolution of Culture-Impaired Bacteria During Adaptation to Biofilm Growth

    PubMed Central

    Penterman, Jon; Nguyen, Dao; Anderson, Erin; Staudinger, Benjamin J.; Greenberg, Everett P.; Lam, Joseph S.; Singh, Pradeep K.

    2014-01-01

    Summary Biofilm growth increases the fitness of bacteria in harsh conditions. However, bacteria from clinical and environmental biofilms can exhibit impaired growth in culture, even when the species involved are readily cultureable, and permissive conditions are used. Here we show that culture-impaired variants of Pseudomonas aeruginosa rapidly and abundantly evolve in laboratory biofilms. The culture-impaired phenotype is caused by mutations that alter the outer-membrane lipopolysaccharide structure. Within biofilms, the lipopolysaccharide mutations markedly increase bacterial fitness. However, outside the protected biofilm environment, the mutations sensitize the variants to killing by a self-produced antimicrobial agent. Thus, a biofilm-mediated adaptation produces a stark fitness trade off that compromises bacterial survival in culture. Trade offs like this could limit the ability of bacteria to transition between biofilm growth and the free-living state, and produce bacterial populations that escape detection by culture-based sampling. PMID:24412364

  8. Multi-Channel Microfluidic Biosensor Platform Applied for Online Monitoring and Screening of Biofilm Formation and Activity

    PubMed Central

    Bruchmann, Julia; Sachsenheimer, Kai; Rapp, Bastian E.; Schwartz, Thomas

    2015-01-01

    Bacterial colonization of surfaces and interfaces has a major impact on various areas including biotechnology, medicine, food industries, and water technologies. In most of these areas biofilm development has a strong impact on hygiene situations, product quality, and process efficacies. In consequence, biofilm manipulation and prevention is a fundamental issue to avoid adverse impacts. For such scenario online, non-destructive biofilm monitoring systems become important in many technical and industrial applications. This study reports such a system in form of a microfluidic sensor platform based on the combination of electrical impedance spectroscopy and amperometric current measurement, which allows sensitive online measurement of biofilm formation and activity. A total number of 12 parallel fluidic channels enable real-time online screening of various biofilms formed by different Pseudomonas aeruginosa and Stenotrophomonas maltophilia strains and complex mixed population biofilms. Experiments using disinfectant and antibiofilm reagents demonstrate that the biofilm sensor is able to discriminate between inactivation/killing of bacteria and destabilization of biofilm structures. The impedance and amperometric sensor data demonstrated the high dynamics of biofilms as a consequence of distinct responses to chemical treatment strategies. Gene expression of flagellar and fimbrial genes of biofilms grown inside the microfluidic system supported the detected biofilm growth kinetics. Thus, the presented biosensor platform is a qualified tool for assessing biofilm formation in specific environments and for evaluating the effectiveness of antibiofilm treatment strategies. PMID:25706987

  9. Biofilm Formation and Detachment in Gram-Negative Pathogens Is Modulated by Select Bile Acids.

    PubMed

    Sanchez, Laura M; Cheng, Andrew T; Warner, Christopher J A; Townsley, Loni; Peach, Kelly C; Navarro, Gabriel; Shikuma, Nicholas J; Bray, Walter M; Riener, Romina M; Yildiz, Fitnat H; Linington, Roger G

    2016-01-01

    Biofilms are a ubiquitous feature of microbial community structure in both natural and host environments; they enhance transmission and infectivity of pathogens and provide protection from human defense mechanisms and antibiotics. However, few natural products are known that impact biofilm formation or persistence for either environmental or pathogenic bacteria. Using the combination of a novel natural products library from the fish microbiome and an image-based screen for biofilm inhibition, we describe the identification of taurine-conjugated bile acids as inhibitors of biofilm formation against both Vibrio cholerae and Pseudomonas aeruginosa. Taurocholic acid (1) was isolated from the fermentation broth of the fish microbiome-derived strain of Rhodococcus erythropolis and identified using standard NMR and MS methods. Screening of the twelve predominant human steroidal bile acid components revealed that a subset of these compounds can inhibit biofilm formation, induce detachment of preformed biofilms under static conditions, and that these compounds display distinct structure-activity relationships against V. cholerae and P. aeruginosa. Our findings highlight the significance of distinct bile acid components in the regulation of biofilm formation and dispersion in two different clinically relevant bacterial pathogens, and suggest that the bile acids, which are endogenous mammalian metabolites used to solubilize dietary fats, may also play a role in maintaining host health against bacterial infection. PMID:26992172

  10. CsgD regulatory network in a bacterial trait-altering biofilm formation

    PubMed Central

    Liu, Zhen; Niu, Hua; Wu, Shuyan; Huang, Rui

    2014-01-01

    In response to the limited nutrients and stressful conditions of their habitats, many microorganisms including Salmonella form a biofilm by secreting a polymeric matrix to interweave individual cells and to build structural communities on an abiotic or living surface. The biofilm formation in Salmonella is tightly regulated by a regulatory network that involves multiple transcriptional regulators. As a master transcriptional regulator in biofilm formation, curli subunit gene D (csgD) functions by activating the biosynthesis of the extracellular polymeric matrix composed of exopolysaccharide cellulose, curli and biofilm-associated proteins (Baps), assisting bacterial cells in transitioning from the planktonic stage to the multicellular state. The expression of CsgD itself is affected by cell growth stage and environmental stimuli through the action of other transcriptional factors, bis-(3′–5′)-cyclic dimeric guanosine monophosphate (c-di-GMP), regulatory small RNAs (sRNAs) and other elements. The formation of biofilm confers new physiological characteristics on the bacteria within, especially resistance against unfavorable environmental conditions. Herein, we summarize the CsgD regulatory network of Salmonella biofilm formation and the new traits acquired by Salmonella when within biofilm. PMID:26038492

  11. Biofilm Formation and Detachment in Gram-Negative Pathogens Is Modulated by Select Bile Acids

    PubMed Central

    Townsley, Loni; Peach, Kelly C.; Navarro, Gabriel; Shikuma, Nicholas J.; Bray, Walter M.; Riener, Romina M.; Yildiz, Fitnat H.; Linington, Roger G.

    2016-01-01

    Biofilms are a ubiquitous feature of microbial community structure in both natural and host environments; they enhance transmission and infectivity of pathogens and provide protection from human defense mechanisms and antibiotics. However, few natural products are known that impact biofilm formation or persistence for either environmental or pathogenic bacteria. Using the combination of a novel natural products library from the fish microbiome and an image-based screen for biofilm inhibition, we describe the identification of taurine-conjugated bile acids as inhibitors of biofilm formation against both Vibrio cholerae and Pseudomonas aeruginosa. Taurocholic acid (1) was isolated from the fermentation broth of the fish microbiome-derived strain of Rhodococcus erythropolis and identified using standard NMR and MS methods. Screening of the twelve predominant human steroidal bile acid components revealed that a subset of these compounds can inhibit biofilm formation, induce detachment of preformed biofilms under static conditions, and that these compounds display distinct structure-activity relationships against V. cholerae and P. aeruginosa. Our findings highlight the significance of distinct bile acid components in the regulation of biofilm formation and dispersion in two different clinically relevant bacterial pathogens, and suggest that the bile acids, which are endogenous mammalian metabolites used to solubilize dietary fats, may also play a role in maintaining host health against bacterial infection. PMID:26992172

  12. Physiological responses of bacteria in biofilms to disinfection.

    PubMed Central

    Yu, F P; McFeters, G A

    1994-01-01

    In situ enumeration methods using fluorescent probes and a radioisotope labelling technique were applied to evaluate physiological changes of Klebsiella pneumoniae within biofilms after disinfection treatment. Chlorine (0.25 mg of free chlorine per liter [pH 7.2]) and monochloramine (1 mg/liter [pH 9.0]) were employed as disinfectants in the study. Two fluorgenic compounds, 5-cyano-2,3-ditolyl tetrazolium chloride and rhodamine 123, and tritiated uridine incorporation were chosen for assessment of physiological activities. Results obtained by these methods were compared with those from the plate count and direct viable count methods. 5-Cyano-2,3-ditolyl tetrazolium chloride is an indicator of bacterial respiratory activity, rhodamine 123 is incorporated into bacteria in response to transmembrane potential, and the incorporation of uridine represents the global RNA turnover rate. The results acquired by these methods following disinfection exposure showed a range of responses and suggested different physiological reactions in biofilms exposed to chlorine and monochloramine. The direct viable count response and respiratory activity were affected more by disinfection than were the transmembrane potential and RNA turnover rate on the basis of comparable efficiency as evaluated by plate count enumeration. Information revealed by these approaches can provide different physiological insights that may be used in evaluating the efficacy of biofilm disinfection. PMID:8074525

  13. Mechanisms and regulation of surface interactions and biofilm formation in Agrobacterium

    PubMed Central

    Heindl, Jason E.; Wang, Yi; Heckel, Brynn C.; Mohari, Bitan; Feirer, Nathan; Fuqua, Clay

    2014-01-01

    For many pathogenic bacteria surface attachment is a required first step during host interactions. Attachment can proceed to invasion of host tissue or cells or to establishment of a multicellular bacterial community known as a biofilm. The transition from a unicellular, often motile, state to a sessile, multicellular, biofilm-associated state is one of the most important developmental decisions for bacteria. Agrobacterium tumefaciens genetically transforms plant cells by transfer and integration of a segment of plasmid-encoded transferred DNA (T-DNA) into the host genome, and has also been a valuable tool for plant geneticists. A. tumefaciens attaches to and forms a complex biofilm on a variety of biotic and abiotic substrates in vitro. Although rarely studied in situ, it is hypothesized that the biofilm state plays an important functional role in the ecology of this organism. Surface attachment, motility, and cell division are coordinated through a complex regulatory network that imparts an unexpected asymmetry to the A. tumefaciens life cycle. In this review, we describe the mechanisms by which A. tumefaciens associates with surfaces, and regulation of this process. We focus on the transition between flagellar-based motility and surface attachment, and on the composition, production, and secretion of multiple extracellular components that contribute to the biofilm matrix. Biofilm formation by A. tumefaciens is linked with virulence both mechanistically and through shared regulatory molecules. We detail our current understanding of these and other regulatory schemes, as well as the internal and external (environmental) cues mediating development of the biofilm state, including the second messenger cyclic-di-GMP, nutrient levels, and the role of the plant host in influencing attachment and biofilm formation. A. tumefaciens is an important model system contributing to our understanding of developmental transitions, bacterial cell biology, and biofilm formation. PMID:24834068

  14. Planktonic Replication Is Essential for Biofilm Formation by Legionella pneumophila in a Complex Medium under Static and Dynamic Flow Conditions

    PubMed Central

    Mampel, Jrg; Spirig, Thomas; Weber, Stefan S.; Haagensen, Janus A. J.; Molin, Sren; Hilbi, Hubert

    2006-01-01

    Legionella pneumophila persists for a long time in aquatic habitats, where the bacteria associate with biofilms and replicate within protozoan predators. While L. pneumophila serves as a paradigm for intracellular growth within protozoa, it is less clear whether the bacteria form or replicate within biofilms in the absence of protozoa. In this study, we analyzed surface adherence of and biofilm formation by L. pneumophila in a rich medium that supported axenic replication. Biofilm formation by the virulent L. pneumophila strain JR32 and by clinical and environmental isolates was analyzed by confocal microscopy and crystal violet staining. Strain JR32 formed biofilms on glass surfaces and upright polystyrene wells, as well as on pins of inverse microtiter plates, indicating that biofilm formation was not simply due to sedimentation of the bacteria. Biofilm formation by an L. pneumophila fliA mutant lacking the alternative sigma factor ?28 was reduced, which demonstrated that bacterial factors are required. Accumulation of biomass coincided with an increase in the optical density at 600 nm and ceased when the bacteria reached the stationary growth phase. L. pneumophila neither grew nor formed biofilms in the inverse system if the medium was exchanged twice a day. However, after addition of Acanthamoeba castellanii, the bacteria proliferated and adhered to surfaces. Sessile (surface-attached) and planktonic (free-swimming) L. pneumophila expressed ?-galactosidase activity to similar extents, and therefore, the observed lack of proliferation of surface-attached bacteria was not due to impaired protein synthesis or metabolic activity. Cocultivation of green fluorescent protein (GFP)- and DsRed-labeled L. pneumophila led to randomly interspersed cells on the substratum and in aggregates, and no sizeable patches of clonally growing bacteria were observed. Our findings indicate that biofilm formation by L. pneumophila in a rich medium is due to growth of planktonic bacteria rather than to growth of sessile bacteria. In agreement with this conclusion, GFP-labeled L. pneumophila initially adhered in a continuous-flow chamber system but detached over time; the detachment correlated with the flow rate, and there was no accumulation of biomass. Under these conditions, L. pneumophila persisted in biofilms formed by Empedobacter breve or Microbacterium sp. but not in biofilms formed by Klebsiella pneumoniae or other environmental bacteria, suggesting that specific interactions between the bacteria modulate adherence. PMID:16597995

  15. Sexual Biofilm Formation in Candida tropicalis Opaque Cells

    PubMed Central

    Jones, Stephen K.; Hirakawa, Matthew P.; Bennett, Richard J.

    2014-01-01

    Summary Candida albicans and Candida tropicalis are opportunistic fungal pathogens that can transition between white and opaque phenotypic states. White and opaque cells differ both morphologically and in their responses to environmental signals. In C. albicans, opaque cells respond to sexual pheromones by undergoing conjugation, while white cells are induced by pheromones to form sexual biofilms. Here, we show that sexual biofilm formation also occurs in C. tropicalis but, unlike C. albicans, biofilms are formed exclusively by opaque cells. C. tropicalis biofilm formation was dependent on the pheromone receptors Ste2 and Ste3, confirming the role of pheromone signaling in sexual biofilm development. Structural analysis of C. tropicalis sexual biofilms revealed stratified communities consisting of a basal layer of yeast cells and an upper layer of filamentous cells, together with an extracellular matrix. Transcriptional profiling showed that genes involved in pheromone signaling and conjugation were upregulated in sexual biofilms. Furthermore, FGR23, which encodes an agglutinin-like protein, was found to enhance both mating and sexual biofilm formation. Together, these studies reveal that C. tropicalis opaque cells form sexual biofilms with a complex architecture, and suggest a conserved role for sexual agglutinins in mediating mating, cell cohesion and biofilm formation. PMID:24612417

  16. An Expanded Regulatory Network Temporally Controls Candida albicans Biofilm Formation

    PubMed Central

    Fox, Emily P.; Bui, Catherine K.; Nett, Jeniel E.; Hartooni, Nairi; Mui, Michael M.; Andes, David R.; Nobile, Clarissa J.; Johnson, Alexander D.

    2015-01-01

    Summary Candida albicans biofilms are composed of highly adherent and densely arranged cells with properties distinct from those of free-floating (planktonic) cells. These biofilms are a significant medical problem because they commonly form on implanted medical devices, are drug resistant, and are difficult to remove. C. albicans biofilms are not static structures; rather they are dynamic and develop over time. Here we characterize gene expression in biofilms during their development, and by comparing them to multiple planktonic reference states, we identify patterns of gene expression relevant to biofilm formation. In particular, we document time-dependent changes in genes involved in adhesion and metabolism, both of which are at the core of biofilm development. Additionally, we identify three new regulators of biofilm formation, Flo8, Gal4, and Rfx2, which play distinct roles during biofilm development over time. Flo8 is required for biofilm formation at all timepoints, and Gal4 and Rfx2 are needed for proper biofilm formation at intermediate time points. PMID:25784162

  17. Prevention of Biofilm Formation and Removal of Existing Biofilms by Extracellular DNases of Campylobacter jejuni

    PubMed Central

    Brown, Helen L.; Reuter, Mark; Hanman, Kate; Betts, Roy P.; van Vliet, Arnoud H. M.

    2015-01-01

    The fastidious nature of the foodborne bacterial pathogen Campylobacter jejuni contrasts with its ability to survive in the food chain. The formation of biofilms, or the integration into existing biofilms by C. jejuni, is thought to contribute to food chain survival. As extracellular DNA (eDNA) has previously been proposed to play a role in C. jejuni biofilms, we have investigated the role of extracellular DNases (eDNases) produced by C. jejuni in biofilm formation. A search of 2791 C. jejuni genomes highlighted that almost half of C. jejuni genomes contains at least one eDNase gene, but only a minority of isolates contains two or three of these eDNase genes, such as C. jejuni strain RM1221 which contains the cje0256, cje0566 and cje1441 eDNase genes. Strain RM1221 did not form biofilms, whereas the eDNase-negative strains NCTC 11168 and 81116 did. Incubation of pre-formed biofilms of NCTC 11168 with live C. jejuni RM1221 or with spent medium from a RM1221 culture resulted in removal of the biofilm. Inactivation of the cje1441 eDNase gene in strain RM1221 restored biofilm formation, and made the mutant unable to degrade biofilms of strain NCTC 11168. Finally, C. jejuni strain RM1221 was able to degrade genomic DNA from C. jejuni NCTC 11168, 81116 and RM1221, whereas strain NCTC 11168 and the RM1221 cje1441 mutant were unable to do so. This was mirrored by an absence of eDNA in overnight cultures of C. jejuni RM1221. This suggests that the activity of eDNases in C. jejuni affects biofilm formation and is not conducive to a biofilm lifestyle. These eDNases do however have a potential role in controlling biofilm formation by C. jejuni strains in food chain relevant environments. PMID:25803828

  18. Pregrowth and Biofilm formation of Bacillus subtilis on Glass Studied via AFM, SEM and Optical Microsopy

    NASA Astrophysics Data System (ADS)

    Stutzman, Sydney; Otte, Michelle; Calabrese, Joseph; Senevirathne, Reshani; Senevirathne, Indrajith

    2014-03-01

    Lock Haven University of Pennsylvania - Research into surface adhesion properties and the selectivity of bacteria towards glass will provide a better understanding of biofilm formation and how this formation will in turn effect hospital and laboratory settings. Investigation was focused on quantifying the selectivity of non-pathogenic B. subtilis - on soda lime glass substrates. Standardized Corning 2947-75X25 microscope glass slides were used as the surface for bacterial attachment and facilitation of preliminary growth and formation of biofilms. Observations will be discussed both quantitatively and qualitatively. Structure morphology was investigated via Atomic Force Microscopy, Scanning Electron Microscopy and complemented with Optical Microscopy.

  19. Inhibitory effects of Lactobacillus fermentum on microbial growth and biofilm formation.

    PubMed

    Rybalchenko, Oxana V; Bondarenko, Viktor M; Orlova, Olga G; Markov, Alexander G; Amasheh, S

    2015-10-01

    Beneficial effects of Lactobacilli have been reported, and lactic bacteria are employed for conservation of foods. Therefore, the effects of a Lactobacillus fermentum strain were analyzed regarding inhibitory effects on staphylococci, Candida albicans and enterotoxigenic enterobacteria by transmission electron microscopy (TEM). TEM of bacterial biofilms was performed using cocultures of bacteriocin-producing L. fermentum 97 with different enterotoxigenic strains: Staphylococcus epidermidis expressing the ica gene responsible for biofilm formation, Staphylococcus aureus producing enterotoxin type A, Citrobacter freundii, Enterobacter cloaceae, Klebsiella oxytoca, Proteus mirabilis producing thermolabile and thermostable enterotoxins determined by elt or est genes, and Candida albicans. L. fermentum 97 changed morphological features and suppressed biofilm formation of staphylococci, enterotoxigenic enterobacteria and Candida albicans; a marked transition to resting states, a degradation of the cell walls and cytoplasm, and a disruption of mature bacterial biofilms were observed, the latter indicating efficiency even in the phase of higher cell density. PMID:26267163

  20. Exopolysaccharide Biosynthesis Enables Mature Biofilm Formation on Abiotic Surfaces by Herbaspirillum seropedicae

    PubMed Central

    Balsanelli, Eduardo; de Baura, Vlter Antonio; Pedrosa, Fbio de Oliveira; de Souza, Emanuel Maltempi; Monteiro, Rose Adele

    2014-01-01

    H. seropedicae associates endophytically and epiphytically with important poaceous crops and is capable of promoting their growth. The molecular mechanisms involved in plant colonization by this microrganism are not fully understood. Exopolysaccharides (EPS) are usually necessary for bacterial attachment to solid surfaces, to other bacteria, and to form biofilms. The role of H. seropedicae SmR1 exopolysaccharide in biofilm formation on both inert and plant substrates was assessed by characterization of a mutant in the espB gene which codes for a glucosyltransferase. The mutant strain was severely affected in EPS production and biofilm formation on glass wool. In contrast, the plant colonization capacity of the mutant strain was not altered when compared to the parental strain. The requirement of EPS for biofilm formation on inert surface was reinforced by the induction of eps genes in biofilms grown on glass and polypropylene. On the other hand, a strong repression of eps genes was observed in H. seropedicae cells adhered to maize roots. Our data suggest that H. seropedicae EPS is a structural component of mature biofilms, but this development stage of biofilm is not achieved during plant colonization. PMID:25310013

  1. Cinnamon bark oil and its components inhibit biofilm formation and toxin production.

    PubMed

    Kim, Yong-Guy; Lee, Jin-Hyung; Kim, Soon-Il; Baek, Kwang-Hyun; Lee, Jintae

    2015-02-16

    The long-term usage of antibiotics has resulted in the evolution of multidrug resistant bacteria, and pathogenic biofilms contribute to reduced susceptibility to antibiotics. In this study, 83 essential oils were initially screened for biofilm inhibition against Pseudomonas aeruginosa. Cinnamon bark oil and its main constituent cinnamaldehyde at 0.05% (v/v) markedly inhibited P. aeruginosa biofilm formation. Furthermore, cinnamon bark oil and eugenol decreased the production of pyocyanin and 2-heptyl-3-hydroxy-4(1H)-quinolone, the swarming motility, and the hemolytic activity of P. aeruginosa. Also, cinnamon bark oil, cinnamaldehyde, and eugenol at 0.01% (v/v) significantly decreased biofilm formation of enterohemorrhagic Escherichia coli O157:H7 (EHEC). Transcriptional analysis showed that cinnamon bark oil down-regulated curli genes and Shiga-like toxin gene stx2 in EHEC. In addition, biodegradable poly(lactic-co-glycolic acid) film incorporating biofilm inhibitors was fabricated and shown to provide efficient biofilm control on solid surfaces. This is the first report that cinnamon bark oil and its components, cinnamaldehyde and eugenol, reduce the production of pyocyanin and PQS, the swarming motility, and the hemolytic activity of P. aeruginosa, and inhibit EHEC biofilm formation. PMID:25500277

  2. Evaluating the Effect of Copper Nanoparticles in Inhibiting Pseudomonas aeruginosa and Listeria monocytogenes Biofilm Formation

    PubMed Central

    Ghasemian, Ehsan; Naghoni, Ali; Rahvar, Helya; Kialha, Mahsa; Tabaraie, Bahman

    2015-01-01

    Background: Biofilm formation is a major virulence factor in different bacteria. Biofilms allow bacteria to resist treatment with antibacterial agents. The biofilm formation on glass and steel surfaces, which are extremely useful surfaces in food industries and medical devices, has always had an important role in the distribution and transmission of infectious diseases. Objectives: In this study, the effect of coating glass and steel surfaces by copper nanoparticles (CuNPs) in inhibiting the biofilm formation by Listeria monocytogenes and Pseudomonas aeruginosa was examined. Materials and Methods: The minimal inhibitory concentrations (MICs) of synthesized CuNPs were measured against L. monocytogenes and P. aeruginosa by using the broth-dilution method. The cell-surface hydrophobicity of the selected bacteria was assessed using the bacterial adhesion to hydrocarbon (BATH) method. Also, the effect of the CuNP-coated surfaces on the biofilm formation of the selected bacteria was calculated via the surface assay. Results: The MICs for the CuNPs according to the broth-dilution method were ≤ 16 mg/L for L. monocytogenes and ≤ 32 mg/L for P. aeruginosa. The hydrophobicity of P. aeruginosa and L. monocytogenes was calculated as 74% and 67%, respectively. The results for the surface assay showed a significant decrease in bacterial attachment and colonization on the CuNP-covered surfaces. Conclusions: Our data demonstrated that the CuNPs inhibited bacterial growth and that the CuNP-coated surfaces decreased the microbial count and the microbial biofilm formation. Such CuNP-coated surfaces can be used in medical devices and food industries, although further studies in order to measure their level of toxicity would be necessary. PMID:26290685

  3. Beta- lactam antibiotics stimulate biofilm formation in non-typeable haemophilus influenzae by up-regulating carbohydrate metabolism.

    PubMed

    Wu, Siva; Li, Xiaojin; Gunawardana, Manjula; Maguire, Kathleen; Guerrero-Given, Debbie; Schaudinn, Christoph; Wang, Charles; Baum, Marc M; Webster, Paul

    2014-01-01

    Non-typeable Haemophilus influenzae (NTHi) is a common acute otitis media pathogen, with an incidence that is increased by previous antibiotic treatment. NTHi is also an emerging causative agent of other chronic infections in humans, some linked to morbidity, and all of which impose substantial treatment costs. In this study we explore the possibility that antibiotic exposure may stimulate biofilm formation by NTHi bacteria. We discovered that sub-inhibitory concentrations of beta-lactam antibiotic (i.e., amounts that partially inhibit bacterial growth) stimulated the biofilm-forming ability of NTHi strains, an effect that was strain and antibiotic dependent. When exposed to sub-inhibitory concentrations of beta-lactam antibiotics NTHi strains produced tightly packed biofilms with decreased numbers of culturable bacteria but increased biomass. The ratio of protein per unit weight of biofilm decreased as a result of antibiotic exposure. Antibiotic-stimulated biofilms had altered ultrastructure, and genes involved in glycogen production and transporter function were up regulated in response to antibiotic exposure. Down-regulated genes were linked to multiple metabolic processes but not those involved in stress response. Antibiotic-stimulated biofilm bacteria were more resistant to a lethal dose (10 g/mL) of cefuroxime. Our results suggest that beta-lactam antibiotic exposure may act as a signaling molecule that promotes transformation into the biofilm phenotype. Loss of viable bacteria, increase in biofilm biomass and decreased protein production coupled with a concomitant up-regulation of genes involved with glycogen production might result in a biofilm of sessile, metabolically inactive bacteria sustained by stored glycogen. These biofilms may protect surviving bacteria from subsequent antibiotic challenges, and act as a reservoir of viable bacteria once antibiotic exposure has ended. PMID:25007395

  4. Beta- Lactam Antibiotics Stimulate Biofilm Formation in Non-Typeable Haemophilus influenzae by Up-Regulating Carbohydrate Metabolism

    PubMed Central

    Wu, Siva; Li, Xiaojin; Gunawardana, Manjula; Maguire, Kathleen; Guerrero-Given, Debbie; Schaudinn, Christoph; Wang, Charles; Baum, Marc M.; Webster, Paul

    2014-01-01

    Non-typeable Haemophilus influenzae (NTHi) is a common acute otitis media pathogen, with an incidence that is increased by previous antibiotic treatment. NTHi is also an emerging causative agent of other chronic infections in humans, some linked to morbidity, and all of which impose substantial treatment costs. In this study we explore the possibility that antibiotic exposure may stimulate biofilm formation by NTHi bacteria. We discovered that sub-inhibitory concentrations of beta-lactam antibiotic (i.e., amounts that partially inhibit bacterial growth) stimulated the biofilm-forming ability of NTHi strains, an effect that was strain and antibiotic dependent. When exposed to sub-inhibitory concentrations of beta-lactam antibiotics NTHi strains produced tightly packed biofilms with decreased numbers of culturable bacteria but increased biomass. The ratio of protein per unit weight of biofilm decreased as a result of antibiotic exposure. Antibiotic-stimulated biofilms had altered ultrastructure, and genes involved in glycogen production and transporter function were up regulated in response to antibiotic exposure. Down-regulated genes were linked to multiple metabolic processes but not those involved in stress response. Antibiotic-stimulated biofilm bacteria were more resistant to a lethal dose (10 g/mL) of cefuroxime. Our results suggest that beta-lactam antibiotic exposure may act as a signaling molecule that promotes transformation into the biofilm phenotype. Loss of viable bacteria, increase in biofilm biomass and decreased protein production coupled with a concomitant up-regulation of genes involved with glycogen production might result in a biofilm of sessile, metabolically inactive bacteria sustained by stored glycogen. These biofilms may protect surviving bacteria from subsequent antibiotic challenges, and act as a reservoir of viable bacteria once antibiotic exposure has ended. PMID:25007395

  5. [Influence of poly-?-1-6-N-acetylglucosamine on biofilm formation and drug resistance of Acinetobacter baumannii].

    PubMed

    Guo, Haina; Xiang, Jun

    2015-02-01

    Acinetobacter baumannii has emerged as one of the leading bacteria for nosocomial infections, especially in burn wards and ICUs. The bacteria can easily form biofilm and readily attach to abiotic and biotic surfaces, resulting in persistent biofilm-mediated infections. Being surrounded by self-produced extracellular polymeric substance (EPS), the microorganisms in biofilm can acquire protective property against detrimental environment and their tolerance toward antibiotics is increased. Poly-?-1-6-N-acetylglucosamine (PNAG), the common constituent of EPS in Acinetobacter baumannii, acts as the key virulence factor and plays a crucial role in biofilm formation process. This review describes the properties and functions of the PNAG and its influence on biofilm formation and drug resistance of Acinetobacter baumannii. PMID:25876639

  6. Effects of Benzalkonium Chloride on Planktonic Growth and Biofilm Formation by Animal Bacterial Pathogens

    PubMed Central

    Ebrahimi, Azizollah; Hemati, Majid; Shabanpour, Ziba; Habibian Dehkordi, Saeed; Bahadoran, Shahab; Lotfalian, Sharareh; Khubani, Shahin

    2015-01-01

    Background: Resistance toward quaternary ammonium compounds (QACs) is widespread among a diverse range of microorganisms and is facilitated by several mechanisms such as biofilm formation. Objectives: In this study, the effects of benzalkonium chloride on planktonic growth and biofilm formation by some field isolates of animal bacterial pathogens were investigated. Materials and Methods: Forty clinical isolates of Escherichia coli, Salmonella serotypes, Staphylococcus aureus and Streptococcus agalactiae (10 isolates of each) were examined for effects of benzalkonium chloride on biofilm formation and planktonic growth using microtiter plates. For all the examined strains in the presence of benzalkonium chloride, biofilm development and planktonic growth were affected at the same concentrations of disinfectant. Results: The means of strains growth increase after the minimal inhibitory concentration (MIC) were significant in all the bacteria (except for E. coli in 1/32 and S. agalactiae in of 1/8 MIC). Biofilm formation increased with decrease of antiseptics concentration; a significant increase was found in all the samples. The most turbidity related to S. aureus and the least to Salmonella. Conclusions: Bacterial resistance against quaternary ammonium compounds is increasing which can increase the bacterial biofilm formation. PMID:25793094

  7. Targeted profiling of oral bacteria in human saliva and in vitro biofilms with quantitative real-time PCR.

    PubMed

    Price, R R; Viscount, H B; Stanley, M C; Leung, K-P

    2007-01-01

    An in vitro plaque model based on the use of human salivary bacteria and tooth-like surfaces was previously developed for studying the formation of oral biofilm and its use for pre-clinical testing of candidate antimicrobial or antiplaque agents. In this study, a quantitative Taqman PCR assay (QPCR) was developed to compare the bacterial compositions of in vitro biofilms to parent saliva samples, and to determine the relative contributions of different species in the formation of the oral biofilm. In addition, the growth inhibition of saliva-derived plaque was evaluated by chlorhexidine. With this assay, which consisted of primer/probe sets targeting either 16S rDNA sequences present in public databases or cloned ribosomal intergenic spacer region (ISR) sequences, 15 oral bacteria derived from saliva as well as those that were responsible for biofilm formation in an in vitro plaque model were rapidly identified and quantified. Among the target organisms were Actinobacillus actinomycetemcomitans, Eikenella corrodens, Fusobacterium nucleatum, Lactobacillus acidophilus, Micromonas micros, Porphyromonas gingivalis, Prevotella intermedia, Streptococcus mutans, Streptococcus sobrinus, Tannerella forsythensis, and Veillonella parvula. Primer and probe sets developed were both sensitive and specific. The relative profiles of a number of bacteria in 45-h-old biofilms were determined and, when compared to saliva samples, it was found that most of the bacteria identified in saliva also populated the in vitro plaque, including some anaerobes. Brief exposure of biofilms to chlorhexidine resulted in significant losses in viability. This new broad spectrum QPCR assay in combination with the in vitro plaque model will be of significant value in the quantitative study of the microbial composition of human saliva, saliva-derived plaque, and pre-clinical evaluation of potential antimicrobial and antiplaque molecules. PMID:17653931

  8. Effects of biofilm formation on the electrochemical behavior of AISI 304 SS in board machine environment

    SciTech Connect

    Carp, L.; Hakkarainen, T.; Raaska, L.

    1999-11-01

    The electrochemical behavior of and biofilm formation on AISI 304 stainless steel were studied in board machine environment with natural bacteria population. Open circuit potentials, redox-potential as well as different electrochemical measurements were performed. The biofilms formed were analyzed by microbial cultivation and by epifluorescence microscopy. The results of the measurements were compared with those performed both in sterilized white water and in artificial white water. The anodic polarization behavior of just immersed specimens was very similar in biotic (real), artificial and abiotic (sterilized) white water. Pitting initiated at very low potentials and continued to very negative values. The initiation of pitting became more difficult when the immersion time increased to 7 or 8 days in real, artificial or sterilized water. When the immersion time further increased, the pitting nucleated more easily in sterilized white water as well as in artificial white water than in biotic white water. In the laboratory equipment it was possible to maintain the biofilm already formed in the board mill, but the amount of sulfate reducing bacteria decreased and the amount of biofilm did not further increase. The composition and structure of the biofilm formed in laboratory differed from that formed in board mill conditions. The preliminary results indicate that the formation of biofilm in biotic white water rather inhibits than enhances the pitting corrosion of type AISI 304 stainless steel.

  9. Biofilms

    PubMed Central

    van Hoek, Monique L

    2013-01-01

    Our understanding of the virulence and pathogenesis of Francisella spp. has significantly advanced in recent years, including a new understanding that this organism can form biofilms. What is known so far about Francisella spp. biofilms is summarized here and future research questions are suggested. The molecular basis of biofilm production has begun to be studied, especially the role of extracellular carbohydrates and capsule, quorum sensing and two-component signaling systems. Further work has explored the contribution of amoebae, pili, outer-membrane vesicles, chitinases, and small molecules such as c-di-GMP to Francisella spp. biofilm formation. A role for Francisella spp. biofilm in feeding mosquito larvae has been suggested. As no strong role in virulence has been found yet, Francisella spp. biofilm formation is most likely a key mechanism for environmental survival and persistence. The significance and importance of Francisella spp.’s biofilm phenotype as a critical aspect of its microbial physiology is being developed. Areas for further studies include the potential role of Francisella spp. biofilms in the infection of mammalian hosts and virulence regulation. PMID:24225421

  10. Dynamics of biofilm formation during anaerobic digestion of organic waste.

    PubMed

    Langer, Susanne; Schropp, Daniel; Bengelsdorf, Frank R; Othman, Maazuza; Kazda, Marian

    2014-10-01

    Biofilm-based reactors are effectively used for wastewater treatment but are not common in biogas production. This study investigated biofilm dynamics on biofilm carriers incubated in batch biogas reactors at high and low organic loading rates for sludge from meat industry dissolved air flotation units. Biofilm formation and dynamics were studied using various microscopic techniques. Resulting micrographs were analysed for total cell numbers, thickness of biofilms, biofilm-covered surface area, and the area covered by extracellular polymeric substances (EPS). Cell numbers within biofilms (10(11)cellsml(-1)) were up to one order of magnitude higher compared to the numbers of cells in the fluid reactor content. Further, biofilm formation and structure mainly correlated with the numbers of microorganisms present in the fluid reactor content and the organic loading. At high organic loading (45kgVSm(-3)), the thickness of the continuous biofilm layer ranged from 5 to 160?m with an average of 51?m and a median of 26?m. Conversely, at lower organic loading (15kgVSm(-3)), only microcolonies were detectable. Those microcolonies increased in their frequency of occurrence during ongoing fermentation. Independently from the organic loading rate, biofilms were embedded completely in EPS within seven days. The maturation and maintenance of biofilms changed during the batch fermentation due to decreasing substrate availability. Concomitant, detachment of microorganisms within biofilms was observed simultaneously with the decrease of biogas formation. This study demonstrates that biofilms of high cell densities can enhance digestion of organic waste and have positive effects on biogas production. PMID:24342346

  11. Biofilm formation and dispersal and the transmission of human pathogens.

    PubMed

    Hall-Stoodley, Luanne; Stoodley, Paul

    2005-01-01

    Several pathogenic bacterial species that are found in the environment can form complex multicellular structures on surfaces known as biofilms. Pseudomonas aeruginosa, Vibrio cholerae and certain species of nontuberculous mycobacteria are examples of human pathogens that form biofilms in natural aquatic environments. We suggest that the dynamics of biofilm formation facilitates the transmission of pathogens by providing a stable protective environment and acting as a nidus for the dissemination of large numbers of microorganisms; both as detached biofilm clumps and by the fluid-driven dispersal of biofilm clusters along surfaces. We also suggest that emerging evidence indicates that biofilm formation conveys a selective advantage to certain pathogens by increasing their ability to persist under diverse environmental conditions. PMID:15639625

  12. Corrosion inhibition of stainless steel by a sulfate-reducing bacteria biofilm in seawater

    NASA Astrophysics Data System (ADS)

    Li, Fu-shao; An, Mao-zhong; Duan, Dong-xia

    2012-08-01

    Corrosion inhibition of stainless steel due to a sulfate-reducing bacteria (SRB) biofilm in seawater was studied. By atomic force microscopy, a layer of fish-scale-like biofilm was found to form as stainless steel coupons were exposed to the culture media with SRB, and this biofilm grew more and more compact. As a result, coupons' surface under the biofilm turned irregular less slowly than that exposed to the sterilized culture media. Then, physicoelectric characteristics of the electrode/biofilm/solution interface were investigated by electrochemical impedance spectroscopy (EIS), and the coverage of the biofilm as well as the relative irregularity of coupons' surface was also recorded by EIS spectra. Finally, anodic cyclic polarization results further demonstrated the protective property of the biofilm. Therefore, in estimation of SRB-implicated corrosion of stainless steel, not only the detrimental SRB metabolites but also the protective SRB biofilm as well should be taken into account.

  13. The biocidal effect of a novel synthesized gemini surfactant on environmental sulfidogenic bacteria: planktonic cells and biofilms.

    PubMed

    Labena, A; Hegazy, M A; Horn, H; Müller, E

    2015-02-01

    A cationic gemini surfactant was synthesized and characterized. The surfactant was successfully applied as a biocide against environmental sulfidogenic bacteria in the bulk phase (planktonic) and on the surface (biofilm). The activity of the synthesized surfactant was discussed based on the redox potential and the sulfide productivity in the bulk phase. The cultivated biofilm structure analysis and corrosion rate were estimated on the metal surface. The lowest metal corrosion rate was recognized at a concentration of 1mM with a metal corrosion inhibition efficiency of 95%. The synthesized gemini surfactant prevented the biofilm formation at a concentration of 0.1mM. The synthesized gemini surfactant displayed a broad spectrum antibacterial activity against Gram-positive and Gram-negative bacteria. PMID:25492209

  14. Complex conductivity response to microbial growth and biofilm formation on phenanthrene spiked medium

    NASA Astrophysics Data System (ADS)

    Albrecht, Remy; Gourry, Jean Christophe; Simonnot, Marie-Odile; Leyval, Corinne

    2011-11-01

    Several laboratory studies have recently demonstrated the utility of geophysical methods for the investigation of microbial-induced changes over contaminated sites. However, it remains difficult to distinguish the effects due to the new physical properties imparted by microbial processes, to bacterial growth, or to the development of bacterial biofilm. We chose to study the influence of biofilm formation on geophysical response using complex conductivity measurements (0.1-1000 Hz) in phenanthrene-contaminated media. Biotic assays were conducted with two phenanthrene (PHE) degrading bacterial strains: Burkholderia sp (NAH1), which produced biofilm and Stenophomonas maltophilia (MATE10), which did not, and an abiotic control. Results showed that bacterial densities for NAH1 and MATE10 strains continuously increased at the same rate during the experiment. However, the complex conductivity signature showed noticeable differences between the two bacteria, with a phase shift of 50 mrad at 4 Hz for NAH1, which produced biofilm. Biofilm volume was quantified by Scanning Confocal Laser Microscopy (SCLM). Significant correlations were established between phase shift decrease and biofilm volume for NAH1 assays. Results suggest that complex conductivity measurements, specifically phase shift, can be a useful indicator of biofilm formation inside the overall signal of microbial activity on contaminated sites.

  15. An 18 kDa scaffold protein is critical for Staphylococcus epidermidis biofilm formation.

    PubMed

    Decker, Rahel; Burdelski, Christoph; Zobiak, Melanie; Büttner, Henning; Franke, Gefion; Christner, Martin; Saß, Katharina; Zobiak, Bernd; Henke, Hanae A; Horswill, Alexander R; Bischoff, Markus; Bur, Stephanie; Hartmann, Torsten; Schaeffer, Carolyn R; Fey, Paul D; Rohde, Holger

    2015-03-01

    Virulence of the nosocomial pathogen Staphylococcus epidermidis is crucially linked to formation of adherent biofilms on artificial surfaces. Biofilm assembly is significantly fostered by production of a bacteria derived extracellular matrix. However, the matrix composition, spatial organization, and relevance of specific molecular interactions for integration of bacterial cells into the multilayered biofilm community are not fully understood. Here we report on the function of novel 18 kDa Small basic protein (Sbp) that was isolated from S. epidermidis biofilm matrix preparations by an affinity chromatographic approach. Sbp accumulates within the biofilm matrix, being preferentially deposited at the biofilm-substratum interface. Analysis of Sbp-negative S. epidermidis mutants demonstrated the importance of Sbp for sustained colonization of abiotic surfaces, but also epithelial cells. In addition, Sbp promotes assembly of S. epidermidis cell aggregates and establishment of multilayered biofilms by influencing polysaccharide intercellular-adhesin (PIA) and accumulation associated protein (Aap) mediated intercellular aggregation. While inactivation of Sbp indirectly resulted in reduced PIA-synthesis and biofilm formation, Sbp serves as an essential ligand during Aap domain-B mediated biofilm accumulation. Our data support the conclusion that Sbp serves as an S. epidermidis biofilm scaffold protein that significantly contributes to key steps of surface colonization. Sbp-negative S. epidermidis mutants showed no attenuated virulence in a mouse catheter infection model. Nevertheless, the high prevalence of sbp in commensal and invasive S. epidermidis populations suggests that Sbp plays a significant role as a co-factor during both multi-factorial commensal colonization and infection of artificial surfaces. PMID:25799153

  16. Formation of Propionibacterium acnes biofilms on orthopaedic biomaterials and their susceptibility to antimicrobials.

    PubMed

    Ramage, Gordon; Tunney, Michael M; Patrick, Sheila; Gorman, Sean P; Nixon, James R

    2003-08-01

    Failure to treat and eradicate prosthetic hip infection with systemic antibiotic regimens is usually due to the fact that the infection is associated with biofilm formation and that bacterial cells growing within a biofilm exhibit increased resistance to antimicrobial agents. In this in vitro study, we investigated the susceptibility of prosthetic hip Propionibacterium acnes and Staphylococcus spp. isolates growing within biofilms on polymethylmethacrylate (PMMA) bone cement to a range of antibiotics. All P. acnes isolates in the biofilm mode of growth demonstrated considerably greater resistance to cefamandole, ciprofloxacin and vancomycin. In contrast, only four of the eight P. acnes isolates demonstrated an increase in resistance to gentamicin. All ten Staphylococcus spp. isolates in the biofilm mode of growth exhibited large increases in resistance to gentamicin and cefamandole with eight of the ten isolates also exhibiting an increase in resistance to vancomycin. However, only three of the ten Staphylococcus spp. isolates exhibited an increase in resistance to ciprofloxacin. Biofilms were also formed on three different titanium alloys and on PMMA bone cement using P. acnes, Staphylococcus epidermidis and Staphylococcus aureus strains to determine if the underlying biomaterial surface had an effect on biofilm formation and the antimicrobial susceptibility of the bacteria growing within biofilms. Although differences in the rate at which the three strains adhered to the different biomaterials were apparent, no differences in biofilm antibiotic resistance between the biomaterials were observed. In the light of these results, it is important that the efficacy of other antibiotics against P. acnes and Staphylococcus spp. prosthetic hip isolates growing within biofilms on orthopaedic biomaterials be determined to ensure optimal treatment of orthopaedic implant infection. PMID:12763449

  17. Characterization of Mannheimia haemolytica biofilm formation in vitro.

    PubMed

    Boukahil, Ismail; Czuprynski, Charles J

    2015-01-30

    Mannheimia haemolytica is the primary bacterial agent in the bovine respiratory disease complex. It is thought that M. haemolytica colonizes the tonsillar crypts of cattle as a commensal and subsequently descends into the lungs to cause disease. Many bacterial species persist in the host as biofilms. There is limited information about the ability of M. haemolytica to form biofilms. The aim of this study was to develop an in vitro model for M. haemolytica biofilm formation. We found that M. haemolytica required at least 36 h to form robust biofilms on plastic in vitro when incubated in RPMI-1640 tissue culture medium at 37 °C, with maximal biofilm formation being evident at 48 h. Biofilm formation was inhibited by adding the monosaccharides d(+) galactose and d(+) mannose to the growth medium. Addition of antibodies to the M. haemolytica surface protein OmpA also reduced biofilm formation. Upon evaluating the macromolecules within the biofilm extracellular polymeric substance we found it contained 9.7 μg/cm(2) of protein, 0.81 μg/cm(2) of total carbohydrate, and 0.47 μg/cm(2) of extracellular DNA. Furthermore, proteinase K treatment significantly decreased biofilms (P<0.05) while α-amylase and micrococcal nuclease decreased biofilms to a lesser extent. M. haemolytica biofilm cells were more resistant than planktonic cells to the antibiotics florfenicol, gentamicin, and tulathromycin. These results provide evidence that M. haemolytica can form biofilms, which could contribute to its ability to persist as a commensal in the bovine upper respiratory tract. PMID:25480166

  18. Involvement of NADH Oxidase in Biofilm Formation in Streptococcus sanguinis

    PubMed Central

    Ge, Xiuchun; Shi, Xiaoli; Shi, Limei; Liu, Jinlin; Stone, Victoria; Kong, Fanxiang; Kitten, Todd; Xu, Ping

    2016-01-01

    Biofilms play important roles in microbial communities and are related to infectious diseases. Here, we report direct evidence that a bacterial nox gene encoding NADH oxidase is involved in biofilm formation. A dramatic reduction in biofilm formation was observed in a Streptococcus sanguinis nox mutant under anaerobic conditions without any decrease in growth. The membrane fluidity of the mutant bacterial cells was found to be decreased and the fatty acid composition altered, with increased palmitic acid and decreased stearic acid and vaccenic acid. Extracellular DNA of the mutant was reduced in abundance and bacterial competence was suppressed. Gene expression analysis in the mutant identified two genes with altered expression, gtfP and Idh, which were found to be related to biofilm formation through examination of their deletion mutants. NADH oxidase-related metabolic pathways were analyzed, further clarifying the function of this enzyme in biofilm formation. PMID:26950587

  19. Application of bacteriophages to reduce biofilms formed by hydrogen sulfide producing bacteria on surfaces in a rendering plant.

    PubMed

    Gong, Chao; Jiang, Xiuping

    2015-08-01

    Hydrogen sulfide producing bacteria (SPB) in raw animal by-products are likely to grow and form biofilms in the rendering processing environments, resulting in the release of harmful hydrogen sulfide (H2S) gas. The objective of this study was to reduce SPB biofilms formed on different surfaces typically found in rendering plants by applying a bacteriophage cocktail. Using a 96-well microplate method, we determined that 3 SPB strains of Citrobacter freundii and Hafnia alvei are strong biofilm formers. Application of 9 bacteriophages (10(7) PFU/mL) from families of Siphoviridae and Myoviridae resulted in a 33%-70% reduction of biofilm formation by each SPB strain. On stainless steel and plastic templates, phage treatment (10(8) PFU/mL) reduced the attached cells of a mixed SPB culture (no biofilm) by 2.3 and 2.7 log CFU/cm(2) within 6 h at 30 °C, respectively, as compared with 2 and 1.5 log CFU/cm(2) reductions of SPB biofilms within 6 h at 30 °C. Phage treatment was also applied to indigenous SPB biofilms formed on the environmental surface, stainless steel, high-density polyethylene plastic, and rubber templates in a rendering plant. With phage treatment (10(9) PFU/mL), SPB biofilms were reduced by 0.7-1.4, 0.3-0.6, and 0.2-0.6 log CFU/cm(2) in spring, summer, and fall trials, respectively. Our study demonstrated that bacteriophages could effectively reduce the selected SPB strains either attached to or in formed biofilms on various surfaces and could to some extent reduce the indigenous SPB biofilms on the surfaces in the rendering environment. PMID:26102989

  20. Controlled synthesis of the DSF cell-cell signal is required for biofilm formation and virulence in Xanthomonas campestris.

    PubMed

    Torres, Pablo S; Malamud, Florencia; Rigano, Luciano A; Russo, Daniela M; Marano, Mara Rosa; Castagnaro, Atilio P; Zorreguieta, Angeles; Bouarab, Kamal; Dow, John Maxwell; Vojnov, Adrin A

    2007-08-01

    Virulence of the black rot pathogen Xanthomonas campestris pv. campestris (Xcc) is regulated by cell-cell signalling involving the diffusible signal factor DSF. Synthesis and perception of DSF require products of genes within the rpf cluster (for regulation of pathogenicity factors). RpfF directs DSF synthesis whereas RpfC and RpfG are involved in DSF perception. Here we have examined the role of the rpf/DSF system in biofilm formation in minimal medium using confocal laser-scanning microscopy of GFP-labelled bacteria. Wild-type Xcc formed microcolonies that developed into a structured biofilm. In contrast, an rpfF mutant (DSF-minus) and an rpfC mutant (DSF overproducer) formed only unstructured arrangements of bacteria. A gumB mutant, defective in xanthan biosynthesis, was also unable to develop the typical wild-type biofilm. Mixed cultures of gumB and rpfF mutants formed a typical biofilm in vitro. In contrast, in mixed cultures the rpfC mutant prevented the formation of the structured biofilm by the wild-type and did not restore wild-type biofilm phenotypes to gumB or rpfF mutants. These effects on structured biofilm formation were correlated with growth and disease development by Xcc strains in Nicotiana benthamiana leaves. These findings suggest that DSF signalling is finely balanced during both biofilm formation and virulence. PMID:17635553

  1. Controlled synthesis of the DSF cellcell signal is required for biofilm formation and virulence in Xanthomonas campestris

    PubMed Central

    Torres, Pablo S; Malamud, Florencia; Rigano, Luciano A; Russo, Daniela M; Marano, Mara Rosa; Castagnaro, Atilio P; Zorreguieta, Angeles; Bouarab, Kamal; Dow, John Maxwell; Vojnov, Adrin A

    2007-01-01

    Virulence of the black rot pathogen Xanthomonas campestris pv. campestris (Xcc) is regulated by cellcell signalling involving the diffusible signal factor DSF. Synthesis and perception of DSF require products of genes within the rpf cluster (for regulation of pathogenicity factors). RpfF directs DSF synthesis whereas RpfC and RpfG are involved in DSF perception. Here we have examined the role of the rpf/DSF system in biofilm formation in minimal medium using confocal laser-scanning microscopy of GFP-labelled bacteria. Wild-type Xcc formed microcolonies that developed into a structured biofilm. In contrast, an rpfF mutant (DSF-minus) and an rpfC mutant (DSF overproducer) formed only unstructured arrangements of bacteria. A gumB mutant, defective in xanthan biosynthesis, was also unable to develop the typical wild-type biofilm. Mixed cultures of gumB and rpfF mutants formed a typical biofilm in vitro. In contrast, in mixed cultures the rpfC mutant prevented the formation of the structured biofilm by the wild-type and did not restore wild-type biofilm phenotypes to gumB or rpfF mutants. These effects on structured biofilm formation were correlated with growth and disease development by Xcc strains in Nicotiana benthamiana leaves. These findings suggest that DSF signalling is finely balanced during both biofilm formation and virulence. PMID:17635553

  2. Quorum-Quenching and Matrix-Degrading Enzymes in Multilayer Coatings Synergistically Prevent Bacterial Biofilm Formation on Urinary Catheters.

    PubMed

    Ivanova, Kristina; Fernandes, Margarida M; Francesko, Antonio; Mendoza, Ernest; Guezguez, Jamil; Burnet, Michael; Tzanov, Tzanko

    2015-12-16

    Bacteria often colonize in-dwelling medical devices and grow as complex biofilm communities of cells embedded in a self-produced extracellular polymeric matrix, which increases their resistance to antibiotics and the host immune system. During biofilm growth, bacterial cells cooperate through specific quorum-sensing (QS) signals. Taking advantage of this mechanism of biofilm formation, we hypothesized that interrupting the communication among bacteria and simultaneously degrading the extracellular matrix would inhibit biofilm growth. To this end, coatings composed of the enzymes acylase and α-amylase, able to degrade bacterial QS molecules and polysaccharides, respectively, were built on silicone urinary catheters using a layer-by-layer deposition technique. Multilayer coatings of either acylase or amylase alone suppressed the biofilm formation of corresponding Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus. Further assembly of both enzymes in hybrid nanocoatings resulted in stronger biofilm inhibition as a function of acylase or amylase position in the layers. Hybrid coatings, with the QS-signal-degrading acylase as outermost layer, demonstrated 30% higher antibiofilm efficiency against medically relevant Gram-negative bacteria compared to that of the other assemblies. These nanocoatings significantly reduced the occurrence of single-species (P. aeruginosa) and mixed-species (P. aeruginosa and Escherichia coli) biofilms on silicone catheters under both static and dynamic conditions. Moreover, in an in vivo animal model, the quorum quenching and matrix degrading enzyme assemblies delayed the biofilm growth up to 7 days. PMID:26593217

  3. Metabolic profiling of biofilm bacteria known to cause microbial influenced corrosion.

    PubMed

    Beale, D J; Morrison, P D; Key, C; Palombo, E A

    2014-01-01

    This study builds upon previous research that demonstrated the simplicity of obtaining metabolite profiles of bacteria in urban water networks, by using the metabolic profile of bacteria extracted from a reticulation pipe biofilm, which is known to cause microbial influenced corrosion (MIC). The extracellular metabolites of the isolated bacteria, and those bacteria in consortium, were analysed in isolation, and after exposure to low levels of copper. Applying chemometric analytical methodologies to the metabolomic data, we were able to better understand the profile of the isolated biofilm bacteria, which were differentiated according to their activity and copper exposure. It was found that the metabolic activity of the isolated bacteria and the bacteria in consortium varied according to the bacterium's ability to metabolise copper. This demonstrates the power of metabolomic techniques for the discrimination of water reticulation biofilms comprising similar bacteria in consortium, but undergoing different physico-chemical activities, such as corrosion and corrosion inhibition. PMID:24434961

  4. Streptococcus thermophilus Biofilm Formation: A Remnant Trait of Ancestral Commensal Life?

    PubMed Central

    Gautier, Céline; Renault, Pierre; Briandet, Romain; Guédon, Eric

    2015-01-01

    Microorganisms have a long history of use in food production and preservation. Their adaptation to food environments has profoundly modified their features, mainly through genomic flux. Streptococcus thermophilus, one of the most frequent starter culture organisms consumed daily by humans emerged recently from a commensal ancestor. As such, it is a useful model for genomic studies of bacterial domestication processes. Many streptococcal species form biofilms, a key feature of the major lifestyle of these bacteria in nature. However, few descriptions of S. thermophilus biofilms have been reported. An analysis of the ability of a representative collection of natural isolates to form biofilms revealed that S. thermophilus was a poor biofilm producer and that this characteristic was associated with an inability to attach firmly to surfaces. The identification of three biofilm-associated genes in the strain producing the most biofilms shed light on the reasons for the rarity of this trait in this species. These genes encode proteins involved in crucial stages of biofilm formation and are heterogeneously distributed between strains. One of the biofilm genes appears to have been acquired by horizontal transfer. The other two are located in loci presenting features of reductive evolution, and are absent from most of the strains analyzed. Their orthologs in commensal bacteria are involved in adhesion to host cells, suggesting that they are remnants of ancestral functions. The biofilm phenotype appears to be a commensal trait that has been lost during the genetic domestication of S. thermophilus, consistent with its adaptation to the milk environment and the selection of starter strains for dairy fermentations. PMID:26035177

  5. Coaggregation occurs amongst bacteria within and between biofilms in domestic showerheads.

    PubMed

    Vornhagen, Jay; Stevens, Michael; McCormick, David W; Dowd, Scot E; Eisenberg, Joseph N S; Boles, Blaise R; Rickard, Alexander H

    2013-01-01

    Showerheads support the development of multi-species biofilms that can be unsightly, produce malodor, and may harbor pathogens. The outer-surface spray-plates of many showerheads support visible biofilms that likely contain a mixture of bacteria from freshwater and potentially from human users. Coaggregation, a mechanism by which genetically distinct bacteria specifically recognize one another, may contribute to the retention and enrichment of different species within these biofilms. The aim of this work was to describe the bacterial composition of outer spray-plate biofilms of three domestic showerheads and to determine the intra- and inter-biofilm coaggregation ability of each culturable isolate. The bacterial composition of the three biofilms was determined by using bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP) and by culturing on R2A medium. An average of 31 genera per biofilm were identified using bTEFAP and a total of 30 isolates were cultured. Even though the microbial diversity of each showerhead biofilm differed, every cultured isolate was able to coaggregate with at least one other isolate from the same or different showerhead biofilm. Promiscuous coaggregating isolates belonged to the genera Brevundimonas, Micrococcus, and Lysobacter. This work suggests that coaggregation may be a common feature of showerhead biofilms. Characterization of the mechanisms mediating coaggregation, and the inter-species interactions they facilitate, may allow for novel strategies to inhibit biofilm development. PMID:23194413

  6. Effect of antibacterial dental adhesive on multispecies biofilms formation.

    PubMed

    Zhang, K; Wang, S; Zhou, X; Xu, H H K; Weir, M D; Ge, Y; Li, M; Wang, S; Li, Y; Xu, X; Zheng, L; Cheng, L

    2015-04-01

    Antibacterial adhesives have favorable prospects to inhibit biofilms and secondary caries. The objectives of this study were to investigate the antibacterial effect of dental adhesives containing dimethylaminododecyl methacrylate (DMADDM) on different bacteria in controlled multispecies biofilms and its regulating effect on development of biofilm for the first time. Antibacterial material was synthesized, and Streptococcus mutans, Streptococcus gordonii, and Streptococcus sanguinis were chosen to form multispecies biofilms. Lactic acid assay and pH measurement were conducted to study the acid production of controlled multispecies biofilms. Anthrone method and exopolysaccharide (EPS):bacteria volume ratio measured by confocal laser scanning microscopy were performed to determine the EPS production of biofilms. The colony-forming unit counts, scanning electron microscope imaging, and dead:live volume ratio decided by confocal laser scanning microscopy were used to study the biomass change of controlled multispecies biofilms. The TaqMan real-time polymerase chain reaction and fluorescent in situ hybridization imaging were used to study the proportion change in multispecies biofilms of different groups. The results showed that DMADDM-containing adhesive groups slowed the pH drop and decreased the lactic acid production noticeably, especially lactic acid production in the 5% DMADDM group, which decreased 10- to 30-fold compared with control group (P < 0.05). EPS was reduced significantly in 5% DMADDM group (P < 0.05). The DMADDM groups reduced the colony-forming unit counts significantly (P < 0.05) and had higher dead:live volume ratio in biofilms compared with control group (P < 0.05). The proportion of S. mutans decreased steadily in DMADDM-containing groups and continually increased in control group, and the biofilm had a more healthy development tendency after the regulation of DMADDM. In conclusion, the adhesives containing DMADDM had remarkable antimicrobial properties to serve as "bioactive" adhesive materials and revealed its potential value for antibiofilm and anticaries clinical applications. PMID:25715378

  7. In vivo biofilm formation on stainless steel bonded retainers during different oral health-care regimens.

    PubMed

    Jongsma, Marije A; van der Mei, Henny C; Atema-Smit, Jelly; Busscher, Henk J; Ren, Yijin

    2015-03-01

    Retention wires permanently bonded to the anterior teeth are used after orthodontic treatment to prevent the teeth from relapsing to pre-treatment positions. A disadvantage of bonded retainers is biofilm accumulation on the wires, which produces a higher incidence of gingival recession, increased pocket depth and bleeding on probing. This study compares in vivo biofilm formation on single-strand and multi-strand retention wires with different oral health-care regimens. Two-centimetre wires were placed in brackets that were bonded to the buccal side of the first molars and second premolars in the upper arches of 22 volunteers. Volunteers used a selected toothpaste with or without the additional use of a mouthrinse containing essential oils. Brushing was performed manually. Regimens were maintained for 1 week, after which the wires were removed and the oral biofilm was collected to quantify the number of organisms and their viability, determine the microbial composition and visualize the bacteria by electron microscopy. A 6-week washout period was employed between regimens. Biofilm formation was reduced on single-strand wires compared with multi-strand wires; bacteria were observed to adhere between the strands. The use of antibacterial toothpastes marginally reduced the amount of biofilm on both wire types, but significantly reduced the viability of the biofilm organisms. Additional use of the mouthrinse did not result in significant changes in biofilm amount or viability. However, major shifts in biofilm composition were induced by combining a stannous fluoride- or triclosan-containing toothpaste with the mouthrinse. These shifts can be tentatively attributed to small changes in bacterial cell surface hydrophobicity after the adsorption of the toothpaste components, which stimulate bacterial adhesion to the hydrophobic oil, as illustrated for a Streptococcus mutans strain. PMID:25572920

  8. Cell density-regulated recovery of starved biofilm populations of ammonia-oxidizing bacteria.

    PubMed

    Batchelor, S E; Cooper, M; Chhabra, S R; Glover, L A; Stewart, G S; Williams, P; Prosser, J I

    1997-06-01

    The speed of recovery of cell suspensions and biofilm populations of the ammonia oxidizer Nitrosomonas europaea, following starvation was determined. Stationary-phase cells, washed and resuspended in ammoniumfree inorganic medium, were starved for periods of up to 42 days, after which the medium was supplemented with ammonium and subsequent growth was monitored by measuring nitrite concentration changes. Cultures exhibited a lag phase prior to exponential nitrite production, which increased from 8.72 h (no starvation) to 153 h after starvation for 42 days. Biofilm populations of N. europaea colonizing sand or soil particles in continuous-flow, fixed column reactors were starved by continuous supply of ammonium-free medium. Following resupply of ammonium, starved biofilms exhibited no lag phase prior to nitrite production, even after starvation for 43.2 days, although there was evidence of cell loss during starvation. Biofilm formation will therefore provide a significant ecological advantage for ammonia oxidizers in natural environments in which the substrate supply is intermittent. Cell density-dependent phenomena in a number of gram-negative bacteria are mediated by N-acyl homoserine lactones (AHL), including N-(3-oxohexanoyl)-L-homoserine lactone (OHHL). Addition of both ammonium and OHHL to cell suspensions starved for 28 days decreased the lag phase in a concentration-dependent manner from 53.4 h to a minimum of 10.8 h. AHL production by N. europaea was detected by using a luxR-luxAB AHL reporter system. The results suggest that rapid recovery of high-density biofilm populations may be due to production and accumulation of OHHL to levels not possible in relatively low-density cell suspensions. PMID:9172348

  9. Inhibition of Pseudomonas aeruginosa biofilm formation on wound dressings.

    PubMed

    Brandenburg, Kenneth S; Calderon, Diego F; Kierski, Patricia R; Brown, Amanda L; Shah, Nihar M; Abbott, Nicholas L; Schurr, Michael J; Murphy, Christopher J; McAnulty, Jonathan F; Czuprynski, Charles J

    2015-11-12

    Chronic nonhealing skin wounds often contain bacterial biofilms that prevent normal wound healing and closure and present challenges to the use of conventional wound dressings. We investigated inhibition of Pseudomonas aeruginosa biofilm formation, a common pathogen of chronic skin wounds, on a commercially available biological wound dressing. Building on prior reports, we examined whether the amino acid tryptophan would inhibit P. aeruginosa biofilm formation on the three-dimensional surface of the biological dressing. Bacterial biomass and biofilm polysaccharides were quantified using crystal violet staining or an enzyme linked lectin, respectively. Bacterial cells and biofilm matrix adherent to the wound dressing were visualized through scanning electron microscopy. d-/l-tryptophan inhibited P. aeruginosa biofilm formation on the wound dressing in a dose dependent manner and was not directly cytotoxic to immortalized human keratinocytes although there was some reduction in cellular metabolism or enzymatic activity. More importantly, d-/l-tryptophan did not impair wound healing in a splinted skin wound murine model. Furthermore, wound closure was improved when d-/l-tryptophan treated wound dressing with P. aeruginosa biofilms were compared with untreated dressings. These findings indicate that tryptophan may prove useful for integration into wound dressings to inhibit biofilm formation and promote wound healing. PMID:26342168

  10. The relationship between biofilm formations and capsule in Haemophilus influenzae.

    PubMed

    Qin, Liang; Kida, Yutaka; Ishiwada, Naruhiko; Ohkusu, Kiyofumi; Kaji, Chiharu; Sakai, Yoshiro; Watanabe, Kiwao; Furumoto, Akitsugu; Ichinose, Akitoyo; Watanabe, Hiroshi

    2014-03-01

    To evaluate the biofilm formation of non-typeable Haemophilus influenzae (NTHi) and H. influenzae type b (Hib) clinical isolates, we conducted the following study. Serotyping and polymerase chain reaction were performed to identify ?-lactamase-negative ampicillin (ABPC)-susceptible (BLNAS), ?-lactamase-negative ABPC-resistant (BLNAR), TEM-1 type ?-lactamase-producing ABPC-resistant (BLPAR)-NTHi, and Hib. Biofilm formation was investigated by microtiter biofilm assay, as well as visually observation with a scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) in a continuous-flow chamber. As a result, totally 99 strains were investigated, and were classified into 4 groups which were 26 gBLNAS, 22 gBLNAR, 28 gBLPAR-NTHi and 23 Hib strains. The mean OD600 in the microtiter biofilm assay of gBLNAS, gBLNAR, gBLPAR-NTHi, and Hib strains were 0.57, 0.50, 0.34, and 0.08, respectively. NTHi strains were similar in terms of biofilm formations, which were observed by SEM and CLSM. Five Hib strains with the alternated type b cap loci showed significantly increased biofilm production than the other Hib strains. In conclusion, gBLNAS, gBLNAR, and gBLPAR-NTHi strains were more capable to produce biofilms compared to Hib strains. Our data suggested that resistant status may not be a key factor but capsule seemed to play an important role in H. influenzae biofilm formation. PMID:24560562

  11. Assessment and characterization of biofilm formation among human isolates of Streptococcus dysgalactiae subsp. equisimilis.

    PubMed

    Genteluci, Gabrielle Limeira; Silva, Ligia Guedes; Souza, Maria Clara; Glatthardt, Thas; de Mattos, Marcos Corra; Ejzemberg, Regina; Alviano, Celuta Sales; Figueiredo, Agnes Marie S; Ferreira-Carvalho, Bernadete Teixeira

    2015-12-01

    The capacity to form biofilm is considered a protective mechanism that allows the bacteria to survive and proliferate in hostile environments, facilitating the maintenance of the infectious process. Recently, biofilm has become a topic of interest in the study of the human pathogen group A Streptococcus (GAS). Although GAS has not been associated with infection on medical implants, the presence of microcolonies embedded in an extracellular matrix on infected tissues has been reported. Despite the similarity between GAS and Streptococcus dysgalactiae subspecies equisimilis (SDSE), there are no studies in the literature describing the production of biofilm by SDSE. In this work, we assessed and characterized biofilm development among SDSE human isolates of group C. The in vitro data showed that 59.3% of the 118 isolates tested were able to form acid-induced biofilm on glass, and 28% formed it on polystyrene surfaces. More importantly, biofilm was also formed in a foreign body model in mice. The biofilm structure was analyzed by confocal laser scanning microscopy, transmission electron microscopy, and scanning electron microscopy. Long fibrillar-like structures were observed by scanning electron microscopy. Additionally, the expression of a pilus associated gene of SDSE was increased for in vitro sessile cells compared with planktonics, and when sessile cells were collected from biofilms formed in the animal model compared with that of in vitro model. Results obtained from the immunofluorescence microscopy indicated the biofilm was immunogenic. Our data also suggested a role for proteins, exopolysaccharide and extracellular DNA in the formation and accumulation of biofilm by SDSE. PMID:26558847

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    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.

  13. 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

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

    PubMed

    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

  15. Small RNAs regulating biofilm formation and outer membrane homeostasis

    PubMed Central

    Van Puyvelde, Sandra; Steenackers, Hans P.; Vanderleyden, Jos

    2013-01-01

    Nowadays, the identification of small non-coding RNAs takes a prominent role in deciphering complex bacterial phenotypes. Evidences are given that the post-transcriptional layer of regulation mediated by sRNAs plays an important role in the formation of bacterial biofilms. These sRNAs exert their activity on various targets, be it directly or indirectly linked to biofilm formation. First, and best described, are the sRNAs that act in core regulatory pathways of biofilm formation, such as those regulating motility and matrix production. Second, overlaps between the regulation of biofilm formation and the outer membrane (OM) are becoming obvious. Additionally, different studies indicate that defects in the OM itself affect biofilm formation through this shared cascade, thereby forming a feedback mechanism. Interestingly, it is known that the OM itself is extensively regulated by different sRNAs. Third, biofilms are also linked to global metabolic changes. There is also evidence that metabolic pathways and the process of biofilm formation share sRNAs. PMID:23324602

  16. Sulfate reducing bacteria and their activities in oil sands process-affected water biofilm.

    PubMed

    Liu, Hong; Yu, Tong; Liu, Yang

    2015-12-01

    Biofilm reactors were constructed to grow stratified multispecies biofilm in oil sands process-affected water (OSPW) supplemented with growth medium. The development of sulfate reducing bacteria (SRB) within the biofilm and the biofilm treatment of OSPW were evaluated. The community structure and potential activity of SRB in the biofilm were investigated with H2S microsensor measurements, dsrB gene-based denaturing gradient gel electrophoresis (DGGE), and the real time quantitative polymerase chain reaction (qPCR). Multispecies biofilm with a thickness of 1000 ?m was successfully developed on engineered biocarriers. H2S production was observed in the deeper anoxic zone of the biofilm from around 750 ?m to 1000 ?m below the bulk water-biofilm interface, revealing sulfate reduction in the deeper zone of the stratified biofilm. The biofilm removed chemical oxygen demand (COD), sulfate, and nitrogen. The study expands current knowledge of biofilm treatment of OSPW and the function of anaerobic SRB in OSPW biofilm, and thus provides information for future bioreactor development in the reclamation of OSPW. PMID:26204047

  17. The effects of surface roughness of composite resin on biofilm formation of Streptococcus mutans in the presence of saliva.

    PubMed

    Park, J W; Song, C W; Jung, J H; Ahn, S J; Ferracane, J L

    2012-01-01

    The purpose of this study was to investigate the effects of surface roughness of resin composite on biofilm formation of Streptococcus mutans in the presence of saliva. To provide uniform surface roughness on composites, disks were prepared by curing composite against 400-grit silicon carbide paper (SR400), 800-grit silicon carbide paper (SR800), or a glass slide (SRGlass). The surface roughness was examined using confocal laser microscopy. For biofilm formation, S. mutans was grown for 24 hours with each disk in a biofilm medium with either glucose or sucrose in the presence of fluid-phase or surface-adsorbed saliva. The adherent bacteria were quantified via enumeration of the total viable counts of bacteria. Biofilms were examined using scanning electron microscopy. This study showed that SR400 had deeper and larger, but fewer depressions than SR800. Compared to SRGlass and SR800, biofilm formation was significantly increased on SR400. In addition, the differences in the effect of surface roughness on the amount of biofilm formation were not significantly influenced by either the presence of saliva or the carbohydrate source. Considering that similar differences in surface roughness were observed between SR400 and SR800 and between SR800 and SRGlass, this study suggests that surface topography (size and depth of depressions) may play a more important role than surface roughness in biofilm formation of S. mutans . PMID:22339385

  18. Toxin-Antitoxin Systems in Escherichia coli Influence Biofilm Formation through YjgK (TabA) and Fimbriae?

    PubMed Central

    Kim, Younghoon; Wang, Xiaoxue; Ma, Qun; Zhang, Xue-Song; Wood, Thomas K.

    2009-01-01

    The roles of toxin-antitoxin (TA) systems in bacteria have been debated. Here, the role of five TA systems in regard to biofilm development was investigated (listed as toxin/antitoxin: MazF/MazE, RelE/RelB, ChpB, YoeB/YefM, and YafQ/DinJ). Although these multiple TA systems were reported previously to not impact bacterial fitness, we found that deletion of the five TA systems decreased biofilm formation initially (8 h) on three different surfaces and then increased biofilm formation (24 h) by decreasing biofilm dispersal. Whole-transcriptome profiling revealed that the deletion of the five TA systems induced expression of a single gene, yjgK, which encodes an uncharacterized protein; quantitative real-time PCR (qRT-PCR) confirmed consistent induction of this gene (at 8, 15, and 24 h). Corroborating the complex phenotype seen upon deleting the TA systems, overexpression of YjgK decreased biofilm formation at 8 h and increased biofilm formation at 24 h; deletion of yjgK also affected biofilm formation in the expected manner by increasing biofilm formation after 8 h and decreasing biofilm formation after 24 h. In addition, YjgK significantly reduced biofilm dispersal. Whole-transcriptome profiling revealed YjgK represses fimbria genes at 8 h (corroborated by qRT-PCR and a yeast agglutination assay), which agrees with the decrease in biofilm formation upon deleting the five TA systems at 8 h, as well as that seen upon overexpressing YjgK. Sand column assays confirmed that deleting the five TA systems reduced cell attachment. Furthermore, deletion of each of the five toxins increased biofilm formation at 8 h, and overexpression of the five toxins repressed biofilm formation at 8 h, a result that is opposite that of deleting all five TA systems; this suggests that complex regulation occurs involving the antitoxins. Also, the ability of the global regulator Hha to reduce biofilm formation was dependent on the presence of these TA systems. Hence, we suggest that one role of TA systems is to influence biofilm formation. PMID:19060153

  19. An 18 kDa Scaffold Protein Is Critical for Staphylococcus epidermidis Biofilm Formation

    PubMed Central

    Zobiak, Melanie; Büttner, Henning; Franke, Gefion; Christner, Martin; Saß, Katharina; Zobiak, Bernd; Henke, Hanae A.; Horswill, Alexander R.; Bischoff, Markus; Bur, Stephanie; Hartmann, Torsten; Schaeffer, Carolyn R.; Fey, Paul D.; Rohde, Holger

    2015-01-01

    Virulence of the nosocomial pathogen Staphylococcus epidermidis is crucially linked to formation of adherent biofilms on artificial surfaces. Biofilm assembly is significantly fostered by production of a bacteria derived extracellular matrix. However, the matrix composition, spatial organization, and relevance of specific molecular interactions for integration of bacterial cells into the multilayered biofilm community are not fully understood. Here we report on the function of novel 18 kDa Small basic protein (Sbp) that was isolated from S. epidermidis biofilm matrix preparations by an affinity chromatographic approach. Sbp accumulates within the biofilm matrix, being preferentially deposited at the biofilm–substratum interface. Analysis of Sbp-negative S. epidermidis mutants demonstrated the importance of Sbp for sustained colonization of abiotic surfaces, but also epithelial cells. In addition, Sbp promotes assembly of S. epidermidis cell aggregates and establishment of multilayered biofilms by influencing polysaccharide intercellular-adhesin (PIA) and accumulation associated protein (Aap) mediated intercellular aggregation. While inactivation of Sbp indirectly resulted in reduced PIA-synthesis and biofilm formation, Sbp serves as an essential ligand during Aap domain-B mediated biofilm accumulation. Our data support the conclusion that Sbp serves as an S. epidermidis biofilm scaffold protein that significantly contributes to key steps of surface colonization. Sbp-negative S. epidermidis mutants showed no attenuated virulence in a mouse catheter infection model. Nevertheless, the high prevalence of sbp in commensal and invasive S. epidermidis populations suggests that Sbp plays a significant role as a co-factor during both multi-factorial commensal colonization and infection of artificial surfaces. PMID:25799153

  20. Biofilm formation by zygomycetes: quantification, structure and matrix composition.

    PubMed

    Singh, Rachna; Shivaprakash, M R; Chakrabarti, Arunaloke

    2011-09-01

    Most studies on fungal biofilms have focused on Candida in yeasts and Aspergillus in mycelial fungi. To the authors' knowledge, biofilm formation by zygomycetes has not been reported previously. In this study, the biofilm-forming capacity of Rhizopus oryzae, Lichtheimia corymbifera, Rhizomucor pusillus and Apophysomyces elegans was evaluated. At appropriate seeding spore densities, Rhp. oryzae (10? c.f.u. ml?, L. corymbifera (10? c.f.u. ml?) and Rhm. pusillus (10? c.f.u. ml?) produced highly intertwined, adherent structures on flat-bottomed polystyrene microtitre plates after 24 h at 37 C. The adhered fungal hyphae were encased in an extracellular matrix, as confirmed by phase-contrast and confocal microscopy. The thickness of Rhp. oryzae, L. corymbifera and Rhm. pusillus biofilms was 109.6710.02, 24223.07 and 1979.0 m (meansd), respectively. Biochemical characterization of the biofilm matrix indicated the presence of glucosamine, constituting 74.54-82.22?% of its dry weight, N-acetylglucosamine, glucose and proteins. Adherence and biofilm formation were not observed in A. elegans. Although A. elegans spores germinated at all three seeding densities tested (110?, 110? and 110? c.f.u. ml?), no significant difference was observed (P>0.05) between the A??? of wells inoculated with A. elegans and the cut-off A??? for biofilm detection. This study highlights the potential for biofilm formation by at least three medically important species of zygomycetes. PMID:21636650

  1. Biofilm formation of mucosa-associated methanoarchaeal strains

    PubMed Central

    Bang, Corinna; Ehlers, Claudia; Orell, Alvaro; Prasse, Daniela; Spinner, Marlene; Gorb, Stanislav N.; Albers, Sonja-Verena; Schmitz, Ruth A.

    2014-01-01

    Although in nature most microorganisms are known to occur predominantly in consortia or biofilms, data on archaeal biofilm formation are in general scarce. Here, the ability of three methanoarchaeal strains, Methanobrevibacter smithii and Methanosphaera stadtmanae, which form part of the human gut microbiota, and the Methanosarcina mazei strain Gö1 to grow on different surfaces and form biofilms was investigated. All three strains adhered to the substrate mica and grew predominantly as bilayers on its surface as demonstrated by confocal laser scanning microscopy analyses, though the formation of multi-layered biofilms of Methanosphaera stadtmanae and Methanobrevibacter smithii was observed as well. Stable biofilm formation was further confirmed by scanning electron microscopy analysis. Methanosarcina mazei and Methanobrevibacter smithii also formed multi-layered biofilms in uncoated plastic μ-dishesTM, which were very similar in morphology and reached a height of up to 40 μm. In contrast, biofilms formed by Methanosphaera stadtmanae reached only a height of 2 μm. Staining with the two lectins ConA and IB4 indicated that all three strains produced relatively low amounts of extracellular polysaccharides most likely containing glucose, mannose, and galactose. Taken together, this study provides the first evidence that methanoarchaea can develop and form biofilms on different substrates and thus, will contribute to our knowledge on the appearance and physiological role of Methanobrevibacter smithii and Methanosphaera stadtmanae in the human intestine. PMID:25071757

  2. Molecular analysis of long-term biofilm formation on PVC and cast iron surfaces in drinking water distribution system.

    PubMed

    Liu, Ruyin; Zhu, Junge; Yu, Zhisheng; Joshi, DevRaj; Zhang, Hongxun; Lin, Wenfang; Yang, Min

    2014-04-01

    To understand the impacts of different plumbing materials on long-term biofilm formation in water supply system, we analyzed microbial community compositions in the bulk water and biofilms on faucets with two different materials-polyvinyl chloride (PVC) and cast iron, which have been frequently used for more than10 years. Pyrosequencing was employed to describe both bacterial and eukaryotic microbial compositions. Bacterial communities in the bulk water and biofilm samples were significantly different from each other. Specific bacterial populations colonized on the surface of different materials. Hyphomicrobia and corrosion associated bacteria, such as Acidithiobacillus spp., Aquabacterium spp., Limnobacter thiooxidans, and Thiocapsa spp., were the most dominant bacteria identified in the PVC and cast iron biofilms, respectively, suggesting that bacterial colonization on the material surfaces was selective. Mycobacteria and Legionella spp. were common potential pathogenic bacteria occurred in the biofilm samples, but their abundance was different in the two biofilm bacterial communities. In contrast, the biofilm samples showed more similar eukaryotic communities than the bulk water. Notably, potential pathogenic fungi, i.e., Aspergillus spp. and Candida parapsilosis, occurred in similar abundance in both biofilms. These results indicated that microbial community, especially bacterial composition was remarkably affected by the different pipe materials (PVC and cast iron). PMID:25079417

  3. Effects of Norspermidine and Spermidine on Biofilm Formation by Potentially Pathogenic Escherichia coli and Salmonella enterica Wild-Type Strains

    PubMed Central

    Berg, Kristin; Vestby, Lene K.

    2015-01-01

    Polyamines are present in all living cells. In bacteria, polyamines are involved in a variety of functions, including biofilm formation, thus indicating that polyamines may have potential in the control of unwanted biofilm. In the present study, the effects of the polyamines norspermidine and spermidine on biofilms of 10 potentially pathogenic wild-type strains of Escherichia coli serotype O103:H2, Salmonella enterica subsp. enterica serovar Typhimurium, and S. enterica serovar Agona were investigated. We found that exogenously supplied norspermidine and spermidine did not mediate disassembly of preformed biofilm of any of the E. coli and S. enterica strains. However, the polyamines did affect biofilm production. Interestingly, the two species reacted differently to the polyamines. Both polyamines reduced the amount of biofilm formed by E. coli but tended to increase biofilm formation by S. enterica. Whether the effects observed were due to the polyamines specifically targeting biofilm formation, being toxic for the cells, or maybe a combination of the two, is not known. However, there were no indications that the effect was mediated through binding to exopolysaccharides, as earlier suggested for E. coli. Our results indicate that norspermidine and spermidine do not have potential as inhibitors of S. enterica biofilm. Furthermore, we found that the commercial polyamines used contributed to the higher pH of the test medium. Failure to acknowledge and control this important phenomenon may lead to misinterpretation of the results. PMID:25595767

  4. Culturable bacterial diversity from a feed water of a reverse osmosis system, evaluation of biofilm formation and biocontrol using phages.

    PubMed

    Belgini, D R B; Dias, R S; Siqueira, V M; Valadares, L A B; Albanese, J M; Souza, R S; Torres, A P R; Sousa, M P; Silva, C C; De Paula, S O; Oliveira, V M

    2014-10-01

    Biofilm formation on reverse osmosis (RO) systems represents a drawback in the application of this technology by different industries, including oil refineries. In RO systems the feed water maybe a source of microbial contamination and thus contributes for the formation of biofilm and consequent biofouling. In this study the planktonic culturable bacterial community was characterized from a feed water of a RO system and their capacities were evaluated to form biofilm in vitro. Bacterial motility and biofilm control were also analysed using phages. As results, diverse Protobacteria, Actinobacteria and Bacteroidetes were identified. Alphaproteobacteria was the predominant group and Brevundimonas, Pseudomonas and Mycobacterium the most abundant genera. Among the 30 isolates, 11 showed at least one type of motility and 11 were classified as good biofilm formers. Additionally, the influence of non-specific bacteriophage in the bacterial biofilms formed in vitro was investigated by action of phages enzymes or phage infection. The vB_AspP-UFV1 (Podoviridae) interfered in biofilm formation of most tested bacteria and may represent a good alternative in biofilm control. These findings provide important information about the bacterial community from the feed water of a RO system that may be used for the development of strategies for biofilm prevention and control in such systems. PMID:24980943

  5. Effective Prevention of Microbial Biofilm Formation on Medical Devices by Low-Energy Surface Acoustic Waves▿

    PubMed Central

    Hazan, Zadik; Zumeris, Jona; Jacob, Harold; Raskin, Hanan; Kratysh, Gera; Vishnia, Moshe; Dror, Naama; Barliya, Tilda; Mandel, Mathilda; Lavie, Gad

    2006-01-01

    Low-energy surface acoustic waves generated from electrically activated piezo elements are shown to effectively prevent microbial biofilm formation on indwelling medical devices. The development of biofilms by four different bacteria and Candida species is prevented when such elastic waves with amplitudes in the nanometer range are applied. Acoustic-wave-activated Foley catheters have all their surfaces vibrating with longitudinal and transversal dispersion vectors homogeneously surrounding the catheter surfaces. The acoustic waves at the surface are repulsive to bacteria and interfere with the docking and attachment of planktonic microorganisms to solid surfaces that constitute the initial phases of microbial biofilm development. FimH-mediated adhesion of uropathogenic Escherichia coli to guinea pig erythrocytes was prevented at power densities below thresholds that activate bacterial force sensor mechanisms. Elevated power densities dramatically enhanced red blood cell aggregation. We inserted Foley urinary catheters attached with elastic-wave-generating actuators into the urinary tracts of male rabbits. The treatment with the elastic acoustic waves maintained urine sterility for up to 9 days compared to 2 days in control catheterized animals. Scanning electron microscopy and bioburden analyses revealed diminished biofilm development on these catheters. The ability to prevent biofilm formation on indwelling devices and catheters can benefit the implanted medical device industry. PMID:16940055

  6. Effective prevention of microbial biofilm formation on medical devices by low-energy surface acoustic waves.

    PubMed

    Hazan, Zadik; Zumeris, Jona; Jacob, Harold; Raskin, Hanan; Kratysh, Gera; Vishnia, Moshe; Dror, Naama; Barliya, Tilda; Mandel, Mathilda; Lavie, Gad

    2006-12-01

    Low-energy surface acoustic waves generated from electrically activated piezo elements are shown to effectively prevent microbial biofilm formation on indwelling medical devices. The development of biofilms by four different bacteria and Candida species is prevented when such elastic waves with amplitudes in the nanometer range are applied. Acoustic-wave-activated Foley catheters have all their surfaces vibrating with longitudinal and transversal dispersion vectors homogeneously surrounding the catheter surfaces. The acoustic waves at the surface are repulsive to bacteria and interfere with the docking and attachment of planktonic microorganisms to solid surfaces that constitute the initial phases of microbial biofilm development. FimH-mediated adhesion of uropathogenic Escherichia coli to guinea pig erythrocytes was prevented at power densities below thresholds that activate bacterial force sensor mechanisms. Elevated power densities dramatically enhanced red blood cell aggregation. We inserted Foley urinary catheters attached with elastic-wave-generating actuators into the urinary tracts of male rabbits. The treatment with the elastic acoustic waves maintained urine sterility for up to 9 days compared to 2 days in control catheterized animals. Scanning electron microscopy and bioburden analyses revealed diminished biofilm development on these catheters. The ability to prevent biofilm formation on indwelling devices and catheters can benefit the implanted medical device industry. PMID:16940055

  7. In Lactobacillus pentosus, the olive brine adaptation genes are required for biofilm formation.

    PubMed

    Perpetuini, G; Pham-Hoang, B N; Scornec, H; Tofalo, R; Schirone, M; Suzzi, G; Cavin, J F; Waché, Y; Corsetti, A; Licandro-Seraut, H

    2016-01-01

    Lactobacillus pentosus is one of the few lactic acid bacteria (LAB) species capable of surviving in olive brine, and thus desirable during table olive fermentation. We have recently generated mutants of the efficient strain L. pentosus C11 by transposon mutagenesis and identified five mutants unable to survive and adapt to olive brine conditions. Since biofilm formation represents one of the main bacterial strategy to survive in stressful environments, in this study, the capacity of adhesion and formation of biofilm on olive skin was investigated for this strain and five derivative mutants which are interrupted in metabolic genes (enoA1 and gpi), and in genes of unknown function ("oba" genes). Confocal microscopy together with bacteria count revealed that the sessile state represented the prevailing L. pentosus C11 life-style during table olive fermentation. The characterization of cell surface properties showed that mutants present less hydrophobic and basic properties than the wild type (WT). In fact, their ability to adhere to both abiotic (polystyrene plates) and biotic (olive skin) surfaces was lower than that of the WT. Confocal microscopy revealed that mutants adhered sparsely to the olive skin instead of building a thin, multilayer biofilm. Moreover, RT-qPCR showed that the three genes enoA1, gpi and obaC were upregulated in the olive biofilm compared to the planktonic state. Thus enoA1, gpi and "oba" genes are necessary in L. pentosus to form an organized biofilm on the olive skin. PMID:26447789

  8. Quorum Sensing in Biofilms: Why Bacteria Behave the Way They Do

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacteria can attach to surfaces and form biofilms, which have a characteristic structure consisting of microcolonies enclosed in a hydrated matrix of microbially-produced proteins and polysaccharides. In this complex biofilm network, the cells act less as individual entities and more as a collectiv...

  9. Biofilm formation in spent nuclear fuel pools and bioremediation of radioactive water.

    PubMed

    Sarró, M Isabel; García, Ana M; Moreno, Diego A

    2005-09-01

    Microbiological studies of spent nuclear fuel pools at the Cofrentes Nuclear Power Plant (Valencia, Spain) were initiated to determine the microbial populations in the pools' water. Biofilm formation at the nuclear power plant facilities and the potential use of those microbial populations in the bioremediation of radioactive water were also studied. Biofilm formation was analyzed by immersing different austenitic stainless steel coupons (UNS S30400, UNS S30466, UNS S31600), as well as balls of stainless steel (UNS S44200) and titanium (99.9%) in a spent nuclear fuel pool (under static and dynamic conditions) for 34 months. Epifluorescence microscopy and scanning electron microscopy revealed that biofilm formed on the samples, in spite of the radioactive and oligotrophic conditions of the water. Based on standard culture methods and sequencing of 16S rDNA fragments, 57 bacteria belonging to alpha-, beta-, and gamma-Proteobacteria, Firmicutes and Actinobacteridae were identified in the biofilms. The radioactivity of the biofilm was measured using gamma-ray spectrometry, which revealed that biofilms were able to retain radionuclides, especially (60)Co. Using metallic materials to decontaminate radioactive water could become a new approach for bioremediation. PMID:16200501

  10. The Pseudomonas aeruginosa Type III Translocon Is Required for Biofilm Formation at the Epithelial Barrier

    PubMed Central

    Tran, Cindy S.; Rangel, Stephanie M.; Almblad, Henrik; Kierbel, Arlinet; Givskov, Michael; Tolker-Nielsen, Tim; Hauser, Alan R.; Engel, Joanne N.

    2014-01-01

    Clinical infections by Pseudomonas aeruginosa, a deadly Gram-negative, opportunistic pathogen of immunocompromised hosts, often involve the formation of antibiotic-resistant biofilms. Although biofilm formation has been extensively studied in vitro on glass or plastic surfaces, much less is known about biofilm formation at the epithelial barrier. We have previously shown that when added to the apical surface of polarized epithelial cells, P. aeruginosa rapidly forms cell-associated aggregates within 60 minutes of infection. By confocal microscopy we now show that cell-associated aggregates exhibit key characteristics of biofilms, including the presence of extracellular matrix and increased resistance to antibiotics compared to planktonic bacteria. Using isogenic mutants in the type III secretion system, we found that the translocon, but not the effectors themselves, were required for cell-associated aggregation on the surface of polarized epithelial cells and at early time points in a murine model of acute pneumonia. In contrast, the translocon was not required for aggregation on abiotic surfaces, suggesting a novel function for the type III secretion system during cell-associated aggregation. Supernatants from epithelial cells infected with wild-type bacteria or from cells treated with the pore-forming toxin streptolysin O could rescue aggregate formation in a type III secretion mutant, indicating that cell-associated aggregation requires one or more host cell factors. Our results suggest a previously unappreciated function for the type III translocon in the formation of P. aeruginosa biofilms at the epithelial barrier and demonstrate that biofilms may form at early time points of infection. PMID:25375398

  11. Inhibition of Serratia marcescens Smj-11 biofilm formation by Alcaligenes faecalis STN17 crude extract

    SciTech Connect

    Lutfi, Zainal; Ahmad, Asmat; Usup, Gires

    2014-09-03

    Serratia marcescens biofilms are formed when they are bound to surfaces in aqueous environments. S. marcescens utilizes N-acylhomoserine lactone (AHL) as its quorum sensing signal molecule. The accumulation of AHL indicates the bacteria to produce matrices to form biofilms. Prodigiosin (2-methyl-3-pentyl-6-methoxyprodigiosin), which causes red pigmentation in the colonies, are also produced when the AHL reaches a certain threshold. The Alcaligenes faecalis STN17 crude extract is believed to inhibit quorum sensing in the S. marcescens Smj-11 and, thus, impedes its biofilm formation ability. A. faecalis STN17 was grown in marine broth, and ethyl acetate extraction was carried out. The crude compound of A. faecalis STN17 was diluted at high concentration (0.2-6.4 mg/mL) and was taken to confirm anti-biofilm activity through the crystal violet method in 96-wells plate. Then, the crude extract underwent purification using simple solvents partitioning test to discern the respective compounds that had the anti-biofilm activity under the crystal violet method. The crystal violet test showed that the crude did have anti-biofilm activity on S. marcescens Smj-11, but did not kill the cells. This finding signifies that the suppression of biofilm formation in S. marcescens by A. faecalis STN17 has a strong correlation. The partitioning test showed that A. faecalis STN17 crude extract has several compounds and only the compound(s) in chloroform showed activities. In conclusion, the crude extract of A. faecalis STN17 has the ability to inhibit S. marcescens Smj-11 biofilm formation.

  12. Inhibition of Serratia marcescens Smj-11 biofilm formation by Alcaligenes faecalis STN17 crude extract

    NASA Astrophysics Data System (ADS)

    Lutfi, Zainal; Usup, Gires; Ahmad, Asmat

    2014-09-01

    Serratia marcescens biofilms are formed when they are bound to surfaces in aqueous environments. S. marcescens utilizes N-acylhomoserine lactone (AHL) as its quorum sensing signal molecule. The accumulation of AHL indicates the bacteria to produce matrices to form biofilms. Prodigiosin (2-methyl-3-pentyl-6-methoxyprodigiosin), which causes red pigmentation in the colonies, are also produced when the AHL reaches a certain threshold. The Alcaligenes faecalis STN17 crude extract is believed to inhibit quorum sensing in the S. marcescens Smj-11 and, thus, impedes its biofilm formation ability. A. faecalis STN17 was grown in marine broth, and ethyl acetate extraction was carried out. The crude compound of A. faecalis STN17 was diluted at high concentration (0.2-6.4 mg/mL) and was taken to confirm anti-biofilm activity through the crystal violet method in 96-wells plate. Then, the crude extract underwent purification using simple solvents partitioning test to discern the respective compounds that had the anti-biofilm activity under the crystal violet method. The crystal violet test showed that the crude did have anti-biofilm activity on S. marcescens Smj-11, but did not kill the cells. This finding signifies that the suppression of biofilm formation in S. marcescens by A. faecalis STN17 has a strong correlation. The partitioning test showed that A. faecalis STN17 crude extract has several compounds and only the compound(s) in chloroform showed activities. In conclusion, the crude extract of A. faecalis STN17 has the ability to inhibit S. marcescens Smj-11 biofilm formation.

  13. Spatial & Temporal Geophysical Monitoring of Microbial Growth and Biofilm Formation

    EPA Science Inventory

    Previous studies have examined the effect of biogenic gases and biomineralization on the acoustic properties of porous media. In this study, we investigated the spatiotemporal effect of microbial growth and biofilm formation on compressional waves and complex conductivity in sand...

  14. Bacterial Cyclic AMP-Phosphodiesterase Activity Coordinates Biofilm Formation

    PubMed Central

    Kalivoda, Eric J.; Brothers, Kimberly M.; Stella, Nicholas A.; Schmitt, Matthew J.; Shanks, Robert M. Q.

    2013-01-01

    Biofilm-related infections are a major contributor to human disease, and the capacity for surface attachment and biofilm formation are key attributes for the pathogenesis of microbes. Serratia marcescens type I fimbriae-dependent biofilms are coordinated by the adenylate cyclase, CyaA, and the cyclic 3′,5′-adenosine monophosphate (cAMP)-cAMP receptor protein (CRP) complex. This study uses S. marcescens as a model system to test the role of cAMP-phosphodiesterase activity in controlling biofilm formation. Herein we describe the characterization of a putative S. marcescens cAMP-phosphodiesterase gene (SMA3506), designated as cpdS, and demonstrated to be a functional cAMP-phosphodiesterase both in vitro and in vivo. Deletion of cpdS resulted in defective biofilm formation and reduced type I fimbriae production, whereas multicopy expression of cpdS conferred a type I fimbriae-dependent hyper-biofilm. Together, these results support a model in which bacterial cAMP-phosphodiesterase activity modulates biofilm formation. PMID:23923059

  15. Effect of Lactobacillus species on Streptococcus mutans biofilm formation.

    PubMed

    Ahmed, Ayaz; Dachang, Wu; Lei, Zhou; Jianjun, Liu; Juanjuan, Qiu; Yi, Xin

    2014-09-01

    Streptococcus mutans is the primary pathogen responsible for initiating dental caries and decay. The presence of sucrose, stimulates S. mutans to produce insoluble glucans to form oral biofilm also known as dental plaque to initiate caries lesion. The GtfB and LuxS genes of S. mutans are responsible for formation and maturation of biofilm. Lactobacillus species as probiotic can reduces the count of S. mutans. In this study effect of different Lactobacillus species against the formation of S. mutans biofilm was observed. Growing biofilm in the presence of sucrose was detected using 96 well microtiter plate crystal violet assay and biofilm formation by S. mutans in the presence of Lactobacillus was detected. Gene expression of biofilm forming genes (GtfB and LuxS) was quantified through Real-time PCR. All strains of Lactobacillus potently reduced the formation of S. mutans biofilm whereas Lactobacillus acidophilus reduced the genetic expression by 60-80%. Therefore, probiotic Lactobacillus species can be used as an alternative instead of antibiotics to decrease the chance of dental caries by reducing the count of S. mutans and their gene expression to maintain good oral health. PMID:25176247

  16. Alumina surfaces with nanoscale topography reduce attachment and biofilm formation by Escherichia coli and Listeria spp.

    PubMed

    Feng, Guoping; Cheng, Yifan; Wang, Shu-Yi; Hsu, Lillian C; Feliz, Yazmin; Borca-Tasciuc, Diana A; Worobo, Randy W; Moraru, Carmen I

    2014-01-01

    This work reports on a simple, robust and scientifically sound method to develop surfaces able to reduce microbial attachment and biofilm development, with possible applications in medicine, dentistry, food processing, or water treatment. Anodic surfaces with cylindrical nanopores 15 to 100nm in diameter were manufactured and incubated with Escherichia coli ATCC 25922 and Listeria innocua. Surfaces with 15 and 25nm pore diameters significantly repressed attachment and biofilm formation. Surface-bacteria interaction forces calculated using the extended Derjaguin Landau Verwey-Overbeek (XDLVO) theory indicate that reduction in attachment and biofilm formation is due to a synergy between electrostatic repulsion and surface effective free energy. An attachment study using E. coli K12 strains unable to express appendages also suggests that the small-pore surfaces may inhibit flagella-dependent attachment. These results can have immediate, far-reaching implications and commercial applications, with substantial benefits for human health and life. PMID:25427545

  17. 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, Mnica 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. PMID:23164974

  18. Biofilms suck: how bacteria beat the diffusion limit

    NASA Astrophysics Data System (ADS)

    Angelini, Thomas; Zhang, Wenbo; Zehnder, Steven; Breaux, Jolie

    2013-03-01

    Multicellular behavior in bacterial biofilms is intimately tied to the production of an extracellular polysaccharide (EPS) matrix that encases the cells and provides physical integrity to the colony as a whole. Recent work in Bacillus subtilis biofilms shows that a sudden increase in EPS production generates osmotic stresses that cause the biofilm to expand. Moreover, EPS production is triggered by a nutrient depletion gradient that develops in the biofilm due to diffusive mass transport limitations. These polymer physics based biofilm behaviors suggest that EPS production may have evolved in biofilms to beat the diffusion limit of nutrient transport into the colony, though no direct observation of nutrient transport has been observed previously. Here we measure the rate of nutrient transport into b. subtilis biofilms and find that when EPS production is up-regulated, the polymer sucks fluid into the colony with a characteristic time dependence like that of pressure driven flow. Preliminary data and analysis will be presented.

  19. Biofilm Formation Caused by Clinical Acinetobacter baumannii Isolates Is Associated with Overexpression of the AdeFGH Efflux Pump.

    PubMed

    He, Xinlong; Lu, Feng; Yuan, Fenglai; Jiang, Donglin; Zhao, Peng; Zhu, Jie; Cheng, Huali; Cao, Jun; Lu, Guozhong

    2015-08-01

    Chronic wound infections are associated with biofilm formation, which in turn has been correlated with drug resistance. However, the mechanism by which bacteria form biofilms in clinical environments is not clearly understood. This study was designed to investigate the biofilm formation potency of Acinetobacter baumannii and the potential association of biofilm formation with genes encoding efflux pumps, quorum-sensing regulators, and outer membrane proteins. A total of 48 clinically isolated A. baumannii strains, identified by enterobacterial repetitive intergenic consensus (ERIC)-PCR as types A-II, A-III, and A-IV, were analyzed. Three representative strains, which were designated A. baumannii ABR2, ABR11, and ABS17, were used to evaluate antimicrobial susceptibility, biofilm inducibility, and gene transcription (abaI, adeB, adeG, adeJ, carO, and ompA). A significant increase in the MICs of different classes of antibiotics was observed in the biofilm cells. The formation of a biofilm was significantly induced in all the representative strains exposed to levofloxacin. The levels of gene transcription varied between bacterial genotypes, antibiotics, and antibiotic concentrations. The upregulation of adeG correlated with biofilm induction. The consistent upregulation of adeG and abaI was detected in A-III-type A. baumannii in response to levofloxacin and meropenem (1/8 to 1/2× the MIC), conditions which resulted in the greatest extent of biofilm induction. This study demonstrates a potential role of the AdeFGH efflux pump in the synthesis and transport of autoinducer molecules during biofilm formation, suggesting a link between low-dose antimicrobial therapy and a high risk of biofilm infections caused by A. baumannii. This study provides useful information for the development of antibiofilm strategies. PMID:26033730

  20. Biofilm Formation Caused by Clinical Acinetobacter baumannii Isolates Is Associated with Overexpression of the AdeFGH Efflux Pump

    PubMed Central

    He, Xinlong; Lu, Feng; Yuan, Fenglai; Jiang, Donglin; Zhao, Peng; Zhu, Jie; Cheng, Huali

    2015-01-01

    Chronic wound infections are associated with biofilm formation, which in turn has been correlated with drug resistance. However, the mechanism by which bacteria form biofilms in clinical environments is not clearly understood. This study was designed to investigate the biofilm formation potency of Acinetobacter baumannii and the potential association of biofilm formation with genes encoding efflux pumps, quorum-sensing regulators, and outer membrane proteins. A total of 48 clinically isolated A. baumannii strains, identified by enterobacterial repetitive intergenic consensus (ERIC)-PCR as types A-II, A-III, and A-IV, were analyzed. Three representative strains, which were designated A. baumannii ABR2, ABR11, and ABS17, were used to evaluate antimicrobial susceptibility, biofilm inducibility, and gene transcription (abaI, adeB, adeG, adeJ, carO, and ompA). A significant increase in the MICs of different classes of antibiotics was observed in the biofilm cells. The formation of a biofilm was significantly induced in all the representative strains exposed to levofloxacin. The levels of gene transcription varied between bacterial genotypes, antibiotics, and antibiotic concentrations. The upregulation of adeG correlated with biofilm induction. The consistent upregulation of adeG and abaI was detected in A-III-type A. baumannii in response to levofloxacin and meropenem (1/8 to 1/2 the MIC), conditions which resulted in the greatest extent of biofilm induction. This study demonstrates a potential role of the AdeFGH efflux pump in the synthesis and transport of autoinducer molecules during biofilm formation, suggesting a link between low-dose antimicrobial therapy and a high risk of biofilm infections caused by A. baumannii. This study provides useful information for the development of antibiofilm strategies. PMID:26033730

  1. Blocking of Bacterial Biofilm Formation by a Fish Protein Coating?

    PubMed Central

    Vejborg, Rebecca Munk; Klemm, Per

    2008-01-01

    Bacterial biofilm formation on inert surfaces is a significant health and economic problem in a wide range of environmental, industrial, and medical areas. Bacterial adhesion is generally a prerequisite for this colonization process and, thus, represents an attractive target for the development of biofilm-preventive measures. We have previously found that the preconditioning of several different inert materials with an aqueous fish muscle extract, composed primarily of fish muscle ?-tropomyosin, significantly discourages bacterial attachment and adhesion to these surfaces. Here, this proteinaceous coating is characterized with regards to its biofilm-reducing properties by using a range of urinary tract infectious isolates with various pathogenic and adhesive properties. The antiadhesive coating significantly reduced or delayed biofilm formation by all these isolates under every condition examined. The biofilm-reducing activity did, however, vary depending on the substratum physicochemical characteristics and the environmental conditions studied. These data illustrate the importance of protein conditioning layers with respect to bacterial biofilm formation and suggest that antiadhesive proteins may offer an attractive measure for reducing or delaying biofilm-associated infections. PMID:18424549

  2. Unsaturated Fatty Acid, cis-2-Decenoic Acid, in Combination with Disinfectants or Antibiotics Removes Pre-Established Biofilms Formed by Food-Related Bacteria

    PubMed Central

    Sepehr, Shayesteh; Rahmani-Badi, Azadeh; Babaie-Naiej, Hamta; Soudi, Mohammad Reza

    2014-01-01

    Biofilm formation by food-related bacteria and food-related pathogenesis are significant problems in the food industry. Even though much disinfection and mechanical procedure exist for removal of biofilms, they may fail to eliminate pre-established biofilms. cis-2 decenoic acid (CDA), an unsaturated fatty acid messenger produced by Pseudomonas aeruginosa, is reportedly capable of inducing the dispersion of established biofilms by multiple types of microorganisms. However, whether CDA has potential to boost the actions of certain antimicrobials is unknown. Here, the activity of CDA as an inducer of pre-established biofilms dispersal, formed by four main food pathogens; Staphylococcus aureus, Bacillus cereus, Salmonella enterica and E. coli, was measured using both semi-batch and continuous cultures bioassays. To assess the ability of CDA combined biocides treatments to remove pre-established biofilms formed on stainless steel discs, CFU counts were performed for both treated and untreated cultures. Eradication of the biofilms by CDA combined antibiotics was evaluated using crystal violet staining. The effect of CDA combined treatments (antibiotics and disinfectants) on biofilm surface area and bacteria viability was evaluated using fluorescence microscopy, digital image analysis and LIVE/DEAD staining. MICs were also determined to assess the probable inhibitory effects of CDA combined treatments on the growth of tested microorganisms' planktonic cells. Treatment of pre-established biofilms with only 310 nM CDA resulted in at least two-fold increase in the number of planktonic cells in all cultures. While antibiotics or disinfectants alone exerted a trivial effect on CFU counts and percentage of surface area covered by the biofilms, combinational treatments with both 310 nM CDA and antibiotics or disinfectants led to approximate 80% reduction in biofilm biomass. These data suggests that combined treatments with CDA would pave the way toward developing new strategies to control biofilms with widespread applications in industry as well as medicine. PMID:25000301

  3. Flagella-Mediated Adhesion and Extracellular DNA Release Contribute to Biofilm Formation and Stress Tolerance of Campylobacter jejuni

    PubMed Central

    Svensson, Sarah L.; Pryjma, Mark; Gaynor, Erin C.

    2014-01-01

    Campylobacter jejuni is a leading cause of foodbourne gastroenteritis, despite fragile behaviour under standard laboratory conditions. In the environment, C. jejuni may survive within biofilms, which can impart resident bacteria with enhanced stress tolerance compared to their planktonic counterparts. While C. jejuni forms biofilms in vitro and in the wild, it had not been confirmed that this lifestyle confers stress tolerance. Moreover, little is understood about molecular mechanisms of biofilm formation in this pathogen. We previously found that a ΔcprS mutant, which carries a deletion in the sensor kinase of the CprRS two-component system, forms enhanced biofilms. Biofilms were also enhanced by the bile salt deoxycholate and contained extracellular DNA. Through more in-depth analysis of ΔcprS and WT under conditions that promote or inhibit biofilms, we sought to further define this lifestyle for C. jejuni. Epistasis experiments with ΔcprS and flagellar mutations (ΔflhA, ΔpflA) suggested that initiation is mediated by flagellum-mediated adherence, a process which was kinetically enhanced by motility. Lysis was also observed, especially under biofilm-enhancing conditions. Microscopy suggested adherence was followed by release of eDNA, which was required for biofilm maturation. Importantly, inhibiting biofilm formation by removal of eDNA with DNase decreased stress tolerance. This work suggests the biofilm lifestyle provides C. jejuni with resilience that has not been apparent from observation of planktonic bacteria during routine laboratory culture, and provides a framework for subsequent molecular studies of C. jejuni biofilms. PMID:25166748

  4. Effect of negative pressure on growth, secretion and biofilm formation of Staphylococcus aureus.

    PubMed

    Li, Tongtong; Wang, Guoqi; Yin, Peng; Li, Zhirui; Zhang, Licheng; Liu, Jianheng; Li, Ming; Zhang, Lihai; Han, Li; Tang, Peifu

    2015-10-01

    Negative pressure wound therapy (NPWT) has gained popularity in the management of contaminated wounds as an effective physical therapy, although its influence on the bacteria in the wounds remains unclear. In this study, we attempted to explore the effect of negative pressure conditions on Staphylococcus aureus, the most frequently isolated pathogen during wound infection. S. aureus was cultured in Luria-Bertani medium at subatmospheric pressure of -125 mmHg for 24 h, with the bacteria grown at ambient pressure as the control. The application of negative pressure was found to slow down the growth rate and inhibit biofilm development of S. aureus, which was confirmed by static biofilm assays. Furthermore, decreases in the total amount of virulence factors and biofilm components were observed, including α-hemolysin, extracellular adherence protein, polysaccharide intercellular adhesin and extracellular DNA. With quantitative RT-PCR analysis, we also revealed a significant inhibition in the transcription of virulence and regulatory genes related to wound infections and bacterial biofilms. Together, these findings indicated that negative pressure could inhibit the growth, virulence and biofilm formation of S. aureus. A topical subatmospheric pressure condition, such as NPWT, may be a potential antivirulence and antibiofilm strategy in the field of wound care. PMID:26272011

  5. Biofilm Dispersal

    PubMed Central

    2010-01-01

    Like all sessile organisms, surface-attached communities of bacteria known as biofilms must release and disperse cells into the environment to colonize new sites. For many pathogenic bacteria, biofilm dispersal plays an important role in the transmission of bacteria from environmental reservoirs to human hosts, in horizontal and vertical cross-host transmission, and in the exacerbation and spread of infection within a host. The molecular mechanisms of bacterial biofilm dispersal are only beginning to be elucidated. Biofilm dispersal is a promising area of research that may lead to the development of novel agents that inhibit biofilm formation or promote biofilm cell detachment. Such agents may be useful for the prevention and treatment of biofilms in a variety of industrial and clinical settings. This review describes the current status of research on biofilm dispersal, with an emphasis on studies aimed to characterize dispersal mechanisms, and to identify environmental cues and inter- and intracellular signals that regulate the dispersal process. The clinical implications of biofilm dispersal and the potential therapeutic applications of some of the most recent findings will also be discussed. PMID:20139339

  6. Modulation of Curli Assembly and Pellicle Biofilm Formation by Chemical and Protein Chaperones

    PubMed Central

    Andersson, Emma K.; Bengtsson, Christoffer; Evans, Margery L.; Chorell, Erik; Sellstedt, Magnus; Lindgren, Anders E.G.; Hufnagel, David A.; Bhattacharya, Moumita; Tessier, Peter M.; Wittung-Stafshede, Pernilla; Almqvist, Fredrik; Chapman, Matthew R.

    2014-01-01

    SUMMARY Enteric bacteria assemble functional amyloid fibers, curli, on their surfaces that share structural and biochemical properties with disease-associated amyloids. Here, we test rationally designed 2-pyridone compounds for their ability to alter amyloid formation of the major curli subunit CsgA. We identified several compounds that discourage CsgA amyloid formation and several compounds that accelerate CsgA amyloid formation. The ability of inhibitor compounds to stop growing CsgA fibers was compared to the same property of the CsgA chaperone, CsgE. CsgE blocked CsgA amyloid assembly and arrested polymerization when added to actively polymerizing fibers. Additionally, CsgE and the 2-pyridone inhibitors prevented biofilm formation by Escherichia coli at the air-liquid interface of a static culture. We demonstrate that curli amyloid assembly and curli-dependent biofilm formation can be modulated not only by protein chaperones, but also by chemical chaperones. PMID:24035282

  7. Small Regulatory RNAs in the Control of Motility and Biofilm Formation in E. coli and Salmonella

    PubMed Central

    Mika, Franziska; Hengge, Regine

    2013-01-01

    Biofilm formation in Escherichia coli and other enteric bacteria involves the inverse regulation of the synthesis of flagella and biofilm matrix components such as amyloid curli fibres, cellulose, colanic acid and poly-N-acetylglucosamine (PGA). Physiologically, these processes reflect the transition from growth to stationary phase. At the molecular level, they are tightly controlled by various sigma factors competing for RNA polymerase, a series of transcription factors acting in hierarchical regulatory cascades and several nucleotide messengers, including cyclic-di-GMP. In addition, a surprisingly large number of small regulatory RNAs (sRNAs) have been shown to directly or indirectly modulate motility and/or biofilm formation. This review aims at giving an overview of these sRNA regulators and their impact in biofilm formation in E. coli and Salmonella. Special emphasis will be put on sRNAs, that have known targets such as the mRNAs of the flagellar master regulator FlhDC, the stationary phase sigma factor σS (RpoS) and the key biofilm regulator CsgD that have recently been shown to act as major hubs for regulation by multiple sRNAs. PMID:23443158

  8. Integration of non-oral bacteria into in vitro oral biofilms

    PubMed Central

    Thurnheer, Thomas; Belibasakis, Georgios N

    2015-01-01

    Biofilms are polymicrobial communities that grow on surfaces in nature. Oral bacteria can spontaneously form biofilms on the surface of teeth, which may compromise the health of the teeth, or their surrounding (periodontal) tissues. While the oral bacteria exhibit high tropism for their specialized ecological niche, it is not clear if bacteria that are not part of the normal oral microbiota can efficiently colonize and grow within oral biofilms. By using an in vitro “supragingival” biofilm model of 6 oral species, this study aimed to investigate if 3 individual bacterial species that are not part of the normal oral microbiota (Eschericia coli, Staphylococcus aureus, Enterococcus faecails) and one not previously tested oral species (Aggregatibacter actinomycetemcomitans) can be incorporated into this established supragingival biofilm model. Staphylococcus aureus and A. actinomycetemcomitans were able to grow efficiently in the biofilm, without disrupting the growth of the remaining species. They localized in sparse small aggregates within the biofilm mass. Enterococcus faecalis and E. coli were both able to populate the biofilm at high numbers, and suppressed the growth of A. oris and S. mutants. Enterococcus faecalis was arranged in a chain-like conformation, whereas E. coli was densely and evenly spread throughout the biofilm mass. In conclusion, it is possible for selected species that are not part of the normal oral microbiota to be introduced into an oral biofilm, under the given experimental micro-environmental conditions. Moreover, the equilibrated incorporation of A. actinomycetemcomitans and S. aureus in this oral biofilm model could be a useful tool in the study of aggressive periodontitis and peri-implantitis, in which these organisms are involved, respectively. PMID:25483866

  9. Electrical spiking in bacterial biofilms.

    PubMed

    Masi, Elisa; Ciszak, Marzena; Santopolo, Luisa; Frascella, Arcangela; Giovannetti, Luciana; Marchi, Emmanuela; Viti, Carlo; Mancuso, Stefano

    2015-01-01

    In nature, biofilms are the most common form of bacterial growth. In biofilms, bacteria display coordinated behaviour to perform specific functions. Here, we investigated electrical signalling as a possible driver in biofilm sociobiology. Using a multi-electrode array system that enables high spatio-temporal resolution, we studied the electrical activity in two biofilm-forming strains and one non-biofilm-forming strain. The action potential rates monitored during biofilm-forming bacterial growth exhibited a one-peak maximum with a long tail, corresponding to the highest biofilm development. This peak was not observed for the non-biofilm-forming strain, demonstrating that the intensity of the electrical activity was not linearly related to the bacterial density, but was instead correlated with biofilm formation. Results obtained indicate that the analysis of the spatio-temporal electrical activity of bacteria during biofilm formation can open a new frontier in the study of the emergence of collective microbial behaviour. PMID:25392401

  10. Two quorum sensing systems control biofilm formation and virulence in members of the Burkholderia cepacia complex

    PubMed Central

    Suppiger, Angela; Schmid, Nadine; Aguilar, Claudio; Pessi, Gabriella; Eberl, Leo

    2013-01-01

    The Burkholderia cepacia complex (Bcc) consists of 17 closely related species that are problematic opportunistic bacterial pathogens for cystic fibrosis patients and immunocompromised individuals. These bacteria are capable of utilizing two different chemical languages: N-acyl homoserine lactones (AHLs) and cis-2-unsaturated fatty acids. Here we summarize the current knowledge of the underlying molecular architectures of these communication systems, showing how they are interlinked and discussing how they regulate overlapping as well as specific sets of genes. A particular focus is laid on the role of these signaling systems in the formation of biofilms, which are believed to be highly important for chronic infections. We review genes that have been implicated in the sessile lifestyle of this group of bacteria. The new emerging role of the intracellular second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) as a downstream regulator of the fatty acid signaling cascade and as a key factor in biofilm formation is also discussed. PMID:23799665

  11. Biofilm formation and control in a simulated spacecraft water system - Interim results

    NASA Technical Reports Server (NTRS)

    Schultz, John R.; Taylor, Robert D.; Flanagan, David T.; Gibbons, Randall E.; Brown, Harlan D.; Sauer, Richard L.

    1989-01-01

    The ability of iodine to control microbial contamination and biofilm formation in spacecraft water distribution systems is studied using two stainless steel water subsystems. One subsystem has an iodine level of 2.5 mg/L maintained by an iodinated ion-exchange resin. The other subsystem has no iodine added. Stainless steel coupons are removed from each system to monitor biofilm formation. Results from the first six months of operation indicate that 2.5 mg/L of iodine has limited the number of viable bacteria that can be recovered from the iodinated subsystem. Epifluorescence microscopy of the coupons taken from this subsystem, however, indicates some evidence of microbial colonization after 15 weeks of operation. Numerous bacteria have been continually removed from both the water samples and the coupons taken from the noniodinated subsystem after only 3 weeks of operation.

  12. Regulation of biofilm formation by BpfA, BpfD, and BpfG in Shewanella oneidensis

    PubMed Central

    Zhou, Guangqi; Yuan, Jie; Gao, Haichun

    2015-01-01

    Bacteria switch between two distinct life styles planktonic (free living) and biofilm forming in keeping with their ever-changing environment. Such switch involves sophisticated signaling and tight regulation, which provides a fascinating portal for studying gene function and orchestrated protein interactions. In this work, we investigated the molecular mechanism underlying biofilm formation in Shewanella oneidensis MR-1, an environmentally important model bacterium renowned for respiratory diversities, and uncovered a gene cluster coding for seven proteins involved in this process. The three key proteins, BpfA, BpfG, and BpfD, were studied in detail for the first time. BpfA directly participates in biofilm formation as extracellular glue BpfG is not only indispensable for BpfA export during biofilm forming but also functions to turn BpfA into active form for biofilm dispersing. BpfD regulates biofilm development by interacting with both BpfA and BpfG, likely in response to signal molecule c-di-GMP. In addition, we found that 1:1 stoichiometry between BpfD and BpfG is critical for biofilm formation. Furthermore, we demonstrated that a biofilm over-producing phenotype can be induced by C116S mutation but not loss of BpfG. PMID:26300859

  13. Photodynamic inactivation of antibiotic-resistant bacteria and biofilms by hematoporphyrin monomethyl ether.

    PubMed

    Liu, Chengcheng; Hu, Min; Ma, Dandan; Lei, Jin'e; Xu, Jiru

    2016-02-01

    The worldwide increase in bacterial antibiotic resistance has led to a search for alternative antibacterial therapies. A promising approach to killing antibiotic-resistant bacteria is photodynamic antimicrobial chemotherapy, which uses light in combination with a photosensitizer to induce a phototoxic reaction. We evaluated the photodynamic inactivation (PDI) efficiency of hematoporphyrin monomethyl ether (HMME) on antibiotic-resistant bacteria and biofilms. HMME exhibited no significant dark toxicity and provided dose-dependent inactivation of antibiotic-resistant bacteria and biofilms. After incubation with 100-μM HMME and irradiation with 72-J cm(-2) white light, 4.19-7.59 log10 reductions in survival were achieved in planktonic suspension. Antibiotic-resistant strains were as susceptible to PDI in biofilms as in planktonic suspensions, but the inactivation of bacterial cells in biofilms was attenuated. In addition, gram-positive bacterial strains and biofilms were more susceptible than gram-negative strains and biofilms to the PDI effect of HMME. Thus, HMME is a promising photosensitizer for the treatment of infectious diseases caused by antibiotic-resistant bacteria, especially gram-positive bacteria. PMID:26719055

  14. Oral Streptococci Biofilm Formation on Different Implant Surface Topographies

    PubMed Central

    Pita, Pedro Paulo Cardoso; Rodrigues, Jos Augusto; Ota-Tsuzuki, Claudia; Miato, Tatiane Ferreira; Zenobio, Elton G.; Giro, Gabriela; Figueiredo, Luciene C.; Gonalves, Cristiane; Gehrke, Sergio A.; Cassoni, Alessandra; Shibli, Jamil Awad

    2015-01-01

    The establishment of the subgingival microbiota is dependent on successive colonization of the implant surface by bacterial species. Different implant surface topographies could influence the bacterial adsorption and therefore jeopardize the implant survival. This study evaluated the biofilm formation capacity of five oral streptococci species on two titanium surface topographies. In vitro biofilm formation was induced on 30 titanium discs divided in two groups: sandblasted acid-etched (SAE- n = 15) and as-machined (M- n = 15) surface. The specimens were immersed in sterilized whole human unstimulated saliva and then in fresh bacterial culture with five oral streptococci species: Streptococcus sanguinis, Streptococcus salivarius, Streptococcus mutans, Streptococcus sobrinus, and Streptococcus cricetus. The specimens were fixed and stained and the adsorbed dye was measured. Surface characterization was performed by atomic force and scanning electron microscopy. Surface and microbiologic data were analyzed by Student's t-test and two-way ANOVA, respectively (P < 0.05). S. cricetus, S. mutans, and S. sobrinus exhibited higher biofilm formation and no differences were observed between surfaces analyzed within each species (P > 0.05). S. sanguinis exhibited similar behavior to form biofilm on both implant surface topographies, while S. salivarius showed the lowest ability to form biofilm. It was concluded that biofilm formation on titanium surfaces depends on surface topography and species involved. PMID:26273590

  15. A small-molecule norspermidine and norspermidine-hosting polyelectrolyte coatings inhibit biofilm formation by multi-species wastewater culture.

    PubMed

    Si, Xiurong; Quan, Xiangchun; Wu, Yachuan

    2015-12-01

    Norspermidine is a potent and non-bactericidal small-molecule inhibitor of biofilm growth. In this study, impacts of norspermidine on biofilm control and existing biofilm dispersal by a mixed culture from wastewater treatment systems were investigated. A surface-mediated releasing approach for prevention of bacterial biofilm formation was established via encapsulating norspermidine into polyelectrolyte multilayer coatings. Results showed that the presence of norspermidine (500-1000 μM) in medium remarkably prevented biofilm formation. Norspermidine was also effective in disassembling pre-formed biofilms. Norspermidine-containing multilayer coatings were successfully fabricated on glass slides via layer-by-layer deposition in polyethylenimine (PEI) and poly(acrylic acid) (PAA) solution. This coating exhibited a high anti-biofilm property against a mixed culture and three pure strains (Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli). The loading amount and space distribution of norspermidine in the multilayer coating were key factors influencing its anti-biofilm efficacy. The polymer coating with norspermidine loaded in each bilayer (each-layer-type) exhibited better anti-biofilm efficacy than the bottom-type and the top-type coating, which showed a stable biofilm inhibition rate of about 60 % even after 5-day leaching in aqueous solution. Norspermidine could retard bacterial adhesion and destruct biofilm matrix by reducing exopolysaccharides and extracellular DNA (eDNA) associated with bacteria instead of growth inhibition. Norspermidine and the norspermidine-hosting coatings in this study offer a great potential for the control of biofilms in the settings of water purification and wastewater treatment systems, which shows the advantage of broad spectrum and less risk of evolved bacterial resistance compared to conventional microbicidal agents (e.g., antibiotics). PMID:26350146

  16. Biofilms and antimicrobial resistance.

    PubMed

    Patel, Robin

    2005-08-01

    The pathogenesis of many orthopaedic infections is related to the presence of microorganisms in biofilms. I examine the emerging understanding of the mechanisms of biofilm-associated antimicrobial resistance. Biofilm-associated resistance to antimicrobial agents begins at the attachment phase and increases as the biofilm ages. A variety of reasons for the increased antimicrobial resistance of microorganisms in biofilms have been postulated and investigated. Although bacteria in biofilms are surrounded by an extracellular matrix that might physically restrict the diffusion of antimicrobial agents, this does not seem to be a predominant mechanism of biofilm-associated antimicrobial resistance. Nutrient and oxygen depletion within the biofilm cause some bacteria to enter a nongrowing (ie, stationary) state, in which they are less susceptible to growth-dependent antimicrobial killing. A subpopulation of bacteria might differentiate into a phenotypically resistant state. Finally, some organisms in biofilms have been shown to express biofilm-specific antimicrobial resistance genes that are not required for biofilm formation. Overall, the mechanism of biofilm-associated antimicrobial resistance seems to be multifactorial and may vary from organism to organism. Techniques that address biofilm susceptibility testing to antimicrobial agents may be necessary before antimicrobial regimens for orthopaedic prosthetic device-associated infections can be appropriately defined in research and clinical settings. Finally, a variety of approaches are being defined to overcome biofilm-associated antimicrobial resistance. PMID:16056024

  17. Cold plasma inactivation of internalised bacteria and biofilms for Salmonella enterica serovar Typhimurium, Listeria monocytogenes and Escherichia coli.

    PubMed

    Ziuzina, Dana; Han, Lu; Cullen, Patrick J; Bourke, Paula

    2015-10-01

    Microbial biofilms and bacteria internalised in produce tissue may reduce the effectiveness of decontamination methods. In this study, the inactivation efficacy of in-package atmospheric cold plasma (ACP) afterglow was investigated against Salmonella Typhimurium, Listeria monocytogenes and Escherichia coli in the forms of planktonic cultures, biofilms formed on lettuce and associated bacteria internalised in lettuce tissue. Prepared lettuce broth (3%) was inoculated with bacteria resulting in a final concentration of ~7.0 log10 CFU/ml. For biofilm formation and internalisation, lettuce pieces (5 5 cm) were dip-inoculated in bacterial suspension of ~7.0 log10 CFU/ml for 2 h and further incubated for 0, 24 and 48 h at either 4 C or room temperature (~22 C) in combination with light/dark photoperiod or at 4 C under dark conditions. Inoculated samples were sealed inside a rigid polypropylene container and indirectly exposed (i.e. placed outside plasma discharge) to a high voltage (80 kVRMS) air ACP with subsequent storage for 24 h at 4 C. ACP treatment for 30s reduced planktonic populations of Salmonella, L. monocytogenes and E. coli suspended in lettuce broth to undetectable levels. Depending on storage conditions, bacterial type and age of biofilm, 300 s of treatment resulted in reduction of biofilm populations on lettuce by a maximum of 5 log10 CFU/sample. Scanning electron and confocal laser microscopy pointed to the incidence of bacterial internalisation and biofilm formation, which influenced the inactivation efficacy of ACP. Measured intracellular reactive oxygen species (ROS) revealed that the presence of organic matter in the bacterial suspension might present a protective effect against the action of ROS on bacterial cells. This study demonstrated that high voltage in-package ACP could be a potential technology to overcome bacterial challenges associated with food produce. However, the existence of biofilms and internalised bacteria should be considered for further optimisation of ACP treatment parameters in order to achieve an effective control of the realistic challenges posed by foodborne pathogens. PMID:26093991

  18. Role of galE on biofilm formation by Thermus spp.

    PubMed

    Niou, Yi-Kai; Wu, Wan-Ling; Lin, Ling-Chun; Yu, Mei-Shiuan; Shu, Hung-Yu; Yang, Hsueh-Hui; Lin, Guang-Huey

    2009-12-11

    Thermus thermophilus and Thermus aquaticus are thermophilic bacteria that are frequently found to attach to solid surfaces in hot springs to form biofilms. Uridine diphosphate (UDP)-galactose-4'-epimerase (GalE) is an enzyme that catalyzes the conversion of UDP-galactose to UDP-glucose, an important biochemical step in exopolysaccharide synthesis. We expressed GalE obtained from T. thermophilus HB8 in Escherichia coli and found that the enzyme is stable at 80 degrees C and can epimerize UDP-galactose to UDP-glucose and UDP-N-acetylgalactosamine (UDP-GalNAc) to UDP-N-acetylglucosamine (UDP-GlcNAc). Enzyme overexpression in T. thermophilus HB27 led to an increased capacity of biofilm production. Therefore, the galE gene is important to biofilm formation because of its involvement in epimerizing UDP-galactose and UDP-N-acetylgalactosamine for exopolysaccharide biosynthesis. PMID:19800315

  19. Inhibition of biofilm formation by d-tyrosine: Effect of bacterial type and d-tyrosine concentration.

    PubMed

    Yu, Cong; Li, Xuening; Zhang, Nan; Wen, Donghui; Liu, Charles; Li, Qilin

    2016-04-01

    d-Tyrosine inhibits formation and triggers disassembly of bacterial biofilm and has been proposed for biofouling control applications. This study probes the impact of d-tyrosine in different biofilm formation stages in both G+ and G- bacteria, and reveals a non-monotonic correlation between d-tyrosine concentration and biofilm inhibition effect. In the attachment stage, cell adhesion was studied in a flow chamber, where d-tyrosine caused significant reduction in cell attachment. Biofilms formed by Pseudomonas aeruginosa and Bacillus subtilis were characterized by confocal laser scanning microscopy as well as quantitative analysis of cellular biomass and extracellular polymeric substances. d-Tyrosine exhibited strong inhibitive effects on both biofilms with an effective concentration as low as 5 nM; the biofilms responded to d-tyrosine concentration change in a non-monotonic, bi-modal pattern. In addition, d-tyrosine showed notable and different impact on EPS production by G+ and G- bacteria. Extracellular protein was decreased in P. aeruginosa biofilms, but increased in those of B. subtilis. Exopolysaccharides production by P. aeruginosa was increased at low concentrations and reduced at high concentrations while no impact was found in B. subtilis. These results suggest that distinct mechanisms are at play at different d-tyrosine concentrations and they may be species specific. Dosage of d-tyrosine must be carefully controlled for biofouling control applications. PMID:26854605

  20. DNase I and proteinase K impair Listeria monocytogenes biofilm formation and induce dispersal of pre-existing biofilms.

    PubMed

    Nguyen, Uyen T; Burrows, Lori L

    2014-09-18

    Current sanitation methods in the food industry are not always sufficient for prevention or dispersal of Listeria monocytogenes biofilms. Here, we determined if prevention of adherence or dispersal of existing biofilms could occur if biofilm matrix components were disrupted enzymatically. Addition of DNase during biofilm formation reduced attachment (<50% of control) to polystyrene. Treatment of established 72h biofilms with 100?g/ml of DNase for 24h induced incomplete biofilm dispersal, with <25% biofilm remaining compared to control. In contrast, addition of proteinase K completely inhibited biofilm formation, and 72h biofilms-including those grown under stimulatory conditions-were completely dispersed with 100?g/ml proteinase K. Generally-regarded-as-safe proteases bromelain and papain were less effective dispersants than proteinase K. In a time course assay, complete dispersal of L. monocytogenes biofilms from both polystyrene and type 304H food-grade stainless steel occurred within 5min at proteinase K concentrations above 25?g/ml. These data confirm that both DNA and proteins are required for L. monocytogenes biofilm development and maintenance, and that these components of the biofilm matrix can be targeted for effective prevention and removal of biofilms. PMID:25043896

  1. Apple Flavonoid Phloretin Inhibits Escherichia coli O157:H7 Biofilm Formation and Ameliorates Colon Inflammation in Rats ▿ †

    PubMed Central

    Lee, Jin-Hyung; Regmi, Sushil Chandra; Kim, Jung-Ae; Cho, Moo Hwan; Yun, Hyungdon; Lee, Chang-Soo; Lee, Jintae

    2011-01-01

    Pathogenic biofilms have been associated with persistent infections due to their high resistance to antimicrobial agents, while commensal biofilms often fortify the host's immune system. Hence, controlling biofilm formation of both pathogenic bacteria and commensal bacteria is important in bacterium-related diseases. We investigated the effect of plant flavonoids on biofilm formation of enterohemorrhagic Escherichia coli O157:H7. The antioxidant phloretin, which is abundant in apples, markedly reduced E. coli O157:H7 biofilm formation without affecting the growth of planktonic cells, while phloretin did not harm commensal E. coli K-12 biofilms. Also, phloretin reduced E. coli O157:H7 attachment to human colon epithelial cells. Global transcriptome analyses revealed that phloretin repressed toxin genes (hlyE and stx2), autoinducer-2 importer genes (lsrACDBF), curli genes (csgA and csgB), and dozens of prophage genes in E. coli O157:H7 biofilm cells. Electron microscopy confirmed that phloretin reduced fimbria production in E. coli O157:H7. Also, phloretin suppressed the tumor necrosis factor alpha-induced inflammatory response in vitro using human colonic epithelial cells. Moreover, in the rat model of colitis induced by trinitrobenzene sulfonic acid (TNBS), phloretin significantly ameliorated colon inflammation and body weight loss. Taken together, our results suggest that the antioxidant phloretin also acts as an inhibitor of E. coli O157:H7 biofilm formation as well as an anti-inflammatory agent in inflammatory bowel diseases without harming beneficial commensal E. coli biofilms. PMID:21930760

  2. Apple flavonoid phloretin inhibits Escherichia coli O157:H7 biofilm formation and ameliorates colon inflammation in rats.

    PubMed

    Lee, Jin-Hyung; Regmi, Sushil Chandra; Kim, Jung-Ae; Cho, Moo Hwan; Yun, Hyungdon; Lee, Chang-Soo; Lee, Jintae

    2011-12-01

    Pathogenic biofilms have been associated with persistent infections due to their high resistance to antimicrobial agents, while commensal biofilms often fortify the host's immune system. Hence, controlling biofilm formation of both pathogenic bacteria and commensal bacteria is important in bacterium-related diseases. We investigated the effect of plant flavonoids on biofilm formation of enterohemorrhagic Escherichia coli O157:H7. The antioxidant phloretin, which is abundant in apples, markedly reduced E. coli O157:H7 biofilm formation without affecting the growth of planktonic cells, while phloretin did not harm commensal E. coli K-12 biofilms. Also, phloretin reduced E. coli O157:H7 attachment to human colon epithelial cells. Global transcriptome analyses revealed that phloretin repressed toxin genes (hlyE and stx(2)), autoinducer-2 importer genes (lsrACDBF), curli genes (csgA and csgB), and dozens of prophage genes in E. coli O157:H7 biofilm cells. Electron microscopy confirmed that phloretin reduced fimbria production in E. coli O157:H7. Also, phloretin suppressed the tumor necrosis factor alpha-induced inflammatory response in vitro using human colonic epithelial cells. Moreover, in the rat model of colitis induced by trinitrobenzene sulfonic acid (TNBS), phloretin significantly ameliorated colon inflammation and body weight loss. Taken together, our results suggest that the antioxidant phloretin also acts as an inhibitor of E. coli O157:H7 biofilm formation as well as an anti-inflammatory agent in inflammatory bowel diseases without harming beneficial commensal E. coli biofilms. PMID:21930760

  3. Effect of UV-photofunctionalization on oral bacterial attachment and biofilm formation to titanium implant material.

    PubMed

    de Avila, Erica Dorigatti; Lima, Bruno P; Sekiya, Takeo; Torii, Yasuyoshi; Ogawa, Takahiro; Shi, Wenyuan; Lux, Renate

    2015-10-01

    Bacterial biofilm infections remain prevalent reasons for implant failure. Dental implant placement occurs in the oral environment, which harbors a plethora of biofilm-forming bacteria. Due to its trans-mucosal placement, part of the implant structure is exposed to oral cavity and there is no effective measure to prevent bacterial attachment to implant materials. Here, we demonstrated that UV treatment of titanium immediately prior to use (photofunctionalization) affects the ability of human polymicrobial oral biofilm communities to colonize in the presence of salivary and blood components. UV-treatment of machined titanium transformed the surface from hydrophobic to superhydrophilic. UV-treated surfaces exhibited a significant reduction in bacterial attachment as well as subsequent biofilm formation compared to untreated ones, even though overall bacterial viability was not affected. The function of reducing bacterial colonization was maintained on UV-treated titanium that had been stored in a liquid environment before use. Denaturing gradient gel-electrophoresis (DGGE) and DNA sequencing analyses revealed that while bacterial community profiles appeared different between UV-treated and untreated titanium in the initial attachment phase, this difference vanished as biofilm formation progressed. Our findings confirm that UV-photofunctionalization of titanium has a strong potential to improve outcome of implant placement by creating and maintaining antimicrobial surfaces. PMID:26210175

  4. Histo-FISH protocol to detect bacterial compositions and biofilms formation in vivo.

    PubMed

    Madar, M; Slizova, M; Czerwinski, J; Hrckova, G; Mudronova, D; Gancarcikova, S; Popper, M; Pistl, J; Soltys, J; Nemcova, R

    2015-12-01

    The study of biofilm function in vivo in various niches of the gastrointestinal tract (GIT) is rather limited. It is more frequently used in in vitro approaches, as an alternative to the studies focused on formation mechanisms and function of biofilms, which do not represent the actual in vivo complexity of microbial structures. Additionally, in vitro tests can sometimes lead to unreliable results. The goal of this study was to develop a simple approach to detect bacterial populations, particularly Lactobacillus and Bifidobacterium in biofilms, in vivo by the fluorescent in situ hybridisation (FISH) method. We standardised a new Histo-FISH method based on specific fluorochrome labelling probes which are able to detect Lactobacillus spp. and Bifidobacterium spp. within biofilms on the mucosal surface of the GIT embedded in paraffin in histological slices. This method is also suitable for visualisation of bacterial populations in the GIT internal content. Depending on the labelling probes, the Histo-FISH method has the potential to detect other probiotic strains or pathogenic bacteria. This original approach permits us to analyse bacterial colonisation processes as well as biofilm formation in stomach and caecum of BALB/c and germ-free mice. PMID:26123784

  5. Coexistence and survival of pathogenic leptospires by formation of biofilm with Azospirillum.

    PubMed

    Kumar, K Vinod; Lall, Chandan; Raj, R Vimal; Vedhagiri, K; Vijayachari, P

    2015-06-01

    Pathogenic Leptospira spp. represent one cause of leptospirosis worldwide and have long been regarded as solitary organisms in soil and aquatic environments. However, in the present study, Leptospira interrogans was observed to be associated with environmental biofilms with 21 bacterial isolates belonging to 10 genera. All 21 isolates were examined for their coaggregation and biofilm-forming ability with leptospires in vitro. Among these, Azospirillum brasilense RMRCPB showed maximum interspecies coaggregation with leptospiral strains (>75%, visual score of +4). Other significant coaggregating isolates belonged to the genera Sphingomonas, Micrococcus, Brevundimonas, Acinetobacter and Paracoccus. Biofilms of leptospires in combination with A. brasilense RMRCPB showed high resistance to penicillin G, ampicillin and tetracycline (minimum bactericidal concentration ≥800 μg/mL) and tolerance to UV radiation and high temperature (up to 49°C). This study hypothesized that biofilm formation with A. brasilense protects the pathogenic Leptospira from adverse environmental conditions/stress. This coexistence of pathogenic Leptospira with other bacteria may be the key factor for its persistence and survival. However, the mechanism of biofilm formation by leptospires needs to be explored to help devise an appropriate control strategy and reduce transmission of leptospires. PMID:25962762

  6. Cyclic-di-GMP signalling regulates motility and biofilm formation in Bordetella bronchiseptica

    PubMed Central

    Sisti, Federico; Ha, Dae-Gon; O'Toole, George A.; Hozbor, Daniela

    2013-01-01

    The signalling molecule bis-(3?5?)-cyclic-dimeric guanosine monophosphate (c-di-GMP) is a central regulator of diverse cellular functions, including motility, biofilm formation, cell cycle progression and virulence, in bacteria. Multiple diguanylate cyclase and phosphodiesterase-domain-containing proteins (GGDEF and EAL/HD-GYP, respectively) modulate the levels of the second messenger c-di-GMP to transmit signals and obtain such specific cellular responses. In the genus Bordetella this c-di-GMP network is poorly studied. In this work, we evaluated the expression of two phenotypes in Bordetella bronchiseptica regulated by c-di-GMP, biofilm formation and motility, under the influence of ectopic expression of Pseudomonas aeruginosa proteins with EAL or GGDEF domains that regulates the c-di-GMP level. In agreement with previous reports for other bacteria, we observed that B. bronchiseptica is able to form biofilm and reduce its motility only when GGDEF domain protein is expressed. Moreover we identify a GGDEF domain protein (BB3576) with diguanylate cyclase activity that participates in motility and biofilm regulation in B. bronchiseptica. These results demonstrate for the first time, to our knowledge, the presence of c-di-GMP regulatory signalling in B. bronchiseptica. PMID:23475948

  7. Biofilm Formation among Clinical and Food Isolates of Listeria monocytogenes

    PubMed Central

    Barbosa, Joana; Borges, Sandra; Camilo, Ruth; Magalhães, Rui; Ferreira, Vânia; Santos, Isabel; Silva, Joana; Almeida, Gonçalo; Teixeira, Paula

    2013-01-01

    Objective. A total of 725 Listeria monocytogenes isolates, 607 from various foods and 118 from clinical cases of listeriosis, were investigated concerning their ability to form biofilms, at 4°C during 5 days and at 37°C during 24 h. Methods. Biofilm production was carried out on polystyrene tissue culture plates. Five L. monocytogenes isolates were tested for biofilm formation after being exposed to acidic and osmotic stress conditions. Results. Significant differences (P < 0.01) between clinical and food isolates were observed. At 37°C for 24 h, most food isolates were classified as weak or moderate biofilm formers whereas all the clinical isolates were biofilm producers, although the majority were weak. At 4°C during 5 days, 65 and 59% isolates, from food and clinical cases, respectively, were classified as weak. After both sublethal stresses, at 37°C just one of the five isolates tested was shown to be more sensitive to subsequent acidic exposure. However, at 4°C both stresses did not confer either sensitivity or resistance. Conclusions. Significant differences between isolates origin, temperature, and sublethal acidic stress were observed concerning the ability to form biofilms. Strain, origin, and environmental conditions can determine the level of biofilm production by L. monocytogenes isolates. PMID:24489549

  8. Staphylokinase Control of Staphylococcus aureus Biofilm Formation and Detachment Through Host Plasminogen Activation.

    PubMed

    Kwiecinski, Jakub; Peetermans, Marijke; Liesenborghs, Laurens; Na, Manli; Bjrnsdottir, Halla; Zhu, Xuefeng; Jacobsson, Gunnar; Johansson, Bengt R; Geoghegan, Joan A; Foster, Timothy J; Josefsson, Elisabet; Bylund, Johan; Verhamme, Peter; Jin, Tao

    2016-01-01

    Staphylococcus aureus biofilms, a leading cause of persistent infections, are highly resistant to immune defenses and antimicrobial therapies. In the present study, we investigated the contribution of fibrin and staphylokinase (Sak) to biofilm formation. In both clinical S. aureus isolates and laboratory strains, high Sak-producing strains formed less biofilm than strains that lacked Sak, suggesting that Sak prevents biofilm formation. In addition, Sak induced detachment of mature biofilms. This effect depended on plasminogen activation by Sak. Host-derived fibrin, the main substrate cleaved by Sak-activated plasminogen, was a major component of biofilm matrix, and dissolution of this fibrin scaffold greatly increased susceptibility of biofilms to antibiotics and neutrophil phagocytosis. Sak also attenuated biofilm-associated catheter infections in mouse models. In conclusion, our results reveal a novel role for Sak-induced plasminogen activation that prevents S. aureus biofilm formation and induces detachment of existing biofilms through proteolytic cleavage of biofilm matrix components. PMID:26136471

  9. Biofilm streamer formation in a microfluidic porous media mimic

    NASA Astrophysics Data System (ADS)

    Kumar, Aloke; Valiei, Amin; Mukherjee, Partha; Liu, Yang; Thundat, Thomas

    2013-03-01

    Biofilm formation in porous media is of significant importance in many environmental and industrial processes such as bioremediation, oil recovery, and wastewater treatment. Among different biological and environmental factors, hydrodynamics is considered an important determinant of the dynamics of biofilm formation. In the present study, we fabricated a microfluidic porous media mimic and investigated how fluid flow influences the formation of filamentous structures, known as streamers, between porous media structures. Streamers are viscoelastic materials composed of extracellular polymeric substances (EPS) and bacterial cells, and these filamentous structures are typically tethered at either one of both ends to surfaces. We studied evolution of streamers in different flow rates and identified a tangible link between hydrodynamic conditions and development of these filamentous structures. Our results show that hydrodynamic conditions not only determine the limit of the streamers formation, but also influence both temporal evolution and spatial organization of biofilm streamers.

  10. Variation in sessile microflora during biofilm formation on AISI-304 stainless steel coupons.

    PubMed

    de França, F P; Lutterbach, M T

    1996-07-01

    Coupons of stainless steel type AISI-304 were exposed to the industrial cooling system of a petrochemical plant fed by seawater from the Guanabara Bay, Rio de Janeiro, Brazil, in order to study the in situ formation of biofilms. Bacteria, microalgae and fungi were detected on the coupons as soon as 48 h after exposure. Their respective numbers were determined at times 48, 96 and 192 h and over the following 8 weeks. Aerobic, anaerobic and sulfate-reducing bacteria were quantified according to the technique of the most probable number, and fungi by the pour plate technique. The number of microorganisms present in the forming biofilm varied over the experimental period, reaching maximal levels of 14 x 10(11) cells cm-2, 30 x 10(13) cells cm-2, 38 x 10(11) cells cm-2 and 63 x 10(5) cells cm-2, respectively, for aerobic bacteria, anaerobic bacteria, sulfate-reducing bacteria and fungi, and the dynamics of this variation depended on the group of microorganisms. Bacillus sp, Escherichia coli, Serratia sp and Pseudomonas putrefaciens were identified among the aerobic bacteria isolated. Additionally, microalgae and bacteria of the genus Gallionella were also detected. Nonetheless, no evidence of corrosion was found on the stainless steel type AISI-304 coupons over the experimental period. PMID:8987686

  11. Antifouling potential of bacteria isolated from a marine biofilm

    NASA Astrophysics Data System (ADS)

    Gao, Min; Wang, Ke; Su, Rongguo; Li, Xuzhao; Lu, Wei

    2014-10-01

    Marine microorganisms are a new source of natural antifouling compounds. In this study, two bacterial strains, Kytococcus sedentarius QDG-B506 and Bacillus cereus QDG-B509, were isolated from a marine biofilm and identified. The bacteria fermentation broth could exert inhibitory effects on the growth of Skeletonema costatum and barnacle larvae. A procedure was employed to extract and identify the antifouling compounds. Firstly, a toxicity test was conducted by graduated pH and liquid-liquid extraction to determine the optimal extraction conditions. The best extraction conditions were found to be pH 2 and 100% petroleum ether. The EC 50 value of the crude extract of K. sedentarius against the test microalgae was 236.7 14.08 ?g mL-1, and that of B. cereus was 290.6 27.11 ?g mL-1. Secondly, HLB SPE columns were used to purify the two crude extracts. After purification, the antifouling activities of the two extracts significantly increased: the EC 50 of the K. sedentarius extract against the test microalgae was 86.4 3.71 ?g mL-1, and that of B. cereus was 92.6 1.47 ?g mL-1. These results suggest that the metabolites produced by the two bacterial strains are with high antifouling activities and they should be fatty acid compounds. Lastly, GC-MS was used for the structural elucidation of the compounds. The results show that the antifouling compounds produced by the two bacterial strains are myristic, palmitic and octadecanoic acids.

  12. Irrigation waters and pipe-based biofilms as sources for antibiotic-resistant bacteria.

    PubMed

    Blaustein, Ryan A; Shelton, Daniel R; Van Kessel, Jo Ann S; Karns, Jeffrey S; Stocker, Matthew D; Pachepsky, Yakov A

    2016-01-01

    The presence of antibiotic-resistant bacteria in environmental surface waters has gained recent attention. Wastewater and drinking water distribution systems are known to disseminate antibiotic-resistant bacteria, with the biofilms that form on the inner-surfaces of the pipeline as a hot spot for proliferation and gene exchange. Pipe-based irrigation systems that utilize surface waters may contribute to the dissemination of antibiotic-resistant bacteria in a similar manner. We conducted irrigation events at a perennial stream on a weekly basis for 1 month, and the concentrations of total heterotrophic bacteria, total coliforms, and fecal coliforms, as well as the concentrations of these bacterial groups that were resistant to ampicillin and tetracycline, were monitored at the intake water. Prior to each of the latter three events, residual pipe water was sampled and 6-in. sections of pipeline (coupons) were detached from the system, and biofilm from the inner-wall was removed and analyzed for total protein content and the above bacteria. Isolates of biofilm-associated bacteria were screened for resistance to a panel of seven antibiotics, representing five antibiotic classes. All of the monitored bacteria grew substantially in the residual water between irrigation events, and the biomass of the biofilm steadily increased from week to week. The percentages of biofilm-associated isolates that were resistant to antibiotics on the panel sometimes increased between events. Multiple-drug resistance was observed for all bacterial groups, most often for fecal coliforms, and the distributions of the numbers of antibiotics that the total coliforms and fecal coliforms were resistant to were subject to change from week to week. Results from this study highlight irrigation waters as a potential source for antibiotic-resistant bacteria, which can subsequently become incorporated into and proliferate within irrigation pipe-based biofilms. PMID:26703979

  13. Role of the Clp System in Stress Tolerance, Biofilm Formation, and Intracellular Invasion in Porphyromonas gingivalis▿

    PubMed Central

    Capestany, Cindy A.; Tribble, Gena D.; Maeda, Kazuhiko; Demuth, Donald R.; Lamont, Richard J.

    2008-01-01

    Clp proteases and chaperones are ubiquitous among prokaryotes and eukaryotes, and in many pathogenic bacteria the Clp stress response system is also involved in regulation of virulence properties. In this study, the roles of ClpB, ClpC, and ClpXP in stress resistance, homotypic and heterotypic biofilm formation, and intracellular invasion in the oral opportunistic pathogen Porphyromonas gingivalis were investigated. Absence of ClpC and ClpXP, but not ClpB, resulted in diminished tolerance to high temperatures. Response to oxidative stress was not affected by the loss of any of the Clp proteins. The clpC and clpXP mutants demonstrated elevated monospecies biofilm formation, and the absence of ClpXP also enhanced heterotypic P. gingivalis-Streptococcus gordonii biofilm formation. All clp mutants adhered to gingival epithelial cells to the same level as the wild type; however, ClpC and ClpXP were found to be necessary for entry into host epithelial cells. ClpB did not play a role in entry but was required for intracellular replication and survival. ClpXP negatively regulated the surface exposure of the minor fimbrial (Mfa) protein subunit of P. gingivalis, which stimulates biofilm formation but interferes with epithelial cell entry. Collectively, these results show that the Clp protease complex and chaperones control several processes that are important for the colonization and survival of P. gingivalis in the oral cavity. PMID:18065546

  14. Virstatin inhibits biofilm formation and motility of Acinetobacter baumannii

    PubMed Central

    2014-01-01

    Background Acinetobacter baumannii has emerged as an opportunistic nosocomial pathogen causing infections worldwide. One reason for this emergence is due to its natural ability to survive in the hospital environment, which may be explained by its capacity to form biofilms. Cell surface appendages are important determinants of the A. baumannii biofilm formation and as such constitute interesting targets to prevent the development of biofilm-related infections. A chemical agent called virstatin was recently described to impair the virulence of Vibrio cholerae by preventing the expression of its virulence factor, the toxin coregulated pilus (type IV pilus). The objective of this work was to investigate the potential effect of virstatin on A. baumannii biofilms. Results After a doseresponse experiment, we determined that 100?M virstatin led to an important decrease (38%) of biofilms formed by A. baumannii ATCC17978 grown under static mode. We demonstrated that the production of biofilms grown under dynamic mode was also delayed and reduced. The biofilm susceptibility to virstatin was then tested for 40 clinical and reference A. baumannii strains. 70% of the strains were susceptible to virstatin (with a decrease of 10 to 65%) when biofilms grew in static mode, whereas 60% of strains respond to the treatment when their biofilms grew in dynamic mode. As expected, motility and atomic force microscopy experiments showed that virstatin acts on the A. baumannii pili biogenesis. Conclusions By its action on pili biogenesis, virstatin demonstrated a very promising antibiofilm activity affecting more than 70% of the A. baumannii clinical isolates. PMID:24621315

  15. Diacetyl formation by lactic bacteria.

    TOXLINE Toxicology Bibliographic Information

    Escamilla-Hurtado ML; Tomasini-Campocosio A; Valds-Martnez S; Soriano-Santos J

    1996-04-01

    Some of the most widely used products in the food industry are flavour compounds. These products can be obtained either by chemical synthesis and therefore are called synthetic or by fermentation thus called natural flavors. There is a tendency towards the use of natural products by the consumer, therefore there is an increasing industrial interest in them. One of these products is diacetyl, an important component in the flavor of butter, although others, like acetoin, acetaldehyde and 2,3-butanediol play a role in the flavor, they are present in trace amounts. The mixture of all these compounds produced during the lactic acid fermentation in suitable proportions is what gives butter its characteristic flavor. The most common metabolic route that produces diacetyl is the one starting from pyruvate, in this case it seems that the biosynthesis is related to the presence of citrate in the medium. An alternative route for the production is from acetaldehyde, in this route citrate does not seem to intervene. In the present paper a review of the mechanisms of formation of diacetyl by lactic acid bacteria, as well as the most important factors that influence the biosynthesis of this metabolite is made.

  16. Diacetyl formation by lactic bacteria.

    PubMed

    Escamilla-Hurtado, M L; Tomasini-Campocosio, A; Valds-Martnez, S; Soriano-Santos, J

    1996-01-01

    Some of the most widely used products in the food industry are flavour compounds. These products can be obtained either by chemical synthesis and therefore are called synthetic or by fermentation thus called natural flavors. There is a tendency towards the use of natural products by the consumer, therefore there is an increasing industrial interest in them. One of these products is diacetyl, an important component in the flavor of butter, although others, like acetoin, acetaldehyde and 2,3-butanediol play a role in the flavor, they are present in trace amounts. The mixture of all these compounds produced during the lactic acid fermentation in suitable proportions is what gives butter its characteristic flavor. The most common metabolic route that produces diacetyl is the one starting from pyruvate, in this case it seems that the biosynthesis is related to the presence of citrate in the medium. An alternative route for the production is from acetaldehyde, in this route citrate does not seem to intervene. In the present paper a review of the mechanisms of formation of diacetyl by lactic acid bacteria, as well as the most important factors that influence the biosynthesis of this metabolite is made. PMID:8986113

  17. Functional analysis of the protein Veg, which stimulates biofilm formation in Bacillus subtilis.

    PubMed

    Lei, Ying; Oshima, Taku; Ogasawara, Naotake; Ishikawa, Shu

    2013-04-01

    Biofilm is a complex aggregate of cells that adhere to each other and produce an extracellular matrix. In Bacillus subtilis, an extracellular polysaccharide (EPS) and amyloid fiber (TasA), synthesized by the epsA-epsO and tapA-sipW-tasA operons, respectively, are the primary components of the extracellular matrix. In the current study, we investigated the functional role of the previously uncharacterized veg gene in B. subtilis. Overproduction of Veg, a small protein highly conserved among Gram-positive bacteria, stimulated biofilm formation via inducing transcription of the tapA-sipW-tasA operon. Moreover, overproduced Veg restored the impairment of biofilm formation in mutants carrying a deletion of of sinI, slrA, or slrR, encoding an antirepressor of SinR that acts as the master regulator of biofilm formation, while biofilm morphology in the absence of SinR was not affected by either additional veg deletion or overproduction, indicating that Veg negatively regulates SinR activity independently of the known antirepressors. Expression of sinR was not affected in Veg-overproducing cells, and amounts of SinR were similar in cells expressing different levels of Veg, strongly suggesting that Veg modulates the repressor activity of SinR. Interestingly, the results of in vivo pulldown assays of the SinR complex indicate that Veg inhibits the interactions between SinR and SlrR. Based on these findings, we propose that Veg or a Veg-induced protein acts as an antirepressor of SinR to regulate biofilm formation. PMID:23378512

  18. Combined effects of NaF and SLS on acid- and polysaccharide-formation of biofilm and planktonic cells.

    PubMed

    Petersen, Fernanda C; Assev, Synnve; Scheie, Anne Aa

    2006-08-01

    Bacteria grow preferentially attached to surfaces embedded in an exopolysaccharide matrix to form biofilms. In this mode of growth, bacteria often show reduced susceptibility to antimicrobials. The aim of this study was to investigate whether the combination of NaF and the detergent sodium lauryl sulphate (SLS) could result in additive effects on acid formation by planktonic and biofilm cells, as well as on extracellular polysaccharide formation. An additive inhibitory effect on Streptococcus mutans acid formation was observed, both in planktonic and biofilm cells. In dental biofilms, SLS alone and in combination with NaF reduced acid formation. Extracellular polysaccharide formation by S. mutans and saliva was reduced by SLS alone and in combination with NaF. In dentifrices and mouthrinse solutions, NaF and SLS are often present in combination. It remains to be determined whether an additive effect on acid formation may also occur in dental biofilms under different concentrations from those used in the present study, and whether the effects may be selective for certain bacterial species. PMID:16540078

  19. Enzymatic catalysis of mercury methylation by planktonic and biofilm cultures of sulfate- reducing bacteria

    NASA Astrophysics Data System (ADS)

    Lin, C.; Kampalath, R.; Jay, J.

    2007-12-01

    While biofilms are now known to be the predominant form of microbial growth in nature, little is known about their role in environmental mercury (Hg) methylation. Due to its long-range atmospheric transport, Hg contamination of food chains is a worldwide problem, impacting even pristine areas. Among different forms of mercury species, methylmercury (MeHg) is an extremely neurotoxic and biomagnification-prone compound that can lead to severely adverse health effects on wildlife and humans. Considerable studies have shown that in the aquatic environment the external supply of MeHg is not sufficient to account for MeHg accumulation in biota and in situ biological MeHg formation plays a critical role in determining the amount of MeHg in food webs; moreover, sulfate-reducing bacteria (SRB) has been identified as the principal Hg-methylating organisms in nature. In a wide range of aquatic systems wetlands are considered important sites for Hg methylation mostly because of the environmental factors that promote microbial activity within, and biofilms are especially important in wetland ecosystems due to large amount of submerged surfaces. Although recent work has focused on the environmental factors that control MeHg production and the conditions that affect the availability of inorganic Hg to SRB, much remains to be understood about the biochemical mechanism of the Hg methylation process in SRB, especially in the biofilm-growth of these microbes. Data from our previous study with SRB strains isolated from a coastal wetland suggested that the specific Hg methylation rate found was approximately an order of magnitude higher in biofilm cells than in planktonic cells. In order to investigate possible reasons for this observed difference, and to test if this phenomenon is observed in other strains, we conducted chloroform, fluroacetate and molybdate inhibition assays in both complete and incomplete-oxidizing SRB species (Desulfovibrio desulfuricans M8, Desulfococcus sp. Desulfobactor sp. BG8) grown in planktonic and biofilm form, as the acetyl- coenzyme A pathway involved with cobalamin has been hypothesized to be the pathway for Hg methylation. The purpose of this study was to probe whether differences in the enzymatically catalyzed process caused differential methylation rates between the species and also between the different forms of culture growth. Any attempts to control the environmentally undesirable Hg methylation process would benefit from a better understanding of the biochemical mechanism involved.

  20. Bacterial quorum sensing and biofilm formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quorum sensing is a cell density-dependent signaling system by which bacteria can regulate gene expression through the production, secretion, and subsequent detection of extracellular signaling molecules called autoinducers. Bacteria use quorum sensing to regulate various physiological activities, ...

  1. Cattle tick-associated bacteria exert anti-biofilm and anti-Tritrichomonas foetus activities.

    PubMed

    Zimmer, K R; Seixas, A; Conceio, J M; Zvoboda, D A; Barros, M P; Tasca, T; Macedo, A J; Termignoni, C

    2013-05-31

    Research on microbiota in cattle tick and the evaluation of its activity against other microorganisms can contribute to identify new molecules potentially useful to control infections caused by bacteria and protozoa. Biofilms pose increasing problems worldwide, mainly due to their resistance to antimicrobial therapies and host immune response. In this study we investigate the ability Rhipicephalus (Boophilus) microplus-associated bacteria may exhibit to produce anti-biofilm and trichomonicidal compounds. Gut, ovary, salivary glands, and Gen organ were collected from engorged R. microplus female. Homogenates of each tissue were inoculated onto 15 distinct culture media. Anti-biofilm and trichomonicidal activities were analyzed by culturing each bacterium isolated in a liquid medium. Results showed that R. microplus cattle tick microflora varies for different tissues. Bacteria belonging to different genera (Aeromonas, Bacillus, Brevibacillus, Castelaniella, Comamonas, Kocuria, and Microbacterium) were identified. Interestingly, all bacterial species found displayed pronounced activity against Staphylococcus epidermidis and Pseudomonas aeruginosa biofilms, and also against the cattle pathogen Tritrichomonas foetus, confirming the hypothesis that cattle tick could be a source of bacteria active against pathogens. This is the first study showing that bacteria isolated from a tick exert anti-biofilm and trichomonicidal activities. PMID:23434012

  2. Molecular and cellular mechanisms that lead to Candida biofilm formation.

    PubMed

    ten Cate, J M; Klis, F M; Pereira-Cenci, T; Crielaard, W; de Groot, P W J

    2009-02-01

    Fungal infections in the oral cavity are mainly caused by C. albicans, but other Candida species are also frequently identified. They are increasing in prevalence, especially in denture-wearers and aging people, and may lead to invasive infections, which have a high mortality rate. Attachment to mucosal tissues and to abiotic surfaces and the formation of biofilms are crucial steps for Candida survival and proliferation in the oral cavity. Candida species possess a wide arsenal of glycoproteins located at the exterior side of the cell wall, many of which play a determining role in these steps. In addition, C. albicans secretes signaling molecules that inhibit the yeast-to-hypha transition and biofilm formation. In vivo, Candida species are members of mixed biofilms, and subject to various antagonistic and synergistic interactions, which are beginning to be explored. We believe that these new insights will allow for more efficacious treatments of fungal oral infections. For example, the use of signaling molecules that inhibit biofilm formation should be considered. In addition, cell-wall biosynthetic enzymes, wall cross-linking enzymes, and wall proteins, which include adhesins, proteins involved in biofilm formation, fungal-bacterial interactions, and competition for surface colonization sites, offer a wide range of potential targets for therapeutic intervention. PMID:19278980

  3. Current concepts in biofilm formation of Staphylococcus epidermidis

    PubMed Central

    Fey, Paul D; Olson, Michael E

    2010-01-01

    Staphylococcus epidermidis is a highly significant nosocomial pathogen mediating infections primarily associated with indwelling biomaterials (e.g., catheters and prostheses). In contrast to Staphylococcus aureus, virulence properties associated with S. epidermidis are few and biofilm formation is the defining virulence factor associated with disease, as demonstrated by animal models of biomaterial-related infections. However, other virulence factors, such as phenol-soluble modulins and poly-γ-DL-glutamic acid, have been recently recognized that thwart innate immune system mechanisms. Formation of S. epidermidis biofilm is typically considered a four-step process consisting of adherence, accumulation, maturation and dispersal. This article will discuss recent advances in the study of these four steps, including accumulation, which can be either polysaccharide or protein mediated. It is hypothesized that studies focused on understanding the biological function of each step in staphylococcal biofilm formation will yield new treatment modalities to treat these recalcitrant infections. PMID:20521936

  4. [PNEUMOCOCCAL BIOFILMS AS A FORM OF PERSISTENCE: FORMATION, STRUCTURE, ROLE IN PATHOGENESIS, IMMUNE RESPONSE].

    PubMed

    Kostyukova, N N; Bekhalo, V A

    2015-01-01

    A review of studies on pneumococcal biofilms as a form of persistence is presented. The following provisions are examined: formation of pneumococcal biofilm on abiotic and mucosal surfaces, pathogenetic significance of biofilm pneumococci, their immunogenicity, as well as resistance to antibiotics and unfavorable environmental factors. Differences between biofilm properties, that are formed in vivo and in vitro, are shown. The significance of pneumococcal biofilm formation as means of survival for a long time is underscored. PMID:26470420

  5. A Novel Cell Wall Lipopeptide Is Important for Biofilm Formation and Pathogenicity of Mycobacterium avium subspecies paratuberculosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofilm formation by pathogenic bacteria plays a key role in their pathogenesis. Previously, the pstA gene was shown to be involved in the virulence of Mycobacterium avium subspecies paratuberculosis (M. ap), the causative agent of Johne's disease in cattle and a potential risk factor for Crohn's d...

  6. Influence of curli expression on biofilm formation and attachment to plant surface by shiga toxigenic E. coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga-toxigenic Escherichia coli O157:H7 (STEC) outbreaks have been linked to consumption of fresh produce. Bacteria extracellular appendages, such as curli fibers and cellulose may play critical role in STEC biofilm formation and adherence to plant surface. We determined cellulose and curli product...

  7. The impact of influent total ammonium nitrogen concentration on nitrite-oxidizing bacteria inhibition in moving bed biofilm reactor.

    PubMed

    Kouba, Vojtech; Catrysse, Michael; Stryjova, Hana; Jonatova, Ivana; Volcke, Eveline I P; Svehla, Pavel; Bartacek, Jan

    2014-01-01

    The application of nitrification-denitrification over nitrite (nitritation-denitritation) with municipal (i.e. diluted and cold (or low-temperature)) wastewater can substantially improve the energy balance of municipal wastewater treatment plants. For the accumulation of nitrite, it is crucial to inhibit nitrite-oxidizing bacteria (NOB) with simultaneous proliferation of ammonium-oxidizing bacteria (AOB). The present study describes the effect of the influent total ammonium nitrogen (TAN) concentration on AOB and NOB activity in two moving bed biofilm reactors operated as sequencing batch reactors (SBR) at 15 C (SBR I) and 21 C (SBR II). The reactors were fed with diluted reject water containing 600, 300, 150 and 75 mg TAN L(-1). The only factor limiting NOB activity in these reactors was the high concentrations of free ammonia and/or free nitrous acid (FNA) during the SBR cycles. Nitrite accumulation was observed with influents containing 600, 300 and 150 mg TAN L(-1) in SBR I and 600 and 300 in SBR II. Once nitrate production established in the reactors, the increase of influent TAN concentration up to the original 600 mg TAN L(-1) did not limit NOB activity. This was due to the massive development of NOB clusters throughout the biofilm that were able to cope with faster formation of FNA. The results of the fluorescence in situ hybridization analysis preliminarily showed the stratification of bacteria in the biofilm. PMID:24647188

  8. Bacillus subtilis Bacteria Generate an Internal Mechanical Force within a Biofilm.

    PubMed

    Douarche, Carine; Allain, Jean-Marc; Raspaud, Eric

    2015-11-17

    A key issue in understanding why biofilms are the most prevalent mode of bacterial life is the origin of the degree of resistance and protection that bacteria gain from self-organizing into biofilm communities. Our experiments suggest that their mechanical properties are a key factor. Experiments on pellicles, or floating biofilms, of Bacillus subtilis showed that while they are multiplying and secreting extracellular substances, bacteria create an internal force (associated with a -80±25 Pa stress) within the biofilms, similar to the forces that self-equilibrate and strengthen plants, organs, and some engineered buildings. Here, we found that this force, or stress, is associated with growth-induced pressure. Our observations indicate that due to such forces, biofilms spread after any cut or ablation by up to 15-20% of their initial size. The force relaxes over very short timescales (tens of milliseconds). We conclude that this force helps bacteria to shape the biofilm, improve its mechanical resistance, and facilitate its invasion and self-repair. PMID:26588577

  9. Selected dietary (poly)phenols inhibit periodontal pathogen growth and biofilm formation.

    PubMed

    Shahzad, Muhammad; Millhouse, Emma; Culshaw, Shauna; Edwards, Christine A; Ramage, Gordon; Combet, Emilie

    2015-03-01

    Periodontitis (PD) is a chronic infectious disease mediated by bacteria in the oral cavity. (Poly)phenols (PPs), ubiquitous in plant foods, possess antimicrobial activities and may be useful in the prevention and management of periodontitis. The objective of this study was to test the antibacterial effects of selected PPs on periodontal pathogens, on both planktonic and biofilm modes of growth. Selected PPs (n = 48) were screened against Streptococcus mitis (S. mitis), Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis). The antibacterial potential of each compound was evaluated in terms of planktonic minimum inhibitory concentration (PMIC) and planktonic minimum bactericidal concentration (PMBC) using standardized broth microdilution assays. The most active PPs were further tested for their effect on mono-species and multi-species biofilms using a colorimetric resazurin-based viability assay and scanning electron microscopy. Of the 48 PPs tested, 43 showed effective inhibition of planktonic growth of one or more test strains, of which curcumin was the most potent (PMIC range = 7.8-62.5 ?g mL(-1)), followed by pyrogallol (PMIC range = 2.4-2500 ?g mL(-1)), pyrocatechol (MIC range = 4.9-312.5 ?g mL(-1)) and quercetin (PMIC range = 31.2-500 ?g mL(-1)). At this concentration, adhesion of curcumin and quercetin to the substrate also inhibited adhesion of S. mitis, and biofilm formation and maturation. While both curcumin and quercetin were able to alter architecture of mature multi-species biofilms, only curcumin-treated biofilms displayed a significantly reduced metabolic activity. Overall, PPs possess antibacterial activities against periodontopathic bacteria in both planktonic and biofilm modes of growth. Further cellular and in vivo studies are necessary to confirm their beneficial activities and potential use in the prevention and or treatment of periodontal diseases. PMID:25585200

  10. Purpurin Suppresses Candida albicans Biofilm Formation and Hyphal Development

    PubMed Central

    Tsang, Paul Wai-Kei; Bandara, H. M. H. N.; Fong, Wing-Ping

    2012-01-01

    A striking and clinically relevant virulence trait of the human fungal pathogen Candida albicans is its ability to grow and switch reversibly among different morphological forms. Inhibition of yeast-to-hypha transition in C. albicans represents a new paradigm for antifungal intervention. We have previously demonstrated the novel antifungal activity of purpurin against Candida fungi. In this study, we extended our investigation by examining the in vitro effect of purpurin on C. albicans morphogenesis and biofilms. The susceptibility of C. albicans biofilms to purpurin was examined quantitatively by 2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide reduction assay. Hyphal formation and biofilm ultrastructure were examined qualitatively by scanning electron microscopy (SEM). Quantitative reverse transcription-PCR (qRT-PCR) was used to evaluate the expression of hypha-specific genes and hyphal regulator in purpurin-treated fungal cells. The results showed that, at sub-lethal concentration (3 µg/ml), purpurin blocked the yeast-to-hypha transition under hypha-inducing conditions. Purpurin also inhibited C. albicans biofilm formation and reduced the metabolic activity of mature biofilms in a concentration-dependent manner. SEM images showed that purpurin-treated C. albicans biofilms were scanty and exclusively consisted of aggregates of blastospores. qRT-PCR analyses indicated that purpurin downregulated the expression of hypha-specific genes (ALS3, ECE1, HWP1, HYR1) and the hyphal regulator RAS1. The data strongly suggested that purpurin suppressed C. albicans morphogenesis and caused distorted biofilm formation. By virtue of the ability to block these two virulence traits in C. albicans, purpurin may represent a potential candidate that deserves further investigations in the development of antifungal strategies against this notorious human fungal pathogen in vivo. PMID:23226409

  11. Role of Candida albicans secreted aspartyl protease Sap9 in interkingdom biofilm formation.

    PubMed

    Dutton, Lindsay C; Jenkinson, Howard F; Lamont, Richard J; Nobbs, Angela H

    2016-04-01

    The fungus Candida albicans colonizes oral cavity surfaces and is carried by up to 60% of human populations. Biofilm development by C. albicans may be modulated by oral streptococci, such as Streptococcus gordonii, S. oralis or S. mutans, so as to augment pathogenicity. In this study we sought to determine if the cell wall-associated secreted aspartyl proteinase Sap9 was necessary for hyphal adhesin functions associated with biofilm community development. A sap9Δ mutant of C. albicans SC5314 formed biofilms that were flatter, and contained fewer blastospores and more hyphal filaments than the parent strain. This phenotypic difference was accentuated under flow (shear) conditions and in the presence of S. gordonii. Dual-species biofilms of C. albicans sap9Δ with S. oralis, S. sanguinis, S. parasanguinis, S. mutans and Enterococcus faecalis all contained more matted hyphae and more bacteria bound to substratum compared to C. albicans wild type. sap9Δ mutant hyphae showed significantly increased cell surface hydrophobicity, ∼25% increased levels of binding C. albicans cell wall protein Als3, and reduced interaction with Eap1, implicating Sap9 in fungal cell-cell recognition. These observations suggest that Sap9 is associated with protein-receptor interactions between fungal cells, and with interkingdom communication in the formation of polymicrobial biofilm communities. PMID:26772652

  12. Attenuation of Pseudomonas aeruginosa biofilm formation by Vitexin: A combinatorial study with azithromycin and gentamicin.

    PubMed

    Das, Manash C; Sandhu, Padmani; Gupta, Priya; Rudrapaul, Prasenjit; De, Utpal C; Tribedi, Prosun; Akhter, Yusuf; Bhattacharjee, Surajit

    2016-01-01

    Microbial biofilm are communities of surface-adhered cells enclosed in a matrix of extracellular polymeric substances. Extensive use of antibiotics to treat biofilm associated infections has led to the emergence of multiple drug resistant strains. Pseudomonas aeruginosa is recognised as a model biofilm forming pathogenic bacterium. Vitexin, a polyphenolic group of phytochemical with antimicrobial property, has been studied for its antibiofilm potential against Pseudomonas aeruginosa in combination with azithromycin and gentamicin. Vitexin shows minimum inhibitory concentration (MIC) at 260 μg/ml. It's antibiofilm activity was evaluated by safranin staining, protein extraction, microscopy methods, quantification of EPS and in vivo models using several sub-MIC doses. Various quorum sensing (QS) mediated phenomenon such as swarming motility, azocasein degrading protease activity, pyoverdin and pyocyanin production, LasA and LasB activity of the bacteria were also evaluated. Results showed marked attenuation in biofilm formation and QS mediated phenotype of Pseudomonas aeruginosa in presence of 110 μg/ml vitexin in combination with azithromycin and gentamicin separately. Molecular docking of vitexin with QS associated LuxR, LasA, LasI and motility related proteins showed high and reasonable binding affinity respectively. The study explores the antibiofilm potential of vitexin against P. aeruginosa which can be used as a new antibiofilm agent against microbial biofilm associated pathogenesis. PMID:27000525

  13. Attenuation of Pseudomonas aeruginosa biofilm formation by Vitexin: A combinatorial study with azithromycin and gentamicin

    PubMed Central

    Das, Manash C.; Sandhu, Padmani; Gupta, Priya; Rudrapaul, Prasenjit; De, Utpal C.; Tribedi, Prosun; Akhter, Yusuf; Bhattacharjee, Surajit

    2016-01-01

    Microbial biofilm are communities of surface-adhered cells enclosed in a matrix of extracellular polymeric substances. Extensive use of antibiotics to treat biofilm associated infections has led to the emergence of multiple drug resistant strains. Pseudomonas aeruginosa is recognised as a model biofilm forming pathogenic bacterium. Vitexin, a polyphenolic group of phytochemical with antimicrobial property, has been studied for its antibiofilm potential against Pseudomonas aeruginosa in combination with azithromycin and gentamicin. Vitexin shows minimum inhibitory concentration (MIC) at 260 μg/ml. It’s antibiofilm activity was evaluated by safranin staining, protein extraction, microscopy methods, quantification of EPS and in vivo models using several sub-MIC doses. Various quorum sensing (QS) mediated phenomenon such as swarming motility, azocasein degrading protease activity, pyoverdin and pyocyanin production, LasA and LasB activity of the bacteria were also evaluated. Results showed marked attenuation in biofilm formation and QS mediated phenotype of Pseudomonas aeruginosa in presence of 110 μg/ml vitexin in combination with azithromycin and gentamicin separately. Molecular docking of vitexin with QS associated LuxR, LasA, LasI and motility related proteins showed high and reasonable binding affinity respectively. The study explores the antibiofilm potential of vitexin against P. aeruginosa which can be used as a new antibiofilm agent against microbial biofilm associated pathogenesis. PMID:27000525

  14. Study of Biofilm in Bacteria from Water Pipelines

    PubMed Central

    Padhi, Nupur; Mahapatra, Dharitri; Bhatt, Mamta; Sahoo, Debasish; Jena, Swetlina; Dash, Debabrata; Chayani, Nirupama

    2015-01-01

    Context: A biofilm is a layer of microorganisms contained in a matrix (slime layer), which forms on surfaces in contact with water. Their presence in drinking water pipe networks can be responsible for a wide range of water quality and operational problems. Aim: To identify the bacterial isolates, obtained from water pipelines of kitchens, to evaluate the water quality & to study the biofilm producing capacity of the bacterial isolates from various sources. Settings and Design: A prospective study using water samples from aqua guard & pipelines to kitchens of S.C.B Medical College hostels. Materials and Methods: Standard biochemical procedures for bacterial identification, multiple tube culture & MPN count to evaluate water quality & tissue culture plate (TCP) method for biofilm detection was followed. Statistical analysis: STATA software version 9.2 from STATA Corporation, College station road, 90 Houston, Texas was used for statistical analysis. Results: One hundred eighty seven isolates were obtained from 45 water samples cultured. The isolates were Acinetobacter spp. (44), Pseudomonas spp.(41), Klebsiella spp.(36) & others . Biofilm was detected in (37) 19.78 % of the isolates (95% CI 30.08% -43.92%) including Acinetobacter spp.-10, Klebsiella spp. - 9, Pseudomonas spp. - 9, & others, majority (34) of which were from kitchen pipelines. Conclusion: Water from pipeline sources was unsatisfactory for consumption as the MPN counts were > 10. Most of the biofilm producers were gram negative bacilli & Pseudomonas & Acinetobacter spp. were strong (4+) biofilm producers. PMID:25954617

  15. Propionibacterium-Produced Coproporphyrin III Induces Staphylococcus aureus Aggregation and Biofilm Formation

    PubMed Central

    Wollenberg, Michael S.; Claesen, Jan; Escapa, Isabel F.; Aldridge, Kelly L.; Fischbach, Michael A.

    2014-01-01

    ABSTRACT The majority of bacteria detected in the nostril microbiota of most healthy adults belong to three genera: Propionibacterium, Corynebacterium, and Staphylococcus. Among these staphylococci is the medically important bacterium Staphylococcus aureus. Almost nothing is known about interspecies interactions among bacteria in the nostrils. We observed that crude extracts of cell-free conditioned medium from Propionibacterium spp. induce S. aureus aggregation in culture. Bioassay-guided fractionation implicated coproporphyrin III (CIII), the most abundant extracellular porphyrin produced by human-associated Propionibacterium spp., as a cause of S. aureus aggregation. This aggregation response depended on the CIII dose and occurred during early stationary-phase growth, and a low pH (~4 to 6) was necessary but was not sufficient for its induction. Additionally, CIII induced plasma-independent S. aureus biofilm development on an abiotic surface in multiple S. aureus strains. In strain UAMS-1, CIII stimulation of biofilm depended on sarA, a key biofilm regulator. This study is one of the first demonstrations of a small-molecule-mediated interaction among medically relevant members of the nostril microbiota and the first description of a role for CIII in bacterial interspecies interactions. Our results indicate that CIII may be an important mediator of S. aureus aggregation and/or biofilm formation in the nostril or other sites inhabited by Propionibacterium spp. and S. aureus. PMID:25053784

  16. Inhibition of biofilm formation and antibacterial properties of a silver nano-coating on human dentine.

    PubMed

    Besinis, Alexandros; De Peralta, Tracy; Handy, Richard D

    2014-11-01

    The survival of pathogenic bacteria in the oral cavity depends on their successful adhesion to dental surfaces and their ability to develop into biofilms, known as dental plaque. Bacteria from the dental plaque are responsible for the development of dental caries, gingivitis, periodontitis, stomatitis and peri-implantitis. Certain metal nanoparticles have been suggested for infection control and the management of the oral biofilm. Here, it is shown that application of a silver nano-coating directly on dentine can successfully prevent the biofilm formation on dentine surfaces as well as inhibit bacterial growth in the surrounding media. This silver nano-coating was found to be stable (>98.8%) and to maintain its integrity in biological fluids. Its antibacterial activity was compared to silver nitrate and the widely used clinical antiseptic, chlorhexidine. The bacterial growth and cell viability were quantitatively assessed by measuring the turbidity, proportion of live and dead cells and lactate production. All three bioassays showed that silver nanoparticles and silver nitrate dentine coatings were equally highly bactericidal (>99.5%), while inhibiting bacterial adhesion. However, the latter caused significant dentine discolouration (ΔE* = 50.3). The chlorhexidine coating showed no antibacterial effect. Thus, silver nanoparticles may be a viable alternative to both chlorhexidine and silver nitrate, protecting from dental plaque and secondary caries when applied as a dentine coating, while they may provide the platform for creating anti-biofilm surfaces in medical devices and other biomedical applications. PMID:23875717

  17. Conditioning film and initial biofilm formation on ceramics tiles in the marine environment.

    PubMed

    Siboni, Nachshon; Lidor, Michal; Kramarsky-Winter, Esti; Kushmaro, Ariel

    2007-09-01

    The formation of biofilm on surfaces in the marine environment is believed to be an important factor driving colonization and recruitment of some sessile invertebrate communities. The present study follows the process of biofilm buildup on unglazed ceramic tiles deployed into the marine environment in the northern Gulf of Eilat. PCR-DGGE of film eluted from the tile surface indicated the presence of bacteria as early as 2 h after deployment. The makeup of the biofilm bacterial community was dynamic. Bacterial presence was apparent microscopically 6 h after deployment, though a developed biofilm was not observed until 24 h following deployment. Total organic carbon (TOC) data suggest that a conditioning film was built within the first four hours following deployment. During this time period TOC reached the highest level possibly due to adhesion of organics (e.g., sugars, proteins and humic substances) from the water column. We suggest that the primary adhering bacteria, whilst still in the reversible stage of adhesion, utilize the conditioning film as food causing the decrease in TOC. Understanding the dynamics between these primary bacterial settlers is of importance, since they may play a role on the succession of invertebrate species settlement onto artificial surfaces. PMID:17578524

  18. Biofilm formation by oral clinical isolates of Candida species.

    PubMed

    Sánchez-Vargas, Luis Octavio; Estrada-Barraza, Deyanira; Pozos-Guillen, Amaury J; Rivas-Caceres, Raimundo

    2013-10-01

    We have conducted a longitudinal study to quantify biofilms in oral clinical isolates of Candida species (spp.) from adults with local and systemic predisposing factors for candidiasis. A total of 69 yeast isolates from 63 Mexican patients were evaluated. These isolates (39 C. albicans, 15 C. tropicalis, 7 C. glabrata, 4 C. krusei, 1 C. lusitaniae, 1 C. kefyr, 1 C. guilliermondii and 1 C. pulcherrima) were obtained from two clinical sites: 62.3% (n=43) from the oral mucosa of totally and partially edentulous patients, and 37.7% (n=26) from the oral mucosa of diabetics. In addition, Candida ATCC strains were used as controls for each experiment. The kinetics of biofilm formation were measured by 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide [XTT] reduction; each isolate was tested at 6, 12 and 24h. Biofilm formation is dependent on the Candida spp. and its clinical origin. On average, the oral isolates of C. glabrata are strong biofilm producers, whereas C. albicans and C. tropicalis are moderate producers. The most common species in our population was C. albicans. While the kinetics of C. albicans biofilm formation varies between oral isolates, it generally maintains steady growth from 2 to 48h, when it reaches its maximum growth. PMID:23849353

  19. Aggregatibacter actinomycetemcomitans arcB influences hydrophobic properties, biofilm formation and adhesion to hydroxyapatite

    PubMed Central

    Longo, PL; Ota-Tsuzuki, C; Nunes, ACR; Fernandes, BL; Mintz, K; Fives-Taylor, P; Mayer, MPA

    2009-01-01

    The regulation of gene expression in the oral pathogen Aggregatibacter actinomycetemcomitans is still not fully elucidated. ArcAB is a two-component system which allows facultative anaerobic bacteria to sense various respiratory growth conditions and adapt their gene expression accordingly.This study investigated in A. actinomycetemcomitans the role of ArcB on the regulation of biofilm formation, adhesion to saliva coated hydroxyapatite (SHA) and the hydrophobic properties of the cell. These phenotypic traits were determined for an A. actinomycetemcomitans arcB deficient type and a wild type strain. Differences in hydrophobic properties were shown at early and late exponential growth phases under microaerobic incubation and at late exponential phase under anaerobiosis.The arcB mutant formed less biofilm than the wild type strain when grown under anaerobic incubation, but displayed higher biofilm formation activity under microaerobic conditions. The adherence to SHA was significantly lower in the mutant when compared with the wild type strain. These results suggest that the transmembrane sensor kinase ArcB, in A. actinomycetemcomitans, senses redox growth conditions and regulates the expression of surface components of the bacterial cell related to biofilm formation and adhesion to saliva coated surfaces. PMID:24031399

  20. Antibacterial activity of moxifloxacin on bacteria associated with periodontitis within a biofilm.

    PubMed

    Tsaousoglou, Phoebus; Nietzsche, Sandor; Cachovan, Georg; Sculean, Anton; Eick, Sigrun

    2014-02-01

    The activity of moxifloxacin was compared with ofloxacin and doxycycline against bacteria associated with periodontitis within a biofilm (single strain and mixed population) in vitro. MICs and minimal bactericidal concentrations (MBCs) of moxifloxacin, ofloxacin and doxycyline were determined against single strains and mixed populations in a planktonic state. Single-species biofilms of two Porphyromonas gingivalis and two Aggregatibacter actinomycetemcomitans strains and a multispecies biofilm consisting of 12 species were formed for 3 days. The minimal biofilm eradication concentrations (MBECs) were determined after exposing the biofilms to the antibacterials (0.002-512 g ml(-1)) for 18 h, addition of nutrient broth for 3 days and subsequent subcultivation. Photographs were taken using confocal laser-scanning microscopy and scanning electron microscopy. The MICs and MBCs did not differ between ofloxacin and moxifloxacin against A. actinomycetemcomitans, whilst moxifloxacin was more active than the other tested antibacterials against anaerobes and the mixed population. The single-species biofilms were eradicated by moderate concentrations of the antibacterials, and the lowest MBECs were always found for moxifloxacin (2-8 g ml(-1)). MBECs against the multispecies biofilms were 128, >512 and >512 g ml(-1) for moxifloxacin, ofloxacin and doxycycline, respectively. In summary, moxifloxacin in a topical formulation may have potential as an adjunct to mechanical removal of the biofilms. PMID:24217128

  1. Adhesion and formation of microbial biofilms in complex microfluidic devices

    SciTech Connect

    Kumar, Aloke; Karig, David K; Neethirajan, Suresh; Suresh, Anil K; Srijanto, Bernadeta R; Mukherjee, Partha P; Retterer, Scott T; Doktycz, Mitchel John

    2012-01-01

    Shewanella oneidensis is a metal reducing bacterium, which is of interest for bioremediation and clean energy applications. S. oneidensis biofilms play a critical role in several situations such as in microbial energy harvesting devices. Here, we use a microfluidic device to quantify the effects of hydrodynamics on the biofilm morphology of S. oneidensis. For different rates of fluid flow through a complex microfluidic device, we studied the spatiotemporal dynamics of biofilms, and we quantified several morphological features such as spatial distribution, cluster formation and surface coverage. We found that hydrodynamics resulted in significant differences in biofilm dynamics. The baffles in the device created regions of low and high flow in the same device. At higher flow rates, a nonuniform biofilm develops, due to unequal advection in different regions of the microchannel. However, at lower flow rates, a more uniform biofilm evolved. This depicts competition between adhesion events, growth and fluid advection. Atomic force microscopy (AFM) revealed that higher production of extra-cellular polymeric substances (EPS) occurred at higher flow velocities.

  2. The effects of changing water flow velocity on the formation of biofilms and water quality in pilot distribution system consisting of copper or polyethylene pipes.

    PubMed

    Lehtola, Markku J; Laxander, Michaela; Miettinen, Ilkka T; Hirvonen, Arja; Vartiainen, Terttu; Martikainen, Pertti J

    2006-06-01

    We studied the effects of flow velocity on the formation of biofilms and the concentration of bacteria in water in copper and plastic (polyethylene, PE) pipes. The formation of biofilms increased with the flow velocity of water. The increase in microbial numbers and contents of ATP was clearer in the PE pipes than in the copper pipes. This was also seen as increased consumption of microbial nutrients in the pipeline system. This indicates that the mass transfer of nutrients is in major role in the growth of biofilms. However, the increased biomass of biofilms did not affect microbial numbers in the water. Rapid changes in water flow rate resuspended biofilms and sediments which increased the concentrations of bacteria and copper in water. The disturbance caused by the changing water flow was also seen as an increase in the particle counts and water turbidity recorded with online instrumentation. PMID:16725175

  3. In situ detection of bacteria in calcified biofilms using FISH and CARD-FISH.

    PubMed

    Shiraishi, Fumito; Zippel, Barbara; Neu, Thomas R; Arp, Gernot

    2008-09-01

    Modified protocols of fluorescence in situ hybridization (FISH) and catalyze reporter deposition fluorescence in situ hybridization (CARD-FISH) were developed in order to detect bacteria in situ in calcified stromatolite biofilms. Smooth, well-preserved thin sections of calcified biofilms (approximately 5 microm thin, vertical sectioning of approximately 1 cm deep) were obtained by cryo-sectioning using the adhesive tape-stabilization technique. A modified hybridization buffer was applied during hybridization to prevent calcite dissolution as well as false binding of oligonucleotide probes to the charged mineral surfaces. Particularly, bright and specific CARD-FISH signals allowed the detection of bacteria in intensively calcified biofilms even at low magnification, which is suitable for investigating millimeter- to centimeter-scale vertical distribution patterns of bacteria. PMID:18571259

  4. Spatial and temporal dynamics of cellulose degradation and biofilm formation by Caldicellulosiruptor obsidiansis and Clostridium thermocellum Caldicellulosiruptor obsidiansis

    SciTech Connect

    Wang, Zhiwu; Lee, Sueng-Hwan; Elkins, James G; Morrell-Falvey, Jennifer L

    2011-01-01

    Cellulose degradation is one of the major bottlenecks of a consolidated bioprocess that employs cellulolytic bacterial cells as catalysts to produce biofuels from cellulosic biomass. In this study, we investigated the spatial and temporal dynamics of cellulose degradation by Caldicellulosiruptor obsidiansis, which does not produce cellulosomes, and Clostridium thermocellum, which does produce cellulosomes. Results showed that the degradation of either regenerated or natural cellulose was synchronized with biofilm formation, a process characterized by the formation and fusion of numerous crater-like depressions on the cellulose surface. In addition, the dynamics of biofilm formation were similar in both bacteria, regardless of cellulosome production. Only the areas of cellulose surface colonized by microbes were significantly degraded, highlighting the essential role of the cellulolytic biofilm in cellulose utilization. After initial attachment, the microbial biofilm structure remained thin, uniform and dense throughout the experiment. A cellular automaton model, constructed under the assumption that the attached cells divide and produce daughter cells that contribute to the hydrolysis of the adjacent cellulose, can largely simulate the observed process of biofilm formation and cellulose degradation. This study presents a model, based on direct observation, correlating cellulolytic biofilm formation with cellulose degradation.

  5. The phylogenetic structure of microbial biofilms and free-living bacteria in a small stream.

    PubMed

    Brablcov, Lenka; Burinkov, Iva; Badurov, Pavlna; Rulk, Martin

    2013-05-01

    The phylogenetic composition, bacterial biomass, and biovolume of both planktonic and biofilm communities were studied in a low-order Byst?ice stream near Olomouc City, in the Czech Republic. The aim of the study was to compare the microbial communities colonizing different biofilm substrata (stream aggregates, stream sediment, underwater tree roots, stream stones, and aquatic macrophytes) to those of free-living bacteria. The phylogenetic composition was analyzed using fluorescence in situ hybridization for main phylogenetic groups. All phylogenetic groups studied were detected in all sample types. The stream stone was the substratum where nearly all phylogenetic groups were the most abundant, while the lowest proportion to the DAPI-stained cells was found for free-living bacteria. The probe specific for the domain Bacteria detected 20.6 to 45.8% of DAPI-stained cells while the probe specific for the domain Archaea detected 4.3 to 17.9%. The most abundant group of Proteobacteria was Alphaproteobacteria with a mean of 14.2%, and the least abundant was Betaproteobacteria with a mean of 11.4%. The average value of the Cytophaga-Flavobacteria group was 10.5%. Total cell numbers and bacterial biomass were highest in sediment and root biofilm. The value of cell biovolume was highest in stone biofilm and lowest in sediment. Overall, this study revealed relevant differences in phylogenetic composition, bacterial biomass, and biovolume between different stream biofilms and free-living bacteria. PMID:23129136

  6. Biofilm-forming bacteria can self-attract by chemotaxis, but only part of the population gets the message

    NASA Astrophysics Data System (ADS)

    Cai, Qiuxian; Ouyang, Qi; Gordon, Vernita

    2015-03-01

    Chemotaxis has been shown to be important for the formation of P. aeruginosa biofilms, but the specific role of chemotaxis in the biofilm-formation process has been unknown. Using a recently-developed microfluidic device for assaying chemotaxis, we show that P. aeruginosa will chemotax towards its own cellular products. This could act to magnify small heterogeneities in density and promote the accumulation of a high density of bacteria, as in a biofilm. The paradigmatic model organism for chemotaxis is E. coli. E. coli has multiple flagella and uses these to swim with a run-and-tumble random walk, biasing its runs towards chemoattractant. However, P. aeruginosa has only a single polar flagellum and therefore in a bulk fluid can only go forward and backward (with small changes in angle possible). This would seem to pose a significant barrier to efficient chemotaxis. We find that the efficiency of P. aeruginosa chemotaxis depends strongly on the initial swimming direction as well as the steepness of the sensed gradient of chemoattractant. Cells swimming up a sufficiently-steep gradient continue going up and do not reverse direction; the remainder show no chemotactally-directed motion. Thus, populations of P. aeruginosa show bimodal response to chemoattractant. Higher levels of chemoattractant increase overall chemotaxis not by increasing swimming speed but by increasing the proportion of bacteria that are in the chemotaxing sub-population.

  7. Novel Multiscale Modeling Tool Applied to Pseudomonas aeruginosa Biofilm Formation

    PubMed Central

    Biggs, Matthew B.; Papin, Jason A.

    2013-01-01

    Multiscale modeling is used to represent biological systems with increasing frequency and success. Multiscale models are often hybrids of different modeling frameworks and programming languages. We present the MATLAB-NetLogo extension (MatNet) as a novel tool for multiscale modeling. We demonstrate the utility of the tool with a multiscale model of Pseudomonas aeruginosa biofilm formation that incorporates both an agent-based model (ABM) and constraint-based metabolic modeling. The hybrid model correctly recapitulates oxygen-limited biofilm metabolic activity and predicts increased growth rate via anaerobic respiration with the addition of nitrate to the growth media. In addition, a genome-wide survey of metabolic mutants and biofilm formation exemplifies the powerful analyses that are enabled by this computational modeling tool. PMID:24147108

  8. The pgaABCD Locus of Escherichia coli Promotes the Synthesis of a Polysaccharide Adhesin Required for Biofilm Formation

    PubMed Central

    Wang, Xin; Preston, James F.; Romeo, Tony

    2004-01-01

    Production of a polysaccharide matrix is a hallmark of bacterial biofilms, but the composition of matrix polysaccharides and their functions are not widely understood. Previous studies of the regulation of Escherichia coli biofilm formation suggested the involvement of an unknown adhesin. We now establish that the pgaABCD (formerly ycdSRQP) locus affects biofilm development by promoting abiotic surface binding and intercellular adhesion. All of the pga genes are required for optimal biofilm formation under a variety of growth conditions. A pga-dependent cell-bound polysaccharide was isolated and determined by nuclear magnetic resonance analyses to consist of unbranched β-1,6-N-acetyl-d-glucosamine, a polymer previously unknown from the gram-negative bacteria but involved in adhesion by staphylococci. The pga genes are predicted to encode envelope proteins involved in synthesis, translocation, and possibly surface docking of this polysaccharide. As predicted, if poly-β-1,6-GlcNAc (PGA) mediates cohesion, metaperiodate caused biofilm dispersal and the release of intact cells, whereas treatment with protease or other lytic enzymes had no effect. The pgaABCD operon exhibits features of a horizontally transferred locus and is present in a variety of eubacteria. Therefore, we propose that PGA serves as an adhesin that stabilizes biofilms of E. coli and other bacteria. PMID:15090514

  9. Occurrence of manganese-oxidizing microorganisms and manganese deposition during biofilm formation on stainless steel in a brackish surface water.

    PubMed

    Kielemoes, Jan; Bultinck, Isabelle; Storms, Hedwig; Boon, Nico; Verstraete, Willy

    2002-01-01

    Abstract Biofilm formation on 316L stainless steel was investigated in a pilotscale flow-through system fed with brackish surface water using an alternating flow/stagnation/flow regime. Microbial community analysis by denaturing gradient gel electrophoresis and sequencing revealed the presence of complex microbial ecosystems consisting of, amongst others, Leptothrix-related manganese-oxidizing bacteria in the adjacent water, and sulfur-oxidizing, sulfate-reducing and slime-producing bacteria in the biofilm. Selective plating of the biofilm indicated the presence of high levels of manganese-oxidizing microorganisms, while microscopic and chemical analyses of the biofilm confirmed the presence of filamentous manganese-precipitating microorganisms, most probably Leptothrix species. Strong accumulation of iron and manganese occurred in the biofilm relative to the adjacent water. No evidence of selective colonization of the steel surface or biocorrosion was found over the experimental period. The overall results of this study highlight the potential formation of complex microbial biofilm communities in flow-through systems thriving on minor concentrations of manganese. PMID:19709183

  10. Staphylococcus epidermidis in Orthopedic Device Infections: The Role of Bacterial Internalization in Human Osteoblasts and Biofilm Formation

    PubMed Central

    Valour, Florent; Trouillet-Assant, Sophie; Rasigade, Jean-Philippe; Lustig, Sbastien; Chanard, Emmanuel; Meugnier, Hlne; Tigaud, Sylvestre; Vandenesch, Franois; Etienne, Jrome; Ferry, Tristan; Laurent, Frdric

    2013-01-01

    Background Staphylococcus epidermidis orthopedic device infections are caused by direct inoculation of commensal flora during surgery and remain rare, although S. epidermidis carriage is likely universal. We wondered whether S. epidermidis orthopedic device infection strains might constitute a sub-population of commensal isolates with specific virulence ability. Biofilm formation and invasion of osteoblasts by S. aureus contribute to bone and joint infection recurrence by protecting bacteria from the host-immune system and most antibiotics. We aimed to determine whether S. epidermidis orthopedic device infection isolates could be distinguished from commensal strains by their ability to invade osteoblasts and form biofilms. Materials and Methods Orthopedic device infection S. epidermidis strains (n?=?15) were compared to nasal carriage isolates (n?=?22). Osteoblast invasion was evaluated in an ex vivo infection model using MG63 osteoblastic cells co-cultured for 2 hours with bacteria. Adhesion of S. epidermidis to osteoblasts was explored by a flow cytometric approach, and internalized bacteria were quantified by plating cell lysates after selective killing of extra-cellular bacteria with gentamicin. Early and mature biofilm formations were evaluated by a crystal violet microtitration plate assay and the Biofilm Ring Test method. Results No difference was observed between commensal and infective strains in their ability to invade osteoblasts (internalization rate 308+/?631 and 347+/?431 CFU/well, respectively). This low internalization rate correlated with a low ability to adhere to osteoblasts. No difference was observed for biofilm formation between the two groups. Conclusion Osteoblast invasion and biofilm formation levels failed to distinguish S. epidermidis orthopedic device infection strains from commensal isolates. This study provides the first assessment of the interaction between S. epidermidis strains isolated from orthopedic device infections and osteoblasts, and suggests that bone cell invasion is not a major pathophysiological mechanism in S. epidermidis orthopedic device infections, contrary to what is observed for S. aureus. PMID:23840636

  11. Biofilm formation by coagulase-negative staphylococci: impact on the efficacy of antimicrobials and disinfectants commonly used on dairy farms.

    PubMed

    Tremblay, Yannick D N; Caron, Vincent; Blondeau, Andréanne; Messier, Serge; Jacques, Mario

    2014-08-27

    Coagulase-negative staphylococci (CNS) have traditionally been considered minor mastitis pathogens and are the bacteria most frequently isolated from intramammary infection. Previously, our laboratory demonstrated that a majority of CNS isolated from Canadian milk were able to form biofilm and this was strongly and positively associated with days in milk. Biofilms offer protection against antibiotics and disinfectants, and the presence of CNS biofilms near the end of the lactation cycle could have an impact on the prevention and recurrence of CNS infections in the next lactation cycle. The objective of this study was to investigate the effect of biofilm formation on efficacy of commonly used antibiotics and disinfectants against CNS. The minimal inhibitory concentration (MIC) and minimal biofilm eradication concentration (MBEC) of several CNS isolates were determined using microdilution method and the MBEC device, respectively. Biofilm cells were more resistant to a penicillin G/novobiocin combination and to ceftiofur than their planktonic counterparts and the increase in resistance ranged from 4× to 2048×. For the disinfectants, we determined the minimum contact time required for different teat disinfectants to eradicated planktonic cells and biofilms. The chlorhexidine-based teat disinfectants eradicated planktonic cells and biofilms within 30s. For iodine-based teat disinfectants, it took 2-10× longer to eradicate the biofilms than planktonic cells. In conclusion, CNS biofilms were less susceptible to antibiotics; however, chlorhexidine-based teat disinfectants were still effective against CNS biofilms. This reinforces the use of post-milking teat disinfectants as a preventive measure of intramammary infections. PMID:24984943

  12. N-acetyl-L-cysteine affects growth, extracellular polysaccharide production, and bacterial biofilm formation on solid surfaces.

    PubMed

    Olofsson, Ann-Cathrin; Hermansson, Malte; Elwing, Hans

    2003-08-01

    N-Acetyl-L-cysteine (NAC) is used in medical treatment of patients with chronic bronchitis. The positive effects of NAC treatment have primarily been attributed to the mucus-dissolving properties of NAC, as well as its ability to decrease biofilm formation, which reduces bacterial infections. Our results suggest that NAC also may be an interesting candidate for use as an agent to reduce and prevent biofilm formation on stainless steel surfaces in environments typical of paper mill plants. Using 10 different bacterial strains isolated from a paper mill, we found that the mode of action of NAC is chemical, as well as biological, in the case of bacterial adhesion to stainless steel surfaces. The initial adhesion of bacteria is dependent on the wettability of the substratum. NAC was shown to bind to stainless steel, increasing the wettability of the surface. Moreover, NAC decreased bacterial adhesion and even detached bacteria that were adhering to stainless steel surfaces. Growth of various bacteria, as monocultures or in a multispecies community, was inhibited at different concentrations of NAC. We also found that there was no detectable degradation of extracellular polysaccharides (EPS) by NAC, indicating that NAC reduced the production of EPS, in most bacteria tested, even at concentrations at which growth was not affected. Altogether, the presence of NAC changes the texture of the biofilm formed and makes NAC an interesting candidate for use as a general inhibitor of formation of bacterial biofilms on stainless steel surfaces. PMID:12902275

  13. Effect of eel galectin AJL-1 on periodontopathic bacterial biofilm formation and their lipopolysaccharide-mediated inflammatory cytokine induction.

    PubMed

    Takayama, Saori; Saitoh, Eiichi; Kimizuka, Ryuta; Yamada, Satoru; Kato, Tetsuo

    2009-10-01

    Porphyromonas gingivalis, Prevotella intermedia and Aggregatibacter actinomycetemcomitans, infectious pathogenic bacteria found in oral biofilm, cause periodontal disease. The inhibitory effect of AJL-1, a galectin present in the skin mucus of the Japanese eel Anguilla japonica, on biofilm formation by each of these strains was investigated by staining adherent bacteria on culture plates with crystal violet. An ATP bioluminescence assay was used to determine whether inhibition of biofilm formation was due to the bactericidal activity of AJL-1. The effect of AJL-1 on cytokine induction in human umbilical vascular endothelial cells (HUVECs) by lipopolysaccharide (LPS) isolated from A. actinomycetemcomitans was also investigated by enzyme-linked immunosorbent assay (ELISA). AJL-1 significantly inhibited biofilm formation by A. actinomycetemcomitans strains Y4, ATCC 29523 and ATCC 29524 but not by any strain of P. gingivalis or P. intermedia, and showed no bactericidal activity against A. actinomycetemcomitans strains. AJL-1 markedly suppressed interleukin (IL)-6 and IL-8 induction in HUVECs by LPS from A. actinomycetemcomitans strains Y4 and ATCC 29523. These observations indicate that AJL-1 is an effective inhibitor of biofilm formation by A. actinomycetemcomitans as well as of inflammatory cytokine induction in HUVECs by LPS. These finding indicate that AJL-1 may be of therapeutic value in A. actinomycetemcomitans-associated periodontal diseases. PMID:19505801

  14. Revised paradigm of aquatic biofilm formation facilitated by microgel transparent exopolymer particles

    PubMed Central

    Bar-Zeev, Edo; Berman-Frank, Ilana; Girshevitz, Olga; Berman, Tom

    2012-01-01

    Transparent exopolymer particles (TEPs) are planktonic, organic microgels that are ubiquitous in aqueous environments. Increasing evidence indicates that TEPs play an active role in the process of aquatic biofilm formation. Frequently, TEPs are intensely colonized by bacteria and other microorganisms, thus serving as hot spots of intense microbial activity. We introduce the term protobiofilm to refer to TEPs with extensive microbial outgrowth and colonization. Such particles display most of the characteristics of developing biofilm, with the exception of being attached to a surface. In this study, coastal seawater was passed through custom-designed flow cells that enabled direct observation of TEPs and protobiofilm in the feedwater stream by bright-field and epifluorescence microscopy. Additionally, we could follow biofilm development on immersed surfaces inside the flow cells. Within minutes, we observed TEP and protobiofilm patches adhering to these surfaces. By 30 min, confocal laser-scanning microscopy (CLSM) revealed numerous patches of Con A and SYTO 9 staining structures covering the surfaces. Atomic force microscopy showed details of a thin, highly sticky, organic conditioning layer between these patches. Bright-field and epifluorescence microscopy and CLSM showed that biofilm development (observed until 24 h) was profoundly inhibited in flow cells with seawater prefiltered to remove most large TEPs and protobiofilm. We propose a revised paradigm for aquatic biofilm development that emphasizes the critical role of microgel particles such as TEPs and protobiofilm in facilitating this process. Recognition of the role of planktonic microgels in aquatic biofilm formation can have applied importance for the water industry. PMID:22615362

  15. Iron is a signal for Stenotrophomonas maltophilia biofilm formation, oxidative stress response, OMPs expression, and virulence

    PubMed Central

    García, Carlos A.; Alcaraz, Eliana S.; Franco, Mirta A.; Passerini de Rossi, Beatriz N.

    2015-01-01

    Stenotrophomonas maltophilia is an emerging nosocomial pathogen. In many bacteria iron availability regulates, through the Fur system, not only iron homeostasis but also virulence. The aim of this work was to assess the role of iron on S. maltophilia biofilm formation, EPS production, oxidative stress response, OMPs regulation, quorum sensing (QS), and virulence. Studies were done on K279a and its isogenic fur mutant F60 cultured in the presence or absence of dipyridyl. This is the first report of spontaneous fur mutants obtained in S. maltophilia. F60 produced higher amounts of biofilms than K279a and CLSM analysis demonstrated improved adherence and biofilm organization. Under iron restricted conditions, K279a produced biofilms with more biomass and enhanced thickness. In addition, F60 produced higher amounts of EPS than K279a but with a similar composition, as revealed by ATR-FTIR spectroscopy. With respect to the oxidative stress response, MnSOD was the only SOD isoenzyme detected in K279a. F60 presented higher SOD activity than the wt strain in planktonic and biofilm cultures, and iron deprivation increased K279a SOD activity. Under iron starvation, SDS-PAGE profile from K279a presented two iron-repressed proteins. Mass spectrometry analysis revealed homology with FepA and another putative TonB-dependent siderophore receptor of K279a. In silico analysis allowed the detection of potential Fur boxes in the respective coding genes. K279a encodes the QS diffusible signal factor (DSF). Under iron restriction K279a produced higher amounts of DSF than under iron rich condition. Finally, F60 was more virulent than K279a in the Galleria mellonella killing assay. These results put in evidence that iron levels regulate, likely through the Fur system, S. maltophilia biofilm formation, oxidative stress response, OMPs expression, DSF production and virulence. PMID:26388863

  16. Iron is a signal for Stenotrophomonas maltophilia biofilm formation, oxidative stress response, OMPs expression, and virulence.

    PubMed

    Garca, Carlos A; Alcaraz, Eliana S; Franco, Mirta A; Passerini de Rossi, Beatriz N

    2015-01-01

    Stenotrophomonas maltophilia is an emerging nosocomial pathogen. In many bacteria iron availability regulates, through the Fur system, not only iron homeostasis but also virulence. The aim of this work was to assess the role of iron on S. maltophilia biofilm formation, EPS production, oxidative stress response, OMPs regulation, quorum sensing (QS), and virulence. Studies were done on K279a and its isogenic fur mutant F60 cultured in the presence or absence of dipyridyl. This is the first report of spontaneous fur mutants obtained in S. maltophilia. F60 produced higher amounts of biofilms than K279a and CLSM analysis demonstrated improved adherence and biofilm organization. Under iron restricted conditions, K279a produced biofilms with more biomass and enhanced thickness. In addition, F60 produced higher amounts of EPS than K279a but with a similar composition, as revealed by ATR-FTIR spectroscopy. With respect to the oxidative stress response, MnSOD was the only SOD isoenzyme detected in K279a. F60 presented higher SOD activity than the wt strain in planktonic and biofilm cultures, and iron deprivation increased K279a SOD activity. Under iron starvation, SDS-PAGE profile from K279a presented two iron-repressed proteins. Mass spectrometry analysis revealed homology with FepA and another putative TonB-dependent siderophore receptor of K279a. In silico analysis allowed the detection of potential Fur boxes in the respective coding genes. K279a encodes the QS diffusible signal factor (DSF). Under iron restriction K279a produced higher amounts of DSF than under iron rich condition. Finally, F60 was more virulent than K279a in the Galleria mellonella killing assay. These results put in evidence that iron levels regulate, likely through the Fur system, S. maltophilia biofilm formation, oxidative stress response, OMPs expression, DSF production and virulence. PMID:26388863

  17. Bacteriophage Cocktail for the Prevention of Biofilm Formation by Pseudomonas aeruginosa on Catheters in an In Vitro Model System?

    PubMed Central

    Fu, Weiling; Forster, Terri; Mayer, Oren; Curtin, John J.; Lehman, Susan M.; Donlan, Rodney M.

    2010-01-01

    Microorganisms develop biofilms on indwelling medical devices and are associated with device-related infections, resulting in substantial morbidity and mortality. This study investigated the effect of pretreating hydrogel-coated catheters with Pseudomonas aeruginosa bacteriophages on biofilm formation by P. aeruginosa in an in vitro model. Hydrogel-coated catheters were exposed to a 10 log10 PFU ml?1 lysate of P. aeruginosa phage M4 for 2 h at 37C prior to bacterial inoculation. The mean viable biofilm count on untreated catheters was 6.87 log10 CFU cm?2 after 24 h. The pretreatment of catheters with phage reduced this value to 4.03 log10 CFU cm?2 (P < 0.001). Phage treatment immediately following bacterial inoculation also reduced biofilm viable counts (4.37 log10 CFU cm?2 reduction; P < 0.001). The regrowth of biofilms on phage-treated catheters occurred between 24 and 48 h, but supplemental treatment with phage at 24 h significantly reduced biofilm regrowth (P < 0.001). Biofilm isolates resistant to phage M4 were recovered from catheters pretreated with phage. The phage susceptibility profiles of these isolates were used to guide the development of a five-phage cocktail from a larger library of P. aeruginosa phages. The pretreatment of catheters with this cocktail reduced the 48-h mean biofilm cell density by 99.9% (from 7.13 to 4.13 log10 CFU cm?2; P < 0.001), but fewer biofilm isolates were resistant to these phages. These results suggest the potential of applying phages, especially phage cocktails, to the surfaces of indwelling medical devices for mitigating biofilm formation by clinically relevant bacteria. PMID:19822702

  18. EmbRS a new two-component system that inhibits biofilm formation and saves Rubrivivax gelatinosus from sinking

    PubMed Central

    Steunou, Anne Soisig; Liotenberg, Sylviane; Soler, Marie-Nolle; Briandet, Romain; Barbe, Valrie; Astier, Chantal; Ouchane, Soufian

    2013-01-01

    Photosynthetic bacteria can switch from planktonic lifestyle to phototrophic biofilm in mats in response to environmental changes. The mechanisms of phototrophic biofilm formation are, however, not characterized. Herein, we report a two-component system EmbRS that controls the biofilm formation in a photosynthetic member of the Burkholderiales order, the purple bacterium Rubrivivax gelatinosus. EmbRS inactivation results in cells that form conspicuous bacterial veils and fast-sinking aggregates in liquid. Biofilm analyses indicated that EmbRS represses the production of an extracellular matrix and biofilm formation. Mapping of transposon mutants that partially or completely restore the wild-type (WT) phenotype allowed the identification of two gene clusters involved in polysaccharide synthesis, one fully conserved only in Thauera sp., a floc-forming wastewater bacterium. A second two-component system BmfRS and a putative diguanylate cyclase BdcA were also identified in this screen suggesting their involvement in biofilm formation in this bacterium. The role of polysaccharides in sinking of microorganisms and organic matter, as well as the importance and the evolution of such regulatory system in phototrophic microorganisms are discussed. PMID:23520142

  19. EmbRS a new two-component system that inhibits biofilm formation and saves Rubrivivax gelatinosus from sinking.

    PubMed

    Steunou, Anne Soisig; Liotenberg, Sylviane; Soler, Marie-Nolle; Briandet, Romain; Barbe, Valrie; Astier, Chantal; Ouchane, Soufian

    2013-06-01

    Photosynthetic bacteria can switch from planktonic lifestyle to phototrophic biofilm in mats in response to environmental changes. The mechanisms of phototrophic biofilm formation are, however, not characterized. Herein, we report a two-component system EmbRS that controls the biofilm formation in a photosynthetic member of the Burkholderiales order, the purple bacterium Rubrivivax gelatinosus. EmbRS inactivation results in cells that form conspicuous bacterial veils and fast-sinking aggregates in liquid. Biofilm analyses indicated that EmbRS represses the production of an extracellular matrix and biofilm formation. Mapping of transposon mutants that partially or completely restore the wild-type (WT) phenotype allowed the identification of two gene clusters involved in polysaccharide synthesis, one fully conserved only in Thauera sp., a floc-forming wastewater bacterium. A second two-component system BmfRS and a putative diguanylate cyclase BdcA were also identified in this screen suggesting their involvement in biofilm formation in this bacterium. The role of polysaccharides in sinking of microorganisms and organic matter, as well as the importance and the evolution of such regulatory system in phototrophic microorganisms are discussed. PMID:23520142

  20. Inhibition of Gallic Acid on the Growth and Biofilm Formation of Escherichia coli and Streptococcus mutans.

    PubMed

    Shao, Dongyan; Li, Jing; Li, Ji; Tang, Ruihua; Liu, Liu; Shi, Junling; Huang, Qingsheng; Yang, Hui

    2015-06-01

    New strategies for biofilm inhibition are becoming highly necessary because of the concerns to synthetic additives. As gallic acid (GA) is a hydrolysated natural product of tannin in Chinese gall, this research studied the effects of GA on the growth and biofilm formation of bacteria (Escherichia coli [Gram-negative] and Streptococcus mutans [Gram-positive]) under different conditions, such as nutrient levels, temperatures (25 and 37C) and incubation times (24 and 48h). The minimum antimicrobial concentration of GA against the two pathogenic organisms was determined as 8mg/mL. GA significantly affected the growth curves of both test strains at 25 and 37C. The nutrient level, temperature, and treatment time influenced the inhibition activity of GA on both growth and biofim formation of tested pathogens. The inhibition effect of GA on biofilm could be due to other factors in addition to the antibacterial effect. Overall, GA was most effective against cultures incubated at 37C for 24h and at 25C for 48h in various concentrations of nutrients and in vegetable wash waters, which indicated the potential of GA as emergent sources of biofilm control products. PMID:25974286

  1. Biofilm formation by strains of Leuconostoc citreum and L. mesenteroides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: To compare for the first time biofilm formation among strains of Leuconostoc citreum and L. mesenteroides that produce varying types of extracellular glucans. Methods and Results: Twelve strains of Leuconostoc sp. that produce extracellular glucans were compared for their capacity to produ...

  2. BACTERIAL BIOFILM FORMATION UNDER MICROGRAVITY CONDITIONS. (R825503)

    EPA Science Inventory

    Although biofilm formation is widely documented on Earth, it has not been demonstrated in the absence of gravity. To explore this possibility, Pseudomonas aeruginosa, suspended in sterile buffer, was flown in a commercial payload on space shuttle flight STS-95. During earth or...

  3. Influence of Calcium in Extracellular DNA Mediated Bacterial Aggregation and Biofilm Formation

    PubMed Central

    Koop, Leena; Wong, Yie Kuan; Ahmed, Safia; Siddiqui, Khawar Sohail; Manefield, Mike

    2014-01-01

    Calcium (Ca2+) has an important structural role in guaranteeing the integrity of the outer lipopolysaccharide layer and cell walls of bacterial cells. Extracellular DNA (eDNA) being part of the slimy matrix produced by bacteria promotes biofilm formation through enhanced structural integrity of the matrix. Here, the concurrent role of Ca2+ and eDNA in mediating bacterial aggregation and biofilm formation was studied for the first time using a variety of bacterial strains and the thermodynamics of DNA to Ca2+ binding. It was found that the eDNA concentrations under both planktonic and biofilm growth conditions were different among bacterial strains. Whilst Ca2+ had no influence on eDNA release, presence of eDNA by itself favours bacterial aggregation via attractive acid-base interactions in addition, its binding with Ca2+ at biologically relevant concentrations was shown further increase in bacterial aggregation via cationic bridging. Negative Gibbs free energy (?G) values in iTC data confirmed that the interaction between DNA and Ca2+ is thermodynamically favourable and that the binding process is spontaneous and exothermic owing to its highly negative enthalpy. Removal of eDNA through DNase I treatment revealed that Ca2+ alone did not enhance cell aggregation and biofilm formation. This discovery signifies the importance of eDNA and concludes that existence of eDNA on bacterial cell surfaces is a key facilitator in binding of Ca2+ to eDNA thereby mediating bacterial aggregation and biofilm formation. PMID:24651318

  4. Bacillus mojavensis biofilm formation and biosurfactant production using a Laser Ablation Electrospray Ionization System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofilms are important extracellular polymeric compounds produced by bacteria that are useful for developmental phases including motility, swarming, signaling processes, and for hydrophobic nutrient utilization, all of which are important attributes for endophytic bacteria with biocontrol potential....

  5. Visualizing biofilm formation in endotracheal tubes using endoscopic three-dimensional optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Heidari, Andrew E.; Moghaddam, Samer; Troung, Kimberly K.; Chou, Lidek; Genberg, Carl; Brenner, Matthew; Chen, Zhongping

    2015-12-01

    Biofilm formation has been linked to ventilator-associated pneumonia, which is a prevalent infection in hospital intensive care units. Currently, there is no rapid diagnostic tool to assess the degree of biofilm formation or cellular biofilm composition. Optical coherence tomography (OCT) is a minimally invasive, nonionizing imaging modality that can be used to provide high-resolution cross-sectional images. Biofilm deposited in critical care patients' endotracheal tubes was analyzed in vitro. This study demonstrates that OCT could potentially be used as a diagnostic tool to analyze and assess the degree of biofilm formation and extent of airway obstruction caused by biofilm in endotracheal tubes.

  6. The Relative Contributions of Physical Structure and Cell Density to the Antibiotic Susceptibility of Bacteria in Biofilms

    PubMed Central

    Kirby, Amy E.; Garner, Kimberly

    2012-01-01

    For many bacterial infections, noninherited mechanisms of resistance are responsible for extending the term of treatment and in some cases precluding its success. Among the most important of these noninherited mechanisms of resistance is the ability of bacteria to form biofilms. There is compelling evidence that bacteria within biofilms are more refractory to antibiotics than are planktonic cells. Not so clear, however, is the extent to which this resistance can be attributed to the structure of biofilms rather than the physiology and density of bacteria within them. To explore the contribution of the structure of biofilms to resistance in a quantitative way, we developed an assay that compares the antibiotic sensitivity of bacteria in biofilms to cells mechanically released from these structures. Our method, which we apply to Escherichia coli and Staphylococcus aureus each with antibiotics of five classes, controls for the density and physiological state of the treated bacteria. For most of the antibiotics tested, the bacteria in biofilms were no more resistant than the corresponding populations of planktonic cells of similar density. Our results, however, suggest that killing by gentamicin, streptomycin, and colistin is profoundly inhibited by the structure of biofilms; these drugs are substantially more effective in killing bacteria released from biofilms than cells within these structures. PMID:22450987

  7. Bacterial growth and biofilm formation in household-stored groundwater collected from public wells.

    PubMed

    Burkowska-But, Aleksandra; Kalwasi?ska, Agnieszka; Swiontek Brzezinska, Maria

    2015-06-01

    The research was aimed at assessing changes in the number of bacteria and evaluating biofilm formation in groundwater collected from public wells, both aspects directly related to the methods of household storage. In the research, water collected from Cretaceous aquifer wells in Toru? (Poland) was stored in a refrigerator and at room temperature. Microbiological parameters of the water were measured immediately after the water collection, and then after 3 and 7 days of storage under specified conditions. The microbiological examination involved determining the number of heterotrophic bacteria capable of growth at 22 and 37 C, the number of spore-forming bacteria, and the total number of bacteria on membrane filters. The storage may affect water quality to such an extent that the water, which initially met the microbiological criteria for water intended for human consumption, may pose a health risk. The repeated use of the same containers for water storage results in biofilm formation containing live and metabolically active bacterial cells. PMID:26042968

  8. Immobilization of Rhodococcus rhodochrous BX2 (an acetonitrile-degrading bacterium) with biofilm-forming bacteria for wastewater treatment.

    PubMed

    Li, Chunyan; Li, Yue; Cheng, Xiaosong; Feng, Liping; Xi, Chuanwu; Zhang, Ying

    2013-03-01

    In this study, a unique biofilm consisting of three bacterial strains with high biofilm-forming capability (Bacillus subtilis E2, E3, and N4) and an acetonitrile-degrading bacterium (Rhodococcus rhodochrous BX2) was established for acetonitrile-containing wastewater treatment. The results indicated that this biofilm exhibited strong resistance to acetonitrile loading shock and displayed a typical spatial and structural heterogeneity and completely depleted the initial concentration of acetonitrile (800mgL(-1)) within 24h in a moving-bed-biofilm reactor (MBBR) after operation for 30days. The immobilization of BX2 cells in the biofilm was confirmed by PCR-DGGE. It has been demonstrated that biofilm-forming bacteria can promote the immobilization of contaminant-degrading bacteria in the biofilms and can subsequently improve the degradation of contaminants in wastewater. This approach offers a novel strategy for enhancing biological oxidation of toxic pollutants in wastewater. PMID:23376196

  9. Impact of TiO2 Nanoparticles on Growth, Biofilm Formation, and Flavin Secretion in Shewanella oneidensis

    PubMed Central

    Maurer-Jones, Melissa A.; Gunsolus, Ian L.; Meyer, Ben M.; Christenson, Cole J.; Haynes, Christy L.

    2013-01-01

    Understanding of nanoparticle impacts on critical bacteria functions allows us to gain a mechanistic understanding of toxicity and guides us towards design rules for creating safe nanomaterials. Herein and using analytical techniques, biofilm formation, a general bacteria function, and riboflavin secretion, a species-specific function, were monitored in Shewanella oneidensis, a metal reducing bacterium, following exposure to a variety of TiO2 nanoparticle types (synthesized, Aeroxide P25, and T-Eco). TEM images show that dosed nanoparticles are in close proximity to the bacteria but they are not internalized. Using quartz crystal microbalance (QCM), it was revealed that S. oneidensis biofilm formation is slowed in the presence of nanoparticles. Though S. oneidensis grows more slowly in the presence of TiO2 nanoparticles, riboflavin secretion, a function related to the S. oneidensis metal reducing capacity, was increased significantly in a nanoparticle dose-dependent manner. Both changes in biofilm formation and riboflavin secretion are supported by changes in gene expression in nanoparticle-exposed S. oneidensis. This broad study of bacterial nanotoxicity, including use of sensitive analytical tools for functional assessments of biofilm formation, riboflavin secretion, and gene expression has implications for total ecosystem health as the use of engineered nanoparticles grows. PMID:23701037

  10. Community structure analysis of reverse osmosis membrane biofilms and the significance of Rhizobiales bacteria in biofouling.

    PubMed

    Pang, Chee Meng; Liu, Wen-Tso

    2007-07-01

    The biofilm community structure of a biofouled reverse osmosis (RO) membrane was examined using a polyphasic approach, and the dominant phylotypes retrieved were related to the order Rhizobiales, a group of bacteria that is hitherto not implicated in membrane biofouling. A comparison with two other membrane biofilms using T-RFLP fingerprinting also revealed the dominance of Rhizobiales organisms. When pure culture RO biofilm isolates were cultivated aerobically in BIOLOG microplates, most Rhizobiales were metabolically versatile in their choice of carbon substrates. Nitrate reduction was observed in five RO isolates related to Castellaniella, Ochrobactrum, Stenotrophomonas, and Xanthobacter. Many of the key Rhizobiales genera including Bosea, Ochrobactrum, Shinella, and Rhodopseudomonas were detected by PCR to contain the nirK gene responsible for nitrite reductase activity. These findings suggest that Rhizobiales organisms are ecologically significant in membrane biofilm communities under both aerobic and anoxic conditions and may be responsible for biofouling in membrane separation systems. PMID:17695921

  11. [The effect of mutations in the synthesis of lipopolysaccharides and calcofluor-binding polysaccharides on biofilm formation by Azospirillum brasilense].

    PubMed

    Shelud'ko, A V; Kulibiakina, O V; Shirokov, A A; Petrova, L P; Matora, L Iu; Katsy, E I

    2008-01-01

    The thickness and antigenic properties of biofilms produced by Azospirillum brasilense Sp245 and its mutants deficient in the synthesis of lipopolysaccharides (Lps) and calcofluor-binding polysaccharides (CBPS) at the interface between water and hydrophilic or hydrophobic solid surfaces were compared. The mutants deficient in acidic LpsI synthesis produce thicker biofilms on hydrophilic surfaces. Biofilms produced on hydrophobic surfaces by bacteria that are unable to synthesize CBPS are less pronounced. Defects in CBPS production in Azospirillum mutants with impaired flagellar motility can cause adverse effects on the cell ability to attach to hydrophobic and hydrophilic surfaces. The loss of the neutral LpsII antigen by the mutants capable of producing CBPS does not affect their behavior on hydrophobic surfaces, which is probably due to the compensatory increase in the total polysaccharide production. The fundamental change in the Lps structure correlates with the activation of biofilm formation by the relevant mutants on hydrophilic and hydrophobic surfaces. PMID:18683653

  12. Regulation of biofilm formation in Salmonella enterica serovar Typhimurium.

    PubMed

    Simm, Roger; Ahmad, Irfan; Rhen, Mikael; Le Guyon, Soazig; Römling, Ute

    2014-01-01

    In animals, plants and the environment, Salmonella enterica serovar Typhimurium forms the red dry and rough (rdar) biofilm characterized by extracellular matrix components curli and cellulose. With complex expression control by at least ten transcription factors, the bistably expressed orphan response regulator CsgD directs rdar morphotype development. CsgD expression is an integral part of the Hfq regulon and the complex cyclic diguanosine monophosphate signaling network partially controlled by the global RNA-binding protein CsrA. Cell wall turnover and the periplasmic redox status regulate csgD expression on a post-transcriptional level by unknown mechanisms. Furthermore, phosphorylation of CsgD is a potential inactivation and degradation signal in biofilm dissolution. Including complex incoherent feed-forward loops, regulation of biofilm formation versus motility and virulence is of recognized complexity. PMID:25437188

  13. Antibiotic Resistance Related to Biofilm Formation in Klebsiella pneumoniae

    PubMed Central

    Vuotto, Claudia; Longo, Francesca; Balice, Maria Pia; Donelli, Gianfranco; Varaldo, Pietro E.

    2014-01-01

    The Gram-negative opportunistic pathogen, Klebsiella pneumoniae, is responsible for causing a spectrum of community-acquired and nosocomial infections and typically infects patients with indwelling medical devices, especially urinary catheters, on which this microorganism is able to grow as a biofilm. The increasingly frequent acquisition of antibiotic resistance by K. pneumoniae strains has given rise to a global spread of this multidrug-resistant pathogen, mostly at the hospital level. This scenario is exacerbated when it is noted that intrinsic resistance to antimicrobial agents dramatically increases when K. pneumoniae strains grow as a biofilm. This review will summarize the findings about the antibiotic resistance related to biofilm formation in K. pneumoniae. PMID:25438022

  14. Characterization of Biofilm Formation and the Role of BCR1 in Clinical Isolates of Candida parapsilosis

    PubMed Central

    Pannanusorn, Srisuda; Ramrez-Zavala, Bernardo; Lnsdorf, Heinrich; Agerberth, Birgitta; Morschhuser, Joachim

    2014-01-01

    In Candida parapsilosis, biofilm formation is considered to be a major virulence factor. Previously, we determined the ability of 33 clinical isolates causing bloodstream infection to form biofilms and identified three distinct groups of biofilm-forming strains (negative, low, and high). Here, we establish two different biofilm structures among strains forming large amounts of biofilm in which strains with complex spider-like structures formed robust biofilms on different surface materials with increased resistance to fluconazole. Surprisingly, the transcription factor Bcr1, required for biofilm formation in Candida albicans and C. parapsilosis, has an essential role only in strains with low capacity for biofilm formation. Although BCR1 leads to the formation of more and longer pseudohyphae, it was not required for initial adhesion and formation of mature biofilms in strains with a high level of biofilm formation. Furthermore, an additional phenotype affected by BCR1 was the switch in colony morphology from rough to crepe, but only in strains forming high levels of biofilm. All bcr1?/? mutants showed increased proteolytic activity and increased susceptibility to the antimicrobial peptides protamine and RP-1 compared to corresponding wild-type and complemented strains. Taken together, our results demonstrate that biofilm formation in clinical isolates of C. parapsilosis is both dependent and independent of BCR1, but even in strains which showed a BCR1-independent biofilm phenotype, BCR1 has alternative physiological functions. PMID:24297446

  15. Effect of biofilm formation, and biocorrosion on denture base fractures

    PubMed Central

    Ergin, Alper; Ayyildiz, Simel; Cosgun, Erdal; Uzun, Gulay

    2013-01-01

    PURPOSE The aim of this study was to investigate the destructive effects of biofilm formation and/or biocorrosive activity of 6 different oral microorganisms. MATERIALS AND METHODS Three different heat polymerized acrylic resins (Ivocap Plus, Lucitone 550, QC 20) were used to prepare three different types of samples. Type "A" samples with "V" type notch was used to measure the fracture strength, "B" type to evaluate the surfaces with scanning electron microscopy and "C" type for quantitative biofilm assay. Development and calculation of biofilm covered surfaces on denture base materials were accomplished by SEM and quantitative biofilm assay. According to normality assumptions ANOVA or Kruskal-Wallis was selected for statistical analysis (?=0.05). RESULTS Significant differences were obtained among the adhesion potential of 6 different microorganisms and there were significant differences among their adhesion onto 3 different denture base materials. Compared to the control groups after contamination with the microorganisms, the three point bending test values of denture base materials decreased significantly (P<.05); microorganisms diffused at least 52% of the denture base surface. The highest median quantitative biofilm value within all the denture base materials was obtained with P. aeruginosa on Lucitone 550. The type of denture base material did not alter the diffusion potential of the microorganisms significantly (P>.05). CONCLUSION All the tested microorganisms had destructive effect over the structure and composition of the denture base materials. PMID:23755339

  16. Molecular basis of in-vivo biofilm formation by bacterial pathogens

    PubMed Central

    Joo, Hwang-Soo; Otto, Michael

    2012-01-01

    Summary Bacterial biofilms are involved in a multitude of serious chronic infections. In recent years, modeling biofilm infection in vitro led to the identification of microbial determinants governing biofilm development. However, we lack information as to whether biofilm formation mechanisms identified in vitro have relevance for biofilm-associated infection. Here, we discuss the molecular basis of biofilm formation using staphylococci and Pseudomonas aeruginosa to illustrate key points, as their biofilm development process is well-studied. We will focus on in-vivo findings such as obtained in animal infection models, and critically evaluate in-vivo relevance of in-vitro findings. Although results on the role of quorum-sensing in biofilm formation have been conflicting, we now argue that integration of in-vitro and in-vivo studies allows a differentiated view of this mechanism as it relates to biofilm infection. PMID:23261595

  17. Polyphosphate Degradation in Stationary Phase Triggers Biofilm Formation via LuxS Quorum Sensing System in Escherichia coli

    PubMed Central

    Grillo-Puertas, Mariana; Villegas, Josefina M.; Rintoul, Mara R.; Rapisarda, Viviana A.

    2012-01-01

    In most natural environments, association with a surface in a structure known as biofilm is the prevailing microbial life-style of bacteria. Polyphosphate (polyP), an ubiquitous linear polymer of hundreds of orthophosphate residues, has a crucial role in stress responses, stationary-phase survival, and it was associated to bacterial biofilm formation and production of virulence factors. In previous work, we have shown that Escherichia coli cells grown in media containing a critical phosphate concentration >37 mM maintained an unusual high polyP level in stationary phase. The aim of the present work was to analyze if fluctuations in polyP levels in stationary phase affect biofilm formation capacity in E. coli. Polymer levels were modulated by the media phosphate concentration or using mutant strains in polyP metabolism. Cells grown in media containing phosphate concentrations higher than 25 mM were defective in biofilm formation. Besides, there was a disassembly of 24 h preformed biofilm by the addition of high phosphate concentration to the medium. These phenotypes were related to the maintenance or re-synthesis of polyP in stationary phase in static conditions. No biofilm formation was observed in ppk?ppx? or ppk?ppx?/ppk+ strains, deficient in polyP synthesis and hydrolysis, respectively. luxS and lsrK mutants, impaired in autoinducer-2 quorum sensing signal metabolism, were unable to form biofilm unless conditioned media from stationary phase wild type cells grown in low phosphate were used. We conclude that polyP degradation is required for biofilm formation in sufficient phosphate media, activating or triggering the production of autoinducer-2. According to our results, phosphate concentration of the culture media should be carefully considered in bacterial adhesion and virulence studies. PMID:23226268

  18. Planktonic and biofilm-grown nitrogen-cycling bacteria exhibit different susceptibilities to copper nanoparticles.

    PubMed

    Reyes, Vincent C; Opot, Stephen O; Mahendra, Shaily

    2015-04-01

    Proper characterization of nanoparticle (NP) interactions with environmentally relevant bacteria under representative conditions is necessary to enable their sustainable manufacture, use, and disposal. Previous nanotoxicology research based on planktonic growth has not adequately explored biofilms, which serve as the predominant mode of bacterial growth in natural and engineered environments. Copper nanoparticle (Cu-NP) impacts on biofilms were compared with respective planktonic cultures of the ammonium-oxidizing Nitrosomonas europaea, nitrogen-fixing Azotobacter vinelandii, and denitrifying Paracoccus denitrificans using a suite of independent toxicity diagnostics. Median inhibitory concentration (IC50) values derived from adenosine triphosphate (ATP) for Cu-NPs were lower in N. europaea biofilms (19.6??15.3?mg/L) than in planktonic cells (49.0??8.0?mg/L). However, in absorbance-based growth assays, compared with unexposed controls, N. europaea growth rates in biofilms were twice as resilient to inhibition than those in planktonic cultures. Similarly, relative to unexposed controls, growth rates and yields of P. denitrificans in biofilms exposed to Cu-NPs were 40-fold to 50-fold less inhibited than those in planktonic cells. Physiological evaluation of ammonium oxidation and nitrate reduction suggested that biofilms were also less inhibited by Cu-NPs than planktonic cells. Furthermore, functional gene expression for ammonium oxidation (amoA) and nitrite reduction (nirK) showed lower inhibition by NPs in biofilms relative to planktonic-grown cells. These results suggest that biofilms mitigate NP impacts, and that nitrogen-cycling bacteria in wastewater, wetlands, and soils might be more resilient to NPs than planktonic-based assessments suggest. PMID:25556815

  19. Identification and characterization of biofilm formation-defective mutants of Xanthomonas citri subsp. citri.

    PubMed

    Malamud, Florencia; Homem, Rafael Augusto; Conforte, Valeria Paola; Yaryura, Pablo Marcelo; Castagnaro, Atilio Pedro; Marano, Mara Rosa; do Amaral, Alexandre Morais; Vojnov, Adrin Alberto

    2013-09-01

    Xanthomonas citri subsp. citri (Xcc) develops a biofilm structure both in vitro and in vivo. Despite all the progress achieved by studies regarding biofilm formation, many of its mechanisms remain poorly understood. This work focuses on the identification of new genes involved in biofilm formation and how they are related to motility, virulence and chemotaxis in Xcc. A Tn5 library of approximately 6000 Xcc (strain 306) mutants was generated and screened to search for biofilm formation defective strains. We identified 23 genes not previously associated with biofilm formation. The analysis of the 23 mutants not only revealed the involvement of new genes in biofilm formation, but also reinforced the importance of exopolysaccharide production, motility and cell surface structures in this process. This collection of biofilm-defective mutants underscores the multifactorial genetic programme underlying the establishment of biofilm in Xcc. PMID:23813675

  20. Insights on Escherichia coli Biofilm Formation and Inhibition from Whole-Transcriptome Profiling

    PubMed Central

    Wood, Thomas K.

    2008-01-01

    SUMMARY Biofilms transform independent cells into specialized cell communities. Here are presented some insights into biofilm formation ascertained with the best-characterized strain, Escherichia coli. Investigations of biofilm formation and inhibition with this strain using whole-transcriptome profiling coupled to phenotypic assays, in vivo DNA binding studies, and isogenic mutants have led to discoveries related to the role of stress, to the role of intra- and interspecies cell signaling, to the impact of the environment on cell signaling, to biofilm inhibition by manipulating cell signaling, to the role of toxin/anti-toxin genes in biofilm formation, and to the role of small RNAs on biofilm formation and dispersal. Hence, E. coli is an excellent resource for determining paradigms in biofilm formation and biofilm inhibition. PMID:19125816

  1. The role of conditioning film formation and surface chemical changes on Xylella fastidiosa adhesion and biofilm evolution.

    PubMed

    Lorite, Gabriela S; Rodrigues, Carolina M; de Souza, Alessandra A; Kranz, Christine; Mizaikoff, Boris; Cotta, Mnica A

    2011-07-01

    Biofilms are complex microbial communities with important biological functions including enhanced resistance against external factors like antimicrobial agents. The formation of a biofilm is known to be strongly dependent on substrate properties including hydrophobicity/hydrophilicity, structure, and roughness. The adsorption of (macro)molecules on the substrate, also known as conditioning film, changes the physicochemical properties of the surface and affects the bacterial adhesion. In this study, we investigate the physicochemical changes caused by Periwinkle wilt (PW) culture medium conditioning film formation on different surfaces (glass and silicon) and their effect on X. fastidiosa biofilm formation. Contact angle measurements have shown that the film formation decreases the surface hydrophilicity degree of both glass and silicon after few hours. Atomic force microscopy (AFM) images show the glass surface roughness is drastically reduced with conditioning film formation. First-layer X. fastidiosa biofilm on glass was observed in the AFM liquid cell after a period of time similar to that determined for the hydrophilicity changes. In addition, attenuation total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy supports the AFM observation, since the PW absorption spectra increases with time showing a stronger contribution from the phosphate groups. Although hydrophobic and rough surfaces are commonly considered to increase bacteria cell attachment, our results suggest that these properties are not as important as the surface functional groups resulting from PW conditioning film formation for X. fastidiosa adhesion and biofilm development. PMID:21486669

  2. The exopolysaccharide PsleDNA interaction enables the formation of a biofilm skeleton in Pseudomonas aeruginosa

    PubMed Central

    Wang, Shiwei; Liu, Xi; Liu, Hongsheng; Zhang, Li; Guo, Yuan; Yu, Shan; Wozniak, Daniel J.; Ma, Luyan Z.

    2015-01-01

    Summary A hallmark of bacterial biofilms is a self-produced extracellular matrix of exopolysaccharide, extracellular DNA (eDNA) and proteins that hold bacterial cells together in the community. However, interactions among matrix components and how the interactions contribute to the formation of matrix remain unclear. Here, we show the physical interaction between exopolysaccharide Psl and eDNA, the two key biofilm matrix components of the opportunistic pathogen Pseudomonas aeruginosa. The interaction allows the two components to combine to form a web of eDNAPsl fibres, which resembles a biofilm skeleton in the centre of pellicles to give bacteria structural support and capability against agents targeted on one matrix component. The web of eDNAPsl fibres was also found in flow-cell biofilms at microcolonies initiation stage. The colocalization of eDNA or Psl fibres with bacterial cell membrane stain suggests that fibre-like eDNA is likely derived from the lysis of dead bacteria in biofilms. Psl can interact with DNA from diverse sources, suggesting that P. aeruginosa has the ability to use DNA of other organisms (such as human neutrophils and other bacterial species) to form its own communities, which might increase the survival of P. aeruginosa in multispecies biofilms or within a human host. PMID:25472701

  3. Effects of pipe materials on chlorine-resistant biofilm formation under long-term high chlorine level.

    PubMed

    Zhu, Zebing; Wu, Chenguang; Zhong, Dan; Yuan, Yixing; Shan, Lili; Zhang, Jie

    2014-07-01

    Drinking water distribution systems are composed of various pipe materials and may harbor biofilms even in the continuous presence of disinfectants. Biofilms formation on five pipe materials (copper (Cu), polyethylene (PE), stainless steel (STS), cast iron (CI), and concrete-coated polycarbonate (CP)) within drinking water containing 1.20mg/L free chlorine, was investigated by flow cytometry, heterotrophic plate counts, and denaturing gradient gel electrophoresis analysis. Results showed that the biofilms formation varied in pipe materials. The biofilm formed on CP initially emerged the highest biomass in 12days, but CI presented the significantly highest biomass after 28days, and Cu showed the lowest bacterial numbers before 120days, while STS expressed the lowest bacterial numbers after 159days. In the biofilm community structure, Moraxella osloensis and Sphingomonas sp. were observed in all the pipe materials while Bacillus sp. was detected except in the CP pipe and Stenotrophomonas maltophila was found from three pipe materials (Cu, PE, and STS). Other bacteria were only found from one or two pipe materials. It is noteworthy that there are 11 opportunistic pathogens in the 17 classified bacterial strains. This research has afforded crucial information regarding the influence of pipe materials on chlorine-resistant biofilm formation. PMID:24828580

  4. Biofilm formation and antibiotic production in Ruegeria mobilis are influenced by intracellular concentrations of cyclic dimeric guanosinmonophosphate.

    PubMed

    D'Alvise, Paul W; Magdenoska, Olivera; Melchiorsen, Jette; Nielsen, Kristian F; Gram, Lone

    2014-05-01

    In many species of the marine Roseobacter clade, periods of attached life, in association with phytoplankton or particles, are interspersed with planktonic phases. The purpose of this study was to determine whether shifts between motile and sessile life in the globally abundant Roseobacter clade species Ruegeria mobilis are associated with intracellular concentrations of the signal compound cyclic dimeric guanosinmonophosphate (c-di-GMP), which in bacteria regulates transitions between motile and sessile life stages. Genes for diguanylate cyclases and phosphodiesterases, which are involved in c-di-GMP signalling, were found in the genome of R.?mobilis strain F1926. Ion pair chromatography-tandem mass spectrometry revealed 20-fold higher c-di-GMP concentrations per cell in biofilm-containing cultures than in planktonic cells. An introduced diguanylate cyclase gene increased c-di-GMP and enhanced biofilm formation and production of the potent antibiotic tropodithietic acid (TDA). An introduced phosphodiesterase gene decreased c-di-GMP and reduced biofilm formation and TDA production. tdaC, a key gene for TDA biosynthesis, was expressed only in attached or biofilm-forming cells, and expression was induced immediately after initial attachment. In conclusion, c-di-GMP signalling controls biofilm formation and biofilm-associated traits in R.?mobilis and, as suggested by presence of GGDEF and EAL domain protein genes, also in other Roseobacter clade species. PMID:24118907

  5. Characterising the flux of carbon between calcium carbonate substrata, aqueous fluids, bacteria and a biofilm matrix

    NASA Astrophysics Data System (ADS)

    Rankin, S. C.; Cooke, D. A.; Handley, P. S.; Merrifield, C. M.; Wogelius, R. A.

    2003-04-01

    Quantification of the flux of elements between minerals, biofilms and aqueous solutions is essential in order to fully elucidate the role of microorganisms in mass transfer processes. Bacteria play a fundamental role in nearly all life and environmental processes and are by far the most abundant organisms on the planet. Their main mode of growth is in the form of biofilms growing on surfaces and although extensive study has been carried out into the problems biofilms cause to humans, the effects of biofilms in the environment are still poorly understood. Much of the published research describing biofilm growth on geological substrata emphasises the species present rather than their effect on the substratum. Although previous studies have shown that the production of organic or mineral acids by microbial biofilms can cause dissolution of mineral substrata, there is little quantitative data on the specific flux of elements between minerals, microbial cells, biofilm matrix and aqueous solutions. With growing evidence that microbial life occurs in abundance in the subsurface, biofilm activity within buried rocks and sediments may have important implications for global geochemical cycling of specific elements. Results will be presented as part of an ongoing laboratory analog experiment which has been designed to quantify the flux of carbon between all matrices in a laboratory substratum-biofilm-aqueous system. Water collected from a limestone cave system (pH 7.5-8; viable count 4.710^3 - 2.010^4 cfu.ml-1{) is used as innoculum and nutrient source for growing mixed consortium biofilms on a natural calcite (CaCO_3) substratum in a flow-through reaction cell (24 days; 25^oC; 1ml.min^{-1). Portions of the biofilm are periodically removed for microbiological analysis and the mineral surface microscopically examined for extent of alteration. A parallel experiment utilises an isotopically labelled synthetic 13C-CaCO_3 substratum. This enables carbon to be traced from the substratum, through the biofilm and into the aqueous and gas phase by analysing 13C/12C isotopic ratios in all system components. Through this mass-balance approach it is possible to quantify, for the first time, the carbon fluxes into the biofilm and the aqueous solution from the carbonate mineral substrate.

  6. Potentials of Mouthwashes in Disinfecting Cariogenic Bacteria and Biofilms Leading to Inhibition of Caries

    PubMed Central

    Oyanagi, Takehiro; Tagami, Junji; Matin, Khairul

    2012-01-01

    Objectives: The aim of this study was to compare the effects of certain commercially available mouthwashes on cariogenic bacteria and biofilms, following the acquisition of inhibition potentials of caries. Materials and Methods: Mouthwashes containing I) chlorhexidine gluconate (CHG; 0.0005% w/v), II) benzethonium chloride (BTC; 0.01% w/v), III) an essential oil (Listerine), and IV) povidone-iodine (PVP-I; 0.035% w/v) were tested on planktonic cariogenic bacteria, biofilms, and an ex vivo caries model. Bacterial aliquots were inoculated with each solution separately and vortexed for 10 seconds at room temperature. Bacterial viability was subsequently investigated by fluorescence microscopy (FM) after staining with a BacLight viability kit and the number of colony-forming units (CFUs) was counted. Similarly, mouthwash solutions were applied to artificial cariogenic biofilms, and bacterial viability of the biofilms was investigated as stated above. Inhibition potentials of two selected mouthwashes of carious lesions were investigated using biofilm-induced caries and a secondary caries model. In all steps, a phosphate-buffered saline (PBS) solution was included as a control. Results: Planktonic cariogenic bacteria and bacteria embedded in biofilms were killed in remarkably large numbers with Listerine and PVP-I treatment compared to PBS and other gargles. CFU counts also showed significant reduction after treatment with Listerine and PVP-I compared to other solutions (P<0.05). Listerine also displayed significant (P<0.05) inhibition effects in preventing the progression of demineralization. Conclusion: Bactericidal potencies of the mouthwashes varied significantly, suggesting that mouthwashes like Listerine can be useful for the prevention of caries and secondary caries. PMID:22303415

  7. Patterns of biofilm formation in intermittent and permanent streams: analysis of biofilm structure and metabolism

    NASA Astrophysics Data System (ADS)

    Artigas, J.; Schwartz, T.; Kirchen, S.; Roman, A. M.; Fund, K.; Obst, U.; Sabater, S.

    2009-04-01

    The development and functioning of benthic microbial communities in streams is largely dependent on the hydrological conditions. Climate change projections predict that the hydrological characteristics will probably be affected because of the rainfall regime. Hence, rivers from the Mediterranean region will become more similar to those draining arid or desert regions, while temperate streams will suffer of higher water flow fluctuations. In this study, we compared the process of biofilm formation between an intermittent (the Fuirosos, Mediterranean) and a permanent (the Walzbach, Central European) stream. Specifically, we analyzed the succession of bacterial and algal populations in the biofilm through bacterial rDNA sequences analysis (16S rDNA and 16S-23S intergenic sequence) and diatom taxa identification over a 60-days colonization experiment. Moreover, changes in biofilm structural (microbial biomass and extracellular polysaccharide content) and metabolic (extracellular enzyme activities) parameters were also analyzed. The successional patterns of microbial populations in the Fuirosos showed clear discontinutities coinciding with flood episodes while at the Walzbach the time sequence was more gradual. Although both study sites were forested, greater microbial biomass standing stock (algal and bacterial) and greater species biodiversity was detected during biofilm development at the Mediterranean site. The higher bacterial biodiversity may be related to the potential effect of flooding episodes in reducing biological interactions in complex microbial communities, such as the competitive exclusion of species. Moreover, the presence of rapid colonizing diatom species might be an adaptation to hydrological changes. In contrast, species competition could define the more stable environments, such as that observed in the Central European stream. Overall, the hystorical evolutionary pressure from the different bioclimatic regions could be also affecting the microbial community composition. Further, the analysis of the whole biofilm colonization sequence showed a greater EPS development and a higher potential extracellular enzyme activity rates in the Mediterranean stream. The higher EPS reflected a functional response of the biofilms to avoid detachment during high flow episodes and the higher enzyme activities were according to the low water nutrient concentration available for microbes. However, the higher nutrient conditions (higher nitrate and phosphate concentrations) at the Central European stream was not reflected on higher biomass standing stock in biofilms. Likely, the biomass accrual of biofilms was related to the differences in climatic conditions between study sites (e. g. daily insulation, temperature oscillation). The results suggest that microbial community development and functioning is primarily related to the physical characteristics of the different sites (specially the stream hydrology, but also the light regime).

  8. Eradication of Bacteria in Suspension and Biofilms Using Methylene Blue-Loaded Dynamic Nanoplatforms?

    PubMed Central

    Wu, Jianfeng; Xu, Hao; Tang, Wei; Kopelman, Raoul; Philbert, Martin A.; Xi, Chuanwu

    2009-01-01

    The bacterial killing efficiency of a dynamic nanoplatform (DNP) was evaluated. The polyacrylamide (PAA) hydrogel matrix of the DNP was loaded with methylene blue (MB) and was previously applied successfully to killing rat C6 glioma tumor cells in culture. This series of experiments is aimed at determining the suitability of this nanoplatform for elimination of bacterial infections. Suspended cultures of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter sp. were exposed to activated (?650-nm laser light) MB-PAA-DNPs. The killing efficiency of nanoparticle mass concentration, light irradiance and fluence, and dark incubation time was determined on each of the bacterial species. Moreover, the ability of activated MB-PAA-DNPs to inhibit biofilm growth and eradicate and disperse preformed biofilms, preformed on glass and polystyrene surfaces, was demonstrated. The data revealed that activated MB-PAA-DNPs eradicated all species of bacteria examined. Also, encapsulation of MB into the PAA-DNP matrix significantly diminished the observed dark toxicity of free dye. The photobactericidal efficacy of MB-PAA-DNP was found to be higher for gram-positive bacteria than for gram-negative bacteria. In addition, activated MB-PAA-DNP can inhibit biofilm growth and eradicate almost all of the early-age biofilms that are formed by all of the bacteria examined. PMID:19414585

  9. Biofilm formation by Staphylococcus aureus isolates from skin and soft tissue infections.

    PubMed

    Kwiecinski, Jakub; Kahlmeter, Gunnar; Jin, Tao

    2015-05-01

    Many diseases caused by Staphylococcus aureus are associated with biofilm formation. However, the ability of S. aureus isolates from skin and soft tissue infections to form biofilms has not yet been investigated. We tested 160 isolates from patients with various skin infections for biofilm-forming capacity in different growth media. All the isolates formed biofilms, the extent of which depended on the type of growth medium. The thickest biofilms were formed when both plasma and glucose were present in the broth; in this case, S. aureus incorporated host fibrin into the biofilm's matrix. There were no differences in the biofilm formation between isolates from different types of skin infections, except for a particularly good biofilm formation by isolates from diabetic wounds and a weaker biofilm formation by isolates from impetigo. In conclusion, biofilm formation is a universal behavior of S. aureus isolates from skin infections. In some cases, such as in diabetic wounds, a particularly strong biofilm formation most likely contributes to the chronic and recurrent character of the infection. Additionally, as S. aureus apparently uses host fibrin as part of the biofilm structure, we suggest that plasma should be included more frequently in in vitro biofilm studies. PMID:25586078

  10. Inhibition of Biofilm Formation by Esomeprazole in Pseudomonas aeruginosa and Staphylococcus aureus

    PubMed Central

    Singh, Vandana; Arora, Vaneet; Alam, M. Jahangir

    2012-01-01

    Staphylococcus aureus and Pseudomonas aeruginosa are common nosocomial pathogens responsible for biofilm-associated infections. Proton pump inhibitors (PPI), such as esomeprazole, may have novel antimicrobial properties. The objective of this study was to assess whether esomeprazole prevents sessile bacterial growth and biofilm formation and whether it may have synergistic killing effects with standard antibiotics. The antibiofilm activity of esomeprazole at 0.25 mM was tested against two strains each of S. aureus and P. aeruginosa. Bacterial biofilms were prepared using a commercially available 96-peg-plate Calgary biofilm device. Sessile bacterial CFU counts and biomass were assessed during 72 hours of esomeprazole exposure. The killing activities after an additional 24 hours of vancomycin (against S. aureus) and meropenem (against P. aeruginosa) treatment with or without preexposure to esomeprazole were also assessed by CFU and biomass analyses. P. aeruginosa and S. aureus strains exposed to esomeprazole displayed decreased sessile bacterial growth and biomass (P < 0.001, each parameter). After 72 h of exposure, there was a 1-log10 decrease in the CFU/ml of esomeprazole-exposed P. aeruginosa and S. aureus strains compared to controls (P < 0.001). After 72 h of exposure, measured absorbance was 100% greater in P. aeruginosa control strains than in esomeprazole-exposed strains (P < 0.001). Increased killing and decreased biomass were observed for esomeprazole-treated bacteria compared to untreated controls exposed to conventional antibiotics (P < 0.001, each parameter). Reduced biofilm growth after 24 h was visibly apparent by light micrographs for P. aeruginosa and S. aureus isolates exposed to esomeprazole compared to untreated controls. In conclusion, esomeprazole demonstrated an antibiofilm effect against biofilm-producing S. aureus and P. aeruginosa. PMID:22664967

  11. In vitro effect of antibiotics on biofilm formation by Bacteroides fragilis group strains isolated from intestinal microbiota of dogs and their antimicrobial susceptibility.

    PubMed

    Silva, Janice Oliveira; Martins Reis, Ana Catarina; Quesada-Gómez, Carlos; Pinheiro, Adriana Queiroz; Freire, Rosemary Souza; Oriá, Reinaldo Barreto; de Carvalho, Cibele Barreto Mano

    2014-08-01

    The Bacteroides fragilis group strains colonize the intestinal tract of dogs as commensal bacteria. Nevertheless, they can be opportunistic pathogens responsible for significant morbidity and mortality rates in dogs, like in oral infections, abscesses and wound infections. The purpose of this study was to evaluate antimicrobial susceptibility in B. fragilis strains isolated from dogs intestinal microbiota and to evaluate the effect of subinhibitory concentrations of some antimicrobials on biofilm formation. A total of 30 B. fragilis group strains were tested for susceptibility to ten antimicrobial agents by broth microdilution method. Thirteen B. fragilis strains were tested for biofilm formation and the biofilm producer strains were chosen to evaluate the effect of subinhibitory concentrations of six antimicrobials on biofilm formation. The isolates were susceptible to amoxicillin-clavulanic acid, metronidazole, imipenem and chloramphenicol. Tetracycline and clindamycin were active against 50% and 33% of the strains, respectively. When biofilm-forming strains were grown in the presence of sub-MICs of imipenem and metronidazole, the inhibition of biofilm formation was observed. In contrast, enrofloxacin at ½ MIC caused a significant increase in biofilm formation in two of four strains examined. In conclusion, the B. fragilis group strains isolated were susceptible to most of the antimicrobials tested and the sub-MIC concentrations of imipenem, metronidazole and clindamycin were able to inhibit the biofilm formation. PMID:24799339

  12. Early microbial biofilm formation on marine plastic debris.

    PubMed

    Lobelle, Delphine; Cunliffe, Michael

    2011-01-01

    An important aspect of the global problem of plastic debris pollution is plastic buoyancy. There is some evidence that buoyancy is influenced by attached biofilms but as yet this is poorly understood. We submerged polyethylene plastic in seawater and sampled weekly for 3 weeks in order to study early stage processes. Microbial biofilms developed rapidly on the plastic and coincided with significant changes in the physicochemical properties of the plastic. Submerged plastic became less hydrophobic and more neutrally buoyant during the experiment. Bacteria readily colonised the plastic but there was no indication that plastic-degrading microorganisms were present. This study contributes to improved understanding of the fate of plastic debris in the marine environment. PMID:21093883

  13. Studies on Biofilm Formation and Interactions of Salmonella enterica with Romaine-Lettuce Leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The association between biofilm formation and the interactions of Salmonella enterica serovars with cut-Romaine-lettuce leaves was investigated. Biofilm formation by 8 S. enterica serovars was tested on polystyrene microtiter plates in the presence of different growth media. Maximal biofilm mass was...

  14. Capillary isoelectric focusing--useful tool for detection of the biofilm formation in Staphylococcus epidermidis.

    PubMed

    Ruzicka, Filip; Horka, Marie; Hola, Veronika; Votava, Miroslav

    2007-03-01

    The biofilm formation is an important factor of S. epidermidis virulence. Biofilm-positive strains might be clinically more important than biofilm-negative ones. Unlike biofilm-negative staphylococci, biofilm-positive staphylococci are surrounded with an extracellular polysaccharide substance. The presence of this substance on the surface can affect physico-chemical properties of the bacterial cell, including surface charge. 73 S. epidermidis strains were examined for the presence of ica operon, for the ability to form biofilm by Christensen test tube method and for the production of slime by Congo red agar method. Isoelectric points (pI) of these strains were determined by means of Capillary Isoelectric Focusing. The biofilm negative strains focused near pI value 2.3, while the pI values of the biofilm positive strains were near 2.6. Isoelectric point is a useful criterion for the differentiation between biofilm-positive and biofilm-negative S. epidermidis strains. PMID:17157942

  15. [Biofilms of the oral cavity. Formation, development and involvement in the onset of diseases related to bacterial plaque increase].

    PubMed

    Bortolaia, C; Sbordone, L

    2002-05-01

    Biofilm is defined as a community of bacteria intimately associated with each other and included within an exopolymer matrix: this biological unit exhibits its own properties, quite different in comparison with those showed by the single species in planktonic form. The oral cavity appears as an open ecosystem, with a dynamic balance between the entrance of microrganisms, colonisation modalities and host defences aimed to their removal: to avoid elimination, bacteria need to adhere to either hard dental surfaces or epithelial surfaces. The oral biofilm formation and development, and the inside selection of specific microrganisms have been correlated with the most common oral pathologies, such as dental caries, periodontal disease and peri-implantitis. Many of these bacteria are usual saprophytes of the oral environment, that, in particular situations, can overcome and express their virulence factors: to better understand the mechanisms of these pathologies it's necessary to know the complex interactions between all the bacterial species inside the biofilm and host tissues and responses. The present paper is a review of the most significant studies on the biofilm development modalities, their correlations with either health or illness of the oral cavity, the bacterial co-aggregation strategies and the biofilm response to antimicrobial agents. PMID:12070469

  16. A prospective study on evaluation of pathogenesis, biofilm formation, antibiotic susceptibility of microbial community in urinary catheter

    NASA Astrophysics Data System (ADS)

    Younis, Khansa Mohammed; Usup, Gires; Ahmad, Asmat

    2015-09-01

    This study is aimed to isolate, detect biofilm formation ability and antibiotic susceptibility of urinary catheter adherent microorganisms from elderly hospitalized patient at the Universiti Kebangsaan Malaysia Medical Center. Microorganisms were isolated from three samples of urinary catheters (UC) surface; one of the acute vascular rejection patient (UCB) and two from benign prostate hyperplasia patients (UCC and UCD). A total of 100 isolates was isolated with 35 from UCB, 38 (UCC) and 28 (UCD). Ninety six were identified as Gram-negative bacilli, one Gram-positive bacilli and three yeasts. Results of biofilm forming on sterile foley catheter showed that all the isolates can form biofilm at different degrees; strong biofilm forming: 32% from the 35 isolates (UCB), 25% out of 38 isolates (UCC), 26% out of 28 isolates (UCD). As for moderate biofilm forming; 3% from UCB, 10% from UCC and 2% from UCD. Weak biofilm forming in UCC (3%). The antibiotic susceptibility for (UCB) isolates showed highly resistant to ampicillin, novobiocin and penicillin 100 (%), kanamycin (97%), tetracycline (94%), chloramphenicol (91%), streptomycin (77%) and showed low level of resistance to gentamycin (17%), while all the isolates from (UCC-D) showed high resistant towards ampicillin and penicillin, novobiocin (94%), tetracycline (61%), streptomycin (53%), gentamycin (50%) and low level of resistance to kanamycin (48%), chloramphenicol (47%). The findings indicate that these isolates can spread within the community on urinary catheters surface and produce strong biofilm, therefore, monitoring antibiotic susceptibility of bacteria isolated in the aggregation is recommended.

  17. Antibiotic-loaded synthetic calcium sulfate beads for prevention of bacterial colonization and biofilm formation in periprosthetic infections.

    PubMed

    Howlin, R P; Brayford, M J; Webb, J S; Cooper, J J; Aiken, S S; Stoodley, P

    2015-01-01

    Periprosthetic infection (PI) causes significant morbidity and mortality after fixation and joint arthroplasty and has been extensively linked to the formation of bacterial biofilms. Poly(methyl methacrylate) (PMMA), as a cement or as beads, is commonly used for antibiotic release to the site of infection but displays variable elution kinetics and also represents a potential nidus for infection, therefore requiring surgical removal once antibiotics have eluted. Absorbable cements have shown improved elution of a wider range of antibiotics and, crucially, complete biodegradation, but limited data exist as to their antimicrobial and antibiofilm efficacy. Synthetic calcium sulfate beads loaded with tobramycin, vancomycin, or vancomycin-tobramycin dual treatment (in a 1:0.24 [wt/wt] ratio) were assessed for their abilities to eradicate planktonic methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis relative to that of PMMA beads. The ability of the calcium sulfate beads to prevent biofilm formation over multiple days and to eradicate preformed biofilms was studied using a combination of viable cell counts, confocal microscopy, and scanning electron microscopy of the bead surface. Biofilm bacteria displayed a greater tolerance to the antibiotics than their planktonic counterparts. Antibiotic-loaded beads were able to kill planktonic cultures of 10(6) CFU/ml, prevent bacterial colonization, and significantly reduce biofilm formation over multiple days. However, established biofilms were harder to eradicate. These data further demonstrate the difficulty in clearing established biofilms; therefore, early preventive measures are key to reducing the risk of PI. Synthetic calcium sulfate loaded with antibiotics has the potential to reduce or eliminate biofilm formation on adjacent periprosthetic tissue and prosthesis material and, thus, to reduce the rates of periprosthetic infection. PMID:25313221

  18. Antibiotic-Loaded Synthetic Calcium Sulfate Beads for Prevention of Bacterial Colonization and Biofilm Formation in Periprosthetic Infections

    PubMed Central

    Howlin, R. P.; Brayford, M. J.; Webb, J. S.; Cooper, J. J.; Aiken, S. S.

    2014-01-01

    Periprosthetic infection (PI) causes significant morbidity and mortality after fixation and joint arthroplasty and has been extensively linked to the formation of bacterial biofilms. Poly(methyl methacrylate) (PMMA), as a cement or as beads, is commonly used for antibiotic release to the site of infection but displays variable elution kinetics and also represents a potential nidus for infection, therefore requiring surgical removal once antibiotics have eluted. Absorbable cements have shown improved elution of a wider range of antibiotics and, crucially, complete biodegradation, but limited data exist as to their antimicrobial and antibiofilm efficacy. Synthetic calcium sulfate beads loaded with tobramycin, vancomycin, or vancomycin-tobramycin dual treatment (in a 1:0.24 [wt/wt] ratio) were assessed for their abilities to eradicate planktonic methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis relative to that of PMMA beads. The ability of the calcium sulfate beads to prevent biofilm formation over multiple days and to eradicate preformed biofilms was studied using a combination of viable cell counts, confocal microscopy, and scanning electron microscopy of the bead surface. Biofilm bacteria displayed a greater tolerance to the antibiotics than their planktonic counterparts. Antibiotic-loaded beads were able to kill planktonic cultures of 106 CFU/ml, prevent bacterial colonization, and significantly reduce biofilm formation over multiple days. However, established biofilms were harder to eradicate. These data further demonstrate the difficulty in clearing established biofilms; therefore, early preventive measures are key to reducing the risk of PI. Synthetic calcium sulfate loaded with antibiotics has the potential to reduce or eliminate biofilm formation on adjacent periprosthetic tissue and prosthesis material and, thus, to reduce the rates of periprosthetic infection. PMID:25313221

  19. Staphylococcal biofilm formation as affected by type acidulant.

    PubMed

    Nostro, Antonia; Cellini, Luigina; Ginestra, Giovanna; D'Arrigo, Manuela; di Giulio, Mara; Marino, Andreana; Blanco, Anna Rita; Favaloro, Angelo; Bisignano, Giuseppe

    2014-07-01

    Staphylococcal growth and biofilm formation in culture medium where pH was lowered with weak organic (acetic and lactic) or strong inorganic (hydrochloric) acids were studied. The effects were evaluated by biomass measurements, cell-surface hydrophobicity, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). The results demonstrated that the inhibition was related to type of acidulant and pH value. At pH 5.0, the antibacterial effect was more pronounced in the presence of acetic acid (58-60% growth reduction) compared with that in the presence of lactic (7-16% growth reduction) and hydrochloric acids (23-24% reduction). The biofilm biomass of Staphylococcus aureus and Staphylococcus epidermidis was reduced by 92, 85, 63, and 93, 87, 81% after exposition to acetic, lactic, and hydrochloric acids, respectively. Increasing the pH from 5.0 to 6.0 resulted in a noticeable reduction in the effectiveness of acids. A minor cells hydrophobic character was also documented. The SEM and CLSM revealed a poorly structured and thinner biofilm compared with the dense and multilayered control. Acidic environment could have important implications for food-processing system to prevent bacterial colonization and control biofilm formation. The findings of this study lead to consider the rational use of the type of acid to achieve acidic environments. PMID:24320800

  20. Polyketide Glycosides from Bionectria ochroleuca Inhibit Candida albicans Biofilm Formation

    PubMed Central

    2015-01-01

    One of the challenges presented by Candida infections is that many of the isolates encountered in the clinic produce biofilms, which can decrease these pathogens susceptibilities to standard-of-care antibiotic therapies. Inhibitors of fungal biofilm formation offer a potential solution to counteracting some of the problems associated with Candida infections. A screening campaign utilizing samples from our fungal extract library revealed that a Bionectria ochroleuca isolate cultured on Cheerios breakfast cereal produced metabolites that blocked the in vitro formation of Candida albicans biofilms. A scale-up culture of the fungus was undertaken using mycobags (also known as mushroom bags or spawn bags), which afforded four known [TMC-151s CF (14)] and three new [bionectriols BD (57)] polyketide glycosides. All seven metabolites exhibited potent biofilm inhibition against C. albicans SC5314, as well as exerted synergistic antifungal activities in combination with amphotericin B. In this report, we describe the structure determination of the new metabolites, as well as compare the secondary metabolome profiles of fungi grown in flasks and mycobags. These studies demonstrate that mycobags offer a useful alternative to flask-based cultures for the preparative production of fungal secondary metabolites. PMID:25302529

  1. Polyketide glycosides from Bionectria ochroleuca inhibit Candida albicans biofilm formation.

    PubMed

    Wang, Bin; You, Jianlan; King, Jarrod B; Cai, Shengxin; Park, Elizabeth; Powell, Douglas R; Cichewicz, Robert H

    2014-10-24

    One of the challenges presented by Candida infections is that many of the isolates encountered in the clinic produce biofilms, which can decrease these pathogens' susceptibilities to standard-of-care antibiotic therapies. Inhibitors of fungal biofilm formation offer a potential solution to counteracting some of the problems associated with Candida infections. A screening campaign utilizing samples from our fungal extract library revealed that a Bionectria ochroleuca isolate cultured on Cheerios breakfast cereal produced metabolites that blocked the in vitro formation of Candida albicans biofilms. A scale-up culture of the fungus was undertaken using mycobags (also known as mushroom bags or spawn bags), which afforded four known [TMC-151s C-F (1-4)] and three new [bionectriols B-D (5-7)] polyketide glycosides. All seven metabolites exhibited potent biofilm inhibition against C. albicans SC5314, as well as exerted synergistic antifungal activities in combination with amphotericin B. In this report, we describe the structure determination of the new metabolites, as well as compare the secondary metabolome profiles of fungi grown in flasks and mycobags. These studies demonstrate that mycobags offer a useful alternative to flask-based cultures for the preparative production of fungal secondary metabolites. PMID:25302529

  2. Characterization of biofilm formation by Borrelia burgdorferi in vitro.

    PubMed

    Sapi, Eva; Bastian, Scott L; Mpoy, Cedric M; Scott, Shernea; Rattelle, Amy; Pabbati, Namrata; Poruri, Akhila; Burugu, Divya; Theophilus, Priyanka A S; Pham, Truc V; Datar, Akshita; Dhaliwal, Navroop K; MacDonald, Alan; Rossi, Michael J; Sinha, Saion K; Luecke, David F

    2012-01-01

    Borrelia burgdorferi, the causative agent of Lyme disease, has long been known to be capable of forming aggregates and colonies. It was recently demonstrated that Borrelia burgdorferi aggregate formation dramatically changes the in vitro response to hostile environments by this pathogen. In this study, we investigated the hypothesis that these aggregates are indeed biofilms, structures whose resistance to unfavorable conditions are well documented. We studied Borrelia burgdorferi for several known hallmark features of biofilm, including structural rearrangements in the aggregates, variations in development on various substrate matrices and secretion of a protective extracellular polymeric substance (EPS) matrix using several modes of microscopic, cell and molecular biology techniques. The atomic force microscopic results provided evidence that multilevel rearrangements take place at different stages of aggregate development, producing a complex, continuously rearranging structure. Our results also demonstrated that Borrelia burgdorferi is capable of developing aggregates on different abiotic and biotic substrates, and is also capable of forming floating aggregates. Analyzing the extracellular substance of the aggregates for potential exopolysaccharides revealed the existence of both sulfated and non-sulfated/carboxylated substrates, predominately composed of an alginate with calcium and extracellular DNA present. In summary, we have found substantial evidence that Borrelia burgdorferi is capable of forming biofilm in vitro. Biofilm formation by Borrelia species might play an important role in their survival in diverse environmental conditions by providing refuge to individual cells. PMID:23110225

  3. Cholate-Stimulated Biofilm Formation by Lactococcus lactis Cells ?

    PubMed Central

    Zaidi, Arsalan Haseeb; Bakkes, Patrick J.; Krom, Bastiaan P.; van der Mei, Henny C.; Driessen, Arnold J. M.

    2011-01-01

    Bile acid resistance by Lactococcus lactis depends on the ABC-type multidrug transporter LmrCD. Upon deletion of the lmrCD genes, cells can reacquire bile acid resistance upon prolonged exposure to cholate, yielding the ?lmrCDr strain. The resistance mechanism in this strain is non-transporter based. Instead, cells show a high tendency to flocculate, suggesting cell surface alterations. Contact angle measurements demonstrate that the ?lmrCDr cells are equipped with an increased cell surface hydrophilicity compared to those of the parental and wild-type strains, while the surface hydrophilicity is reduced in the presence of cholate. ?lmrCDr cells are poor in biofilm formation on a hydrophobic polystyrene surface, but in the presence of subinhibitory concentrations of cholate, biofilm formation is strongly stimulated. Biofilm cells show an enhanced extracellular polymeric substance production and are highly resistant to bile acids. These data suggest that non-transporter-based cholate resistance in L. lactis is due to alterations in the cell surface that stimulate cells to form resistant biofilms. PMID:21335382

  4. ?(B) affects biofilm formation under the dual stress conditions imposed by adding salt and low temperature in Listeria monocytogenes.

    PubMed

    Lee, Jin-Ju; Lee, Gilho; Shin, Ji-Hyun

    2014-10-01

    The food-borne pathogenic bacteria Listeria monocytogenes can form biofilms on various surfaces including food-processing equipment. Biofilms offer survival benefits to the organisms entrapped against environmental insults. Moreover, the ?(B) transcription factor of L. monocytogenes plays an important role in its survival under various stress conditions. In this study, we evaluated whether ?(B) contributes to biofilm formation when L. monocytogenes is grown under various temperatures and media. When the wild-type strain was grown under static biofilm culture below ambient temperature (15C) for 72 h, the difference in viable cell number (in both planktonic and biofilm cells) between the wild-type and ?sigB mutant increased by adding NaCl to BHI broth (9% salt BHI > 6% salt BHI > BHI, w/v), and the specific activity of ?-galactosidase was highly induced in the wild-type strain grown in 6% salt containing BHI broth. Furthermore, we measured surface-adhered biofilm forming ability using the crystal violet staining method. The wild-type strain formed a four times larger biofilm than that of the ?sigB mutant in 6% salt-BHI medium at 15C over a 72 h incubation and also showed the highest level of ?-galactosidase specific activity. However, both the wild-type and ?sigB mutant L. monocytogenes were defective for forming a biofilm in 9% salt-BHI medium at 15C. Our results suggest that ?(B) plays an enhanced role in surface-adhered biofilm formation when L. monocytogenes encounters dual stress conditions, such as 6% NaCl and low temperature. PMID:25269605

  5. High Levels of Genetic Recombination during Nasopharyngeal Carriage and Biofilm Formation in Streptococcus pneumoniae

    PubMed Central

    Marks, Laura R.; Reddinger, Ryan M.; Hakansson, Anders P.

    2012-01-01

    ABSTRACT Transformation of genetic material between bacteria was first observed in the 1920s using Streptococcus pneumoniae as a model organism. Since then, the mechanism of competence induction and transformation has been well characterized, mainly using planktonic bacteria or septic infection models. However, epidemiological evidence suggests that genetic exchange occurs primarily during pneumococcal nasopharyngeal carriage, which we have recently shown is associated with biofilm growth, and is associated with cocolonization with multiple strains. However, no studies to date have comprehensively investigated genetic exchange during cocolonization in vitro and in vivo or the role of the nasopharyngeal environment in these processes. In this study, we show that genetic exchange during dual-strain carriage in vivo is extremely efficient (10?2) and approximately 10,000,000-fold higher than that measured during septic infection (10?9). This high transformation efficiency was associated with environmental conditions exclusive to the nasopharynx, including the lower temperature of the nasopharynx (32 to 34C), limited nutrient availability, and interactions with epithelial cells, which were modeled in a novel biofilm model in vitro that showed similarly high transformation efficiencies. The nasopharyngeal environmental factors, combined, were critical for biofilm formation and induced constitutive upregulation of competence genes and downregulation of capsule that promoted transformation. In addition, we show that dual-strain carriage in vivo and biofilms formed in vitro can be transformed during colonization to increase their pneumococcal fitness and also, importantly, that bacteria with lower colonization ability can be protected by strains with higher colonization efficiency, a process unrelated to genetic exchange. PMID:23015736

  6. Biofilm Formation Enhances Fomite Survival of Streptococcus pneumoniae and Streptococcus pyogenes

    PubMed Central

    Marks, Laura R.; Reddinger, Ryan M.

    2014-01-01

    Both Streptococcus pyogenes and Streptococcus pneumoniae are widely thought to rapidly die outside the human host, losing infectivity following desiccation in the environment. However, to date, all literature investigating the infectivity of desiccated streptococci has used broth-grown, planktonic populations. In this study, we examined the impact of biofilm formation on environmental survival of clinical and laboratory isolates of S. pyogenes and S. pneumoniae as both organisms are thought to colonize the human host as biofilms. Results clearly demonstrate that while planktonic cells that are desiccated rapidly lose viability both on hands and abiotic surfaces, such as plastic, biofilm bacteria remain viable over extended periods of time outside the host and remain infectious in a murine colonization model. To explore the level and extent of streptococcal fomite contamination that children might be exposed to naturally, direct bacteriologic cultures of items in a day care center were conducted, which demonstrated high levels of viable streptococci of both species. These findings raise the possibility that streptococci may survive in the environment and be transferred from person to person via fomites contaminated with oropharyngeal secretions containing biofilm streptococci. PMID:24371220

  7. Enzyme multilayer coatings inhibit Pseudomonas aeruginosa biofilm formation on urinary catheters.

    PubMed

    Ivanova, Kristina; Fernandes, Margarida M; Mendoza, Ernest; Tzanov, Tzanko

    2015-05-01

    Bacteria use a signaling mechanism called quorum sensing (QS) to form complex communities of surface-attached cells known as biofilms. This protective mode of growth allows them to resist antibiotic treatment and originates the majority of hospital-acquired infections. Emerging alternatives to control biofilm-associated infections and multidrug resistance development interfere with bacterial QS pathways, exerting less selective pressure on bacterial population. In this study, biologically stable coatings comprising the QS disrupting enzyme acylase were built on silicone urinary catheters using a layer-by-layer technique. This was achieved by the alternate deposition of negatively charged enzyme and positively charged polyethylenimine. The acylase-coated catheters efficiently quenched the QS in the biosensor strain Chromobacterium violaceum CECT 5999, demonstrated by approximately 50% inhibition of violacein production. These enzyme multilayer coatings significantly reduced the Pseudomonas aeruginosa ATCC 10145 biofilm formation under static and dynamic conditions in an in vitro catheterized bladder model. The quorum quenching enzyme coatings did not affect the viability of the human fibroblasts (BJ-5ta) over 7 days, corresponding to the extended useful life of urinary catheters. Such enzyme-based approach could be an alternative to the conventional antibiotic treatment for prevention of biofilm-associated urinary tract infections. PMID:25582561

  8. A Role for Amyloid in Cell Aggregation and Biofilm Formation

    PubMed Central

    Garcia, Melissa C.; Lee, Janis T.; Ramsook, Caleen B.; Alsteens, David; Dufrêne, Yves F.; Lipke, Peter N.

    2011-01-01

    Cell adhesion molecules in Saccharomyces cerevisiae and Candida albicans contain amyloid-forming sequences that are highly conserved. We have now used site-specific mutagenesis and specific peptide perturbants to explore amyloid-dependent activity in the Candida albicans adhesin Als5p. A V326N substitution in the amyloid-forming region conserved secondary structure and ligand binding, but abrogated formation of amyloid fibrils in soluble Als5p and reduced cell surface thioflavin T fluorescence. When displayed on the cell surface, Als5p with this substitution prevented formation of adhesion nanodomains and formation of large cellular aggregates and model biofilms. In addition, amyloid nanodomains were regulated by exogenous peptides. An amyloid-forming homologous peptide rescued aggregation and biofilm activity of Als5pV326N cells, and V326N substitution peptide inhibited aggregation and biofilm activity in Als5pWT cells. Therefore, specific site mutation, inhibition by anti-amyloid peturbants, and sequence-specificity of pro-amyloid and anti-amyloid peptides showed that amyloid formation is essential for nanodomain formation and activation. PMID:21408122

  9. Photoautotrophic-heterotrophic biofilm communities: a laboratory incubator designed for growing axenic diatoms and bacteria in defined mixed-species biofilms.

    PubMed

    Buhmann, Matthias; Kroth, Peter G; Schleheck, David

    2012-02-01

    Biofilm communities in the euphotic zone of aquatic habitats comprise photoautotrophic microorganisms, such as diatoms, green algae and cyanobacteria, which produce the organic carbon that fuels the life of a heterotrophic contingent of microorganisms, mostly bacteria. Such photoautotrophic-heterotrophic mixed-species biofilms have received little attention in biofilm research due to a lack of suitable pure-culture laboratory model systems. However, they offer important insight into microbial population dynamics and community interactions during a biofilm-developmental process that shapes highly structured, extremely well-adapted microbial landscapes. Here, we report on the development of a sterile incubation chamber for growing and monitoring axenic phototrophic biofilms, i.e. a sterilizable, illuminated, continuous-flow system for a routine work with pure cultures. The system has been designed to simulate the growth conditions in the shallow, littoral zone of aquatic habitats (horizontal surface, submerged in water, illuminated, aerated). Additional features of the concept include automated photometrical monitoring of biofilm density (as biofilm turbidity), analysis via confocal microscopy, direct harvesting of cells, and options to control illumination, flow velocity, and composition of culture fluid. The application of the system was demonstrated in growth experiments using axenic diatom biofilms, or axenic diatom biofilms co-cultivated with different bacterial strains isolated from epilithic biofilms of an oligotrophic freshwater lake. PMID:23757240

  10. The Role of Antimicrobial Peptides in Preventing Multidrug-Resistant Bacterial Infections and Biofilm Formation

    PubMed Central

    Park, Seong-Cheol; Park, Yoonkyung; Hahm, Kyung-Soo

    2011-01-01

    Over the last decade, decreasing effectiveness of conventional antimicrobial-drugs has caused serious problems due to the rapid emergence of multidrug-resistant pathogens. Furthermore, biofilms, which are microbial communities that cause serious chronic infections and dental plaque, form environments that enhance antimicrobial resistance. As a result, there is a continuous search to overcome or control such problems, which has resulted in antimicrobial peptides being considered as an alternative to conventional drugs. Antimicrobial peptides are ancient host defense effector molecules in living organisms. These peptides have been identified in diverse organisms and synthetically developed by using peptidomimic techniques. This review was conducted to demonstrate the mode of action by which antimicrobial peptides combat multidrug-resistant bacteria and prevent biofilm formation and to introduce clinical uses of these compounds for chronic disease, medical devices, and oral health. In addition, combinations of antimicrobial peptides and conventional drugs were considered due to their synergetic effects and low cost for therapeutic treatment. PMID:22016639

  11. Intercellular interactions in early biofilm formation probed with image analysis and laser trapping

    NASA Astrophysics Data System (ADS)

    Gordon, Vernita; Conrad, Jacinta; Gibiansky, Maxsim; Jin, Fan; Haque, Nyrene; Motto, Dominick; Mathewson, Margie; Spalding, Gabe; Parsek, Matthew; Shrout, Joshua; Wong, Gerard

    2010-03-01

    Inter-bacterial interactions are essential to such fundamental phenomena as motility and biofilm development. Many of these interactions are mediated by quorum sensing to coordinate gene expression among groups of cells. Other influences include contact with a common surface and proximity of neighboring cells. All such mechanisms depend strongly on the spatial structure of the system. We investigate the early stages of biofilm formation. These cells show striking cooperative behavior: neighbor proximity and number correlate with the post-division detachment likelihood of daughter cells. To better study the effects of such spatial structure, we develop a platform that uses laser trapping to control bacterial patterning. We place bacteria on a surface with micron-lengthscale precision and reproducibility. This platform allows systematic study of the effects of neighbor number, density, and orientation on intercellular interactions.

  12. Phylogenetic analysis of nitrate- and sulfate-reducing bacteria in a hydrogen-fed biofilm.

    PubMed

    Ontiveros-Valencia, Aura; Ilhan, Zehra Esra; Kang, Dae-Wook; Rittmann, Bruce; Krajmalnik-Brown, Rosa

    2013-07-01

    Using two membrane biofilm reactors in which hydrogen (H?) was the only exogenous electron donor, we studied the microbial community structure of biofilms composed primarily of denitrifying bacteria (DB) and sulfate-reducing bacteria (SRB). In steady-state EDvSS, H? availability was restricted and varied. In steady-state EAvSS, the input nitrate (NO??) concentration was varied relative to a fixed sulfate (SO??) concentration. SRB co-existed with DB, even when SO?? reduction was absent due to restricted H? availability. UniFrac and principal coordinate analysis indicated that H? availability and electron-acceptor loadings framed the microbial community structure, with H? availability having a greater impact. In EDvSS, restricted H? availability favored heterotrophic DB (i.e. Burkholderiales) compared with autotrophic DB (e.g. Hydrogenophilales and Rhodocyclales). In EAvSS, SO?? reduction lowered the relative abundance of some DB (e.g. Hydrogenophilales), and the biofilm was colonized by Desulfovibrionales and Bacteroidales. Reinforcing the impact of H? availability, EAvSS showed a higher microbial diversity and more even distribution among microbial groups than did EDvSS. Thus, the biofilm community in a H?-fed biofilm with DB and SRB became more heterotrophic when the H? availability was constrained, while low NO?? loading allowed more SO?? reduction, causing a shift to more SRB. PMID:23480779

  13. The influence of bacteria on struvite crystal habit and its importance in urinary stone formation

    NASA Astrophysics Data System (ADS)

    Clapham, L.; McLean, R. J. C.; Nickel, J. C.; Downey, J.; Costerton, J. W.

    1990-07-01

    Infection-induced urinary stones form as a result of a urinary tract infection by urease-producing bacteria. These stones are not totally crystalline in nature but rather consist of an agglomeration of bacteria, organic matrix, and crystal of struvite (MgNH 4PO 4 6H 2O). Crystal formation is related to the ability of the bacteria to effect an increase in the urine pH. Another equally important bacterial role lies in their formation of a 'biofilm' which later becomes the organic matrix constituent of the stone. Results of the present in vitro study indicate that crystals are formed more readily if produced within the bacterial biofilm than in the surrounding urine. It is proposed that supersaturation, due in part to a bacterial-induced pH increase and in part to the metal binding tendency of the biofilm, leads to crystal formation via a gel growth mechanism within the biofilm itself. In time further bacterial cell division, microcolony.

  14. Biofilm formation by Bacillus subtilis: new insights into regulatory strategies and assembly mechanisms

    PubMed Central

    Cairns, Lynne S; Hobley, Laura; Stanley-Wall, Nicola R

    2014-01-01

    Biofilm formation is a social behaviour that generates favourable conditions for sustained survival in the natural environment. For the Gram-positive bacterium Bacillus subtilis the process involves the differentiation of cell fate within an isogenic population and the production of communal goods that form the biofilm matrix. Here we review recent progress in understanding the regulatory pathways that control biofilm formation and highlight developments in understanding the composition, function and structure of the biofilm matrix. PMID:24988880

  15. Analyses of spatial distributions of sulfate-reducing bacteria and their activity in aerobic wastewater biofilms

    SciTech Connect

    Okabe, Satoshi; Itoh, Tsukasa; Satoh, Hisashi; Watanabe, Yoshimasa

    1999-11-01

    The vertical distribution of sulfate-reducing bacteria (SRB) in aerobic wastewater biofilms grown on rotating disk reactors was investigated by fluorescent in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes. To correlate the vertical distribution of SRB populations with their activity, the microprofiles of O{sub 2}, H{sub 2}S, NO{sub 2}{minus}, NH{sub 2}{sup +}, and pH were measured with microelectrodes. In addition, a cross-evaluation of the FISH and microelectrode analyses was performed by comparing them with culture-based approaches and biogeochemical measurements. In situ hybridization revealed that a relatively high abundance of the probe SRB385-stained cells were evenly distributed throughout the biofilm, even in the toxic surface. The probe SRB660-stained Desulfobulbus spp. were found to be numerically important members of SRB populations. The result of microelectrode measurements showed that a high sulfate-reducing activity was found in a narrow anaerobic zone located about 150 to 300 {micro}m below the biofilm surface and above which an intensive sulfide oxidation zone was found. The biogeochemical measurements showed that elemental sulfur (S{degree}) was an important intermediate of the sulfide reoxidation in such thin wastewater biofilms, which accounted for about 75% of the total S pool in the biofilm. The contribution of an internal Fe-sulfur cycle to the overall sulfur cycle in aerobic wastewater biofilms was insignificant (less than 1%) due to the relatively high sulfate reduction rate.

  16. Growth Condition-Dependent Esp Expression by Enterococcus faecium Affects Initial Adherence and Biofilm Formation?

    PubMed Central

    Van Wamel, Willem J. B.; Hendrickx, Antoni P. A.; Bonten, Marc J. M.; Top, Janetta; Posthuma, George; Willems, Rob J. L.

    2007-01-01

    A genetic subpopulation of Enterococcus faecium, called clonal complex 17 (CC-17), is strongly associated with hospital outbreaks and invasive infections. Most CC-17 strains contain a putative pathogenicity island encoding the E. faecium variant of enterococcal surface protein (Esp). Western blotting, flow cytometric analyses, and electron microscopy showed that Esp is expressed and exposed on the surface of E. faecium, though Esp expression and surface exposure are highly varied among different strains. Furthermore, Esp expression depends on growth conditions like temperature and anaerobioses. When grown at 37C, five of six esp-positive E. faecium strains showed significantly increased levels of surface-exposed Esp compared to bacteria grown at 21C, which was confirmed at the transcriptional level by real-time PCR. In addition, a significant increase in surface-exposed Esp was found in half of these strains when grown at 37C under anaerobic conditions compared to the level in bacteria grown under aerobic conditions. Finally, amounts of surface-exposed Esp correlated with initial adherence to polystyrene (R2 = 0.7146) and biofilm formation (R2 = 0.7535). Polystyrene adherence was competitively inhibited by soluble recombinant N-terminal Esp. This study demonstrates that Esp expression on the surface of E. faecium (i) varies consistently between strains, (ii) is growth condition dependent, and (iii) is quantitatively correlated with initial adherence and biofilm formation. These data indicate that E. faecium senses and responds to changing environmental conditions, which might play a role in the early stages of infection when bacteria transit from oxygen-rich conditions at room temperature to anaerobic conditions at body temperature. In addition, variation of surface exposure may explain the contrasting findings reported on the role of Esp in biofilm formation. PMID:17118984

  17. Nitric Oxide Mediates Biofilm Formation and Symbiosis in Silicibacter sp. Strain TrichCH4B

    PubMed Central

    Rao, Minxi; Smith, Brian C.

    2015-01-01

    ABSTRACT Nitric oxide (NO) plays an important signaling role in all domains of life. Many bacteria contain a heme-nitric oxide/oxygen binding (H-NOX) protein that selectively binds NO. These H-NOX proteins often act as sensors that regulate histidine kinase (HK) activity, forming part of a bacterial two-component signaling system that also involves one or more response regulators. In several organisms, NO binding to the H-NOX protein governs bacterial biofilm formation; however, the source of NO exposure for these bacteria is unknown. In mammals, NO is generated by the enzyme nitric oxide synthase (NOS) and signals through binding the H-NOX domain of soluble guanylate cyclase. Recently, several bacterial NOS proteins have also been reported, but the corresponding bacteria do not also encode an H-NOX protein. Here, we report the first characterization of a bacterium that encodes both a NOS and H-NOX, thus resembling the mammalian system capable of both synthesizing and sensing NO. We characterized the NO signaling pathway of the marine alphaproteobacterium Silicibacter sp. strain TrichCH4B, determining that the NOS is activated by an algal symbiont, Trichodesmium erythraeum. NO signaling through a histidine kinase-response regulator two-component signaling pathway results in increased concentrations of cyclic diguanosine monophosphate, a key bacterial second messenger molecule that controls cellular adhesion and biofilm formation. Silicibacter sp. TrichCH4B biofilm formation, activated by T. erythraeum, may be an important mechanism for symbiosis between the two organisms, revealing that NO plays a previously unknown key role in bacterial communication and symbiosis. PMID:25944856

  18. Staphylococcus aureus and MRSA Growth and Biofilm Formation after Treatment with Antibiotics and SeNPs.

    PubMed

    Cihalova, Kristyna; Chudobova, Dagmar; Michalek, Petr; Moulick, Amitava; Guran, Roman; Kopel, Pavel; Adam, Vojtech; Kizek, Rene

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a dangerous pathogen resistant to ?-lactam antibiotics. Due to its resistance, it is difficult to manage the infections caused by this strain. We examined this issue in terms of observation of the growth properties and ability to form biofilms in sensitive S. aureus and MRSA after the application of antibiotics (ATBs)-ampicillin, oxacillin and penicillin-and complexes of selenium nanoparticles (SeNPs) with these ATBs. The results suggest the strong inhibition effect of SeNPs in complexes with conventional ATBs. Using the impedance method, a higher disruption of biofilms was observed after the application of ATB complexes with SeNPs compared to the group exposed to ATBs without SeNPs. The biofilm formation was intensely inhibited (up to 99%7% for S. aureus and up to 94%4% for MRSA) after application of SeNPs in comparison with bacteria without antibacterial compounds whereas ATBs without SeNPs inhibited S. aureus up to 79%5% and MRSA up to 16%2% only. The obtained results provide a basis for the use of SeNPs as a tool for the treatment of bacterial infections, which can be complicated because of increasing resistance of bacteria to conventional ATB drugs. PMID:26501270

  19. Staphylococcus aureus and MRSA Growth and Biofilm Formation after Treatment with Antibiotics and SeNPs

    PubMed Central

    Cihalova, Kristyna; Chudobova, Dagmar; Michalek, Petr; Moulick, Amitava; Guran, Roman; Kopel, Pavel; Adam, Vojtech; Kizek, Rene

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a dangerous pathogen resistant to β-lactam antibiotics. Due to its resistance, it is difficult to manage the infections caused by this strain. We examined this issue in terms of observation of the growth properties and ability to form biofilms in sensitive S. aureus and MRSA after the application of antibiotics (ATBs)—ampicillin, oxacillin and penicillin—and complexes of selenium nanoparticles (SeNPs) with these ATBs. The results suggest the strong inhibition effect of SeNPs in complexes with conventional ATBs. Using the impedance method, a higher disruption of biofilms was observed after the application of ATB complexes with SeNPs compared to the group exposed to ATBs without SeNPs. The biofilm formation was intensely inhibited (up to 99% ± 7% for S. aureus and up to 94% ± 4% for MRSA) after application of SeNPs in comparison with bacteria without antibacterial compounds whereas ATBs without SeNPs inhibited S. aureus up to 79% ± 5% and MRSA up to 16% ± 2% only. The obtained results provide a basis for the use of SeNPs as a tool for the treatment of bacterial infections, which can be complicated because of increasing resistance of bacteria to conventional ATB drugs. PMID:26501270

  20. Characterization of Type 2 Quorum Sensing in Klebsiella pneumoniae and Relationship with Biofilm Formation

    PubMed Central

    Balestrino, Damien; Haagensen, Janus A. J.; Rich, Chantal; Forestier, Christiane

    2005-01-01

    Quorum sensing is a process by which bacteria communicate by using secreted chemical signaling molecules called autoinducers. Many bacterial species modulate the expression of a wide variety of physiological functions in response to changes in population density by this mechanism. In this study, the opportunistic pathogen Klebsiella pneumoniae was observed to secrete type 2 signaling molecules. A homologue of luxS, the gene required for AI-2 synthesis in Vibrio harveyi, was isolated from the K. pneumoniae genome. A V. harveyi bioassay showed the luxS functionality in K. pneumoniae and its ability to complement the luxS-negative phenotype of Escherichia coli DH5?. Autoinducer activity was detected in the supernatant, and maximum expression of specific messengers detected by quantitative reverse transcription-PCR analysis occurred during the late exponential phase. The highest levels of AI-2 were observed in minimal medium supplemented with glycerol. To determine the potential role of luxS in colonization processes, a K. pneumoniae luxS isogenic mutant was constructed and tested for its capacity to form biofilms in vitro on an abiotic surface and to colonize the intestinal tract in a murine model. No difference was observed in the level of intestinal colonization between the wild-type strain and the luxS mutant. Microscopic analysis of biofilm structures revealed that the luxS mutant was able to form a mature biofilm but with reduced capacities in the development of microcolonies, mostly in the early steps of biofilm formation. These data suggest that a LuxS-dependent signal plays a role in the early stages of biofilm formation by K. pneumoniae. PMID:15805533

  1. Vibriophages Differentially Influence Biofilm Formation by Vibrio anguillarum Strains

    PubMed Central

    Tan, Demeng; Dahl, Amalie

    2015-01-01

    Vibrio anguillarum is an important pathogen in marine aquaculture, responsible for vibriosis. Bacteriophages can potentially be used to control bacterial pathogens; however, successful application of phages requires a detailed understanding of phage-host interactions under both free-living and surface-associated growth conditions. In this study, we explored in vitro phage-host interactions in two different strains of V. anguillarum (BA35 and PF430-3) during growth in microcolonies, biofilms, and free-living cells. Two vibriophages, ΦH20 (Siphoviridae) and KVP40 (Myoviridae), had completely different effects on the biofilm development. Addition of phage ΦH20 to strain BA35 showed efficient control of biofilm formation and density of free-living cells. The interactions between BA35 and ΦH20 were thus characterized by a strong phage control of the phage-sensitive population and subsequent selection for phage-resistant mutants. Addition of phage KVP40 to strain PF430-3 resulted in increased biofilm development, especially during the early stage. Subsequent experiments in liquid cultures showed that addition of phage KVP40 stimulated the aggregation of host cells, which protected the cells against phage infection. By the formation of biofilms, strain PF430-3 created spatial refuges that protected the host from phage infection and allowed coexistence between phage-sensitive cells and lytic phage KVP40. Together, the results demonstrate highly variable phage protection mechanisms in two closely related V. anguillarum strains, thus emphasizing the challenges of using phages to control vibriosis in aquaculture and adding to the complex roles of phages as drivers of prokaryotic diversity and population dynamics. PMID:25911474

  2. High-throughput screening of multispecies biofilm formation and quantitative PCR-based assessment of individual species proportions, useful for exploring interspecific bacterial interactions.

    PubMed

    Ren, Dawei; Madsen, Jonas Stenløkke; de la Cruz-Perera, Claudia I; Bergmark, Lasse; Sørensen, Søren J; Burmølle, Mette

    2014-07-01

    Multispecies biofilms are predominant in almost all natural environments, where myriads of resident microorganisms interact with each other in both synergistic and antagonistic manners. The interspecies interactions among different bacteria are, despite the ubiquity of these communities, still poorly understood. Here, we report a rapid, reproducible and sensitive approach for quantitative screening of biofilm formation by bacteria when cultivated as mono- and multispecies biofilms, based on the Nunc-TSP lid system and crystal violet staining. The relative proportion of the individual species in a four-species biofilm was assessed using quantitative PCR based on SYBR Green I fluorescence with specific primers. The results indicated strong synergistic interactions in a four-species biofilm model community with a more than 3-fold increase in biofilm formation and demonstrated the strong dominance of two strains, Xanthomonas retroflexus and Paenibacillus amylolyticus. The developed approach can be used as a standard procedure for evaluating interspecies interactions in defined microbial communities. This will be of significant value in the quantitative study of the microbial composition of multispecies biofilms both in natural environments and infectious diseases to increase our understanding of the mechanisms that underlie cooperation, competition and fitness of individual species in mixed-species biofilms. PMID:24337804

  3. From Nanowires to Biofilms: An Exploration of Novel Mechanisms of Uranium Transformation Mediated by Geobacter Bacteria

    SciTech Connect

    REGUERA, GEMMA

    2014-01-16

    One promising strategy for the in situ bioremediation of radioactive groundwater contaminants that has been identified by the SBR Program is to stimulate the activity of dissimilatory metal-reducing microorganisms to reductively precipitate uranium and other soluble toxic metals. The reduction of U(VI) and other soluble contaminants by Geobacteraceae is directly dependent on the reduction of Fe(III) oxides, their natural electron acceptor, a process that requires the expression of Geobacter’s conductive pili (pilus nanowires). Expression of conductive pili by Geobacter cells leads to biofilm development on surfaces and to the formation of suspended biogranules, which may be physiological closer to biofilms than to planktonic cells. Biofilm development is often assumed in the subsurface, particularly at the matrix-well screen interface, but evidence of biofilms in the bulk aquifer matrix is scarce. Our preliminary results suggest, however, that biofilms develop in the subsurface and contribute to uranium transformations via sorption and reductive mechanisms. In this project we elucidated the mechanism(s) for uranium immobilization mediated by Geobacter biofilms and identified molecular markers to investigate if biofilm development is happening in the contaminated subsurface. The results provided novel insights needed in order to understand the metabolic potential and physiology of microorganisms with a known role in contaminant transformation in situ, thus having a significant positive impact in the SBR Program and providing novel concept to monitor, model, and predict biological behavior during in situ treatments.

  4. Pili in Gram-positive bacteria: assembly, involvement in colonization and biofilm development

    PubMed Central

    Mandlik, Anjali; Swierczynski, Arlene; Das, Asis; Ton-That, Hung

    2010-01-01

    Various cell-surface multisubunit protein polymers, known as pili or fimbriae, have a pivotal role in the colonization of specific host tissues by many pathogenic bacteria. In contrast to Gram-negative bacteria, Gram-positive bacteria assemble pili by a distinct mechanism involving a transpeptidase called sortase. Sortase crosslinks individual pilin monomers and ultimately joins the resulting covalent polymer to the cell-wall peptidoglycan. Here we review current knowledge of this mechanism and the roles of Gram-positive pili in the colonization of specific host tissues, modulation of host immune responses and the development of bacterial biofilms. PMID:18083568

  5. Pili in Gram-positive bacteria: assembly, involvement in colonization and biofilm development.

    PubMed

    Mandlik, Anjali; Swierczynski, Arlene; Das, Asis; Ton-That, Hung

    2008-01-01

    Various cell-surface multisubunit protein polymers, known as pili or fimbriae, have a pivotal role in the colonization of specific host tissues by many pathogenic bacteria. In contrast to Gram-negative bacteria, Gram-positive bacteria assemble pili by a distinct mechanism involving a transpeptidase called sortase. Sortase crosslinks individual pilin monomers and ultimately joins the resulting covalent polymer to the cell-wall peptidoglycan. Here we review current knowledge of this mechanism and the roles of Gram-positive pili in the colonization of specific host tissues, modulation of host immune responses and the development of bacterial biofilms. PMID:18083568

  6. Biofilm in endodontics: A review.

    PubMed

    Jhajharia, Kapil; Parolia, Abhishek; Shetty, K Vikram; Mehta, Lata Kiran

    2015-01-01

    Endodontic disease is a biofilm-mediated infection, and primary aim in the management of endodontic disease is the elimination of bacterial biofilm from the root canal system. The most common endodontic infection is caused by the surface-associated growth of microorganisms. It is important to apply the biofilm concept to endodontic microbiology to understand the pathogenic potential of the root canal microbiota as well as to form the basis for new approaches for disinfection. It is foremost to understand how the biofilm formed by root canal bacteria resists endodontic treatment measures. Bacterial etiology has been confirmed for common oral diseases such as caries and periodontal and endodontic infections. Bacteria causing these diseases are organized in biofilm structures, which are complex microbial communities composed of a great variety of bacteria with different ecological requirements and pathogenic potential. The biofilm community not only gives bacteria effective protection against the host's defense system but also makes them more resistant to a variety of disinfecting agents used as oral hygiene products or in the treatment of infections. Successful treatment of these diseases depends on biofilm removal as well as effective killing of biofilm bacteria. So, the fundamental to maintain oral health and prevent dental caries, gingivitis, and periodontitis is to control the oral biofilms. From these aspects, the formation of biofilms carries particular clinical significance because not only host defense mechanisms but also therapeutic efforts including chemical and mechanical antimicrobial treatment measures have the most difficult task of dealing with organisms that are gathered in a biofilm. The aim of this article was to review the mechanisms of biofilms' formation, their roles in pulpal and periapical pathosis, the different types of biofilms, the factors influencing biofilm formation, the mechanisms of their antimicrobial resistance, techniques to identify biofilms. PMID:25767760

  7. Muramidases found in the foregut microbiome of the Tammar wallaby can direct cell aggregation and biofilm formation

    PubMed Central

    Pope, Phillip B; Totsika, Makrina; Aguirre de Carcer, Daniel; Schembri, Mark A; Morrison, Mark

    2011-01-01

    We describe here the role of muramidases present in clones of metagenomic DNA that result in cell aggregation and biofilm formation by Escherichia coli. The metagenomic clones were obtained from uncultured Lachnospiraceae-affiliated bacteria resident in the foregut microbiome of the Tammar wallaby. One of these fosmid clones (p49C2) was chosen for more detailed studies and a variety of genetic methods were used to delimit the region responsible for the phenotype to an open reading frame of 1425 bp. Comparative sequence analysis with other fosmid clones giving rise to the same phenotype revealed the presence of muramidase homologues with the same modular composition. Phylogenetic analysis of the fosmid sequence data assigned these fosmid inserts to recently identified, but uncultured, phylogroups of Lachnospiraceae believed to be numerically dominant in the foregut microbiome of the Tammar wallaby. The muramidase is a modular protein containing putative N-acetylmuramoyl--alanine amidase and an endo-β-N-acetylglucosaminidase catalytic module, with a similar organization and functional properties to some Staphylococcal autolysins that also confer adhesive properties and biofilm formation. We also show here that the cloned muramidases result in the production of extracellular DNA, which appears to be the key for biofilm formation and autoaggregation. Collectively, these findings suggest that biofilm formation and cell aggregation in gut microbiomes might occur via the concerted action of carbohydrate-active enzymes and the production of extracellular DNA to serve as a biofilm scaffold. PMID:20668486

  8. Biofilm comprising phototrophic, diazotrophic, and hydrocarbon-utilizing bacteria: a promising consortium in the bioremediation of aquatic hydrocarbon pollutants.

    PubMed

    Al-Bader, Dhia; Kansour, Mayada K; Rayan, Rehab; Radwan, Samir S

    2013-05-01

    Biofilms harboring simultaneously anoxygenic and oxygenic phototrophic bacteria, diazotrophic bacteria, and hydrocarbon-utilizing bacteria were established on glass slides suspended in pristine and oily seawater. Via denaturing gradient gel electrophoresis analysis on PCR-amplified rRNA gene sequence fragments from the extracted DNA from biofilms, followed by band amplification, biofilm composition was determined. The biofilms contained anoxygenic phototrophs belonging to alphaproteobacteria; pico- and filamentous cyanobacteria (oxygenic phototrophs); two species of the diazotroph Azospirillum; and two hydrocarbon-utilizing gammaproteobacterial genera, Cycloclasticus and Oleibacter. The coexistence of all these microbial taxa with different physiologies in the biofilm makes the whole community nutritionally self-sufficient and adequately aerated, a condition quite suitable for the microbial biodegradation of aquatic pollutant hydrocarbons. PMID:23089957

  9. Discovering Biofilms: Inquiry-Based Activities for the Classroom

    ERIC Educational Resources Information Center

    Redelman, Carly V.; Marrs, Kathleen; Anderson, Gregory G.

    2012-01-01

    In nature, bacteria exist in and adapt to different environments by forming microbial communities called "biofilms." We propose simple, inquiry-based laboratory exercises utilizing a biofilm formation assay, which allows controlled biofilm growth. Students will be able to qualitatively assess biofilm growth via staining. Recently, we developed a

  10. Discovering Biofilms: Inquiry-Based Activities for the Classroom

    ERIC Educational Resources Information Center

    Redelman, Carly V.; Marrs, Kathleen; Anderson, Gregory G.

    2012-01-01

    In nature, bacteria exist in and adapt to different environments by forming microbial communities called "biofilms." We propose simple, inquiry-based laboratory exercises utilizing a biofilm formation assay, which allows controlled biofilm growth. Students will be able to qualitatively assess biofilm growth via staining. Recently, we developed a…

  11. Rapid redox signal transmission by "Cable Bacteria" beneath a photosynthetic biofilm.

    PubMed

    Malkin, S Y; Meysman, F J R

    2015-02-01

    Recently, long filamentous bacteria, belonging to the family Desulfobulbaceae, were shown to induce electrical currents over long distances in the surface layer of marine sediments. These "cable bacteria" are capable of harvesting electrons from free sulfide in deeper sediment horizons and transferring these electrons along their longitudinal axes to oxygen present near the sediment-water interface. In the present work, we investigated the relationship between cable bacteria and a photosynthetic algal biofilm. In a first experiment, we investigated sediment that hosted both cable bacteria and a photosynthetic biofilm and tested the effect of an imposed diel light-dark cycle by continuously monitoring sulfide at depth. Changes in photosynthesis at the sediment surface had an immediate and repeatable effect on sulfide concentrations at depth, indicating that cable bacteria can rapidly transmit a geochemical effect to centimeters of depth in response to changing conditions at the sediment surface. We also observed a secondary response of the free sulfide at depth manifest on the time scale of hours, suggesting that cable bacteria adjust to a moving oxygen front with a regulatory or a behavioral response, such as motility. Finally, we show that on the time scale of days, the presence of an oxygenic biofilm results in a deeper and more acidic suboxic zone, indicating that a greater oxygen supply can enable cable bacteria to harvest a greater quantity of electrons from marine sediments. Rapid acclimation strategies and highly efficient electron harvesting are likely key advantages of cable bacteria, enabling their success in high sulfide generating coastal sediments. PMID:25416774

  12. Control of marine biofouling and medical biofilm formation with engineered topography

    NASA Astrophysics Data System (ADS)

    Schumacher, James Frederick

    Biofouling is the unwanted accumulation and growth of cells and organisms on clean surfaces. This process occurs readily on unprotected surfaces in both the marine and physiological environments. Surface protection in both systems has typically relied upon toxic materials and biocides. Metallic paints, based on tin and copper, have been extremely successful as antifouling coatings for the hulls of ships by killing the majority of fouling species. Similarly, antibacterial medical coatings incorporate metal-containing compounds such as silver or antibiotics that kill the bacteria. The environmental concerns over the use of toxic paints and biocides in the ocean, the developed antibiotic resistance of bacterial biofilms, and the toxicity concerns with silver suggest the need for non-toxic and non-kill solutions for these systems. The manipulation of surface topography on non-toxic materials at the size scale of the fouling species or bacteria is one approach for the development of alternative coatings. These surfaces would function simply as a physical deterrent of settlement of fouling organisms or a physical obstacle for the adequate formation of a bacterial biofilm without the need to kill the targeted microorganisms. Species-specific topographical designs called engineered topographies have been designed, fabricated and evaluated for potential applications as antifouling marine coatings and material surfaces capable of reducing biofilm formation. Engineered topographies fabricated on the surface of a non-toxic, polydimethylsiloxane elastomer, or silicone, were shown to significantly reduce the attachment of zoospores of a common ship fouling green algae (Ulva) in standard bioassays versus a smooth substrate. Other engineered topographies were effective at significantly deterring the settlement of the cyprids of barnacles (Balanus amphitrite). These results indicate the potential use of engineered topography applied to non-toxic materials as an environmentally friendly coating for antifouling applications in the ocean. In addition, a biomaterial-grade silicone modified with a tailored engineered topography significantly inhibited the bacterial biofilm growth from Staphylococcus aureus for up to 14 days exposure without the use of bactericidal agents. Mature biofilms were present on equivalently exposed smooth silicone surfaces. Engineered surface topographies present a promising means of blocking biofilm development on medical surfaces and reducing the rate of related infections.

  13. Physicochemical changes of microbe and solid surface properties during biofilm formation

    NASA Astrophysics Data System (ADS)

    Sfaelou, Stavroula; Vakros, John; Manariotis, Ioannis D.; Karapanagioti, Hrissi K.

    2013-04-01

    Cell immobilization is a promising biotechnology process. For example, entrapment of bacteria cells on synthetic polymeric matrices such as biocarriers is widely used for wastewater treatment because they have strong mechanical strength and durability in contrast to natural polymers. This method is based on the formation of biofilm on the surface of the used carriers and combines two different processes; attached and suspended biomass in a hybrid system. Previous studies have shown that immobilized cell systems have the potential to degrade toxic chemicals faster than conventional wastewater treatment systems because high densities of specialized microorganisms are used in immobilized cell systems. The present study elucidates the surface charge and properties of activated sludge and their role in the formation of biofilm. This information can be used for the optimization of the formation of biofilms as well as for the study of the transport of microorganisms in different environments. The two types of biocarriers that were used in this study are polyvinyl alcohol (PVA)-gel beads and Moving Bed Biofilm Reactor (MBBR) carriers. The sludge samples that were investigated were taken from the aeration tank of the wastewater treatment plant of University of Patras (Greece). Measurements of the surface charge of the sludge, the biocarriers and the formed biofilm, were performed using potentiometric mass titrations with different kinds of electrolytes (e.g. NaCl, NaNO3) and at pH ranging from 3 to 11. The determination of pzc and surface charge of activated sludge and biocarriers is significant, because it can provide new valuable informations about the interaction mechanisms and the formation of biofilms. In each case, the point of zero charge (pzc) was identified as the common intersection point of the potentiometric curve of the blank solution of the electrolyte with the corresponding curves of each material. The pzc value for the biofilm was 6.1 to 6.7 and 6.6 to 6.9 for PVA gel and MBBR, respectively. These values differ both from the pzc values found for PVA biocarriers (pzc = 9.4; no pzc value was obtained for MBBR as expected based on its hydrophobic nature and the absence of surface groups with acid-base behavior) and the pzc value of activated sludge (activated sludge mixed liquor: pzc = 8.0 to 8.2, solid activated sludge: pzc = 7.2 to 7.3). These results lead us to the conclusion that the formed biofilms have different acid-base behavior and properties in relation to the activated sludge and the biocarriers. This fact is in accordance to previous studies, where biofilm-associated cells can be differentiated from their suspended counterparts due to the generation of an extracellular polymeric substance (EPS) matrix. One other possible explanation is that the complicated processes of the biofilm formation can alter the distribution of different cells in the sludge compared with the cell distribution in the suspended unsupported sludge.

  14. GlpC gene is responsible for biofilm formation and defense against phagocytes and imparts tolerance to pH and organic solvents in Proteus vulgaris.

    PubMed

    Wu, Y L; Liu, K S; Yin, X T; Fei, R M

    2015-01-01

    Biofilm-forming bacteria are highly resistant to antibiotics, host immune defenses, and other external conditions. The formation of biofilms plays a key role in colonization and infection. To explore the mechanism of biofilm formation, mutant strains of Proteus vulgaris XC 2 were generated by Tn5 random transposon insertion. Only one biofilm defective bacterial species was identified from among 500 mutants. Inactivation of the glpC gene coding an anaerobic glycerol-3-phosphate dehydrogenase subunit C was identified by sequence analysis of the biofilm defective strain. Differences were detected in the growth phenotypes of the wild-type and mutant strains under pH, antibiotic, and organic solvent stress conditions. Furthermore, we observed an increase in the phagocytosis of the biofilm defective strain by the mouse macrophage RAW264.7 cell line compared to the wild-type strain. This study shows that the glpC gene plays an important role in biofilm formation, in addition to imparting pH, organic solvent, and antibiotic tolerance, and defense against phagocytosis to Proteus sp. The results further clarified the mechanism of biofilm formation at the genomic level, and indicated the importance of the glpC gene in this process. This data may provide innovative therapeutic measures against P. vulgaris infections; furthermore, as an important crocodile pathogen, this study also has important significance in the protection of Chinese alligators. PMID:26400293

  15. Evaluation of Intraspecies Interactions in Biofilm Formation by Methylobacterium Species Isolated from Pink-Pigmented Household Biofilms

    PubMed Central

    Xu, Fang-Fang; Morohoshi, Tomohiro; Wang, Wen-Zhao; Yamaguchi, Yuka; Liang, Yan; Ikeda, Tsukasa

    2014-01-01

    Concern regarding household biofilms has grown due to their widespread existence and potential to threaten human health by serving as pathogen reservoirs. Previous studies identified Methylobacterium as one of the dominant genera found in household biofilms. In the present study, we examined the mechanisms underlying biofilm formation by using the bacterial consortium found in household pink slime. A clone library analysis revealed that Methylobacterium was the predominant genus in household pink slime. In addition, 16 out of 21 pink-pigmented bacterial isolates were assigned to the genus Methylobacterium. Although all of the Methylobacterium isolates formed low-level biofilms, the amount of the biofilms formed by Methylobacterium sp. P-1M and P-18S was significantly increased by co-culturing with other Methylobacterium strains that belonged to a specific phylogenetic group. The single-species biofilm was easily washed from the glass surface, whereas the dual-species biofilm strongly adhered after washing. A confocal laser scanning microscopy analysis showed that the dual-species biofilms were significantly thicker and tighter than the single-species biofilms. PMID:25381715

  16. Biofilm Formation by Mycobacterium bovis: Influence of Surface Kind and Temperatures of Sanitizer Treatments on Biofilm Control

    PubMed Central

    Adetunji, Victoria O.; Kehinde, Aderemi O.; Bolatito, Olayemi K.; Chen, Jinru

    2014-01-01

    Mycobacterium bovis causes classic bovine tuberculosis, a zoonosis which is still a concern in Africa. Biofilm forming ability of two Mycobacterium bovis strains was assessed on coupons of cement, ceramic, or stainless steel in three different microbiological media at 37°C with agitation for 2, 3, or 4 weeks to determine the medium that promotes biofilm. Biofilm mass accumulated on coupons was treated with 2 sanitizers (sanitizer A (5.5 mg L−1 active iodine) and sanitizer B (170.6 g1 alkyl dimethylbenzyl ammonium chloride, 78 g−1 didecyldimethyl ammonium chloride, 107.25 g L−1 glutaraldehyde, 146.25 g L−1 isopropanol, and 20 g L−1 pine oil) at 28 and 45°C and in hot water at 85°C for 5 min. Residual biofilms on treated coupons were quantified using crystal violet binding assay. The two strains had a similar ability to form biofilms on the three surfaces. More biofilms were developed in media containing 5% liver extract. Biofilm mass increased as incubation time increased till the 3rd week. More biofilms were formed on cement than on ceramic and stainless steel surfaces. Treatment with hot water at 85°C reduced biofilm mass, however, sanitizing treatments at 45°C removed more biofilms than at 28°C. However, neither treatment completely eliminated the biofilms. The choice of processing surface and temperatures used for sanitizing treatments had an impact on biofilm formation and its removal from solid surfaces. PMID:24991540

  17. Microbial analysis of in situ biofilm formation in drinking water distribution systems: implications for monitoring and control of drinking water quality.

    PubMed

    Douterelo, Isabel; Jackson, M; Solomon, C; Boxall, J

    2016-04-01

    Biofilm formation in drinking water distribution systems (DWDS) is influenced by the source water, the supply infrastructure and the operation of the system. A holistic approach was used to advance knowledge on the development of mixed species biofilms in situ, by using biofilm sampling devices installed in chlorinated networks. Key physico-chemical parameters and conventional microbial indicators for drinking water quality were analysed. Biofilm coverage on pipes was evaluated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The microbial community structure, bacteria and fungi, of water and biofilms was assessed using pyrosequencing. Conventional wisdom leads to an expectation for less microbial diversity in groundwater supplied systems. However, the analysis of bulk water showed higher microbial diversity in groundwater site samples compared with the surface water site. Conversely, higher diversity and richness were detected in biofilms from the surface water site. The average biofilm coverage was similar among sites. Disinfection residual and other key variables were similar between the two sites, other than nitrates, alkalinity and the hydraulic conditions which were extremely low at the groundwater site. Thus, the unexpected result of an exceptionally low diversity with few dominant genera (Pseudomonas and Basidiobolus) in groundwater biofilm samples, despite the more diverse community in the bulk water, is attributed to the low-flow hydraulic conditions. This finding evidences that the local environmental conditions are shaping biofilm formation, composition and amount, and hence managing these is critical for the best operation of DWDS to safeguard water quality. PMID:26637423

  18. 7-hydroxycalamenene Effects on Secreted Aspartic Proteases Activity and Biofilm Formation of Candida spp.

    PubMed Central

    Azevedo, Mariana M. B.; Almeida, Catia A.; Chaves, Francisco C. M.; Rodrigues, Igor A.; Bizzo, Humberto R.; Alviano, Celuta S.; Alviano, Daniela S.

    2016-01-01

    Background: The 7-hydroxycalamenenene-rich essential oil (EO) obtained from the leaves of Croton cajucara (red morphotype) have been described as active against bacteria, protozoa, and fungi species. In this work, we aimed to evaluate the effectiveness of 7-hydroxycalamenenene against Candida albicans and nonalbicans species. Materials and Methods: C. cajucara EO was obtained by hydrodistillation and its major compound, 7-hydroxycalamenene, was purified using preparative column chromatography. The anti-candidal activity was investigated by minimum inhibitory concentration (MIC) and secreted aspartic proteases (SAP) and biofilm inhibition assays. Results: 7-hydroxycalamenene (98% purity) displayed anti-candidal activity against all Candida species tested. Higher activity was observed against Candida dubliniensis, Candida parapsilosis and Candida albicans, showing MIC values ranging from 39.06 μg/ml to 78.12 μg/ml. The purified 7-hydroxycalamenene was able to inhibit 58% of C. albicans ATCC 36801 SAP activity at MIC concentration (pH 7.0). However, 7-hydroxycalamenene demonstrated poor inhibitory activity on C. albicans ATCC 10231 biofilm formation even at the highest concentration tested (2500 μg/ml). Conclusion: The bioactive potential of 7-hydroxycalamenene against planktonic Candida spp. further supports its use for the development of antimicrobials with anti-candidal activity. SUMMARY Croton cajucara Benth. essential oil provides high amounts of 7-hydroxycalamenene7-Hydroxycalameneneisolated from C. cajucarais active against Candida spp7-Hydroxycalameneneinhibits C. albicans aspartic protease activity7-Hydroxycalamenene was not active against C. albicans biofilm formation. Figure

  19. Sfp-type PPTase inactivation promotes bacterial biofilm formation and ability to enhance wheat drought tolerance

    PubMed Central

    Timmusk, Salme; Kim, Seong-Bin; Nevo, Eviatar; Abd El Daim, Islam; Ek, Bo; Bergquist, Jonas; Behers, Lawrence

    2015-01-01

    Paenibacillus polymyxa is a common soil bacterium with broad range of practical applications. An important group of secondary metabolites in P. polymyxa are non-ribosomal peptide and polyketide derived metabolites (NRPs/PKs). Modular non-ribosomal peptide synthetases catalyze main steps in the biosynthesis of the complex secondary metabolites. Here we report on the inactivation of an A26 Sfp-type 4'-phosphopantetheinyl transferase (Sfp-type PPTase). The inactivation of the gene resulted in loss of NRPs/PKs production. In contrast to the former Bacillus spp. model the mutant strain compared to wild type showed greatly enhanced biofilm formation ability. A26Δsfp biofilm promotion is directly mediated by NRPs/PKs, as exogenous addition of the wild type metabolite extracts restores its biofilm formation level. Wheat inoculation with bacteria that had lost their Sfp-type PPTase gene resulted in two times higher plant survival and about three times increased biomass under severe drought stress compared to wild type. Challenges with P. polymyxa genetic manipulation are discussed. PMID:26052312

  20. Role of Alkyl Hydroperoxide Reductase (AhpC) in the Biofilm Formation of Campylobacter jejuni

    PubMed Central

    Oh, Euna; Jeon, Byeonghwa

    2014-01-01

    Biofilm formation of Campylobacter jejuni, a major cause of human gastroenteritis, contributes to the survival of this pathogenic bacterium in different environmental niches; however, molecular mechanisms for its biofilm formation have not been fully understood yet. In this study, the role of oxidative stress resistance in biofilm formation was investigated using mutants defective in catalase (KatA), superoxide dismutase (SodB), and alkyl hydroperoxide reductase (AhpC). Biofilm formation was substantially increased in an ahpC mutant compared to the wild type, and katA and sodB mutants. In contrast to the augmented biofilm formation of the ahpC mutant, a strain overexpressing ahpC exhibited reduced biofilm formation. A perR mutant and a CosR-overexpression strain, both of which upregulate ahpC, also displayed decreased biofilms. However, the introduction of the ahpC mutation to the perR mutant and the CosR-overexpression strain substantially enhanced biofilm formation. The ahpC mutant accumulated more total reactive oxygen species and lipid hydroperoxides than the wild type, and the treatment of the ahpC mutant with antioxidants reduced biofilm formation to the wild-type level. Confocal microscopy analysis showed more microcolonies were developed in the ahpC mutant than the wild type. These results successfully demonstrate that AhpC plays an important role in the biofilm formation of C. jejuni. PMID:24498070

  1. Outer Membrane Vesicles of Helicobacter pylori TK1402 are Involved in Biofilm Formation

    PubMed Central

    2009-01-01

    Background Helicobacter pylori forms biofilms on glass surfaces at the air-liquid interface in in vitro batch cultures; however, biofilms of H. pylori have not been well characterized. In the present study, we analyzed the ability of H. pylori strains to form biofilms and characterized the underlying mechanisms of H. pylori biofilm formation. Results Strain TK1402 showed strong biofilm forming ability relative to the other strains in Brucella broth supplemented with 7% FCS. The strong biofilm forming ability of TK1402 is reflected the relative thickness of the biofilms. In addition, outer membrane vesicles (OMV) were detected within the matrix of only the TK1402 biofilms. Biofilm formation was strongly correlated with the production of OMV in this strain. We further observed that strain TK1402 did not form thick biofilms in Brucella broth supplemented with 0.2% β-cyclodextrin. However, the addition of the OMV-fraction collected from TK1402 could enhance biofilm formation. Conclusion The results suggested that OMV produced from TK1402 play an important role in biofilm formation in strain TK1402. PMID:19751530

  2. Abiotic and microbiotic factors controlling biofilm formation by thermophilic sporeformers.

    PubMed

    Zhao, Yu; Caspers, Martien P M; Metselaar, Karin I; de Boer, Paulo; Roeselers, Guus; Moezelaar, Roy; Nierop Groot, Masja; Montijn, Roy C; Abee, Tjakko; Kort, Remco

    2013-09-01

    One of the major concerns in the production of dairy concentrates is the risk of contamination by heat-resistant spores from thermophilic bacteria. In order to acquire more insight in the composition of microbial communities occurring in the dairy concentrate industry, a bar-coded 16S amplicon sequencing analysis was carried out on milk, final products, and fouling samples taken from dairy concentrate production lines. The analysis of these samples revealed the presence of DNA from a broad range of bacterial taxa, including a majority of mesophiles and a minority of (thermophilic) spore-forming bacteria. Enrichments of fouling samples at 55C showed the accumulation of predominantly Brevibacillus and Bacillus, whereas enrichments at 65C led to the accumulation of Anoxybacillus and Geobacillus species. Bacterial population analysis of biofilms grown using fouling samples as an inoculum indicated that both Anoxybacillus and Geobacillus preferentially form biofilms on surfaces at air-liquid interfaces rather than on submerged surfaces. Three of the most potent biofilm-forming strains isolated from the dairy factory industrial samples, including Geobacillus thermoglucosidans, Geobacillus stearothermophilus, and Anoxybacillus flavithermus, have been characterized in detail with respect to their growth conditions and spore resistance. Strikingly, Geobacillus thermoglucosidans, which forms the most thermostable spores of these three species, is not able to grow in dairy intermediates as a pure culture but appears to be dependent for growth on other spoilage organisms present, probably as a result of their proteolytic activity. These results underscore the importance of abiotic and microbiotic factors in niche colonization in dairy factories, where the presence of thermophilic sporeformers can affect the quality of end products. PMID:23851093

  3. Abiotic and Microbiotic Factors Controlling Biofilm Formation by Thermophilic Sporeformers

    PubMed Central

    Zhao, Yu; Caspers, Martien P. M.; Metselaar, Karin I.; de Boer, Paulo; Roeselers, Guus; Moezelaar, Roy; Nierop Groot, Masja; Montijn, Roy C.; Abee, Tjakko

    2013-01-01

    One of the major concerns in the production of dairy concentrates is the risk of contamination by heat-resistant spores from thermophilic bacteria. In order to acquire more insight in the composition of microbial communities occurring in the dairy concentrate industry, a bar-coded 16S amplicon sequencing analysis was carried out on milk, final products, and fouling samples taken from dairy concentrate production lines. The analysis of these samples revealed the presence of DNA from a broad range of bacterial taxa, including a majority of mesophiles and a minority of (thermophilic) spore-forming bacteria. Enrichments of fouling samples at 55°C showed the accumulation of predominantly Brevibacillus and Bacillus, whereas enrichments at 65°C led to the accumulation of Anoxybacillus and Geobacillus species. Bacterial population analysis of biofilms grown using fouling samples as an inoculum indicated that both Anoxybacillus and Geobacillus preferentially form biofilms on surfaces at air-liquid interfaces rather than on submerged surfaces. Three of the most potent biofilm-forming strains isolated from the dairy factory industrial samples, including Geobacillus thermoglucosidans, Geobacillus stearothermophilus, and Anoxybacillus flavithermus, have been characterized in detail with respect to their growth conditions and spore resistance. Strikingly, Geobacillus thermoglucosidans, which forms the most thermostable spores of these three species, is not able to grow in dairy intermediates as a pure culture but appears to be dependent for growth on other spoilage organisms present, probably as a result of their proteolytic activity. These results underscore the importance of abiotic and microbiotic factors in niche colonization in dairy factories, where the presence of thermophilic sporeformers can affect the quality of end products. PMID:23851093

  4. Extracellular DNA facilitates the formation of functional amyloids in Staphylococcus aureus biofilms.

    PubMed

    Schwartz, Kelly; Ganesan, Mahesh; Payne, David E; Solomon, Michael J; Boles, Blaise R

    2016-01-01

    Persistent staphylococcal infections often involve surface-associated communities called biofilms. Staphylococcus aureus biofilm development is mediated by the co-ordinated production of the biofilm matrix, which can be composed of polysaccharides, extracellular DNA (eDNA) and proteins including amyloid fibers. The nature of the interactions between matrix components, and how these interactions contribute to the formation of matrix, remain unclear. Here we show that the presence of eDNA in S. aureus biofilms promotes the formation of amyloid fibers. Conditions or mutants that do not generate eDNA result in lack of amyloids during biofilm growth despite the amyloidogeneic subunits, phenol soluble modulin peptides, being produced. In vitro studies revealed that the presence of DNA promotes amyloid formation by PSM peptides. Thus, this work exposes a previously unacknowledged interaction between biofilm matrix components that furthers our understanding of functional amyloid formation and S. aureus biofilm biology. PMID:26365835

  5. Extracellular DNA facilitates the formation of functional amyloids in Staphylococcus aureus biofilms

    PubMed Central

    Schwartz, Kelly; Ganesan, Mahesh; Payne, David E.; Solomon, Michael J.; Boles, Blaise R.

    2015-01-01

    Summary Persistent staphylococcal infections often involve surface-associated communities called biofilms. Staphylococcus aureus biofilm development is mediated by the coordinated production of the biofilm matrix, which can be composed of polysaccharides, extracellular DNA (eDNA), and proteins including amyloid fibers. The nature of the interactions between matrix components, and how these interactions contribute to the formation of matrix, remain unclear. Here we show that the presence of eDNA in S. aureus biofilms promotes the formation of amyloid fibers. Conditions or mutants that do not generate eDNA result in lack of amyloids during biofilm growth despite the amyloidogeneic subunits, phenol soluble modulin peptides, being produced. In vitro studies revealed that the presence of DNA promotes amyloid formation by PSM peptides. Thus this work exposes a previously unacknowledged interaction between biofilm matrix components that furthers our understanding of functional amyloid formation and S. aureus biofilm biology. PMID:26365835

  6. Variability in biofilm formation correlates with hydrophobicity and quorum sensing among Vibrio parahaemolyticus isolates from food contact surfaces and the distribution of the genes involved in biofilm formation.

    PubMed

    Mizan, Md Furkanur Rahaman; Jahid, Iqbal Kabir; Kim, Minhui; Lee, Ki-Hoon; Kim, Tae Jo; Ha, Sang-Do

    2016-04-01

    Vibrio parahaemolyticus is one of the leading foodborne pathogens causing seafood contamination. Here, 22 V. parahaemolyticus strains were analyzed for biofilm formation to determine whether there is a correlation between biofilm formation and quorum sensing (QS), swimming motility, or hydrophobicity. The results indicate that the biofilm formation ability of V. parahaemolyticus is positively correlated with cell surface hydrophobicity, autoinducer (AI-2) production, and protease activity. Field emission scanning electron microscopy (FESEM) showed that strong-biofilm-forming strains established thick 3-D structures, whereas poor-biofilm-forming strains produced thin inconsistent biofilms. In addition, the distribution of the genes encoding pandemic clone factors, type VI secretion systems (T6SS), biofilm functions, and the type I pilus in the V. parahaemolyticus seafood isolates were examined. Biofilm-associated genes were present in almost all the strains, irrespective of other phenotypes. These results indicate that biofilm formation on/in seafood may constitute a major factor in the dissemination of V. parahaemolyticus and the ensuing diseases. PMID:26980068

  7. Antibacterial activity of Thymoquinone, an active principle of Nigella sativa and its potency to prevent bacterial biofilm formation

    PubMed Central

    2011-01-01

    Background Thymoquinone is an active principle of Nigella sativa seed known as "Habbah Al-Sauda" in Arabic countries and "Sinouj" in Tunisia. Bacterial biofilms tend to exhibit significant tolerance to antimicrobials drugs during infections. Methods The antibacterial activity of Thymoquinone (TQ) and its biofilm inhibition potencies were investigated on 11 human pathogenic bacteria. The growth and development of the biofilm were assessed using the crystal violet (CV) and the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay. Results TQ exhibited a significant bactericidal activity against the majority of the tested bacteria (MICs values ranged from 8 to 32 ?g/ml) especially Gram positive cocci (Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis CIP 106510). Crystal violet assay demonstrated that the minimum biofilm inhibition concentration (BIC50) was reached with 22 and 60 ?g/ml for Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis CIP 106510 respectively. In addition our data revealed that cells oxidative activity was influenced by TQ supplementation. In the same way, TQ prevented cell adhesion to glass slides surface. Conclusion The ability of TQ to prevent biofilm formation warrants further investigation to explore its use as bioactive substances with antibiofilm potential. PMID:21489272

  8. Analyses of Spatial Distributions of Sulfate-Reducing Bacteria and Their Activity in Aerobic Wastewater Biofilms

    PubMed Central

    Okabe, Satoshi; Itoh, Tsukasa; Satoh, Hisashi; Watanabe, Yoshimasa

    1999-01-01

    The vertical distribution of sulfate-reducing bacteria (SRB) in aerobic wastewater biofilms grown on rotating disk reactors was investigated by fluorescent in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes. To correlate the vertical distribution of SRB populations with their activity, the microprofiles of O2, H2S, NO2?, NO3?, NH4+, and pH were measured with microelectrodes. In addition, a cross-evaluation of the FISH and microelectrode analyses was performed by comparing them with culture-based approaches and biogeochemical measurements. In situ hybridization revealed that a relatively high abundance of the probe SRB385-stained cells (approximately 109 to 1010 cells per cm3 of biofilm) were evenly distributed throughout the biofilm, even in the oxic surface. The probe SRB660-stained Desulfobulbus spp. were found to be numerically important members of SRB populations (approximately 108 to 109 cells per cm3). The result of microelectrode measurements showed that a high sulfate-reducing activity was found in a narrow anaerobic zone located about 150 to 300 ?m below the biofilm surface and above which an intensive sulfide oxidation zone was found. The biogeochemical measurements showed that elemental sulfur (S0) was an important intermediate of the sulfide reoxidation in such thin wastewater biofilms (approximately 1,500 ?m), which accounted for about 75% of the total S pool in the biofilm. The contribution of an internal Fe-sulfur cycle to the overall sulfur cycle in aerobic wastewater biofilms was insignificant (less than 1%) due to the relatively high sulfate reduction rate. PMID:10543829

  9. Constructing multispecies biofilms with defined compositions by sequential deposition of bacteria.

    PubMed

    Stubblefield, Bryan A; Howery, Kristen E; Islam, Bianca N; Santiago, Ariel J; Cardenas, Wendy E; Gilbert, Eric S

    2010-05-01

    Rationally-assembled multispecies biofilms could benefit applied processes including mixed waste biodegradation and drug biosynthesis by combining complementary metabolic pathways into single functional communities. We hypothesized that the cellular composition of mature multispecies biofilms could be manipulated by controlling the number of each cell type present on newly colonized surfaces. To test this idea, we developed a method for attaching specific numbers of bacteria to a flow cell by recirculating cell suspensions. Initial work revealed a nonlinear relationship between suspension cell density and areal density when two strains of Escherichia coli were simultaneously recirculated; in contrast, sequential recirculation resulted in a predictable deposition of cell numbers. Quantitative analysis of cell distributions in 48-h biofilms comprised of the E. coli strains demonstrated a strong relationship between their distribution at the substratum and their presence in mature biofilms. Sequentially depositing E. coli with either Pseudomonas aeruginosa or Bacillus subtilis determined small but reproducible differences in the areal density of the second microorganism recirculated relative to its areal density when recirculated alone. Overall, the presented method offers a simple and reproducible way to construct multispecies biofilms with defined compositions for biocatalytic processes. PMID:20180119

  10. Spatial & Temporal Geophysical Monitoring of Microbial Growth and Biofilm Formation

    NASA Astrophysics Data System (ADS)

    Davis, C. A.; Pyrak-Nolte, L. J.; Atekwana, E. A.; Werkema, D. D.; Haugen, M. E.

    2009-12-01

    Previous studies have examined the effect of biogenic gases and biomineralization on the acoustic properties of porous media. In this study, we investigated the spatiotemporal effect of microbial growth and biofilm formation on compressional waves and complex conductivity in sand columns. A control column (non-biostimulated) and a biostimulated column were studied in a 2D acoustic scanning apparatus, and a second set of columns were constructed with Ag-AgCl electrodes for complex conductivity measurements. At the completion of the 29-day experiment, compressional wave amplitudes and arrival times for the control column were observed to be relatively uniform over the scanned 2D region. However, the biostimulated sample exhibited a high degree of spatial variability within the column for both the amplitude and arrival times. Furthermore, portions of the sample exhibited increased attenuation (~ 80%) concurrent with an increase in the arrival times, while other portions exhibited decreased attenuation (~ 45%) and decreased arrival time. The acoustic amplitude and arrival times changed significantly in the biostimulated column between Days 5 and 7 of the experiment and are consistent with a peak in the imaginary conductivity (σ”) values. The σ” response corresponds to different stages of biofilm development. That is, we interpret the peak σ” with the maximum biofilm thickness and decreasing σ” due to cell death or detachment. Environmental scanning electron microscope (ESEM) imaging confirmed microbial cell attachment to sand surfaces in the biostimulated columns, showed apparent differences in the morphology of attached biomass between regions of increased and decreased attenuation, and indicated no mineral precipitation or biomineralization. The heterogeneity in the elastic properties arises from the differences in the morphology and structure of attached biofilms. These results suggest that combining acoustic imaging and complex conductivity techniques can provide a powerful tool for assessing microbial growth or biofilm formation and the associated changes in porous media, such as those that occur during bioremediation and microbial enhanced oil recovery. Furthermore, this study suggests microbial growth and biofilm development can yield a detectable geophysical response without biomineralization effects. Acknowledgments: This material is based in part on work supported by the National Science Foundation under Grant No. OCE-0729642, EAR 0722410 (MRI), EAR 0525316, and REU Award # 0552918, and EPA Student Services Contract EP07D000660. LJPN would like to acknowledge support from Geosciences Research Program, Office of Basic Energy Sciences, US Department of Energy (DEFG02-97ER14785 08).

  11. Pseudomonas aeruginosa Promotes Escherichia coli Biofilm Formation in Nutrient-Limited Medium

    PubMed Central

    Culotti, Alessandro; Packman, Aaron I.

    2014-01-01

    Biofilms have been implicated as an important reservoir for pathogens and commensal enteric bacteria such as Escherichia coli in natural and engineered water systems. However, the processes that regulate the survival of E. coli in aquatic biofilms have not been thoroughly studied. We examined the effects of hydrodynamic shear and nutrient concentrations on E. coli colonization of pre-established Pseudomonas aeruginosa biofilms, co-inoculation of E. coli and P. aeruginosa biofilms, and P. aeruginosa colonization of pre-established E. coli biofilms. In nutritionally-limited R2A medium, E. coli dominated biofilms when co-inoculated with P. aeruginosa, and successfully colonized and overgrew pre-established P. aeruginosa biofilms. In more enriched media, P. aeruginosa formed larger clusters, but E. coli still extensively overgrew and colonized the interior of P. aeruginosa clusters. In mono-culture, E. coli formed sparse and discontinuous biofilms. After P. aeruginosa was introduced to these biofilms, E. coli growth increased substantially, resulting in patterns of biofilm colonization similar to those observed under other sequences of organism introduction, i.e., E. coli overgrew P. aeruginosa and colonized the interior of P. aeruginosa clusters. These results demonstrate that E. coli not only persists in aquatic biofilms under depleted nutritional conditions, but interactions with P. aeruginosa can greatly increase E. coli growth in biofilms under these experimental conditions. PMID:25198725

  12. Biofilm in endodontics: A review

    PubMed Central

    Jhajharia, Kapil; Parolia, Abhishek; Shetty, K Vikram; Mehta, Lata Kiran

    2015-01-01

    Endodontic disease is a biofilm-mediated infection, and primary aim in the management of endodontic disease is the elimination of bacterial biofilm from the root canal system. The most common endodontic infection is caused by the surface-associated growth of microorganisms. It is important to apply the biofilm concept to endodontic microbiology to understand the pathogenic potential of the root canal microbiota as well as to form the basis for new approaches for disinfection. It is foremost to understand how the biofilm formed by root canal bacteria resists endodontic treatment measures. Bacterial etiology has been confirmed for common oral diseases such as caries and periodontal and endodontic infections. Bacteria causing these diseases are organized in biofilm structures, which are complex microbial communities composed of a great variety of bacteria with different ecological requirements and pathogenic potential. The biofilm community not only gives bacteria effective protection against the host's defense system but also makes them more resistant to a variety of disinfecting agents used as oral hygiene products or in the treatment of infections. Successful treatment of these diseases depends on biofilm removal as well as effective killing of biofilm bacteria. So, the fundamental to maintain oral health and prevent dental caries, gingivitis, and periodontitis is to control the oral biofilms. From these aspects, the formation of biofilms carries particular clinical significance because not only host defense mechanisms but also therapeutic efforts including chemical and mechanical antimicrobial treatment measures have the most difficult task of dealing with organisms that are gathered in a biofilm. The aim of this article was to review the