Sample records for calgary biofilm device
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Characterization of Pleurotus ostreatus biofilms by using the calgary biofilm device.
Pesciaroli, Lorena; Petruccioli, Maurizio; Fedi, Stefano; Firrincieli, Andrea; Federici, Federico; D'Annibale, Alessandro
2013-10-01
The adequacy of the Calgary biofilm device, often referred to as the MBEC system, as a high-throughput approach to the production and subsequent characterization of Pleurotus ostreatus biofilms was assessed. The hydroxyapatite-coating of pegs was necessary to enable biofilm attachment, and the standardization of vegetative inocula ensured a uniform distribution of P. ostreatus biofilms, which is necessary for high-throughput evaluations of several antimicrobials and exposure conditions. Scanning electron microscopy showed surface-associated growth, the occurrence of a complex aggregated growth organized in multilayers or hyphal bundles, and the encasement of hyphae within an extracellular matrix (ECM), the extent of which increased with time. Chemical analyses showed that biofilms differed from free-floating cultures for their higher contents of total sugars (TS) and ECM, with the latter being mainly composed of TS and, to a lesser extent, protein. Confocal laser scanning microscopy analysis of 4-day-old biofilms showed the presence of interspersed interstitial voids and water channels in the mycelial network, the density and compactness of which increased after a 7-day incubation, with the novel occurrence of ECM aggregates with an α-glucan moiety. In 4- and 7-day-old biofilms, tolerance to cadmium was increased by factors of 3.2 and 11.1, respectively, compared to coeval free-floating counterparts.
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Characterization of Pleurotus ostreatus Biofilms by Using the Calgary Biofilm Device
Pesciaroli, Lorena; Petruccioli, Maurizio; Fedi, Stefano; Firrincieli, Andrea; Federici, Federico
2013-01-01
The adequacy of the Calgary biofilm device, often referred to as the MBEC system, as a high-throughput approach to the production and subsequent characterization of Pleurotus ostreatus biofilms was assessed. The hydroxyapatite-coating of pegs was necessary to enable biofilm attachment, and the standardization of vegetative inocula ensured a uniform distribution of P. ostreatus biofilms, which is necessary for high-throughput evaluations of several antimicrobials and exposure conditions. Scanning electron microscopy showed surface-associated growth, the occurrence of a complex aggregated growth organized in multilayers or hyphal bundles, and the encasement of hyphae within an extracellular matrix (ECM), the extent of which increased with time. Chemical analyses showed that biofilms differed from free-floating cultures for their higher contents of total sugars (TS) and ECM, with the latter being mainly composed of TS and, to a lesser extent, protein. Confocal laser scanning microscopy analysis of 4-day-old biofilms showed the presence of interspersed interstitial voids and water channels in the mycelial network, the density and compactness of which increased after a 7-day incubation, with the novel occurrence of ECM aggregates with an α-glucan moiety. In 4- and 7-day-old biofilms, tolerance to cadmium was increased by factors of 3.2 and 11.1, respectively, compared to coeval free-floating counterparts. PMID:23892744
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Effect of ototopical medications on tympanostomy tube biofilms.
Oxley, K Scott; Thomas, John G; Ramadan, Hassan H
2007-10-01
Examine how ototopical medications affect biofilms on fluoroplastic tympanostomy tubes. In vitro comparison of different ototopical medications against a clinical isolate of Pseudomonas aeruginosa biofilm on tympanostomy tubes treated for 5, 10, 14, and 21 days. Under sterile conditions 21 tympanostomy tubes were cut in half. These were attached to pegs of two Calgary Biofilm Devices via rubber cement. Device 1 evaluated microbial growth as colony forming units (CFUs). Device 2 evaluated presence of biofilms. Tubes were prepped for biofilm growth, incubated, and stressed for 72 hours. Afterward, one tube per device was removed and forcefully washed. One was sonificated for 5 minutes, serially diluted, and plated for CFUs. Formalin preserved the other for biofilm evaluation by scanning electron microscopy. Next, tubes were exposed to five drops of Ciprofloxacin, Ciprofloxacin/Dexamethasone, Dexamethasone, Ofloxacin, or saline for 1 hour. Afterward, the ototopicals were removed and sterile broth was placed in the wells as a nutrient. This was repeated every 12 hours for 5, 10, 14, and 21 days of treatment. Prior to the last dose of treatment intervals, a streak plate was performed to evaluate for microbial growth in the wells. The tubes were evaluated for CFUs and biofilms at each interval as previously described. Microbial activity in CFUs decreased by day 5 and continued through day 21 for the antibiotic containing drops. Despite treatment, the biofilm was never eradicated and continued to progress. Infectivity of the biofilm is neutralized by antibiotic ototopicals; however, the biofilm will progress despite treatment.
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Laser-generated shockwave for clearing medical device biofilms.
Kizhner, Victor; Krespi, Yosef P; Hall-Stoodley, Luanne; Stoodley, Paul
2011-04-01
This study aimed to evaluate a laser method of biofilm interruption from the surface of various common medical devices and from surgically removed sinus tissue with adherent biofilms in a timely manner. Biofilm has emerged as a new threat not amenable to most antibiotic treatments. Biofilms, as opposed to planktonic bacteria, develop an extracellular polymeric slime matrix to facilitate adherence to host tissue or a prosthetic surface and to form a protective shield. A laser-induced biofilms disruption concept was previously described. Biofilms were grown in the laboratory on metallic and plastic medical device surfaces such as stents. Attempts to remove the biofilms with a laser were undertaken three times for each device. Q-switched Nd:YAG laser-generated shockwaves affecting Pseudomonas aeruginosa biofilms expressing yellow fluorescent protein (YFP) biofilm coating were applied with biologically safe parameters utilizing a fiber delivery system and a special probe. A confocal microscope was used to identify the biofilm structure prior to, during, and after laser application. The amount of biofilm removed from the medical devices in time was measured by quantifying green fluorescence. The biofilm fluctuated and eventually broke off the surface as shock waves neared the target. The time to remove 97.9 ± 0.4% (mean ± 1SD, n = 3) the biofilm from the surface of a Nitinol (NiTi) stent ranged from 4 to 10 s. The detached biofilm was observed floating in fluid media in various microscopic size particles. A new treatment modality using laser-generated shockwaves in the warfare against biofilms growing on surgical devices was demonstrated. Q-switched laser pulses stripped biofilm from the surface it adhered to, changing the bacteria to their planktonic form, making them amenable to conventional treatment. This therapeutic modality appears to be rapid, effective, and safe on metallic and plastic medical device surfaces.
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Peyton, Brent M.; Truex, Michael J.
1997-01-01
An apparatus for characterization of in-situ microbial biofilm populations in subsurface groundwater. The device permits biofilm-forming microorganisms to adhere to packing material while emplaced in a groundwater strata, so that the packing material can be later analyzed for quantity and type of microorganisms, growth rate, and nutrient requirements.
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Peyton, B.M.; Truex, M.J.
1997-06-24
An apparatus is disclosed for characterization of in-situ microbial biofilm populations in subsurface groundwater. The device permits biofilm-forming microorganisms to adhere to packing material while emplaced in a groundwater strata, so that the packing material can be later analyzed for quantity and type of microorganisms, growth rate, and nutrient requirements. 3 figs.
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Decontamination Efficacy of Ultraviolet Radiation against Biofilms of Common Nosocomial Bacteria.
Tingpej, Pholawat; Tiengtip, Rattana; Kondo, Sumalee
2015-06-01
Ultraviolet radiation (UV) is commonly used to destroy microorganisms in the health-care environment. However, the efficacy of UV radiation against bacteria growing within biofilms has never been studied. To measure the sterilization effectiveness of UV radiation against common healthcare associated pathogens growing within biofilms. Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), Streptococcus epidermidis, Escherichia coli, ESBL-producing E. coli, Pseudomonas aeruginosa and Acinetobacter baumannii were cultivated in the Calgary Biofilm Device. Their biofilms were placed 50 cm from the UV lamp within the Biosafety Cabinet. Viability test, crystal violet assay and a scanning electron microscope were used to evaluate the germicidal efficacy. Within 5 minutes, UV radiation could kill S. aureus, MRSA, S. epidermidis, A. baumannii and ESBL-producing E. coli completely while it required 20 minutes and 30 minutes respectively to kill E. coli and P. aeruginosa. However, the amounts of biomass and the ultrastructure between UV-exposed biofilms and controls were not significantly different. UV radiation is effective in inactivating nosocomial pathogens grown within biofilms, but not removing biofilms and EPS. The biofilm of P. aeruginosa was the most durable.
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2015-01-01
Calgary Laboratory Services provides global hospital and community laboratory services for Calgary and surrounding areas (population 1.4 million) and global academic support for the University of Calgary Cumming School of Medicine. It developed rapidly after the Alberta Provincial Government implemented an austerity program to address rising health care costs and to address Alberta’s debt and deficit in 1994. Over roughly the next year, all hospital and community laboratory test funding within the province was put into a single budget, fee codes for fee-for-service test billing were closed, roughly 40% of the provincial laboratory budget was cut, and roughly 40% of the pathologists left the province of Alberta. In Calgary, in the face of these abrupt changes in the laboratory environment, private laboratories, publicly funded hospital laboratories and the medical school department precipitously and reluctantly merged in 1996. The origin of Calgary Laboratory Services was likened to an “unhappy shotgun marriage” by all parties. Although such a structure could save money by eliminating duplicated services and excess capacity and could provide excellent city-wide clinical service by increasing standardization, it was less clear whether it could provide strong academic support for a medical school. Over the past decade, iterations of the Calgary Laboratory Services model have been implemented or are being considered in other Canadian jurisdictions. This case study analyzes the evolution of Calgary Laboratory Services, provides a metric-based review of academic performance over time, and demonstrates that this model, essentially arising as an unplanned experiment, has merit within a Canadian health care context. PMID:28725754
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Gomes, Inês B; Meireles, Ana; Gonçalves, Ana L; Goeres, Darla M; Sjollema, Jelmer; Simões, Lúcia C; Simões, Manuel
2018-08-01
Biofilms can cause severe problems to human health due to the high tolerance to antimicrobials; consequently, biofilm science and technology constitutes an important research field. Growing a relevant biofilm in the laboratory provides insights into the basic understanding of the biofilm life cycle including responses to antibiotic therapies. Therefore, the selection of an appropriate biofilm reactor is a critical decision, necessary to obtain reproducible and reliable in vitro results. A reactor should be chosen based upon the study goals and a balance between the pros and cons associated with its use and operational conditions that are as similar as possible to the clinical setting. However, standardization in biofilm studies is rare. This review will focus on the four reactors (Calgary biofilm device, Center for Disease Control biofilm reactor, drip flow biofilm reactor, and rotating disk reactor) approved by a standard setting organization (ASTM International) for biofilm experiments and how researchers have modified these standardized reactors and associated protocols to improve the study and understanding of medical biofilms.
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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.
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Adhesion and formation of microbial biofilms in complex microfluidic devices
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kumar, Aloke; Karig, David K; Neethirajan, Suresh
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 inmore » 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.« less
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Evaluation of microbial biofilm communities from an Alberta oil sands tailings pond.
Golby, Susanne; Ceri, Howard; Gieg, Lisa M; Chatterjee, Indranil; Marques, Lyriam L R; Turner, Raymond J
2012-01-01
Bitumen extraction from the oil sands of Alberta has resulted in millions of cubic meters of waste stored on-site in tailings ponds. Unique microbial ecology is expected in these ponds, which may be key to their bioremediation potential. We considered that direct culturing of microbes from a tailings sample as biofilms could lead to the recovery of microbial communities that provide good representation of the ecology of the tailings. Culturing of mixed species biofilms in vitro using the Calgary Biofilm Device (CBD) under aerobic, microaerobic, and anaerobic growth conditions was successful both with and without the addition of various growth nutrients. Denaturant gradient gel electrophoresis and 16S rRNA gene pyrotag sequencing revealed that unique mixed biofilm communities were recovered under each incubation condition, with the dominant species belonging to Pseudomonas, Thauera, Hydrogenophaga, Rhodoferax, and Acidovorax. This work used an approach that allowed organisms to grow as a biofilm directly from a sample collected of their environment, and the biofilms cultivated in vitro were representative of the endogenous environmental community. For the first time, representative environmental mixed species biofilms have been isolated and grown under laboratory conditions from an oil sands tailings pond environment and a description of their composition is provided.
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Monitoring biofilm attachment on medical devices surfaces using hyperspectral imaging
NASA Astrophysics Data System (ADS)
Le, Hanh N. D.; Hitchins, Victoria M.; Ilev, Ilko K.; Kim, Do-Hyun
2014-02-01
Microbial biofilm is a colony of single bacteria cells (planktonic) that attached to surfaces, attract other microorganisms to attach and grow, and together they build an extracellular matrix composed of polysaccharides, protein, and DNA. Eventually, some cells will detach and spread to other surface. Biofilm on medical devices can cause severe infection to all age ranges from infant to adult. Therefore, it is important to detect biofilm in a fast and efficient manner. Hyperspectral imaging was utilized for distinguishing wide area of biofilm coverage on various materials and on different textures of stainless steeltest coupons. Not only is the coverage of biofilm important, but also the shear stress of biofilm on the attached surfaces is significant. This study investigates the effects of shear stress on the adhesion of biofilms on common medical device surfaces such as glass, polycarbonate, polytetrafluoroethylene, and stainless steel with different textures. Biofilm was grown using Ps. aeruginosa and growth was monitored after 24 and 48 hours at 37° C. The coupons covered with biofilm were tilted at 45 degrees and 90 degrees for 30 seconds to induce shear stress and Hyperspectral images were taken. We hypothesize that stronger attachment on rough surface would be able to withstand greater shear stress compared to smooth surface.
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Microscale Confinement features in microfluidic devices can affect biofilm
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kumar, Aloke; Karig, David K; Neethirajan, Suresh
2013-01-01
Biofilms are aggregations of microbes that are encased by extra-cellular polymeric substances (EPS) and adhere to surfaces and interfaces. Biofilm development on abiotic surfaces is a dynamic process, which typically proceeds through an initial phase of adhesion of plankntonic microbes to the substrate, followed by events such as growth, maturation and EPS secretion. However, the coupling of hydrodynamics, microbial adhesion and biofilm growth remain poorly understood. Here, we investigate the effect of semiconfined features on biofilm formation. Using a microfluidic device and fluorescent time-lapse microscopy, we establish that confinement features can significantly affect biofilm formation. Biofilm dynamics change not onlymore » as a function of confinement features, but also of the total fluid flow rate, and our combination of experimental results and numerical simulations reveal insights into the link between hydrodynamics and biofilm formation.« less
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Biofilm-forming capacity of blood-borne Candida albicans strains and effects of antifungal agents.
Turan, Hanni; Demirbilek, Müge
Infections related to Candida albicans biofilms and subsequent antifungal resistance have become more common with the increased use of indwelling medical devices. Regimens for preventing fungal biofilm formation are needed, particularly in high-risk patients. In this study, we investigated the biofilm formation rate of multiple strains of Candida albicans (n=162 clinical isolates), their antifungal susceptibility patterns, and the efficacy of certain antifungals for preventing biofilm formation. Biofilm formation was graded using a modified Christensen's 96-well plate method. We further analyzed 30 randomly chosen intense biofilm-forming isolates using the XTT method. Minimum biofilm inhibition concentrations (MBIC) of caspofungin, micafungin, anidulafungin, fluconazole, voriconazole, posaconazole, itraconazole, and amphotericin B were determined using the modified Calgary biofilm method. In addition, the inhibitory effects of antifungal agents on biofilm formation were investigated. Our study showed weak, moderate, and extensive biofilm formation in 29% (n=47), 38% (n=61), and 23% (n=37) of the isolates, respectively. We found that echinocandins had the lowest MBIC values and that itraconazole inhibited biofilm formation in more isolates (26/32; 81.3%) than other tested agents. In conclusion, echinocandins were most effective against formed biofilms, while itraconazole was most effective for preventing biofilm formation. Standardized methods are needed for biofilm antifungal sensitivity tests when determining the treatment and prophylaxis of C. albicans infections. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.
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Harrison, Joe J; Ceri, Howard; Yerly, Jerome; Rabiei, Maryam; Hu, Yaoping; Martinuzzi, Robert; Turner, Raymond J
2007-08-01
Candida albicans and Candida tropicalis are polymorphic fungi that develop antimicrobial-resistant biofilm communities that are characterized by multiple cell morphotypes. This study investigated cell type interconversion and drug and metal resistance as well as community organization in biofilms of these microorganisms that were exposed to metal ions. To study this, Candida biofilms were grown either in microtiter plates containing gradient arrays of metal ions or in the Calgary Biofilm Device for high-throughput susceptibility testing. Biofilm formation and antifungal resistance were evaluated by viable cell counts, tetrazolium salt reduction, light microscopy, and confocal laser scanning microscopy in conjunction with three-dimensional visualization. We discovered that subinhibitory concentrations of certain metal ions (CrO(4)(2-), Co(2+), Cu(2+), Ag(+), Zn(2+), Cd(2+), Hg(2+), Pb(2+), AsO(2)(-), and SeO(3)(2-)) caused changes in biofilm structure by blocking or eliciting the transition between yeast and hyphal cell types. Four distinct biofilm community structure types were discerned from these data, which were designated "domed," "layer cake," "flat," and "mycelial." This study suggests that Candida biofilm populations may respond to metal ions to form cell-cell and solid-surface-attached assemblages with distinct patterns of cellular differentiation.
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NASA Astrophysics Data System (ADS)
Kim, Do-Hyun; Kim, Moon S.; Hwang, Jeeseong
2012-03-01
Contamination of the inner surface of indwelling (implanted) medical devices by microbial biofilm is a serious problem. Some microbial bacteria such as Escherichia coli form biofilms that lead to potentially lifethreatening infections. Other types of medical devices such as bronchoscopes and duodenoscopes account for the highest number of reported endoscopic infections where microbial biofilm is one of the major causes for these infections. We applied a hyperspectral imaging method to detect biofilm contamination on the surface of several common materials used for medical devices. Such materials include stainless steel, titanium, and stainless-steeltitanium alloy. Potential uses of hyperspectral imaging technique to monitor biofilm attachment to different material surfaces are discussed.
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Comparing the Effectiveness of Polymer Debriding Devices Using a Porcine Wound Biofilm Model.
Wilkinson, Holly N; McBain, Andrew J; Stephenson, Christian; Hardman, Matthew J
2016-11-01
Objective: Debridement to remove necrotic and/or infected tissue and promote active healing remains a cornerstone of contemporary chronic wound management. While there has been a recent shift toward less invasive polymer-based debriding devices, their efficacy requires rigorous evaluation. Approach: This study was designed to directly compare monofilament debriding devices to traditional gauze using a wounded porcine skin biofilm model with standardized application parameters. Biofilm removal was determined using a surface viability assay, bacterial counts, histological assessment, and scanning electron microscopy (SEM). Results: Quantitative analysis revealed that monofilament debriding devices outperformed the standard gauze, resulting in up to 100-fold greater reduction in bacterial counts. Interestingly, histological and morphological analyses suggested that debridement not only removed bacteria, but also differentially disrupted the bacterially-derived extracellular polymeric substance. Finally, SEM of post-debridement monofilaments showed structural changes in attached bacteria, implying a negative impact on viability. Innovation: This is the first study to combine controlled and defined debridement application with a biologically relevant ex vivo biofilm model to directly compare monofilament debriding devices. Conclusion: These data support the use of monofilament debriding devices for the removal of established wound biofilms and suggest variable efficacy towards biofilms composed of different species of bacteria.
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Comparing the Effectiveness of Polymer Debriding Devices Using a Porcine Wound Biofilm Model
Wilkinson, Holly N.; McBain, Andrew J.; Stephenson, Christian; Hardman, Matthew J.
2016-01-01
Objective: Debridement to remove necrotic and/or infected tissue and promote active healing remains a cornerstone of contemporary chronic wound management. While there has been a recent shift toward less invasive polymer-based debriding devices, their efficacy requires rigorous evaluation. Approach: This study was designed to directly compare monofilament debriding devices to traditional gauze using a wounded porcine skin biofilm model with standardized application parameters. Biofilm removal was determined using a surface viability assay, bacterial counts, histological assessment, and scanning electron microscopy (SEM). Results: Quantitative analysis revealed that monofilament debriding devices outperformed the standard gauze, resulting in up to 100-fold greater reduction in bacterial counts. Interestingly, histological and morphological analyses suggested that debridement not only removed bacteria, but also differentially disrupted the bacterially-derived extracellular polymeric substance. Finally, SEM of post-debridement monofilaments showed structural changes in attached bacteria, implying a negative impact on viability. Innovation: This is the first study to combine controlled and defined debridement application with a biologically relevant ex vivo biofilm model to directly compare monofilament debriding devices. Conclusion: These data support the use of monofilament debriding devices for the removal of established wound biofilms and suggest variable efficacy towards biofilms composed of different species of bacteria. PMID:27867752
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Gugala, Natalie; Lemire, Joe A; Turner, Raymond J
2017-06-01
The emergence of multidrug-resistant pathogens and the prevalence of biofilm-related infections have generated a demand for alternative anti-microbial therapies. Metals have not been explored in adequate detail for their capacity to combat infectious disease. Metal compounds can now be found in textiles, medical devices and disinfectants-yet, we know little about their efficacy against specific pathogens. To help fill this knowledge gap, we report on the anti-microbial and antibiofilm activity of seven metals: silver, copper, titanium, gallium, nickel, aluminum and zinc against three bacterial strains, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. To evaluate the capacity of metal ions to prevent the growth of, and eradicate biofilms and planktonic cells, bacterial cultures were inoculated in the Calgary Biofilm Device (minimal biofilm eradication concentration) in the presence of the metal salts. Copper, gallium and titanium were capable of preventing planktonic and biofilm growth, and eradicating established biofilms of all tested strains. Further, we observed that the efficacies of the other tested metal salts displayed variable efficacy against the tested strains. Further, contrary to the enhanced resistance anticipated from bacterial biofilms, particular metal salts were observed to be more effective against biofilm communities versus planktonic cells. In this study, we have demonstrated that the identity of the bacterial strain must be considered before treatment with a particular metal ion. Consequent to the use of metal ions as anti-microbial agents to fight multidrug-resistant and biofilm-related infections increases, we must aim for more selective deployment in a given infectious setting.
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Revdiwala, Sangita; Rajdev, Bhaumesh M; Mulla, Summaiya
2012-01-01
Background. Biofilms contaminate catheters, ventilators, and medical implants; they act as a source of disease for humans, animals, and plants. Aim. Critical care units of any healthcare institute follow various interventional strategies with use of medical devices for the management of critical cases. Bacteria contaminate medical devices and form biofilms. Material and Methods. The study was carried out on 100 positive bacteriological cultures of medical devices which were inserted in hospitalized patients. The bacterial isolates were processed as per microtitre plate. All the isolates were subjected to antibiotic susceptibility testing by VITEK 2 compact automated systems. Results. Out of the total 100 bacterial isolates tested, 88 of them were biofilm formers. A 16-20-hour incubation period was found to be optimum for biofilm development. 85% isolates were multidrug resistants and different mechanisms of bacterial drug resistance like ESBL, carbapenemase, and MRSA were found among isolates. Conclusion. Availability of nutrition in the form of glucose enhances the biofilm formation by bacteria. Time and availability of glucose are important factors for assessment of biofilm progress. It is an alarm for those who are associated with invasive procedures and indwelling medical devices especially in patients with low immunity.
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Development and pyrosequencing analysis of an in-vitro oral biofilm model.
Kistler, James O; Pesaro, Manuel; Wade, William G
2015-02-10
Dental caries and periodontal disease are the commonest bacterial diseases of man and can result in tooth loss. The principal method of prevention is the mechanical removal of dental plaque augmented by active agents incorporated into toothpastes and mouthrinses. In-vitro assays that include complex oral bacterial biofilms are required to accurately predict the efficacy of novel active agents in vivo. The aim of this study was to develop an oral biofilm model using the Calgary biofilm device (CBD) seeded with a natural saliva inoculum and analysed by next generation sequencing. The specific objectives were to determine the reproducibility and stability of the model by comparing the composition of the biofilms over time derived from (i) the same volunteers at different time points, and (ii) different panels of volunteers. Pyrosequencing yielded 280,093 sequences with a mean length of 432 bases after filtering. A mean of 320 and 250 OTUs were detected in pooled saliva and biofilm samples, respectively. Principal coordinates analysis (PCoA) plots based on community membership and structure showed that replicate biofilm samples were highly similar and clustered together. In addition, there were no significant differences between biofilms derived from the same panel at different times using analysis of molecular variance (AMOVA). There were significant differences between biofilms from different panels (AMOVA, P < 0.002). PCoA revealed that there was a shift in biofilm composition between seven and 14 days (AMOVA, P < 0.001). Veillonella parvula, Veillonella atypica/dispar/parvula and Peptostreptococcus stomatis were the predominant OTUs detected in seven-day biofilms, whilst Prevotella oralis, V. parvula and Streptococcus constellatus were predominant in 14-day biofilms. Diverse oral biofilms were successfully grown and maintained using the CBD. Biofilms derived from the same panel of volunteers were highly reproducible. This model could be used to screen both
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Okuda, Ken-Ichi; Nagahori, Ryuichi; Yamada, Satomi; Sugimoto, Shinya; Sato, Chikara; Sato, Mari; Iwase, Tadayuki; Hashimoto, Kazuhiro; Mizunoe, Yoshimitsu
2018-01-01
The present study aimed to understand the biofilm formation mechanism of Propionibacterium acnes by analyzing the components and structure of the biofilms. P. acnes strains were isolated from the surface of explanted cardiac pacemaker devices that exhibited no clinical signs of infection. Culture tests using a simple stamp culture method (pressing pacemakers against the surface of agar plates) revealed frequent P. acnes colonization on the surface of cardiac pacemaker devices. P . acnes was isolated from 7/31 devices, and the isolates were categorized by multilocus sequence typing into five different sequence types (STs): ST4 (JK18.2), ST53 (JK17.1), ST69 (JK12.2 and JK13.1), ST124 (JK5.3), ST125 (JK6.2), and unknown ST (JK19.3). An in vitro biofilm formation assay using microtiter plates demonstrated that 5/7 isolates formed biofilms. Inhibitory effects of DNase I and proteinase K on biofilm formation varied among isolates. In contrast, dispersin B showed no inhibitory activity against all isolates. Three-dimensional live/dead imaging of P. acnes biofilms with different biochemical properties using confocal laser microscopy demonstrated different distributions and proportions of living and dead cells. Additionally, it was suggested that extracellular DNA (eDNA) plays a role in the formation of biofilms containing living cells. Ultrastructural analysis of P. acnes biofilms using a transmission electron microscope and atmospheric scanning electron microscope revealed leakage of cytoplasmic components along with cell lysis and fibrous structures of eDNA connecting cells. In conclusion, the biochemical properties and structures of the biofilms differed among P. acnes isolates. These findings may provide clues for establishing countermeasures against biofilm-associated infection by P. acnes .
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Early medicine and surgery in Calgary.
Troy, M T
1976-09-01
The medical history of the Calgary area can be divided into three periods: the early period before the coming of the North West Mounted Police in 1874, the middle period from 1875 to 1905, during which Fort Calgary was built and the first surgeons settled in the West, and the third period from 1905 to the present. George Alexander Kennedy was the first surgeon of the middle period. He encouraged proper sanitation, fresh air, and avoidance of cold, damp and dirt. He recommended special treatment for various systemic diseases, used chloroform in October 1880 and was known to have treated skull fractures, extradural hemorrhages, prostatic obstruction, postabortion hemorrhage, ascites and pleural effusion. Henderson, Brett, Lindsay, Rouleau, Lafferty and Mackid were the other six pioneer surgeons of the middle period. Mackid's son Ludwig took over his father's practice after studying in Europe and the United States. When he died in November 1975 at the age of 93, the last link with the pioneer surgeons of Calgary was broken.
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Fujimura, Shigeru; Sato, Tetsuro; Mikami, Takeshi; Kikuchi, Toshiaki; Gomi, Kazunori; Watanabe, Akira
2008-12-01
In this study, we investigated the in vitro efficacy of clarithromycin (CLA) combined with cefazolin (CFZ) or vancomycin (VCM) against Staphylococcus aureus biofilms formed on titanium devices in order to confirm the efficacy of eradication therapies against device-related infection. The distribution of CLA in muscle tissue surrounding bone was also investigated by liquid chromatography/tandem mass spectrometry in 10 orthopaedic patients. Biofilm formation and eradication of S. aureus were monitored by scanning electron microscopy and using double-staining dyes, respectively. Although S. aureus biofilms were not eradicated by CLA, CFZ or VCM alone, CLA combined with CFZ or VCM destroyed biofilms, and S. aureus eradication was clearly observed 72 h later. This in vitro study showed that treatment with CLA plus CFZ or VCM destroyed staphylococcal biofilms formed on medical devices and eradicated S. aureus.
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Okuda, Ken-ichi; Nagahori, Ryuichi; Yamada, Satomi; Sugimoto, Shinya; Sato, Chikara; Sato, Mari; Iwase, Tadayuki; Hashimoto, Kazuhiro; Mizunoe, Yoshimitsu
2018-01-01
The present study aimed to understand the biofilm formation mechanism of Propionibacterium acnes by analyzing the components and structure of the biofilms. P. acnes strains were isolated from the surface of explanted cardiac pacemaker devices that exhibited no clinical signs of infection. Culture tests using a simple stamp culture method (pressing pacemakers against the surface of agar plates) revealed frequent P. acnes colonization on the surface of cardiac pacemaker devices. P. acnes was isolated from 7/31 devices, and the isolates were categorized by multilocus sequence typing into five different sequence types (STs): ST4 (JK18.2), ST53 (JK17.1), ST69 (JK12.2 and JK13.1), ST124 (JK5.3), ST125 (JK6.2), and unknown ST (JK19.3). An in vitro biofilm formation assay using microtiter plates demonstrated that 5/7 isolates formed biofilms. Inhibitory effects of DNase I and proteinase K on biofilm formation varied among isolates. In contrast, dispersin B showed no inhibitory activity against all isolates. Three-dimensional live/dead imaging of P. acnes biofilms with different biochemical properties using confocal laser microscopy demonstrated different distributions and proportions of living and dead cells. Additionally, it was suggested that extracellular DNA (eDNA) plays a role in the formation of biofilms containing living cells. Ultrastructural analysis of P. acnes biofilms using a transmission electron microscope and atmospheric scanning electron microscope revealed leakage of cytoplasmic components along with cell lysis and fibrous structures of eDNA connecting cells. In conclusion, the biochemical properties and structures of the biofilms differed among P. acnes isolates. These findings may provide clues for establishing countermeasures against biofilm-associated infection by P. acnes. PMID:29491850
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Teles, Flavia; Starr, Jacqueline R.; Feres, Magda; Patel, Michele; Martin, Lynn
2015-01-01
Chronic periodontitis is one of the most prevalent human diseases and is caused by dysbiosis of the subgingival microbiota. Treatment involves primarily mechanical disruption of subgingival biofilms and, in certain cases, adjunctive use of systemic antibiotic therapy. In vitro biofilm models have been developed to study antimicrobial agents targeting subgingival species. However, these models accommodate a limited number of taxa, lack reproducibility, and have low throughput. We aimed to develop an in vitro multispecies biofilm model that mimics subgingival plaque, to test antimicrobial agents. Biofilms were cultivated using the Calgary Biofilm Device and were exposed to amoxicillin (AMX), metronidazole (MTZ), azithromycin (AZM), and AMX-MTZ at four different concentrations for 12, 24, or 36 h. Chlorhexidine (CHX) (0.12%) was used as the positive control. The compositions of the biofilms were analyzed by checkerboard DNA-DNA hybridization, and the percent reduction in biofilm metabolic activity was determined using 2,3,5-triphenyltetrazolium chloride and spectrophotometry. Thirty-five of the 40 species used in the inoculum were consistently recovered from the resulting in vitro biofilms. After 36 h of exposure at the 1:27 dilution, AMX-MTZ reduced metabolic activity 11% less than CHX (q = 0.0207) but 54% more than AMX (q = 0.0031), 72% more than MTZ (q = 0.0031), and 67% more than AZM (q = 0.0008). Preliminary evidence of a synergistic interaction between AMX and MTZ was also observed. In summary, we developed reproducible biofilms with 35 subgingival bacterial species, and our results suggested that the combination of AMX and MTZ had greater antimicrobial effects on these in vitro multispecies biofilms than expected on the basis of the independent effects of the drugs. PMID:25733510
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Inhibition of Biofilm Formation by Esomeprazole in Pseudomonas aeruginosa and Staphylococcus aureus
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
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Polymicrobial Biofilm Inhibition Effects of Acetate-Buffered Chitosan Sponge Delivery Device.
Jennings, Jessica Amber; Beenken, Karen E; Parker, Ashley C; Smith, James Keaton; Courtney, Harry S; Smeltzer, Mark S; Haggard, Warren O
2016-04-01
Polymicrobial biofilm-associated implant infections present a challenging clinical problem. Through modifications of lyophilized chitosan sponges, degradable drug delivery devices for antibiotic solution have been fabricated for prevention and treatment of contaminated musculoskeletal wounds. Elution of amikacin, vancomycin, or a combination of both follows a burst release pattern with vancomycin released above minimum inhibitory concentration for Staphylococcus aureus for 72 h and amikacin released above inhibitory concentrations for Pseudomonas aeruginosa for 3 h. Delivery of a vancomycin, amikacin, or a combination of both reduces biofilm formation on polytetrafluoroethylene catheters in an in vivo model of contamination. Release of dual antibiotics from sponges is more effective at preventing biofilm formation than single-loaded chitosan sponges. Treatment of pre-formed biofilm with high-dose antibiotic release from chitosan sponges shows minimal reduction after 48 h. These results demonstrate infection-preventive efficacy for antibiotic-loaded sponges, as well as the need for modifications in the development of advanced materials to enhance treatment efficacy in removing established biofilm. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Zapotoczna, Marta; McCarthy, Hannah; Rudkin, Justine K; O'Gara, James P; O'Neill, Eoghan
2015-12-15
High-level resistance to antimicrobial drugs is a major factor in the pathogenesis of chronic Staphylococcus aureus biofilm-associated, medical device-related infections. Antimicrobial susceptibility analysis revealed that biofilms grown for ≤ 24 hours on biomaterials conditioned with human plasma under venous shear in iron-free cell culture medium were significantly more susceptible to antistaphylococcal antibiotics. Biofilms formed under these physiologically relevant conditions were regulated by SaeRS and dependent on coagulase-catalyzed conversion of fibrinogen into fibrin. In contrast, SarA-regulated biofilms formed on uncoated polystyrene in nutrient-rich bacteriological medium were mediated by the previously characterized biofilm factors poly-N-acetyl glucosamine, fibronectin-binding proteins, or autolytic activity and were antibiotic resistant. Coagulase-mediated biofilms exhibited increased antimicrobial resistance over time (>48 hours) but were always susceptible to dispersal by the fibrinolytic enzymes plasmin or nattokinase. Biofilms recovered from infected central venous catheters in a rat model of device-related infection were dispersed by nattokinase, supporting the important role of the biofilm phenotype and identifying a potentially new therapeutic approach with antimicrobials and fibrinolytic drugs, particularly during the early stages of device-related infection. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
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Oliveira, Adauê S; Kaizer, Marina R; Azevedo, Marina S; Ogliari, Fabrício A; Cenci, Maximiliano S; Moraes, Rafael R
2015-11-03
This study was designed to apply (super)hydrophobic crosslinked coatings by means of a sol-gel process on the surface of orthodontic devices and investigate the potential effect of these coatings in reducing the early retention of oral biofilm. Two organosilane-based hydrophobic solutions (HSs) were prepared containing hexadecyltrimethoxysilane diluted in ethanol (HS1) or 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane diluted in dimethyl sulfoxide (HS2). Stainless steel plates and ceramic discs were coated with HS1 or HS2 and heated at 150 °C for 2 h for condensation of a crosslinked SiO x network. Organosilane coatings were applied after previous, or no, surface sandblasting. Commercial stainless steel and ceramic brackets were used to evaluate oral biofilm retention after 12 h or 24 h of biofilm growth, using a microcosm model with human saliva as the inoculum. Surface roughness analysis (Ra, μm) indicated that sandblasting associated with organosilane coatings increased roughness for stainless steel brackets only. Analysis of the water contact angle showed that the stainless steel surface treated with HS1 was hydrophobic (~123°), while the ceramic surface treated with HS2 was superhydrophobic (~155°). Biofilm retention after 24 h was significantly lower in groups treated with hydrophobic coatings. An exponential reduction in biofilm accumulation was associated with increased water contact angle for both stainless steel and ceramic at 24 h. Application of (super)hydrophobic coatings on the surface of stainless steel and ceramic orthodontic devices might reduce the retention of oral biofilm.
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Said, Jawal; Walker, Michael; Parsons, David; Stapleton, Paul; Beezer, Anthony E; Gaisford, Simon
2015-04-01
Isothermal microcalorimetry (IMC) is particularly suited to the study of microbiological samples in complex or heterogeneous environments because it does not require optical clarity of the sample and can detect metabolic activity from as few as 10(4) CFU/mL cells. While the use of IMC for studying planktonic cultures is well established, in the clinical environment bacteria are most likely to be present as biofilms. Biofilm prevention and eradication present a number of challenges to designers and users of medical devices and implants, since bacteria in biofilm colonies are usually more resistant to antimicrobial agents. Analytical tools that facilitate investigation of biofilm formation are therefore extremely useful. While it is possible to study pre-prepared biofilms in closed ampoules, better correlation with in vivo behaviour can be achieved using a system in which the bacterial suspension is flowing. Here, we discuss the potential of flow microcalorimetry for studying biofilms and report the development of a simple flow system that can be housed in a microcalorimeter. The use of the flow system is demonstrated with biofilms of Staphylococcus aureus. Copyright © 2014 Elsevier Inc. All rights reserved.
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Fungal Biofilms, Drug Resistance, and Recurrent Infection
Desai, Jigar V.; Mitchell, Aaron P.; Andes, David R.
2014-01-01
A biofilm is a surface-associated microbial community. Diverse fungi are capable of biofilm growth. The significance of this growth form for infection biology is that biofilm formation on implanted devices is a major cause of recurrent infection. Biofilms also have limited drug susceptibility, making device-associated infection extremely difficult to treat. Biofilm-like growth can occur during many kinds of infection, even when an implanted device is not present. Here we summarize the current understanding of fungal biofilm formation, its genetic control, and the basis for biofilm drug resistance. PMID:25274758
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The Edmonton and Calgary aviation markets : a tale of two more cities
DOT National Transportation Integrated Search
2004-05-01
Passenger air traffic movements in Calgary and Edmonton were roughly equal in 1963 but, since : that time, the Calgary market has grown much larger than that of Edmonton. This Paper examines : a number of factors, as well as differences in the airpor...
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Soukos, Nikolaos S [Revere, MA; Lee, Shun [Arlington, VA; Doukas, Apostolos G [Belmont, MA
2008-02-19
Methods for permeabilizing biofilms using stress waves are described. The methods involve applying one or more stress waves to a biofilm, e.g., on a surface of a device or food item, or on a tissue surface in a patient, and then inducing stress waves to create transient increases in the permeability of the biofilm. The increased permeability facilitates delivery of compounds, such as antimicrobial or therapeutic agents into and through the biofilm.
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Multi-depth valved microfluidics for biofilm segmentation
NASA Astrophysics Data System (ADS)
Meyer, M. T.; Subramanian, S.; Kim, Y. W.; Ben-Yoav, H.; Gnerlich, M.; Gerasopoulos, K.; Bentley, W. E.; Ghodssi, R.
2015-09-01
Bacterial biofilms present a societal challenge, as they occur in the majority of infections but are highly resistant to both immune mechanisms and traditional antibiotics. In the pursuit of better understanding biofilm biology for developing new treatments, there is a need for streamlined, controlled platforms for biofilm growth and evaluation. We leverage advantages of microfluidics to develop a system in which biofilms are formed and sectioned, allowing parallel assays on multiple sections of one biofilm. A microfluidic testbed with multiple depth profiles was developed to accommodate biofilm growth and sectioning by hydraulically actuated valves. In realization of the platform, a novel fabrication technique was developed for creating multi-depth microfluidic molds using sequentially patterned photoresist separated and passivated by conformal coatings using atomic layer deposition. Biofilm thickness variation within three separately tested devices was less than 13% of the average thickness in each device, while variation between devices was 23% of the average thickness. In a demonstration of parallel experiments performed on one biofilm within one device, integrated valves were used to trisect the uniform biofilms with one section maintained as a control, and two sections exposed to different concentrations of sodium dodecyl sulfate. The technology presented here for multi-depth microchannel fabrication can be used to create a host of microfluidic devices with diverse architectures. While this work focuses on one application of such a device in biofilm sectioning for parallel experimentation, the tailored architectures enabled by the fabrication technology can be used to create devices that provide new biological information.
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Towards fabrication of 3D printed medical devices to prevent biofilm formation.
Sandler, Niklas; Salmela, Ida; Fallarero, Adyary; Rosling, Ari; Khajeheian, Mohammad; Kolakovic, Ruzica; Genina, Natalja; Nyman, Johan; Vuorela, Pia
2014-01-01
The use of three-dimensional (3D) printing technologies is transforming the way that materials are turned into functional devices. We demonstrate in the current study the incorporation of anti-microbial nitrofurantoin in a polymer carrier material and subsequent 3D printing of a model structure, which resulted in an inhibition of biofilm colonization. The approach taken is very promising and can open up new avenues to manufacture functional medical devices in the future. Copyright © 2013 Elsevier B.V. All rights reserved.
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Piercey, Marta J; Hingston, Patricia A; Truelstrup Hansen, Lisbeth
2016-04-16
Listeria monocytogenes is a pathogenic foodborne bacterium whose persistence in food processing environments is in part attributed to its biofilm formation. Most biofilm studies have been carried out at 30-37 °C rather than at temperatures found in the food processing plants (i.e., 10-20 °C). The objective of the present study was to mine for novel genes that contribute to L. monocytogenes biofilm formation at 15 °C using the random insertional mutagenesis approach. A library of 11,024 L. monocytogenes 568 (serotype 1/2a) Himar1 insertional mutants was created. Mutants with reduced or enhanced biofilm formation at 15 °C were detected in microtiter plate assays with crystal violet and safranin staining. Fourteen mutants expressed enhanced biofilm phenotypes, and harbored transposon insertions in genes encoding cell wall biosynthesis, motility, metabolism, stress response, and cell surface associated proteins. Deficient mutants (n=5) contained interruptions in genes related to peptidoglycan, teichoic acid, or lipoproteins. Enhanced mutants produced significantly (p<0.05) higher cell densities in biofilm formed on stainless steel (SS) coupons at 15 °C (48 h) than deficient mutants, which were also more sensitive to benzalkonium chloride. All biofilm deficient mutants and four enhanced mutants in the microtiter plate assay (flaA, cheR, lmo2563 and lmo2488) formed no biofilm in a peg lid assay (Calgary biofilm device) while insertions in lmo1224 and lmo0543 led to excess biofilm in all assays. Two enhanced biofilm formers were more resistant to enzymatic removal with DNase, proteinase K or pectinase than the parent strain. Scanning electron microscopy of individual biofilms made by five mutants and the parent on SS surfaces showed formation of heterogeneous biofilm with dense zones by immotile mutants, while deficient mutants exhibited sparse growth. In conclusion, interruptions of 9 genes not previously linked to biofilm formation in L. monocytogenes (lmo2572, lmo
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Evaluation of the French Immersion Weekends, French Centre, University of Calgary, 1979-80.
ERIC Educational Resources Information Center
Klinck, Patricia
Four French immersion weekends for continuing education students at the University of Calgary were evaluated. Each weekend involved recreational activities for twenty students and four French-speaking monitors at one of two recreational retreats near Calgary. The purpose of the program was to promote fluency in French by encouraging its use in a…
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Biofilm Formation by Cryptococcus neoformans.
Martinez, Luis R; Casadevall, Arturo
2015-06-01
The fungus Cryptococcus neoformans possesses a polysaccharide capsule and can form biofilms on medical devices. The increasing use of ventriculoperitoneal shunts to manage intracranial hypertension associated with cryptococcal meningoencephalitis highlights the importance of investigating the biofilm-forming properties of this organism. Like other microbe-forming biofilms, C. neoformans biofilms are resistant to antimicrobial agents and host defense mechanisms, causing significant morbidity and mortality. This chapter discusses the recent advances in the understanding of cryptococcal biofilms, including the role of its polysaccharide capsule in adherence, gene expression, and quorum sensing in biofilm formation. We describe novel strategies for the prevention or eradication of cryptococcal colonization of medical prosthetic devices. Finally, we provide fresh thoughts on the diverse but interesting directions of research in this field that may result in new insights into C. neoformans biology.
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Information Services at the University of Calgary.
ERIC Educational Resources Information Center
Norris, Douglas
The University of Calgary was the first university in Canada to combine its library, computer center, and audiovisual services into one unit. For a period of three years the Division of Information Services administered and coordinated library services, computer services, and communications media. The organizational structure, objectives, and the…
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NASA Astrophysics Data System (ADS)
Han, Soo; Ji, Seungmuk; Abdullah, Abdullah; Kim, Duckil; Lim, Hyuneui; Lee, Donghyun
2018-01-01
Bacterial biofilm formation on optical devices such as contact lenses, optical glasses, endoscopic devices, and microscopic slides and lenses are major concerns in the field of medicine and biomedical engineering. To solve these problems, here we present the first report of superhydrophilic transparent nanopillar-structured surfaces with bactericidal properties. To construct bactericidal surfaces, we imitated a topological mechanism found in nature in which nanopillar-structured surfaces cause a mechanical disruption of the outer cell membranes of bacteria, resulting in bacterial cell death. We used nanosphere lithography to fabricate nanopillars with various sharpnesses and heights on a quartz substrate. Water contact angle and light reflectance measurements revealed superhydrophilic, antifogging and antireflective properties, which are important for use in optical devices. To determine bactericidal efficiency, the fabricated surfaces were incubated and tested against two Gram-negative bacteria associated with biofilm formation and various diseases in humans, Pseudomonas aeruginosa and Escherichia coli. The highest bactericidal activity was achieved with nanopillars that measured 300 nm in height and 10 nm in apex diameter. Quartz substrates patterned with such nanopillars killed ∼38,000 P. aeruginosa and ∼27,000 E. coli cells cm-2 min-1, respectively. Thus, the newly designed nanopillar-structured bactericidal surfaces are suitable for use in the development of superhydrophilic and transparent optical devices.
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Ramasamy, Mohankandhasamy; Lee, Jintae
2016-01-01
Bacterial colonization in the form of biofilms on surfaces causes persistent infections and is an issue of considerable concern to healthcare providers. There is an urgent need for novel antimicrobial or antibiofilm surfaces and biomedical devices that provide protection against biofilm formation and planktonic pathogens, including antibiotic resistant strains. In this context, recent developments in the material science and engineering fields and steady progress in the nanotechnology field have created opportunities to design new biomaterials and surfaces with anti-infective, antifouling, bactericidal, and antibiofilm properties. Here we review a number of the recently developed nanotechnology-based biomaterials and explain underlying strategies used to make antibiofilm surfaces.
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2016-01-01
Bacterial colonization in the form of biofilms on surfaces causes persistent infections and is an issue of considerable concern to healthcare providers. There is an urgent need for novel antimicrobial or antibiofilm surfaces and biomedical devices that provide protection against biofilm formation and planktonic pathogens, including antibiotic resistant strains. In this context, recent developments in the material science and engineering fields and steady progress in the nanotechnology field have created opportunities to design new biomaterials and surfaces with anti-infective, antifouling, bactericidal, and antibiofilm properties. Here we review a number of the recently developed nanotechnology-based biomaterials and explain underlying strategies used to make antibiofilm surfaces. PMID:27872845
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Inhibition of Staphylococcus epidermidis Biofilm by Trimethylsilane Plasma Coating
Ma, Yibao; Jones, John E.; Ritts, Andrew C.; Yu, Qingsong
2012-01-01
Biofilm formation on implantable medical devices is a major impediment to the treatment of nosocomial infections and promotes local progressive tissue destruction. Staphylococcus epidermidis infections are the leading cause of biofilm formation on indwelling devices. Bacteria in biofilms are highly resistant to antibiotic treatment, which in combination with the increasing prevalence of antibiotic resistance among human pathogens further complicates treatment of biofilm-related device infections. We have developed a novel plasma coating technology. Trimethylsilane (TMS) was used as a monomer to coat the surfaces of 316L stainless steel and grade 5 titanium alloy, which are widely used in implantable medical devices. The results of biofilm assays demonstrated that this TMS coating markedly decreased S. epidermidis biofilm formation by inhibiting the attachment of bacterial cells to the TMS-coated surfaces during the early phase of biofilm development. We also discovered that bacterial cells on the TMS-coated surfaces were more susceptible to antibiotic treatment than their counterparts in biofilms on uncoated surfaces. These findings suggested that TMS coating could result in a surface that is resistant to biofilm development and also in a bacterial community that is more sensitive to antibiotic therapy than typical biofilms. PMID:22964248
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Sustained prevention of biofilm formation on a novel silicone matrix suitable for medical devices.
Steffensen, Søren Langer; Vestergaard, Merete Hedemark; Groenning, Minna; Alm, Martin; Franzyk, Henrik; Nielsen, Hanne Mørck
2015-08-01
Bacterial colonization and biofilm formation on medical devices constitute major challenges in clinical long-term use of e.g. catheters due to the risk of (re)infection of patients, which would result in additional use of antibiotics risking bacterial resistance development. The aim of the present project was to introduce a novel antibacterial approach involving an advanced composite material applicable for medical devices. The polymeric composites investigated consisted of a hydrogel network of cross-linked poly(2-hydroxyethyl methacrylate) (PHEMA) embedded in a poly(dimethylsiloxane) (PDMS) silicone elastomer produced using supercritical carbon dioxide (scCO2). In these materials, the hydrogel may contain an active pharmaceutical ingredient while the silicone elastomer provides the sufficient mechanical stability of the material. In these conceptual studies, the antimicrobial agent ciprofloxacin was loaded into the polymer matrix by a post-polymerization loading procedure. Sustained release of ciprofloxacin was demonstrated, and the release could be controlled by varying the hydrogel content in the range 13-38% (w/w) and by changing the concentration of ciprofloxacin during loading in the range of 1-20mg/mL. Devices containing 25% (w/w) hydrogel and loaded with ciprofloxacin displayed a strong antibacterial effect against Staphylococcus aureus bacterial colonization and subsequent biofilm formation on the device material was inhibited for 29days. In conclusion, the hydrogel/silicone composite represents a promising candidate material for medical devices that prevent bacterial colonization during long-term use. Copyright © 2015 Elsevier B.V. All rights reserved.
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Update on biofilm infections in the urinary tract.
Tenke, Peter; Köves, Béla; Nagy, Károly; Hultgren, Scott J; Mendling, Werner; Wullt, Björn; Grabe, Magnus; Wagenlehner, Florian M E; Cek, Mete; Pickard, Robert; Botto, Henry; Naber, Kurt G; Bjerklund Johansen, Truls E
2012-02-01
Biofilm infections have a major role in implants or devices placed in the human body. As part of the endourological development, a great variety of foreign bodies have been designed, and with the increasing number of biomaterial devices used in urology, biofilm formation and device infection is an issue of growing importance. A literature search was performed in the Medline database regarding biofilm formation and the role of biofilms in urogenital infections using the following items in different combinations: "biofilm," "urinary tract infection," "bacteriuria," "catheter," "stent," and "encrustation." The studies were graded using the Oxford Centre for Evidence-based Medicine classification. The authors present an update on the mechanism of biofilm formation in the urinary tract with special emphasis on the role of biofilms in lower and upper urinary tract infections, as well as on biofilm formation on foreign bodies, such as catheters, ureteral stents, stones, implants, and artificial urinary sphincters. The authors also summarize the different methods developed to prevent biofilm formation on urinary foreign bodies. Several different approaches are being investigated for preventing biofilm formation, and some promising results have been obtained. However, an ideal method has not been developed. Future researches have to aim at identifying effective mechanisms for controlling biofilm formation and to develop antimicrobial agents effective against bacteria in biofilms.
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Analysis of pharmacist-patient communication using the Calgary-Cambridge guide.
Greenhill, Nicola; Anderson, Claire; Avery, Anthony; Pilnick, Alison
2011-06-01
This study explored communication between pharmacists and patients through application of the Calgary-Cambridge guide [1] to appointment-based pharmacist-patient consultations and considers use of the guide in pharmacy education. Eighteen patients attending appointment-based consultations with five pharmacists were recruited to this qualitative study. Consultations were audio-recorded and observed. Transcripts were coded according to the use of skills within the guide and analysed thematically. The results showed good use of many skills by pharmacists, particularly signposting and closing the session. Some skills were poorly represented such as listening effectively, eliciting the patient's perspective, effective use of computers and creating patient-centred consultations. A key theme of social conversation was present in the data but this skill was not defined in the guide. The Calgary-Cambridge guide was developed for use in medical consultations but its application to pharmacist-patient consultations showed that the guide could be successfully used in pharmacy with some minor alterations. Pharmacists may need more training to improve the use of specific communication skills including how to conduct a patient-centred consultation. The Calgary-Cambridge guide is well aligned with many aspects of pharmacist-patient consultations and could help pharmacists to improve their consultation skills. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
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An optical microfluidic platform for spatiotemporal biofilm treatment monitoring
NASA Astrophysics Data System (ADS)
Kim, Young Wook; Mosteller, Matthew P.; Subramanian, Sowmya; Meyer, Mariana T.; Bentley, William E.; Ghodssi, Reza
2016-01-01
Bacterial biofilms constitute in excess of 65% of clinical microbial infections, with the antibiotic treatment of biofilm infections posing a unique challenge due to their high antibiotic tolerance. Recent studies performed in our group have demonstrated that a bioelectric effect featuring low-intensity electric signals combined with antibiotics can significantly improve the efficacy of biofilm treatment. In this work, we demonstrate the bioelectric effect using sub-micron thick planar electrodes in a microfluidic device. This is critical in efforts to develop microsystems for clinical biofilm infection management, including both in vivo and in vitro applications. Adaptation of the method to the microscale, for example, can enable the development of localized biofilm infection treatment using microfabricated medical devices, while augmenting existing capabilities to perform biofilm management beyond the clinical realm. Furthermore, due to scale-down of the system, the voltage requirement for inducing the electric field is reduced further below the media electrolysis threshold. Enhanced biofilm treatment using the bioelectric effect in the developed microfluidic device elicited a 56% greater reduction in viable cell density and 26% further decrease in biomass growth compared to traditional antibiotic therapy. This biofilm treatment efficacy, demonstrated in a micro-scale device and utilizing biocompatible voltage ranges, encourages the use of this method for future clinical biofilm treatment applications.
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Update on biofilm infections in the urinary tract
Köves, Béla; Nagy, Károly; Hultgren, Scott J.; Mendling, Werner; Wullt, Björn; Grabe, Magnus; Wagenlehner, Florian M. E.; Cek, Mete; Pickard, Robert; Botto, Henry; Naber, Kurt G.; Bjerklund Johansen, Truls E.
2015-01-01
Purpose Biofilm infections have a major role in implants or devices placed in the human body. As part of the endourological development, a great variety of foreign bodies have been designed, and with the increasing number of biomaterial devices used in urology, biofilm formation and device infection is an issue of growing importance. Methods A literature search was performed in the Medline database regarding biofilm formation and the role of biofilms in urogenital infections using the following items in different combinations: “biofilm,” “urinary tract infection,” “bacteriuria,” “catheter,” “stent,” and “encrustation.” The studies were graded using the Oxford Centre for Evidence-based Medicine classification. Results The authors present an update on the mechanism of biofilm formation in the urinary tract with special emphasis on the role of biofilms in lower and upper urinary tract infections, as well as on biofilm formation on foreign bodies, such as catheters, ureteral stents, stones, implants, and artificial urinary sphincters. The authors also summarize the different methods developed to prevent biofilm formation on urinary foreign bodies. Conclusions Several different approaches are being investigated for preventing biofilm formation, and some promising results have been obtained. However, an ideal method has not been developed. Future researches have to aim at identifying effective mechanisms for controlling biofilm formation and to develop antimicrobial agents effective against bacteria in biofilms. PMID:21590469
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A novel planar flow cell for studies of biofilm heterogeneity and flow-biofilm interactions
Zhang, Wei; Sileika, Tadas S.; Chen, Cheng; Liu, Yang; Lee, Jisun; Packman, Aaron I.
2012-01-01
Biofilms are microbial communities growing on surfaces, and are ubiquitous in nature, in bioreactors, and in human infection. Coupling between physical, chemical, and biological processes is known to regulate the development of biofilms; however, current experimental systems do not provide sufficient control of environmental conditions to enable detailed investigations of these complex interactions. We developed a novel planar flow cell that supports biofilm growth under complex two-dimensional fluid flow conditions. This device provides precise control of flow conditions and can be used to create well-defined physical and chemical gradients that significantly affect biofilm heterogeneity. Moreover, the top and bottom of the flow chamber are transparent, so biofilm growth and flow conditions are fully observable using non-invasive confocal microscopy and high-resolution video imaging. To demonstrate the capability of the device, we observed the growth of Pseudomonas aeruginosa biofilms under imposed flow gradients. We found a positive relationship between patterns of fluid velocity and biofilm biomass because of faster microbial growth under conditions of greater local nutrient influx, but this relationship eventually reversed because high hydrodynamic shear leads to the detachment of cells from the surface. These results reveal that flow gradients play a critical role in the development of biofilm communities. By providing new capability for observing biofilm growth, solute and particle transport, and net chemical transformations under user-specified environmental gradients, this new planar flow cell system has broad utility for studies of environmental biotechnology and basic biofilm microbiology, as well as applications in bioreactor design, environmental engineering, biogeochemistry, geomicrobiology, and biomedical research. PMID:21656713
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Chan, Cynthia; Hardin, Thomas C; Smart, Jennifer I
2015-01-01
Tissue- and device-associated biofilm infections are important medical problems. These infections are difficult to treat due to a high-level of tolerance to antibiotics. Telavancin has been studied in several in vitro biofilm models and has demonstrated efficacy against staphylococcal and enterococcal-associated biofilm infections, including those formed by methicillin-resistant Staphylococcus aureus. Telavancin was effective against the difficult-to-treat vancomycin- and glycopeptide-intermediate strains of S. aureus in these models. Furthermore, the efficacy of telavancin has been evaluated in several biofilm-related in vivo models, including osteomyelitis, endocarditis and device-associated infections in rabbits. Overall, telavancin exhibited similar or greater efficacy than vancomycin and other comparators in these animal models and maintained activity against vancomycin-intermediate and daptomycin nonsusceptible strains of S. aureus.
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Fungal Biofilms: In vivo models for discovery of anti-biofilm drugs
Nett, Jeniel E.; Andes, David
2015-01-01
SUMMARY During infection, fungi frequently transition to a biofilm lifestyle, proliferating as communities of surface-adherent aggregates of cells. Phenotypically, cells in a biofilm are distinct from free-floating cells. Their high tolerance of antifungals and ability to withstand host defenses are two characteristics that foster resilience. Biofilm infections are particularly difficult to eradicate and most available antifungals have minimal activity. Therefore, the discovery of novel compounds and innovative strategies to treat fungal biofilms is of great interest. Although many fungi have been observed to form biofilms, the most well-studied is Candida albicans. Animal models have been developed to simulate common Candida device-associated infections, including those involving vascular catheters, dentures, urinary catheters, and subcutaneous implants. Models have also reproduced the most common mucosal biofilm infections, oropharyngeal and vaginal candidiasis. These models incorporate the anatomical site, immune components, and fluid dynamics of clinical niches and have been instrumental in the study of drug resistance and investigation of novel therapies. This chapter describes the significance of fungal biofilm infections, the animal models developed for biofilm study, and how these models have contributed to development of new strategies for eradication of fungal biofilm infections. PMID:26397003
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Fungal Biofilms: In Vivo Models for Discovery of Anti-Biofilm Drugs.
Nett, Jeniel E; Andes, David R
2015-06-01
During infection, fungi frequently transition to a biofilm lifestyle, proliferating as communities of surface-adherent aggregates of cells. Phenotypically, cells in a biofilm are distinct from free-floating cells. Their high tolerance of antifungals and ability to withstand host defenses are two characteristics that foster resilience. Biofilm infections are particularly difficult to eradicate, and most available antifungals have minimal activity. Therefore, the discovery of novel compounds and innovative strategies to treat fungal biofilms is of great interest. Although many fungi have been observed to form biofilms, the most well-studied is Candida albicans. Animal models have been developed to simulate common Candida device-associated infections, including those involving vascular catheters, dentures, urinary catheters, and subcutaneous implants. Models have also reproduced the most common mucosal biofilm infections: oropharyngeal and vaginal candidiasis. These models incorporate the anatomical site, immune components, and fluid dynamics of clinical niches and have been instrumental in the study of drug resistance and investigation of novel therapies. This chapter describes the significance of fungal biofilm infections, the animal models developed for biofilm study, and how these models have contributed to the development of new strategies for the eradication of fungal biofilm infections.
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[Candida biofilm-related infections].
Del Pozo, José Luis; Cantón, Emilia
2016-01-01
The number of biomedical devices (intravascular catheters, heart valves, joint replacements, etc.) that are implanted in our hospitals has increased exponentially in recent years. Candida species are pathogens which are becoming more significant in these kinds of infections. Candida has two forms of development: planktonic and in biofilms. A biofilm is a community of microorganisms which adhere to a surface and are enclosed by an extracellular matrix. This form of development confers a high resistance to the antimicrobial agents. This is the reason why antibiotic treatments usually fail and biomedical devices may have to be removed in most cases. Unspecific adhesion mechanisms, the adhesion-receptor systems, and an intercellular communication system called quorum sensing play an essential role in the development of Candida biofilms. In general, the azoles have poor activity against Candida biofilms, while echinocandins and polyenes show a greater activity. New therapeutic strategies need to be developed due to the high morbidity and mortality and high economic costs associated with these infections. Most studies to date have focused on bacterial biofilms. The knowledge of the formation of Candida biofilms and their composition is essential to develop new preventive and therapeutic strategies. Copyright © 2014 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.
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Taylor, Patrick K; Yeung, Amy T Y; Hancock, Robert E W
2014-12-10
The growth of bacteria as structured aggregates termed biofilms leads to their protection from harsh environmental conditions such as physical and chemical stresses, shearing forces, and limited nutrient availability. Because of this highly adapted ability to survive adverse environmental conditions, bacterial biofilms are recalcitrant to antibiotic therapies and immune clearance. This is particularly problematic in hospital settings where biofilms are a frequent cause of chronic and device-related infections and constitute a significant burden on the health-care system. The major therapeutic strategy against infections is the use of antibiotics, which, due to adaptive resistance, are often insufficient to clear biofilm infections. Thus, novel biofilm-specific therapies are required. Specific features of biofilm development, such as surface adherence, extracellular matrix formation, quorum sensing, and highly regulated biofilm maturation and dispersal are currently being studied as targets to be exploited in the development of novel biofilm-specific treatments. Using Pseudomonas aeruginosa for illustrative purposes, this review highlights the antibiotic resistance mechanisms of biofilms, and discusses current research into novel biofilm-specific therapies. Copyright © 2014 Elsevier B.V. All rights reserved.
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Static biofilm removal around ultrasonic tips in vitro.
Thurnheer, Thomas; Rohrer, Elodie; Belibasakis, Georgios N; Attin, Thomas; Schmidlin, Patrick R
2014-09-01
This study aims to investigate the biofilm removal capacity of two ultrasonic tips under standardized conditions using a multi-species biofilm model. Six-species biofilms were grown on hydroxyapatite discs for 64.5 h and were treated for 15 s with a standardized load of 40 g with a piezoelectric or magnetostrictive device. Tips were applied either with the tip end or with the side facing downwards. Detached bacteria were determined in the supernatant and colony-forming units (CFUs) counted after 72 h of incubation. Untreated specimens served as controls. Moreover, the biofilms remaining on the hydroxyapatite surface after treatment were stained using the Live/Dead stain, and the pattern of their detachment was assessed by confocal laser scanning microscopy (CLSM). As compared to the untreated control, it was found that only a side application of the magnetostrictive device was able to remove efficiently the biofilm. In contrast, its tip application as well as both applications of the piezoelectric device removed significantly less bacteria from the biofilm structure. These findings were corroborated by CLSM observation. Both ultrasonic tips under investigations led to bacterial detachment, but the action mode as well as the tip configuration and adaptation appeared to be influenced by the biofilm removal effectiveness. Biofilm removal remains a main goal of ultrasonic debridement. This should be reflected in respective laboratory investigations. The presented combination of methods applied on a multi-species biofilm model in vitro allows the evaluation of the effectiveness of different ultrasonic scaler applications.
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Biofilms in Infections of the Eye
Bispo, Paulo J. M.; Haas, Wolfgang; Gilmore, Michael S.
2015-01-01
The ability to form biofilms in a variety of environments is a common trait of bacteria, and may represent one of the earliest defenses against predation. Biofilms are multicellular communities usually held together by a polymeric matrix, ranging from capsular material to cell lysate. In a structure that imposes diffusion limits, environmental microgradients arise to which individual bacteria adapt their physiologies, resulting in the gamut of physiological diversity. Additionally, the proximity of cells within the biofilm creates the opportunity for coordinated behaviors through cell–cell communication using diffusible signals, the most well documented being quorum sensing. Biofilms form on abiotic or biotic surfaces, and because of that are associated with a large proportion of human infections. Biofilm formation imposes a limitation on the uses and design of ocular devices, such as intraocular lenses, posterior contact lenses, scleral buckles, conjunctival plugs, lacrimal intubation devices and orbital implants. In the absence of abiotic materials, biofilms have been observed on the capsule, and in the corneal stroma. As the evidence for the involvement of microbial biofilms in many ocular infections has become compelling, developing new strategies to prevent their formation or to eradicate them at the site of infection, has become a priority. PMID:25806622
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Embedded biofilm, a new biofilm model based on the embedded growth of bacteria.
Jung, Yong-Gyun; Choi, Jungil; Kim, Soo-Kyoung; Lee, Joon-Hee; Kwon, Sunghoon
2015-01-01
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. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
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El-Azizi, Mohamed; Farag, Noha; Khardori, Nancy
2015-04-03
Candida albicans is a common cause of a variety of superficial and invasive disseminated infections the majority of which are associated with biofilm growth on implanted devices. The aim of the study is to evaluate the activity of amphotericin B and voriconazole against the biofilm and the biofilm-dispersed cells of Candida albicans using a newly developed in vitro pharmacokinetic model which simulates the clinical situation when the antifungal agents are administered intermittently. RPMI medium containing 1-5 X 10(6) CFU/ml of C. albicans was continuously delivered to the device at 30 ml/h for 2 hours. The planktonic cells were removed and biofilms on the catheter were kept under continuous flow of RPMI medium at 10 ml/h. Five doses of amphotericin B or voriconazole were delivered to 2, 5 and 10 day-old biofilms at initial concentrations (2 and 3 μg/ml respectively) that were exponentially diluted. Dispersed cells in effluents from the device were counted and the adherent cells on the catheter were evaluated after 48 h of the last dose. The minimum inhibitory concentration of voriconazole and amphotericin B against the tested isolate was 0.0325 and 0.25 μg/ml respectively. Amphotericin B significantly reduced the dispersion of C. albicans cells from the biofilm. The log10 reduction in the dispersed cells was 2.54-3.54, 2.30-3.55, and 1.94-2.50 following addition of 5 doses of amphotericin B to 2-, 5- and 10-day old biofilms respectively. The number of the viable cells within the biofilm was reduced by 18 (±7.63), 5 and 4% following addition of the 5 doses of amphotericin B to the biofilms respectively. Voriconazole showed no significant effect on the viability of C. albicans within the biofilm. Both antifungal agents failed to eradicate C. albicans biofilm or stop cell dispersion from them and the resistance progressed with maturation of the biofilm. These findings go along with the need for removal of devices in spite of antifungal therapy in patients
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Centralization of a regional clinical microbiology service: The Calgary experience
Church, Deirdre L; Hall, Paula
1999-01-01
Diagnostic laboratory services in Alberta have been dramatically restructured over the past five years. In 1994, Alberta Health embarked on an aggressive laboratory restructuring that cut back approximately 30% of the overall monies previously paid to the laboratory service sector in Calgary. A unique service delivery model consolidated all institutional and community-based diagnostic testing in a company called Calgary Laboratory Services (CLS) in late 1996. CLS was formed by a public/private partnership between the Calgary Regional Health Care Authority (CRHA) and MDS-Kasper Laboratories. By virtue of its customer service base and scope of testing, CLS provides comprehensive regional laboratory services to the entire populace. Regional microbiology services within CLS have been successfully consolidated over the past three years into a centralized high volume laboratory (HVL). Because the HVL is not located in a hospital, rapid response laboratories (RRLs) are operated at each acute care site. Although the initial principle behind the proposed test menus for the RRLs was that only procedures requiring a clinical turnaround time of more than 2 h stay on-site, many other principles had to be used to develop and implement an efficient and clinically relevant RRL model for microbiology. From these guiding principles, a detailed assessment of the needs of each institution and extensive networking with user groups, the functions of the microbiology RRLs were established and a detailed implementation plan drawn up. The experience at CLS with regards to restructuring a regional microbiology service is described herein. A post-hoc analysis provides the pros and cons of directing and operating a regionalized microbiology service. PMID:22346397
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Enzymatic Detachment of Staphylococcus epidermidis Biofilms
Kaplan, Jeffrey B.; Ragunath, Chandran; Velliyagounder, Kabilan; Fine, Daniel H.; Ramasubbu, Narayanan
2004-01-01
The gram-positive bacterium Staphylococcus epidermidis is the most common cause of infections associated with catheters and other indwelling medical devices. S. epidermidis produces an extracellular slime that enables it to form adherent biofilms on plastic surfaces. We found that a biofilm-releasing enzyme produced by the gram-negative periodontal pathogen Actinobacillus actinomycetemcomitans rapidly and efficiently removed S. epidermidis biofilms from plastic surfaces. The enzyme worked by releasing extracellular slime from S. epidermidis cells. Precoating surfaces with the enzyme prevented S. epidermidis biofilm formation. Our findings demonstrate that biofilm-releasing enzymes can exhibit broad-spectrum activity and that these enzymes may be useful as antibiofilm agents. PMID:15215120
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Bacterial adherence and biofilm formation on medical implants: a review.
Veerachamy, Suganthan; Yarlagadda, Tejasri; Manivasagam, Geetha; Yarlagadda, Prasad Kdv
2014-10-01
Biofilms are a complex group of microbial cells that adhere to the exopolysaccharide matrix present on the surface of medical devices. Biofilm-associated infections in the medical devices pose a serious problem to the public health and adversely affect the function of the device. Medical implants used in oral and orthopedic surgery are fabricated using alloys such as stainless steel and titanium. The biological behavior, such as osseointegration and its antibacterial activity, essentially depends on both the chemical composition and the morphology of the surface of the device. Surface treatment of medical implants by various physical and chemical techniques are attempted in order to improve their surface properties so as to facilitate bio-integration and prevent bacterial adhesion. The potential source of infection of the surrounding tissue and antimicrobial strategies are from bacteria adherent to or in a biofilm on the implant which should prevent both biofilm formation and tissue colonization. This article provides an overview of bacterial biofilm formation and methods adopted for the inhibition of bacterial adhesion on medical implants. © IMechE 2014.
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Sub-Optimal Treatment of Bacterial Biofilms
Song, Tianyan; Duperthuy, Marylise; Wai, Sun Nyunt
2016-01-01
Bacterial biofilm is an emerging clinical problem recognized in the treatment of infectious diseases within the last two decades. The appearance of microbial biofilm in clinical settings is steadily increasing due to several reasons including the increased use of quality of life-improving artificial devices. In contrast to infections caused by planktonic bacteria that respond relatively well to standard antibiotic therapy, biofilm-forming bacteria tend to cause chronic infections whereby infections persist despite seemingly adequate antibiotic therapy. This review briefly describes the responses of biofilm matrix components and biofilm-associated bacteria towards sub-lethal concentrations of antimicrobial agents, which may include the generation of genetic and phenotypic variabilities. Clinical implications of bacterial biofilms in relation to antibiotic treatments are also discussed. PMID:27338489
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Candida Biofilms: Development, Architecture, and Resistance
CHANDRA, JYOTSNA; MUKHERJEE, PRANAB K.
2015-01-01
Intravascular device–related infections are often associated with biofilms (microbial communities encased within a polysaccharide-rich extracellular matrix) formed by pathogens on the surfaces of these devices. Candida species are the most common fungi isolated from catheter-, denture-, and voice prosthesis–associated infections and also are commonly isolated from contact lens–related infections (e.g., fungal keratitis). These biofilms exhibit decreased susceptibility to most antimicrobial agents, which contributes to the persistence of infection. Recent technological advances have facilitated the development of novel approaches to investigate the formation of biofilms and identify specific markers for biofilms. These studies have provided extensive knowledge of the effect of different variables, including growth time, nutrients, and physiological conditions, on biofilm formation, morphology, and architecture. In this article, we will focus on fungal biofilms (mainly Candida biofilms) and provide an update on the development, architecture, and resistance mechanisms of biofilms. PMID:26350306
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Risk factors for injuries in competitive Irish dancers enrolled in dance schools in Calgary, Canada.
Eustergerling, Mercedes; Emery, Carolyn
2015-03-01
Irish dancing has become a popular activity following international exposure to touring dance companies. Previous studies have reported high injury incidence rates in dancers. The objective of this study was to examine risk factors for injuries in competitive Irish dancers in Calgary, Canada. This is a cross-sectional study. Competitive dancers over 12 years of age in Calgary, Canada, were eligible to participate. A pen-and-paper survey was administered to gather information on demographics, risk factors for injury, and injuries in the past year. Potential risk factors included age, competitive level, participation in other physical activities, years of participation in Irish dance, and performing a warm-up or cool-down. Incidence proportions (IP) and odds ratios (OR) were estimated. Three of the five accredited dance schools in Calgary participated and a total of 36 questionnaires were completed. Twenty-six dancers (IP=72.2%; 95% CI 54.8-85.8%) reported at least one Irish dance-related injury in the past year. There were 60 injuries reported and the majority (57%) were foot or ankle injuries. Elite level dancers (OR= 6.33; CI 1.27-31.57) and dancers over 18 years of age (OR= 24.43; CI 2.60-229.56) were at greater risk of injury in the past year than non-elite and younger dancers. Elite dancers and dancers over 18 years of age are at the greatest risk of injury in Irish dance in Calgary, Canada.
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Bioelectric effect and bacterial biofilms. A systematic review
DEL POZO, J. L.; ROUSE, M. S.; PATEL, R.
2014-01-01
Bacteria growing in biofilms cause a wide range of human infections. Biofilm bacteria are resistant to antimicrobics at levels 500 to 5,000 times higher than those needed to kill non-biofilm bacteria. In vitro experiments have shown that electric current can enhance the activity of some antimicrobial agents against certain bacteria in biofilms; this has been termed the “bioelectric effect”. Direct electrical current has already been safely used in humans for fracture healing. Application of direct electric current with antimicrobial chemotherapy in humans could theoretically abrogate the need to remove the device in device-related infections, a procedure associated with substantial morbidity and cost. In this article, we review what has been described in the literature with regards to the bioelectric effect. PMID:18924090
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Mechanisms of Candida biofilm drug resistance
Taff, Heather T; Mitchell, Kaitlin F; Edward, Jessica A; Andes, David R
2013-01-01
Candida commonly adheres to implanted medical devices, growing as a resilient biofilm capable of withstanding extraordinarily high antifungal concentrations. As currently available antifungals have minimal activity against biofilms, new drugs to treat these recalcitrant infections are urgently needed. Recent investigations have begun to shed light on the mechanisms behind the profound resistance associated with the biofilm mode of growth. This resistance appears to be multifactorial, involving both mechanisms similar to conventional, planktonic antifungal resistance, such as increased efflux pump activity, as well as mechanisms specific to the biofilm lifestyle. A unique biofilm property is the production of an extracellular matrix. Two components of this material, β-glucan and extracellular DNA, promote biofilm resistance to multiple antifungals. Biofilm formation also engages several stress response pathways that impair the activity of azole drugs. Resistance within a biofilm is often heterogeneous, with the development of a subpopulation of resistant persister cells. In this article we review the molecular mechanisms underlying Candida biofilm antifungal resistance and their relative contributions during various growth phases. PMID:24059922
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Innovative strategies to overcome biofilm resistance.
Taraszkiewicz, Aleksandra; Fila, Grzegorz; Grinholc, Mariusz; Nakonieczna, Joanna
2013-01-01
We review the recent literature concerning the efficiency of antimicrobial photodynamic inactivation toward various microbial species in planktonic and biofilm cultures. The review is mainly focused on biofilm-growing microrganisms because this form of growth poses a threat to chronically infected or immunocompromised patients and is difficult to eradicate from medical devices. We discuss the biofilm formation process and mechanisms of its increased resistance to various antimicrobials. We present, based on data in the literature, strategies for overcoming the problem of biofilm resistance. Factors that have potential for use in increasing the efficiency of the killing of biofilm-forming bacteria include plant extracts, enzymes that disturb the biofilm structure, and other nonenzymatic molecules. We propose combining antimicrobial photodynamic therapy with various antimicrobial and antibiofilm approaches to obtain a synergistic effect to permit efficient microbial growth control at low photosensitizer doses.
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The ``Swiss cheese'' instability of bacterial biofilms
NASA Astrophysics Data System (ADS)
Jang, Hongchul; Rusconi, Roberto; Stocker, Roman
2012-11-01
Bacteria often adhere to surfaces, where they develop polymer-encased communities (biofilms) that display dramatic resistance to antibiotic treatment. A better understanding of cell detachment from biofilms may lead to novel strategies for biofilm disruption. Here we describe a new detachment mode, whereby a biofilm develops a nearly regular array of ~50-100 μm holes. Using surface-treated microfluidic devices, we create biofilms of controlled shape and size. After the passage of an air plug, the break-up of the residual thin liquid film scrapes and rearranges bacteria on the surface, such that a ``Swiss cheese'' pattern is left in the residual biofilm. Fluorescent staining of the polymeric matrix (EPS) reveals that resistance to cell dislodgement correlates with local biofilm age, early settlers having had more time to hunker down. Because few survivors suffice to regrow a biofilm, these results point at the importance of considering microscale heterogeneity in assessing the effectiveness of biofilm removal strategies.
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Biofilm formation by Staphylococcus haemolyticus.
Fredheim, Elizabeth Gladys Aarag; Klingenberg, Claus; Rohde, Holger; Frankenberger, Stephanie; Gaustad, Peter; Flaegstad, Trond; Sollid, Johanna Ericson
2009-04-01
Infections due to coagulase-negative staphylococci (CoNS) most frequently occur after the implantation of medical devices and are attributed to the biofilm-forming potential of CoNS. Staphylococcus haemolyticus is the second most frequently isolated CoNS from patients with hospital-acquired infections. There is only limited knowledge of the nature of S. haemolyticus biofilms. The aim of this study was to characterize S. haemolyticus biofilm formation. We analyzed the biofilm-forming capacities of 72 clinical S. haemolyticus isolates. A detachment assay with NaIO(4), proteinase K, or DNase was used to determine the main biofilm components. Biofilm-associated genes, including the ica operon, were analyzed by PCR, and the gene products were sequenced. Confocal laser scanning microscopy (CLSM) was used to elucidate the biofilm structure. Fifty-three isolates (74%) produced biofilms after growth in Trypticase soy broth (TSB) with glucose, but only 22 (31%) produced biofilms after growth in TSB with NaCl. It was necessary to dissolve the biofilm in ethanol-acetone to measure the optical density of the full biofilm mass. DNase, proteinase K, and NaIO(4) caused biofilm detachment for 100%, 98%, and 38% of the isolates, respectively. icaRADBC and polysaccharide intercellular adhesin (PIA) production were found in only two isolates. CLSM indicated that the biofilm structure of S. haemolyticus clearly differs from that of S. epidermidis. We conclude that biofilm formation is a common phenotype in clinical S. haemolyticus isolates. In contrast to S. epidermidis, proteins and extracellular DNA are of functional relevance for biofilm accumulation, whereas PIA plays only a minor role. The induction of biofilm formation and determination of the biofilm mass also needed to be optimized for S. haemolyticus.
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Induced abortion and contraception use: among immigrant and Canadian-born women in Calgary, Alta.
Prey, Beatrice du; Talavlikar, Rachel; Mangat, Rupinder; Freiheit, Elizabeth A; Drummond, Neil
2014-09-01
To determine what proportion of women seeking induced abortion in the Calgary census metropolitan area were immigrants. For 2 months, eligible women were asked to complete a questionnaire. Women who refused were asked to provide their country of birth (COB) to assess for selection bias. Two abortion clinics in Calgary, Alta. Women presenting at or less than 15 weeks' gestational age for induced abortion for maternal indications. The primary outcome was the proportion of women seeking induced abortion services who were immigrants. Secondary outcomes compared socioeconomic characteristics and contraception use between immigrant and Canadian-born women. A total of 752 women either completed a questionnaire (78.6%) or provided their COB (21.4%). Overall, 28.9% of women living in the Calgary census metropolitan area who completed the questionnaire were immigrants, less than the 31.2% background proportion of immigrant women of childbearing age. However, 46.0% of women who provided only COB were immigrants. When these data were combined, 34.2% of women presenting for induced abortion identified as immigrant, a proportion not significantly different from the background proportion (P = .127). Immigrant women presenting for induced abortion tended to be older, more educated, married with children, and have increased parity. They were similar to Canadian-born women in number of previous abortions, income status, and employment status. This study suggests that immigrant women in Calgary are not presenting for induced abortion in disproportionately higher numbers, which differs from existing European literature. This is likely owing to differing socioeconomic characteristics among the immigrant women in our study from what have been previously described in the literature (typically lower socioeconomic status). Much still needs to be explored with regard to factors influencing the use of abortion services by immigrant women. Copyright© the College of Family Physicians of
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Robinson, Colin
2011-09-01
Bacterial biofilms in the mouth are prime mediators of the destruction of the dental and oral tissues. This brief review summarises recent work using a device for generating intact plaque in the mouth on natural enamel surfaces such that quantitative studies of mass transfer through natural plaque biofilms could be carried out in relation to plaque architecture. This data is discussed against the background of existing information. The device revealed complex plaque architecture with high a surface area to mass ratio decreasing from the exterior of the biofilm towards the tissue surface. Fluoride, a potent inhibitor of caries was concentrated in the outer regions of the biofilm. This implies some restriction of diffusion and possibly binding to the high surface area of the outer biofilm. Whilst all components examined conformed to this distribution pattern, some relatively uncharged materials penetrated the bacterial biomass whilst other, more highly charged materials tended to be restricted to the channels or biomass surface. Plaque architecture was robust but could be altered using detergent indicating that biomass architecture and chemistry could be manipulated as a possible means of facilitating mass transport of therapeutics. Copyright © 2011 Elsevier Ltd. All rights reserved.
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Shanmughapriya, Santhanam; Sornakumari, Haridevvenkatesan; Lency, Arumugam; Kavitha, Senthil; Natarajaseenivasan, Kalimuthusamy
2014-11-01
The presence of intrauterine contraceptive devices (IUDs) provides a solid surface for attachment of microorganisms and an ideal niche for the biofilm to form and flourish. Vaginal candidiasis is often associated with the use of IUDs. Treatment of vaginal candidiasis that develops in connection with IUD use requires their immediate removal. Here, we present in vitro evidence to support the use of combination therapy to inhibit Candida biofilm. Twenty-three clinical Candida isolates (10 C. krusei and 13 C. tropicalis) recovered from endocervical swabs obtained from IUD and non-IUD users were assessed for biofilm-formation ability. The rate of isolation of Candida did not differ significantly among IUD and non-IUD users (P = 0.183), but the biofilm-formation ability of isolates differed significantly (P = 0.02). An in vitro biofilm model with the obtained isolates was subjected to treatment with amphotericin B, tyrosol, and a combination of amphotericin B and tyrosol. Inhibition of biofilm by amphotericin B or tyrosol was found to be concentration dependent, with 50% reduction (P < 0.05) at 4 mg/l and 80 μM, respectively. Hence, a combination effect of tyrosol and amphotericin B was studied. Interestingly, approximately 90% reduction in biofilm was observed with use of 80 μM tyrosol combined with 4 mg/l amphotericin B (P < 0.001). This represents a first step in establishing an appropriate antibiofilm therapy when yeasts are present. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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NASA Astrophysics Data System (ADS)
Ge, C.; Stenhouse, K. J.; Du, K.; Xing, Z.; Norman, A. L.
2016-12-01
Carbonaceous matter is often the dominant contributor to Particulate Matter (PM) which has a significant influence on climate, air quality and human health. The measurement of particulate carbon in rainfall in Calgary, Alberta has not been studied. This study reports the sulfate and the first concentrations of particulate carbon (PC) in rainfall in Calgary. It traces seasonal carbonaceous sources for the purpose of understanding sources for air quality control. Precipitation samples are collected twice a day at the University of Calgary. Thermo-optical methods are used to analyze concentrations of PC, including elemental carbon (EC), primary organic carbon (POC) and secondary organic carbon (SOC). Sulfate concentrations are measured using ion chromatography. In this study, sources from long range transport and local emissions are examined. We emphasized the apportionment of OC/EC in oil and gas emissions and diurnal variations in transportation emissions. Weekly average data for dry deposition were calculated to estimate the scavenging ratio of EC/POC/SOC and ions in precipitation. The results of this study will be presented with an emphasis on the relationship of carbonaceous material and sulfate. A range of apportionment methods have been applied to examine limitations in quantifying SOC in fall.
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The Staphylococcal Biofilm: Adhesins, regulation, and host response
Paharik, Alexandra E.; Horswill, Alexander R.
2015-01-01
The Staphylococci comprise a diverse genus of Gram-positive, non-motile commensal organisms that inhabit the skin and mucous membranes of humans and other mammals. In general, Staphylococci are benign members of the natural flora, but many species have the capacity to be opportunistic pathogens, mainly infecting individuals who have medical device implants or are otherwise immunocompromised. S. aureus and S. epidermidis are a major source of hospital-acquired infections and are the most common causes of surgical site infections and central line-associated bloodstream infections. The ability of Staphylococci to form biofilms in vivo makes them highly resistant to chemotherapeutics and leads to chronic diseases. These biofilm infections include osteomyelitis, endocarditis, medical device implants, and persistence in the cystic fibrosis lung. Here, we provide a comprehensive analysis of our current understanding of Staphylococcal biofilm formation, with an emphasis on adhesins and regulation, while also addressing how Staphylococcal biofilms interact with the immune system. On the whole, this review will provide a thorough picture of biofilm formation of the Staphylococcus genus and how this mode of growth impacts the host. PMID:27227309
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An overview on the reactors to study drinking water biofilms.
Gomes, I B; Simões, M; Simões, L C
2014-10-01
The development of biofilms in drinking water distribution systems (DWDS) can cause pipe degradation, changes in the water organoleptic properties but the main problem is related to the public health. Biofilms are the main responsible for the microbial presence in drinking water (DW) and can be reservoirs for pathogens. Therefore, the understanding of the mechanisms underlying biofilm formation and behavior is of utmost importance in order to create effective control strategies. As the study of biofilms in real DWDS is difficult, several devices have been developed. These devices allow biofilm formation under controlled conditions of physical (flow velocity, shear stress, temperature, type of pipe material, etc), chemical (type and amount of nutrients, type of disinfectant and residuals, organic and inorganic particles, ions, etc) and biological (composition of microbial community - type of microorganism and characteristics) parameters, ensuring that the operational conditions are similar as possible to the DWDS conditions in order to achieve results that can be applied to the real scenarios. The devices used in DW biofilm studies can be divided essentially in two groups, those usually applied in situ and the bench top laboratorial reactors. The selection of a device should be obviously in accordance with the aim of the study and its advantages and limitations should be evaluated to obtain reproducible results that can be transposed into the reality of the DWDS. The aim of this review is to provide an overview on the main reactors used in DW biofilm studies, describing their characteristics and applications, taking into account their main advantages and limitations. Copyright © 2014 Elsevier Ltd. All rights reserved.
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A new method to measure and model dynamic oxygen microdistributions in moving biofilms.
Wang, Jian-Hui; Chen, You-Peng; Dong, Yang; Wang, Xi-Xi; Guo, Jin-Song; Shen, Yu; Yan, Peng; Ma, Teng-Fei; Sun, Xiu-Qian; Fang, Fang; Wang, Jing
2017-10-01
Biofilms in natural environments offer a superior solution to mitigate water pollution. Artificially intensified biofilm reactors represented by rotating biological contactors (RBCs) are widely applied and studied. Understanding the oxygen transfer process in biofilms is an important aspect of these studies, and describing this process in moving biofilms (such as biofilms in RBCs) is a particular challenge. Oxygen transfer in RBCs behaves differently than in other biological reactors due to the special oxygen supply mode that results from alternate exposure of the biofilm to wastewater and air. The study of oxygen transfer in biofilms is indispensable for understanding biodegradation in RBCs. However, the mechanisms are still not well known due to a lack of effective tools to dynamically analyze oxygen diffusion, reaction, and microdistribution in biofilms. A new experimental device, the Oxygen Transfer Modeling Device (OTMD), was designed and manufactured for this purpose, and a mathematical model was developed to model oxygen transfer in biofilm produced by an RBC. This device allowed the simulation of the local environment around the biofilm during normal RBC operation, and oxygen concentrations varying with time and depth in biofilm were measured using an oxygen microelectrode. The experimental data conformed well to the model description, indicating that the OTMD and the model were stable and reliable. Moreover, the OTMD offered a flexible approach to study the impact of a single-factor on oxygen transfer in moving biofilms. In situ environment of biofilm in an RBC was simulated, and dynamic oxygen microdistributions in the biofilm were measured and well fitted to the built model description. Copyright © 2017 Elsevier Ltd. All rights reserved.
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A regional centralized microbiology service in Calgary for the rapid diagnosis of malaria.
Church, Deirdre L; Lichtenfeld, Angelika; Elsayed, Sameer; Kuhn, Susan; Gregson, Daniel B
2003-06-01
A regional centralized laboratory service for the rapid diagnosis of malaria was implemented 3 years ago in May 1999 within the Division of Microbiology, Calgary Laboratory Services. To describe the design and performance of this unique microbiology laboratory service. Blood specimens must arrive at the central laboratory within 2 hours of collection. Thin blood smears are read and reported from suspected acute cases within 1 hour of receipt, 24 hours per day, 7 days a week, by trained and experienced microbiology technologists. All positive malaria smears are reviewed by a medical microbiologist and confirmed by polymerase chain reaction at a reference laboratory. Calgary Laboratory Services provides integrated laboratory services to the Calgary Health Region, an urban area of more than 1 million people. Performance of the service has been continuously monitored by measuring preanalytic and analytic test turnaround times, test accuracy, clinical relevance, and the results of proficiency testing. More than 90% of blood specimens for malaria from community locations have consistently arrived within 2 hours of collection, and hospitals have reached this target within the past year. Although polymerase chain reaction was more sensitive at detecting the presence of malaria, the expert microscopists were as accurate at determining the type of Plasmodium infection. More than 95% of all positive smear results are consistently reported within 2 hours of receipt of a blood specimen. Implementation of a regional centralized microbiology service has improved our ability to make a rapid and accurate diagnosis of malaria in this region.
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Understanding the Mechanism of Bacterial Biofilms Resistance to Antimicrobial Agents
Singh, Shriti; Singh, Santosh Kumar; Chowdhury, Indrajit; Singh, Rajesh
2017-01-01
A biofilm is a group of microorganisms, that causes health problems for the patients with indwelling medical devices via attachment of cells to the surface matrix. It increases the resistance of a microorganism for antimicrobial agents and developed the human infection. Current strategies are removed or prevent the microbial colonies from the medical devices, which are attached to the surfaces. This will improve the clinical outcomes in favor of the patients suffering from serious infectious diseases. Moreover, the identification and inhibition of genes, which have the major role in biofilm formation, could be the effective approach for health care systems. In a current review article, we are highlighting the biofilm matrix and molecular mechanism of antimicrobial resistance in bacterial biofilms. PMID:28553416
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Candida tropicalis biofilm inhibition by ZnO nanoparticles and EDTA.
Jothiprakasam, Vinoth; Sambantham, Murugan; Chinnathambi, Stalin; Vijayaboopathi, Singaravel
2017-01-01
Biofilm of Candida tropicalis denote as a complex cellular congregation with major implication in pathogenesis. This lifestyle of fungus as a biofilm can inhibit immune system and antifungal therapy in treatment of infectious disease especially medical device associated chronic disease. In this study effects of Zinc Oxide (ZnO) nanoparticles and EDTA were evaluated on C. tropicalis biofilm by using different techniques. ZnO nanoparticles were synthesized from Egg albumin. To assay the formation of biofilm of yeast cells like Fluconazole-susceptible C. tropicalis (ATCC 13,803) and fluconazole-resistant standard strains of C. tropicalis (ATCC 750) were grown in 24 well plates and antifungal effect of ZnO and EDTA were evaluated on C. tropicalis biofilm using ATP bioluminescence and tetrasodium salt (XTT) reduction assays. Synthesized ZnO NPs and EDTA had effective antifungal properties at the concentration of 5.2, 8.6μg/ml for Fluconazole susceptible strain and 5.42, 10.8μg/ml Fluconazole resistant strains of C. tropicalis biofilms compared to fluconazole drug. In present study we conclude, ZnO considered as a new agent in field of prevention C. tropicalis biofilms especially biofilms formed surface of medical device. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Electrochemically active biofilms: facts and fiction. A review
Babauta, Jerome; Renslow, Ryan; Lewandowski, Zbigniew; Beyenal, Haluk
2014-01-01
This review examines the electrochemical techniques used to study extracellular electron transfer in the electrochemically active biofilms that are used in microbial fuel cells and other bioelectrochemical systems. Electrochemically active biofilms are defined as biofilms that exchange electrons with conductive surfaces: electrodes. Following the electrochemical conventions, and recognizing that electrodes can be considered reactants in these bioelectrochemical processes, biofilms that deliver electrons to the biofilm electrode are called anodic, ie electrode-reducing, biofilms, while biofilms that accept electrons from the biofilm electrode are called cathodic, ie electrode-oxidizing, biofilms. How to grow these electrochemically active biofilms in bioelec-trochemical systems is discussed and also the critical choices made in the experimental setup that affect the experimental results. The reactor configurations used in bioelectrochemical systems research are also described and the authors demonstrate how to use selected voltammetric techniques to study extracellular electron transfer in bioelectrochemical systems. Finally, some critical concerns with the proposed electron transfer mechanisms in bioelectrochemical systems are addressed together with the prospects of bioelectrochemical systems as energy-converting and energy-harvesting devices. PMID:22856464
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Provision of Coordinated Care for Individuals with Down Syndrome: The Calgary Perspective
ERIC Educational Resources Information Center
Heerensperger, Donna
2006-01-01
In Calgary, Alberta, Canada, cooperation between families, agencies and health care providers has resulted in services that improve the health and quality of life for individuals with Down syndrome. One of these is the multidisciplinary Down syndrome team at the Alberta Children's Hospital, which provides assessment, treatment and support based on…
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Phytochemicals as Inhibitors of Candida Biofilm.
Raut, Jayant Shankar; Karuppayil, Sankunny Mohan
2016-01-01
Candida biofilm and associated infections is a serious threat to the large population of immunocompromised patients. Biofilm growth on prosthetic devices or host tissue shows reduced sensitivity to antifungal agents and persists as a reservoir of infective cells. Options for successful treatment of biofilm associated Candida infections are restricted because most of the available antifungal drugs fail to eradicate biofilms. Various plant actives are known to possess interesting antifungal properties. To explore and review the potential of phytochemicals as a novel strategy against Candida biofilms is the intent of present article. Thorough literature search is performed to identify Candida biofilm inhibitors of plant origin. An account of efficacy of selected phytochemicals is presented taking into consideration their biofilm inhibitory concentrations. This review discusses biofilm formation by Candida species, their involvement in human infections, and associated drug resistance. It gives insight into the biofilm inhibitory potential of various phytochemicals. Based on the available reports including the work done in our laboratory, several plant extracts, essential oils and phytomolecules have been identified as excellent inhibitors of biofilms of C. albicans and non-albicans Candida species (NACS). Selected phytochemicals which exhibit activities at low concentrations without displaying toxicity to host are potential therapeutic agents against biofilm associated Candida infections. In vivo testing in animal models and clinical trials in humans are required to be taken up seriously to propose few of the phytochemicals as candidate drug molecules.
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[Biofilms and their significance in medical microbiology].
Cernohorská, L; Votava, M
2002-11-01
Microorganisms are able to adhere to various surfaces and to form there a three-dimensional structure known as biofilm. In biofilms, microbial cells show characteristics and behaviours different from those of plankton cells. Intercellular signalizations of the quorum-sensing type regulate interaction between members of the biofilm. Bacteria embedded in the biofilm can escape and form well known planktonic forms, that are obviously only a part of the bacterial life cycle. Bacteria adhere also to medically important surfaces such as catheters, either urinary or intravenous ones, artificial heart valves, orthopedic implants and so on and contribute to device-related infections like cystitis, catheter-related sepsis, endocarditis etc. Once a biofilm has been established on a surface, the bacteria harboured inside are less exposed to the host's immune response and less susceptible to antibiotics. As an important cause of nosocomial infections the biofilm must remain in the centre of the microbiologist's attention.
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Medical biofilms--nanotechnology approaches.
Neethirajan, Suresh; Clond, Morgan A; Vogt, Adam
2014-10-01
Biofilms are colonies of bacteria or fungi that adhere to a surface, protected by an extracellular polymer matrix composed of polysaccharides and extracellular DNA. They are highly complex and dynamic multicellular structures that resist traditional means of killing planktonic bacteria. Recent developments in nanotechnology provide novel approaches to preventing and dispersing biofilm infections, which are a leading cause of morbidity and mortality. Medical device infections are responsible for approximately 60% of hospital acquired infections. In the United States, the estimated cost of caring for healthcare-associated infections is approximately between $28 billion and $45 billion per year. In this review, we will discuss our current understanding of biofilm formation and degradation, its relevance to challenges in clinical practice, and new technological developments in nanotechnology that are designed to address these challenges.
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NASA Astrophysics Data System (ADS)
Abraham, Nabil Mathew
Staphylococcus aureus is the causative agent of a diverse array of acute and chronic infections, and some these infections, including infective endocarditis, joint infections, and medical device-associated bloodstream infections, depend upon its capacity to form tenacious biofilms on surfaces. Inserted medical devices such as intravenous catheters, pacemakers, and artificial heart valves save lives, but unfortunately, they can also serve as a substrate on which S. aureus can form a biofilm, attributing S. aureus as a leading cause of medical device-related infections. The major aim of this work was take compounds to which S. aureus would be exposed during infection and to investigate their effects on its capacity to form a biofilm. More specifically, the project investigated the effects of serum, and thereafter of catheter lock solutions on biofilm formation by S. aureus. Pre-coating polystyrene with serum is frequently used as a method to augment biofilm formation. The effect of pre-coating with serum is due to the deposition of extracellular matrix components onto the polystyrene, which are then recognized by MSCRAMMs. We therefore hypothesized that the major component of blood, serum, would induce biofilm formation. Surprisingly, serum actually inhibited biofilm formation. The inhibitory activity was due to a small molecular weight, heat-stable, non-proteinaceous component/s of serum. Serum-mediated inhibition of biofilm formation may represent a previously uncharacterized aspect of host innate immunity that targets the expression of a key bacterial virulence factor: the ability to establish a resistant biofilm. Metal ion chelators like sodium citrate are frequently chosen to lock intravenous catheters because they are regarded as potent inhibitors of bacterial biofilm formation and viability. We found that, while chelating compounds abolished biofilm formation in most strains of S. aureus, they actually augmented the phenotype in a subset of strains. We
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Rat Indwelling Urinary Catheter Model of Candida albicans Biofilm Infection
Nett, Jeniel E.; Brooks, Erin G.; Cabezas-Olcoz, Jonathan; Sanchez, Hiram; Zarnowski, Robert; Marchillo, Karen
2014-01-01
Indwelling urinary catheters are commonly used in the management of hospitalized patients. Candida can adhere to the device surface and propagate as a biofilm. These Candida biofilm communities differ from free-floating Candida, exhibiting high tolerance to antifungal therapy. The significance of catheter-associated candiduria is often unclear, and treatment may be problematic considering the biofilm drug-resistant phenotype. Here we describe a rodent model for the study of urinary catheter-associated Candida albicans biofilm infection that mimics this common process in patients. In the setting of a functioning, indwelling urinary catheter in a rat, Candida proliferated as a biofilm on the device surface. Characteristic biofilm architecture was observed, including adherent, filamentous cells embedded in an extracellular matrix. Similar to what occurs in human patients, animals with this infection developed candiduria and pyuria. Infection progressed to cystitis, and a biofilmlike covering was observed over the bladder surface. Furthermore, large numbers of C. albicans cells were dispersed into the urine from either the catheter or bladder wall biofilm over the infection period. We successfully utilized the model to test the efficacy of antifungals, analyze transcriptional patterns, and examine the phenotype of a genetic mutant. The model should be useful for future investigations involving the pathogenesis, diagnosis, therapy, prevention, and drug resistance of Candida biofilms in the urinary tract. PMID:25183731
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Cold Plasmas for Biofilm Control: Opportunities and Challenges.
Gilmore, Brendan F; Flynn, Padrig B; O'Brien, Séamus; Hickok, Noreen; Freeman, Theresa; Bourke, Paula
2018-06-01
Bacterial biofilm infections account for a major proportion of chronic and medical device associated infections in humans, yet our ability to control them is compromised by their inherent tolerance to antimicrobial agents. Cold atmospheric plasma (CAP) represents a promising therapeutic option. CAP treatment of microbial biofilms represents the convergence of two complex phenomena: the production of a chemically diverse mixture of reactive species and intermediates, and their interaction with a heterogeneous 3D interface created by the biofilm extracellular polymeric matrix. Therefore, understanding these interactions and physiological responses to CAP exposure are central to effective management of infectious biofilms. We review the unique opportunities and challenges for translating CAP to the management of biofilms. Copyright © 2018. Published by Elsevier Ltd.
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Figueiredo, Agnes Marie Sá; Ferreira, Fabienne Antunes; Beltrame, Cristiana Ossaille; Côrtes, Marina Farrel
2017-09-01
Staphylococcus aureus biofilms represent a unique micro-environment that directly contribute to the bacterial fitness within hospital settings. The accumulation of this structure on implanted medical devices has frequently caused the development of persistent and chronic S. aureus-associated infections, which represent an important social and economic burden worldwide. ica-independent biofilms are composed of an assortment of bacterial products and modulated by a multifaceted and overlapping regulatory network; therefore, biofilm composition can vary among S. aureus strains. In the microniches formed by biofilms-produced by a number of bacterial species and composed by different structural components-drug refractory cell subpopulations with distinct physiological characteristics can emerge and result in therapeutic failures in patients with recalcitrant bacterial infections. In this review, we highlight the importance of biofilms in the development of persistence and chronicity in some S. aureus diseases, the main molecules associated with ica-independent biofilm development and the regulatory mechanisms that modulate ica-independent biofilm production, accumulation, and dispersion.
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Time to "go large" on biofilm research: advantages of an omics approach.
Azevedo, Nuno F; Lopes, Susana P; Keevil, Charles W; Pereira, Maria O; Vieira, Maria J
2009-04-01
In nature, the biofilm mode of life is of great importance in the cell cycle for many microorganisms. Perhaps because of biofilm complexity and variability, the characterization of a given microbial system, in terms of biofilm formation potential, structure and associated physiological activity, in a large-scale, standardized and systematic manner has been hindered by the absence of high-throughput methods. This outlook is now starting to change as new methods involving the utilization of microtiter-plates and automated spectrophotometry and microscopy systems are being developed to perform large-scale testing of microbial biofilms. Here, we evaluate if the time is ripe to start an integrated omics approach, i.e., the generation and interrogation of large datasets, to biofilms--"biofomics". This omics approach would bring much needed insight into how biofilm formation ability is affected by a number of environmental, physiological and mutational factors and how these factors interplay between themselves in a standardized manner. This could then lead to the creation of a database where biofilm signatures are identified and interrogated. Nevertheless, and before embarking on such an enterprise, the selection of a versatile, robust, high-throughput biofilm growing device and of appropriate methods for biofilm analysis will have to be performed. Whether such device and analytical methods are already available, particularly for complex heterotrophic biofilms is, however, very debatable.
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Anti-biofilm peptides as a new weapon in antimicrobial warfare.
Pletzer, Daniel; Coleman, Shannon R; Hancock, Robert Ew
2016-10-01
Microorganisms growing in a biofilm state are very resilient in the face of treatment by many antimicrobial agents. Biofilm infections are a significant problem in chronic and long-term infections, including those colonizing medical devices and implants. Anti-biofilm peptides represent a very promising approach to treat biofilm-related infections and have an extraordinary ability to interfere with various stages of the biofilm growth mode. Anti-biofilm peptides possess promising broad-spectrum activity in killing both Gram-positive and Gram-negative bacteria in biofilms, show strong synergy with conventional antibiotics, and act by targeting a universal stringent stress response. Understanding downstream processes at the molecular level will help to develop and design peptides with increased activity. Anti-biofilm peptides represent a novel, exciting approach to treating recalcitrant bacterial infections. Copyright © 2016 Elsevier Ltd. All rights reserved.
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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
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Potential of shock waves to remove calculus and biofilm.
Müller, Philipp; Guggenheim, Bernhard; Attin, Thomas; Marlinghaus, Ernst; Schmidlin, Patrick R
2011-12-01
Effective calculus and biofilm removal is essential to treat periodontitis. Sonic and ultrasonic technologies are used in several scaler applications. This was the first feasibility study to assess the potential of a shock wave device to remove calculus and biofilms and to kill bacteria. Ten extracted teeth with visible subgingival calculus were treated with either shock waves for 1 min at an energy output of 0.4 mJ/mm(2) at 3 Hz or a magnetostrictive ultrasonic scaler at medium power setting for 1 min, which served as a control. Calculus was determined before and after treatment planimetrically using a custom-made software using a grey scale threshold. In a second experiment, multispecies biofilms were formed on saliva-preconditioned bovine enamel discs during 64.5 h. They were subsequently treated with shock waves or the ultrasonic scaler (N = 6/group) using identical settings. Biofilm detachment and bactericidal effects were then assessed. Limited efficiency of the shock wave therapy in terms of calculus removal was observed: only 5% of the calculus was removed as compared to 100% when ultrasound was used (P ≤ 0.0001). However, shock waves were able to significantly reduce adherent bacteria by three orders of magnitude (P ≤ 0.0001). The extent of biofilm removal by the ultrasonic device was statistically similar. Only limited bactericidal effects were observed using both methods. Within the limitations of this preliminary study, the shock wave device was not able to reliably remove calculus but had the potential to remove biofilms by three log steps. To increase the efficacy, technical improvements are still required. This novel noninvasive intervention, however, merits further investigation.
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Candida albicans Biofilms and Human Disease
Nobile, Clarissa J.; Johnson, Alexander D.
2016-01-01
In humans, microbial cells (including bacteria, archaea, and fungi) greatly outnumber host cells. Candida albicans is the most prevalent fungal species of the human microbiota; this species asymptomatically colonizes many areas of the body, particularly the gastrointestinal and genitourinary tracts of healthy individuals. Alterations in host immunity, stress, resident microbiota, and other factors can lead to C. albicans overgrowth, causing a wide range of infections, from superficial mucosal to hematogenously disseminated candidiasis. To date, most studies of C. albicans have been carried out in suspension cultures; however, the medical impact of C. albicans (like that of many other microorganisms) depends on its ability to thrive as a biofilm, a closely packed community of cells. Biofilms are notorious for forming on implanted medical devices, including catheters, pacemakers, dentures, and prosthetic joints, which provide a surface and sanctuary for biofilm growth. C. albicans biofilms are intrinsically resistant to conventional antifungal therapeutics, the host immune system, and other environmental perturbations, making biofilm-based infections a significant clinical challenge. Here, we review our current knowledge of biofilms formed by C. albicans and closely related fungal species. PMID:26488273
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Hsp90 Governs Dispersion and Drug Resistance of Fungal Biofilms
Nett, Jeniel; Rajendran, Ranjith; Ramage, Gordon; Lopez-Ribot, Jose L.; Andes, David; Cowen, Leah E.
2011-01-01
Fungal biofilms are a major cause of human mortality and are recalcitrant to most treatments due to intrinsic drug resistance. These complex communities of multiple cell types form on indwelling medical devices and their eradication often requires surgical removal of infected devices. Here we implicate the molecular chaperone Hsp90 as a key regulator of biofilm dispersion and drug resistance. We previously established that in the leading human fungal pathogen, Candida albicans, Hsp90 enables the emergence and maintenance of drug resistance in planktonic conditions by stabilizing the protein phosphatase calcineurin and MAPK Mkc1. Hsp90 also regulates temperature-dependent C. albicans morphogenesis through repression of cAMP-PKA signalling. Here we demonstrate that genetic depletion of Hsp90 reduced C. albicans biofilm growth and maturation in vitro and impaired dispersal of biofilm cells. Further, compromising Hsp90 function in vitro abrogated resistance of C. albicans biofilms to the most widely deployed class of antifungal drugs, the azoles. Depletion of Hsp90 led to reduction of calcineurin and Mkc1 in planktonic but not biofilm conditions, suggesting that Hsp90 regulates drug resistance through different mechanisms in these distinct cellular states. Reduction of Hsp90 levels led to a marked decrease in matrix glucan levels, providing a compelling mechanism through which Hsp90 might regulate biofilm azole resistance. Impairment of Hsp90 function genetically or pharmacologically transformed fluconazole from ineffectual to highly effective in eradicating biofilms in a rat venous catheter infection model. Finally, inhibition of Hsp90 reduced resistance of biofilms of the most lethal mould, Aspergillus fumigatus, to the newest class of antifungals to reach the clinic, the echinocandins. Thus, we establish a novel mechanism regulating biofilm drug resistance and dispersion and that targeting Hsp90 provides a much-needed strategy for improving clinical outcome in the
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Bacterial and fungal biofilm formation on anodized titanium alloys with fluorine.
Perez-Jorge, Concepcion; Arenas, Maria-Angeles; Conde, Ana; Hernández-Lopez, Juan-Manuel; de Damborenea, Juan-Jose; Fisher, Steve; Hunt, Alessandra M Agostinho; Esteban, Jaime; James, Garth
2017-01-01
Orthopaedic device-related infections are closely linked to biofilm formation on the surfaces of these devices. Several modified titanium (Ti-6Al-4V) surfaces doped with fluorine were studied in order to evaluate the influence of these modifications on biofilm formation by Gram-positive and Gram-negative bacteria as well as a yeast. The biofilm studies were performed according to the standard test method approved by ASTM (Designation: E2196-12) using the Rotating Disk Reactor. Four types of Ti-6Al-4V samples were tested; chemically polished (CP), two types of nanostructures containing fluorine, nanoporous (NP) and nanotubular (NT), and non-nanostructured fluorine containing samples (fluoride barrier layers, FBL). Different species of Gram-positive cocci, (Staphylococcus aureus and epidermidis), Gram-negative rods (Escherichia coli, Pseudomonas aeruginosa), and a yeast (Candida albicans) were studied. For one of the Gram-positive (S. epidermidis) and one of the Gram-negative (E. coli) species a statistically-significant decrease in biofilm accumulation for NP and NT samples was found when compared with the biofilm accumulation on CP samples. The results suggest an effect of the modified materials on the biofilm formation.
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Marketing the University of Calgary to Frosh: A Motivational Typology of Student-College Choice.
ERIC Educational Resources Information Center
Barnetson, Robert James
This thesis proposes a segmentation of the University of Calgary's (Canada) freshman class based on benefits sought from attendance and provides descriptions of each benefit segment that includes the impact of institutional characteristics. A motivational typology for university participation is presented and the marketing implications of this…
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NASA Astrophysics Data System (ADS)
Jun, Won; Kim, Moon S.; Chao, Kaunglin; Lefcourt, Alan M.; Roberts, Michael S.; McNaughton, James L.
2009-05-01
We used a portable hyperspectral fluorescence imaging system to evaluate biofilm formations on four types of food processing surface materials including stainless steel, polypropylene used for cutting boards, and household counter top materials such as formica and granite. The objective of this investigation was to determine a minimal number of spectral bands suitable to differentiate microbial biofilm formation from the four background materials typically used during food processing. Ultimately, the resultant spectral information will be used in development of handheld portable imaging devices that can be used as visual aid tools for sanitation and safety inspection (microbial contamination) of the food processing surfaces. Pathogenic E. coli O157:H7 and Salmonella cells were grown in low strength M9 minimal medium on various surfaces at 22 +/- 2 °C for 2 days for biofilm formation. Biofilm autofluorescence under UV excitation (320 to 400 nm) obtained by hyperspectral fluorescence imaging system showed broad emissions in the blue-green regions of the spectrum with emission maxima at approximately 480 nm for both E. coli O157:H7 and Salmonella biofilms. Fluorescence images at 480 nm revealed that for background materials with near-uniform fluorescence responses such as stainless steel and formica cutting board, regardless of the background intensity, biofilm formation can be distinguished. This suggested that a broad spectral band in the blue-green regions can be used for handheld imaging devices for sanitation inspection of stainless, cutting board, and formica surfaces. The non-uniform fluorescence responses of granite make distinctions between biofilm and background difficult. To further investigate potential detection of the biofilm formations on granite surfaces with multispectral approaches, principal component analysis (PCA) was performed using the hyperspectral fluorescence image data. The resultant PCA score images revealed distinct contrast between
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Gusnaniar, Niar; Sjollema, Jelmer; Jong, Ed D; Woudstra, Willem; de Vries, Joop; Nuryastuti, Titik; van der Mei, Henny C; Busscher, Henk J
2017-11-01
In real-life situations, bacteria are often transmitted from biofilms growing on donor surfaces to receiver ones. Bacterial transmission is more complex than adhesion, involving bacterial detachment from donor and subsequent adhesion to receiver surfaces. Here, we describe a new device to study shear-induced bacterial transmission from a (stainless steel) pipe to a (silicone rubber) tube and compare transmission of EPS-producing and non-EPS-producing staphylococci. Transmission of an entire biofilm from the donor to the receiver tube did not occur, indicative of cohesive failure in the biofilm rather than of adhesive failure at the donor-biofilm interface. Biofilm was gradually transmitted over an increasing length of receiver tube, occurring mostly to the first 50 cm of the receiver tube. Under high-shearing velocity, transmission of non-EPS-producing bacteria to the second half decreased non-linearly, likely due to rapid thinning of the lowly lubricious biofilm. Oppositely, transmission of EPS-producing strains to the second tube half was not affected by higher shearing velocity due to the high lubricity and stress relaxation of the EPS-rich biofilms, ensuring continued contact with the receiver. The non-linear decrease of ongoing bacterial transmission under high-shearing velocity is new and of relevance in for instance, high-speed food slicers and food packaging. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.
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Effects of bacteriocins on methicillin-resistant Staphylococcus aureus biofilm.
Okuda, Ken-ichi; Zendo, Takeshi; Sugimoto, Shinya; Iwase, Tadayuki; Tajima, Akiko; Yamada, Satomi; Sonomoto, Kenji; Mizunoe, Yoshimitsu
2013-11-01
Control of biofilms formed by microbial pathogens is an important subject for medical researchers, since the development of biofilms on foreign-body surfaces often causes biofilm-associated infections in patients with indwelling medical devices. The present study examined the effects of different kinds of bacteriocins, which are ribosomally synthesized antimicrobial peptides produced by certain bacteria, on biofilms formed by a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA). The activities and modes of action of three bacteriocins with different structures (nisin A, lacticin Q, and nukacin ISK-1) were evaluated. Vancomycin, a glycopeptide antibiotic used in the treatment of MRSA infections, showed bactericidal activity against planktonic cells but not against biofilm cells. Among the tested bacteriocins, nisin A showed the highest bactericidal activity against both planktonic cells and biofilm cells. Lacticin Q also showed bactericidal activity against both planktonic cells and biofilm cells, but its activity against biofilm cells was significantly lower than that of nisin A. Nukacin ISK-1 showed bacteriostatic activity against planktonic cells and did not show bactericidal activity against biofilm cells. Mode-of-action studies indicated that pore formation leading to ATP efflux is important for the bactericidal activity against biofilm cells. Our results suggest that bacteriocins that form stable pores on biofilm cells are highly potent for the treatment of MRSA biofilm infections.
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Effects of Bacteriocins on Methicillin-Resistant Staphylococcus aureus Biofilm
Zendo, Takeshi; Sugimoto, Shinya; Iwase, Tadayuki; Tajima, Akiko; Yamada, Satomi; Sonomoto, Kenji
2013-01-01
Control of biofilms formed by microbial pathogens is an important subject for medical researchers, since the development of biofilms on foreign-body surfaces often causes biofilm-associated infections in patients with indwelling medical devices. The present study examined the effects of different kinds of bacteriocins, which are ribosomally synthesized antimicrobial peptides produced by certain bacteria, on biofilms formed by a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA). The activities and modes of action of three bacteriocins with different structures (nisin A, lacticin Q, and nukacin ISK-1) were evaluated. Vancomycin, a glycopeptide antibiotic used in the treatment of MRSA infections, showed bactericidal activity against planktonic cells but not against biofilm cells. Among the tested bacteriocins, nisin A showed the highest bactericidal activity against both planktonic cells and biofilm cells. Lacticin Q also showed bactericidal activity against both planktonic cells and biofilm cells, but its activity against biofilm cells was significantly lower than that of nisin A. Nukacin ISK-1 showed bacteriostatic activity against planktonic cells and did not show bactericidal activity against biofilm cells. Mode-of-action studies indicated that pore formation leading to ATP efflux is important for the bactericidal activity against biofilm cells. Our results suggest that bacteriocins that form stable pores on biofilm cells are highly potent for the treatment of MRSA biofilm infections. PMID:23979748
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Polysorbate 80 and polymyxin B inhibit Stenotrophomonas maltophilia biofilm.
Malinowski, Adam M; McClarty, Bryan M; Robinson, Carolyn; Spear, William; Sanchez, Maria; Sparkes, Timothy C; Brooke, Joanna S
2017-02-01
Stenotrophomonas maltophilia is an opportunistic multiple-drug-resistant human pathogen that forms biofilms on implanted medical devices. We examined the potential inhibitory activity of polysorbate 80 and polymyxin B against S. maltophilia. A combination of subMIC polymyxin B and polysorbate 80 was the most effective inhibitor of growth and biofilm formation. Copyright © 2016 Elsevier Inc. All rights reserved.
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Enhanced drug transport through alginate biofilms using magnetic nanoparticles
NASA Astrophysics Data System (ADS)
McGill, Shayna L.; Cuylear, Carla; Adolphi, Natalie L.; Osinski, Marek; Smyth, Hugh
2009-02-01
The development of microbiological biofilms greatly reduces the efficacy of antibiotic therapies and is a serious problem in chronic infection and for implantable medical devices. We investigated the potential of superparamagnetic nanoparticles to increase transport through in vitro models of alginate biofilms. An in vitro alginate biofilm model was developed to mimic the composition of in vivo samples of P. aeruginosa infections. Transport through this model biofilm was performed using both bulk diffusion methods and single particle tracking techniques in the presence and absence of an external magnetic field. Bulk diffusion of nanoparticles through the biofilm was significantly enhanced in the presence of a magnetic field, both visually and quantitatively. Nanoparticle trajectories also showed transport increases were significantly higher when magnetic fields were applied. We also showed that surface chemistry (cationic, anioni, or neutral) of the nanoparticles significantly influenced transport rates. Finally, nanoparticle size also influenced the transport rates and variability of transport rates through the biofilm. In these first studies using magnetic nanoparticles in bacterial biofilms, we demonstrate that transport enhancement can be achieved and further studies are warranted.
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Intercellular adhesion and biocide resistance in nontypeable Haemophilus influenzae biofilms
Izano, Era A.; Shah, Suhagi M.; Kaplan, Jeffrey B.
2009-01-01
Respiratory infections caused by nontypeable Haemophilus influenzae (NTHi) are a major medical problem. Evidence suggests that the ability to form biofilms on mucosal surfaces may play a role in NTHi pathogenesis. However, the factors that contribute to NTHi biofilm cohesion remain largely unknown. In this study we investigated the biofilm growth and detachment phenotypes of eight NTHi clinical strains in vitro. We found that the majority of strains produced biofilms within 6 hours when cultured statically in tubes. Biofilm formation was inhibited when culture medium was supplemented with proteinase K or DNase I. Both enzymes also caused significant detachment of pre-formed NTHi biofilms. These findings indicate that both proteinaceous adhesins and extracellular DNA contribute to NTHi biofilm cohesion. Treatment of NTHi biofilms cultured in centrifugal filter devices with DNase I, but not with proteinase K, caused a significant decrease in fluid convection through the biofilms. These results suggest that extracellular DNA is the major volumetric component of the NTHi biofilm matrix. Mechanical or enzymatic disruption of NTHi biofilms cultured in microtiter plates significantly increased their sensitivity to killing by SDS, cetylpyridinium chloride, chlorhexidine gluconate, povidone iodine and sodium hypochlorite. These findings indicate that biocide resistance in NTHi biofilms is mediated to a large part by the cohesive and protective properties of the biofilm matrix. Understanding the mechanisms of biofilm cohesion and biocide resistance in NTHi biofilms may lead to new methods for treating NTHi-associated infections. PMID:19490830
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Plant Biofilm Inhibitors to Discover Biofilm Genes
2011-04-08
REPORT Final Report for Plant Biofilm Inhibitors to Discover Biofilm Genes 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: To control biofilms , we have...synthesized the natural biofilm inhibitor (5Z)-4-bromo-5-(bromomethylene) -3-butyl-2(5H)-furanone from the red alga Delisea pulchra and determined that...Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS biofilms , biofilm inhibitors Thomas K. Wood Texas Engineering
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Martinez, Raquel M; Bowen, Thomas R; Foltzer, Michael A
2016-08-01
The immunocompromised host is a particularly vulnerable population in whom routine and unusual infections can easily and frequently occur. Prosthetic devices are commonly used in these patients and the infections associated with those devices present a number of challenges for both the microbiologist and the clinician. Biofilms play a major role in device-related infections, which may contribute to failed attempts to recover organisms from routine culture methods. Moreover, device-related microorganisms can be difficult to eradicate by antibiotic therapy alone. Changes in clinical practice and advances in laboratory diagnostics have provided significant improvements in the detection and accurate diagnosis of device-related infections. Disruption of the bacterial biofilm plays an essential role in recovering the causative agent in culture. Various culture and nucleic acid amplification techniques are more accurate to guide directed treatment regimens. This chapter reviews the performance characteristics of currently available diagnostic assays and summarizes published guidelines, where available, for addressing suspected infected prosthetic devices.
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Leuba, Kohana D; Durmus, Naside Gozde; Taylor, Erik N; Webster, Thomas J
2013-01-01
Biofilms formed by antibiotic resistant Staphylococcus aureus (S. aureus) continue to be a problem for medical devices. Antibiotic resistant bacteria (such as S. aureus) often complicate the treatment and healing of the patient, yet, medical devices are needed to heal such patients. Therefore, methods to treat these Biofilms once formed on medical devices are badly needed. Due to their small size and magnetic properties, superparamagnetic iron oxide nanoparticles (SPION) may be one possible material to penetrate Biofilms and kill or slow the growth of bacteria. In this study, SPION were functionalized with amine, carboxylate, and isocyanate functional groups to further improve their efficacy to disrupt the growth of S. aureus Biofilms. Without the use of antibiotics, results showed that SPION functionalized with carboxylate groups (followed by isocyanate then amine functional groups then unfunctionalized SPION) significantly disrupted Biofilms and retarded the growth of S. aureus compared to untreated Biofilms (by over 35% after 24 hours). PMID:23450111
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Tachikawa, Mariko
2017-01-01
The formation of bacterial biofilms and their disinfection and removal have been important subjects in the maintenance of water quality in areas such as public spas, swimming pools, food processing lines, industrial water systems, and in the hygienic control of medical devices, hospital procedures, etc. Presented here is an outline of biofilm formation, as well as studies on the disinfection and removal of biofilms by oxidizing biocides using established biofilms. These studies using established biofilms may increase the understanding of the variable response of biofilms to planktonic bacteria, and the unique aspects of oxidizing biocides in the disinfection and removal of biofilms.
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Casillo, Angela; Papa, Rosanna; Ricciardelli, Annarita; Sannino, Filomena; Ziaco, Marcello; Tilotta, Marco; Selan, Laura; Marino, Gennaro; Corsaro, Maria M.; Tutino, Maria L.; Artini, Marco; Parrilli, Ermenegilda
2017-01-01
Staphylococcus epidermidis is a harmless human skin colonizer responsible for ~20% of orthopedic device-related infections due to its capability to form biofilm. Nowadays there is an interest in the development of anti-biofilm molecules. Marine bacteria represent a still underexploited source of biodiversity able to synthesize a broad range of bioactive compounds, including anti-biofilm molecules. Previous results have demonstrated that the culture supernatant of Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125 impairs the formation of S. epidermidis biofilm. Further, evidence supports the hydrophobic nature of the active molecule, which has been suggested to act as a signal molecule. In this paper we describe an efficient activity-guided purification protocol which allowed us to purify this anti-biofilm molecule and structurally characterize it by NMR and mass spectrometry analyses. Our results demonstrate that the anti-biofilm molecule is pentadecanal, a long-chain fatty aldehyde, whose anti-S. epidermidis biofilm activity has been assessed using both static and dynamic biofilm assays. The specificity of its action on S. epidermidis biofilm has been demonstrated by testing chemical analogs of pentadecanal differing either in the length of the aliphatic chain or in their functional group properties. Further, indications of the mode of action of pentadecanal have been collected by studying the bioluminescence of a Vibrio harveyi reporter strain for the detection of autoinducer AI-2 like activities. The data collected suggest that pentadecanal acts as an AI-2 signal. Moreover, the aldehyde metabolic role and synthesis in the Antarctic source strain has been investigated. To the best of our knowledge, this is the first report on the identification of an anti-biofilm molecule form from cold-adapted bacteria and on the action of a long-chain fatty aldehyde acting as an anti-biofilm molecule against S. epidermidis. PMID:28280714
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Reasons for testing women for genital Chlamydia trachomatis infection in the Calgary region
Church, Deirdre L; Zentner, Ali; Semeniuk, Heather; Henderson, Elizabeth; Read, Ron
2003-01-01
OBJECTIVE: To determine the clinical reason(s) for screening women with varying degrees of risk for genital Chlamydia trachomatis (CT) in the Calgary region. DESIGN: Women aged 15 to 75 years were enrolled at various patient care locations. Pertinent risk factors for genital CT infection were recorded and a gynecological examination was performed. Two endocervical swabs and a first-void urine sample were collected for CT detection using two different nucleic acid amplification test methods. SETTING: Calgary is an urban region that provides healthcare services to a population of almost one million people. Microbiology services are provided by Calgary Laboratory Services through a centralized regional laboratory service. MAIN RESULTS: 504 women with a mean age of 28.1 ±SD 8.22 years were enrolled. Two hundred ninety-one women (57.8%) were at high risk for acquiring genital CT infection. Twenty-eight (5.6%) tested positive for CT infection and almost all of these women (26 of 28, 93%) had risk factors for acquiring infection. Of the high-risk women, 9.8% were CT positive versus only 1.3% of women at low risk (P=0.0001). Only two of 152 (1.3%) women older than 30 years had genital CT infections. Although most women were asymptomatic, those with laboratory-confirmed CT infection were more likely to have genitourinary symptoms. Three hundred forty-three of 476 (72%) women who did not have genital CT infection had no risk factors, and screening was done as part of a routine gynecological examination for other purposes (prenatal visit, Pap smear). CONCLUSION: Women without risk factors are being screened routinely for genital CT infection as part of a routine gynecological examination done for other reasons. Elimination of the routine screening of low-risk women older than 30 years of age would decrease the current regional utilization of CT tests by as much as one-third. PMID:18159423
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NASA Astrophysics Data System (ADS)
Salta, M.; Goodes, L. R.; Maas, B. J.; Dennington, S. P.; Secker, T. J.; Leighton, T. G.
2016-09-01
The accumulation of marine organisms on a range of manmade surfaces, termed biofouling, has proven to be the Achilles’ heel of the shipping industry. Current antifouling coatings, such as foul release coatings (FRCs), only partially inhibit biofouling, since biofilms remain a major issue. Mechanical ship hull cleaning is commonly employed to remove biofilms, but these methods tend to damage the antifouling coating and often do not result in full removal. Here, we report the effectiveness of biofilm removal from FRCs through a novel cleaning device that uses an ultrasonically activated stream (UAS). In this device, ultrasound enhances the cleaning properties of microbubbles in a freely flowing stream of water. The UAS was applied on two types of commercial FRCs which were covered with biofilm growth following twelve days immersion in the marine environment. Biofilm removal was quantified in terms of reduction in biovolume and surface roughness, both measured using an optical profilometer, which were then compared with similar measurements after cleaning with a non-ultrasonically activated water stream. It was found that the UAS significantly improves the cleaning capabilities of a water flow, up to the point where no detectable biofilm remained on the coating surfaces. Overall biofilm surface coverage was significantly lower on the FRC coatings cleaned with the UAS system when compared to the coatings cleaned with water or not cleaned at all. When biofilm biomass removal was investigated, the UAS system resulted in significantly lower biovolume values even when compared to the water cleaning treatment with biovolume values close to zero. Remarkably, the surface roughness of the coatings after cleaning with the UAS was found to be comparable to that of the blank, non-immersed coatings, illustrating that the UAS did not damage the coatings in the process. The data supporting this study are openly available from the University of Southampton repository at http
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López, Daniel; Vlamakis, Hera; Kolter, Roberto
2010-07-01
The ability to form biofilms is a universal attribute of bacteria. Biofilms are multicellular communities held together by a self-produced extracellular matrix. The mechanisms that different bacteria employ to form biofilms vary, frequently depending on environmental conditions and specific strain attributes. In this review, we emphasize four well-studied model systems to give an overview of how several organisms form biofilms: Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus. Using these bacteria as examples, we discuss the key features of biofilms as well as mechanisms by which extracellular signals trigger biofilm formation.
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The presence of biofilm forming microorganisms on hydrotherapy equipment and facilities.
Jarząb, Natalia; Walczak, Maciej
2017-10-01
Hydrotherapy equipment provides a perfect environment for the formation and growth of microbial biofilms. Biofilms may reduce the microbiological cleanliness of hydrotherapy equipment and harbour opportunistic pathogens and pathogenic bacteria. The aims of this study were to investigate the ability of microorganisms that colonize hydrotherapy equipment to form biofilms, and to assess the influence of temperature and nutrients on the rate of biofilm formation. Surface swab samples were collected from the whirlpool baths, inhalation equipment and submerged surfaces of a brine pool at the spa center in Ciechocinek, Poland. We isolated and identified microorganisms from the swab samples and measured their ability to form biofilms. Biofilm formation was observed at a range of temperatures, in both nutrient-deficient and nutrient-rich environments. We isolated and identified microorganisms which are known to form biofilms on medical devices (e.g. Stenotrophomonas maltophilia). All isolates were classified as opportunistic pathogens, which can cause infections in humans with weakened immunity systems. All isolates showed the ability to form biofilms in the laboratory conditions. The potential for biofilm formation was higher in the presence of added nutrients. In addition, the hydrolytic activity of the biofilm was connected with the presence of nutrients.
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Candida tropicalis biofilms: artificial urine, urinary catheters and flow model.
Negri, Melyssa; Silva, Sónia; Henriques, Mariana; Azeredo, Joana; Svidzinski, Terezinha; Oliveira, Rosário
2011-10-01
Adhesion to medical devices and biofilm formation are considered important virulence factors of Candida tropicalis. This work aimed to use artificial urine (AU) and urinary catheters, under flow conditions, for studying C. tropicalis biofilms. Adhesion and biofilm formation on silicone and latex urinary catheters were quantified by crystal violet staining and determination of colony forming units. Candida surface hydrophobicity was also evaluated, as well as the biofilms' matrix content in terms of proteins and carbohydrates. Candida tropicalis was able to adhere and to form biofilms along the entire length of the catheters under flow conditions. It was found that the isolate U69 adhered significantly more to both types of catheters than did the reference strain. However, U69 biofilms contained significantly less cultivable cells and higher biofilm biomass than those of the reference strain. Detachment of cells from biofilms on latex catheter was lower compared to silicone catheter. This model using AU appeared to be suitable for studies mimicking the real body conditions. Additionally, C. tropicalis was in fact able to colonize urinary catheters in the presence of AU and to detach from these catheters, demonstrating their capacity to colonize distal sites.
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Whether a novel drug delivery system can overcome the problem of biofilms in respiratory diseases?
Dua, Kamal; Shukla, Shakti D; Tekade, Rakesh K; Hansbro, Philip M
2017-02-01
Biofilm comprises a community of microorganisms which form on medical devices and can lead to various threatening infections. It is a major concern in various respiratory diseases like cystic fibrosis, chronic obstructive pulmonary disease, etc. The treatment strategies for such infections are difficult due to the resistance of the microflora existing in the biofilms against various antimicrobial agents, thus posing threats to the patient population. The present era witnesses the beginning of research to understand the biofilm physiology and the associated microfloral diversity by applying -omics approaches. There is very limited information about how the deposition of biofilm on the respiratory devices and lung itself affects the drug delivered, the delivery system, and other implications. The present mini review summarizes the basic introduction to the biofilms and its avoidance using various drug delivery systems with special emphasis on the respiratory diseases. Understanding the approaches, principles, and modes of drug delivery involved in preventing biofilm deposition will be of interest to both biological and formulation scientists, thereby opening avenues to explore the new vistas in biofilm research for identifying better treatments for pulmonary infectious diseases.
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Reduction of Escherichia coli O157:H7 in Biofilms Using Bacteriophage BPECO 19.
Sadekuzzaman, Mohammad; Yang, Sungdae; Mizan, Md Furkanur Rahaman; Ha, Sang-Do
2017-06-01
Biofilm formation is a growing concern in the food industry. Escherichia coli O157:H7 is one of the most important foodborne pathogens that can persists in food and food-related environments and subsequently produce biofilms. The efficacy of bacteriophage BPECO 19 was evaluated against three E. coli O157:H7 strains in biofilms. Biofilms of the three E. coli O157:H7 strains were grown on abiotic (stainless steel, rubber, and minimum biofilm eradication concentration [MBEC TM ] device) and biotic (lettuce) surfaces at different temperatures. The effectiveness of bacteriophage BPECO 19 in reducing preformed biofilms on these surfaces was further evaluated by treating the surfaces with a phage suspension (10 8 PFU/mL) for 2 h. The results indicated that the phage treatment significantly reduced (P < 0.05) the number of adhered cells in all the surfaces. Following phage treatment, the viability of adhered cells was reduced by ≥3 log CFU/cm 2 , 2.4 log CFU/cm 2 , and 3.1 log CFU/peg in biofilms grown on stainless steel, rubber, and the MBEC TM device, respectively. Likewise, the phage treatment reduced cell viability by ≥2 log CFU/cm 2 in biofilms grown on lettuce. Overall, these results suggested that bacteriophages such as BPECO 19 could be effective in reducing the viability of biofilm-adhered cells. © 2017 Institute of Food Technologists®.
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Greene, C; Wu, J; Rickard, A H; Xi, C
2016-10-01
The human opportunistic pathogen, Acinetobacter baumannii, has the propensity to form biofilms and frequently cause medical device-related infections in hospitals. However, the physio-chemical properties of medical surfaces, in addition to bacterial surface properties, will affect colonization and biofilm development. The objective of this study was to compare the ability of A. baumannii to form biofilms on six different materials common to the hospital environment: glass, porcelain, stainless steel, rubber, polycarbonate plastic and polypropylene plastic. Biofilms were developed on material coupons in a CDC biofilm reactor. Biofilms were visualized and quantified using fluorescent staining and imaged using confocal laser scanning microscopy (CLSM) and by direct viable cell counts. Image analysis of CLSM stacks indicated that the mean biomass values for biofilms grown on glass, rubber, porcelain, polypropylene, stainless steel and polycarbonate were 0·04, 0·26, 0·62, 1·00, 2·08 and 2·70 μm(3) /μm(2) respectively. Polycarbonate developed statistically more biofilm mass than glass, rubber, porcelain and polypropylene. Viable cell counts data were in agreement with the CLSM-derived data. In conclusion, polycarbonate was the most accommodating surface for A. baumannii ATCC 17978 to form biofilms while glass was least favourable. Alternatives to polycarbonate for use in medical and dental devices may need to be considered. In the hospital environment, Acinetobacter baumannii is one of the most persistent and difficult to control opportunistic pathogens. The persistence of A. baumannii is due, in part, to its ability to colonize surfaces and form biofilms. This study demonstrates that A. baumannii can form biofilms on a variety of different surfaces and develops substantial biofilms on polycarbonate - a thermoplastic material that is often used in the construction of medical devices. The findings highlight the need to further study the in
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Hell, E; Giske, C G; Nelson, A; Römling, U; Marchini, G
2010-02-01
The aim of this work was to investigate the possible effect of human cathelicidin antimicrobial peptide LL37 on biofilm formation of Staphylococcus epidermidis, a major causative agent of indwelling device-related infections. We performed initial attachment assay and biofilm formation solid surface assay in microtitre plates, as well as growth experiment in liquid medium using laboratory strain Staph. epidermidis ATCC35984. We found that already a low concentration of the peptide LL37 (1 mg l(-1)) significantly decreased both the attachment of bacteria to the surface and also the biofilm mass. No growth inhibition was observed even at 16 mg l(-1) concentration of LL37, indicating a direct effect of the peptide on biofilm production. As biofilm protects bacteria during infections in humans and allows their survival in a hostile environment, inhibition of biofilm formation by LL37 may have a key role to prevent bacterial colonization on indwelling devices. Our findings suggest that this host defence factor can be a potential candidate in prevention and treatment strategies of Staph. epidermidis infections in humans.
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Development and regulation of single- and multi-species Candida albicans biofilms
Lohse, Matthew B.; Gulati, Megha; Johnson, Alexander D.; Nobile, Clarissa J.
2017-01-01
Candida albicans is among the most prevalent fungal species of the human microbiota and asymptomatically colonizes healthy individuals. However, it is also an opportunistic pathogen that can cause severe, and often fatal, bloodstream infections. The medical impact of C. albicans typically depends on its ability to form biofilms, which are closely packed communities of cells that attach to surfaces, such as tissues and implanted medical devices. In this Review, we provide an overview of the processes involved in the formation of C. albicans biofilms and discuss the core transcriptional network that regulates biofilm development. We also consider some of the advantages that biofilms provide to C. albicans in comparison with planktonic growth and explore polymicrobial biofilms that are formed by C. albicans and certain bacterial species. PMID:29062072
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Williams, Dustin L; Taylor, Nicholas B; Epperson, Richard T; Rothberg, David L
2017-10-04
Flash autoclaving is one of the most frequently utilized methods of sterilizing devices, implants or other materials. For a number of decades, it has been common practice for surgeons to remove implantable devices, flash autoclave and then reimplant them in a patient. Data have not yet indicated the potential for biofilms to survive or remain on the surface of orthopaedic-relevant materials following flash autoclave. In this study, monomicrobial and polymicrobial biofilms were grown on the surface of clinically relevant titanium materials and exposed to flash autoclave settings that included varying times and temperatures. Data indicated that when the sterilization and control temperatures of an autoclave were the same, biofilms were able to survive flash autoclaving that was performed for a short duration. Higher temperature and increased duration rendered biofilms non-viable, but none of the autoclave settings had the ability to remove or disperse the presence of biofilms from the titanium surfaces. These findings may be beneficial for facilities, clinics, or hospitals to consider if biofilms are suspected to be present on materials or devices, in particular implants that have had associated infection and are considered for re-implantation. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.
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Proceedings from the 6th Annual University of Calgary Leaders in Medicine Research Symposium.
Roberts, Jodie I; Beatty, Jennifer K; Peplowski, Michael A; Keough, Michael B; Yipp, Bryan G; Hollenberg, Morley D; Beck, Paul L
2015-12-04
On November 14, 2014, the Leaders in Medicine (LIM) program at the Cumming School of Medicine, University of Calgary hosted its 6th Annual Research Symposium. Dr. Danuta Skowronski, Epidemiology Lead for Influenza and Emerging Respiratory Pathogens at the British Columbia Centre for Disease Control (BCCDC), was the keynote speaker and presented a lecture entitled "Rapid response research during emerging public health crises: influenza and reflections from the five year anniversary of the 2009 pandemic". The LIM symposium provides a forum for both LIM and non-LIM medical students to present their research work, either as an oral or poster presentation. There were a total of six oral presentations and 77 posters presented. The oral presentations included: Swathi Damaraju, "The role of cell communication and 3D Cell-Matrix environment in a stem cell-based tissue engineering strategy for bone repair"; Menglin Yang, "The proteolytic activity of Nepenthes pitcher fluid as a therapeutic for the treatment of celiac disease"; Amelia Kellar, "Monitoring pediatric inflammatory bowel disease - a retrospective analysis of transabdominal ultrasound"; Monica M. Faria-Crowder, "The design and application of a molecular profiling strategy to identify polymicrobial acute sepsis infections"; Waleed Rahmani, "Hair follicle dermal stem cells regenerate the dermal sheath, repopulate the dermal papilla and modulate hair type"; and, Laura Palmer, "A novel role for amyloid beta protein during hypoxia/ischemia". The article on the University of Calgary Leaders in Medicine Program, "A Prescription that Addresses the Decline of Basic Science Education in Medical School," in a previous issue of CIM (2014 37(5):E292) provides more details on the program. Briefly, the LIM Research Symposium has the following objectives: (1) to showcase the impressive variety of projects undertaken by students in the LIM Program as well as University of Calgary medical students; (2) to encourage medical
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Eradication of Pseudomonas aeruginosa Biofilms by Atmospheric Pressure Non-Thermal Plasma
Alkawareek, Mahmoud Y.; Algwari, Qais Th.; Laverty, Garry; Gorman, Sean P.; Graham, William G.; O'Connell, Deborah; Gilmore, Brendan F.
2012-01-01
Bacteria exist, in most environments, as complex, organised communities of sessile cells embedded within a matrix of self-produced, hydrated extracellular polymeric substances known as biofilms. Bacterial biofilms represent a ubiquitous and predominant cause of both chronic infections and infections associated with the use of indwelling medical devices such as catheters and prostheses. Such infections typically exhibit significantly enhanced tolerance to antimicrobial, biocidal and immunological challenge. This renders them difficult, sometimes impossible, to treat using conventional chemotherapeutic agents. Effective alternative approaches for prevention and eradication of biofilm associated chronic and device-associated infections are therefore urgently required. Atmospheric pressure non-thermal plasmas are gaining increasing attention as a potential approach for the eradication and control of bacterial infection and contamination. To date, however, the majority of studies have been conducted with reference to planktonic bacteria and rather less attention has been directed towards bacteria in the biofilm mode of growth. In this study, the activity of a kilohertz-driven atmospheric pressure non-thermal plasma jet, operated in a helium oxygen mixture, against Pseudomonas aeruginosa in vitro biofilms was evaluated. Pseudomonas aeruginosa biofilms exhibit marked susceptibility to exposure of the plasma jet effluent, following even relatively short (∼10′s s) exposure times. Manipulation of plasma operating conditions, for example, plasma operating frequency, had a significant effect on the bacterial inactivation rate. Survival curves exhibit a rapid decline in the number of surviving cells in the first 60 seconds followed by slower rate of cell number reduction. Excellent anti-biofilm activity of the plasma jet was also demonstrated by both confocal scanning laser microscopy and metabolism of the tetrazolium salt, XTT, a measure of bactericidal activity. PMID
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Campbell, N R; Jeffrey, P; Kiss, K; Jones, C; Anton, A R
2001-12-01
In 1995, the Calgary Fire Department developed a program to assess blood pressure in community fire stations, selected businesses and public venues. The program has gradually expanded. Currently, all 30 fire stations across Calgary, Alberta assess blood pressures for the public seven days per week throughout the year. Since 1995, there have been 10,883 measurements in 3477 people. Most people (2106) assessed had hypertensive readings, and 72 had readings greater than 220 mmHg systolic or greater than 120 mmHg diastolic, and were referred for immediate medical assessment. The program has been recently integrated into a more global vision for the prevention and control of cardiovascular disease in Calgary. Future plans include offering lipid assessments, assisting other communities to adopt the program and using the program to provide physical measures (of blood pressure, glucose, total and high density lipoprotein cholesterol, height and weight) to an ongoing questionnaire that surveys the health of Calgarians. The history of the program, its training methods, quality control, preliminary results and future plans are presented in detail to provide an example of a community-based program that could aid in the detection, monitoring and awareness of hypertension.
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Measurements of drag and flow over biofilm
NASA Astrophysics Data System (ADS)
Hartenberger, Joel; Gose, James W.; Perlin, Marc; Ceccio, Steven L.
2017-11-01
Microbial `slime' biofilms detrimentally affect the performance of every day systems from medical devices to large ocean-going vessels. In flow applications, the presence of biofilm typically results in a drag increase and may alter the turbulence in the adjacent boundary layer. Recent studies emphasize the severity of the drag penalty associated with soft biofouling and suggest potential mechanisms underlying the increase; yet, fundamental questions remain-such as the role played by compliance and the contribution of form drag to the overall resistance experienced by a fouled system. Experiments conducted on live biofilm and 3D printed rigid replicas in the Skin-Friction Flow Facility at the University of Michigan seek to examine these factors. The hydrodynamic performance of the biofilms grown on test panels was evaluated through pressure drop measurements as well as conventional and microscale PIV. High-resolution, 3D rigid replicas of select cases were generated via additive manufacturing using surface profiles obtained from a laser scanning system. Drag and flow measurements will be presented along with details of the growth process and the surface profile characterization method.
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Animal models to investigate fungal biofilm formation.
Chandra, Jyotsna; Pearlman, Eric; Ghannoum, Mahmoud A
2014-01-01
Microbial biofilms play an essential role in several infectious diseases and are defined as extensive communities of sessile organisms irreversibly associated with a surface, encased within a polysaccharide-rich extracellular matrix (ECM), and exhibiting enhanced resistance to antimicrobial drugs. Forming a biofilm provides the microbes protection from environmental stresses due to contaminants, nutritional depletion, or imbalances, but is dangerous to human health due to their inherent robustness and elevated resistance.The use of indwelling medical devices (e.g., central venous catheters, CVCs) in current therapeutic practice is associated with 80-90 % of hospital-acquired bloodstream and deep tissue infections. Most cases of catheter-related bloodstream infections (CRBSIs) involve colonization of microorganisms on catheter surfaces where they form a biofilm. Additionally, Fusarium solani and F. oxysporum were the causative organisms of the 2005/2006 outbreak of contact lens-associated fungal keratitis in the United States, Europe, the UK, and Singapore, and these infections involved formation of biofilms on contact lens. Fungal biofilm formation is studied using a number of techniques, involving the use of a wide variety of substrates and growth conditions. In vitro techniques involving the use of confocal scanning laser/scanning electron microscopy, metabolic activity assay, dry weight measurements, and antifungal susceptibility assays are increasingly used by investigators to quantify and evaluate biofilm morphology. However, there are not many in vivo models used to validate biofilm-associated infections. In this protocol, we describe a clinically relevant rabbit model of C. albicans biofilm-associated catheter infection to evaluate the morphology, topography, and architecture of fungal biofilms. We also describe a murine model of contact lens-associated Fusarium keratitis.Evaluation of the formation of fungal biofilms on catheters in vivo, their analysis
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Columbid herpesvirus-1 mortality in great horned owls (Bubo virginianus) from Calgary, Alberta
Rose, Nicole; Warren, Amy L.; Whiteside, Douglas; Bidulka, Julie; Robinson, John H.; Illanes, Oscar; Brookfield, Caroline
2012-01-01
Four cases of Columbid herpesvirus-1 infection in great horned owls (Bubo virginianus) were identified in Calgary, Alberta. Necropsy findings included severe multifocal hepatic and splenic necrosis, pharyngeal ulceration and necrosis, and gastrointestinal necrosis. Occasional eosinophilic intranuclear viral inclusion bodies were associated with the foci of necrosis and polymerase chain reaction (PCR) testing confirmed a diagnosis of herpesvirus-induced disease. The sequence of a PCR amplicon had 99.7% homology to Columbid herpesvirus-1. PMID:22942441
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ERIC Educational Resources Information Center
Baskett, H. K., Ed.; Taylor, W. H., Ed.
This publication contains addresses on continuing professional education given at a conference at the University of Calgary (Canada) in October, 1980. Themes of the conference speakers included the need for continuing professional education and the content and delivery of such education. In an opening address, J. Roby Kidd discussed the meaning of…
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Preventing microbial biofilms on catheter tubes using ultrasonic guided waves.
Wang, Huanlei; Teng, Fengmeng; Yang, Xin; Guo, Xiasheng; Tu, Juan; Zhang, Chunbing; Zhang, Dong
2017-04-04
Biofilms on indwelling tubes and medical prosthetic devices are among the leading causes of antibiotic-resistant bacterial infections. In this work, a new anti-biofilm catheter prototype was proposed. By combining an endotracheal tube (ET) with a group of ultrasonic guided wave (UGW) transducers, the general idea was to prevent bacteria aggregation with UGW vibrations. Based on quantitative analysis of UGW propagation, detailed approach was achieved through (a) selection of ultrasonic frequency, wave modes and vibration amplitude; and (b) adoption of wave coupling and 45° wave incidence technique. Performance of the proposed UGW-ET prototype was demonstrated via in vitro experiments, during which it deterred deposition of Pseudomonas aeruginosa (P. aeruginosa) biofilms successfully. With current configuration, UGW amplitudes ranged from 0.05-5 nm could be optimal to achieve biofilm prevention. This work sheds a light in the underlying mechanism of ultrasound-mediated biofilm prevention, and will inspire the development of new catheters of better antibacterial capability.
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Ashbaugh, Alyssa G.; Jiang, Xuesong; Zheng, Jesse; Tsai, Andrew S.; Kim, Woo-Shin; Thompson, John M.; Miller, Robert J.; Shahbazian, Jonathan H.; Wang, Yu; Dillen, Carly A.; Ordonez, Alvaro A.; Chang, Yong S.; Jain, Sanjay K.; Jones, Lynne C.; Sterling, Robert S.; Mao, Hai-Quan; Miller, Lloyd S.
2016-01-01
Bacterial biofilm formation is a major complication of implantable medical devices that results in therapeutically challenging chronic infections, especially in cases involving antibiotic-resistant bacteria. As an approach to prevent these infections, an electrospun composite coating comprised of poly(lactic-coglycolic acid) (PLGA) nanofibers embedded in a poly(ε-caprolactone) (PCL) film was developed to locally codeliver combinatorial antibiotics from the implant surface. The release of each antibiotic could be adjusted by loading each drug into the different polymers or by varying PLGA:PCL polymer ratios. In a mouse model of biofilm-associated orthopedic-implant infection, three different combinations of antibiotic-loaded coatings were highly effective in preventing infection of the bone/joint tissue and implant biofilm formation and were biocompatible with enhanced osseointegration. This nanofiber composite-coating technology could be used to tailor the delivery of combinatorial antimicrobial agents from various metallic implantable devices or prostheses to effectively decrease biofilm-associated infections in patients. PMID:27791154
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Novel Treatment of Staphylococcus aureus Device-Related Infections Using Fibrinolytic Agents.
Hogan, S; O'Gara, J P; O'Neill, E
2018-02-01
Staphylococcal infections involving biofilms represent a significant challenge in the treatment of patients with device-related infections. Staphylococcus aureus biofilms have been shown to be SaeRS regulated and dependent on the coagulase-catalyzed conversion of fibrinogen into fibrin on surfaces coated with human plasma. Here we investigated the treatment of staphylococcal biofilm device-related infections by digesting the fibrin biofilm matrix with and without existing antimicrobials. The fibrinolytic agents plasmin, streptokinase, and nattokinase, and TrypLE, a recombinant trypsin-like protease, were used to digest and treat S. aureus biofilms grown in vitro using in vivo -like static biofilm assays with and without antimicrobials. Cytotoxicity, the potential to induce a cytokine response in whole human blood, and the risk of induction of tolerance to fibrinolytic agents were investigated. A rat model of intravascular catheter infection was established to investigate the efficacy of selected fibrinolytic agents in vivo Under biomimetic conditions, the fibrinolytic agents effectively dispersed established S. aureus biofilms and, in combination with common antistaphylococcal antimicrobials, effectively killed bacterial cells being released from the biofilm. These fibrinolytic agents were not cytotoxic and did not affect the host immune response. The rat model of infection successfully demonstrated the activity of the selected fibrinolytic agents alone and in combination with antimicrobials on established biofilms in vivo TrypLE and nattokinase most successfully removed adherent cells from plasma-coated surfaces and significantly improved the efficacy of existing antimicrobials against S. aureus biofilms in vitro and in vivo These biofilm dispersal agents represent a viable future treatment option for S. aureus device-related infections. Copyright © 2018 American Society for Microbiology.
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Biofilm architecture in a novel pressurized biofilm reactor.
Jiang, Wei; Xia, Siqing; Duan, Liang; Hermanowicz, Slawomir W
2015-01-01
A novel pure-oxygen pressurized biofilm reactor was operated at different organic loading, mechanical shear and hydrodynamic conditions to understand the relationships between biofilm architecture and its operation. The ultimate goal was to improve the performance of the biofilm reactor. The biofilm was labeled with seven stains and observed with confocal laser scanning microscopy. Unusual biofilm architecture of a ribbon embedded between two surfaces with very few points of attachment was observed. As organic loading increased, the biofilm morphology changed from a moderately rough layer into a locally smoother biomass with significant bulging protuberances, although the chemical oxygen demand (COD) removal efficiency remained unchanged at about 75%. At higher organic loadings, biofilms contained a larger fraction of active cells distributed uniformly within a proteinaceous matrix with decreasing polysaccharide content. Higher hydrodynamic shear in combination with high organic loading resulted in the collapse of biofilm structure and a substantial decrease in reactor performance (a COD removal of 16%). Moreover, the important role of proteins for the spatial distribution of active cells was demonstrated quantitatively.
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Ganeshnarayan, Krishnaraj; Shah, Suhagi M; Libera, Matthew R; Santostefano, Anthony; Kaplan, Jeffrey B
2009-03-01
Biofilms are composed of bacterial cells encased in a self-synthesized, extracellular polymeric matrix. Poly-beta(1,6)-N-acetyl-d-glucosamine (PNAG) is a major biofilm matrix component in phylogenetically diverse bacteria. In this study we investigated the physical and chemical properties of the PNAG matrix in biofilms produced in vitro by the gram-negative porcine respiratory pathogen Actinobacillus pleuropneumoniae and the gram-positive device-associated pathogen Staphylococcus epidermidis. The effect of PNAG on bulk fluid flow was determined by measuring the rate of fluid convection through biofilms cultured in centrifugal filter devices. The rate of fluid convection was significantly higher in biofilms cultured in the presence of the PNAG-degrading enzyme dispersin B than in biofilms cultured without the enzyme, indicating that PNAG decreases bulk fluid flow. PNAG also blocked transport of the quaternary ammonium compound cetylpyridinium chloride (CPC) through the biofilms. Binding of CPC to biofilms further impeded fluid convection and blocked transport of the azo dye Allura red. Bioactive CPC was efficiently eluted from biofilms by treatment with 1 M sodium chloride. Taken together, these findings suggest that CPC reacts directly with the PNAG matrix and alters its physical and chemical properties. Our results indicate that PNAG plays an important role in controlling the physiological state of biofilms and may contribute to additional biofilm-associated processes such as biocide resistance.
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Gupta, Tripti Thapa; Karki, Surya B; Matson, Jyl S; Gehling, Daniel J; Ayan, Halim
2017-01-01
Nosocomial infections caused by opportunistic bacteria pose major healthcare problem worldwide. Out of the many microorganisms responsible for such infections, Pseudomonas aeruginosa is a ubiquitous bacterium that accounts for 10-20% of hospital-acquired infections. These infections have mortality rates ranging from 18 to 60% and the cost of treatment ranges from $20,000 to $80,000 per infection. The formation of biofilms on medical devices and implants is responsible for the majority of those infections. Only limited progress has been made to prevent this issue in a safe and cost-effective manner. To address this, we propose employing jet plasma to break down and inactivate biofilms in vitro . Moreover, to improve the antimicrobial effect on the biofilm, a treatment method using a combination of jet plasma and a biocide known as chlorhexidine (CHX) digluconate was investigated. We found that complete sterilization of P. aeruginosa biofilms can be achieved after combinatorial treatment using plasma and CHX. A decrease in biofilm viability was also observed using confocal laser scanning electron microscopy (CLSM). This treatment method sterilized biofilm-contaminated surfaces in a short treatment time, indicating it to be a potential tool for the removal of biofilms present on medical devices and implants.
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Effect of berberine on Staphylococcus epidermidis biofilm formation.
Wang, Xiaoqing; Yao, Xiao; Zhu, Zhen'an; Tang, Tingting; Dai, Kerong; Sadovskaya, Irina; Flahaut, Sigrid; Jabbouri, Said
2009-07-01
Staphylococcus epidermidis is one of the main causes of medical device-related infections owing to its adhesion and biofilm-forming abilities on biomaterial surfaces. Berberine is an isoquinoline-type alkaloid isolated from Coptidis rhizoma (huang lian in Chinese) and other herbs with many activities against various disorders. Although the inhibitory effects of berberine on planktonic bacteria have been investigated in a few studies, the capacity of berberine to inhibit biofilm formation has not been reported to date. In this study, we observed that berberine is bacteriostatic for S. epidermidis and that sub-minimal inhibitory concentrations of berberine blocked the formation of S.epidermidis biofilm. Using viability assays and berberine uptake testing, berberine at a concentration of 15-30mug/mL was shown to inhibit bacterial metabolism. Data from this study also indicated that modest concentrations of berberine (30-45mug/mL) were sufficient to exhibit an antibacterial effect and to inhibit biofilm formation significantly, as shown by the tissue culture plate (TCP) method, confocal laser scanning microscopy and scanning electron microscopy for both S. epidermidis ATCC 35984 and a clinical isolate strain SE243. Although the mechanisms of bacterial killing and inhibition of biofilm formation are not fully understood, data from this investigation indicated a potential application for berberine as an adjuvant therapeutic agent for the prevention of biofilm-related infections.
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From in vitro to in vivo Models of Bacterial Biofilm-Related Infections
Lebeaux, David; Chauhan, Ashwini; Rendueles, Olaya; Beloin, Christophe
2013-01-01
The influence of microorganisms growing as sessile communities in a large number of human infections has been extensively studied and recognized for 30–40 years, therefore warranting intense scientific and medical research. Nonetheless, mimicking the biofilm-life style of bacteria and biofilm-related infections has been an arduous task. Models used to study biofilms range from simple in vitro to complex in vivo models of tissues or device-related infections. These different models have progressively contributed to the current knowledge of biofilm physiology within the host context. While far from a complete understanding of the multiple elements controlling the dynamic interactions between the host and biofilms, we are nowadays witnessing the emergence of promising preventive or curative strategies to fight biofilm-related infections. This review undertakes a comprehensive analysis of the literature from a historic perspective commenting on the contribution of the different models and discussing future venues and new approaches that can be merged with more traditional techniques in order to model biofilm-infections and efficiently fight them. PMID:25437038
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Chauhan, Ashwini; Lebeaux, David; Ghigo, Jean-Marc
2012-01-01
Biofilms that develop on indwelling devices are a major concern in clinical settings. While removal of colonized devices remains the most frequent strategy for avoiding device-related complications, antibiotic lock therapy constitutes an adjunct therapy for catheter-related infection. However, currently used antibiotic lock solutions are not fully effective against biofilms, thus warranting a search for new antibiotic locks. Metal-binding chelators have emerged as potential adjuvants due to their dual anticoagulant/antibiofilm activities, but studies investigating their efficiency were mainly in vitro or else focused on their effects in prevention of infection. To assess the ability of such chelators to eradicate mature biofilms, we used an in vivo model of a totally implantable venous access port inserted in rats and colonized by either Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, or Pseudomonas aeruginosa. We demonstrate that use of tetrasodium EDTA (30 mg/ml) as a supplement to the gentamicin (5 mg/ml) antibiotic lock solution associated with systemic antibiotics completely eradicated Gram-positive and Gram-negative bacterial biofilms developed in totally implantable venous access ports. Gentamicin-EDTA lock was able to eliminate biofilms with a single instillation, thus reducing length of treatment. Moreover, we show that this combination was effective for immunosuppressed rats. Lastly, we demonstrate that a gentamicin-EDTA lock is able to eradicate the biofilm formed by a gentamicin-resistant strain of methicillin-resistant S. aureus. This in vivo study demonstrates the potential of EDTA as an efficient antibiotic adjuvant to eradicate catheter-associated biofilms of major bacterial pathogens and thus provides a promising new lock solution. PMID:23027191
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Influence of nanohydroxyapatite surface properties on Staphylococcus epidermidis biofilm formation.
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.
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The development and succession of bacteria were examined by 16S rRNA gene clone libraries generated from various biofilms within a metropolitan water distribution system. Biofilms were obtained from off-line devices using polycarbonate coupons from annular reactors incubated for ...
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Limitations for current production in Geobacter sulfurreducens biofilms.
Bonanni, P Sebastian; Bradley, Dan F; Schrott, Germán D; Busalmen, Juan Pablo
2013-04-01
Devices that exploit electricity produced by electroactive bacteria such as Geobacter sulfurreducens have not yet been demonstrated beyond the laboratory scale. The current densities are far from the maximum that the bacteria can produce because fundamental properties such as the mechanism of extracellular electron transport and factors limiting cell respiration remain unclear. In this work, a strategy for the investigation of electroactive biofilms is presented. Numerical modeling of the response of G. sulfurreducens biofilms cultured on a rotating disk electrode has allowed for the discrimination of different limiting steps in the process of current production within a biofilm. The model outputs reveal that extracellular electron transport limits the respiration rate of the cells furthest from the electrode to the extent that cell division is not possible. The mathematical model also demonstrates that recent findings such as the existence of a redox gradient in actively respiring biofilms can be explained by an electron hopping mechanism but not when considering metallic-like conductivities. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Kannan, Ashwin; Karumanchi, Subbalakshmi Latha; Krishna, Vinatha; Thiruvengadam, Kothai; Ramalingam, Subramaniam; Gautam, Pennathur
2014-01-01
Colonization of surfaces by bacterial cells results in the formation of biofilms. There is a need to study the factors that are important for formation of biofilms since biofilms have been implicated in the failure of semiconductor devices and implants. In the present study, the adhesion force of biofilms (formed by Pseudomonas aeruginosa) on porous silicon substrates of varying surface roughness was quantified using atomic force microscopy (AFM). The experiments were carried out to quantify the effect of surface roughness on the adhesion force of biofilm. The results show that the adhesion force increased from 1.5 ± 0.5 to 13.2 ± 0.9 nN with increase in the surface roughness of silicon substrate. The results suggest that the adhesion force of biofilm is affected by surface roughness of substrate. © 2014 Wiley Periodicals, Inc.
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Ramón-Peréz, Miriam L; Díaz-Cedillo, Francisco; Contreras-Rodríguez, Araceli; Betanzos-Cabrera, Gabriel; Peralta, Humberto; Rodríguez-Martínez, Sandra; Cancino-Diaz, Mario E; Jan-Roblero, Janet; Cancino Diaz, Juan C
2015-02-01
Biofilm formation on medical and surgical devices is the main virulence factor of Staphylococcus epidermidis. A recent study has shown that norspermidine inhibits and disassembles the biofilm in the wild-type Bacillus subtilis NCBI3610 strain. In this study, the effect of norspermidine on S. epidermidis biofilm formation of clinical or commensal strains was tested. Biofilm producing strains of S. epidermidis were isolated from healthy skin (HS; n = 3), healthy conjunctiva (HC; n = 9) and ocular infection (OI; n = 19). All strains were treated with different concentrations of norspermidine, spermidine, putrescine, and cadaverine (1, 10, 25, 50 and 100 μM), and the biofilm formation was tested on microtiter plate. Besides, cell-free supernatants of S. epidermidis growth at 4 h and 40 h were analyzed by gas chromatography coupled to mass spectrometry (GC-MS) to detect norspermidine. Results showed that norspermidine at 25 μM and 100 μM prevented the biofilm formation in 45.16% (14/31) and 16.13% (5/31), respectively; only in one isolate from OI, norspermidine did not have effect. Other polyamines as spermidine, putrescine and cadaverine did not have effect on the biofilm formation of the strains tested. Norspermidine was also capable to disassemble a biofilm already formed. Norspermidine was detected in the 40 h cell-free supernatant of S. epidermidis by GC-MS. Norspermidine inhibited the biofilm development of S. epidermidis on the surface of contact lens. In this work, it was demonstrated that S. epidermidis produces and releases norspermidine causing an inhibitory effect on biofilm formation. Moreover, this is the first time showing that clinical S. epidermidis strains have different sensitivity to norspermidine, which suggest that the composition and structure of the biofilms is varied. We propose that norspermidine could potentially be used in the pre-treating of medical and surgical devices to inhibit the biofilm formation. Copyright
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Management of Candida biofilms: state of knowledge and new options for prevention and eradication.
Bujdáková, Helena
2016-01-01
Biofilms formed by Candida species (spp.) on medical devices represent a potential health risk. The focus of current research is searching for new options for the treatment and prevention of biofilm-associated infections using different approaches including modern nanotechnology. This review summarizes current information concerning the most relevant resistance/tolerance mechanisms to conventional drugs and a role of additional factors contributing to these phenomena in Candida spp. (mostly Candida albicans). Additionally, it provides an information update in prevention and eradication of a Candida biofilm including experiences with 'lock' therapy, potential utilization of small molecules in biomedical applications, and perspectives of using photodynamic inactivation in the control of a Candida biofilm.
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Biofilm roughness determines Cryptosporidium parvum retention in environmental biofilms.
DiCesare, E A Wolyniak; Hargreaves, B R; Jellison, K L
2012-06-01
The genus Cryptosporidium is a group of waterborne protozoan parasites that have been implicated in significant outbreaks of gastrointestinal infections throughout the world. Biofilms trap these pathogens and can contaminate water supplies through subsequent release. Biofilm microbial assemblages were collected seasonally from three streams in eastern Pennsylvania and used to grow biofilms in laboratory microcosms. Daily oocyst counts in the influx and efflux flow allowed the calculation of daily oocyst retention in the biofilm. Following the removal of oocysts from the influx water, oocyst attachment to the biofilm declined to an equilibrium state within 5 days that was sustained for at least 25 days. Varying the oocyst loading rate for the system showed that biofilm retention could be saturated, suggesting that discrete binding sites determined the maximum number of oocysts retained. Oocyst retention varied seasonally but was consistent across all three sites; however, seasonal oocyst retention was not consistent across years at the same site. No correlation between oocyst attachment and any measured water quality parameter was found. However, oocyst retention was strongly correlated with biofilm surface roughness and roughness varied among seasons and across years. We hypothesize that biofilm roughness and oocyst retention are dependent on environmentally driven changes in the biofilm community rather than directly on water quality conditions. It is important to understand oocyst transport dynamics to reduce risks of human infection. Better understanding of factors controlling biofilm retention of oocysts should improve our understanding of oocyst transport at different scales.
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Da Cambra, Mark P.; McAlister, Vivian C.
2017-01-01
Summary The Canadian contribution of medical services to the British Empire during the First World War was a national endeavour. Physicians from across the country enlisted in local regiments to join. No other region provided more physicians per capita than the newly formed province of Alberta. Largely organized through the Medical School of the University of Alberta, the No. 11 Canadian Field Ambulance out of Edmonton and the No. 8 Canadian Field Ambulance out of Calgary ultimately enlisted between one-third and half of the province’s doctors to the war campaign. Many individuals from this region distinguished themselves, including LCol J.N. Gunn from Calgary, who commanded the No. 8 Canadian Field Ambulance; Maj Heber Moshier, one of the founders of the School of Pharmacy at the University of Alberta; and Dr. A.C. Rankin, who would go on to be the first Dean of Medicine at the University of Alberta. These Canadian heroes, and the many others like them who served with the No. 8 and 11 Field Ambulances, personify the sacrifice, strength and resilience of the medical community in Alberta and should not be forgotten. PMID:28930035
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Inhibition of Staphylococcus aureus biofilm by Lactobacillus isolated from fine cocoa.
Melo, Tauá Alves; Dos Santos, Thalis Ferreira; de Almeida, Milena Evangelista; Junior, Luiz Alberto Gusmão Fontes; Andrade, Ewerton Ferraz; Rezende, Rachel Passos; Marques, Lucas Miranda; Romano, Carla Cristina
2016-10-28
Biofilm production represents an important virulence and pathogenesis factor for Staphylococcus aureus. The formation of biofilms on medical devices is a major concern in hospital environments, as they can become a constant source of infection. Probiotic bacteria, such as Lactobacillus fermentum and L. plantarum, have been found to inhibit biofilm formation; however little is known about the underlying mechanism. In this study, we tested the activity of supernatants produced by L. fermentum TCUESC01 and L. plantarum TCUESC02, isolated during the fermentation of fine cocoa, against S. aureus CCMB262 biofilm production. We measured inhibition of biofilm formation in vitro and analyzed biofilm structure by confocal and electronic microscopy. Additionally, we quantified the expression of S. aureus genes icaA and icaR involved in the synthesis of the biofilm matrix by real-time PCR. Both Lactobacillus supernatants inhibited S. aureus growth. However, only L. fermentum TCUESC01 significantly reduced the thickness of the biofilm, from 14 μm to 2.83 μm (at 18 mg∙mL -1 , 90 % of the minimum inhibitory concentration, MIC), 3.12 μm (at 14 mg∙mL -1 , 70 % of the MIC), and 5.21 μm (at 10 mg∙mL -1 , 50 % of the MIC). Additionally, L. fermentum TCUESC01 supernatant modulated the expression of icaA and icaR. L. fermentum TCUESC01 reduces the formation of S. aureus biofilm under subinhibitory conditions. Inhibition of biofilm production probably depends on modulation of the ica operon.
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Wild Mushroom Extracts as Inhibitors of Bacterial Biofilm Formation
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
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The application of biofilm science to the study and control of chronic bacterial infections
Costerton, William; Veeh, Richard; Shirtliff, Mark; Pasmore, Mark; Post, Christopher; Ehrlich, Garth
2003-01-01
Unequivocal direct observations have established that the bacteria that cause device-related and other chronic infections grow in matrix-enclosed biofilms. The diagnostic and therapeutic strategies that have served us so well in the partial eradication of acute epidemic bacterial diseases have not yielded accurate data or favorable outcomes when applied to these biofilm diseases. We discuss the potential benefits of the application of the new methods and concepts developed by biofilm science and engineering to the clinical management of infectious diseases. PMID:14617746
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A short history of microbial biofilms and biofilm infections.
Høiby, Niels
2017-04-01
The observation of aggregated microbes surrounded by a self-produced matrix adhering to surfaces or located in tissues or secretions is old since both Leeuwenhoek and Pasteur have described the phenomenon. In environmental and technical microbiology, biofilms, 80-90 years ago, were already shown to be important for biofouling on submerged surfaces, for example, ships. The concept of biofilm infections and their importance in medicine was, however, initiated in the early 1970s by the observation of heaps of Pseudomonas aeruginosa cells in sputum and lung tissue from chronically infected cystic fibrosis patients. The term biofilm was introduced into medicine in 1985 by J. W. Costerton. During the following decades, the number of published biofilm articles and methods for studying biofilms increased rapidly and it was shown that adhering and nonadhering biofilm infections are widespread in medicine. The medical importance of biofilm infections is now generally accepted and guidelines for prophylaxis, diagnosis, and treatment have been published. © 2017 APMIS. Published by John Wiley & Sons Ltd.
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ERIC Educational Resources Information Center
Hannah, Kathryn
Since August of 1976, the Faculty of Nursing at the University of Calgary has developed and implemented a four-phase computer assisted instruction (CAI) project. In Phase I, the pilot project to demonstrate effectiveness of CAI as an alternative teaching strategy in that setting has been completed and replication is on-going. In Phase II,…
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Oliveira, Fernando; Lima, Cláudia Afonso; Brás, Susana; França, Ângela; Cerca, Nuno
2015-10-01
Coagulase-negative staphylococci (CoNS) are common bacterial colonizers of the human skin. They are often involved in nosocomial infections due to biofilm formation in indwelling medical devices. While biofilm formation has been extensively studied in Staphylococcus epidermidis, little is known regarding other CoNS species. Here, biofilms from six different CoNS species were characterized in terms of biofilm composition and architecture. Interestingly, the ability to form a thick biofilm was not associated with any particular species, and high variability on biofilm accumulation was found within the same species. Cell viability assays also revealed different proportions of live and dead cells within biofilms formed by different species, although this parameter was particularly similar at the intraspecies level. On the other hand, biofilm disruption assays demonstrated important inter- and intraspecies differences regarding extracellular matrix composition. Lastly, confocal laser scanning microscopy experiments confirmed this variability, highlighting important differences and common features of CoNS biofilms. We hypothesized that the biofilm formation heterogeneity observed was rather associated with biofilm matrix composition than with cells themselves. Additionally, our results indicate that polysaccharides, DNA and proteins are fundamental pieces in the process of CoNS biofilm formation. © FEMS 2015. All rights reserved.
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Effects of Material Properties on Bacterial Adhesion and Biofilm Formation.
Song, F; Koo, H; Ren, D
2015-08-01
Adhesion of microbes, such as bacteria and fungi, to surfaces and the subsequent formation of biofilms cause multidrug-tolerant infections in humans and fouling of medical devices. To address these challenges, it is important to understand how material properties affect microbe-surface interactions and engineer better nonfouling materials. Here we review the recent progresses in this field and discuss the main challenges and opportunities. In particular, we focus on bacterial biofilms and review the effects of surface energy, charge, topography, and stiffness of substratum material on bacterial adhesion. We summarize how these surface properties influence oral biofilm formation, and we discuss the important findings from nondental systems that have potential applications in dental medicine. © International & American Associations for Dental Research 2015.
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ERIC Educational Resources Information Center
Johnston, J. Cyne T.; McNeil, Deborah A.; Best, Maureen; MacLeod, Cheryl
2011-01-01
Reliable measures of growth in children are necessary for planning and evaluating obesity prevention programs. Currently, measured growth data are unavailable in Calgary for school-age children. This single sample, cross-sectional study included Grade 5 students and their parents. Height and weight measurements of 305 students (68% of those…
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Treatment of Oral Multispecies Biofilms by an Anti-Biofilm Peptide.
Wang, Zhejun; de la Fuente-Núñez, Cesar; Shen, Ya; Haapasalo, Markus; Hancock, Robert E W
2015-01-01
Human oral biofilms are multispecies microbial communities that exhibit high resistance to antimicrobial agents. Dental plaque gives rise to highly prevalent and costly biofilm-related oral infections, which lead to caries or other types of oral infections. We investigated the ability of the recently identified anti-biofilm peptide 1018 to induce killing of bacterial cells present within oral multispecies biofilms. At 10 μg/ml (6.5 μM), peptide 1018 was able to significantly (p<0.05) prevent biofilm formation over 3 days. The activity of the peptide on preformed biofilms was found to be concentration-dependent since more than 60% of the total plaque biofilm cell population was killed by 10 μg/ml of peptide 1018 in 3 days, while at 5 μg/ml 50% of cells were dead and at 1 μg/ml the peptide triggered cell death in around 30% of the total bacterial population, as revealed by confocal microscopy. The presence of saliva did not affect peptide activity, since no statistically significant difference was found in the ability of peptide 1018 to kill oral biofilms using either saliva coated and non-saliva coated hydroxyapatite surfaces. Scanning electron microscopy experiments indicated that peptide 1018 induced cell lysis in plaque biofilms. Furthermore, combined treatment using peptide 1018 and chlorhexidine (CHX) increased the anti-biofilm activity of each compound compared to when these were used alone, resulting in >50% of the biofilm being killed and >35% being dispersed in only 3 minutes. Peptide 1018 may potentially be used by itself or in combination with CHX as a non-toxic and effective anti-biofilm agent for plaque disinfection in clinical dentistry.
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Martinez, Luis R; Mihu, Mircea Radu; Tar, Moses; Cordero, Radames J B; Han, George; Friedman, Adam J; Friedman, Joel M; Nosanchuk, Joshua D
2010-05-01
Candida species are a major cause of catheter infections. Using a central venous catheter Candida albicans biofilm model, we demonstrated that chitosan, a polymer isolated from crustacean exoskeletons, inhibits candidal biofilm formation in vivo. Furthermore, chitosan statistically significantly decreased both the metabolic activity of the biofilms and the cell viability of C. albicans and Candida parapsilosis biofilms in vitro. In addition, confocal and scanning electron microscopic examination demonstrated that chitosan penetrates candidal biofilms and damages fungal cells. Importantly, the concentrations of chitosan that were used to evaluate fungal biofilm susceptibility were not toxic to human endothelial cells. Chitosan should be considered for the prevention or treatment of fungal biofilms on central venous catheters and perhaps other medical devices.
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Fong, Jiunn N C; Yildiz, Fitnat H
2015-04-01
Proteinaceous components of the biofilm matrix include secreted extracellular proteins, cell surface adhesins, and protein subunits of cell appendages such as flagella and pili. Biofilm matrix proteins play diverse roles in biofilm formation and dissolution. They are involved in attaching cells to surfaces, stabilizing the biofilm matrix via interactions with exopolysaccharide and nucleic acid components, developing three-dimensional biofilm architectures, and dissolving biofilm matrix via enzymatic degradation of polysaccharides, proteins, and nucleic acids. In this article, we will review functions of matrix proteins in a selected set of microorganisms, studies of the matrix proteomes of Vibrio cholerae and Pseudomonas aeruginosa, and roles of outer membrane vesicles and of nucleoid-binding proteins in biofilm formation.
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Biophysics of biofilm infection.
Stewart, Philip S
2014-04-01
This article examines a likely basis of the tenacity of biofilm infections that has received relatively little attention: the resistance of biofilms to mechanical clearance. One way that a biofilm infection persists is by withstanding the flow of fluid or other mechanical forces that work to wash or sweep microorganisms out of the body. The fundamental criterion for mechanical persistence is that the biofilm failure strength exceeds the external applied stress. Mechanical failure of the biofilm and release of planktonic microbial cells is also important in vivo because it can result in dissemination of infection. The fundamental criterion for detachment and dissemination is that the applied stress exceeds the biofilm failure strength. The apparent contradiction for a biofilm to both persist and disseminate is resolved by recognizing that biofilm material properties are inherently heterogeneous. There are also mechanical aspects to the ways that infectious biofilms evade leukocyte phagocytosis. The possibility of alternative therapies for treating biofilm infections that work by reducing biofilm cohesion could (1) allow prevailing hydrodynamic shear to remove biofilm, (2) increase the efficacy of designed interventions for removing biofilms, (3) enable phagocytic engulfment of softened biofilm aggregates, and (4) improve phagocyte mobility and access to biofilm. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.
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Biophysics of Biofilm Infection
Stewart, Philip S.
2014-01-01
This article examines a likely basis of the tenacity of biofilm infections that has received relatively little attention: the resistance of biofilms to mechanical clearance. One way that a biofilm infection persists is by withstanding the flow of fluid or other mechanical forces that work to wash or sweep microorganisms out of the body. The fundamental criterion for mechanical persistence is that the biofilm failure strength exceeds the external applied stress. Mechanical failure of the biofilm and release of planktonic microbial cells is also important in vivo because it can result in dissemination of infection. The fundamental criterion for detachment and dissemination is that the applied stress exceeds the biofilm failure strength. The apparent contradiction for a biofilm to both persist and disseminate is resolved by recognizing that biofilm material properties are inherently heterogeneous. There are also mechanical aspects to the ways that infectious biofilms evade leukocyte phagocytosis. The possibility of alternative therapies for treating biofilm infections that work by reducing biofilm cohesion could: 1) allow prevailing hydrodynamic shear to remove biofilm, 2) increase the efficacy of designed interventions for removing biofilms, 3) enable phagocytic engulfment of softened biofilm aggregates, and 4) improve phagocyte mobility and access to biofilm. PMID:24376149
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Bräunlich, Marie; Økstad, Ole A; Slimestad, Rune; Wangensteen, Helle; Malterud, Karl E; Barsett, Hilde
2013-12-05
Many bacteria growing on surfaces form biofilms. Adaptive and genetic changes of the microorganisms in this structure make them resistant to antimicrobial agents. Biofilm-forming organisms on medical devices can pose serious threats to human health. Thus, there is a need for novel prevention and treatment strategies. This study aimed to evaluate the ability of Aronia melanocarpa extracts, subfractions and compounds to prevent biofilm formation and to inhibit bacterial growth of Escherichia coli and Bacillus cereus in vitro. It was found that several aronia substances possessed anti-biofilm activity, however, they were not toxic to the species screened. This non-toxic inhibition may confer a lower potential for resistance development compared to conventional antimicrobials.
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Modeling microbial survival in buildup biofilm for complex medical devices
2009-01-01
Background Flexible endoscopes undergo repeated rounds of patient-use and reprocessing. Some evidence indicates that there is an accumulation or build-up of organic material that occurs over time in endoscope channels. This "buildup biofilm" (BBF) develops as a result of cyclical exposure to wet and dry phases during usage and reprocessing. This study investigated whether the BBF matrix represents a greater challenge to disinfectant efficacy and microbial eradication than traditional biofilm (TBF), which forms when a surface is constantly bathed in fluid. Methods Using the MBEC (Minimum Biofilm Eradication Concentration) system, a unique modelling approach was developed to evaluate microbial survival in BBF formed by repetitive cycles of drying, disinfectant exposure and re-exposure to the test organism. This model mimics the cumulative effect of the reprocessing protocol on flexible endoscopes. Glutaraldehyde (GLUT) and accelerated hydrogen peroxide (AHP) were evaluated to assess the killing of microbes in TBF and BBF. Results The data showed that the combination of an organic matrix and aldehyde disinfection quickly produced a protective BBF that facilitated high levels of organism survival. In cross-linked BBF formed under high nutrient conditions the maximum colony forming units (CFU) reached ~6 Log10 CFU/peg. However, if an oxidizing agent was used for disinfection and if organic levels were kept low, organism survival did not occur. A key finding was that once established, the microbial load of BBF formed by GLUT exposure had a faster rate of accumulation than in TBF. The rate of biofilm survival post high-level disinfection (HLD) determined by the maximum Log10CFU/initial Log10CFU for E. faecalis and P. aeruginosa in BBF was 10 and 8.6 respectively; significantly different compared to a survival rate in TBF of ~2 for each organism. Data from indirect outgrowth testing demonstrated for the first time that there is organism survival in the matrix. Both TBF and
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Kato, Kazuo; Tamura, Kiyomi; Nakagaki, Haruo
2012-01-01
This study was conducted to evaluate the oral biofilm-removing capacity of a dental water jet (DWJ) by measuring biofilm thickness using an electron-probe microanalyzer (EPMA). Thirty consenting subjects wore in situ plaque-generating devices, which consisted of a pair of 4mm(2) enamel slabs attached to the upper molars for 2 days. Each device removed from the mouth was clamped, and one of the slab surfaces was treated with the DWJ, irrigating it for 5s. The devices were randomly assigned to three different pressure settings of 707, 350 or 102kPa. Another slab with no treatment served as a control. Each slab was freeze-dried, sputter-coated with platinum, and examined using secondary-electron imaging. The slabs were then embedded in methacrylate and cross-sectioned in the centre. Their surfaces were polished, coated with carbon, and examined using backscattered electron compositional (COMPO) imaging. The area between the enamel and the outer biofilm surface, indicated by a thin platinum layer, was measured by COMPO imaging to calculate the average thickness of the biofilm on the specimen. The removal capacity of biofilm by irrigation was estimated using a reduced rate of biofilm thickness, which was calculated from the differences between a pair of treated and control slabs. The reduced rates were 85.5% at 707kPa, 85.1% at 350kPa and 63.4% at 102kPa, indicating that biofilm thickness was significantly reduced at every pressure setting. The results suggest that irrigation using a DWJ would be an effective means of plaque control. Copyright © 2011 Elsevier Ltd. All rights reserved.
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Donelli, G.; Francolini, I.; Romoli, D.; Guaglianone, E.; Piozzi, A.; Ragunath, C.; Kaplan, J. B.
2007-01-01
Antibiotic therapies to eradicate medical device-associated infections often fail because of the ability of sessile bacteria, encased in their exopolysaccharide matrix, to be more drug resistant than planktonic organisms. In the last two decades, several strategies to prevent microbial adhesion and biofilm formation on the surfaces of medical devices, based mainly on the use of antiadhesive, antiseptic, and antibiotic coatings on polymer surfaces, have been developed. More recent alternative approaches are based on molecules able to interfere with quorum-sensing phenomena or to dissolve biofilms. Interestingly, a newly purified β-N-acetylglucosaminidase, dispersin B, produced by the gram-negative periodontal pathogen Actinobacillus actinomycetemcomitans, is able to dissolve mature biofilms produced by Staphylococcus epidermidis as well as some other bacterial species. Therefore, in this study, we developed new polymeric matrices able to bind dispersin B either alone or in combination with an antibiotic molecule, cefamandole nafate (CEF). We showed that our functionalized polyurethanes could adsorb a significant amount of dispersin B, which was able to exert its hydrolytic activity against the exopolysaccharide matrix produced by staphylococcal strains. When microbial biofilms were exposed to both dispersin B and CEF, a synergistic action became evident, thus characterizing these polymer-dispersin B-antibiotic systems as promising, highly effective tools for preventing bacterial colonization of medical devices. PMID:17548491
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NASA Astrophysics Data System (ADS)
Yu, Wen; Hallinen, Kelsey; Wood, Kevin
Enterococcus faecalis are commonly associated with hospital acquired infections, because they readily form biofilms on instruments and medical devices. Biofilms are inherently more resistant to killing by antibiotics compared to planktonic bacteria, in part because of their heterogeneous spatial structure. Surprisingly, however, subminimal inhibitory concentrations (sub-MICs) of some antibiotics can actually promote biofilm formation. Unfortunately, much is still unknown about how low drug doses affect the composition and spatial structure of the biofilm. In this work, we investigate the effects of sub-MICs of ampicillin on the formation of E. faecalis biofilms. First, we quantified biofilm mass using crystal violet staining in polystyrene microtiter plates. We found that total biofilm mass is increased over a narrow range of ampicillin concentrations before ultimately declining at higher concentrations. Second, we show that sub-MICs of ampicillin can increase mass of E. faecalis biofilms while simultaneously increasing extracellular DNA/RNA and changing total number of viable cells under confocal microscopy. Further, we use RNA-seq to identify genes differentially expressed under sub-MICs of ampicillin. Finally, we show a mathematical model to explain this phenomenon. This work was funded by The Hartwell Foundation Individual Biomedical Research Award and NSF CAREER 1553208 to KBW.
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Lagacé, L; Jacques, M; Mafu, A A; Roy, D
2006-10-01
The susceptibility of planktonic and biofilm cells of Pseudomonas marginalis toward four commonly used biocides at different temperatures (15 and 30 degrees C) and biofilm growth times (24 and 48 h) was assessed. Using the MBEC biofilm device, biofilm production in maple sap was shown to be highly reproducible for each set of conditions tested. Biofilm formation was influenced by growth temperature and time. A temperature of 15 degrees C and incubation time of 24 h yielded fewer CFU per peg and showed fewer adhered cells and typical biofilm structures, based on scanning electron microscopy observations as compared with other conditions. Minimal biofilm eradication concentration values for P. marginalis were significantly greater (P. < 0.001) than were MBCs for planktonic cells and for every biocide tested, with the exception of minimal biofilm eradication concentration values for peracetic acid at 15 degrees C and 24 h. Sodium hypochlorite and peracetic acid sanitizers were able to eliminate P. marginalis biofilms at lower concentrations as compared with hydrogen peroxide- and quaternary ammonium-based sanitizers (P < 0.001). According to the results obtained, sodium hypochlorite and peracetic acid sanitizers would be more appropriate for maple sap collection system sanitation.
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Staphylococcus aureus biofilms: recent developments in biofilm dispersal.
Lister, Jessica L; Horswill, Alexander R
2014-01-01
Staphylococcus aureus is a major cause of nosocomial and community-acquired infections and represents a significant burden on the healthcare system. S. aureus attachment to medical implants and host tissue, and the establishment of a mature biofilm, play an important role in the persistence of chronic infections. The formation of a biofilm, and encasement of cells in a polymer-based matrix, decreases the susceptibility to antimicrobials and immune defenses, making these infections difficult to eradicate. During infection, dispersal of cells from the biofilm can result in spread to secondary sites and worsening of the infection. In this review, we discuss the current understanding of the pathways behind biofilm dispersal in S. aureus, with a focus on enzymatic and newly described broad-spectrum dispersal mechanisms. Additionally, we explore potential applications of dispersal in the treatment of biofilm-mediated infections.
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Using micro-patterned surfaces to inhibit settlement and biofilm formation by Bacillus subtilis.
Chang, Siyuan; Chen, Xiaodong; Jiang, Shuo; Chen, Jinchun; Shi, Lin
2017-07-01
Biofilm is a biological complex caused by bacteria attachment to the substrates and their subsequent reproduction and secretion. This phenomenon reduces heat transfer efficiency and causes significant losses in treated sewage heat-recovering systems. This paper describes a physical approach to inhibit bacteria settlement and biofilm formation by Bacillus subtilis, which is the dominant species in treated sewage. Here, micro-patterned surfaces with different characteristics (stripe and cube) and dimensions (1-100 μm) were fabricated as surfaces of interest. Model sewage was prepared and a rotating coupon device was used to form the biofilms. Precision balance, scanning electron microscopy, and confocal laser scanning microscopy (CLSM) were employed to investigate the inhibitory effects and the mechanisms of the biofilm-surface interactions. The results have shown that surfaces with small pattern sizes (1 and 2 μm) all reduced biofilm formation significantly. Interestingly, the CLSM images showed that the surfaces do not play a role in "killing" the bacteria. These findings are useful for future development of new process surfaces on which bacteria settlement and biofilm formation can be inhibited or minimized.
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Yang, Shoufeng; Hay, Iain D.; Cameron, David R.; Speir, Mary; Cui, Bintao; Su, Feifei; Peleg, Anton Y.; Lithgow, Trevor; Deighton, Margaret A.; Qu, Yue
2015-01-01
Biofilm formation is a major pathogenicity strategy of Staphylococcus epidermidis causing various medical-device infections. Persister cells have been implicated in treatment failure of such infections. We sought to profile bacterial subpopulations residing in S. epidermidis biofilms, and to establish persister-targeting treatment strategies to eradicate biofilms. Population analysis was performed by challenging single biofilm cells with antibiotics at increasing concentrations ranging from planktonic minimum bactericidal concentrations (MBCs) to biofilm MBCs (MBCbiofilm). Two populations of “persister cells” were observed: bacteria that survived antibiotics at MBCbiofilm for 24/48 hours were referred to as dormant cells; those selected with antibiotics at 8 X MICs for 3 hours (excluding dormant cells) were defined as tolerant-but-killable (TBK) cells. Antibiotic regimens targeting dormant cells were tested in vitro for their efficacies in eradicating persister cells and intact biofilms. This study confirmed that there are at least three subpopulations within a S. epidermidis biofilm: normal cells, dormant cells, and TBK cells. Biofilms comprise more TBK cells and dormant cells than their log-planktonic counterparts. Using antibiotic regimens targeting dormant cells, i.e. effective antibiotics at MBCbiofilm for an extended period, might eradicate S. epidermidis biofilms. Potential uses for this strategy are in antibiotic lock techniques and inhaled aerosolized antibiotics. PMID:26687035
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Resistance of non-typeable Haemophilus influenzae biofilms is independent of biofilm size
Reimche, Jennifer L.; Kirse, Daniel J.; Whigham, Amy S.; Swords, W. Edward
2016-01-01
Abstract The inflammatory middle ear disease known as otitis media can become chronic or recurrent in some cases due to failure of the antibiotic treatment to clear the bacterial etiological agent. Biofilms are known culprits of antibiotic-resistant infections; however, the mechanisms of resistance for non-typeable Haemophilus influenzae biofilms have not been completely elucidated. In this study, we utilized in vitro static biofilm assays to characterize clinical strain biofilms and addressed the hypothesis that biofilms with greater biomass and/or thickness would be more resistant to antimicrobial-mediated eradication than thinner and/or lower biomass biofilms. Consistent with previous studies, antibiotic concentrations required to eliminate biofilm bacteria tended to be drastically higher than concentrations required to kill planktonic bacteria. The size characterizations of the biofilms formed by the clinical isolates were compared to their minimum biofilm eradication concentrations for four antibiotics. This revealed no correlation between biofilm thickness or biomass and the ability to resist eradication by antibiotics. Therefore, we concluded that biofilm size does not play a role in antibiotic resistance, suggesting that reduction of antibiotic penetration may not be a significant mechanism for antibiotic resistance for this bacterial opportunist. PMID:27956464
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Marine Sponge-Derived Streptomyces sp. SBT343 Extract Inhibits Staphylococcal Biofilm Formation
Balasubramanian, Srikkanth; Othman, Eman M.; Kampik, Daniel; Stopper, Helga; Hentschel, Ute; Ziebuhr, Wilma; Oelschlaeger, Tobias A.; Abdelmohsen, Usama R.
2017-01-01
Staphylococcus epidermidis and Staphylococcus aureus are opportunistic pathogens that cause nosocomial and chronic biofilm-associated infections. Indwelling medical devices and contact lenses are ideal ecological niches for formation of staphylococcal biofilms. Bacteria within biofilms are known to display reduced susceptibilities to antimicrobials and are protected from the host immune system. High rates of acquired antibiotic resistances in staphylococci and other biofilm-forming bacteria further hamper treatment options and highlight the need for new anti-biofilm strategies. Here, we aimed to evaluate the potential of marine sponge-derived actinomycetes in inhibiting biofilm formation of several strains of S. epidermidis, S. aureus, and Pseudomonas aeruginosa. Results from in vitro biofilm-formation assays, as well as scanning electron and confocal microscopy, revealed that an organic extract derived from the marine sponge-associated bacterium Streptomyces sp. SBT343 significantly inhibited staphylococcal biofilm formation on polystyrene, glass and contact lens surfaces, without affecting bacterial growth. The extract also displayed similar antagonistic effects towards the biofilm formation of other S. epidermidis and S. aureus strains tested but had no inhibitory effects towards Pseudomonas biofilms. Interestingly the extract, at lower effective concentrations, did not exhibit cytotoxic effects on mouse fibroblast, macrophage and human corneal epithelial cell lines. Chemical analysis by High Resolution Fourier Transform Mass Spectrometry (HRMS) of the Streptomyces sp. SBT343 extract proportion revealed its chemical richness and complexity. Preliminary physico-chemical characterization of the extract highlighted the heat-stable and non-proteinaceous nature of the active component(s). The combined data suggest that the Streptomyces sp. SBT343 extract selectively inhibits staphylococcal biofilm formation without interfering with bacterial cell viability. Due to
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Biofilm development and enhanced stress resistance of a model, mixed-species community biofilm.
Lee, Kai Wei Kelvin; Periasamy, Saravanan; Mukherjee, Manisha; Xie, Chao; Kjelleberg, Staffan; Rice, Scott A
2014-04-01
Most studies of biofilm biology have taken a reductionist approach, where single-species biofilms have been extensively investigated. However, biofilms in nature mostly comprise multiple species, where interspecies interactions can shape the development, structure and function of these communities differently from biofilm populations. Hence, a reproducible mixed-species biofilm comprising Pseudomonas aeruginosa, Pseudomonas protegens and Klebsiella pneumoniae was adapted to study how interspecies interactions affect biofilm development, structure and stress responses. Each species was fluorescently tagged to determine its abundance and spatial localization within the biofilm. The mixed-species biofilm exhibited distinct structures that were not observed in comparable single-species biofilms. In addition, development of the mixed-species biofilm was delayed 1-2 days compared with the single-species biofilms. Composition and spatial organization of the mixed-species biofilm also changed along the flow cell channel, where nutrient conditions and growth rate of each species could have a part in community assembly. Intriguingly, the mixed-species biofilm was more resistant to the antimicrobials sodium dodecyl sulfate and tobramycin than the single-species biofilms. Crucially, such community level resilience was found to be a protection offered by the resistant species to the whole community rather than selection for the resistant species. In contrast, community-level resilience was not observed for mixed-species planktonic cultures. These findings suggest that community-level interactions, such as sharing of public goods, are unique to the structured biofilm community, where the members are closely associated with each other.
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NASA Astrophysics Data System (ADS)
Mack, Dietrich; Davies, Angharad P.; Harris, Llinos G.; Knobloch, Johannes K. M.; Rohde, Holger
Medical device-associated infections, most frequently caused by Staphylococcus epidermidis and Staphylococcus aureus, are of increasing importance in modern medicine. The formation of adherent, multilayered bacterial biofilms is crucial in the pathogenesis of these infections. Polysaccharide intercellular adhesin (PIA), a homoglycan of β-1,6-linked 2-acetamido-2-deoxy-d-glucopyranosyl residues, of which about 15% are non-N-acetylated, is central to biofilm accumulation in staphylococci. It transpires that polysaccharides - structurally very similar to PIA - are also key to biofilm formation in a number of other organisms including the important human pathogens Escherichia coli, Aggregatibacter (Actinobacillus) actinomycetemcomitans, Yersinia pestis, and Bordetella spp. Apparently, synthesis of PIA and related polysaccharides is a general feature important for biofilm formation in diverse bacterial genera. Current knowledge about the structure and biosynthesis of PIA and related polysaccharides is reviewed. Additionally, information on their role in pathogenesis of biomaterial-related and other type of infections and the potential use of PIA and related compounds for prevention of infection is evaluated.
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Resistance of non-typeable Haemophilus influenzae biofilms is independent of biofilm size.
Reimche, Jennifer L; Kirse, Daniel J; Whigham, Amy S; Swords, W Edward
2017-02-01
The inflammatory middle ear disease known as otitis media can become chronic or recurrent in some cases due to failure of the antibiotic treatment to clear the bacterial etiological agent. Biofilms are known culprits of antibiotic-resistant infections; however, the mechanisms of resistance for non-typeable Haemophilus influenzae biofilms have not been completely elucidated. In this study, we utilized in vitro static biofilm assays to characterize clinical strain biofilms and addressed the hypothesis that biofilms with greater biomass and/or thickness would be more resistant to antimicrobial-mediated eradication than thinner and/or lower biomass biofilms. Consistent with previous studies, antibiotic concentrations required to eliminate biofilm bacteria tended to be drastically higher than concentrations required to kill planktonic bacteria. The size characterizations of the biofilms formed by the clinical isolates were compared to their minimum biofilm eradication concentrations for four antibiotics. This revealed no correlation between biofilm thickness or biomass and the ability to resist eradication by antibiotics. Therefore, we concluded that biofilm size does not play a role in antibiotic resistance, suggesting that reduction of antibiotic penetration may not be a significant mechanism for antibiotic resistance for this bacterial opportunist. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Chen, Quan; Zhu, Zhiling; Wang, Jun; Lopez, Analette I; Li, Siheng; Kumar, Amit; Yu, Fei; Chen, Haoqing; Cai, Chengzhi; Zhang, Lijuan
2017-03-01
Bacterial interference is an alternative strategy to fight against device-associated bacterial infections. Pursuing this strategy, a non-pathogenic bacterial biofilm is used as a live, protective barrier to fence off pathogen colonization. In this work, biofilms formed by probiotic Escherichia coli strain Nissle 1917 (EcN) are investigated for their potential for long-term bacterial interference against infections associated with silicone-based urinary catheters and indwelling catheters used in the digestive system, such as feeding tubes and voice prostheses. We have shown that EcN can form stable biofilms on silicone substrates, particularly those modified with a biphenyl mannoside derivative. These biofilms greatly reduced the colonization by pathogenic Enterococcus faecalis in Lysogeny broth (LB) for 11days. Bacterial interference is an alternative strategy to fight against device-associated bacterial infections. Pursuing this strategy, we use non-pathogenic bacteria to form a biofilm that serves as a live, protective barrier against pathogen colonization. Herein, we report the first use of preformed probiotic E. coli Nissle 1917 biofilms on the mannoside-presenting silicone substrates to prevent pathogen colonization. The biofilms serve as a live, protective barrier to fence off the pathogens, whereas current antimicrobial/antifouling coatings are subjected to gradual coverage by the biomass from the rapidly growing pathogens in a high-nutrient environment. It should be noted that E. coli Nissle 1917 is commercially available and has been used in many clinical trials. We also demonstrated that this probiotic strain performed significantly better than the non-commercial, genetically modified E. coli strain that we previously reported. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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Demonstration of bacterial biofilms in culture-negative silicone stent and jones tube.
Parsa, Kami; Schaudinn, Christoph; Gorur, Amita; Sedghizadeh, Parish P; Johnson, Thomas; Tse, David T; Costerton, John W
2010-01-01
To demonstrate the presence of bacterial biofilms on a dacryocystorhinostomy silicone stent and a Jones tube. One dacryocystorhinostomy silicone stent and one Jones tube were removed from 2 patients who presented with an infection of their respective nasolacrimal system. Cultures were obtained, and the implants were processed for scanning electron microscopy and confocal laser scanning microscopy, advanced microscopic methods that are applicable for detection of uncultivable biofilm organisms. Routine bacterial cultures revealed no growth, but bacterial biofilms on outer and inner surfaces of both implants were confirmed by advanced microscopic techniques. To the authors' knowledge, this is the first article that documents the presence of biofilms on a Crawford stent or a Jones tube on patients who presented with infections involving the nasolacrimal system. Although initial cultures revealed absence of any bacterial growth, confocal laser scanning microscopy and scanning electron microscopy documented bacterial colonization. Clinicians should consider the role of biofilms and the limitation of our standard culturing techniques while treating patients with device- or implant-related infections.
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Leunisse, C; van Weissenbruch, R; Busscher, H J; van der Mei, H C; Dijk, F; Albers, F W
2001-01-01
After total laryngectomy, voice can be restored with a silicone rubber tracheoesophageal voice prosthesis. However, biofilm formation and subsequent deterioration of the silicone material of the prosthesis will limit device life by impairing valve function. To simulate the natural process of biofilm development under dynamic nutrient conditions, a modified Robbins device was used to evaluate the biofilm-related valve dysfunction of the Groningen, Provox2, Blom-Singer indwelling, and VoiceMaster voice prostheses. Obstruction of the semicircular slit-valved Groningen prosthesis leading to increased airway resistance was caused not only by a buildup of deposits on the esophageal flange and valve hat, but also by accumulation of deposits on the semicircular valve seating. The hinged flap valved Provox2 and indwelling Blom-Singer prostheses failed to close sufficiently because of biofilm formation on the valve seating. The esophageal flange of the VoiceMaster prosthesis was affected, but the tripod structure of the ball valve was fully colonized up to the titanium sleeve, which interfered with proper valve opening and closure. These findings on biofilm formation could be used for the further development and modification of critical design features of voice prostheses to facilitate tracheoesophageal speech. Copyright 2001 John Wiley & Sons, Inc.
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A new biofilm-associated colicin with increased efficiency against biofilm bacteria
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
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Mihu, Mircea Radu; Cabral, Vitor; Pattabhi, Rodney; Tar, Moses T.; Davies, Kelvin P.; Friedman, Adam J.
2016-01-01
ABSTRACT Staphylococcus aureus is frequently isolated in the setting of infections of indwelling medical devices, which are mediated by the microbe's ability to form biofilms on a variety of surfaces. Biofilm-embedded bacteria are more resistant to antimicrobial agents than their planktonic counterparts and often cause chronic infections and sepsis, particularly in patients with prolonged hospitalizations. In this study, we demonstrate that sustained nitric oxide-releasing nanoparticles (NO-np) interfere with S. aureus adhesion and prevent biofilm formation on a rat central venous catheter (CVC) model of infection. Confocal and scanning electron microscopy showed that NO-np-treated staphylococcal biofilms displayed considerably reduced thicknesses and bacterial numbers compared to those of control biofilms in vitro and in vivo, respectively. Although both phenotypes, planktonic and biofilm-associated staphylococci, of multiple clinical strains were susceptible to NO-np, bacteria within biofilms were more resistant to killing than their planktonic counterparts. Furthermore, chitosan, a biopolymer found in the exoskeleton of crustaceans and structurally integrated into the nanoparticles, seems to add considerable antimicrobial activity to the technology. Our findings suggest promising development and translational potential of NO-np for use as a prophylactic or therapeutic against bacterial biofilms on CVCs and other medical devices. PMID:27821454
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Mihu, Mircea Radu; Cabral, Vitor; Pattabhi, Rodney; Tar, Moses T; Davies, Kelvin P; Friedman, Adam J; Martinez, Luis R; Nosanchuk, Joshua D
2017-01-01
Staphylococcus aureus is frequently isolated in the setting of infections of indwelling medical devices, which are mediated by the microbe's ability to form biofilms on a variety of surfaces. Biofilm-embedded bacteria are more resistant to antimicrobial agents than their planktonic counterparts and often cause chronic infections and sepsis, particularly in patients with prolonged hospitalizations. In this study, we demonstrate that sustained nitric oxide-releasing nanoparticles (NO-np) interfere with S. aureus adhesion and prevent biofilm formation on a rat central venous catheter (CVC) model of infection. Confocal and scanning electron microscopy showed that NO-np-treated staphylococcal biofilms displayed considerably reduced thicknesses and bacterial numbers compared to those of control biofilms in vitro and in vivo, respectively. Although both phenotypes, planktonic and biofilm-associated staphylococci, of multiple clinical strains were susceptible to NO-np, bacteria within biofilms were more resistant to killing than their planktonic counterparts. Furthermore, chitosan, a biopolymer found in the exoskeleton of crustaceans and structurally integrated into the nanoparticles, seems to add considerable antimicrobial activity to the technology. Our findings suggest promising development and translational potential of NO-np for use as a prophylactic or therapeutic against bacterial biofilms on CVCs and other medical devices. Copyright © 2016 American Society for Microbiology.
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The roles of biofilm matrix polysaccharide Psl in mucoid Pseudomonas aeruginosa biofilms.
Ma, Luyan; Wang, Shiwei; Wang, Di; Parsek, Matthew R; Wozniak, Daniel J
2012-07-01
The opportunistic pathogen Pseudomonas aeruginosa causes life-threatening, persistent infections in patients with cystic fibrosis (CF). Persistence is attributed to the ability of these bacteria to form structured communities (biofilms). Biofilms rely on an extracellular polymeric substances matrix to maintain structure. Psl exopolysaccharide is a key matrix component of nonmucoid biofilms, yet the role of Psl in mucoid biofilms is unknown. In this report, using a variety of mutants in a mucoid P. aeruginosa background, we found that deletion of Psl-encoding genes dramatically decreased their biofilm formation ability, indicating that Psl is also a critical matrix component of mucoid biofilms. Our data also suggest that the overproduction of alginate leads to mucoid biofilms, which occupy more space, whereas Psl-dependent biofilms are densely packed. These data suggest that Psl polysaccharide may have significant contributions in biofilm persistence in patients with CF and may be helpful for designing therapies for P. aeruginosa CF infection. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
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Diffusion of antimicrobials in multispecies biofilms evaluated in a new biofilm model.
van der Waal, S V; de Almeida, J; Krom, B P; de Soet, J J; Crielaard, W
2017-04-01
To describe the application of a newly-developed in vitro model in which the diffusion of antimicrobials in oral biofilms can be studied. In a flow chamber consisting of three parallel feeding channels connected with each other by eight perpendicular side channels, multispecies biofilms were grown from saliva of a single donor for 48 h. The dimensions of the side channels were 100 μm × 100 μm × 5130 μm (H × W × L). When one or more side channels were filled with biofilm, the biofilms were stained with fluorescent stains. Then, one side-channel biofilm was selected and treated with phosphate buffered saline, 2% sodium hypochlorite (NaOCl), 17% ethylenediaminetetra-acetic acid (EDTA) or modified salt solution (MSS). Diffusion of the irrigants was observed by acquiring fluorescence images at 10× objective every 15 s for 30 min. It was possible to culture biofilms in the narrow (100 μm) channels. The biofilms varied in phenotype. In this model, no diffusion of NaOCl into the biofilms was seen after its application. Seventeen-percentage EDTA only diffused into the biofilm up to 200 μm in 30 min. MSS did diffuse in the biofilm over a distance of 450 μm within 2 min after a single application. This new model enables the investigation of the diffusion of antimicrobials in biofilms. Other applications to improve our understanding of the characteristics of biofilms are now possible. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.
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Ooi, N; Eady, E A; Cove, J H; O'Neill, A J
2015-02-01
To investigate the antistaphylococcal/antibiofilm activity and mode of action (MOA) of a panel of redox-active (RA) compounds with a history of human use and to provide a preliminary preclinical assessment of their potential for topical treatment of staphylococcal infections, including those involving a biofilm component. Antistaphylococcal activity was evaluated by broth microdilution and by time-kill studies with growing and slow- or non-growing cells. The antibiofilm activity of RA compounds, alone and in combination with established antibacterial agents, was assessed using the Calgary Biofilm Device. Established assays were used to examine the membrane-perturbing effects of RA compounds, to measure penetration into biofilms and physical disruption of biofilms and to assess resistance potential. A living skin equivalent model was used to assess the effects of RA compounds on human skin. All 15 RA compounds tested displayed antistaphylococcal activity against planktonic cultures (MIC 0.25-128 mg/L) and 7 eradicated staphylococcal biofilms (minimum biofilm eradication concentration 4-256 mg/L). The MOA of all compounds involved perturbation of the bacterial membrane, whilst selected compounds with antibiofilm activity caused destructuring of the biofilm matrix. The two most promising agents [celastrol and nordihydroguaiaretic acid (NDGA)] in respect of antibacterial potency and selective toxicity against bacterial membranes acted synergistically with gentamicin against biofilms, did not damage artificial skin following topical application and exhibited low resistance potential. In contrast to established antibacterial drugs, some RA compounds are capable of eradicating staphylococcal biofilms. Of these, celastrol and NDGA represent particularly attractive candidates for development as topical antistaphylococcal biofilm treatments. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.
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Chusri, S; Sompetch, K; Mukdee, S; Jansrisewangwong, S; Srichai, T; Maneenoon, K; Limsuwan, S; Voravuthikunchai, S P
2012-01-01
Development of biofilm is a key mechanism involved in Staphylococcus epidermidis virulence during device-associated infections. We aimed to investigate antibiofilm formation and mature biofilm eradication ability of ethanol and water extracts of Thai traditional herbal recipes including THR-SK004, THR-SK010, and THR-SK011 against S. epidermidis. A biofilm forming reference strain, S. epidermidis ATCC 35984 was employed as a model for searching anti-biofilm agents by MTT reduction assay. The results revealed that the ethanol extract of THR-SK004 (THR-SK004E) could inhibit the formation of S. epidermidis biofilm on polystyrene surfaces. Furthermore, treatments with the extract efficiently inhibit the biofilm formation of the pathogen on glass surfaces determined by scanning electron microscopy and crystal violet staining. In addition, THR-SK010 ethanol extract (THR-SK010E; 0.63-5 μg/mL) could decrease 30 to 40% of the biofilm development. Almost 90% of a 7-day-old staphylococcal biofilm was destroyed after treatment with THR-SK004E (250 and 500 μg/mL) and THR-SK010E (10 and 20 μg/mL) for 24 h. Therefore, our results clearly demonstrated THR-SK004E could prevent the staphylococcal biofilm development, whereas both THR-SK004E and THR-SK010E possessed remarkable eradication ability on the mature staphylococcal biofilm.
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Gil, Carmen; Solano, Cristina; Burgui, Saioa; Latasa, Cristina; García, Begoña; Toledo-Arana, Alejandro; Lasa, Iñigo; Valle, Jaione
2014-03-01
The Staphylococcus aureus biofilm mode of growth is associated with several chronic infections that are very difficult to treat due to the recalcitrant nature of biofilms to clearance by antimicrobials. Accordingly, there is an increasing interest in preventing the formation of S. aureus biofilms and developing efficient antibiofilm vaccines. Given the fact that during a biofilm-associated infection, the first primary interface between the host and the bacteria is the self-produced extracellular matrix, in this study we analyzed the potential of extracellular proteins found in the biofilm matrix to induce a protective immune response against S. aureus infections. By using proteomic approaches, we characterized the exoproteomes of exopolysaccharide-based and protein-based biofilm matrices produced by two clinical S. aureus strains. Remarkably, results showed that independently of the nature of the biofilm matrix, a common core of secreted proteins is contained in both types of exoproteomes. Intradermal administration of an exoproteome extract of an exopolysaccharide-dependent biofilm induced a humoral immune response and elicited the production of interleukin 10 (IL-10) and IL-17 in mice. Antibodies against such an extract promoted opsonophagocytosis and killing of S. aureus. Immunization with the biofilm matrix exoproteome significantly reduced the number of bacterial cells inside a biofilm and on the surrounding tissue, using an in vivo model of mesh-associated biofilm infection. Furthermore, immunized mice also showed limited organ colonization by bacteria released from the matrix at the dispersive stage of the biofilm cycle. Altogether, these data illustrate the potential of biofilm matrix exoproteins as a promising candidate multivalent vaccine against S. aureus biofilm-associated infections.
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Occurrence of Pharmaceuticals in Calgary's Wastewater and Related Surface Water.
Chen, M; Cooper, V I; Deng, J; Amatya, P L; Ambrus, D; Dong, S; Stalker, N; Nadeau-Bonilla, C; Patel, J
2015-05-01
The influents/effluents from Calgary's water resource recovery facilities and the surface water were analyzed for pharmaceuticals in the present study. The median concentrations in the effluents for the 15 targeted pharmaceuticals were within the range of 0.006 to 3.32 ppb. Although the wastewater treatment facilities were not designed to remove pharmaceuticals, this study indicates that the wastewater treatment processes are effective in removing some of the pharmaceuticals from the aqueous phase. The removal rate estimated can be 99.5% for caffeine, whereas little or no removal was observed for carbamazepine. Biodegradation, chemical degradation, and sorption could be some of the mechanisms responsible for the removal of pharmaceuticals. The drug residues in downstream surface water could be associated with incomplete removal of pharmaceuticals during the treatment process and may lead to concerns in terms of potential impacts on the aquatic ecosystem. However, this study does not indicate any immediate risks to the downstream aquatic environment.
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Rapid identification of bacterial biofilms and biofilm wound models using a multichannel nanosensor.
Li, Xiaoning; Kong, Hao; Mout, Rubul; Saha, Krishnendu; Moyano, Daniel F; Robinson, Sandra M; Rana, Subinoy; Zhang, Xinrong; Riley, Margaret A; Rotello, Vincent M
2014-12-23
Identification of infectious bacteria responsible for biofilm-associated infections is challenging due to the complex and heterogeneous biofilm matrix. To address this issue and minimize the impact of heterogeneity on biofilm identification, we developed a gold nanoparticle (AuNP)-based multichannel sensor to detect and identify biofilms based on their physicochemical properties. Our results showed that the sensor can discriminate six bacterial biofilms including two composed of uropathogenic bacteria. The capability of the sensor was further demonstrated through discrimination of biofilms in a mixed bacteria/mammalian cell in vitro wound model.
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Derlon, Nicolas; Grütter, Alexander; Brandenberger, Fabienne; Sutter, Anja; Kuhlicke, Ute; Neu, Thomas R; Morgenroth, Eberhard
2016-10-01
This study aimed at identifying how to improve the level of permeate flux stabilisation during gravity-driven membrane filtration without control of biofilm formation. The focus was therefore on understanding (i) how the different fractions of the biofilms (inorganics particles, bacterial cells, EPS matrix) influence its hydraulic resistance and (ii) how the compression of biofilms impacts its hydraulic resistance, i.e., can water head be increased to increase the level of permeate flux stabilisation. Biofilms were developed on ultrafiltration membranes at 88 and 284 cm water heads with dead-end filtration for around 50 days. A larger water head resulted in a smaller biofilm permeability (150 and 50 L m(-2) h(-1) bar(-1) for biofilms grown at 88 cm and 284 cm water head, respectively). Biofilms were mainly composed of EPS (>90% in volume). The comparison of the hydraulic resistances of biofilms to model fouling layers indicated that most of the hydraulic resistance is due to the EPS matrix. The compressibility of the biofilm was also evaluated by subjecting the biofilms to short-term (few minutes) and long-term variations of transmembrane pressures (TMP). A sudden change of TMP resulted in an instantaneous and reversible change of biofilm hydraulic resistance. A long-term change of TMP induced a slow change in the biofilm hydraulic resistance. Our results demonstrate that the response of biofilms to a TMP change has two components: an immediate variation of resistance (due to compression/relaxation) and a long-term response (linked to biofilm adaptation/growth). Our results provide relevant information about the relationship between the operating conditions in terms of TMP, the biofilm structure and composition and the resulting biofilm hydraulic resistance. These findings have practical implications for a broad range of membrane systems. Copyright © 2016 Elsevier Ltd. All rights reserved.
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NASA Astrophysics Data System (ADS)
Peng, Haidong; Mayer, Bernhard; Harris, Stuart; Krouse, H. Roy
2004-04-01
Short-term (0.5 3 d) precipitation samples were collected from January 1992 to December 2001 in Calgary, Alberta, Canada, and the stable isotope ratios of hydrogen (2H/1H) and oxygen (18O/16O) for these samples were determined. The 10-yr amount-weighted average δ2H and δ18O values of precipitation were -136.1‰ and -17.9‰, respectively. Consistent with International Atomic Energy Agency (IAEA) established practice, the following local meteoric water line (LMWL) for Calgary was derived using amount-weighted monthly average δ2H and δ18O values: δ2H = 7.68 δ18O -0.21 (r2= 0.96, n= 104). The correlation equation between δ2H and δ18O values from individual samples was found to be δ2H = 7.10 δ18O -13.64 (r2= 0.95, n= 839), which is different from the LMWL, exhibiting lower slope and intercept values. A comparison of δ2H and δ18O correlation equations with temperature during precipitation events showed a trend of decreasing slopes and intercepts with increasing temperature. Our data suggest that this is caused by incorporation of moisture derived from evaporation from water bodies and soils along the storm paths and by secondary evaporation between the cloud base and the ground during precipitation events. These processes compromise the usefulness of d-excess values as an indicator for the meteorological conditions in the maritime source regions. The δ18O temperature dependence at Calgary was found to be
0.44‰°C
1. The study shows that short-term sampling of individual precipitation events yields valuable information, which is not obtainable by the widely used monthly collection programs. -
Stewart, Elizabeth J; Ganesan, Mahesh; Younger, John G; Solomon, Michael J
2015-08-14
We demonstrate that the microstructural and mechanical properties of bacterial biofilms can be created through colloidal self-assembly of cells and polymers, and thereby link the complex material properties of biofilms to well understood colloidal and polymeric behaviors. This finding is applied to soften and disassemble staphylococcal biofilms through pH changes. Bacterial biofilms are viscoelastic, structured communities of cells encapsulated in an extracellular polymeric substance (EPS) comprised of polysaccharides, proteins, and DNA. Although the identity and abundance of EPS macromolecules are known, how these matrix materials interact with themselves and bacterial cells to generate biofilm morphology and mechanics is not understood. Here, we find that the colloidal self-assembly of Staphylococcus epidermidis RP62A cells and polysaccharides into viscoelastic biofilms is driven by thermodynamic phase instability of EPS. pH conditions that induce phase instability of chitosan produce artificial S. epidermidis biofilms whose mechanics match natural S. epidermidis biofilms. Furthermore, pH-induced solubilization of the matrix triggers disassembly in both artificial and natural S. epidermidis biofilms. This pH-induced disassembly occurs in biofilms formed by five additional staphylococcal strains, including three clinical isolates. Our findings suggest that colloidal self-assembly of cells and matrix polymers produces biofilm viscoelasticity and that biofilm control strategies can exploit this mechanism.
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Stewart, Elizabeth J.; Ganesan, Mahesh; Younger, John G.; Solomon, Michael J.
2015-01-01
We demonstrate that the microstructural and mechanical properties of bacterial biofilms can be created through colloidal self-assembly of cells and polymers, and thereby link the complex material properties of biofilms to well understood colloidal and polymeric behaviors. This finding is applied to soften and disassemble staphylococcal biofilms through pH changes. Bacterial biofilms are viscoelastic, structured communities of cells encapsulated in an extracellular polymeric substance (EPS) comprised of polysaccharides, proteins, and DNA. Although the identity and abundance of EPS macromolecules are known, how these matrix materials interact with themselves and bacterial cells to generate biofilm morphology and mechanics is not understood. Here, we find that the colloidal self-assembly of Staphylococcus epidermidis RP62A cells and polysaccharides into viscoelastic biofilms is driven by thermodynamic phase instability of EPS. pH conditions that induce phase instability of chitosan produce artificial S. epidermidis biofilms whose mechanics match natural S. epidermidis biofilms. Furthermore, pH-induced solubilization of the matrix triggers disassembly in both artificial and natural S. epidermidis biofilms. This pH-induced disassembly occurs in biofilms formed by five additional staphylococcal strains, including three clinical isolates. Our findings suggest that colloidal self-assembly of cells and matrix polymers produces biofilm viscoelasticity and that biofilm control strategies can exploit this mechanism. PMID:26272750
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Martins, Margarida; Uppuluri, Priya; Thomas, Derek P; Cleary, Ian A; Henriques, Mariana; Lopez-Ribot, José L; Oliveira, Rosário
2010-05-01
DNA has been described as a structural component of the extracellular matrix (ECM) in bacterial biofilms. In Candida albicans, there is a scarce knowledge concerning the contribution of extracellular DNA (eDNA) to biofilm matrix and overall structure. This work examined the presence and quantified the amount of eDNA in C. albicans biofilm ECM and the effect of DNase treatment and the addition of exogenous DNA on C. albicans biofilm development as indicators of a role for eDNA in biofilm development. We were able to detect the accumulation of eDNA in biofilm ECM extracted from C. albicans biofilms formed under conditions of flow, although the quantity of eDNA detected differed according to growth conditions, in particular with regards to the medium used to grow the biofilms. Experiments with C. albicans biofilms formed statically using a microtiter plate model indicated that the addition of exogenous DNA (>160 ng/ml) increases biofilm biomass and, conversely, DNase treatment (>0.03 mg/ml) decreases biofilm biomass at later time points of biofilm development. We present evidence for the role of eDNA in C. albicans biofilm structure and formation, consistent with eDNA being a key element of the ECM in mature C. albicans biofilms and playing a predominant role in biofilm structural integrity and maintenance.
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Characterization of Acinetobacter baumannii biofilm associated components
NASA Astrophysics Data System (ADS)
Brossard, Kari A.
Acinetobacter baumannii is a Gram-negative aerobic coccobaccillus that is a major cause of nosocomial infections worldwide. Infected individuals may develop pneumonia, urinary tract, wound, and other infections that are associated with the use of indwelling medical devices such as catheters and mechanical ventilation. Treatment is difficult because many A. baumannii isolates have developed multi-drug resistance and the bacterium can persist on abiotic surfaces. Persistence and resistance may be due to formation of biofilms, which leads to long-term colonization, evasion of the host immune system and resistance to treatment with antibiotics and disinfectants. While biofilms are complex multifaceted structures, two bacterial components that have been shown to be important in formation and stability are exopolysaccharides (EPS) and the biofilm-associated protein (Bap). An EPS, poly-beta-1,6-N-acetylglucosamine, PNAG, has been described for E. coli and S. epidermidis. PNAG acts as an intercellular adhesin. Production of this adhesin is dependent on the pga/icaABCD locus. We have identified a homologous locus in A. baumannii 307-0294 that is involved in production of an exopolysaccharide, recognized by an anti-PNAG antibody. We hypothesized that the A. baumannii pgaABCD locus plays a role in biofilm formation, and protection against host innate defenses and disinfectants suggesting that PNAG is a possible virulence factor for the organism. The first aim of this thesis will define the pgaABCD locus. We have previously identified Bap, a protein with similarity to those described for S. aureus and we have demonstrated that this protein is involved in maintaining the stability of biofilms on glass. We hypothesized that A. baumannii Bap plays a role in persistence and pathogenesis and is regulated by quorum sensing. In our second aim we will examine the role of Bap in attachment and biofilm formation on medically relevant surfaces and also determine if Bap is involved in
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[Investigation of biofilm formation properties of staphylococcus isolates].
Öcal, Duygu Nilüfer; Dolapçı, İştar; Karahan, Zeynep Ceren; Tekeli, Alper
2017-01-01
Biofilm production is an important virulence factor which allows staphylococci to adhere to medical devices. The principal component of biofilm is a "polysaccharide intercellular adhesin (PIA)" which is composed of a beta-1,6-N-acetylglucosamine polymer synthesized by an enzyme (N-acetylglucosamine transferase) encoded by the ica operon found on the bacterial chromosome. This operon is composed of four genes (A, B, C, and D), and a transposable element IS256. In this study, we aimed to determine the biofilm production characteristics of invasive/non-invasive staphylococcus isolates and different staphylococcus species. Biofilm production of 166 staphylococci was phenotypically investigated on Congo Red Agar (CRA); the presence of icaA, icaD and IS256 genes were investigated by polymerase chain reaction (PCR). 74 of the isolates (44.6%) were identified as methicillin resistant Staphylococcus aureus (MRSA), 25 (15.1%) as methicillin sensitive S.aureus (MSSA), 25 (37.3%) as Staphylococcus hominis, 20 (12%) as S.epidermidis, ten (15%) as Staphylococcus haemolyticus, nine (13.4%) as Staphylococcus capitis, two (3%) Staphylococcus saprophyticus and one (1.5%) as Staphylococcus warnerii. Of the MRSA strains, 52 were isolated from blood and 22 from nose; all MSSA strains were isolated from nose cultures. Coagulase-negative staphylococci (CoNS) strains were composed of invasive and non-invasive strains isolated from nose, catheter tip and blood cultures from patients with catheter. Production with CRA method was found to be statistically significant in invasive isolates (p< 0.001). It is concluded that; as the biofilm formation capacity of invasive isolates can cause refractory infections and the importance of carriage and hospital infections of these bacteria, it is important to prevent the spread of these isolates. A combination of phenotypic and genotypic tests is recommended for the investigation of biofilm formation in staphylococci. 40.3% of the CoNS isolates, and 85
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Pseudomonas fluorescens' view of the periodic table.
Workentine, Matthew L; Harrison, Joe J; Stenroos, Pernilla U; Ceri, Howard; Turner, Raymond J
2008-01-01
Growth in a biofilm modulates microbial metal susceptibility, sometimes increasing the ability of microorganisms to withstand toxic metal species by several orders of magnitude. In this study, a high-throughput metal toxicity screen was initiated with the aim of correlating biological toxicity data in planktonic and biofilm cells to the physiochemical properties of metal ions. To this end, Pseudomonas fluorescens ATCC 13525 was grown in the Calgary Biofilm Device (CBD) and biofilms and planktonic cells of this microorganism were exposed to gradient arrays of different metal ions. These arrays included 44 different metals with representative compounds that spanned every group of the periodic table (except for the halogens and noble gases). The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum biofilm eradication concentration (MBEC) values were obtained after exposing the biofilms to metal ions for 4 h. Using these values, metal ion toxicity was correlated to the following ion-specific physicochemical parameters: standard reduction-oxidation potential, electronegativity, the solubility product of the corresponding metal-sulfide complex, the Pearson softness index, electron density and the covalent index. When the ions were grouped according to outer shell electron structure, we found that heavy metal ions gave the strongest correlations to these parameters and were more toxic on average than the other classes of the ions. Correlations were different for biofilms than for planktonic cells, indicating that chemical mechanisms of metal ion toxicity differ between the two modes of growth. We suggest that biofilms can specifically counter the toxic effects of certain physicochemical parameters, which may contribute to the increased ability of biofilms to withstand metal toxicity.
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Kong, Eric F.; Tsui, Christina; Kucharíková, Sona; Andes, David
2016-01-01
ABSTRACT Biofilm-associated polymicrobial infections, particularly those involving fungi and bacteria, are responsible for significant morbidity and mortality and tend to be challenging to treat. Candida albicans and Staphylococcus aureus specifically are considered leading opportunistic fungal and bacterial pathogens, respectively, mainly due to their ability to form biofilms on catheters and indwelling medical devices. However, the impact of mixed-species biofilm growth on therapy remains largely understudied. In this study, we investigated the influence of C. albicans secreted cell wall polysaccharides on the response of S. aureus to antibacterial agents in biofilm. Results demonstrated significantly enhanced tolerance for S. aureus to drugs in the presence of C. albicans or its secreted cell wall polysaccharide material. Fluorescence confocal time-lapse microscopy revealed impairment of drug diffusion through the mixed biofilm matrix. Using C. albicans mutant strains with modulated cell wall polysaccharide expression, exogenous supplementation, and enzymatic degradation, the C. albicans-secreted β-1,3-glucan cell wall component was identified as the key matrix constituent providing the bacteria with enhanced drug tolerance. Further, antibody labeling demonstrated rapid coating of the bacteria by the C. albicans matrix material. Importantly, via its effect on the fungal biofilm matrix, the antifungal caspofungin sensitized the bacteria to the drugs. Understanding such symbiotic interactions with clinical relevance between microbial species in biofilms will greatly aid in overcoming the limitations of current therapies and in defining potential new targets for treating polymicrobial infections. PMID:27729510
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Kim, Soo-Kyoung; Park, Ha-Young; Lee, Joon-Hee
2015-04-01
Anthranilate and indole are alternative degradation products of tryptophan, depending on the bacterial species. While indole enhances the biofilm formation of Pseudomonas aeruginosa, we found that anthranilate, the tryptophan degradation product of P. aeruginosa, had an opposite effect on P. aeruginosa biofilm formation, in which anthranilate deteriorated the mushroom structure of biofilm. The anthranilate effect on biofilm formation was differentially exerted depending on the developmental stage and the presence of shear force. Anthranilate slightly accelerated the initial attachment of P. aeruginosa at the early stage of biofilm development and appeared to build more biofilm without shear force. But anthranilate weakened the biofilm structure in the late stage, deteriorating the mushroom structure of biofilms with shear force to make a flat biofilm. To investigate the interplay of anthranilate with indole in biofilm formation, biofilms were cotreated with anthranilate and indole, and the results showed that anthranilate antagonized the biofilm-enhancing effect of indole. Anthranilate was able to deteriorate the preformed biofilm. The effect of anthranilate and indole on biofilm formation was quorum sensing independent. AntR, a regulator of anthranilate-degrading metabolism was synergistically activated by cotreatment with anthranilate and indole, suggesting that indole might enhance biofilm formation by facilitating the degradation of anthranilate. Anthranilate slightly but significantly affected the cyclic diguaniylate (c-di-GMP) level and transcription of major extracellular polysaccharide (Psl, Pel, and alginate) operons. These results suggest that anthranilate may be a promising antibiofilm agent and antagonize the effect of indole on P. aeruginosa biofilm formation. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
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An Improved Medium for Growing Staphylococcus aureus Biofilm
2012-04-19
implantitis, chronic wound infections , chronic rhinosinusitis, endocarditis , and ocular infections (Archer et al., 2011). In addition, emerging evidence...causes of human bacterial infections , Staphylococcus aureus, a gram positive organism, is a ubiquitous oppor tunistic pathogen that commonly colonizes...resistant to antibiotic therapy. It has been shown that S. aureus biofilms are involved in oste omyelitis; indwelling medical device infections ; and peri
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Chusri, S.; Sompetch, K.; Mukdee, S.; Jansrisewangwong, S.; Srichai, T.; Maneenoon, K.; Limsuwan, S.; Voravuthikunchai, S. P.
2012-01-01
Development of biofilm is a key mechanism involved in Staphylococcus epidermidis virulence during device-associated infections. We aimed to investigate antibiofilm formation and mature biofilm eradication ability of ethanol and water extracts of Thai traditional herbal recipes including THR-SK004, THR-SK010, and THR-SK011 against S. epidermidis. A biofilm forming reference strain, S. epidermidis ATCC 35984 was employed as a model for searching anti-biofilm agents by MTT reduction assay. The results revealed that the ethanol extract of THR-SK004 (THR-SK004E) could inhibit the formation of S. epidermidis biofilm on polystyrene surfaces. Furthermore, treatments with the extract efficiently inhibit the biofilm formation of the pathogen on glass surfaces determined by scanning electron microscopy and crystal violet staining. In addition, THR-SK010 ethanol extract (THR-SK010E; 0.63–5 μg/mL) could decrease 30 to 40% of the biofilm development. Almost 90% of a 7-day-old staphylococcal biofilm was destroyed after treatment with THR-SK004E (250 and 500 μg/mL) and THR-SK010E (10 and 20 μg/mL) for 24 h. Therefore, our results clearly demonstrated THR-SK004E could prevent the staphylococcal biofilm development, whereas both THR-SK004E and THR-SK010E possessed remarkable eradication ability on the mature staphylococcal biofilm. PMID:22919409
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Galli, Jacopo; Calo', Lea; Meucci, Duino; Giuliani, Monica; Lucidi, Daniela; Paludetti, Gaetano; Torelli, Riccardo; Sanguinetti, Maurizio; Parrilla, Claudio
2018-05-16
The objective of the study was to compare the biofilm growing pattern and its morphological extent on silicone and a teflon-like material using a sonication process and a Scanning Electron Microscope (SEM). A prospective cohort study and a laboratory study. Otolaryngology -Head and Neck surgery Department and the Microbiology Institute. The participants included fifteen laryngectomized patients with phonatory prostheses, which were removed due to device failure, and two different kinds of phonatory prostheses from the laboratory (Provox 2 and ActiValve) that were artificially colonized by Candida albicans. Tracheo-esophageal puncture (TEP) is currently considered the gold standard for post-laryngectomy voice rehabilitation. "Leakage" represents the most common cause of substitution and is generated by biofilm colonization of the prosthesis by mixed mycotic and bacterial agents. New biomaterials have been developed that are deemed to be more resistant to the colonization of micro-organisms and material deformation. The devices showed colonization by mixed bacterial flora (Staphylococci 13%, Streptococci 9%, and H. influenzae 5%) and by yeasts (Candida albicans 12%). Moreover, we observed a different distribution of biofilm layers in Provox ActiValve (22.56%) compared to Provox 2 (56.82%) after experimental colonization by the previous isolated Candida strain. Resident microbiological species from the upper airways unavoidably colonize the polymer surfaces, and no strategies have been effective except for the manipulation of the chemical-physical properties of the device's polymer. Our study confirms that Provox ActiValve, which is made with a fluoroplastic material (teflon-like), is less subject to in vitro colonization by Candida, and thus showed a higher clinical resistance to biofilm and a longer lifespan. The sonication seems to significantly improve the knowledge of bacterial and mycotic flora in biofilm colonization. The design of a device for the daily
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Antimicrobial activity of a sodium hypochlorite/etidronic acid irrigant solution.
Arias-Moliz, Maria Teresa; Ordinola-Zapata, Ronald; Baca, Pilar; Ruiz-Linares, Matilde; Ferrer-Luque, Carmen María
2014-12-01
The aim of this study was to evaluate the antimicrobial activity of a 2.5% sodium hypochlorite (NaOCl)/9% etidronic acid (HEBP) irrigant solution on Enterococcus faecalis growing in biofilms and a dentinal tubule infection model. The antimicrobial activity of the solutions 2.5% NaOCl and 9% HEBP alone and associated was evaluated on E. faecalis biofilms grown in the Calgary biofilm model (minimum biofilm eradication concentration high-throughput device). For the dentinal tubule infection test, the percentage of dead cells in E. faecalis-infected dentinal tubules treated with the solutions for 10 minutes was measured using confocal laser scanning microscopy and the live/dead technique. Available chlorine and pH of the solutions were also measured. Distilled water was used as the control. Nonparametric tests were used to determine statistical differences. The highest viability was found in the distilled water group and the lowest in the NaOCl-treated dentin (P < .05). Both NaOCl solutions killed 100% of the E. faecalis biofilms and showed the highest antimicrobial activity inside dentinal tubules, without statistical differences between the 2 (P < .05). The HEBP isolated solution killed bacteria inside dentinal tubules but did not present any significant effect against E. faecalis biofilms. The incorporation of HEBP to NaOCl did not cause any loss of available chlorine within 60 minutes. HEBP did not interfere with the ability of NaOCl to kill E. faecalis grown in biofilms and inside dentinal tubules. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
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Bari, Md Aynul; Kindzierski, Warren B
2018-08-01
Exposure to ambient volatile organic compound (VOCs) in urban areas is of interest because of their potential chronic and acute adverse effects to public health. Limited information is available about VOC sources in urban areas in Canada. An investigation of ambient VOCs levels, their potential sources and associated risks to public health was undertaken for the urban core of Alberta's largest city (downtown Calgary) for the period 2010-2015. Twenty-four hour arithmetic and geometric mean concentrations of total VOCs were 42μg/m 3 and 39μg/m 3 , respectively and ranged from 16 to 160μg/m 3 , with winter levels about two-fold higher than summer. Alkanes (58%) were the most dominant compounds followed by halogenated VOCs (22%) and aromatics (11%). Mean and maximum 24h ambient concentrations of selected VOCs of public health concern were below chronic and acute health risk screening criteria of the United States regulatory agencies and a cancer screening benchmark used in Alberta equivalent to 1 in 100,000 lifetime risk. The Positive matrix factorization (PMF) model revealed nine VOC sources at downtown Calgary, where oil/natural gas extraction/combustion (26%), fuel combustion (20%), traffic sources including gasoline exhaust, diesel exhaust, mixed fugitive emissions (10-15%), and industrial coatings/solvents (12%) were predominant. Other sources included dry cleaning (3.3%), biogenic (3.5%) and a background source (18%). Source-specific health risk values were also estimated. Estimated cancer risks for all sources were below the Alberta cancer screening benchmark, and estimated non-cancer risks for all sources were well below a safe level. Copyright © 2018 Elsevier B.V. All rights reserved.
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Kouzel, Nadzeya; Oldewurtel, Enno R; Maier, Berenike
2015-07-01
Extracellular DNA is an important structural component of many bacterial biofilms. It is unknown, however, to which extent external DNA is used to transfer genes by means of transformation. Here, we quantified the acquisition of multidrug resistance and visualized its spread under selective and nonselective conditions in biofilms formed by Neisseria gonorrhoeae. The density and architecture of the biofilms were controlled by microstructuring the substratum for bacterial adhesion. Horizontal transfer of antibiotic resistance genes between cocultured strains, each carrying a single resistance, occurred efficiently in early biofilms. The efficiency of gene transfer was higher in early biofilms than between planktonic cells. It was strongly reduced after 24 h and independent of biofilm density. Pilin antigenic variation caused a high fraction of nonpiliated bacteria but was not responsible for the reduced gene transfer at later stages. When selective pressure was applied to dense biofilms using antibiotics at their MIC, the double-resistant bacteria did not show a significant growth advantage. In loosely connected biofilms, the spreading of double-resistant clones was prominent. We conclude that multidrug resistance readily develops in early gonococcal biofilms through horizontal gene transfer. However, selection and spreading of the multiresistant clones are heavily suppressed in dense biofilms. Biofilms are considered ideal reaction chambers for horizontal gene transfer and development of multidrug resistances. The rate at which genes are exchanged within biofilms is unknown. Here, we quantified the acquisition of double-drug resistance by gene transfer between gonococci with single resistances. At early biofilm stages, the transfer efficiency was higher than for planktonic cells but then decreased with biofilm age. The surface topography affected the architecture of the biofilm. While the efficiency of gene transfer was independent of the architecture, spreading of
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Role of environmental and antibiotic stress on Staphylococcus epidermidis biofilm microstructure.
Stewart, Elizabeth J; Satorius, Ashley E; Younger, John G; Solomon, Michael J
2013-06-11
Cellular clustering and separation of Staphylococcus epidermidis surface adherent biofilms were found to depend significantly on both antibiotic and environmental stress present during growth under steady flow. Image analysis techniques common to colloidal science were applied to image volumes acquired with high-resolution confocal laser scanning microscopy to extract spatial positions of individual bacteria in volumes of size ~30 × 30 × 15 μm(3). The local number density, cluster distribution, and radial distribution function were determined at each condition by analyzing the statistics of the bacterial spatial positions. Environmental stressors of high osmotic pressure (776 mM NaCl) and sublethal antibiotic dose (1.9 μg/mL vancomycin) decreased the average bacterial local number density 10-fold. Device-associated bacterial biofilms are frequently exposed to these environmental and antibiotic stressors while undergoing flow in the bloodstream. Characteristic density phenotypes associated with low, medium, and high local number densities were identified in unstressed S. epidermidis biofilms, while stressed biofilms contained medium- and low-density phenotypes. All biofilms exhibited clustering at length scales commensurate with cell division (~1.0 μm). However, density phenotypes differed in cellular connectivity at the scale of ~6 μm. On this scale, nearly all cells in the high- and medium-density phenotypes were connected into a single cluster with a structure characteristic of a densely packed disordered fluid. However, in the low-density phenotype, the number of clusters was greater, equal to 4% of the total number of cells, and structures were fractal in nature with d(f) =1.7 ± 0.1. The work advances the understanding of biofilm growth, informs the development of predictive models of transport and mechanical properties of biofilms, and provides a method for quantifying the kinetics of bacterial surface colonization as well as biofilm fracture and
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Evaluation of the antifungal effect of EDTA, a metal chelator agent, on Candida albicans biofilm.
Casalinuovo, I A; Sorge, R; Bonelli, G; Di Francesco, P
2017-03-01
Candida albicans biofilm is frequently found on artificial surfaces and the infections related to biofilm are difficult to eliminate, as they require the removal of artificial devices and treatment with antifungal drugs. Nowadays, fungal growth in biofilms is difficult to eradicate with conventional antifungal drugs such as fluconazole. Among chelating agents, disodium salt-Ethylene Diamine Tetraacetic Acid (EDTA) is known to have antifungal activity. In this study, we examined the in vitro activity of the EDTA and the antifungal drug fluconazole against C. albicans mature biofilm. C. albicans ATCC 20191, fluconazole-susceptible strain, was grown at an inoculum starter of 1 x 106 cells/ml for 72 h in 24-well microtiter plates and was further treated for 24 h with EDTA and/or fluconazole. Antifungal activities in biofilms were expressed as reduction in optical density (OD) determined by a 2,3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide (XTT) colorimetric assay and compared to untreated biofilms. Colorimetric readings revealed that EDTA alone (at 25 and 2.5 mM) significantly reduced fungal metabolic activity in preformed biofilms. Also, EDTA combined with fluconazole significantly reduced the growth of biofilm when compared to biofilm treated with fluconazole alone (at 25 and 2.5 µg/ml). Our data suggest that the employment of EDTA or other chemicals destabilizers of the biofilm matrix, in combination with antifungal drugs, could lead to the development of new strategies for the management of infections associated to Candida biofilm. Another relevant result of our study suggests that the initial cell concentration, probably through mechanisms of quorum sensing, affects the cellular viability during the process of biofilm formation.
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Szczuka, Ewa; Urbańska, Katarzyna; Pietryka, Marta; Kaznowski, Adam
2013-01-01
Many serious diseases caused by Staphylococcus aureus appear to be associated with biofilms. Therefore, we investigated the biofilm-forming ability of the methicillin-resistant S. aureus (MRSA) isolates collected from hospitalized patients. As many as 96 % strains had the ability to form biofilm in vitro. The majority of S. aureus strains formed biofilm in ica-dependent mechanism. However, 23 % of MRSA isolates formed biofilm in ica-independent mechanism. Half of these strains carried fnbB genes encoding surface proteins fibronectin-binding protein B involved in intercellular accumulation and biofilm development in S. aureus strains. The biofilm structures were examined via confocal laser scanning microscopy (CLSM) and three-dimensional structures were reconstructed. The images obtained in CLSM revealed that the biofilm created by ica-positive strains was different from biofilm formed by ica-negative strains. The MRSA population showed a large genetic diversity and we did not find a single clone that occurred preferentially in hospital environment. Our results demonstrated the variation in genes encoding adhesins for the host matrix proteins (elastin, laminin, collagen, fibronectin, and fibrinogen) and in the gene involved in biofilm formation (icaA) within the majority of S. aureus clones.
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Decreasing influenza impact in lodges: 1997-2000 Calgary Regional Health Authority.
McLeod, L; Lau, W W
2001-01-01
Influenza causes high morbidity and hospitalization rates in residents of seniors lodges, I causing increased pressure on emergency departments and hospital beds every winter. This quasi-experimental study assessed the prevention of influenza outbreaks and their consequences in Calgary lodges. A multidisciplinary team worked to improve communication between health professionals, increase resident and staff immunization coverage, obtain weights and creatinines prior to influenza season, and facilitate amantadine prophylaxis during influenza A outbreaks. We had an increase in standing orders for amantadine and up to 56% of residents from one lodge had documented creatinine levels. Amantadine was administered to residents within two days of outbreak notification. Influenza morbidity in lodge outbreaks decreased from a rate of 37% to 9% over the three years and hospitalization rates decreased from 9% to 1%. We recommend that other regions consider a similar approach to decreasing influenza morbidity and hospitalization in lodge residents.
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Xiang, Xiaohong; Deng, Wanyan; Liu, Minqiang; Xie, Jianping
2014-01-01
Many bacteria can develop biofilm (BF), a multicellular structure largely combining bacteria and their extracellular polymeric substances (EPS). The formation of biofilm results in an alternative existence in which microbes ensure their survival in adverse environments. Biofilm-relevant infections are more persistent, resistant to most antibiotics, and more recalcitrant to host immunity. Mycobacterium tuberculosis, the causative agent of tuberculosis, can develop biofilm, though whether M. tuberculosis can form biofilm within tuberculosis patients has yet to be determined. Here, we summarize the factors involved in the development and dispersal of mycobacterial biofilms, as well as underlying regulatory factors and inhibitors against biofilm to deepen our understanding of their development and to elucidate potential novel modes of action for future antibiotics. Key factors in biofilm formation identified as drug targets represent a novel and promising avenue for developing better antibiotics.
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Mercier, Anne; Bertaux, Joanne; Lesobre, Jérôme; Gravouil, Kevin; Verdon, Julien; Imbert, Christine; Valette, Eric; Héchard, Yann
2016-01-01
Electromagnetic field (EMF) treatment has proven to be effective against mineral scaling in water systems. Therefore, it should be assessed for the treatment of other deposits such as biofilms. In this study, a commercial device producing low-frequency EMF (1-10 kHz) was applied to a reactor fed with natural water for 45 days. The treatment promoted the concentration of microorganisms in suspension and limited the amount of sessile microorganisms in the biofilm, as determined by the measurement of total DNA, qPCR and microscopy. The structure of the bacterial community was assessed by t-RFLP and pyrosequencing analysis. The results showed that EMF treatment affected both planktonic and sessile community composition. EMFs were responsible for a shift in classes of Proteobacteria during development of the biofilm. It may be speculated that the EMF treatment affected particle solubility and/or microorganism hydration. This study indicated that EMFs modulated biofilm formation in natural water.
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Antimicrobial Tolerance in Biofilms
Stewart, Philip S.
2015-01-01
The tolerance of microorganisms in biofilms to antimicrobial agents is examined through a meta-analysis of literature data. A numerical tolerance factor comparing the rates of killing in the planktonic and biofilm states is defined to provide a quantitative basis for the analysis. Tolerance factors for biocides and antibiotics range over three orders of magnitude. This variation is not explained by taking into account the molecular weight of the agent, the chemistry of the agent, the substratum material, or the speciation of the microorganisms. Tolerance factors do depend on the areal cell density of the biofilm at the time of treatment and on the age of the biofilm as grown in a particular experimental system. This suggests that there is something that happens during biofilm maturation, either physical or physiological, that is essential for full biofilm tolerance. Experimental measurements of antimicrobial penetration times in biofilms range over orders of magnitude, with slower penetration (>12 min) observed for reactive oxidants and cationic molecules. These agents are retarded through the interaction of reaction, sorption, and diffusion. The specific physiological status of microbial cells in a biofilm contributes to antimicrobial tolerance. A conceptual framework for categorizing physiological cell states is discussed in the context of antimicrobial susceptibility. It is likely that biofilms harbor cells in multiple states simultaneously (e.g., growing, stress-adapted, dormant, inactive) and that this physiological heterogeneity is an important factor in the tolerance of the biofilm state. PMID:26185072
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2013-01-01
Background Polymicrobial infections are responsible for significant mortality and morbidity in adults and children. Staphylococcus epidermidis and Candida albicans are the most frequent combination of organisms isolated from polymicrobial infections. Vascular indwelling catheters are sites for mixed species biofilm formation and pose a significant risk for polymicrobial infections. We hypothesized that enhancement of biofilms in a mixed species environment increases patient mortality and morbidity. Results Mixed species biofilms of S. epidermidis and C. albicans were evaluated in vitro and in a subcutaneous catheter infection model in vivo. Mixed species biofilms were enhanced compared to single species biofilms of either S. epidermidis or C. albicans. A mixed species environment increased catheter infection and increased dissemination of S. epidermidis in mice. Microarrays were used to explore differential gene expression of S. epidermidis in the mixed species biofilms. In mixed species biofilms, compared to single species S. epidermidis biofilms, 2.7% of S. epidermidis genes were upregulated and 6% were down regulated. Staphylococcal autolysis repressors lrgA and lrgB were down regulated 36-fold and 27-fold respectively. The role of biofilm extracellular DNA was investigated by quantitation and by evaluating the effects of DNAse in a concentration and time dependent manner. S. epidermidis specific eDNA was increased in mixed species biofilms and further confirmed by degradation with DNAse. Conclusions Mixed-species biofilms are enhanced and associated with increased S. epidermidis-specific eDNA in vitro and greater systemic dissemination of S. epidermidis in vivo. Down regulation of the lrg operon, a repressor of autolysis, associated with increased eDNA suggests a possible role for bacterial autolysis in mixed species biofilms. Enhancement and systemic dissemination of S. epidermidis may explain adverse outcomes after clinical polymicrobial infections of S
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Pammi, Mohan; Liang, Rong; Hicks, John; Mistretta, Toni-Ann; Versalovic, James
2013-11-14
Polymicrobial infections are responsible for significant mortality and morbidity in adults and children. Staphylococcus epidermidis and Candida albicans are the most frequent combination of organisms isolated from polymicrobial infections. Vascular indwelling catheters are sites for mixed species biofilm formation and pose a significant risk for polymicrobial infections. We hypothesized that enhancement of biofilms in a mixed species environment increases patient mortality and morbidity. Mixed species biofilms of S. epidermidis and C. albicans were evaluated in vitro and in a subcutaneous catheter infection model in vivo. Mixed species biofilms were enhanced compared to single species biofilms of either S. epidermidis or C. albicans. A mixed species environment increased catheter infection and increased dissemination of S. epidermidis in mice. Microarrays were used to explore differential gene expression of S. epidermidis in the mixed species biofilms. In mixed species biofilms, compared to single species S. epidermidis biofilms, 2.7% of S. epidermidis genes were upregulated and 6% were down regulated. Staphylococcal autolysis repressors lrgA and lrgB were down regulated 36-fold and 27-fold respectively. The role of biofilm extracellular DNA was investigated by quantitation and by evaluating the effects of DNAse in a concentration and time dependent manner. S. epidermidis specific eDNA was increased in mixed species biofilms and further confirmed by degradation with DNAse. Mixed-species biofilms are enhanced and associated with increased S. epidermidis-specific eDNA in vitro and greater systemic dissemination of S. epidermidis in vivo. Down regulation of the lrg operon, a repressor of autolysis, associated with increased eDNA suggests a possible role for bacterial autolysis in mixed species biofilms. Enhancement and systemic dissemination of S. epidermidis may explain adverse outcomes after clinical polymicrobial infections of S. epidermidis and C. albicans.
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Chauhan, Ashwini; Lebeaux, David; Decante, Benoit; Kriegel, Irene; Escande, Marie-Christine; Ghigo, Jean-Marc; Beloin, Christophe
2012-01-01
Formation of resilient biofilms on medical devices colonized by pathogenic microorganisms is a major cause of health-care associated infection. While in vitro biofilm analyses led to promising anti-biofilm approaches, little is known about their translation to in vivo situations and on host contribution to the in vivo dynamics of infections on medical devices. Here we have developed an in vivo model of long-term bacterial biofilm infections in a pediatric totally implantable venous access port (TIVAP) surgically placed in adult rats. Using non-invasive and quantitative bioluminescence, we studied TIVAP contamination by clinically relevant pathogens, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis, and we demonstrated that TIVAP bacterial populations display typical biofilm phenotypes. In our study, we showed that immunocompetent rats were able to control the colonization and clear the bloodstream infection except for up to 30% that suffered systemic infection and death whereas none of the immunosuppressed rats survived the infection. Besides, we mimicked some clinically relevant TIVAP associated complications such as port-pocket infection and hematogenous route of colonization. Finally, by assessing an optimized antibiotic lock therapy, we established that our in vivo model enables to assess innovative therapeutic strategies against bacterial biofilm infections. PMID:22615964
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Vergara-Irigaray, Marta; Valle, Jaione; Merino, Nekane; Latasa, Cristina; García, Begoña; Ruiz de los Mozos, Igor; Solano, Cristina; Toledo-Arana, Alejandro; Penadés, José R.; Lasa, Iñigo
2009-01-01
Staphylococcus aureus can establish chronic infections on implanted medical devices due to its capacity to form biofilms. Analysis of the factors that assemble cells into a biofilm has revealed the occurrence of strains that produce either a polysaccharide intercellular adhesin/poly-N-acetylglucosamine (PIA/PNAG) exopolysaccharide- or a protein-dependent biofilm. Examination of the influence of matrix nature on the biofilm capacities of embedded bacteria has remained elusive, because a natural strain that readily converts between a polysaccharide- and a protein-based biofilm has not been studied. Here, we have investigated the clinical methicillin (meticillin)-resistant Staphylococcus aureus strain 132, which is able to alternate between a proteinaceous and an exopolysaccharidic biofilm matrix, depending on environmental conditions. Systematic disruption of each member of the LPXTG surface protein family identified fibronectin-binding proteins (FnBPs) as components of a proteinaceous biofilm formed in Trypticase soy broth-glucose, whereas a PIA/PNAG-dependent biofilm was produced under osmotic stress conditions. The induction of FnBP levels due to a spontaneous agr deficiency present in strain 132 and the activation of a LexA-dependent SOS response or FnBP overexpression from a multicopy plasmid enhanced biofilm development, suggesting a direct relationship between the FnBP levels and the strength of the multicellular phenotype. Scanning electron microscopy revealed that cells growing in the FnBP-mediated biofilm formed highly dense aggregates without any detectable extracellular matrix, whereas cells in a PIA/PNAG-dependent biofilm were embedded in an abundant extracellular material. Finally, studies of the contribution of each type of biofilm matrix to subcutaneous catheter colonization revealed that an FnBP mutant displayed a significantly lower capacity to develop biofilm on implanted catheters than the isogenic PIA/PNAG-deficient mutant. PMID:19581398
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Hu, Xuewei; Yang, Lei; Lai, Xinke; Yao, Qi; Chen, Kai
2017-10-03
This paper presented the influence of Al(III) on biodegradability, micromorphology, composition and functional groups characteristics of the biofilm extracellular polymeric substances (EPS) during different growth phases. The sequencing batch biofilm reactors were developed to cultivate biofilms under different Al(III) dosages. The results elucidated that Al(III) affected biofilm development adversely at the beginning of biofilm growth, but promoted the biofilm mass and improved the biofilm activity with the growth of the biofilm. The micromorphological observation indicated that Al(III) led to a reduction of the filaments and promotion of the EPS secretion in growth phases of the biofilm, also Al(III) could promote microorganisms to form larger colonies for mature biofilm. Then, the analysis of EPS contents and components suggested that Al(III) could increase the protein (PN) of tightly bound EPS (TB-EPS) which alleviated the metal toxicity inhibition on the biofilm during the initial phases of biofilm growth. The biofilm could gradually adapt to the inhibition caused by Al(III) at the biofilm maturation moment. Finally, through the Fourier transform infrared spectroscopy, it was found that Al(III) was beneficial for the proliferation and secretion of TB-EPS functional groups, especially the functional groups of protein and polysaccharides.
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NASA Astrophysics Data System (ADS)
Ge, C.; Norman, A. L.; Stenhouse, K. J.; Jansens, B.; Beamish, S.
2016-12-01
The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model created by the Air Resources Laboratory at the National Oceanic and Atmospheric Administration (NOAA) in the United States is utilized for modelling air mass back-trajectories (AMBT) for weather systems. In this study, the HYSPLIT model was used to analyze weather systems in Calgary, Alberta over an 8 year period. It was found that setting the level 1 height input of the model to examine air masses at 3000 meters above ground level (AGL) more accurately represents true back-trajectories of intense precipitation events than 500 mbar pressure. This study utilizes 3000m AMBT to analyze weather systems from 2008 to 2016 in Calgary, and classifies these events on the basis of their geographic origin. A variety of precipitation characteristics were measured, such as the concentration of insoluble components as well as anion and cation concentrations. Interpretation of storm formation, and its relationship to constituents of precipitation found to be important to droplet activation in clouds - such as insoluble components and sulfate - are explored. Particularly, this study focused on the geographic origin of large precipitation events of 15 mm and over, and whether these events had distinct attributes associated with the insoluble and sulfate components and/or formation at southern latitudes in the North Pacific.
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Otter, J A; Vickery, K; Walker, J T; deLancey Pulcini, E; Stoodley, P; Goldenberg, S D; Salkeld, J A G; Chewins, J; Yezli, S; Edgeworth, J D
2015-01-01
Microbes tend to attach to available surfaces and readily form biofilms, which is problematic in healthcare settings. Biofilms are traditionally associated with wet or damp surfaces such as indwelling medical devices and tubing on medical equipment. However, microbes can survive for extended periods in a desiccated state on dry hospital surfaces, and biofilms have recently been discovered on dry hospital surfaces. Microbes attached to surfaces and in biofilms are less susceptible to biocides, antibiotics and physical stress. Thus, surface attachment and/or biofilm formation may explain how vegetative bacteria can survive on surfaces for weeks to months (or more), interfere with attempts to recover microbes through environmental sampling, and provide a mixed bacterial population for the horizontal transfer of resistance genes. The capacity of existing detergent formulations and disinfectants to disrupt biofilms may have an important and previously unrecognized role in determining their effectiveness in the field, which should be reflected in testing standards. There is a need for further research to elucidate the nature and physiology of microbes on dry hospital surfaces, specifically the prevalence and composition of biofilms. This will inform new approaches to hospital cleaning and disinfection, including novel surfaces that reduce microbial attachment and improve microbial detachment, and methods to augment the activity of biocides against surface-attached microbes such as bacteriophages and antimicrobial peptides. Future strategies to address environmental contamination on hospital surfaces should consider the presence of microbes attached to surfaces, including biofilms. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
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Gökçen, Anke; Vilcinskas, Andreas; Wiesner, Jochen
2013-01-01
The production of extracellular poly-β-1,6-N-acetyl-d-glucosamine (PNAG) by Staphylococcus epidermidis is the principal determinant of biofilm formation on indwelling medical devices. Enzymes that degrade PNAG therefore provide an attractive strategy for biofilm removal and for the manufacture of biofilm-resistant coatings. Here we present methods that allow the identification of PNAG-degrading enzymes with the ability to detach biofilms. Our protocol includes the preparation of soluble PNAG from S. epidermidis cultures, the incubation of soluble PNAG with candidate enzymes and assays that detect the release of N-acetyl-d-glucosamine using high-pH anion-exchange chromatography (HPAEC) followed in parallel by pulsed amperometric detection (PAD) and online electrospray ionization mass spectrometry (ESI-MS). We validated our procedures using dispersin B, which is currently the only known PNAG-degrading enzyme. PMID:23357872
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Juda, Marek; Helon, Pawel; Malm, Anna
2016-11-01
Biofilm may be formed on wide variety of surfaces, including indwelling medical devices, leading to several infectious diseases, e.g., bacteremia and sepsis. The most,important pathogens related with infections associated with medical devices are coagulase-negative staphylococci, including Staphylococcus haeinolyticus - bacterial species which express quite often the multidrug resistance. The four clinical multiresistant and methicillin-resistant S. haenzolyticus were included in the present study. The evaluation of drug susceptibility was performed by using disc-diffusion method and broth microdilution method according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. The biofilm formation on the Nelaton catheter and the effect of linezolid, vancomycin, tigecycline and daptomycin on the biofilm formation and disruption of mature structure was based on the method with TTC (2,3,5-triphenyltetrazolium chloride). The adhesion process of S. haenzolyticus to the Nelaton catheter was inhibited by antibiotics, as follows: line-zolid at concentration 0.25-0.5 x MIC, vancomycin - concentration 0.5 x MIC, tigecycline - concentration 0.25-4 x MIC and daptomycin - concentration 0.06-1 x MIC, depending on the isolate. Linezolid inhibited the biofilm formation at concentration between 0.5-1 x MIC, vancomycin - 1-2 x MIC, tigecycline - 0.5-4 x MIC and daptomycin - 0.06-2 x MIC. The concentration of linezolid eradicating the mature biofilm was found to be 1-2 x MIC, vancomycin - 2-8 x MIC, tigecycline - 2-4 x MIC and daptomycin - 0.06-2 x MIC. The most active antibiotic against S. haentolyticus biofilm formation and disruption of mature structure seems to be daptomycin.
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Spatial and temporal analogies in microbial communities in natural drinking water biofilms.
Douterelo, I; Jackson, M; Solomon, C; Boxall, J
2017-03-01
Biofilms are ubiquitous throughout drinking water distribution systems (DWDS), playing central roles in system performance and delivery of safe clean drinking water. However, little is known about how the interaction of abiotic and biotic factors influence the microbial communities of these biofilms in real systems. Results are presented here from a one-year study using in situ sampling devices installed in two operational systems supplied with different source waters. Independently of the characteristics of the incoming water and marked differences in hydraulic conditions between sites and over time, a core bacterial community was observed in all samples suggesting that internal factors (autogenic) are central in shaping biofilm formation and composition. From this it is apparent that future research and management strategies need to consider the specific microorganisms found to be able to colonise pipe surfaces and form biofilms, such that it might be possible to exclude these and hence protect the supply of safe clean drinking water. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.
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ERIC Educational Resources Information Center
Liljedahl, Peter, Ed.
2007-01-01
This submission contains the Proceedings of the 2006 Annual Meeting of the Canadian Mathematics Education Study Group (CMESG), held at the University of Calgary in Calgary, Alberta. The CMESG is a group of mathematicians and mathematics educators who meet annually to discuss mathematics education issues at all levels of learning. The aims of the…
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Design and field application of a UV-LED based optical fiber biofilm sensor.
Fischer, Matthias; Wahl, Martin; Friedrichs, Gernot
2012-03-15
Detecting changes in the formation dynamics of biofilms stemming from bacteria and unicellular microorganisms in their natural environment is of prime interest for biological, ecological as well as anti-fouling technology research. We developed a robust optical fiber-based biofilm sensor ready to be applied in natural aquatic environments for on-line, in situ and non-destructive monitoring of large-area biofilms. The device is based on the detection of the natural fluorescence of microorganisms constituting the biofilm. Basically, the intrinsic fluorescence of the amino acid tryptophan is excited at a wavelength of λ=280 nm and detected at λ=350 nm utilising a numerically optimized sensor head equipped with a UV-LED light source and optical fiber bundles for efficient fluorescence light collection. Calibration was carried out with tryptophan solutions and two characteristic marine bacteria strains revealing linear signal response, satisfactory background suppression, wide dynamic range, and an experimental detection limit of 4 × 10(3)cells/cm(2). Successful field experiments in the Baltic Sea accomplished over a period of twenty-one days provided for the first time continuous observation of biofilm formation dynamics in a natural habitat. Starting from the first adhering bacteria, the measurement yielded the characteristic three phases of biofilm formation up to a fully developed biofilm. The sensor system holds potential for applications in aquatic sciences including deep sea research and, after further miniaturisation, in the industrial and biomedical field. Copyright © 2012 Elsevier B.V. All rights reserved.
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Biofilm in endodontics: A review
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
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Gaining Insights from Candida Biofilm Heterogeneity: One Size Does Not Fit All
Kean, Ryan; Delaney, Christopher; Rajendran, Ranjith; Sherry, Leighann; Metcalfe, Rebecca; Thomas, Rachael; McLean, William; Williams, Craig; Ramage, Gordon
2018-01-01
Despite their clinical significance and substantial human health burden, fungal infections remain relatively under-appreciated. The widespread overuse of antibiotics and the increasing requirement for indwelling medical devices provides an opportunistic potential for the overgrowth and colonization of pathogenic Candida species on both biological and inert substrates. Indeed, it is now widely recognized that biofilms are a highly important part of their virulence repertoire. Candida albicans is regarded as the primary fungal biofilm forming species, yet there is also increasing interest and growing body of evidence for non-Candida albicans species (NCAS) biofilms, and interkingdom biofilm interactions. C. albicans biofilms are heterogeneous structures by definition, existing as three-dimensional populations of yeast, pseudo-hyphae, and hyphae, embedded within a self-produced extracellular matrix. Classical molecular approaches, driven by extensive studies of laboratory strains and mutants, have enhanced our knowledge and understanding of how these complex communities develop, thrive, and cause host-mediated damage. Yet our clinical observations tell a different story, with differential patient responses potentially due to inherent biological heterogeneity from specific clinical isolates associated with their infections. This review explores some of the recent advances made in an attempt to explore the importance of working with clinical isolates, and what this has taught us. PMID:29371505
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Cerca, Nuno; Gomes, Fernanda; Pereira, Sofia; Teixeira, Pilar; Oliveira, Rosário
2012-05-16
Staphylococcus epidermidis is the major bacterial species found in biofilm-related infections on indwelling medical devices. Microbial biofilms are communities of bacteria adhered to a surface and surrounded by an extracellular polymeric matrix. Biofilms have been associated with increased antibiotic tolerance to the immune system. This increased resistance to conventional antibiotic therapy has lead to the search for new antimicrobial therapeutical agents. Farnesol, a quorum-sensing molecule in Candida albicans, has been described as impairing growth of several different microorganisms and we have previously shown its potential as an adjuvant in antimicrobial therapy against S. epidermidis. However, its mechanism of action in S. epidermidis is not fully known. In this work we better elucidate the role of farnesol against S: epidermidis biofilms using confocal laser scanning microscopy (CLSM). 24 h biofilms were exposed to farnesol, vancomycin or rifampicin and were analysed by CLSM, after stained with a Live/Dead stain, a known indicator of cell viability, related with cell membrane integrity. Biofilms were also disrupted by sonication and viable and cultivable cells were quantified by colony forming units (CFU) plating. Farnesol showed a similar effect as vancomycin, both causing little reduction of cell viability but at the same time inducing significant changes in the biofilm structure. On the other hand, rifampicin showed a distinct action in S. epidermidis biofilms, by killing a significant proportion of biofilm bacteria. While farnesol is not very efficient at killing biofilm bacteria, it damages cell membrane, as determined by the live/dead staining, in a similar way as vancomycin. Furthermore, farnesol might induce biofilm detachment, as determined by the reduced biofilm biomass, which can partially explain the previous findings regarding its role as a possible chemotherapy adjuvant.
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Büttner, Henning; Mack, Dietrich; Rohde, Holger
2015-01-01
Staphylococcus epidermidis is a usually harmless commensal bacterium highly abundant on the human skin. Under defined predisposing conditions, most importantly implantation of a medical device, S. epidermidis, however, can switch from a colonizing to an invasive life style. The emergence of S. epidermidis as an opportunistic pathogen is closely linked to the biofilm forming capability of the species. During the past decades, tremendous advance regarding our understanding of molecular mechanisms contributing to surface colonization has been made, and detailed information is available for several factors active during the primary attachment, accumulative or dispersal phase of biofilm formation. A picture evolved in which distinct factors, though appearing to be redundantly organized, take over specific and exclusive functions during biofilm development. In this review, these mechanisms are described in molecular detail, with a highlight on recent insights into multi-functional S. epidermidis cell surface proteins contributing to surface adherence and intercellular adhesion. The integration of distinct biofilm-promoting factors into regulatory networks is summarized, with an emphasis on mechanism that could allow S. epidermidis to flexibly adapt to changing environmental conditions present during colonizing or invasive life-styles. PMID:25741476
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Harper, David R.; Parracho, Helena M. R. T.; Walker, James; Sharp, Richard; Hughes, Gavin; Werthén, Maria; Lehman, Susan; Morales, Sandra
2014-01-01
Biofilms are an extremely common adaptation, allowing bacteria to colonize hostile environments. They present unique problems for antibiotics and biocides, both due to the nature of the extracellular matrix and to the presence within the biofilm of metabolically inactive persister cells. Such chemicals can be highly effective against planktonic bacterial cells, while being essentially ineffective against biofilms. By contrast, bacteriophages seem to have a greater ability to target this common form of bacterial growth. The high numbers of bacteria present within biofilms actually facilitate the action of bacteriophages by allowing rapid and efficient infection of the host and consequent amplification of the bacteriophage. Bacteriophages also have a number of properties that make biofilms susceptible to their action. They are known to produce (or to be able to induce) enzymes that degrade the extracellular matrix. They are also able to infect persister cells, remaining dormant within them, but re-activating when they become metabolically active. Some cultured biofilms also seem better able to support the replication of bacteriophages than comparable planktonic systems. It is perhaps unsurprising that bacteriophages, as the natural predators of bacteria, have the ability to target this common form of bacterial life.
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Obaid, Najla A; Tristram, Stephen; Narkowicz, Christian K; Jacobson, Glenn A
2016-12-01
Information is lacking regarding the precision of microtitre plate (MTP) assays used to measure biofilm. This study investigated the precision of an MTP assay to measure biofilm production by nontypeable Haemophilus influenzae (NTHi) and the effects of frozen storage and inoculation technique on biofilm production. The density of bacterial final growth was determined by absorbance after 18-20 h incubation, and biofilm production was then measured by absorbance after crystal violet staining. Biofilm formation was categorised as high and low for each strain. For the high biofilm producing strains of NTHi, interday reproducibility of NTHi biofilm formation measured using the MTP assay was excellent and met the acceptance criteria, but higher variability was observed in low biofilm producers. Method of inoculum preparation was a determinant of biofilm formation with inoculum prepared directly from solid media showing increased biofilm production for at least one of the high producing strains. In general, storage of NTHi cultures at -80 °C for up to 48 weeks did not have any major effect on their ability to produce biofilm.
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Silveira, Luiz Fernando Machado; Baca, Pilar; Arias-Moliz, María Teresa; Rodríguez-Archilla, Alberto; Ferrer-Luque, Carmen María
2013-01-01
The purpose of this study was to assess the efficacy of alexidine (ALX), alone and combined with N-acetylcysteine (NAC), in eradicating two Enterococcus faecalis strain biofilms. The biofilms of E. faecalis ATCC 29212 and the clinical isolate E. faecalis D1 were grown in the MBEC-high-throughput device for 24 h and were exposed to five twofold dilutions of ALX (2%–0.007 8%) alone and combined with 100 mg⋅mL−1 NAC, for 1 and 5 min. Eradication was defined as 100% kill of biofilm bacteria. The Student's t-test was used to compare the efficacy of the associations of the two irrigants. After 1-min contact time, ALX eradicated the biofilms at all concentrations except for 0.007 8% and 0.015 6%–0.007 8% with E. faecalis ATCC 29212 and E. faecalis D1, respectively. Similar results for eradication and concentration were obtained when it was combined with 100 mg⋅mL−1 NAC. After 5 min of contact time, ALX alone and combined with NAC eradicated all enterococci biofilms. ALX showed antimicrobial properties against the two E. faecalis strain biofilms tested at very low concentrations, and its combined use with NAC was not seen to enhance its activity. PMID:23970139
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Wang, Jinfeng; Ding, Lili; Li, Kan; Huang, Hui; Hu, Haidong; Geng, Jinju; Xu, Ke; Ren, Hongqiang
2018-01-15
Quorum sensing (QS) signaling, plays a significant role in regulating formation of biofilms in the nature; however, little information about the occurrence and distribution of quorum sensing molecular in the biofilm of carriers has been reported. In this study, distribution of QS signaling molecules (the acylated homoserine lactones-AHLs, and AI-2), extracellular polymeric substances (EPS) and the mechanical properties in sequencing batch biofilm reactor (SBBR) biofilms have been investigated. Using increased centrifugal force, the biofilms were detached into different fractions. The AHLs ranged from 5.2ng/g to 98.3ng/g in different fractions of biofilms, and N-decanoyl-dl-homoserine lactone (C10-HSL) and N-dodecanoyl-dl-homoserine lactone (C12-HSL) in the biofilms obtained at various centrifugal forces displayed significant differences (p<0.01). Interspecies communication signal autoinducer-2(AI-2) in the biofilms ranged from 79.2ng/g to 98.3ng/g. Soluble EPS and loosely bound EPS content in the different fractions of biofilms displayed significant positive relationship with the distribution of C12-HSL (r=0.86, p<0.05). Furthermore, 49.62% of bacteria in the biofilms were positively related with AHLs with 22.76% was significantly positively (p<0.05) related with AHLs. Biofilm adhesion and compliance was the strongest in the tightly-bound biofilm, the weakest in the supernatant/surface biofilm, which was in accordance with the distribution of C12 HSL(r=0.77, p<0.05) and C10-HSL(r=0.75, p<0.05), respectively. This study addressed on better understanding of possible methods for the improvement of wastewater bio-treatment through biofilm application. Copyright © 2017 Elsevier B.V. All rights reserved.
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Gomez-Carretero, Salvador; Nybom, Rolf; Richter-Dahlfors, Agneta
2017-10-01
The incidence of hospital-acquired infections is to a large extent due to device-associated infections. Bacterial attachment and biofilm formation on surfaces of medical devices often act as seeding points of infection. To prevent such infections, coatings based on silver nanoparticles (AgNPs) are often applied, however with varying clinical success. Here, the traditional AgNP-based antibacterial technology is reimagined, now forming the base for an electroenhanced antimicrobial coating. To integrate AgNPs in an electrically conducting polymer layer, a simple, yet effective chemical strategy based on poly(hydroxymethyl 3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT-MeOH:PSS) and (3-aminopropyl)triethoxysilane is designed. The resultant PEDOT-MeOH:PSS-AgNP composite presents a consistent coating of covalently linked AgNPs, as shown by scanning electron microscopy and surface plasmon resonance analysis. The efficacy of the coatings, with and without electrical addressing, is then tested against Staphylococcus aureus, a major colonizer of medical implants. Using custom-designed culturing devices, a nearly complete prevention of biofilm growth is obtained in AgNP composite devices addressed with a square wave voltage input. It is concluded that this electroenhancement of the bactericidal effect of the coupled AgNPs offers a novel, efficient solution against biofilm colonization of medical implants. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Microbial Biofilms and Chronic Wounds
Omar, Amin; Wright, J. Barry; Schultz, Gregory; Burrell, Robert; Nadworny, Patricia
2017-01-01
Background is provided on biofilms, including their formation, tolerance mechanisms, structure, and morphology within the context of chronic wounds. The features of biofilms in chronic wounds are discussed in detail, as is the impact of biofilm on wound chronicity. Difficulties associated with the use of standard susceptibility tests (minimum inhibitory concentrations or MICs) to determine appropriate treatment regimens for, or develop new treatments for use in, chronic wounds are discussed, with alternate test methods specific to biofilms being recommended. Animal models appropriate for evaluating biofilm treatments are also described. Current and potential future therapies for treatment of biofilm-containing chronic wounds, including probiotic therapy, virulence attenuation, biofilm phenotype expression attenuation, immune response suppression, and aggressive debridement combined with antimicrobial dressings, are described. PMID:28272369
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Khan, Faidad; Wu, Xueqing; Matzkin, Gideon L; Khan, Mohsin A; Sakai, Fuminori; Vidal, Jorge E
2016-01-01
Staphylococcus aureus (Sau) strains are a main cause of disease, including nosocomial infections which have been linked to the production of biofilms and the propagation of antibiotic resistance strains such as methicillin-resistant Staphylococcus aureus (MRSA). A previous study found that Streptococcus pneumoniae (Spn) strains kill planktonic cultures of Sau strains. In this work, we have further evaluated in detail the eradication of Sau biofilms and investigated ultrastructural interactions of the biofilmicidal effect. Spn strain D39, which produces the competence stimulating peptide 1 (CSP1), reduced Sau biofilms within 8 h of inoculation, while TIGR4, producing CSP2, eradicated Sau biofilms and planktonic cells within 4 h. Differences were not attributed to pherotypes as other Spn strains producing different pheromones eradicated Sau within 4 h. Experiments using Transwell devices, which physically separated both species growing in the same well, demonstrated that direct contact between Spn and Sau was required to efficiently eradicate Sau biofilms and biofilm-released planktonic cells. Physical contact-mediated killing of Sau was not related to production of hydrogen peroxide as an isogenic TIGR4Δ spx B mutant eradicated Sau bacteria within 4 h. Confocal micrographs confirmed eradication of Sau biofilms by TIGR4 and allowed us to visualize ultrastructural point of contacts between Sau and Spn. A time-course study further demonstrated spatial colocalization of Spn chains and Sau tetrads as early as 30 min post-inoculation (Pearson's coefficient >0.72). Finally, precolonized biofilms produced by Sau strain Newman, or MRSA strain USA300, were eradicated by mid-log phase cultures of washed TIGR4 bacteria within 2 h post-inoculation. In conclusion, Spn strains rapidly eradicate pre-colonized Sau aureus biofilms, including those formed by MRSA strains, by a mechanism(s) requiring bacterium-bacterium contact, but independent from the production of hydrogen peroxide.
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Biofilm-related infections in ophthalmology.
Elder, M J; Stapleton, F; Evans, E; Dart, J K
1995-01-01
A biofilm is a functional consortium of microorganisms organised within an extensive exopolymer matrix. Organisms within a biofilm are difficult to eradicate by conventional antimicrobial therapy and can cause indolent infections. This paper reviews the pathophysiology of biofilms and their application of ophthalmology. Under certain environmental conditions such as nutrient limitation, some bacteria may secrete and reside in an exopolysaccharide glycocalyx polymer. This confers relative protection from humoral and cellular immunity, antibiotics and surfactants. Biofilms occur in natural aquatic ecosystems, on ship hulls, in pipelines and on the surface of biomaterials. They cause clinical infections of prosthetic hip joints, heart valves and catheters. Biofilm formation may occur rapidly on contact lenses and their cases and hence contribute to the pathogenesis of keratitis. Formation of biofilms is also implicated in delayed post-operative endophthalmitis and crystalline keratopathy. Bacteria within biofilms are 20-1000 times less sensitive to antibiotic than free-living planktonic organisms. Existing experimental methods for modifying biofilm include the use of macrolide antibiotics that specifically impair biofilm production, and the use of enzymes to digest it. These may have clinical applications, as potential adjunctive therapies to antibiotic treatment, for these resistant infections. In conclusion, biofilm is an important cause of infections associated with biomaterials. Novel strategies are needed to deal with these.
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Drago, Lorenzo; Del Fabbro, Massimo; Bortolin, Monica; Vassena, Christian; De Vecchi, Elena; Taschieri, Silvio
2014-11-01
Biofilm removal plays a central role in the prevention of periodontal and peri-implant diseases associated with microbial infections. Plaque debridement may be accomplished by air polishing using abrasive powders. In this study, a new formulation consisting of erythritol and chlorhexidine is compared with the standard glycine powder used in air-polishing devices. Their in vitro antimicrobial and antibiofilm effects on Staphylococcus aureus, Bacteroides fragilis, and Candida albicans are investigated. Biofilm was allowed to grow on sandblasted titanium disks and air polished with glycine or erythritol-chlorhexidine powders. A semiquantitative analysis of biofilm by spectrophotometric assay was performed. A qualitative analysis was also carried out by confocal laser scanning microscopy. Minimum inhibitory concentrations and minimum microbicidal concentrations were evaluated, together with the microbial recovery from the residual biofilm after air-polishing treatment. The combination of erythritol and chlorhexidine displayed stronger antimicrobial and antibiofilm activity than glycine against all microbial strains tested. Air polishing with erythritol-chlorhexidine seems to be a viable alternative to the traditional glycine treatment for biofilm removal.
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Biswas, Kristi; Taylor, Michael W; Turner, Susan J
2014-02-01
Biofilm-based technologies, such as moving bed biofilm reactor (MBBR) systems, are widely used to treat wastewater. Biofilm development is important for MBBR systems as much of the microbial biomass is retained within reactors as biofilm on suspended carriers. Little is known about this process of biofilm development and the microorganisms upon which MBBRs rely. We documented successional changes in microbial communities as biofilms established in two full-scale MBBR systems treating municipal wastewater over two seasons. 16S rRNA gene-targeted pyrosequencing and clone libraries were used to describe microbial communities. These data indicate a successional process that commences with the establishment of an aerobic community dominated by Gammaproteobacteria (up to 52 % of sequences). Over time, this community shifts towards dominance by putatively anaerobic organisms including Deltaproteobacteria and Clostridiales. Significant differences were observed between the two wastewater treatment plants (WWTPs), mostly due to a large number of sequences (up to 55 %) representing Epsilonproteobacteria (mostly Arcobacter) at one site. Archaea in young biofilms included several lineages of Euryarchaeota and Crenarchaeota. In contrast, the mature biofilm consisted entirely of Methanosarcinaceae (Euryarchaeota). This study provides new insights into the community structure of developing biofilms at full-scale WWTPs and provides the basis for optimizing MBBR start-up and operational parameters.
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Patterned biofilm formation reveals a mechanism for structural heterogeneity in bacterial biofilms.
Gu, Huan; Hou, Shuyu; Yongyat, Chanokpon; De Tore, Suzanne; Ren, Dacheng
2013-09-03
Bacterial biofilms are ubiquitous and are the major cause of chronic infections in humans and persistent biofouling in industry. Despite the significance of bacterial biofilms, the mechanism of biofilm formation and associated drug tolerance is still not fully understood. A major challenge in biofilm research is the intrinsic heterogeneity in the biofilm structure, which leads to temporal and spatial variation in cell density and gene expression. To understand and control such structural heterogeneity, surfaces with patterned functional alkanthiols were used in this study to obtain Escherichia coli cell clusters with systematically varied cluster size and distance between clusters. The results from quantitative imaging analysis revealed an interesting phenomenon in which multicellular connections can be formed between cell clusters depending on the size of interacting clusters and the distance between them. In addition, significant differences in patterned biofilm formation were observed between wild-type E. coli RP437 and some of its isogenic mutants, indicating that certain cellular and genetic factors are involved in interactions among cell clusters. In particular, autoinducer-2-mediated quorum sensing was found to be important. Collectively, these results provide missing information that links cell-to-cell signaling and interaction among cell clusters to the structural organization of bacterial biofilms.
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Environmental factors that shape biofilm formation.
Toyofuku, Masanori; Inaba, Tomohiro; Kiyokawa, Tatsunori; Obana, Nozomu; Yawata, Yutaka; Nomura, Nobuhiko
2016-01-01
Cells respond to the environment and alter gene expression. Recent studies have revealed the social aspects of bacterial life, such as biofilm formation. Biofilm formation is largely affected by the environment, and the mechanisms by which the gene expression of individual cells affects biofilm development have attracted interest. Environmental factors determine the cell's decision to form or leave a biofilm. In addition, the biofilm structure largely depends on the environment, implying that biofilms are shaped to adapt to local conditions. Second messengers such as cAMP and c-di-GMP are key factors that link environmental factors with gene regulation. Cell-to-cell communication is also an important factor in shaping the biofilm. In this short review, we will introduce the basics of biofilm formation and further discuss environmental factors that shape biofilm formation. Finally, the state-of-the-art tools that allow us investigate biofilms under various conditions are discussed.
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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 100μg/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 100μg/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 25μg/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. Copyright © 2014 Elsevier B.V. All rights reserved.
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Candida Infections of Medical Devices
Kojic, Erna M.; Darouiche, Rabih O.
2004-01-01
The number of indwelling medical devices is escalating, and an increasing proportion of device-related infections are being caused by Candida spp. Candida spp. produce biofilms on synthetic materials, which facilitates adhesion of the organisms to devices and renders them relatively refractory to medical therapy. Management of device-related Candida infections can be challenging. Removal of the infected device is generally needed to establish cure of Candida infections of medical devices. However, since the pathogenesis of Candida bloodstream infection is complicated, more studies are necessary to determine the role of catheter exchange in patients with both gastrointestinal tract mucositis and indwelling catheters. The medical and economic impact of these infections is enormous. PMID:15084500
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Three-dimensional biofilm structure quantification.
Beyenal, Haluk; Donovan, Conrad; Lewandowski, Zbigniew; Harkin, Gary
2004-12-01
Quantitative parameters describing biofilm physical structure have been extracted from three-dimensional confocal laser scanning microscopy images and used to compare biofilm structures, monitor biofilm development, and quantify environmental factors affecting biofilm structure. Researchers have previously used biovolume, volume to surface ratio, roughness coefficient, and mean and maximum thicknesses to compare biofilm structures. The selection of these parameters is dependent on the availability of software to perform calculations. We believe it is necessary to develop more comprehensive parameters to describe heterogeneous biofilm morphology in three dimensions. This research presents parameters describing three-dimensional biofilm heterogeneity, size, and morphology of biomass calculated from confocal laser scanning microscopy images. This study extends previous work which extracted quantitative parameters regarding morphological features from two-dimensional biofilm images to three-dimensional biofilm images. We describe two types of parameters: (1) textural parameters showing microscale heterogeneity of biofilms and (2) volumetric parameters describing size and morphology of biomass. The three-dimensional features presented are average (ADD) and maximum diffusion distances (MDD), fractal dimension, average run lengths (in X, Y and Z directions), aspect ratio, textural entropy, energy and homogeneity. We discuss the meaning of each parameter and present the calculations in detail. The developed algorithms, including automatic thresholding, are implemented in software as MATLAB programs which will be available at site prior to publication of the paper.
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Effect of ferrocene-substituted porphyrin RL-91 on Candida albicans biofilm formation.
Lippert, Rainer; Vojnovic, Sandra; Mitrovic, Aleksandra; Jux, Norbert; Ivanović-Burmazović, Ivana; Vasiljevic, Branka; Stankovic, Nada
2014-08-01
Ferrocene-substituted porphyrin RL-91 exhibits antifungal activity against opportune human pathogen Candida albicans. RL-91 efficiently inhibits growth of both planktonic C. albicans cells and cells within biofilms without photoactivation. The minimal inhibitory concentration for plankton form (PMIC) was established to be 100 μg/mL and the same concentration killed 80% of sessile cells in the mature biofilm (SMIC80). Furthermore PMIC of RL-91 efficiently prevents C. albicans biofilm formation. RL-91 is cytotoxic for human fibroblasts in vitro in concentration of 10 μg/mL, however it does not cause hemolysis in concentrations of up to 50 μg/mL. These findings open possibility for application of RL-91 as an antifungal agent for external antibiofilm treatment of medical devices as well as a scaffold for further development of porphyrin based systemic antifungals. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Quorum-Quenching Human Designer Cells for Closed-Loop Control of Pseudomonas aeruginosa Biofilms.
Sedlmayer, Ferdinand; Jaeger, Tina; Jenal, Urs; Fussenegger, Martin
2017-08-09
Current antibiotics gradually lose their efficacy against chronic Pseudomonas aeruginosa infections due to development of increased resistance mediated by biofilm formation, as well as the large arsenal of microbial virulence factors that are coordinated by the cell density-dependent phenomenon of quorum sensing. Here, we address this issue by using synthetic biology principles to rationally engineer quorum-quencher cells with closed-loop control to autonomously dampen virulence and interfere with biofilm integrity. Pathogen-derived signals dynamically activate a synthetic mammalian autoinducer sensor driving downstream expression of next-generation anti-infectives. Engineered cells were able to sensitively score autoinducer levels from P. aeruginosa clinical isolates and mount a 2-fold defense consisting of an autoinducer-inactivating enzyme to silence bacterial quorum sensing and a bipartite antibiofilm effector to dissolve the biofilm matrix. The self-guided cellular device fully cleared autoinducers, potentiated bacterial antibiotic susceptibility, substantially reduced biofilms, and alleviated cytotoxicity to lung epithelial cells. We believe this strategy of dividing otherwise coordinated pathogens and breaking up their shielded stronghold represents a blueprint for cellular anti-infectives in the postantibiotic era.
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Exploring the applications of invertebrate host-pathogen models for in vivo biofilm infections.
Edwards, Sarah; Kjellerup, Birthe V
2012-07-01
In the natural environment, microorganisms exist together in self-produced polymeric matrix biofilms. Often, several species, which can belong to both bacterial and fungal kingdoms, coexist and interact in ways which are not completely understood. Biofilm infections have become prevalent largely in medical settings because of the increasing use of indwelling medical devices such as catheters or prosthetics. These infections are resistant to common antimicrobial therapies because of the inherent nature of their structure. In terms of infectious biofilms, it is important to understand the microbe-microbe interactions and how the host immune system reacts in order to discover therapeutic targets. Currently, single infection immune response studies are thriving with the use of invertebrate models. This review highlights the advances in single microbial-host immune response as well as the promising aspects of polymicrobial biofilm study in five invertebrate models: Lemna minor (duckweed), Arabidopsis thaliana (thale cress), Dictyostelium discoideum (slime mold), Drosophila melanogaster (common fruit fly), and Caenorhabditis elegans (roundworm). © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
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Colloidal silver: a novel treatment for Staphylococcus aureus biofilms?
Goggin, Rachel; Jardeleza, Camille; Wormald, Peter-John; Vreugde, Sarah
2014-03-01
Colloidal silver is an alternative medicine consisting of silver particles suspended in water. After using this solution as a nasal spray, the symptoms of a previously recalcitrant Staphylococcus aureus (S. aureus)-infected chronic rhinosinusitis patient were observed to have improved markedly. The aim of this study was to determine whether colloidal silver has any direct bactericidal effects on these biofilms in vitro. S. aureus biofilms were grown from the ATCC 25923 reference strain on Minimum Biofilm Eradication Concentration (MBEC) device pegs, and treated with colloidal silver. Concentrations tested ranged from 10 to 150 μL colloidal silver diluted to 200 μL with sterile water in 50 μL cerebrospinal fluid (CSF) broth. Control pegs were exposed to equivalent volumes of CSF broth and sterile water. The sample size was 4 biomass values per treatment or control group. Confocal scanning laser microscopy and COMSTAT software were used to quantify biofilms 24 hours after treatment. Significant differences from control were found for all concentrations tested bar the lowest of 10 μL colloidal silver in 200 μL. At 20 μL colloidal silver, the reduction in biomass was 98.9% (mean difference between control and treatment = -4.0317 μm(3) /μm(2) , p < 0.0001). A maximum biomass reduction of 99.8% was reached at both 100 and 150 μL colloidal silver (mean differences = -4.0681 and -4.0675μm(3) /μm(2) , respectively, p < 0.0001). Colloidal silver directly attenuates in vitro S. aureus biofilms. © 2014 ARS-AAOA, LLC.
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Robinson, C; Kirkham, J; Percival, R; Shore, R C; Bonass, W A; Brookes, S J; Kusa, L; Nakagaki, H; Kato, K; Nattress, B
1997-01-01
The study of plaque biofilms in the oral cavity is difficult as plaque removal inevitably disrupts biofilm integrity precluding kinetic studies involving the penetration of components and metabolism of substrates in situ. A method is described here in which plaque is formed in vivo under normal (or experimental) conditions using a collection device which can be removed from the mouth after a specified time without physical disturbance to the plaque biofilm, permitting site-specific analysis or exposure of the undisturbed plaque to experimental conditions in vitro. Microbiological analysis revealed plaque flora which was similar to that reported from many natural sources. Analytical data can be related to plaque volume rather than weight. Using this device, plaque fluoride concentrations have been shown to vary with plaque depth and in vitro short-term exposure to radiolabelled components may be carried out, permitting important conclusions to be drawn regarding the site-specific composition and dynamics of dental plaque.
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Ahmadi, Mohammed S.; Lee, Hiu Ham; Sanchez, David A.; Friedman, Adam J.; Tar, Moses T.; Davies, Kelvin P.; Nosanchuk, Joshua D.
2016-01-01
Candida albicans is a leading nosocomial pathogen. Today, candidal biofilms are a significant cause of catheter infections, and such infections are becoming increasingly responsible for the failure of medical-implanted devices. C. albicans forms biofilms in which fungal cells are encased in an autoproduced extracellular polysaccharide matrix. Consequently, the enclosed fungi are protected from antimicrobial agents and host cells, providing a unique niche conducive to robust microbial growth and a harbor for recurring infections. Here we demonstrate that a recently developed platform comprised of nanoparticles that release therapeutic levels of nitric oxide (NO-np) inhibits candidal biofilm formation, destroys the extracellular polysaccharide matrices of mature fungal biofilms, and hinders biofilm development on surface biomaterials such as the lumen of catheters. We found NO-np to decrease both the metabolic activity of biofilms and the cell viability of C. albicans in vitro and in vivo. Furthermore, flow cytometric analysis found NO-np to induce apoptosis in biofilm yeast cells in vitro. Moreover, NO-np behave synergistically when used in combination with established antifungal drug therapies. Here we propose NO-np as a novel treatment modality, especially in combination with standard antifungals, for the prevention and/or remediation of fungal biofilms on central venous catheters and other medical devices. PMID:26810653
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Ahmadi, Mohammed S; Lee, Hiu Ham; Sanchez, David A; Friedman, Adam J; Tar, Moses T; Davies, Kelvin P; Nosanchuk, Joshua D; Martinez, Luis R
2016-04-01
Candida albicansis a leading nosocomial pathogen. Today, candidal biofilms are a significant cause of catheter infections, and such infections are becoming increasingly responsible for the failure of medical-implanted devices.C. albicansforms biofilms in which fungal cells are encased in an autoproduced extracellular polysaccharide matrix. Consequently, the enclosed fungi are protected from antimicrobial agents and host cells, providing a unique niche conducive to robust microbial growth and a harbor for recurring infections. Here we demonstrate that a recently developed platform comprised of nanoparticles that release therapeutic levels of nitric oxide (NO-np) inhibits candidal biofilm formation, destroys the extracellular polysaccharide matrices of mature fungal biofilms, and hinders biofilm development on surface biomaterials such as the lumen of catheters. We found NO-np to decrease both the metabolic activity of biofilms and the cell viability ofC. albicansin vitroandin vivo Furthermore, flow cytometric analysis found NO-np to induce apoptosis in biofilm yeast cellsin vitro Moreover, NO-np behave synergistically when used in combination with established antifungal drug therapies. Here we propose NO-np as a novel treatment modality, especially in combination with standard antifungals, for the prevention and/or remediation of fungal biofilms on central venous catheters and other medical devices. Copyright © 2016, American Society for Microbiology. All Rights Reserved.
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Experimental evolution in biofilm populations
Steenackers, Hans P.; Parijs, Ilse; Foster, Kevin R.; Vanderleyden, Jozef
2016-01-01
Biofilms are a major form of microbial life in which cells form dense surface associated communities that can persist for many generations. The long-life of biofilm communities means that they can be strongly shaped by evolutionary processes. Here, we review the experimental study of evolution in biofilm communities. We first provide an overview of the different experimental models used to study biofilm evolution and their associated advantages and disadvantages. We then illustrate the vast amount of diversification observed during biofilm evolution, and we discuss (i) potential ecological and evolutionary processes behind the observed diversification, (ii) recent insights into the genetics of adaptive diversification, (iii) the striking degree of parallelism between evolution experiments and real-life biofilms and (iv) potential consequences of diversification. In the second part, we discuss the insights provided by evolution experiments in how biofilm growth and structure can promote cooperative phenotypes. Overall, our analysis points to an important role of biofilm diversification and cooperation in bacterial survival and productivity. Deeper understanding of both processes is of key importance to design improved antimicrobial strategies and diagnostic techniques. PMID:26895713
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Experimental evolution in biofilm populations.
Steenackers, Hans P; Parijs, Ilse; Dubey, Akanksha; Foster, Kevin R; Vanderleyden, Jozef
2016-05-01
Biofilms are a major form of microbial life in which cells form dense surface associated communities that can persist for many generations. The long-life of biofilm communities means that they can be strongly shaped by evolutionary processes. Here, we review the experimental study of evolution in biofilm communities. We first provide an overview of the different experimental models used to study biofilm evolution and their associated advantages and disadvantages. We then illustrate the vast amount of diversification observed during biofilm evolution, and we discuss (i) potential ecological and evolutionary processes behind the observed diversification, (ii) recent insights into the genetics of adaptive diversification, (iii) the striking degree of parallelism between evolution experiments and real-life biofilms and (iv) potential consequences of diversification. In the second part, we discuss the insights provided by evolution experiments in how biofilm growth and structure can promote cooperative phenotypes. Overall, our analysis points to an important role of biofilm diversification and cooperation in bacterial survival and productivity. Deeper understanding of both processes is of key importance to design improved antimicrobial strategies and diagnostic techniques. © FEMS 2016.
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Szilágyi, N; Kovács, R; Kenyeres, I; Csikor, Zs
2013-01-01
Biofilm development in a fixed bed biofilm reactor system performing municipal wastewater treatment was monitored aiming at accumulating colonization and maximum biofilm mass data usable in engineering practice for process design purposes. Initially a 6 month experimental period was selected for investigations where the biofilm formation and the performance of the reactors were monitored. The results were analyzed by two methods: for simple, steady-state process design purposes the maximum biofilm mass on carriers versus influent load and a time constant of the biofilm growth were determined, whereas for design approaches using dynamic models a simple biofilm mass prediction model including attachment and detachment mechanisms was selected and fitted to the experimental data. According to a detailed statistical analysis, the collected data have not allowed us to determine both the time constant of biofilm growth and the maximum biofilm mass on carriers at the same time. The observed maximum biofilm mass could be determined with a reasonable error and ranged between 438 gTS/m(2) carrier surface and 843 gTS/m(2), depending on influent load, and hydrodynamic conditions. The parallel analysis of the attachment-detachment model showed that the experimental data set allowed us to determine the attachment rate coefficient which was in the range of 0.05-0.4 m d(-1) depending on influent load and hydrodynamic conditions.
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Williams, Dustin L.; Haymond, Bryan S.; Woodbury, Kassie L.; Beck, J. Peter; Moore, David E.; Epperson, R. Tyler; Bloebaum, Roy D.
2012-01-01
Currently, the majority of animal models that are used to study biofilm-related infections utilize planktonic bacterial cells as initial inocula to produce positive signals of infection in biomaterials studies. However, the use of planktonic cells has potentially led to inconsistent results in infection outcomes. In this study, well-established biofilms of methicillin-resistant Staphylococcus aureus (MRSA) were grown and used as initial inocula in an animal model of a Type IIIB open fracture. The goal of the work was to establish, for the first time, a repeatable model of biofilm implant-related osteomyelitis wherein biofilms were used as initial inocula to test combination biomaterials. Results showed that 100% of animals that were treated with biofilms developed osteomyelitis, whereas 0% of animals not treated with biofilm developed infection. The development of this experimental model may lead to an important shift in biofilm and biomaterials research by showing that when biofilms are used as initial inocula, they may provide additional insights into how biofilm-related infections in the clinic develop and how they can be treated with combination biomaterials to eradicate and/or prevent biofilm formation. PMID:22492534
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Williams, Dustin L; Haymond, Bryan S; Woodbury, Kassie L; Beck, J Peter; Moore, David E; Epperson, R Tyler; Bloebaum, Roy D
2012-07-01
Currently, the majority of animal models that are used to study biofilm-related infections use planktonic bacterial cells as initial inocula to produce positive signals of infection in biomaterials studies. However, the use of planktonic cells has potentially led to inconsistent results in infection outcomes. In this study, well-established biofilms of methicillin-resistant Staphylococcus aureus were grown and used as initial inocula in an animal model of a Type IIIB open fracture. The goal of the work was to establish, for the first time, a repeatable model of biofilm implant-related osteomyelitis, wherein biofilms were used as initial inocula to test combination biomaterials. Results showed that 100% of animals that were treated with biofilms developed osteomyelitis, whereas 0% of animals not treated with biofilm developed infection. The development of this experimental model may lead to an important shift in biofilm and biomaterials research by showing that when biofilms are used as initial inocula, they may provide additional insights into how biofilm-related infections in the clinic develop and how they can be treated with combination biomaterials to eradicate and/or prevent biofilm formation. Copyright © 2012 Wiley Periodicals, Inc.
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Shewanella putrefaciens Adhesion and Biofilm Formation on Food Processing Surfaces
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
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Haddad, Peter A; Mah, Thien-Fah; Mussivand, Tofy
2016-08-01
Biofilms are communities of bacteria that can cause infections which are resistant to the immune system and antimicrobial treatments, posing a significant threat for patients with implantable and indwelling medical devices. The purpose of our research was to determine if utilizing specific parameters for electric currents in conjunction with antibiotics could effectively treat a highly resistant biofilm. Our study evaluated the impact of 16 μg/mL of vancomycin with or without 22 or 333 μA of direct electric current (DC) generated by stainless steel electrodes against 24-, 48-, and 72-h-old Staphylococcus epidermidis biofilms formed on titanium coupons. An increase in effectiveness of vancomycin was observed with the combination of 333 μA of electric current against 48-h-old biofilms (P value = 0.01) as well as in combination with 22 μA of electric current against 72-h-old biofilms (P value = 0.04); 333 μA of electric current showed the most significant impact on the effectiveness of vancomycin against S. epidermidis biofilms demonstrating a bioelectric effect previously not observed against this strain of bacteria. © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.
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NASA Astrophysics Data System (ADS)
Xiu, Kemao
Bacterial infection and biofilm formation cause serious medical, industrial, and environmental problems. In biomedical applications, bacterial contamination of medical devices often leads to infectious diseases accompanied with pain, suffer, and even death. Polyurethane (PU) is widely in biomedical applications due to its good mechanical properties and biocompatibility. However, its vulnerability to bacterial biofilm formation seriously limits its wider uses. Prior studies have shown that N-halamines could be incorporated into PU to achieve antimicrobial and biofilm-controlling effects through grafting, blending, and/or coating. To broaden the selection of modification methods in the development antimicrobial PU, this study synthesized polyurethane/polymeric N-halamine semi-interpenetrating polymer networks (semi-IPN). Polymerizable monomeric N-halamines were swollen into PU with initiators and crosslink agents. Post polymerization of the monomers led to the formation of semi-IPN with linear PU and N-halamine polymer networks. The semi-IPNs showed excellent antimicrobial and biofilm controlling ability towards both gram-positive and gram-negative bacteria. The effects of hydrophilicity, surface grafted N-halamine and structural characteristics of N-halamine on the antimicrobial behavior of the resulting semi-IPNs were also investigated.
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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.
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[EFFECT OF PULSE-PERIODIC CORONA DISCHARGE ON VIABILITY OF ESCHERICHIA COLI M17 CELLS IN BIOFILMS].
Rybalchenko, O V; Stepanova, O M; Orlova, O G; Astafiev, A M; Kudryavtsev, A A; Kapustina, V V
2015-01-01
Detection of bactericidal effect of pulse-periodic corona discharge (PPCD) on cells and biofilms of Escherichia coli M17. A gas-discharge device was created based on PPCD in air with power supply parameters: amplitude values of voltage of 30 - 60 kV, pulse repetition rate of 250 - 400 kHz. Ultrastructure changes in cells and biofilms of E. coli M17, affected by PPCD, generated in air, were studied by typical methods of transmission electron microscopy. Disturbances of integrity of surface and abyssal structures of biofilms, as well as changes of morphological properties of E. coli M17 cells, characteristic for sub-lethal heat impact, were detected. Destructive changes of bacterial cells were developed by formation of focal disturbance of cytoplasmic membrane, extension of periplasmic space, formation of globular structures, characteristic for heat effect, and destruction of cytoplasm. Bactericidal effect of PPCD on E. coli M17 cells as part of biofilms was shown. Destructive morphological changes in cells and biofilms of E. coli M17 after the effect of PPCD were detected for the first time on electron-microscopic level.
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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.
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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
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Bucher, Tabitha; Kartvelishvily, Elena; Kolodkin-Gal, Ilana
2016-10-09
This work assesses different methodologies to study the impact of small molecule biofilm inhibitors, such as D-amino acids, on the development and resilience of Bacillus subtilis biofilms. First, methods are presented that select for small molecule inhibitors with biofilm-specific targets in order to separate the effect of the small molecule inhibitors on planktonic growth from their effect on biofilm formation. Next, we focus on how inoculation conditions affect the sensitivity of multicellular, floating B. subtilis cultures to small molecule inhibitors. The results suggest that discrepancies in the reported effects of such inhibitors such as D-amino acids are due to inconsistent pre-culture conditions. Furthermore, a recently developed protocol is described for evaluating the contribution of small molecule treatments towards biofilm resistance to antibacterial substances. Lastly, scanning electron microscopy (SEM) techniques are presented to analyze the three-dimensional spatial arrangement of cells and their surrounding extracellular matrix in a B. subtilis biofilm. SEM facilitates insight into the three-dimensional biofilm architecture and the matrix texture. A combination of the methods described here can greatly assist the study of biofilm development in the presence and absence of biofilm inhibitors, and shed light on the mechanism of action of these inhibitors.
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Candida/Candida biofilms. First description of dual-species Candida albicans/C. rugosa biofilm.
Martins, Carlos Henrique Gomes; Pires, Regina Helena; Cunha, Aline Oliveira; Pereira, Cristiane Aparecida Martins; Singulani, Junya de Lacorte; Abrão, Fariza; Moraes, Thais de; Mendes-Giannini, Maria José Soares
2016-04-01
Denture liners have physical properties that favour plaque accumulation and colonization by Candida species, irritating oral tissues and causing denture stomatitis. To isolate and determine the incidence of oral Candida species in dental prostheses, oral swabs were collected from the dental prostheses of 66 patients. All the strains were screened for their ability to form biofilms; both monospecies and dual-species combinations were tested. Candida albicans (63 %) was the most frequently isolated microorganism; Candida tropicalis (14 %), Candida glabrata (13 %), Candida rugosa (5 %), Candida parapsilosis (3 %), and Candida krusei (2 %) were also detected. The XTT assay showed that C. albicans SC5314 possessed a biofilm-forming ability significantly higher (p < 0.001) than non-albicans Candida strains, after 6 h 37 °C. The total C. albicans CFU from a dual-species biofilm was less than the total CFU of a monospecies C. albicans biofilm. In contrast to the profuse hyphae verified in monospecies C. albicans biofilms, micrographies showed that the C. albicans/non-albicans Candida biofilms consisted of sparse yeast forms and profuse budding yeast cells that generated a network. These results suggested that C. albicans and the tested Candida species could co-exist in biofilms displaying apparent antagonism. The study provide the first description of C. albicans/C. rugosa mixed biofilm. Copyright © 2016 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.
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Ivleva, Natalia P; Kubryk, Patrick; Niessner, Reinhard
2017-07-01
Biofilms represent the predominant form of microbial life on our planet. These aggregates of microorganisms, which are embedded in a matrix formed by extracellular polymeric substances, may colonize nearly all interfaces. Detailed knowledge of microorganisms enclosed in biofilms as well as of the chemical composition, structure, and functions of the complex biofilm matrix and their changes at different stages of the biofilm formation and under various physical and chemical conditions is relevant in different fields. Important research topics include the development and improvement of antibiotics and medical devices and the optimization of biocides, antifouling strategies, and biological wastewater treatment. Raman microspectroscopy is a capable and nondestructive tool that can provide detailed two-dimensional and three-dimensional chemical information about biofilm constituents with the spatial resolution of an optical microscope and without interference from water. However, the sensitivity of Raman microspectroscopy is rather limited, which hampers the applicability of Raman microspectroscopy especially at low biomass concentrations. Fortunately, the resonance Raman effect as well as surface-enhanced Raman scattering can help to overcome this drawback. Furthermore, the combination of Raman microspectroscopy with other microscopic techniques, mass spectrometry techniques, or particularly with stable-isotope techniques can provide comprehensive information on monospecies and multispecies biofilms. Here, an overview of different Raman microspectroscopic techniques, including resonance Raman microspectroscopy and surface-enhanced Raman scattering microspectroscopy, for in situ detection, visualization, identification, and chemical characterization of biofilms is given, and the main feasibilities and limitations of these techniques in biofilm research are presented. Future possibilities of and challenges for Raman microspectroscopy alone and in combination with other
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Proctor, Caitlin R; Reimann, Mauro; Vriens, Bas; Hammes, Frederik
2017-12-14
Shower hoses offer an excellent bacterial growth environment in close proximity to a critical end-user exposure route within building drinking water plumbing. However, the health risks associated with and processes underlying the development of biofilms in shower hoses are poorly studied. In a global survey, biofilms from 78 shower hoses from 11 countries were characterized in terms of cell concentration (4.1 × 10 4 -5.8 × 10 8 cells/cm 2 ), metal accumulation (including iron, lead, and copper), and microbiome composition (including presence of potential opportunistic pathogens). In countries using disinfectant, biofilms had on average lower cell concentrations and diversity. Metal accumulation (up to 5 μg-Fe/cm 2 , 75 ng-Pb/cm 2 , and 460 ng-Cu/cm 2 ) seemed to be partially responsible for discoloration in biofilms, and likely originated from other pipes upstream in the building. While some genera that may contain potential opportunistic pathogens (Legionella, detected in 21/78 shower hoses) were positively correlated with biofilm cell concentration, others (Mycobacterium, Pseudomonas) had surprisingly non-existent or negative correlations with biofilm cell concentrations. In a controlled study, 15 identical shower hoses were installed for the same time period in the same country, and both stagnant and flowing water samples were collected. Ecological theory of dispersal and selection helped to explain microbiome composition and diversity of different sample types. Shower hose age was related to metal accumulation but not biofilm cell concentration, while frequency of use appeared to influence biofilm cell concentration. This study shows that shower hose biofilms are clearly a critical element of building drinking water plumbing, and a potential target for building drinking water plumbing monitoring. Copyright © 2017 Elsevier Ltd. All rights reserved.
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In vitro management of hospital Pseudomonas aeruginosa biofilm using indigenous T7-like lytic phage.
Ahiwale, Sangeeta; Tamboli, Nilofer; Thorat, Kiran; Kulkarni, Rajendra; Ackermann, Hans; Kapadnis, Balasaheb
2011-02-01
Pseudomonas aeruginosa, a human pathogen capable of forming biofilm and contaminating medical settings, is responsible for 65% mortality in the hospitals all over the world. This study was undertaken to isolate lytic phages against biofilm forming Ps. aeruginosa hospital isolates and to use them for in vitro management of biofilms in the microtiter plate. Multidrug resistant strains of Ps. aeruginosa were isolated from the hospital environment in and around Pimpri-Chinchwad, Maharashtra by standard microbiological methods. Lytic phages against these strains were isolated from the Pavana river water by double agar layer plaque assay method. A wide host range phage bacterial virus Ps. aeruginosa phage (BVPaP-3) was selected. Electron microscopy revealed that BVPaP-3 phage is a T7-like phage and is a relative of phage species gh-1. A phage at MOI-0.001 could prevent biofilm formation by Ps. aeruginosa hospital strain-6(HS6) on the pegs within 24 h. It could also disperse pre-formed biofilms of all hospital isolates (HS1-HS6) on the pegs within 24 h. Dispersion of biofilm was studied by monitoring log percent reduction in cfu and log percent increase in pfu of respective bacterium and phage on the peg as well as in the well. Scanning electron microscopy confirmed that phage BVPaP-3 indeed causes biofilm reduction and bacterial cell killing. Laboratory studies prove that BVPaP-3 is a highly efficient phage in preventing and dispersing biofilms of Ps. aeruginosa. Phage BVPaP-3 can be used as biological disinfectant to control biofilm problem in medical devices.
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NASA Astrophysics Data System (ADS)
Deb, Ananya; Vimala, R.
The present study focuses on the development of an in vitro model system for biofilm growth by Pseudomonas aerouginosa onto small discs of foley catheter. Catheter disc used for the study was coated with graphene oxide-titanium oxide composite (GO-TiO2) and titanium oxide (TiO2) and characterized through XRD, UV-visible spectroscopy. Morphological analysis was done by scanning electron microscopy (SEM). The biofilm formed on the catheter surface was quantified by crystal violet (CV) staining method and a colorimetric assay (MTT assay) which involves the reduction of tetrazolium salt. The catheter coated with GO-TiO2 showed reduced biofilm growth in comparison to the TiO2-coated and uncoated catheter, thus indicating that it could be successfully used in coating biomedical devices to prevent biofilm formation which is a major cause of nosocomial infection.
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ERIC Educational Resources Information Center
Richardson, D. Theophilus; Deering, Michelle J.
2011-01-01
It is always an enlightening experience to observe how ideas around change are executed. The Calgary Board of Education program for inducting new teachers into its system merited some investigation. For a period of six weeks, the authors participated in this process, with a view that, some elements of the program could be used in a similar format…
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Removal of naturally grown human biofilm with an atmospheric pressure plasma jet: An in-vitro study.
Jablonowski, Lukasz; Fricke, Katja; Matthes, Rutger; Holtfreter, Birte; Schlüter, Rabea; von Woedtke, Thomas; Weltmann, Klaus-Dieter; Kocher, Thomas
2017-05-01
The removal of biofilm is a prerequisite for a successful treatment of biofilm-associated diseases. In this study, we compared the feasibility of an atmospheric pressure plasma device with a sonic powered brush to remove naturally grown supragingival biofilm from extracted teeth. Twenty-four periodontally hopeless teeth were extracted. Argon jet plasma with an oxygen admixture of 1 vol% and a sonically driven brush were used to remove biofilm with application times of 60 s, 180 s and 300 s. The treatment efficiency was assessed with light microscopy, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The highest biofilm removal rate was observed after an application time of 180 s/300 s with the sonic brush (80.4%/86.2%), plasma (75.5%/89.0%). These observations were confirmed by SEM. According to XPS analysis, plasma treatment decreased the amount of carbon and nitrogen, indicative of an extensive removal of proteins. Plasma treatment of naturally grown biofilm resulted in an effective cleaning of the tooth surface and was comparable to mechanical treatment. Treatment time had a significant influence on plaque reduction. These results showed that plasma could be a useful adjuvant treatment modality in cases where biofilm removal or reduction plays a decisive role, such as periodontitis and peri-implantitis. Plasma-treated biofilm on an extracted tooth. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Schiebel, Juliane; Böhm, Alexander; Nitschke, Jörg; Burdukiewicz, Michał; Weinreich, Jörg; Ali, Aamir; Roggenbuck, Dirk; Rödiger, Stefan
2017-01-01
chronic and device-related infections due to their high resistance to antibiotics and the host immune system. In nonpathogenic Escherichia coli, cell surface components playing a pivotal role in biofilm formation are well known. In contrast, there is poor information for their role in biofilm formation of pathogenic isolates. Our study provides insights into the correlation of biofilm-associated genes or specific phenotypes with the biofilm formation ability of commensal and pathogenic E. coli. Additionally, we describe a newly developed method enabling qualitative biofilm analysis by automated image analysis, which is beneficial for high-throughput screenings. Our results help to establish a better understanding of E. coli biofilm formation. PMID:28986371
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Schiebel, Juliane; Böhm, Alexander; Nitschke, Jörg; Burdukiewicz, Michał; Weinreich, Jörg; Ali, Aamir; Roggenbuck, Dirk; Rödiger, Stefan; Schierack, Peter
2017-12-15
Bacterial biofilm formation is a widespread phenomenon and a complex process requiring a set of genes facilitating the initial adhesion, maturation, and production of the extracellular polymeric matrix and subsequent dispersal of bacteria. Most studies on Escherichia coli biofilm formation have investigated nonpathogenic E. coli K-12 strains. Due to the extensive focus on laboratory strains in most studies, there is poor information regarding biofilm formation by pathogenic E. coli isolates. In this study, we genotypically and phenotypically characterized 187 human clinical E. coli isolates representing various pathotypes (e.g., uropathogenic, enteropathogenic, and enteroaggregative E. coli ). We investigated the presence of biofilm-associated genes ("genotype") and phenotypically analyzed the isolates for motility and curli and cellulose production ("phenotype"). We developed a new screening method to examine the in vitro biofilm formation ability. In summary, we found a high prevalence of biofilm-associated genes. However, we could not detect a biofilm-associated gene or specific phenotype correlating with the biofilm formation ability. In contrast, we did identify an association of increased biofilm formation with a specific E. coli pathotype. Enteroaggregative E. coli (EAEC) was found to exhibit the highest capacity for biofilm formation. Using our image-based technology for the screening of biofilm formation, we demonstrated the characteristic biofilm formation pattern of EAEC, consisting of thick bacterial aggregates. In summary, our results highlight the fact that biofilm-promoting factors shown to be critical for biofilm formation in nonpathogenic strains do not reflect their impact in clinical isolates and that the ability of biofilm formation is a defined characteristic of EAEC. IMPORTANCE Bacterial biofilms are ubiquitous and consist of sessile bacterial cells surrounded by a self-produced extracellular polymeric matrix. They cause chronic and device
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Banche, Giuliana; Bistolfi, Alessandro; Allizond, Valeria; Galletta, Claudia; Iannantuoni, Maria Rita; Marra, Elisa Simona; Merlino, Chiara; Massè, Alessandro; Cuffini, Anna Maria
2018-06-18
Prosthetic joint infection diagnosis is often difficult since biofilm-embedded microorganisms attach well to the prosthetic surfaces and resist their detection by conventional methods. DL-dithiothreitol has been described as a valid method for biofilm detachment on orthopedic devices. We report the case of an occasional detection of Listeria monocytogenes in a non immuno-compromised patient with a preoperative diagnosis of aseptic loosening. The infection diagnosis due to such rare bacteria was made postoperatively, thanks to a DL-dithiothreitol-based device. This may be considered a feasible approach for the microbiological analysis of prosthetic joint infection, considering that a prompt diagnosis of such biofilm-associated infections could bring some advantages, such as an early and appropriate antibiotic therapy administration and a reduction of undiagnosed infections.
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Yoon, Hye Young; Lee, Si Young
2017-11-01
In this study, a laboratory model to reproduce dental unit waterline (DUWL) biofilms was developed using a CDC biofilm reactor (CBR). Bacteria obtained from DUWLs were filtered and cultured in Reasoner's 2A (R2A) for 10 days, and were subsequently stored at -70°C. This stock was cultivated on R2A in batch mode. After culturing for five days, the bacteria were inoculated into the CBR. Biofilms were grown on polyurethane tubing for four days. Biofilm accumulation and thickness was 1.3 × 10 5 CFU cm -2 and 10-14 μm respectively, after four days. Bacteria in the biofilms included cocci and rods of short and medium lengths. In addition, 38 bacterial genera were detected in biofilms. In this study, the suitability and reproducibility of the CBR model for DUWL biofilm formation were demonstrated. The model provides a foundation for the development of bacterial control methods for DUWLs.
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New Technologies for Studying Biofilms
FRANKLIN, MICHAEL J.; CHANG, CONNIE; AKIYAMA, TATSUYA; BOTHNER, BRIAN
2016-01-01
Bacteria have traditionally been studied as single-cell organisms. In laboratory settings, aerobic bacteria are usually cultured in aerated flasks, where the cells are considered essentially homogenous. However, in many natural environments, bacteria and other microorganisms grow in mixed communities, often associated with surfaces. Biofilms are comprised of surface-associated microorganisms, their extracellular matrix material, and environmental chemicals that have adsorbed to the bacteria or their matrix material. While this definition of a biofilm is fairly simple, biofilms are complex and dynamic. Our understanding of the activities of individual biofilm cells and whole biofilm systems has developed rapidly, due in part to advances in molecular, analytical, and imaging tools and the miniaturization of tools designed to characterize biofilms at the enzyme level, cellular level, and systems level. PMID:26350329
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Ashar, B S; Dang, J M; Krause, D; Luke, M C
2011-12-01
The FDA's Center for Devices and Radiological Health (CDRH) is responsible for providing reasonable assurance of safety and effectiveness of all medical devices marketed within the US. To date, CDRH has cleared numerous hernia mesh devices for general use, but has not cleared/approved any mesh devices intended for certain specific uses, such as for infected wounds, hernia prevention, biofilm reduction, or prevention of adhesions. CDRH is requesting that manufacturers seeking specific hernia mesh device labeling claims consult with the Agency to determine the level of evidence necessary for justifying such claims.
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Harrison, Joe J; Turner, Raymond J; Ceri, Howard
2005-07-01
In this study, we examined Pseudomonas aeruginosa ATCC 27853 biofilm and planktonic cell susceptibility to metal cations. The minimum inhibitory concentration (MIC), the minimum bactericidal concentration (MBC) required to eradicate 100% of the planktonic population (MBC 100), and the minimum biofilm eradication concentration (MBEC) were determined using the MBEC trade mark-high throughput assay. Six metals - Co(2+), Ni(2+), Cu(2+), Zn(2+), Al(3+) and Pb(2+)- were each tested at 2, 4, 6, 8, 10 and 27 h of exposure to biofilm and planktonic cultures grown in rich or minimal media. With 2 or 4 h of exposure, biofilms were approximately 2-25 times more tolerant to killing by metal cations than the corresponding planktonic cultures. However, by 27 h of exposure, biofilm and planktonic bacteria were eradicated at approximately the same concentration in every instance. Viable cell counts evaluated at 2 and 27 h of exposure revealed that at high concentrations, most of the metals assayed had killed greater than 99.9% of biofilm and planktonic cell populations. The surviving cells were propogated in vitro and gave rise to biofilm and planktonic cultures with normal sensitivity to metals. Further, retention of copper by the biofilm matrix was investigated using the chelator sodium diethlydithiocarbamate. Formation of visible brown metal-chelates in biofilms treated with Cu(2+) suggests that the biofilm matrix may coordinate and sequester metal cations from the aqueous surroundings. Overall, our data suggest that both metal sequestration in the biofilm matrix and the presence of a small population of 'persister' cells may be contributing factors in the time-dependent tolerance of both planktonic cells and biofilms to high concentrations of metal cations.
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Saising, Jongkon; Singdam, Sudarat; Ongsakul, Metta; Voravuthikunchai, Supayang Piyawan
2012-08-01
Staphylococci involve infections in association with a number of bacterial virulence factors. Extracellular enzymes play an important role in staphylococcal pathogenesis. In addition, biofilm is known to be associated with their virulence. In this study, 149 staphylococcal isolates from acne lesions were investigated for their virulence factors including lipase, protease, and biofilm formation. Coagulase-negative staphylococci were demonstrated to present lipase and protease activities more often than coagulase-positive staphylococci. A microtiter plate method (quantitative method) and a Congo red agar method (qualitative method) were comparatively employed to assess biofilm formation. In addition, biofilm forming ability was commonly detected in a coagulase-negative group (97.7%, microtiter plate method and 84.7%, Congo red agar method) more frequently than in coagulase-positive organisms (68.8%, microtiter plate method and 62.5%, Congo red agar method). This study clearly confirms an important role for biofilm in coagulasenegative staphylococci which is of serious concern as a considerable infectious agent in patients with acnes and implanted medical devices. The Congo red agar method proved to be an easy method to quickly detect biofilm producers. Sensitivity of the Congo red agar method was 85.54% and 68.18% and accuracy was 84.7% and 62.5% in coagulase-negative and coagulase-positive staphylococci, respectively, while specificity was 50% in both groups. The results clearly demonstrated that a higher percentage of coagulasenegative staphylococci isolated from acne lesions exhibited lipase and protease activities, as well as biofilm formation, than coagulase-positive staphylococci.
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Staphopains Modulate Staphylococcus aureus Biofilm Integrity
Mootz, Joe M.; Malone, Cheryl L.; Shaw, Lindsey N.
2013-01-01
Staphylococcus aureus is a known cause of chronic biofilm infections that can reside on medical implants or host tissue. Recent studies have demonstrated an important role for proteinaceous material in the biofilm structure. The S. aureus genome encodes many secreted proteases, and there is growing evidence that these enzymes have self-cleavage properties that alter biofilm integrity. However, the specific contribution of each protease and mechanism of biofilm modulation is not clear. To address this issue, we utilized a sigma factor B (ΔsigB) mutant where protease activity results in a biofilm-negative phenotype, thereby creating a condition where the protease(s) responsible for the phenotype could be identified. Using a plasma-coated microtiter assay, biofilm formation was restored to the ΔsigB mutant through the addition of the cysteine protease inhibitor E-64 or by using Staphostatin inhibitors that specifically target the extracellular cysteine proteases SspB and ScpA (called Staphopains). Through construction of gene deletion mutants, we determined that an sspB scpA double mutant restored ΔsigB biofilm formation, and this recovery could be replicated in plasma-coated flow cell biofilms. Staphopain levels were also found to be decreased under biofilm-forming conditions, possibly allowing biofilm establishment. The treatment of S. aureus biofilms with purified SspB or ScpA enzyme inhibited their formation, and ScpA was also able to disperse an established biofilm. The antibiofilm properties of ScpA were conserved across S. aureus strain lineages. These findings suggest an underappreciated role of the SspB and ScpA cysteine proteases in modulating S. aureus biofilm architecture. PMID:23798534
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Schiavone, Brigida Immacolata Pia; Rosato, Antonio; Marilena, Muraglia; Gibbons, Simon; Bombardelli, Ezio; Verotta, Luisella; Franchini, Carlo; Corbo, Filomena
2013-09-27
Bacterial biofilms are organized communities of microorganisms, embedded in a self-produced matrix, growing on a biotic surface and resistant to many antimicrobial agents when associated with a medical device. These biofilms require the development of new strategies for the prevention and treatment of infectious disease, including the potential use of natural products. One interesting natural product example is Hypericum, a plant genus that contains species known to have antimicrobial properties. The major constituent of Hypericum perforatum is an unstable compound named hyperforin (1); for this reason it was not believed to play a significant role in the pharmacological effects. In this investigation a hydrogenated hyperforin analogue (2) was tested on several ATCC and clinical isolate strains, in their planktonic and biofilm form (Staphylococcus aureus, MRSA, and Enterococcus faecalis). Compound 2 was effective against planktonic and biofilm cultures, probably due to higher stability, showing the percentage of cells killed in the range from 45% to 52%. These results are noteworthy from the point of view of future development of these polyprenylated phloroglucinols as potential antibiotics.
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Maggot excretions inhibit biofilm formation on biomaterials.
Cazander, Gwendolyn; van de Veerdonk, Mariëlle C; Vandenbroucke-Grauls, Christina M J E; Schreurs, Marco W J; Jukema, Gerrolt N
2010-10-01
Biofilm-associated infections in trauma surgery are difficult to treat with conventional therapies. Therefore, it is important to develop new treatment modalities. Maggots in captured bags, which are permeable for larval excretions/secretions, aid in healing severe, infected wounds, suspect for biofilm formation. Therefore we presumed maggot excretions/secretions would reduce biofilm formation. We studied biofilm formation of Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella oxytoca, Enterococcus faecalis, and Enterobacter cloacae on polyethylene, titanium, and stainless steel. We compared the quantities of biofilm formation between the bacterial species on the various biomaterials and the quantity of biofilm formation after various incubation times. Maggot excretions/secretions were added to existing biofilms to examine their effect. Comb-like models of the biomaterials, made to fit in a 96-well microtiter plate, were incubated with bacterial suspension. The formed biofilms were stained in crystal violet, which was eluted in ethanol. The optical density (at 595 nm) of the eluate was determined to quantify biofilm formation. Maggot excretions/secretions were pipetted in different concentrations to (nonstained) 7-day-old biofilms, incubated 24 hours, and finally measured. The strongest biofilms were formed by S. aureus and S. epidermidis on polyethylene and the weakest on titanium. The highest quantity of biofilm formation was reached within 7 days for both bacteria. The presence of excretions/secretions reduced biofilm formation on all biomaterials. A maximum of 92% of biofilm reduction was measured. Our observations suggest maggot excretions/secretions decrease biofilm formation and could provide a new treatment for biofilm formation on infected biomaterials.
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Novel Method for Quantitative Estimation of Biofilms.
Syal, Kirtimaan
2017-10-01
Biofilm protects bacteria from stress and hostile environment. Crystal violet (CV) assay is the most popular method for biofilm determination adopted by different laboratories so far. However, biofilm layer formed at the liquid-air interphase known as pellicle is extremely sensitive to its washing and staining steps. Early phase biofilms are also prone to damage by the latter steps. In bacteria like mycobacteria, biofilm formation occurs largely at the liquid-air interphase which is susceptible to loss. In the proposed protocol, loss of such biofilm layer was prevented. In place of inverting and discarding the media which can lead to the loss of the aerobic biofilm layer in CV assay, media was removed from the formed biofilm with the help of a syringe and biofilm layer was allowed to dry. The staining and washing steps were avoided, and an organic solvent-tetrahydrofuran (THF) was deployed to dissolve the biofilm, and the absorbance was recorded at 595 nm. The protocol was tested for biofilm estimation of E. coli, B. subtilis and M. smegmatis, and compared with the traditional CV assays. Isoniazid drug molecule, a known inhibitor of M. smegmatis biofilm, was tested and its inhibitory effects were quantified by the proposed protocol. For ease in referring, this method has been described as the Syal method for biofilm quantification. This new method was found to be useful for the estimation of early phase biofilm and aerobic biofilm layer formed at the liquid-air interphase. The biofilms formed by all three tested bacteria-B. subtilis, E. coli and M. smegmatis, were precisely quantified.
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Inhibition of Staphylococcus epidermidis biofilms using polymerizable vancomycin derivatives.
Lawson, McKinley C; Hoth, Kevin C; Deforest, Cole A; Bowman, Christopher N; Anseth, Kristi S
2010-08-01
Biofilm formation on indwelling medical devices is a ubiquitous problem causing considerable patient morbidity and mortality. In orthopaedic surgery, this problem is exacerbated by the large number and variety of material types that are implanted. Metallic hardware in conjunction with polymethylmethacrylate (PMMA) bone cement is commonly used. We asked whether polymerizable derivatives of vancomycin might be useful to (1) surface modify Ti-6Al-4V alloy and to surface/bulk modify PMMA bone cement to prevent Staphylococcus epidermidis biofilm formation and (2) whether the process altered the compressive modulus, yield strength, resilience, and/or fracture strength of cement copolymers. A Ti-6Al-4V alloy was silanized with methacryloxypropyltrimethoxysilane in preparation for subsequent polymer attachment. Surfaces were then coated with polymers formed from PEG(375)-acrylate or a vancomycin-PEG(3400)-PEG(375)-acrylate copolymer. PMMA was loaded with various species, including vancomycin and several polymerizable vancomycin derivatives. To assess antibiofilm properties of these materials, initial bacterial adherence to coated Ti-6Al-4V was determined by scanning electron microscopy (SEM). Biofilm dry mass was determined on PMMA coupons; the compressive mechanical properties were also determined. SEM showed the vancomycin-PEG(3400)-acrylate-type surface reduced adherent bacteria numbers by approximately fourfold when compared with PEG(375)-acrylate alone. Vancomycin-loading reduced all mechanical properties tested; in contrast, loading a vancomycin-acrylamide derivative restored these deficits but demonstrated no antibiofilm properties. A polymerizable, PEGylated vancomycin derivative reduced biofilm attachment but resulted in inferior cement mechanical properties. The approaches presented here may offer new strategies for developing biofilm-resistant orthopaedic materials. Specifically, polymerizable derivatives of traditional antibiotics may allow for direct
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Kapoor, Vidushi; Rai, Rajanikant; Thiyagarajan, Durairaj; Mukherjee, Sandipan; Das, Gopal; Ramesh, Aiyagari
2017-08-04
Zinc-complexing ligands are prospective anti-biofilm agents because of the pivotal role of zinc in the formation of Staphylococcus aureus biofilm. Accordingly, the potential of a thiosemicarbazone (compound C1) and a benzothiazole-based ligand (compound C4) in the prevention of S. aureus biofilm formation was assessed. Compound C1 displayed a bimodal activity, hindering biofilm formation only at low concentrations and promoting biofilm growth at higher concentrations. In the case of C4, a dose-dependent inhibition of S. aureus biofilm growth was observed. Atomic force microscopy analysis suggested that at higher concentrations C1 formed globular aggregates, which perhaps formed a substratum that favored adhesion of cells and biofilm formation. In the case of C4, zinc supplementation experiments validated zinc complexation as a plausible mechanism of inhibition of S. aureus biofilm. Interestingly, C4 was nontoxic to cultured HeLa cells and thus has promise as a therapeutic anti-biofilm agent. The essential understanding of the structure-driven implications of zinc-complexing ligands acquired in this study might assist future screening regimes for identification of potent anti-biofilm agents. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
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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
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Conductive properties of methanogenic biofilms.
Li, Cheng; Lesnik, Keaton Larson; Liu, Hong
2018-02-01
Extracellular electron transfer between syntrophic partners needs to be efficiently maintained in methanogenic environments. Direct extracellular electron transfer via electrical current is an alternative to indirect hydrogen transfer but requires construction of conductive extracellular structures. Conductive mechanisms and relationship between conductivity and the community composition in mixed-species methanogenic biofilms are not well understood. The present study investigated conductive behaviors of methanogenic biofilms and examined the correlation between biofilm conductivity and community composition between different anaerobic biofilms enriched from the same inoculum. Highest conductivity observed in methanogenic biofilms was 71.8±4.0μS/cm. Peak-manner response of conductivity upon changes over a range of electrochemical potentials suggests that electron transfer in methanogenic biofilms occurs through redox driven super-exchange. The strong correlation observed between biofilm conductivity and Geobacter spp. in the metabolically diverse anaerobic communities suggests that the efficiency of DEET may provide pressure for microbial communities to select for species that can produce electrical conduits. Copyright © 2017 Elsevier B.V. All rights reserved.
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Electrochemical biofilm control: a review.
Sultana, Sujala T; Babauta, Jerome T; Beyenal, Haluk
2015-01-01
One of the methods of controlling biofilms that has widely been discussed in the literature is to apply a potential or electrical current to a metal surface on which the biofilm is growing. Although electrochemical biofilm control has been studied for decades, the literature is often conflicting, as is detailed in this review. The goals of this review are: (1) to present the current status of knowledge regarding electrochemical biofilm control; (2) to establish a basis for a fundamental definition of electrochemical biofilm control and requirements for studying it; (3) to discuss current proposed mechanisms; and (4) to introduce future directions in the field. It is expected that the review will provide researchers with guidelines on comparing datasets across the literature and generating comparable datasets. The authors believe that, with the correct design, electrochemical biofilm control has great potential for industrial use.
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Curran-Sills, Gwynn
2018-01-12
Presently, there is no literature that examines the reasons for the cancellation of amateur or professional mixed martial arts (MMA) bouts. The purpose of this study was to review the circumstances that lead to the cancellation of MMA bouts by Calgary ringside physicians during the pre-bout examination period and to identify any emerging patterns that may guide the regulatoin of this sport. The case-series was constructed from the Calgary Combative Sports Commission pre-bout examination records and the medical records submitted by each athlete from January 2010 to December 2016. Cancelled bouts in the pre-bout examination periods represented 5.4% of all MMA bouts in Calgary. A total of 25 reasons lead to bout cancellation and included the following: failure to obtain required neuroimaging (28.0%), neuroimaging abnormalities (24.0%), incomplete routine screening investigations (16.0%), exceeding maximum weight differential between the two athletes (16.0%), injury in the pre-competition period (8.0%), dehydration (4.0%), and ECG abnormalities (4.0%). The abnormalities on neuroimaging (n of 6) included the following: post traumatic gliosis on MRI (n = 1, 16.7%), flares diffusely and findings consistent with microhemorrhage on MRI (n = 1, 16.7%), chronic orbital fracture with fat pad extrusion on CT (n = 2, 33.3%), lacunar infarct on MRI (1), and unspecified MRI abnormality (n = 1, 16.7%). Twenty-two athletes had bouts cancelled and of these three athletes had their bouts stopped for two reasons. The following recommendations are presented and include: the creation of guidelines regarding pre- and post-bout neuroimaging, the implementation of industry-wide minimum medical screening standards, the adoption of a longitudinal approach to weight monitoring, the development of competent ringside physician groups, and active oversight by the Combative Sports Commission during the matchmaking process.
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Roy, Ranita; Tiwari, Monalisa; Donelli, Gianfranco; Tiwari, Vishvanath
2018-01-01
ABSTRACT Biofilm refers to the complex, sessile communities of microbes found either attached to a surface or buried firmly in an extracellular matrix as aggregates. The biofilm matrix surrounding bacteria makes them tolerant to harsh conditions and resistant to antibacterial treatments. Moreover, the biofilms are responsible for causing a broad range of chronic diseases and due to the emergence of antibiotic resistance in bacteria it has really become difficult to treat them with efficacy. Furthermore, the antibiotics available till date are ineffective for treating these biofilm related infections due to their higher values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), which may result in in-vivo toxicity. Hence, it is critically important to design or screen anti-biofilm molecules that can effectively minimize and eradicate biofilm related infections. In the present article, we have highlighted the mechanism of biofilm formation with reference to different models and various methods used for biofilm detection. A major focus has been put on various anti-biofilm molecules discovered or tested till date which may include herbal active compounds, chelating agents, peptide antibiotics, lantibiotics and synthetic chemical compounds along with their structures, mechanism of action and their respective MICs, MBCs, minimum biofilm inhibitory concentrations (MBICs) as well as the half maximal inhibitory concentration (IC50) values available in the literature so far. Different mode of action of anti biofilm molecules addressed here are inhibition via interference in the quorum sensing pathways, adhesion mechanism, disruption of extracellular DNA, protein, lipopolysaccharides, exopolysaccharides and secondary messengers involved in various signaling pathways. From this study, we conclude that the molecules considered here might be used to treat biofilm-associated infections after significant structural modifications, thereby
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Biofilm in drinking water systems is undesirable and effective biofilm control maintains public health. Free chlorine and monochloramine are commonly used as secondary drinking water disinfectants, but monochloramine is perceived to penetrate biofilm better than free chlorine. ...
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Almstrand, Robert; Persson, Frank; Daims, Holger; Ekenberg, Maria; Christensson, Magnus; Wilén, Britt-Marie; Sörensson, Fred; Hermansson, Malte
2014-01-01
Moving bed biofilm reactors (MBBRs) are increasingly used for nitrogen removal with nitritation-anaerobic ammonium oxidation (anammox) processes in wastewater treatment. Carriers provide protected surfaces where ammonia oxidizing bacteria (AOB) and anammox bacteria form complex biofilms. However, the knowledge about the organization of microbial communities in MBBR biofilms is sparse. We used new cryosectioning and imaging methods for fluorescence in situ hybridization (FISH) to study the structure of biofilms retrieved from carriers in a nitritation-anammox MBBR. The dimensions of the carrier compartments and the biofilm cryosections after FISH showed good correlation, indicating little disturbance of biofilm samples by the treatment. FISH showed that Nitrosomonas europaea/eutropha-related cells dominated the AOB and Candidatus Brocadia fulgida-related cells dominated the anammox guild. New carriers were initially colonized by AOB, followed by anammox bacteria proliferating in the deeper biofilm layers, probably in anaerobic microhabitats created by AOB activity. Mature biofilms showed a pronounced three-dimensional stratification where AOB dominated closer to the biofilm-water interface, whereas anammox were dominant deeper into the carrier space and towards the walls. Our results suggest that current mathematical models may be oversimplifying these three-dimensional systems and unless the multidimensionality of these systems is considered, models may result in suboptimal design of MBBR carriers. PMID:24481066
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Scopel, Marina; Abraham, Wolf-Rainer; Henriques, Amélia T; Macedo, Alexandre J
2013-02-01
Infections associated to microbial biofilms are involved in 80% of human infections and became a challenge concerning public health. Infections related to Staphylococcus epidermidis biofilms are presently commonly associated to medical devices, increasing treatment costs for this type of infection. Alternatives to eliminate this kind of disease have been employed in screening programs using diverse marine-derived fungi source of bioactive compounds capable to combat biofilm formation. In this work was isolated the dipeptide cis-cyclo(Leucyl-Tyrosyl) from a sponge associated Penicillium sp. possessing a remarkable inhibition up to 85% of biofilm formation without interfering with bacterial growth, confirmed by scanning electron microscopy. This is the first demonstration that cis-cyclo(Leucyl-Tyrosyl) is able to specifically inhibit biofilm formation adding another aspect to the broad spectrum of bioactivities of cyclic dipeptides. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Francolini, I.; Norris, P.; Piozzi, A.; Donelli, G.; Stoodley, P.
2004-01-01
In modern medicine, artificial devices are used for repair or replacement of damaged parts of the body, delivery of drugs, and monitoring the status of critically ill patients. However, artificial surfaces are often susceptible to colonization by bacteria and fungi. Once microorganisms have adhered to the surface, they can form biofilms, resulting in highly resistant local or systemic infections. At this time, the evidence suggests that (+)-usnic acid, a secondary lichen metabolite, possesses antimicrobial activity against a number of planktonic gram-positive bacteria, including Staphylococcus aureus, Enterococcus faecalis, and Enterococcus faecium. Since lichens are surface-attached communities that produce antibiotics, including usnic acid, to protect themselves from colonization by other bacteria, we hypothesized that the mode of action of usnic acid may be utilized in the control of medical biofilms. We loaded (+)-usnic acid into modified polyurethane and quantitatively assessed the capacity of (+)-usnic acid to control biofilm formation by either S. aureus or Pseudomonas aeruginosa under laminar flow conditions by using image analysis. (+)-Usnic acid-loaded polymers did not inhibit the initial attachment of S. aureus cells, but killing the attached cells resulted in the inhibition of biofilm. Interestingly, although P. aeruginosa biofilms did form on the surface of (+)-usnic acid-loaded polymer, the morphology of the biofilm was altered, possibly indicating that (+)-usnic acid interfered with signaling pathways. PMID:15504865
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Kilic, Tugba; Karaca, Basar; Ozel, Beste Piril; Ozcan, Birgul; Cokmus, Cumhur; Coleri Cihan, Arzu
2017-04-01
The ability of Aeribacillus pallidus E334 to produce pellicle and form a biofilm was studied. Optimal biofilm formation occurred at 60 °C, pH 7.5 and 1.5% NaCl. Extra polymeric substances (EPS) were composed of proteins and eDNA (21.4 kb). E334 formed biofilm on many surfaces, but mostly preferred polypropylene and glass. Using CLSM analysis, the network-like structure of the EPS was observed. The A. pallidus biofilm had a novel eDNA content. DNaseI susceptibility (86.8% removal) of eDNA revealed its importance in mature biofilms, but the purified eDNA was resistant to DNaseI, probably due to its extended folding outside the matrix. Among 15 cleaning agents, biofilms could be removed with alkaline protease and sodium dodecyl sulphate (SDS). The removal of cells from polypropylene and biomass on glass was achieved with combined SDS/alkaline protease treatment. Strong A. pallidus biofilms could cause risks for industrial processes and abiotic surfaces must be taken into consideration in terms of sanitation procedures.
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How Staphylococcus aureus biofilms develop their characteristic structure
Periasamy, Saravanan; Joo, Hwang-Soo; Duong, Anthony C.; Bach, Thanh-Huy L.; Tan, Vee Y.; Chatterjee, Som S.; Cheung, Gordon Y. C.; Otto, Michael
2012-01-01
Biofilms cause significant problems in the environment and during the treatment of infections. However, the molecular mechanisms underlying biofilm formation are poorly understood. There is a particular lack of knowledge about biofilm maturation processes, such as biofilm structuring and detachment, which are deemed crucial for the maintenance of biofilm viability and the dissemination of cells from a biofilm. Here, we identify the phenol-soluble modulin (PSM) surfactant peptides as key biofilm structuring factors in the premier biofilm-forming pathogen Staphylococcus aureus. We provide evidence that all known PSM classes participate in structuring and detachment processes. Specifically, absence of PSMs in isogenic S. aureus psm deletion mutants led to strongly impaired formation of biofilm channels, abolishment of the characteristic waves of biofilm detachment and regrowth, and loss of control of biofilm expansion. In contrast, induced expression of psm loci in preformed biofilms promoted those processes. Furthermore, PSMs facilitated dissemination from an infected catheter in a mouse model of biofilm-associated infection. Moreover, formation of the biofilm structure was linked to strongly variable, quorum sensing-controlled PSM expression in biofilm microenvironments, whereas overall PSM production remained constant to ascertain biofilm homeostasis. Our study describes a mechanism of biofilm structuring in molecular detail, and the general principle (i.e., quorum-sensing controlled expression of surfactants) seems to be conserved in several bacteria, despite the divergence of the respective biofilm-structuring surfactants. These findings provide a deeper understanding of biofilm development processes, which represents an important basis for strategies to interfere with biofilm formation in the environment and human disease. PMID:22232686
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Effects of Hydrogen Peroxide on Dental Unit Biofilms and Treatment Water Contamination
Lin, Shih-Ming; Svoboda, Kathy K.H.; Giletto, Anthony; Seibert, Jeff; Puttaiah, Raghunath
2011-01-01
Objectives: To study effects of various concentrations of hydrogen peroxide on mature waterline biofilms and in controlling planktonic (free-floating) organisms in simulated dental treatment water systems; and to study in vitro the effects of 2%, 3%, and 7% hydrogen peroxide on the removal of mature biofilms and inorganic compounds in dental waterlines. Methods: Four units of an automated dental unit water system simulation device was used for 12 weeks. All units were initially cleaned to control biofilms and inorganic deposits. H2O2 at concentrations of 1%, 2%, 3% was used weekly for periodic cleaning in three treatment group units (units 1, 2 & 3), with 0.05%, 0.15% and 0.25% H2O2 in municipal water used as irrigant respectively. The control unit (unit 4) did not have weekly cleanings and used municipal water as irrigant. Laser Scanning Confocal Microscopy and Scanning Electron Microscopy were used to study deposits on lines, and weekly heterotrophic plate counts done to study effluent water contamination. A 24 hour in vitro challenge test with 7%, 3% and 2% H2O2 on mature biofilms was conducted using harvested waterlines to study biofilm and inorganic deposit removal. Results: Heterotrophic plate counts of effluent water showed that the control unit reached contamination levels in excess of 400,000 CFU/mL while all treatment units showed contamination levels <500 CFU/mL through most of the 12 weeks. All treatment units showed varying levels of biofilm and inorganic deposit control in this short 12 week study. The in vitro challenge test showed although there was biofilm control, there was no eradication even when 7% H2O2 was used for 24 hours. Conclusions: 2% H2O2 used as a periodic cleaner, and diluted to 0.05% in municipal water for irrigation was beneficial in controlling biofilm and planktonic contamination in dental unit water systems. However, to remove well established biofilms, it may take more than 2 months when initial and multiple periodic cleanings
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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.
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Shao, Jing; Lu, KeQiao; Tian, Ge; Cui, YanYan; Yan, YuanYuan; Wang, TianMing; Zhang, XinLong; Wang, ChangZhong
2015-02-01
The assembly of a man-made gravity-supported free-flow biofilm incubator (GS-FFBI) was described, which was composed of a gas cushion injector and four incubators. The GS-FFBI had the characteristics of (i) a bottom-up flow direction, and (ii) lab-scale biofilm preparation without the use of a multichannel pump. Two opportunistic fungal strains, namely Candida albicans and Candida glabrata, were employed to incubate C. albicans and dual C. albicans-C. glabrata biofilms on the surface of medical-grade polyvinyl chloride perfusion tube. In terms of the results from {2, 3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide} (XTT) assay, dry weight measurement, colony-forming unit counting, susceptibility test, and scanning electron microscopy, it was demonstrated that GS-FFBI could form both stable single and dual Candida biofilms with no significant variations among the four incubators or the three daily incubations within 21h, and could operate for at least 96h smoothly with no contamination of stock medium. The results also indicated, for the first time, that C. albicans and C. glabrata might be co-existent competitively and symbiotically in the dual biofilms with flowing media. GS-FFBI would be a useful device to study in vitro morphological and physiological features of microbial biofilms in the medical settings. Copyright © 2014 Elsevier B.V. All rights reserved.
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Babauta, Jerome T; Nguyen, Hung Duc; Harrington, Timothy D; Renslow, Ryan; Beyenal, Haluk
2012-10-01
The limitation of pH inside electrode-respiring biofilms is a well-known concept. However, little is known about how pH and redox potential are affected by increasing current inside biofilms respiring on electrodes. Quantifying the variations in pH and redox potential with increasing current is needed to determine how electron transfer is tied to proton transfer within the biofilm. In this research, we quantified pH and redox potential variations in electrode-respiring Geobacter sulfurreducens biofilms as a function of respiration rates, measured as current. We also characterized pH and redox potential at the counter electrode. We concluded that (1) pH continued to decrease in the biofilm through different growth phases, showing that the pH is not always a limiting factor in a biofilm and (2) decreasing pH and increasing redox potential at the biofilm electrode were associated only with the biofilm, demonstrating that G. sulfurreducens biofilms respire in a unique internal environment. Redox potential inside the biofilm was also compared to the local biofilm potential measured by a graphite microelectrode, where the tip of the microelectrode was allowed to acclimatize inside the biofilm. Copyright © 2012 Wiley Periodicals, Inc.
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Piletska, Elena V; Stavroulakis, Georgios; Larcombe, Lee D; Whitcombe, Michael J; Sharma, Anant; Primrose, Sandy; Robinson, Gary K; Piletsky, Sergey A
2011-04-11
Here we present the first molecular imprinted polymer (MIP) that is able to attenuate the biofilm formation of the opportunistic human pathogen Pseudomonas aeruginosa through specific sequestration of its signal molecule N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C(12)-AHL). The MIP was rationally designed using computational modeling, and its capacity and specificity and that of a corresponding blank polymer toward signal molecule of P. aeruginosa (3-oxo-C(12)-AHL) and its analogue were tested. The biofilm formation in the presence of polymers and without polymers was studied using scanning confocal laser microscopy. Staining with crystal violet dye was used for the quantification of the biofilm formation. A significant reduction of the biofilm growth was observed in the presence of MIP (>80%), which was superior to that of the resin prepared without template, which showed a reduction of 40% in comparison with biofilm, which was grown without polymer addition. It was shown that 3-oxo-C(12)-AHL-specific MIP prevented the development of quorum-sensing-controlled phenotypes (in this case, biofilm formation) from being up-regulated. The developed MIP could be considered as a new tool for the elimination of life-threatening infections in a multitude of practical applications; it could, for example, be grafted on the surface of medical devices such as catheters and lenses, be a component of paints, or be used as a wound adsorbent.
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Spatial Patterns of Carbonate Biomineralization in Biofilms
Li, Xiaobao; Chopp, David L.; Russin, William A.; Brannon, Paul T.; Parsek, Matthew R.
2015-01-01
Microbially catalyzed precipitation of carbonate minerals is an important process in diverse biological, geological, and engineered systems. However, the processes that regulate carbonate biomineralization and their impacts on biofilms are largely unexplored, mainly because of the inability of current methods to directly observe biomineralization within biofilms. Here, we present a method for in situ, real-time imaging of biomineralization in biofilms and use it to show that Pseudomonas aeruginosa biofilms produce morphologically distinct carbonate deposits that substantially modify biofilm structures. The patterns of carbonate biomineralization produced in situ were substantially different from those caused by accumulation of particles produced by abiotic precipitation. Contrary to the common expectation that mineral precipitation should occur at the biofilm surface, we found that biomineralization started at the base of the biofilm. The carbonate deposits grew over time, detaching biofilm-resident cells and deforming the biofilm morphology. These findings indicate that biomineralization is a general regulator of biofilm architecture and properties. PMID:26276112
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Cleaning and Disinfection of Bacillus cereus Biofilm.
Deal, Amanda; Klein, Dan; Lopolito, Paul; Schwarz, John Spencer
2016-01-01
Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to disassociated B. cereus spores and biofilm from a non-spore-forming species. Further, we assessed the impact that pre-cleaning has on increasing that susceptibility. Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to
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NASA Astrophysics Data System (ADS)
Suzuki, Luis Cláudio; Araujo Prates, Renato; Raele, Marcus Paulo; Zanardi di Freitas, Anderson; Simões Ribeiro, Martha
2010-04-01
The biofilm formed by Candida albicans is the mainly cause of infections associated to medical devices such as catheters. Studies have shown that photodynamic antimicrobial therapy (PAT) has lethal effect on C. albicans, and it is based on photosensitizer (PS) in the presence of low intensity light to generate reactive oxygen species in biological systems. The aim of this study was to analyze in real time, by Optical Coherence Tomography (OCT), the alterations in C. albicans biofilm in vitro during PAT using methylene blue (MB) as a PS and red light. An OCT system with working at 930nm was used, sequential images of 2000×512 pixels were generated at the frame rate of 2.5frames/sec. The dimension of the analyzed sample was 6000μm wide by 1170μm of depth corrected by refraction index of 1.35. We recorded 1min. before and after the irradiation with LED for PAT, generating 8min. of video. For biofilm formation, discs were made from elastomeric silicone catheters. The PS was dissolved in PBS solution, and a final concentration of 1mM MB was applied on biofilm, followed by a red LED irradiation (λ=630nm+/-20nm) during 6min. We performed a curve of survival fraction versus time of irradiation and it was reduced by 100% following 6min. of irradiation. OCT was performed for measurement of biofilm thickness of 110μm when biofilm was formed. During irradiation, the variation of biofilm thickness was ~70μm. We conclude that OCT system is able to show real time optical changes provided by PAT in yeasts organized in biofilm.
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Diffusion in biofilms respiring on electrodes
DOE Office of Scientific and Technical Information (OSTI.GOV)
Renslow, Ryan S.; Babauta, Jerome T.; Majors, Paul D.
2012-11-15
The goal of this study was to measure spatially and temporally resolved effective diffusion coefficients (De) in biofilms respiring on electrodes. Two model electrochemically active biofilms, Geobacter sulfurreducens PCA and Shewanella oneidensis MR-1, were investigated. A novel nuclear magnetic resonance microimaging perfusion probe capable of simultaneous electrochemical and pulsed-field gradient nuclear magnetic resonance (PFG-NMR) techniques was used. PFG-NMR allowed for noninvasive, nondestructive, high spatial resolution in situ De measurements in living biofilms respiring on electrodes. The electrodes were polarized so that they would act as the sole terminal electron acceptor for microbial metabolism. We present our results as both two-dimensionalmore » De heat maps and surface-averaged relative effective diffusion coefficient (Drs) depth profiles. We found that (1) Drs decreases with depth in G. sulfurreducens biofilms, following a sigmoid shape; (2) Drs at a given location decreases with G. sulfurreducens biofilm age; (3) average De and Drs profiles in G. sulfurreducens biofilms are lower than those in S. oneidensis biofilms—the G. sulfurreducens biofilms studied here were on average 10 times denser than the S. oneidensis biofilms; and (4) halting the respiration of a G. sulfurreducens biofilm decreases the De values. Density, reflected by De, plays a major role in the extracellular electron transfer strategies of electrochemically active biofilms.« less
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Shen, Yun; Monroy, Guillermo L; Derlon, Nicolas; Janjaroen, Dao; Huang, Conghui; Morgenroth, Eberhard; Boppart, Stephen A; Ashbolt, Nicholas J; Liu, Wen-Tso; Nguyen, Thanh H
2015-04-07
Biofilms in drinking water distribution systems (DWDS) could exacerbate the persistence and associated risks of pathogenic Legionella pneumophila (L. pneumophila), thus raising human health concerns. However, mechanisms controlling adhesion and subsequent detachment of L. pneumophila associated with biofilms remain unclear. We determined the connection between L. pneumophila adhesion and subsequent detachment with biofilm physical structure characterization using optical coherence tomography (OCT) imaging technique. Analysis of the OCT images of multispecies biofilms grown under low nutrient condition up to 34 weeks revealed the lack of biofilm deformation even when these biofilms were exposed to flow velocity of 0.7 m/s, typical flow for DWDS. L. pneumophila adhesion on these biofilm under low flow velocity (0.007 m/s) positively correlated with biofilm roughness due to enlarged biofilm surface area and local flow conditions created by roughness asperities. The preadhered L. pneumophila on selected rough and smooth biofilms were found to detach when these biofilms were subjected to higher flow velocity. At the flow velocity of 0.1 and 0.3 m/s, the ratio of detached cell from the smooth biofilm surface was from 1.3 to 1.4 times higher than that from the rough biofilm surface, presumably because of the low shear stress zones near roughness asperities. This study determined that physical structure and local hydrodynamics control L. pneumophila adhesion to and detachment from simulated drinking water biofilm, thus it is the first step toward reducing the risk of L. pneumophila exposure and subsequent infections.
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Maharjan, Pramir; Huff, Geraldine; Zhang, Wen; Watkins, Susan
2017-01-01
An in vitro experiment was conducted to understand the nature of biofilm growth on polyvinyl chloride (PVC) surface when exposed to suboptimal-quality microbial water (>4 log 10 cfu/mL) obtained from a poultry drinking water source mimicking water in waterlines during the first week of poultry brooding condition. PVC sections (internal surface area of 15.16 cm 2 ) were utilized in the study to grow biofilm. After a 7-d test period, test coupons with 7-day-old biofilm were transferred into autoclaved municipal water and then treated with either chlorine-based or hydrogen peroxide-based sanitizer at bird drinking water rate, to see the impact on removal of biofilm formed on test coupons. Two trials (T1 and T2) were conducted. Test coupons used in T1 and T2 had the bacterial growth of 3.67 (SEM 0.04) and 3.97 (SEM 0.11) log 10 cfu/cm 2 on d 7. After sanitizer application, chlorine-based sanitizer removed bacteria in biofilm completely (0 cfu/cm 2 ) within 24 h post treatment whereas hydrogen peroxide-based sanitizer reduced the counts to 1.68 log 10 cfu/cm 2 (P < 0.05) by 48 h post sanitizer application. Control remained the same (P > 0.05). Results indicated that biofilm formation can occur quickly under suboptimal water condition on PVC surface, and sanitizer application helped mitigate already formed biofilm, yet chlorine proved to be more effective than hydrogen peroxide. © 2016 Poultry Science Association Inc.
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A personal history of research on microbial biofilms and biofilm infections.
Høiby, Niels
2014-04-01
The observation of aggregated microorganisms surrounded by a self-produced matrix adhering to surfaces or located in tissues or secretions is as old as microbiology, with both Leeuwenhoek and Pasteur describing the phenomenon. In environmental and technical microbiology, biofilms were already shown 80-90 years ago to be important for biofouling on submerged surfaces, e.g. ships. The concept of biofilm infections and their importance in medicine is, however, < 40 years old and was started by Jendresen's observations of acquired dental pellicles and my own observations of heaps of Pseudomonas aeruginosa cells in sputum and lung tissue from chronically infected cystic fibrosis patients. The term biofilm was introduced into medicine in 1985 by Costerton. In the following decades, it became obvious that biofilm infections are widespread in medicine, and their importance is now generally accepted. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.
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The membrane biofilm reactor: the natural partnership of membranes and biofilm.
Rittmann, B E
2006-01-01
Many exciting new technologies for water-quality control combine microbiological processes with adsorption, advanced oxidation, a membrane or an electrode to improve performance, address emerging contaminants or capture renewable energy. An excellent example is the H2-based membrane biofilm reactor (MBfR), which delivers H2 gas to a biofilm that naturally accumulates on the outer surface of a bubbleless membrane. Autotrophic bacteria in the biofilm oxidise the H2 and use the electrons to reduce NO3-, CIO4- and other oxidised contaminants. This natural partnership of membranes and biofilm makes it possible to gain many cost, performance and simplicity advantages from using H2 as the electron donor for microbially catalysed reductions. The MBfR has been demonstrated for denitrification in drinking water; reduction of perchlorate in groundwater; reduction of selenate, chromate, trichloroethene and other emerging contaminants; advanced N removal in wastewater treatment and autotrophic total-N removal.
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Efficacy of NVC-422 against Staphylococcus aureus biofilms in a sheep biofilm model of sinusitis.
Singhal, Deepti; Jekle, Andreas; Debabov, Dmitri; Wang, Lu; Khosrovi, Bez; Anderson, Mark; Foreman, Andrew; Wormald, Peter-John
2012-01-01
Bacterial biofilms are a major obstacle in management of recalcitrant chronic rhinosinusitis. NVC-422 is a potent, fast-acting, broad-spectrum, nonantibiotic, antimicrobial with a new mechanism of action effective against biofilm bacteria in in vitro conditions. The aim of this study was to investigate the safety and efficacy of NVC-422 as local antibiofilm treatment in a sheep model of rhinosinusitis. After accessing and occluding frontal sinus ostia in 24 merino sheep via staged endoscopic procedures, S. aureus clinical isolate was instilled in frontal sinuses. Following biofilm formation, ostial obstruction was removed and sinuses irrigated with 0.1% and 0.5% NVC-422 in 5 mM acetate isotonic saline at pH 4.0. Sheep were monitored for adverse effects and euthanized 24 hours after treatment. Frontal sinuses were assessed for infection and changes in mucosa after the treatment. S. aureus biofilms were identified with Baclight-confocal scanning microscopy protocol and the biofilm biomass assayed by applying the COMSTAT2 program to recorded image stacks. After 2 irrigations with 0.1% NVC-422, S. aureus biofilm biomass was reduced when compared to control sinuses (p = 0.0001), though this effect was variable in samples. NVC-422 0.5% solution irrigations reduced biofilm even more significantly and consistently over all samples (p < 0.0001). NVC-422 0.5% was also more effective than 0.1% NVC-422, vehicle control, and normal saline sinus irrigations in reducing biofilm biomass (p < 0.05 for all subgroups). No adverse events were observed in sheep after sinus irrigations with 0.1% and 0.5% NVC-422 solutions. NVC-422 is an effective topical agent against S. aureus biofilms, with dose-dependent efficacy in this animal model of biofilm-associated sinusitis. Copyright © 2012 American Rhinologic Society-American Academy of Otolaryngic Allergy, LLC.
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Ultraviolet-Absorption Spectroscopic Biofilm Monitor
NASA Technical Reports Server (NTRS)
Micheels, Ronald H.
2004-01-01
An ultraviolet-absorption spectrometer system has been developed as a prototype instrument to be used in continuous, real-time monitoring to detect the growth of biofilms. Such monitoring is desirable because biofilms are often harmful. For example, biofilms in potable-water and hydroponic systems act as both sources of pathogenic bacteria that resist biocides and as a mechanism for deterioration (including corrosion) of pipes. Biofilms formed from several types of hazardous bacteria can thrive in both plant-growth solutions and low-nutrient media like distilled water. Biofilms can also form in condensate tanks in air-conditioning systems and in industrial heat exchangers. At present, bacteria in potable-water and plant-growth systems aboard the space shuttle (and previously on the Mir space station) are monitored by culture-plate counting, which entails an incubation period of 24 to 48 hours for each sample. At present, there are no commercially available instruments for continuous monitoring of biofilms in terrestrial or spaceborne settings.
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A Sub-microsecond Pulsed Plasma Jet for Endodontic Biofilm Disinfection
NASA Astrophysics Data System (ADS)
Jiang, Chunqi; Schaudinn, Christoph; Jaramillo, David E.; Gundersen, Martin A.; Costerton, J. William
A pulsed, tapered cylindrical plasma jet, several centimeter long and <2 mm in diameter, has been generated by a concentric tubular device for root canal disinfection. This plasma dental probe is typically powered with ˜100 ns, 1 kHz, multi-kilovolt electric pulses and filled with 5 SLPM (standard liter per minute) He/(1%)O2 flow. We report here an in vitro study of the antimicrobial effect of the room temperature plasma jet against monolayer Enterococcus faecalis biofilms on bovine dentins. Resultant colony-forming unit counts were associated with changes in bacterial cell morphology observed using scanning electron microscopy (SEM) following the treatment and control. Treatment of dentin discs cultivated with E. faecalis monolayer biofilms with the plasma (average power ≈ 1 W) for 5 min resulted in 92.4% kill (P < 0.0001). Severe disruption of the cell membranes was observed for the plasma treatment group, while the morphology of the cells remained intact for the negative control group. In addition, a pilot ex vivo test was conducted to examine the bactericidal effect of the plasma against saliva-derived biofilms cultivated in human root canals. Conspicuous biofilm disruption and cleared dentinal surfaces were observed in the canal after the plasma treatment for 5 min. We conclude that this non-thermal pulsed plasma-based technology is a potential alternative or supplement to existing protocols for root canal disinfection.
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Pandit, S; Cai, J N; Song, K Y; Jeon, J G
2015-08-01
The aim of this study was to identify components of the Withania somnifera that could show anti-virulence activity against Streptococcus mutans biofilms. The anti-acidogenic activity of fractions separated from W. somnifera was compared, and then the most active anti-acidogenic fraction was chemically characterized using gas chromatography-mass spectroscopy. The effect of the identified components on the acidogenicity, aciduricity and extracellular polymeric substances (EPS) formation of S. mutans UA159 biofilms was evaluated. The change in accumulation and acidogenicity of S. mutans UA159 biofilms by periodic treatments (10 min per treatment) with the identified components was also investigated. Of the fractions, n-hexane fraction showed the strongest anti-acidogenic activity and was mainly composed of palmitic, linoleic and oleic acids. Of the identified components, linoleic and oleic acids strongly affected the acid production rate, F-ATPase activity and EPS formation of the biofilms. Periodic treatment with linoleic and oleic acids during biofilm formation also inhibited the biofilm accumulation and acid production rate of the biofilms without killing the biofilm bacteria. These results suggest that linoleic and oleic acids may be effective agents for restraining virulence of S. mutans biofilms. Linoleic and oleic acids may be promising agents for controlling virulence of cariogenic biofilms and subsequent dental caries formation. © 2015 The Society for Applied Microbiology.
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Biofilm Surface Density Determines Biocide Effectiveness
Bas, Sara; Kramer, Mateja; Stopar, David
2017-01-01
High resistance of biofilms for chemical challenges is a serious industrial and medical problem. In this work a gradient of surface covered with biofilm has been produced and correlated to the effectiveness of different commercially available oxidative biocides. The results for thin Escherichia coli biofilms grown in rich media supplemented with glucose or lactose on glass or poly methyl methacrylate surfaces indicate that the effectiveness of hydrogen peroxide or chlorine dioxide and quaternary ammonium compounds is inversely proportional to the fraction of the surface covered with the biofilm. In areas where biofilm covered more than 90% of the available surface the biocide treatment was inefficient after 60 min of incubation. The combined effect of oxidant and surfactant increased the effectiveness of the biocide. On the other hand, the increased biofilm viscoelasticity reduced biocide effectiveness. The results emphasize differential biocide effectiveness depending on the fraction of the attached bacterial cells. The results suggest that biofilm biocide resistance is an acquired property that increases with biofilm maturation. The more dense sessile structures present lower log reductions compared to less dense ones. PMID:29276508
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From biofilm ecology to reactors: a focused review.
Boltz, Joshua P; Smets, Barth F; Rittmann, Bruce E; van Loosdrecht, Mark C M; Morgenroth, Eberhard; Daigger, Glen T
2017-04-01
Biofilms are complex biostructures that appear on all surfaces that are regularly in contact with water. They are structurally complex, dynamic systems with attributes of primordial multicellular organisms and multifaceted ecosystems. The presence of biofilms may have a negative impact on the performance of various systems, but they can also be used beneficially for the treatment of water (defined herein as potable water, municipal and industrial wastewater, fresh/brackish/salt water bodies, groundwater) as well as in water stream-based biological resource recovery systems. This review addresses the following three topics: (1) biofilm ecology, (2) biofilm reactor technology and design, and (3) biofilm modeling. In so doing, it addresses the processes occurring in the biofilm, and how these affect and are affected by the broader biofilm system. The symphonic application of a suite of biological methods has led to significant advances in the understanding of biofilm ecology. New metabolic pathways, such as anaerobic ammonium oxidation (anammox) or complete ammonium oxidation (comammox) were first observed in biofilm reactors. The functions, properties, and constituents of the biofilm extracellular polymeric substance matrix are somewhat known, but their exact composition and role in the microbial conversion kinetics and biochemical transformations are still to be resolved. Biofilm grown microorganisms may contribute to increased metabolism of micro-pollutants. Several types of biofilm reactors have been used for water treatment, with current focus on moving bed biofilm reactors, integrated fixed-film activated sludge, membrane-supported biofilm reactors, and granular sludge processes. The control and/or beneficial use of biofilms in membrane processes is advancing. Biofilm models have become essential tools for fundamental biofilm research and biofilm reactor engineering and design. At the same time, the divergence between biofilm modeling and biofilm reactor
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Ausbacher, D; Lorenz, L; Pitts, B; Stewart, P S; Goeres, D M
2018-03-01
Biofilms are microbial aggregates that show high tolerance to antibiotic treatments in vitro and in vivo. Killing and removal are both important in biofilm control, therefore methods that measure these two mechanisms were evaluated in a parallel experimental design. Kill was measured using the single tube method (ASTM method E2871) and removal was determined by video microscopy and image analysis using a new treatment flow cell. The advantage of the parallel test design is that both methods used biofilm covered coupons harvested from a CDC biofilm reactor, a well-established and standardized biofilm growth method. The control Staphylococcus aureus biofilms treated with growth medium increased by 0·6 logs during a 3-h contact time. Efficacy testing showed biofilms exposed to 400 μmol l -1 penicillin G decreased by only 0·3 logs. Interestingly, time-lapse confocal scanning laser microscopy revealed that penicillin G treatment dispersed the biofilm despite being an ineffective killing agent. In addition, no biofilm removal was detected when assays were performed in 96-well plates. These results illustrate that biofilm behaviour and impact of treatments can vary substantially when assayed by different methods. Measuring both killing and removal with well-characterized methods will be crucial for the discovery of new anti-biofilm strategies. Biofilms are tolerant to antimicrobial treatments and can lead to persistent infections. Finding new anti-biofilm strategies and understanding their mode-of-action is therefore of high importance. Historically, antimicrobial testing has focused on measuring the decrease in viability. While kill data are undeniably important, measuring biofilm disruption provides equally useful information. Starting with biofilm grown in the same reactor, we paired assessment of biofilm removal using a new treatment-flow-cell and real-time microscopy with kill data collected using the single tube method (ASTM E2871). Pairing these two methods
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Solid-state NMR for bacterial biofilms
NASA Astrophysics Data System (ADS)
Reichhardt, Courtney; Cegelski, Lynette
2014-04-01
Bacteria associate with surfaces and one another by elaborating an extracellular matrix to encapsulate cells, creating communities termed biofilms. Biofilms are beneficial in some ecological niches, but also contribute to the pathogenesis of serious and chronic infectious diseases. New approaches and quantitative measurements are needed to define the composition and architecture of bacterial biofilms to help drive the development of strategies to interfere with biofilm assembly. Solid-state nuclear magnetic resonance (NMR) is uniquely suited to the examination of insoluble and complex macromolecular and whole-cell systems. This article highlights three examples that implement solid-state NMR to deliver insights into bacterial biofilm composition and changes in cell-wall composition as cells transition to the biofilm lifestyle. Most recently, solid-state NMR measurements provided a total accounting of the protein and polysaccharide components in the extracellular matrix of an Escherichia coli biofilm and transformed our qualitative descriptions of matrix composition into chemical parameters that permit quantitative comparisons among samples. We present additional data for whole biofilm samples (cells plus the extracellular matrix) that complement matrix-only analyses. The study of bacterial biofilms by solid-state NMR is an exciting avenue ripe with many opportunities and we close the article by articulating some outstanding questions and future directions in this area.
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Inactivation of biofilm bacteria.
LeChevallier, M W; Cawthon, C D; Lee, R G
1988-01-01
The current project was developed to examine inactivation of biofilm bacteria and to characterize the interaction of biocides with pipe surfaces. Unattached bacteria were quite susceptible to the variety of disinfectants tested. Viable bacterial counts were reduced 99% by exposure to 0.08 mg of hypochlorous acid (pH 7.0) per liter (1 to 2 degrees C) for 1 min. For monochloramine, 94 mg/liter was required to kill 99% of the bacteria within 1 min. These results were consistent with those found by other investigators. Biofilm bacteria grown on the surfaces of granular activated carbon particles, metal coupons, or glass microscope slides were 150 to more than 3,000 times more resistant to hypochlorous acid (free chlorine, pH 7.0) than were unattached cells. In contrast, resistance of biofilm bacteria to monochloramine disinfection ranged from 2- to 100-fold more than that of unattached cells. The results suggested that, relative to inactivation of unattached bacteria, monochloramine was better able to penetrate and kill biofilm bacteria than free chlorine. For free chlorine, the data indicated that transport of the disinfectant into the biofilm was a major rate-limiting factor. Because of this phenomenon, increasing the level of free chlorine did not increase disinfection efficiency. Experiments where equal weights of disinfectants were used suggested that the greater penetrating power of monochloramine compensated for its limited disinfection activity. These studies showed that monochloramine was as effective as free chlorine for inactivation of biofilm bacteria. The research provides important insights into strategies for control of biofilm bacteria. Images PMID:2849380
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Biofilm models of polymicrobial infection.
Gabrilska, Rebecca A; Rumbaugh, Kendra P
2015-01-01
Interactions between microbes are complex and play an important role in the pathogenesis of infections. These interactions can range from fierce competition for nutrients and niches to highly evolved cooperative mechanisms between different species that support their mutual growth. An increasing appreciation for these interactions, and desire to uncover the mechanisms that govern them, has resulted in a shift from monomicrobial to polymicrobial biofilm studies in different disease models. Here we provide an overview of biofilm models used to study select polymicrobial infections and highlight the impact that the interactions between microbes within these biofilms have on disease progression. Notable recent advances in the development of polymicrobial biofilm-associated infection models and challenges facing the study of polymicrobial biofilms are addressed.
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Biofilm models of polymicrobial infection
Gabrilska, Rebecca A; Rumbaugh, Kendra P
2015-01-01
Interactions between microbes are complex and play an important role in the pathogenesis of infections. These interactions can range from fierce competition for nutrients and niches to highly evolved cooperative mechanisms between different species that support their mutual growth. An increasing appreciation for these interactions, and desire to uncover the mechanisms that govern them, has resulted in a shift from monomicrobial to polymicrobial biofilm studies in different disease models. Here we provide an overview of biofilm models used to study select polymicrobial infections and highlight the impact that the interactions between microbes within these biofilms have on disease progression. Notable recent advances in the development of polymicrobial biofilm-associated infection models and challenges facing the study of polymicrobial biofilms are addressed. PMID:26592098
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Nadell, Carey D; Ricaurte, Deirdre; Yan, Jing; Drescher, Knut; Bassler, Bonnie L
2017-01-13
Bacteria often live in biofilms, which are microbial communities surrounded by a secreted extracellular matrix. Here, we demonstrate that hydrodynamic flow and matrix organization interact to shape competitive dynamics in Pseudomonas aeruginosa biofilms. Irrespective of initial frequency, in competition with matrix mutants, wild-type cells always increase in relative abundance in planar microfluidic devices under simple flow regimes. By contrast, in microenvironments with complex, irregular flow profiles - which are common in natural environments - wild-type matrix-producing and isogenic non-producing strains can coexist. This result stems from local obstruction of flow by wild-type matrix producers, which generates regions of near-zero shear that allow matrix mutants to locally accumulate. Our findings connect the evolutionary stability of matrix production with the hydrodynamics and spatial structure of the surrounding environment, providing a potential explanation for the variation in biofilm matrix secretion observed among bacteria in natural environments.
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Baudin, Marine; Cinquin, Bertrand; Sclavi, Bianca; Pareau, Dominique; Lopes, Filipa
2017-09-01
Confocal laser scanning microscopy (CLSM) is one of the most relevant technologies for studying biofilms in situ. Several tools have been developed to investigate and quantify the architecture of biofilms. However, an approach to quantify correctly the evolution of intensity of a fluorescent signal as a function of the structural parameters of a biofilm is still lacking. Here we present a tool developed in the ImageJ open source software that can be used to extract both structural and fluorescence intensity from CLSM data: BIAM (Biofilm Intensity and Architecture Measurement). This is of utmost significance when studying the fundamental mechanisms of biofilm growth, differentiation and development or when aiming to understand the effect of external molecules on biofilm phenotypes. In order to provide an example of the potential of such a tool in this study we focused on biofilm dispersion. cis-2-Decenoic acid (CDA) is a molecule known to induce biofilm dispersion of multiple bacterial species. The mechanisms by which CDA induces dispersion are still poorly understood. To investigate the effects of CDA on biofilms, we used a reporter strain of Escherichia coli (E. coli) that expresses the GFPmut2 protein under control of the rrnBP1 promoter. Experiments were done in flow cells and image acquisition was made with CLSM. Analysis carried out using the new tool, BIAM, indicates that CDA affects the fluorescence intensity of the biofilm structures as well as biofilm architectures. Indeed, our results demonstrate that CDA removes more than 35% of biofilm biovolume and suggest that it results in an increase of the biofilm's mean fluorescence intensity (MFI) by more than 26% compared to the control biofilm in the absence of CDA. Copyright © 2017. Published by Elsevier B.V.
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Zhu, Yan; Zhang, Yan; Ren, Hong-Qiang; Geng, Jin-Ju; Xu, Ke; Huang, Hui; Ding, Li-Li
2015-03-01
This study aimed to investigate biofilm properties evolution coupled with different ages during the start-up period in a moving bed biofilm reactor system. Physicochemical characteristics including adhesion force, extracellular polymeric substances (EPS), morphology as well as volatile solid and microbial community were studied. Results showed that the formation and development of biofilms exhibited four stages, including (I) initial attachment and young biofilm formation, (II) biofilms accumulation, (III) biofilm sloughing and updating, and (IV) biofilm maturation. During the whole start-up period, adhesion force was positively and significantly correlated with the contents of EPS, especially the content of polysaccharide. In addition, increased adhesion force and EPS were beneficial for biofilm retention. Gram-negative bacteria mainly including Sphaerotilus, Zoogloea and Haliscomenobacter were predominant in the initial stage. Actinobacteria was beneficial to resist sloughing. Furthermore, filamentous bacteria were dominant in maturation biofilm. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Sagripanti, J L; Bonifacino, A
2000-01-01
A comparison was made of the effectiveness of popular disinfectants (Cavicide, Cidexplus, Clorox, Exspor, Lysol, Renalin, and Wavicide) under conditions prescribed for disinfection in the respective product labels on Pseudomonas aeruginosa either in suspension or deposited onto surfaces of metallic or polymeric plastic devices. The testing also included 7 nonformulated germicidal agents (glutaraldehyde, formaldehyde, peracetic acid, hydrogen peroxide, sodium hypochlorite, phenol, and cupric ascorbate) commonly used in disinfection and decontamination. Results showed that P. aeruginosa is on average 300-fold more resistant when present on contaminated surfaces than in suspension. This increase in resistance agrees with results reported in studies of biofilms, but unexpectedly, it precedes biofilm formation. The surface to which bacteria are attached can influence the effectiveness of disinfectants. Viable bacteria attached to devices may require dislodging through more than a one-step method for detection. The data, obtained with a sensitive and quantitative test, suggest that disinfectants are less effective on contaminated surfaces than generally acknowledged.
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Tseng, Sung-Pin; Hung, Wei-Chun; Huang, Chiung-Yao; Lin, Yin-Shiou; Chan, Min-Yu; Lu, Po-Liang; Lin, Lin; Sheu, Jyh-Horng
2016-07-29
Nosocomial infections and increasing multi-drug resistance caused by Acinetobacter baumannii have been recognized as emerging problems worldwide. Moreover, A. baumannii is able to colonize various abiotic materials and medical devices, making it difficult to eradicate and leading to ventilator-associated pneumonia, and bacteremia. Development of novel molecules that inhibit bacterial biofilm formation may be an alternative prophylactic option for the treatment of biofilm-associated A. baumannii infections. Marine environments, which are unlike their terrestrial counterparts, harbor an abundant biodiversity of marine organisms that produce novel bioactive natural products with pharmaceutical potential. In this study, we identified 5-episinuleptolide, which was isolated from Sinularia leptoclados, as an inhibitor of biofilm formation in ATCC 19606 and three multi-drug resistant A. baumannii strains. In addition, the anti-biofilm activities of 5-episinuleptolide were observed for Gram-negative bacteria but not for Gram-positive bacteria, indicating that the inhibition mechanism of 5-episinuleptolide is effective against only Gram-negative bacteria. The mechanism of biofilm inhibition was demonstrated to correlate to decreased gene expression from the pgaABCD locus, which encodes the extracellular polysaccharide poly-β-(1,6)-N-acetylglucosamine (PNAG). Scanning electron microscopy (SEM) indicated that extracellular matrix of the biofilm was dramatically decreased by treatment with 5-episinuleptolide. Our study showed potentially synergistic activity of combination therapy with 5-episinuleptolide and levofloxacin against biofilm formation and biofilm cells. These data indicate that inhibition of biofilm formation via 5-episinuleptolide may represent another prophylactic option for solving the persistent problem of biofilm-associated A. baumannii infections.
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Metabolism links bacterial biofilms and colon carcinogenesis
Johnson, Caroline H.; Dejea, Christine M.; Edler, David; Hoang, Linh T.; Santidrian, Antonio F.; Felding, Brunhilde H.; Cho, Kevin; Wick, Elizabeth C.; Hechenbleikner, Elizabeth M.; Uritboonthai, Winnie; Goetz, Laura; Casero, Robert A.; Pardoll, Drew M.; White, James R.; Patti, Gary J.; Sears, Cynthia L.; Siuzdak, Gary
2015-01-01
SUMMARY Bacterial biofilms in the colon alter the host tissue microenvironment. A role for biofilms in colon cancer metabolism has been suggested but to date has not been evaluated. Using metabolomics, we investigated the metabolic influence that microbial biofilms have on colon tissues and the related occurrence of cancer. Patient-matched colon cancers and histologically normal tissues, with or without biofilms, were examined. We show the upregulation of polyamine metabolites in tissues from cancer hosts with significant enhancement of N1, N12-diacetylspermine in both biofilm positive cancer and normal tissues. Antibiotic treatment, which cleared biofilms, decreased N1, N12-diacetylspermine levels to those seen in biofilm negative tissues, indicating that host cancer and bacterial biofilm structures contribute to the polyamine metabolite pool. These results show that colonic mucosal biofilms alter the cancer metabolome, to produce a regulator of cellular proliferation and colon cancer growth potentially affecting cancer development and progression. PMID:25959674
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Metabolism links bacterial biofilms and colon carcinogenesis.
Johnson, Caroline H; Dejea, Christine M; Edler, David; Hoang, Linh T; Santidrian, Antonio F; Felding, Brunhilde H; Ivanisevic, Julijana; Cho, Kevin; Wick, Elizabeth C; Hechenbleikner, Elizabeth M; Uritboonthai, Winnie; Goetz, Laura; Casero, Robert A; Pardoll, Drew M; White, James R; Patti, Gary J; Sears, Cynthia L; Siuzdak, Gary
2015-06-02
Bacterial biofilms in the colon alter the host tissue microenvironment. A role for biofilms in colon cancer metabolism has been suggested but to date has not been evaluated. Using metabolomics, we investigated the metabolic influence that microbial biofilms have on colon tissues and the related occurrence of cancer. Patient-matched colon cancers and histologically normal tissues, with or without biofilms, were examined. We show the upregulation of polyamine metabolites in tissues from cancer hosts with significant enhancement of N(1), N(12)-diacetylspermine in both biofilm-positive cancer and normal tissues. Antibiotic treatment, which cleared biofilms, decreased N(1), N(12)-diacetylspermine levels to those seen in biofilm-negative tissues, indicating that host cancer and bacterial biofilm structures contribute to the polyamine metabolite pool. These results show that colonic mucosal biofilms alter the cancer metabolome to produce a regulator of cellular proliferation and colon cancer growth potentially affecting cancer development and progression. Copyright © 2015 Elsevier Inc. All rights reserved.
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Parker, Jennifer K; Chen, Hongyu; McCarty, Sara E; Liu, Lawrence Y; De La Fuente, Leonardo
2016-05-01
The functions of calcium (Ca) in bacteria are less characterized than in eukaryotes, where its role has been studied extensively. The plant-pathogenic bacterium Xylella fastidiosa has several virulence features that are enhanced by increased Ca concentrations, including biofilm formation. However, the specific mechanisms driving modulation of this feature are unclear. Characterization of biofilm formation over time showed that 4 mM Ca supplementation produced denser biofilms that were still developing at 96 h, while biofilm in non-supplemented media had reached the dispersal stage by 72 h. To identify changes in global gene expression in X. fastidiosa grown in supplemental Ca, RNA-Seq of batch culture biofilm cells was conducted at three 24-h time intervals. Results indicate that a variety of genes are differentially expressed in response to Ca, including genes related to attachment, motility, exopolysaccharide synthesis, biofilm formation, peptidoglycan synthesis, regulatory functions, iron homeostasis, and phages. Collectively, results demonstrate that Ca supplementation induces a transcriptional response that promotes continued biofilm development, while biofilm cells in nonsupplemented media are driven towards dispersion of cells from the biofilm structure. These results have important implications for disease progression in planta, where xylem sap is the source of Ca and other nutrients for X. fastidiosa. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.
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Ex vivo vs. in vivo antibacterial activity of two antiseptics on oral biofilm
Prada-López, Isabel; Quintas, Víctor; Casares-De-Cal, Maria A.; Suárez-Quintanilla, Juan A.; Suárez-Quintanilla, David; Tomás, Inmaculada
2015-01-01
Aim: To compare the immediate antibacterial effect of two application methods (passive immersion and active mouthwash) of two antiseptic solutions on the in situ oral biofilm. Material and Methods: A randomized observer-masked crossover study was conducted. Fifteen healthy volunteers wore a specific intraoral device for 48 h to form a biofilm in three glass disks. One of these disks was used as a baseline; another one was immersed in a solution of 0.2% Chlorhexidine (0.2% CHX), remaining the third in the device, placed in the oral cavity, during the 0.2% CHX mouthwash application. After a 2-weeks washout period, the protocol was repeated using a solution of Essential Oils (EO). Samples were analyzed for bacterial viability with the confocal laser scanning microscope after previous staining with LIVE/DEAD® BacLight™. Results: The EO showed a better antibacterial effect compared to the 0.2% CHX after the mouthwash application (% of bacterial viability = 1.16 ± 1.00% vs. 5.08 ± 5.79%, respectively), and was more effective in all layers (p < 0.05). In the immersion, both antiseptics were significantly less effective (% of bacterial viability = 26.93 ± 13.11%, EO vs. 15.17 ± 6.14%, 0.2% CHX); in the case of EO immersion, there were no significant changes in the bacterial viability of the deepest layer in comparison with the baseline. Conclusions: The method of application conditioned the antibacterial activity of the 0.2% CHX and EO solutions on the in situ oral biofilm. The in vivo active mouthwash was more effective than the ex vivo passive immersion in both antiseptic solutions. There was more penetration of the antiseptic inside the biofilm with an active mouthwash, especially with the EO. Trial registered in clinicaltrials.gov with the number NCT02267239. URL: https://clinicaltrials.gov/ct2/show/NCT02267239. PMID:26191050
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Brinkman, Cassandra L.; Schmidt-Malan, Suzannah M.; Karau, Melissa J.; Greenwood-Quaintance, Kerryl; Hassett, Daniel J.; Mandrekar, Jayawant N.
2016-01-01
Bacterial biofilms may form on indwelling medical devices such as prosthetic joints, heart valves and catheters, causing challenging-to-treat infections. We have previously described the ‘electricidal effect’, in which bacterial biofilms are decreased following exposure to direct electrical current. Herein, we sought to determine if the decreased bacterial quantities are due to detachment of biofilms or cell death and to investigate the role that reactive oxygen species (ROS) play in the observed effect. Using confocal and electron microscopy and flow cytometry, we found that direct current (DC) leads to cell death and changes in the architecture of biofilms formed by Gram-positive and Gram-negative bacteria. Reactive oxygen species (ROS) appear to play a role in DC-associated cell death, as there was an increase in ROS-production by Staphylococcus aureus and Staphylococcus epidermidis biofilms following exposure to DC. An increase in the production of ROS response enzymes catalase and superoxide dismutase (SOD) was observed for S. aureus, S. epidermidis and Pseudomonas aeruginosa biofilms following exposure to DC. Additionally, biofilms were protected from cell death when supplemented with antioxidants and oxidant scavengers, including catalase, mannitol and Tempol. Knocking out SOD (sodAB) in P. aeruginosa led to an enhanced DC effect. Microarray analysis of P. aeruginosa PAO1 showed transcriptional changes in genes related to the stress response and cell death. In conclusion, the electricidal effect results in death of bacteria in biofilms, mediated, at least in part, by production of ROS. PMID:27992529
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Brinkman, Cassandra L; Schmidt-Malan, Suzannah M; Karau, Melissa J; Greenwood-Quaintance, Kerryl; Hassett, Daniel J; Mandrekar, Jayawant N; Patel, Robin
2016-01-01
Bacterial biofilms may form on indwelling medical devices such as prosthetic joints, heart valves and catheters, causing challenging-to-treat infections. We have previously described the 'electricidal effect', in which bacterial biofilms are decreased following exposure to direct electrical current. Herein, we sought to determine if the decreased bacterial quantities are due to detachment of biofilms or cell death and to investigate the role that reactive oxygen species (ROS) play in the observed effect. Using confocal and electron microscopy and flow cytometry, we found that direct current (DC) leads to cell death and changes in the architecture of biofilms formed by Gram-positive and Gram-negative bacteria. Reactive oxygen species (ROS) appear to play a role in DC-associated cell death, as there was an increase in ROS-production by Staphylococcus aureus and Staphylococcus epidermidis biofilms following exposure to DC. An increase in the production of ROS response enzymes catalase and superoxide dismutase (SOD) was observed for S. aureus, S. epidermidis and Pseudomonas aeruginosa biofilms following exposure to DC. Additionally, biofilms were protected from cell death when supplemented with antioxidants and oxidant scavengers, including catalase, mannitol and Tempol. Knocking out SOD (sodAB) in P. aeruginosa led to an enhanced DC effect. Microarray analysis of P. aeruginosa PAO1 showed transcriptional changes in genes related to the stress response and cell death. In conclusion, the electricidal effect results in death of bacteria in biofilms, mediated, at least in part, by production of ROS.
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Thurnheer, Thomas; Belibasakis, Georgios N
2016-07-01
Staphylococcus spp. are postulated to play a role in peri-implantitis. This study aimed to develop a "submucosal" in vitro biofilm model, by integrating two staphylococci into its composition. The standard "subgingival" biofilm contained Actinomyces oris, Fusobacterium nucleatum, Streptococcus oralis, Veillonella dispar, Campylobacter rectus, Prevotella intermedia, Streptococcus anginosus, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola, and was further supplemented with Staphyoccous aureus and/or Staphylococcus epidermidis. Biofilms were grown anaerobically on hydroxyapatite or titanium discs and harvested after 64 h for real-time polymerase chain reaction, to determine their composition. Confocal laser scanning microscopy and fluorescence in situ hybridization were used for identifying the two staphylococci within the biofilm. Both staphylococci established within the biofilms when added separately. However, when added together, only S. aureus grew in high numbers, whereas S. epidermidis was reduced almost to the detection limit. Compared to the standard subgingival biofilm, addition of the two staphylococci had no impact on the qualitative or quantitative composition of the biofilm. When grown individually in the biofilm, S. epidermidis and S. aureus formed small distinctive clusters and it was confirmed that S. epidermidis was not able to grow in presence of S. aureus. Staphyoccous aureus and S. epidermidis can be individually integrated into an oral biofilm grown on titanium, hence establishing a "submucosal" biofilm model for peri-implantitis. This model also revealed that S. aureus outcompetes S. epidermidis when grown together in the biofilm, which may explain the more frequent association of the former with peri-implantitis. © 2015 The Authors. Clinical Oral Implants Research Published by John Wiley & Sons Ltd.
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Ma, Hongyan; Darmawan, Erica T.; Zhang, Min; Zhange, Lei; Bryers, James D.
2013-01-01
Traditional antibiotic therapy to control medical device-based infections typically fails to clear biofilm infections and may even promote the evolution of antibiotic resistant species. We report here the development of two novel antibiofilm agents; gallium (Ga) or zinc (Zn) complexed with protoporphyrin IX (PP) or mesoprotoporphyrin IX (MP) that are both highly effective in negating suspended bacterial growth and biofilm formation. These chelated gallium or zinc complexes act as iron siderophore analogs, surplanting the natural iron uptake of most bacteria. Poly (ether urethane) (PEU; Biospan®) polymer films were fabricated for the controlled sustained release of the Ga- or Zn-complexes, using an incorporated pore-forming agent, poly (ethylene glycol) (PEG). An optimum formulation containing 8% PEG (MW=1450) in the PEU polymer effectively sustained drug release for at least 3 months. All drug-loaded PEU films exhibited in vitro ≥ 90% reduction of Gram-positive (Staphylococcus epidermidis) and Gram-negative (Pseudomonas aeruginosa) bacteria in both suspended and biofilm culture versus the negative control PEU films releasing nothing. Cytotoxicity and endotoxin evaluation demonstrated no adverse responses to the Ga- or Zn-complex releasing PEU films. Finally, in vivo studies further substantiate the anti-biofilm efficacy of the PEU films releasing Ga- or Zn- complexes. PMID:24140747
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Ma, Hongyan; Darmawan, Erica T; Zhang, Min; Zhang, Lei; Bryers, James D
2013-12-28
Traditional antibiotic therapy to control medical device-based infections typically fails to clear biofilm infections and may even promote the evolution of antibiotic resistant species. We report here the development of two novel antibiofilm agents; gallium (Ga) or zinc (Zn) complexed with protoporphyrin IX (PP) or mesoprotoporphyrin IX (MP) that are both highly effective in negating suspended bacterial growth and biofilm formation. These chelated gallium or zinc complexes act as iron siderophore analogs, supplanting the natural iron uptake of most bacteria. Poly (ether urethane) (PEU; Biospan®) polymer films were fabricated for the controlled sustained release of the Ga- or Zn-complexes, using an incorporated pore-forming agent, poly(ethylene glycol) (PEG). An optimum formulation containing 8% PEG (MW=1450) in the PEU polymer effectively sustained drug release for at least 3months. All drug-loaded PEU films exhibited in vitro ≥ 90% reduction of Gram-positive (Staphylococcus epidermidis) and Gram-negative (Pseudomonas aeruginosa) bacteria in both suspended and biofilm culture versus the negative control PEU films releasing nothing. Cytotoxicity and endotoxin evaluation demonstrated no adverse responses to the Ga- or Zn-complex releasing PEU films. Finally, in vivo studies further substantiate the anti-biofilm efficacy of the PEU films releasing Ga- or Zn- complexes. © 2013.
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Extracellular DNA Contributes to Dental Biofilm Stability.
Schlafer, Sebastian; Meyer, Rikke L; Dige, Irene; Regina, Viduthalai R
2017-01-01
Extracellular DNA (eDNA) is a major matrix component of many bacterial biofilms. While the presence of eDNA and its role in biofilm stability have been demonstrated for several laboratory biofilms of oral bacteria, there is no data available on the presence and function of eDNA in in vivo grown dental biofilms. This study aimed to determine whether eDNA was part of the matrix in biofilms grown in situ in the absence of sucrose and whether treatment with DNase dispersed biofilms grown for 2.5, 5, 7.5, 16.5, or 24 h. Three hundred biofilms from 10 study participants were collected and treated with either DNase or heat-inactivated DNase for 1 h. The bacterial biovolume was determined with digital image analysis. Staining with TOTO®-1 allowed visualization of eDNA both on bacterial cell surfaces and, with a cloud-like appearance, in the intercellular space. DNase treatment strongly reduced the amount of biofilm in very early stages of growth (up to 7.5 h), but the treatment effect decreased with increasing biofilm age. This study proves the involvement of eDNA in dental biofilm formation and its importance for biofilm stability in the earliest stages. Further research is required to uncover the interplay of eDNA and other matrix components and to explore the therapeutic potential of DNase treatment for biofilm control. © 2017 S. Karger AG, Basel.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Yan, Zhifeng; Liu, Chongxuan; Liu, Yuanyuan
Biofilms are critical locations for biogeochemical reactions in the subsurface environment. The occurrence and distribution of biofilms at microscale as well as their impacts on macroscopic biogeochemical reaction rates are still poorly understood. This paper investigated the formation and distributions of biofilms in heterogeneous sediments using multiscale models, and evaluated the effects of biofilm heterogeneity on local and macroscopic biogeochemical reaction rates. Sediment pore structures derived from X-ray computed tomography were used to simulate the microscale flow dynamics and biofilm distribution in the sediment column. The response of biofilm formation and distribution to the variations in hydraulic and chemical propertiesmore » was first examined. One representative biofilm distribution was then utilized to evaluate its effects on macroscopic reaction rates using nitrate reduction as an example. The results revealed that microorganisms primarily grew on the surfaces of grains and aggregates near preferential flow paths where both electron donor and acceptor were readily accessible, leading to the heterogeneous distribution of biofilms in the sediments. The heterogeneous biofilm distribution decreased the macroscopic rate of biogeochemical reactions as compared with those in homogeneous cases. Operationally considering the heterogeneous biofilm distribution in macroscopic reactive transport models such as using dual porosity domain concept can significantly improve the prediction of biogeochemical reaction rates. Overall, this study provided important insights into the biofilm formation and distribution in soils and sediments as well as their impacts on the macroscopic manifestation of reaction rates.« less
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Acoustic vibration can enhance bacterial biofilm formation.
Murphy, Mark F; Edwards, Thomas; Hobbs, Glyn; Shepherd, Joanna; Bezombes, Frederic
2016-12-01
This paper explores the use of low-frequency-low-amplitude acoustic vibration on biofilm formation. Biofilm development is thought to be governed by a diverse range of environmental signals and much effort has gone into researching the effects of environmental factors including; nutrient availability, pH and temperature on the growth of biofilms. Many biofilm-forming organisms have evolved to thrive in mechanically challenging environments, for example soil yet, the effects of the physical environment on biofilm formation has been largely ignored. Exposure of Pseudomonas aeruginosa to vibration at 100, 800 and 1600 Hz for 48 h, resulted in a significant increase in biofilm formation compared with the control, with the greatest growth seen at 800 Hz vibration. The results also show that this increase in biofilm formation is accompanied with an increase in P. aeruginosa cell number. Acoustic vibration was also found to regulate the spatial distribution of biofilm formation in a frequency-dependent manner. Exposure of Staphylococcus aureus to acoustic vibration also resulted in enhanced biofilm formation with the greatest level of biofilm being formed following 48 h exposure at 1600 Hz. These results show that acoustic vibration can be used to control biofilm formation and therefore presents a novel and potentially cost effective means to manipulate the development and yield of biofilms in a range of important industrial and medical processes. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
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Dashper, Stuart G; Catmull, Deanne V; Liu, Sze-Wei; Myroforidis, Helen; Zalizniak, Ilya; Palamara, Joseph E A; Huq, N Laila; Reynolds, Eric C
2016-01-01
Glass ionomer cements (GIC) are dental restorative materials that are suitable for modification to help prevent dental plaque (biofilm) formation. The aim of this study was to determine the effects of incorporating casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) into a GIC on the colonisation and establishment of Streptococcus mutans biofilms and the effects of aqueous CPP-ACP on established S mutans biofilms. S. mutans biofilms were either established in flow cells before a single ten min exposure to 1% w/v CPP-ACP treatment or cultured in static wells or flow cells with either GIC or GIC containing 3% w/w CPP-ACP as the substratum. The biofilms were then visualised using confocal laser scanning microscopy after BacLight LIVE/DEAD staining. A significant decrease in biovolume and average thickness of S. mutans biofilms was observed in both static and flow cell assays when 3% CPP-ACP was incorporated into the GIC substratum. A single ten min treatment with aqueous 1% CPP-ACP resulted in a 58% decrease in biofilm biomass and thickness of established S. mutans biofilms grown in a flow cell. The treatment also significantly altered the structure of these biofilms compared with controls. The incorporation of 3% CPP-ACP into GIC significantly reduced S. mutans biofilm development indicating another potential anticariogenic mechanism of this material. Additionally aqueous CPP-ACP disrupted established S. mutans biofilms. The use of CPP-ACP containing GIC combined with regular CPP-ACP treatment may lower S. mutans challenge.
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Dranguet, P; Le Faucheur, S; Cosio, C; Slaveykova, V I
2017-01-25
Mercury (Hg) is a pollutant of high concern for aquatic systems due to the biomagnification of its methylated form along the food chain. However, in contrast to other metals, gaining knowledge of its bioavailable forms for aquatic microorganisms remains challenging, making Hg risk assessment difficult. Ubiquitous and sessile freshwater biofilms are well known to accumulate and to transform Hg present in their ambient environment. The present study thus aims to evaluate whether non-extractable (proxy of intracellular) Hg accumulated by biofilms could be a good indicator of Hg bioavailability for microorganisms in freshwater. To that end, the link between Hg concentration and speciation, as well as biofilm composition (percentage of abiotic, biotic, chlorophyll and phycocyanin-fractions and abundance of dsrA, gcs, merA and hgcA bacterial genes) and biofilm Hg accumulation was examined. The studied biofilms were grown on artificial substrata in four reservoirs along the Olt River (Romania), which was contaminated by Hg coming from chlor-alkali plant effluents. The 0.45 μm-filterable Hg concentrations in ambient waters were measured and inorganic IHg speciation was modelled. Biofilms were analyzed for their non-extractable IHg and methylmercury (MeHg) contents as well as for their composition. The non-extractable IHg content was related, but not significantly, to the concentration of total IHg (r 2 = 0.88, p = 0.061) whereas a significant correlation was found with the predicted IHg concentration that is not bound to dissolved organic matter (r 2 = 0.95, p = 0.027), despite its extremely low concentrations (10 -25 M), showing a limitation of the thermodynamic Hg modelling to predict Hg bioavailability. The studied biofilms were different in biomass and composition and a principal component analysis showed that the non-extractable IHg content correlated with the abundance of the merA and hgcA genes, while MeHg accumulation was only linked with the abundance of the r
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Dissipative-particle-dynamics model of biofilm growth
DOE Office of Scientific and Technical Information (OSTI.GOV)
Xu, Zhijie; Meakin, Paul; Tartakovsky, Alexandre M.
2011-06-13
A dissipative particle dynamics (DPD) model for the quantitative simulation of biofilm growth controlled by substrate (nutrient) consumption, advective and diffusive substrate transport, and hydrodynamic interactions with fluid flow (including fragmentation and reattachment) is described. The model was used to simulate biomass growth, decay, and spreading. It predicts how the biofilm morphology depends on flow conditions, biofilm growth kinetics, the rheomechanical properties of the biofilm and adhesion to solid surfaces. The morphology of the model biofilm depends strongly on its rigidity and the magnitude of the body force that drives the fluid over the biofilm.
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Plasticity of Candida albicans Biofilms
Daniels, Karla J.
2016-01-01
SUMMARY Candida albicans, the most pervasive fungal pathogen that colonizes humans, forms biofilms that are architecturally complex. They consist of a basal yeast cell polylayer and an upper region of hyphae encapsulated in extracellular matrix. However, biofilms formed in vitro vary as a result of the different conditions employed in models, the methods used to assess biofilm formation, strain differences, and, in a most dramatic fashion, the configuration of the mating type locus (MTL). Therefore, integrating data from different studies can lead to problems of interpretation if such variability is not taken into account. Here we review the conditions and factors that cause biofilm variation, with the goal of engendering awareness that more attention must be paid to the strains employed, the methods used to assess biofilm development, every aspect of the model employed, and the configuration of the MTL locus. We end by posing a set of questions that may be asked in comparing the results of different studies and developing protocols for new ones. This review should engender the notion that not all biofilms are created equal. PMID:27250770
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[The yeast biofilm in human medicine].
Růzicka, Filip; Holá, Veronika; Votava, Miroslav
2007-08-01
In recent years, the role of Candida yeasts as causative agents of nosocomial infections has increased. One of the important virulence factors contributing to the development of such infections is biofilm production. This virulence factor enables yeast to colonize both native surfaces and artificial implants. The most common sources of infection are patients themselves, in particular the gastrointestinal tract and skin. The vectors of exogenous yeast infections are predominantly the hands of the health personnel and contaminated medical instruments. The adhesion of yeasts to the implant surfaces is determined both by implant surface and yeast characteristics. This is followed by proliferation and production of microcolonies and extracellular matrix. The final biofilm structure is also influenced by the production of hyphae and pseudohyphae. The entire process of biofilm production is controlled by numerous regulatory systems, with the key role being played by the quorum sensing system. Like the adhered bacterial cultures, candidas growing in the form of a biofilm are highly resistant to antimicrobial therapy. Resistance of yeast biofilms to antifungals is a complex process with multiple contributing factors. These are especially increased gene expression (e.g. genes encoding the so called multidrug efflux pumps), limited penetration of substances through the extracellular matrix, inhibited cell growth and altered microenvironment in deeper biofilm layers. The concentrations of antifungals able to effectively affect the biofilm cells exceed, by several orders of magnitude, the values of conventionally determined MICs. High biofilm resistance results in ineffective antifungal therapy of biofilm infections. Therefore, if possible, the colonized implant should be removed. Conservative therapy should involve antifungals with a proven effect on the biofilm (e.g. caspofungin). The most effective measure in fighting biofilm infections is prevention, especially adhering to
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Turbulence accelerates the growth of drinking water biofilms.
Tsagkari, E; Sloan, W T
2018-06-01
Biofilms are found at the inner surfaces of drinking water pipes and, therefore, it is essential to understand biofilm processes to control their formation. Hydrodynamics play a crucial role in shaping biofilms. Thus, knowing how biofilms form, develop and disperse under different flow conditions is critical in the successful management of these systems. Here, the development of biofilms after 4 weeks, the initial formation of biofilms within 10 h and finally, the response of already established biofilms within 24-h intervals in which the flow regime was changed, were studied using a rotating annular reactor under three different flow regimes: turbulent, transition and laminar. Using fluorescence microscopy, information about the number of microcolonies on the reactor slides, the surface area of biofilms and of extracellular polymeric substances and the biofilm structures was acquired. Gravimetric measurements were conducted to characterise the thickness and density of biofilms, and spatial statistics were used to characterise the heterogeneity and spatial correlation of biofilm structures. Contrary to the prevailing view, it was shown that turbulent flow did not correlate with a reduction in biofilms; turbulence was found to enhance both the initial formation and the development of biofilms on the accessible surfaces. Additionally, after 24-h changes of the flow regime it was indicated that biofilms responded to the quick changes of the flow regime. Overall, this work suggests that different flow conditions can cause substantial changes in biofilm morphology and growth and specifically that turbulent flow can accelerate biofilm growth in drinking water.
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Carbohydrate Coating Reduces Adhesion of Biofilm-Forming Bacillus subtilis to Gold Surfaces
Kesel, S.; Mader, A.; Seeberger, P. H.; Lieleg, O.
2014-01-01
The growth of bacterial biofilms in pipes and food tanks causes severe problems in industry. Biofilms growing on medical implants or catheters are of great concern, as they can cause serious infections and decrease the functionality of the medical device. The prevention of bacterial adhesion—the first step in colonization and biofilm formation—is therefore very important. Current research comprises alterations in surface properties, the prevention of adhesin biosynthesis, inhibition with receptor analogs, or the development of anti-adhesive vaccines. We present a new approach that allows us to study bacterial adhesion with high sensitivity in real-time while testing several different surfaces in parallel. Using the cantilever-array technique we demonstrate that coating of gold surfaces with mono- or disaccharides results in a reduction of the bacterial adhesion of the biofilm-forming bacterium Bacillus subtilis NCIB 3610 to these gold surfaces. This reduction in bacterial adhesion is independent of the studied carbohydrate. Using several mutant strains, we investigate the underlying molecular interactions, and our results suggest that adhesion to gold surfaces is mediated by thiol groups present in proteins of the bacterial cell membrane or biofilm matrix proteins expressed at low levels by the wild-type strain. Furthermore, our data indicate that the adhesion of B. subtilis NCIB 3610 to carbohydrate-coated gold surfaces is facilitated by interactions between carbohydrates installed on the cantilever gold surface and an exopolysaccharide expressed by this strain. Understanding general and specific contributions of molecular interactions mediating bacterial adhesion will enable its prevention in the future. PMID:25038098
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Bacterial Biofilms in Jones Tubes.
Ahn, Eric S; Hauck, Matthew J; Kirk Harris, Jonathan; Robertson, Charles E; Dailey, Roger A
To investigate the presence and microbiology of bacterial biofilms on Jones tubes (JTs) by direct visualization with scanning electron microscopy and polymerase chain reaction (PCR) of representative JTs, and to correlate these findings with inflammation and/or infection related to the JT. In this study, prospective case series were performed. JTs were recovered from consecutive patients presenting to clinic for routine cleaning or recurrent irritation/infection. Four tubes were processed for scanning electron microscopy alone to visualize evidence of biofilms. Two tubes underwent PCR alone for bacterial quantification. One tube was divided in half and sent for scanning electron microscopy and PCR. Symptoms related to the JTs were recorded at the time of recovery. Seven tubes were obtained. Five underwent SEM, and 3 out of 5 showed evidence of biofilms (60%). Two of the 3 biofilms demonstrated cocci and the third revealed rods. Three tubes underwent PCR. The predominant bacteria identified were Pseudomonadales (39%), Pseudomonas (16%), and Staphylococcus (14%). Three of the 7 patients (43%) reported irritation and discharge at presentation. Two symptomatic patients, whose tubes were imaged only, revealed biofilms. The third symptomatic patient's tube underwent PCR only, showing predominantly Staphylococcus (56%) and Haemophilus (36%) species. Two of the 4 asymptomatic patients also showed biofilms. All symptomatic patients improved rapidly after tube exchange and steroid antibiotic drops. Bacterial biofilms were variably present on JTs, and did not always correlate with patients' symptoms. Nevertheless, routine JT cleaning is recommended to treat and possibly prevent inflammation caused by biofilms.
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Prevention and treatment of Staphylococcus aureus biofilms
Bhattacharya, Mohini; Wozniak, Daniel J; Stoodley, Paul; Hall-Stoodley, Luanne
2016-01-01
S. aureus colonizes both artificial and tissue surfaces in humans causing chronic persistent infections that are difficult to cure. It is a notorious pathogen due to its antibiotic recalcitrance and phenotypic adaptability, both of which are facilitated by its ability to develop biofilms. S. aureus biofilms challenge conventional anti-infective approaches, most notably antibiotic therapy. Therefore there is an unmet need to develop and include parallel approaches that target S. aureus biofilm infections. This review discusses two broad anti-infective strategies: (1) preventative approaches (anti-biofilm surface coatings, the inclusion of biofilm-specific vaccine antigens); and (2) approaches aimed at eradicating established S. aureus biofilms, particularly those associated with implant infections. Advances in understanding the distinct nature of S. aureus biofilm development and pathogenesis have led to growing optimism in S. aureus biofilm targeted anti-infective strategies. Further research is needed however, to see the successful administration and validation of these approaches to the diverse types of infections caused by S. aureus biofilms from multiple clinical strains. PMID:26646248
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Schlafer, Sebastian; Ibsen, Casper J S; Birkedal, Henrik; Nyvad, Bente
2017-01-01
This 2-period crossover study investigated the effect of calcium-phosphate-osteopontin particles on biofilm formation and pH in 48-h biofilms grown in situ. Bovine milk osteopontin is a highly phosphorylated glycoprotein that has been shown to interfere with bacterial adhesion to salivary-coated surfaces. Calcium-phosphate-osteopontin particles have been shown to reduce biofilm formation and pH drops in a 5-species laboratory model of dental biofilm without affecting bacterial viability. Here, smooth surface biofilms from 10 individuals were treated ex vivo 6 times/day for 30 min with either calcium-phosphate-osteopontin particles or sterile saline. After growth, the amount of biofilm formed was determined by confocal microscopy, and pH drops upon exposure to glucose were monitored using confocal-microscopy-based pH ratiometry. A total of 160 biofilms were analysed. No adverse effects of repeated ex vivo treatment with calcium-phosphate-osteopontin particles were observed. Particle treatment resulted in a 32% lower amount of biofilm formed (p < 0.05), but large inter-individual differences could be observed. Biofilm pH was significantly higher upon particle treatment, both shortly after the addition of glucose and after 30 min of incubation with glucose (p < 0.05). Calcium-phosphate-osteopontin particles may represent a new therapeutic approach to caries control and aim at directly targeting virulence factors involved in the caries process. Further studies are required to determine the effect of particle treatment on more acidogenic/aciduric biofilms as well as the remineralizing potential of the particles. © 2016 S. Karger AG, Basel.
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Biofilms and Antifungal Susceptibility Testing.
Simitsopoulou, Maria; Chatzimoschou, Athanasios; Roilides, Emmanuel
2016-01-01
Yeasts and filamentous fungi both exist as single cells and hyphal forms, two morphologies used by most fungal organisms to create a complex multilayered biofilm structure. In this chapter we describe the most widely used assays for the determination of biofilm production and assessment of susceptibility of biofilms to antifungal agents or host phagocytes as various methods, the most frequent of which are staining, confocal laser scanning microscopy, quantification of extracellular DNA and protein associated with extracellular matrix and XTT metabolic reduction assay. Pathway-focused biofilm gene expression profiling is assessed by real-time reverse transcriptase polymerase chain reaction.
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Liu, Sze-Wei; Myroforidis, Helen; Zalizniak, Ilya; Palamara, Joseph E. A.; Huq, N. Laila; Reynolds, Eric C.
2016-01-01
Glass ionomer cements (GIC) are dental restorative materials that are suitable for modification to help prevent dental plaque (biofilm) formation. The aim of this study was to determine the effects of incorporating casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) into a GIC on the colonisation and establishment of Streptococcus mutans biofilms and the effects of aqueous CPP-ACP on established S mutans biofilms. S. mutans biofilms were either established in flow cells before a single ten min exposure to 1% w/v CPP-ACP treatment or cultured in static wells or flow cells with either GIC or GIC containing 3% w/w CPP-ACP as the substratum. The biofilms were then visualised using confocal laser scanning microscopy after BacLight LIVE/DEAD staining. A significant decrease in biovolume and average thickness of S. mutans biofilms was observed in both static and flow cell assays when 3% CPP-ACP was incorporated into the GIC substratum. A single ten min treatment with aqueous 1% CPP-ACP resulted in a 58% decrease in biofilm biomass and thickness of established S. mutans biofilms grown in a flow cell. The treatment also significantly altered the structure of these biofilms compared with controls. The incorporation of 3% CPP-ACP into GIC significantly reduced S. mutans biofilm development indicating another potential anticariogenic mechanism of this material. Additionally aqueous CPP-ACP disrupted established S. mutans biofilms. The use of CPP-ACP containing GIC combined with regular CPP-ACP treatment may lower S. mutans challenge. PMID:27589264
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Mudrak, Benjamin; Tamayo, Rita
2012-05-01
Vibrio cholerae is the causative agent of the deadly diarrheal disease cholera. As part of its life cycle, V. cholerae persists in marine environments, where it forms surface-attached communities commonly described as biofilms. Evidence indicates that these biofilms constitute the infectious form of the pathogen during outbreaks. Previous work has shown that biofilm-derived V. cholerae cells, even when fully dispersed from the biofilm matrix, are vastly more infectious than planktonic (free-living) cells. Here, we sought to identify factors that contribute to biofilm-induced hyperinfectivity in V. cholerae, and we present evidence for one aspect of the molecular basis of this phenotype. We identified proteins upregulated during growth in biofilms and determined their contributions to the hyperinfectivity phenotype. We found that PstS2, the periplasmic component of the Pst2 phosphate uptake system, was enriched in biofilms. Another gene in the pst2 locus was transcriptionally upregulated in biofilms. Using the infant mouse model, we found that mutation of two pst2 components resulted in impaired colonization. Importantly, deletion of the Pst2 inner membrane complex caused a greater colonization defect after growth in a biofilm compared to shaking culture. Based on these data, we propose that V. cholerae cells in biofilms upregulate the Pst2 system and therefore gain an advantage upon entry into the host. Further characterization of factors contributing to biofilm-induced hyperinfectivity in V. cholerae will improve our understanding of the transmission of the bacteria from natural aquatic habitats to the human host.
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Malone, Matthew; Goeres, Darla M; Gosbell, Iain; Vickery, Karen; Jensen, Slade; Stoodley, Paul
2017-02-01
The concept of biofilms in human health and disease is now widely accepted as cause of chronic infection. Typically, biofilms show remarkable tolerance to many forms of treatments and the host immune response. This has led to vast increase in research to identify new (and sometimes old) anti-biofilm strategies that demonstrate effectiveness against these tolerant phenotypes. Areas covered: Unfortunately, a standardized methodological approach of biofilm models has not been adopted leading to a large disparity between testing conditions. This has made it almost impossible to compare data across multiple laboratories, leaving large gaps in the evidence. Furthermore, many biofilm models testing anti-biofilm strategies aimed at the medical arena have not considered the matter of relevance to an intended application. This may explain why some in vitro models based on methodological designs that do not consider relevance to an intended application fail when applied in vivo at the clinical level. Expert commentary: This review will explore the issues that need to be considered in developing performance standards for anti-biofilm therapeutics and provide a rationale for the need to standardize models/methods that are clinically relevant. We also provide some rational as to why no standards currently exist.
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Effects of probiotic fermented milk on biofilms, oral microbiota, and enamel.
Lodi, Carolina Simonetti; Oliveira, Lidiane Viana; Brighenti, Fernanda Lourenção; Delbem, Alberto Carlos Botazzo; Martinhon, Cleide Cristina Rodrigues
2015-01-01
The aim of this study was to evaluate in vitro and in vivo the effects of 2 brands of probiotic fermented milk on biofilms, oral microbiota, and enamel. For the in situ experiment, ten volunteers wore palatine devices containing four blocks of bovine dental enamel over 3 phases, during which 20% sucrose solution, Yakult® (Treatment A), and Batavito® (Treatment B) were dropped on the enamel blocks. Salivary microbial counts were obtained and biofilm samples were analyzed after each phase. For the in vivo experiment, the same ten volunteers drunk Yakult® (Treatment C) and Batavito® (Treatment D) in two phases. Saliva samples were collected for microbial analysis after each phase. The in situ study showed that in comparison with Treatment A, Treatment B resulted in fewer total cultivable anaerobes and facultative microorganisms in biofilms, higher final microhardness, lower percentage change in surface hardness, and smaller integrated subsurface enamel hardness. In the in vivo study, Treatment D resulted in a reduction in the counts of all microorganisms. The results suggested that the probiotic fermented milk Batavito®, but not Yakult®, reduced the amount of oral microorganisms and mineral loss in bovine enamel.
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Focus on the physics of biofilms
NASA Astrophysics Data System (ADS)
Lecuyer, Sigolene; Stocker, Roman; Rusconi, Roberto
2015-03-01
Bacteria are the smallest and most abundant form of life. They have traditionally been considered as primarily planktonic organisms, swimming or floating in a liquid medium, and this view has shaped many of the approaches to microbial processes, including for example the design of most antibiotics. However, over the last few decades it has become clear that many bacteria often adopt a sessile, surface-associated lifestyle, forming complex multicellular communities called biofilms. Bacterial biofilms are found in a vast range of environments and have major consequences on human health and industrial processes, from biofouling of surfaces to the spread of diseases. Although the study of biofilms has been biologists’ territory for a long time, a multitude of phenomena in the formation and development of biofilms hinges on physical processes. We are pleased to present a collection of research papers that discuss some of the latest developments in many of the areas to which physicists can contribute a deeper understanding of biofilms, both experimentally and theoretically. The topics covered range from the influence of physical environmental parameters on cell attachment and subsequent biofilm growth, to the use of local probes and imaging techniques to investigate biofilm structure, to the development of biofilms in complex environments and the modeling of colony morphogenesis. The results presented contribute to addressing some of the major challenges in microbiology today, including the prevention of surface contamination, the optimization of biofilm disruption methods and the effectiveness of antibiotic treatments.
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Biofilm formation by pathogenic Prototheca algae.
Kwiecinski, J
2015-12-01
Prototheca microalgae are the only plants known to cause infections in humans and animals. The mechanisms of Prototheca infections are poorly understood, and no good treatments are available. Biofilms-surface-attached, three-dimensional microbial communities contributing to chronic infections-are formed by many pathogenic bacteria and fungi, but it is not known if Prototheca algae also have this ability. This study shows that various Prototheca species form biofilms composed of surface-attached cells in all growth phases, linked together by matrix containing DNA and polysaccharides. Biofilm formation was modulated by the presence of host plasma or milk. Compared to planktonic cells, Prototheca biofilms caused decreased release of IL-6 by mononuclear immune cells and responded differently to treatment with antimicrobials. Prototheca biofilms possibly contribute to chronic and hard-to-treat character of those algal infections. Prototheca algae are the only existing pathogenic plants. Almost nothing is known about mechanisms of Prototheca infections. This study identifies that, similar to pathogenic bacteria and fungi, Prototheca algae can form biofilms. These biofilms induce reduced immune cell activation relative to planktonic cells, and are also less susceptible to antimicrobials. Biofilm formation by Prototheca could be the first in vitro correlate of pathogenicity, opening a new research field for this pathogen. © 2015 The Society for Applied Microbiology.
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Effect of anti-biofilm glass-ionomer cement on Streptococcus mutans biofilms.
Wang, Su-Ping; Ge, Yang; Zhou, Xue-Dong; Xu, Hockin Hk; Weir, Michael D; Zhang, Ke-Ke; Wang, Hao-Hao; Hannig, Matthias; Rupf, Stefan; Li, Qian; Cheng, Lei
2016-06-30
Dental restorative materials with antimicrobial properties can inhibit bacterial colonization, which may result in a reduction of caries at tooth-filling interaction zones. This study aimed to develop antibacterial glass-ionomer cements (GIC) containing a quaternary ammonium monomer (dimethylaminododecyl methacrylate, DMADDM), and to investigate their effect on material performance and antibacterial properties. Different mass fractions (0, 1.1% and 2.2%) of DMADDM were incorporated into the GIC. The flexure strength, surface charge density, surface roughness and fluoride release were tested. A Streptococcus mutans biofilm model was used. Exopolysaccharides (EPS) staining was used to analyze the inhibitory effect of DMADDM on the biofilm matrix. In addition, biofilm metabolic activity, lactic acid metabolism and the expression of glucosyltransferase genes gtfB, gtfC and gtfD were measured. GIC containing 1.1% and 2.2% DMADDM had flexural strengths matching those of the commercial control (P>0.1). DMADDM was able to increase the surface charge density but reduced surface roughness (P<0.05). The incorporation of 1.1% and 2.2% DMADDM elevated the release of fluoride by the GIC in the first 2 days (P<0.05). The novel DMADDM-modified GIC significantly reduced biofilm metabolic activity (P<0.05) and decreased lactic acid production (P<0.05). The quantitative polymerase chain reaction (qPCR) results showed that the expression of gtfB, gtfC and gtfD decreased when mass fractions of DMADDM increased (P<0.05). EPS staining showed that both the bacteria and EPS in biofilm decreased in the DMADDM groups. The incorporation of DMADDM could modify the properties of GIC to influence the development of S. mutans biofilms. In this study, we investigated the interface properties of antibacterial materials for the first time. GIC containing DMADDM can improve material performance and antibacterial properties and may contribute to the better management of secondary caries.
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Garrison, Aaron T; Abouelhassan, Yasmeen; Kallifidas, Dimitris; Bai, Fang; Ukhanova, Maria; Mai, Volker; Jin, Shouguang; Luesch, Hendrik; Huigens, Robert W
2015-12-01
Conventional antibiotics are ineffective against non-replicating bacteria (for example, bacteria within biofilms). We report a series of halogenated phenazines (HP), inspired by marine antibiotic 1, that targets persistent bacteria. HP 14 demonstrated the most potent biofilm eradication activities to date against MRSA, MRSE, and VRE biofilms (MBEC = 0.2-12.5 μM), as well as the effective killing of MRSA persister cells in non-biofilm cultures. Frontline MRSA treatments, vancomycin and daptomycin, were unable to eradicate MRSA biofilms or non-biofilm persisters alongside 14. HP 13 displayed potent antibacterial activity against slow-growing M. tuberculosis (MIC = 3.13 μM), the leading cause of death by bacterial infection around the world. HP analogues effectively target persistent bacteria through a mechanism that is non-toxic to mammalian cells and could have a significant impact on treatments for chronic bacterial infections. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Belfield, Katherine; Bayston, Roger; Hajduk, Nadzieja; Levell, Georgia; Birchall, John P; Daniel, Matija
2017-09-01
To evaluate potential anti-biofilm agents for their ability to enhance the activity of antibiotics for local treatment of localized biofilm infections. Staphylococcus aureus and Pseudomonas aeruginosa in vitro biofilm models were developed. The putative antibiotic enhancers N-acetylcysteine, acetylsalicylic acid, sodium salicylate, recombinant human deoxyribonuclease I, dispersin B, hydrogen peroxide and Johnson's Baby Shampoo (JBS) were tested for their anti-biofilm activity alone and their ability to enhance the activity of antibiotics for 7 or 14 days, against 5 day old biofilms. The antibiotic enhancers were paired with rifampicin and clindamycin against S. aureus and gentamicin and ciprofloxacin against P. aeruginosa. Isolates from biofilms that were not eradicated were tested for antibiotic resistance. Antibiotic levels 10× MIC and 100× MIC significantly reduced biofilm, but did not consistently eradicate it. Antibiotics at 100× MIC with 10% JBS for 14 days was the only treatment to eradicate both staphylococcal and pseudomonal biofilms. Recombinant human deoxyribonuclease I significantly reduced staphylococcal biofilm. Emergence of resistance of surviving isolates was minimal and was often associated with the small colony variant phenotype. JBS enhanced the activity of antibiotics and several other promising anti-biofilm agents were identified. Antibiotics with 10% JBS eradicated biofilms produced by both organisms. Such combinations might be useful in local treatment of localized biofilm infections. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Killing of Serratia marcescens biofilms with chloramphenicol.
Ray, Christopher; Shenoy, Anukul T; Orihuela, Carlos J; González-Juarbe, Norberto
2017-03-29
Serratia marcescens is a Gram-negative bacterium with proven resistance to multiple antibiotics and causative of catheter-associated infections. Bacterial colonization of catheters mainly involves the formation of biofilm. The objectives of this study were to explore the susceptibility of S. marcescens biofilms to high doses of common antibiotics and non-antimicrobial agents. Biofilms formed by a clinical isolate of S. marcescens were treated with ceftriaxone, kanamycin, gentamicin, and chloramphenicol at doses corresponding to 10, 100 and 1000 times their planktonic minimum inhibitory concentration. In addition, biofilms were also treated with chemical compounds such as polysorbate-80 and ursolic acid. S. marcescens demonstrated susceptibility to ceftriaxone, kanamycin, gentamicin, and chloramphenicol in its planktonic form, however, only chloramphenicol reduced both biofilm biomass and biofilm viability. Polysorbate-80 and ursolic acid had minimal to no effect on either planktonic and biofilm grown S. marcescens. Our results suggest that supratherapeutic doses of chloramphenicol can be used effectively against established S. marcescens biofilms.
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Single-species microbial biofilm screening for industrial applications.
Li, Xuan Zhong; Hauer, Bernhard; Rosche, Bettina
2007-10-01
While natural microbial biofilms often consist of multiple species, single-species biofilms are of great interest to biotechnology. The current study evaluates biofilm formation for common industrial and laboratory microorganisms. A total of 68 species of biosafety level one bacteria and yeasts from over 40 different genera and five phyla were screened by growing them in microtiter plates and estimating attached biomass by crystal violet staining. Most organisms showed biofilm formation on surfaces of polystyrene within 24 h. By changing a few simple conditions such as substratum characteristics, inoculum and nutrient availability, 66 strains (97%) demonstrated biofilm formation under at least one of the experimental conditions and over half of these strains were classified as strong biofilm formers, potentially suitable as catalysts in biofilm applications. Many non-motile bacteria were also strong biofilm formers. Biofilm morphologies were visualized for selected strains. A model organism, Zymomonas mobilis, easily established itself as a biofilm on various reactor packing materials, including stainless steel.
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Current Research Approaches to Target Biofilm Infections
van Tilburg Bernardes, Erik; Lewenza, Shawn
2017-01-01
This review will focus on strategies to develop new treatments that target the biofilm mode of growth and that can be used to treat biofilm infections. These approaches aim to reduce or inhibit biofilm formation, or to increase biofilm dispersion. Many antibiofilm compounds are not bactericidal but render the cells in a planktonic growth state, which are more susceptible to antibiotics and more easily cleared by the immune system. Novel compounds are being developed with antibiofilm activity that includes antimicrobial peptides, natural products, small molecules and polymers. Bacteriophages are being considered for use in treating biofilms, as well as the use of enzymes that degrade the extracellular matrix polymers to dissolve biofilms. There is great potential in these new approaches for use in treating chronic biofilm infections. PMID:28748199
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Lourenço, António; de Las Heras, Aitor; Scortti, Mariela; Vazquez-Boland, Jose; Frank, Joseph F; Brito, Luisa
2013-10-01
The food-borne pathogen Listeria monocytogenes is the causative agent of the severe human and animal disease listeriosis. The persistence of this bacterium in food processing environments is mainly attributed to its ability to form biofilms. The search for proteins associated with biofilm formation is an issue of great interest, with most studies targeting the whole bacterial proteome. Nevertheless, exoproteins constitute an important class of molecules participating in various physiological processes, such as cell signaling, pathogenesis, and matrix remodeling. The aim of this work was to quantify differences in protein abundance between exoproteomes from a biofilm and from the planktonic state. For this, two field strains previously evaluated to be good biofilm producers (3119 and J311) were used, and a procedure for the recovery of biofilm exoproteins was optimized. Proteins were resolved by two-dimensional difference gel electrophoresis and identified by electrospray ionization-tandem mass spectrometry. One of the proteins identified in higher abundance in the biofilm exoproteomes of both strains was the putative cell wall binding protein Lmo2504. A mutant strain with deletion of the gene for Lmo2504 was produced (3119Δlmo2504), and its biofilm-forming ability was compared to that of the wild type using the crystal violet and the ruthenium red assays as well as scanning electron microscopy. The results confirmed the involvement of Lmo2504 in biofilm formation, as strain 3119Δlmo2504 showed a significantly (P < 0.05) lower biofilm-forming ability than the wild type. The identification of additional exoproteins associated with biofilm formation may lead to new strategies for controlling this pathogen in food processing facilities.
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Barros, Joana; Grenho, Liliana; Fontenente, Sílvia; Manuel, Cândida M; Nunes, Olga C; Melo, Luís F; Monteiro, Fernando J; Ferraz, Maria P
2017-02-01
Implant-associated infections are caused by surface-adhering microorganisms persisting as biofilms, resistant to host defense and antimicrobial agents. Given the limited efficacy of traditional antibiotics, novel strategies may rely on the prevention of such infections through the design of new biomaterials. In this work, two antimicrobial agents applied to nanohydroxyapatite materials-namely, chlorhexidine digluconate (CHX) and zinc oxide (ZnO) nanoparticles-were compared concerning their ability to avoid single- or dual-species biofilms of Staphylococcus aureus and Escherichia coli. The resulting biofilms were quantified by the enumeration of colony-forming units and examined by confocal microscopy using both Live/Dead staining and bacterial-specific fluorescent in situ hybridization. The sessile population arrangement was also observed by scanning electron microscopy. Both biomaterials showed to be effective in impairing bacterial adhesion and proliferation for either single- or dual-species biofilms. Furthermore, a competitive interaction was observed for dual-species biofilms wherein E. coli exhibited higher proliferative capacity than S. aureus, an inverse behavior from the one observed in single-species biofilms. Therefore, either nanoHA-CHX or nanoHA-ZnO surfaces appear as promising alternatives to antibiotics for the prevention of devices-related infections avoiding the critical risk of antibiotic-resistant strains emergence. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 491-497, 2017. © 2016 Wiley Periodicals, Inc.
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Material modeling of biofilm mechanical properties.
Laspidou, C S; Spyrou, L A; Aravas, N; Rittmann, B E
2014-05-01
A biofilm material model and a procedure for numerical integration are developed in this article. They enable calculation of a composite Young's modulus that varies in the biofilm and evolves with deformation. The biofilm-material model makes it possible to introduce a modeling example, produced by the Unified Multi-Component Cellular Automaton model, into the general-purpose finite-element code ABAQUS. Compressive, tensile, and shear loads are imposed, and the way the biofilm mechanical properties evolve is assessed. Results show that the local values of Young's modulus increase under compressive loading, since compression results in the voids "closing," thus making the material stiffer. For the opposite reason, biofilm stiffness decreases when tensile loads are imposed. Furthermore, the biofilm is more compliant in shear than in compression or tension due to the how the elastic shear modulus relates to Young's modulus. Copyright © 2014 Elsevier Inc. All rights reserved.
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Biofilm inhibitors that target amyloid proteins.
Romero, Diego; Sanabria-Valentín, Edgardo; Vlamakis, Hera; Kolter, Roberto
2013-01-24
Bacteria establish stable communities, known as biofilms, that are resistant to antimicrobials. Biofilm robustness is due to the presence of an extracellular matrix, which for several species-among them Bacillus subtilis-includes amyloid-like protein fibers. In this work, we show that B. subtilis biofilms can be a simple and reliable tool for screening of molecules with antiamyloid activity. We identified two molecules, AA-861 and parthenolide, which efficiently inhibited biofilms by preventing the formation of amyloid-like fibers. Parthenolide also disrupted pre-established biofilms. These molecules also impeded the formation of biofilms of other bacterial species that secrete amyloid proteins, such as Bacillus cereus and Escherichia coli. Furthermore, the identified molecules decreased the conversion of the yeast protein New1 to the prion state in a heterologous host, indicating the broad range of activity of the molecules. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Pseudomonas aeruginosa Biofilm, a Programmed Bacterial Life for Fitness.
Lee, Keehoon; Yoon, Sang Sun
2017-06-28
A biofilm is a community of microbes that typically inhabit on surfaces and are encased in an extracellular matrix. Biofilms display very dissimilar characteristics to their planktonic counterparts. Biofilms are ubiquitous in the environment and influence our lives tremendously in both positive and negative ways. Pseudomonas aeruginosa is a bacterium known to produce robust biofilms. P. aeruginosa biofilms cause severe problems in immunocompromised patients, including those with cystic fibrosis or wound infection. Moreover, the unique biofilm properties further complicate the eradication of the biofilm infection, leading to the development of chronic infections. In this review, we discuss the history of biofilm research and general characteristics of bacterial biofilms. Then, distinct features pertaining to each stage of P. aeruginosa biofilm development are highlighted. Furthermore, infections caused by biofilms on their own or in association with other bacterial species ( i.e. , multispecies biofilms) are discussed in detail.
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INVESTIGATIONS INTO BIOFOULING PHENOMENA IN FINE PORE AERATION DEVICES
Microbiologically-based procedures were used to describe biofouling phenomena on fine pore aeration devices and to determine whether biofilm characteristics could be related to diffuser process performance parameters. Fine pore diffusers were obtained from five municipal wastewa...
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Beaudoin, Trevor; Zhang, Li; Hinz, Aaron J; Parr, Christopher J; Mah, Thien-Fah
2012-06-01
Bacteria growing in biofilms are responsible for a large number of persistent infections and are often more resistant to antibiotics than are free-floating bacteria. In a previous study, we identified a Pseudomonas aeruginosa gene, ndvB, which is important for the formation of periplasmic glucans. We established that these glucans function in biofilm-specific antibiotic resistance by sequestering antibiotic molecules away from their cellular targets. In this study, we investigate another function of ndvB in biofilm-specific antibiotic resistance. DNA microarray analysis identified 24 genes that were responsive to the presence of ndvB. A subset of 20 genes, including 8 ethanol oxidation genes (ercS', erbR, exaA, exaB, eraR, pqqB, pqqC, and pqqE), was highly expressed in wild-type biofilm cells but not in ΔndvB biofilms, while 4 genes displayed the reciprocal expression pattern. Using quantitative real-time PCR, we confirmed the ndvB-dependent expression of the ethanol oxidation genes and additionally demonstrated that these genes were more highly expressed in biofilms than in planktonic cultures. Expression of erbR in ΔndvB biofilms was restored after the treatment of the biofilm with periplasmic extracts derived from wild-type biofilm cells. Inactivation of ethanol oxidation genes increased the sensitivity of biofilms to tobramycin. Together, these results reveal that ndvB affects the expression of multiple genes in biofilms and that ethanol oxidation genes are linked to biofilm-specific antibiotic resistance.
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Transferrin Impacts Bacillus thuringiensis Biofilm Levels
Brown, Elrica; Taplin, Martha; Garcia, Angel; Williams-Mapp, Baracka
2016-01-01
The present study examined the impact of transferrin on Bacillus thuringiensis biofilms. Three commercial strains, an environmental strain (33679), the type strain (10792), and an isolate from a diseased insect (700872), were cultured in iron restricted minimal medium. All strains produced biofilm when grown in vinyl plates at 30°C. B. thuringiensis 33679 had a biofilm biomass more than twice the concentration exhibited by the other strains. The addition of transferrin resulted in slightly increased growth yields for 2 of the 3 strains tested, including 33679. In contrast, the addition of 50 μg/mL of transferrin resulted in an 80% decrease in biofilm levels for strain 33679. When the growth temperature was increased to 37°C, the addition of 50 μg/mL of transferrin increased culture turbidity for only strain 33679. Biofilm levels were again decreased in strain 33679 at 37°C. Growth of B. thuringiensis cultures in polystyrene resulted in a decrease in overall growth yields at 30°C, with biofilm levels significantly decreased for 33679 in the presence of transferrin. These findings demonstrate that transferrin impacts biofilm formation in select strains of B. thuringiensis. Identification of these differences in biofilm regulation may be beneficial in elucidating potential virulence mechanisms among the differing strains. PMID:28025643
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Susceptibility of Staphylococcus aureus biofilms to reactive discharge gases.
Traba, Christian; Liang, Jun F
2011-08-01
Formation of bacterial biofilms at solid-liquid interfaces creates numerous problems in both industrial and biomedical sciences. In this study, the susceptibility of Staphylococcus aureus biofilms to discharge gas generated from plasma was tested. It was found that despite distinct chemical/physical properties, discharge gases from oxygen, nitrogen, and argon demonstrated very potent and almost the same anti-biofilm activity. The bacterial cells in S. aureus biofilms were killed (>99.9%) by discharge gas within minutes of exposure. Under optimal experimental conditions, no bacteria and biofilm re-growth from discharge gas treated biofilms was found. Further studies revealed that the anti-biofilm activity of the discharge gas occurred by two distinct mechanisms: (1) killing bacteria in biofilms by causing severe cell membrane damage, and (2) damaging the extracellular polymeric matrix in the architecture of the biofilm to release biofilm from the surface of the solid substratum. Information gathered from this study provides an insight into the anti-biofilm mechanisms of plasma and confirms the applications of discharge gas in the treatment of biofilms and biofilm related bacterial infections.
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The Interface between Fungal Biofilms and Innate Immunity.
Kernien, John F; Snarr, Brendan D; Sheppard, Donald C; Nett, Jeniel E
2017-01-01
Fungal biofilms are communities of adherent cells surrounded by an extracellular matrix. These biofilms are commonly found during infection caused by a variety of fungal pathogens. Clinically, biofilm infections can be extremely difficult to eradicate due to their resistance to antifungals and host defenses. Biofilm formation can protect fungal pathogens from many aspects of the innate immune system, including killing by neutrophils and monocytes. Altered immune recognition during this phase of growth is also evident by changes in the cytokine profiles of monocytes and macrophages exposed to biofilm. In this manuscript, we review the host response to fungal biofilms, focusing on how these structures are recognized by the innate immune system. Biofilms formed by Candida, Aspergillus , and Cryptococcus have received the most attention and are highlighted. We describe common themes involved in the resilience of fungal biofilms to host immunity and give examples of biofilm defenses that are pathogen-specific.
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Red and Green Fluorescence from Oral Biofilms
Hoogenkamp, Michel A.; Krom, Bastiaan P.; Janus, Marleen M.; ten Cate, Jacob M.; de Soet, Johannes J.; Crielaard, Wim; van der Veen, Monique H.
2016-01-01
Red and green autofluorescence have been observed from dental plaque after excitation by blue light. It has been suggested that this red fluorescence is related to caries and the cariogenic potential of dental plaque. Recently, it was suggested that red fluorescence may be related to gingivitis. Little is known about green fluorescence from biofilms. Therefore, we assessed the dynamics of red and green fluorescence in real-time during biofilm formation. In addition, the fluorescence patterns of biofilm formed from saliva of eight different donors are described under simulated gingivitis and caries conditions. Biofilm formation was analysed for 12 hours under flow conditions in a microfluidic BioFlux flow system with high performance microscopy using a camera to allow live cell imaging. For fluorescence images dedicated excitation and emission filters were used. Both green and red fluorescence were linearly related with the total biomass of the biofilms. All biofilms displayed to some extent green and red fluorescence, with higher red and green fluorescence intensities from biofilms grown in the presence of serum (gingivitis simulation) as compared to the sucrose grown biofilms (cariogenic simulation). Remarkably, cocci with long chain lengths, presumably streptococci, were observed in the biofilms. Green and red fluorescence were not found homogeneously distributed within the biofilms: highly fluorescent spots (both green and red) were visible throughout the biomass. An increase in red fluorescence from the in vitro biofilms appeared to be related to the clinical inflammatory response of the respective saliva donors, which was previously assessed during an in vivo period of performing no-oral hygiene. The BioFlux model proved to be a reliable model to assess biofilm fluorescence. With this model, a prediction can be made whether a patient will be prone to the development of gingivitis or caries. PMID:27997567
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Red and Green Fluorescence from Oral Biofilms.
Volgenant, Catherine M C; Hoogenkamp, Michel A; Krom, Bastiaan P; Janus, Marleen M; Ten Cate, Jacob M; de Soet, Johannes J; Crielaard, Wim; van der Veen, Monique H
2016-01-01
Red and green autofluorescence have been observed from dental plaque after excitation by blue light. It has been suggested that this red fluorescence is related to caries and the cariogenic potential of dental plaque. Recently, it was suggested that red fluorescence may be related to gingivitis. Little is known about green fluorescence from biofilms. Therefore, we assessed the dynamics of red and green fluorescence in real-time during biofilm formation. In addition, the fluorescence patterns of biofilm formed from saliva of eight different donors are described under simulated gingivitis and caries conditions. Biofilm formation was analysed for 12 hours under flow conditions in a microfluidic BioFlux flow system with high performance microscopy using a camera to allow live cell imaging. For fluorescence images dedicated excitation and emission filters were used. Both green and red fluorescence were linearly related with the total biomass of the biofilms. All biofilms displayed to some extent green and red fluorescence, with higher red and green fluorescence intensities from biofilms grown in the presence of serum (gingivitis simulation) as compared to the sucrose grown biofilms (cariogenic simulation). Remarkably, cocci with long chain lengths, presumably streptococci, were observed in the biofilms. Green and red fluorescence were not found homogeneously distributed within the biofilms: highly fluorescent spots (both green and red) were visible throughout the biomass. An increase in red fluorescence from the in vitro biofilms appeared to be related to the clinical inflammatory response of the respective saliva donors, which was previously assessed during an in vivo period of performing no-oral hygiene. The BioFlux model proved to be a reliable model to assess biofilm fluorescence. With this model, a prediction can be made whether a patient will be prone to the development of gingivitis or caries.
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Biofilms in periprosthetic orthopedic infections
McConoughey, Stephen J; Howlin, Rob; Granger, Jeff F; Manring, Maurice M; Calhoun, Jason H; Shirtlif, Mark; Kathju, Sandeep; Stoodley, Paul
2015-01-01
As the number of total joint arthroplasty and internal fixation procedures continues to rise, the threat of infection following surgery has significant clinical implications. These infections may have highly morbid consequences to patients, who often endure additional surgeries and lengthy exposures to systemic antibiotics, neither of which are guaranteed to resolve the infection. Of particular concern is the threat of bacterial biofilm development, since biofilm-mediated infections are difficult to diagnose and effective treatments are lacking. Developing therapeutic strategies have targeted mechanisms of biofilm formation and the means by which these bacteria communicate with each other to take on specialized roles such as persister cells within the biofilm. In addition, prevention of infection through novel coatings for prostheses and the local delivery of high concentrations of antibiotics by absorbable carriers has shown promise in laboratory and animal studies. Biofilm development, especially in an arthoplasty environment, and future diagnostic and treatment options are discussed. PMID:25302955
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Mena Viveros, Nicolás
2014-01-01
According to the National Institute of Health of the USA, «more than 60% of all microbial infections are caused by biofilms».'This can surprise us, but it is enough to consider that common infections like those of the genito-urinary tract, infections produced by catheters, middle ear infections in children, the formation of dental plaque and gingivitis are caused by biofilms, for this statement to seem more realistic. At present this is one of the subjects of great interest within medicine, particularly in otolaryngology. Bacteria have traditionally been considered to be in a free state without evident organization, partly perhaps by the ease of studying them in this form. Nevertheless, the reality is that, in nature, the great majority of these germs form complex colonies adhered to surfaces, colonies that have received the name of biofilms. These biofilms are more common than previously thought and almost all of the people have been in contact with them in the form of infections in the teeth or humid, slippery areas. New treatments that can eradicate them are currently being investigated. Copyright © 2012 Elsevier España, S.L. All rights reserved.
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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.
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Mitra, Sayani; Gachhui, Ratan; Mukherjee, Joydeep
2015-01-01
A direct relationship between biofilm formation and melanogenesis in Shewanella colwelliana with increased oyster recruitment is already established. Previously, S. colwelliana was grown in a newly patented biofilm-cultivation device, the conico-cylindrical flask (CCF), offering interchangeable hydrophobic/hydrophilic surfaces. Melanization was enhanced when S. colwelliana was cultivated in a hydrophobic vessel compared with a hydrophilic vessel. In the present study, melanogenesis in the CCF was positively correlated with increased architectural parameters of the biofilm (mean thickness and biovolume obtained by confocal laser scanning microscopy) and melanin gene (melA) expression observed by densitometry. Niche intertidal conditions were mimicked in a process operated in an ultra-low-speed rotating disk bioreactor, which demonstrated enhanced biofilm formation, melanogenesis, exopolysaccharide synthesis and melA gene expression compared with a process where 12-h periodic immersion and emersion was prevented. The wettability properties of the settling plane as well as intermittent wetting and drying, which influenced biofilm formation and melA expression, may affect oyster settlement in nature.
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Inhibitory effect of alpha-mangostin on Candida biofilms.
Kaomongkolgit, Ruchadaporn; Jamdee, Kusuma
2017-04-01
The objective of this study was to determine the inhibitory effect of alpha-mangostin on Candida biofilms. Candida species including Candida albicans, Candida krusei, Candida tropicalis, and Candida glabrata were tested. Candida biofilms were formed in flat-bottomed 96-well microtiter plates. The metabolic activity of cells within biofilms was quantified using the XTT assay. The results demonstrated that alpha-mangostin showed a significant anti-biofilm effect on both developing biofilms and preformed biofilms of Candida species. It may be concluded that alpha-mangostin could be an anti-biofilm agent against Candida species. Further in vivo investigations are needed to uncover the therapeutic values of this medicinal plant.
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Biofilms of vaginal Lactobacillus in vitro test.
Wei, Xiao-Yu; Zhang, Rui; Xiao, Bing-Bing; Liao, Qin-Ping
2017-01-01
This paper focuses on biofilms of Lactobacillus spp. - a type of normal flora isolated from healthy human vaginas of women of childbearing age; thereupon, it broadens the research scope of investigation of vaginal normal flora. The static slide culture method was adopted to foster biofilms, marked by specific fluorescence staining. Laser scanning confocal and scanning electron microscopy were used to observe the microstructure of the biofilms. Photographs taken from the microstructure were analysed to calculate the density of the biofilms. The body of Lactobacillus spp., though red, turned yellow when interacting with the green extracellular polysaccharides. The structure of the biofilm and aquaporin within the biofilm were imaged. Lactobacillus density increases over time. This study provides convincing evidence that Lactobacillus can form biofilms and grow over time in vitro. This finding establishes an important and necessary condition for selecting proper strains for the pharmaceutics of vaginal ecology.
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Chau, N P T; Chung, N H; Jeon, J G
2015-08-01
To determine the relationships between the antibacterial activity of NaOCl and treatment time and biofilm age in early Enterococcus faecalis biofilms using a linear fitting procedure. Enterococcus faecalis biofilms were formed on hydroxyapatite discs. To investigate the relationship between the antibacterial activity of NaOCl and biofilm age, 22-, 46-, 70- and 94-h-old biofilms were exposed to NaOCl (0-3%) for 5 min. To investigate the relationship between the antibacterial activity of NaOCl and treatment time, 70-h-old biofilms were exposed to NaOCl (0-3%) for 1, 3, 5 and 7 min. After treatment, colony-forming units (CFUs) were counted. To determine the relationships between these variables, linear fitting was performed. The change in the minimum biofilm eradication concentration (MBEC) of NaOCl followed a linear pattern of biofilm age (R = 0.941, R(2) = 0.886) or treatment time dependence (R = -0.948, R(2) = 0.898). Below the MBEC, the fitting lines for bacterial CFU count versus NaOCl concentration (R ≤ -0.973, R(2) ≥ 0.948) in the 22-, 46-, 70- and 94-h-old biofilms implied that the antibacterial activity of NaOCl decreased as the biofilm age increased. The fitting lines for bacterial CFU count versus NaOCl concentration (R ≤ -0.970, R(2) ≥ 0.942) in the 1-, 3-, 5- and 7-min treatments implied that the antibacterial activity of NaOCl increased with treatment time. These results suggest that the antibacterial activity of NaOCl against early E. faecalis biofilms in root canals may follow a linear pattern depending on biofilm age or treatment time. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.
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Duong, Hien T T; Jung, Kenward; Kutty, Samuel K; Agustina, Sri; Adnan, Nik Nik M; Basuki, Johan S; Kumar, Naresh; Davis, Thomas P; Barraud, Nicolas; Boyer, Cyrille
2014-07-14
Biofilms are increasingly recognized as playing a major role in human infectious diseases, as they can form on both living tissues and abiotic surfaces, with serious implications for applications that rely on prolonged exposure to the body such as implantable biomedical devices or catheters. Therefore, there is an urgent need to develop improved therapeutics to effectively eradicate unwanted biofilms. Recently, the biological signaling molecule nitric oxide (NO) was identified as a key regulator of dispersal events in biofilms. In this paper, we report a new class of core cross-linked star polymers designed to store and release nitric oxide, in a controlled way, for the dispersion of biofilms. First, core cross-linked star polymers were prepared by reversible addition-fragmentation chain transfer polymerization (RAFT) via an arm first approach. Poly(oligoethylene methoxy acrylate) chains were synthesized by RAFT polymerization, and then chain extended in the presence of 2-vinyl-4,4-dimethyl-5-oxazolone monomer (VDM) with N,N-methylenebis(acrylamide) employed as a cross-linker to yield functional core cross-linked star polymers. Spermine was successfully attached to the star core by reaction with VDM. Finally, the secondary amine groups were reacted with NO gas to yield NO-core cross-linked star polymers. The core cross-linked star polymers were found to release NO in a controlled, slow delivery in bacterial cultures showing great efficacy in preventing both cell attachment and biofilm formation in Pseudomonas aeruginosa over time via a nontoxic mechanism, confining bacterial growth to the suspended liquid.
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Maltodextrin enhances biofilm elimination by electrochemical scaffold
Sultana, Sujala T.; Call, Douglas R.; Beyenal, Haluk
2016-01-01
Electrochemical scaffolds (e-scaffolds) continuously generate low concentrations of H2O2 suitable for damaging wound biofilms without damaging host tissue. Nevertheless, retarded diffusion combined with H2O2 degradation can limit the efficacy of this potentially important clinical tool. H2O2 diffusion into biofilms and bacterial cells can be increased by damaging the biofilm structure or by activating membrane transportation channels by exposure to hyperosmotic agents. We hypothesized that e-scaffolds would be more effective against Acinetobacter baumannii and Staphylococcus aureus biofilms in the presence of a hyperosmotic agent. E-scaffolds polarized at −600 mVAg/AgCl were overlaid onto preformed biofilms in media containing various maltodextrin concentrations. E-scaffold alone decreased A. baumannii and S. aureus biofilm cell densities by (3.92 ± 0.15) log and (2.31 ± 0.12) log, respectively. Compared to untreated biofilms, the efficacy of the e-scaffold increased to a maximum (8.27 ± 0.05) log reduction in A. baumannii and (4.71 ± 0.12) log reduction in S. aureus biofilm cell densities upon 10 mM and 30 mM maltodextrin addition, respectively. Overall ~55% decrease in relative biofilm surface coverage was achieved for both species. We conclude that combined treatment with electrochemically generated H2O2 from an e-scaffold and maltodextrin is more effective in decreasing viable biofilm cell density. PMID:27782161
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Biofilm-specific extracellular matrix proteins of nontypeable Haemophilus influenzae.
Wu, Siva; Baum, Marc M; Kerwin, James; Guerrero, Debbie; Webster, Simon; Schaudinn, Christoph; VanderVelde, David; Webster, Paul
2014-12-01
Nontypeable Haemophilus influenzae (NTHi), a human respiratory tract pathogen, can form colony biofilms in vitro. Bacterial cells and the amorphous extracellular matrix (ECM) constituting the biofilm can be separated using sonication. The ECM from 24- and 96-h NTHi biofilms contained polysaccharides and proteinaceous components as detected by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) spectroscopy. More conventional chemical assays on the biofilm ECM confirmed the presence of these components and also DNA. Proteomics revealed eighteen proteins present in biofilm ECM that were not detected in planktonic bacteria. One ECM protein was unique to 24-h biofilms, two were found only in 96-h biofilms, and fifteen were present in the ECM of both 24- and 96-h NTHi biofilms. All proteins identified were either associated with bacterial membranes or cytoplasmic proteins. Immunocytochemistry showed two of the identified proteins, a DNA-directed RNA polymerase and the outer membrane protein OMP P2, associated with bacteria and biofilm ECM. Identification of biofilm-specific proteins present in immature biofilms is an important step in understanding the in vitro process of NTHi biofilm formation. The presence of a cytoplasmic protein and a membrane protein in the biofilm ECM of immature NTHi biofilms suggests that bacterial cell lysis may be a feature of early biofilm formation. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.
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Hille, Andrea; He, Mei; Ochmann, Clemens; Neu, Thomas R; Horn, Harald
2009-01-01
Two component biodegradable carriers for biofilm airlift suspension (BAS) reactors were investigated with respect to development of biofilm structure and oxygen transport inside the biofilm. The carriers were composed of PHB (polyhydroxybutyrate), which is easily degradable and PCL (caprolactone), which is less easily degradable by heterotrophic microorganisms. Cryosectioning combined with classical light microscopy and CLSM was used to identify the surface structure of the carrier material over a period of 250 days of biofilm cultivation in an airlift reactor. Pores of 50 to several hundred micrometers depth are formed due to the preferred degradation of PHB. Furthermore, microelectrode studies show the transport mechanism for different types of biofilm structures, which were generated under different substrate conditions. At high loading rates, the growth of a rather loosely structured biofilm with high penetration depths of oxygen was found. Strong changes of substrate concentration during fed-batch mode operation of the reactor enhance the growth of filamentous biofilms on the carriers. Mass transport in the outer regions of such biofilms was mainly driven by advection.
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High Biofilm Conductivity Maintained Despite Anode Potential Changes in a Geobacter-Enriched Biofilm
This study systematically assessed intracellular electron transfer (IET) and extracellular electron transfer (EET) kinetics with respect to anode potential (Eanode) in a mixed-culture biofilm anode enriched with Geobacter spp. High biofilm conductivity (0.96–1.24 mScm^-1) was mai...
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Bacterial Biofilms as Complex Communities
NASA Astrophysics Data System (ADS)
Vlamakis, Hera
2010-03-01
Many microbial populations form surface-associated multicellular communities known as biofilms. These multicellular communities are encased in a self-produced extracellular matrix composed of polysaccharides and proteins. Division of labor is a key feature of these communities and different cells serve distinct functions. We have found that in biofilms of the bacterium Bacillus subtilis, different cell types including matrix-producing and sporulating cells coexist and localize to distinct regions within the structured community. We were interested in understanding how these different cell types arise. Using fluorescence reporters under the control of promoters that are specific for distinct cell types we were able to follow the dynamics of differentiation throughout biofilm development. We found that a series of extracellular signals leads to differentiation of distinct cell types during biofilm formation. In addition, we found that extracellular matrix functions as a differentiation signal for timely sporulation within a biofilm and mutants unable to produce matrix were delayed in sporulation. Our results indicate that within a biofilm, cell-cell signaling is directional in that one cell type produces a signal that is sensed by another distinct cell type. Furthermore, once differentiated, cells become resistant to the action of other signaling molecules making it possible to maintain distinct cell populations over prolonged periods.
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Sun, Lingmei; Liao, Kai; Wang, Dayong
2015-01-01
The first step in infection by Candida albicans is adhesion to host cells or implanted medical devices and this followed by hyphal growth and biofilm formation. Yeast-to-hyphal transition has long been identified as a key factor in fungal virulence. Following biofilm formation, C. albicans is usually less sensitive or insensitive to antifungals. Therefore, development of new antifungals with inhibitory action on adhesion, yeast-hyphal transition and biofilm formation by C. albicans is very necessary. The effects of magnolol and honokiol on hypha growth were investigated using different induction media. Their inhibitory effects were determined using the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5- carboxanilide assay, and biofilm thickness and viability were observed by a confocal scanning laser microscope. Mammalian cells were used in adhesion assays. Genes related to hyphae development and cell adhesions were analyzed by real-time reverse transcription-polymerase chain reaction. The exogenous cyclic adenosine monophosphate was used to determine the mechanisms of action of magnolol and honokiol. Caenorhabditis elegans was used as an in vivo model to estimate the antifungal activities of magnolol and honokiol. Magnolol and honokiol inhibited adhesion, the transition from yeast to hypha, and biofilm formation by C. albicans through the Ras1-cAMP-Efg1 pathway. Moreover, magnolol and honokiol prolonged the survival of nematodes infected by C. albicans. Magnolol and honokiol have potential inhibitory effects against biofilm formation by C. albicans. This study provides useful information towards the development of new strategies to reduce the incidence of C. albicans biofilm-associated infection.
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Effects of biofilm on river-bed scour.
Piqué, Gemma; Vericat, Damià; Sabater, Sergi; Batalla, Ramon J
2016-12-01
Biofilm acts stabilising river-bed sediments, interfering with particle entrainment and, consequently, preventing bed disturbance. In this paper we present the results of a series of experiments carried out in indoor channels, aimed to understand biofilm alteration of bed material motion and topographic changes in stream channels. We analysed the erosion patterns and bedload rates in non-cohesive sediments in channels colonised by biofilms and compared them to biofilm-free others. All the channels had the same conditions of light irradiance, temperature, slope, and particle size (sand). Discharge and water surface slope were modified to create a range of hydraulic conditions, with pairs of colonised and non-colonised channels subjected to the same flows. We observed that biofilm slightly modified bed roughness and flow hydraulics, but that highly influenced bed disturbance. Biofilm caused bed scour to occur in patches unevenly distributed along the channel length, as a result of localised weaknesses of the biofilm. Once biofilm was ripped up it was transported in chunks, and sand grains were observed attached to these chunks. In non-colonised sediments the erosion was more homogeneous and the formation and movement of bedforms were observed. On average, bedload rates were 5 times lower when biofilm was present. Overall, the protective effect of the biofilm prevented generalised erosion of the channel and delayed the entrainment and transport of sand grains. Results emphasised the important role of biofilm in the incipient motion of bed-material in stream channels; this role may affect the magnitude and frequency of subsequent river bed processes, notably the onset of bedload and associated channel morpho-dynamics. Copyright © 2016 Elsevier B.V. All rights reserved.
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Günther, F; Scherrer, M; Kaiser, S J; DeRosa, A; Mutters, N T
2017-03-01
The aim of our study was to develop a new reproducible method for disinfectant efficacy testing on bacterial biofilms and to evaluate the efficacy of different disinfectants against biofilms. Clinical multidrug-resistant strains were chosen as test isolates to ensure practical relevance. We compared the standard qualitative suspension assay for disinfectant testing, which does not take into account biofilm formation, to the new biofilm viability assay that uses kinetic analysis of metabolic activity in biofilms after disinfectant exposure to evaluate disinfectant efficacy. In addition, the efficacy of four standard disinfectants to clinical isolates was tested using both methods. All tested disinfectants were effective against test isolates when in planktonic state using the standard qualitative suspension assay, while disinfectants were only weakly effective against bacteria in biofilms. Disinfectant efficacy testing on planktonic organisms ignores biofilms and overestimates disinfectant susceptibility of bacteria. However, biofilm forming, e.g. on medical devices or hospital surfaces, is the natural state of bacterial living and needs to be considered in disinfectant testing. Although bacterial biofilms are the predominant manner of bacterial colonization, most standard procedures for antimicrobial susceptibility testing and efficacy testing of disinfectants are adapted for application to planktonic bacteria. To our knowledge, this is the first study to use a newly developed microplate-based biofilm test system that uses kinetic analysis of the metabolic activity in biofilms, after disinfectant exposure, to evaluate disinfectant efficacy. Our study shows that findings obtained from disinfectant efficacy testing on planktonic bacteria cannot be extrapolated to predict disinfectant efficacy on bacterial biofilms of clinically relevant multidrug-resistant organisms. © 2016 The Society for Applied Microbiology.
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Qu, Yue; Locock, Katherine; Verma-Gaur, Jiyoti; Hay, Iain D; Meagher, Laurence; Traven, Ana
2016-02-01
Biofilm-related human infections have high mortality rates due to drug resistance. Cohabitation of diverse microbes in polymicrobial biofilms is common and these infections present additional challenges for treatment compared with monomicrobial biofilms. Here, we address this therapeutic gap by assessing the potential of a new class of antimicrobial agents, guanylated polymethacrylates, in the treatment of polymicrobial biofilms built by two prominent human pathogens, the fungus Candida albicans and the bacterium Staphylococcus aureus. We used imaging and quantitative methods to test the antibiofilm efficacy of guanylated polymethacrylates, a new class of drugs that structurally mimic antimicrobial peptides. We further compared guanylated polymethacrylates with first-line antistaphylococcal and anti-Candida agents used as combinatorial therapy against polymicrobial biofilms. Guanylated polymethacrylates were highly effective as a sole agent, killing both C. albicans and S. aureus when applied to established polymicrobial biofilms. Furthermore, they outperformed multiple combinations of current antimicrobial drugs, with one of the tested compounds killing 99.98% of S. aureus and 82.2% of C. albicans at a concentration of 128 mg/L. The extracellular biofilm matrix provided protection, increasing the MIC of the polymethacrylates by 2-4-fold when added to planktonic assays. Using the C. albicans bgl2ΔΔ mutant, we implicate matrix polysaccharide β-1,3 glucan in the mechanism of protection. Data for two structurally distinct polymers suggest that this mechanism could be minimized through chemical optimization of the polymer structure. Finally, we demonstrate that a potential application for these polymers is in antimicrobial lock therapy. Guanylated polymethacrylates are a promising lead for the development of an effective monotherapy against C. albicans/S. aureus polymicrobial biofilms. © The Author 2015. Published by Oxford University Press on behalf of the British
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Cavaliere, Rosalia; Ball, Jessica L; Turnbull, Lynne; Whitchurch, Cynthia B
2014-01-01
Nontypeable Hemophilus influenzae (NTHi) is a Gram-negative bacterial pathogen that causes chronic biofilm infections of the ears and airways. The biofilm matrix provides structural integrity to the biofilm and protects biofilm cells from antibiotic exposure by reducing penetration of antimicrobial compounds into the biofilm. Extracellular DNA (eDNA) has been found to be a major matrix component of biofilms formed by many species of Gram-positive and Gram-negative bacteria, including NTHi. Interestingly, the cation chelator ethylenediaminetetra-acetic acid (EDTA) has been shown to reduce the matrix strength of biofilms of several bacterial species as well as to have bactericidal activity against various pathogens. EDTA exerts its antimicrobial activity by chelating divalent cations necessary for growth and membrane stability and by destabilizing the matrix thus enhancing the detachment of bacterial cells from the biofilm. In this study, we have explored the role of divalent cations in NTHi biofilm development and stability. We have utilized in vitro static and continuous flow models of biofilm development by NTHi to demonstrate that magnesium cations enhance biofilm formation by NTHi. We found that the divalent cation chelator EDTA is effective at both preventing NTHi biofilm formation and at treating established NTHi biofilms. Furthermore, we found that the matrix destablilizers EDTA and DNaseI increase the susceptibility of NTHi biofilms to ampicillin and ciprofloxacin. Our observations indicate that DNaseI and EDTA enhance the efficacy of antibiotic treatment of NTHi biofilms. These observations may lead to new strategies that will improve the treatment options available to patients with chronic NTHi infections. PMID:25044339
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NASA Astrophysics Data System (ADS)
Volk, Elazar; Iden, Sascha C.; Furman, Alex; Durner, Wolfgang; Rosenzweig, Ravid
2016-08-01
Understanding the influence of attached microbial biomass on water flow in variably saturated soils is crucial for many engineered flow systems. So far, the investigation of the effects of microbial biomass has been mainly limited to water-saturated systems. We have assessed the influence of biofilms on the soil hydraulic properties under variably saturated conditions. A sandy soil was incubated with Pseudomonas Putida and the hydraulic properties of the incubated soil were determined by a combination of methods. Our results show a stronger soil water retention in the inoculated soil as compared to the control. The increase in volumetric water content reaches approximately 0.015 cm3 cm-3 but is only moderately correlated with the carbon deficit, a proxy for biofilm quantity, and less with the cell viable counts. The presence of biofilm reduced the saturated hydraulic conductivity of the soil by up to one order of magnitude. Under unsaturated conditions, the hydraulic conductivity was only reduced by a factor of four. This means that relative water conductance in biofilm-affected soils is higher compared to the clean soil at low water contents, and that the unsaturated hydraulic conductivity curve of biofilm-affected soil cannot be predicted by simply scaling the saturated hydraulic conductivity. A flexible parameterization of the soil hydraulic functions accounting for capillary and noncapillary flow was needed to adequately describe the observed properties over the entire wetness range. More research is needed to address the exact flow mechanisms in biofilm-affected, unsaturated soil and how they are related to effective system properties.
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Clark, Melinda E; He, Zhili; Redding, Alyssa M; Joachimiak, Marcin P; Keasling, Jay D; Zhou, Jizhong Z; Arkin, Adam P; Mukhopadhyay, Aindrila; Fields, Matthew W
2012-04-16
Desulfovibrio vulgaris Hildenborough is a sulfate-reducing bacterium (SRB) that is intensively studied in the context of metal corrosion and heavy-metal bioremediation, and SRB populations are commonly observed in pipe and subsurface environments as surface-associated populations. In order to elucidate physiological changes associated with biofilm growth at both the transcript and protein level, transcriptomic and proteomic analyses were done on mature biofilm cells and compared to both batch and reactor planktonic populations. The biofilms were cultivated with lactate and sulfate in a continuously fed biofilm reactor, and compared to both batch and reactor planktonic populations. The functional genomic analysis demonstrated that biofilm cells were different compared to planktonic cells, and the majority of altered abundances for genes and proteins were annotated as hypothetical (unknown function), energy conservation, amino acid metabolism, and signal transduction. Genes and proteins that showed similar trends in detected levels were particularly involved in energy conservation such as increases in an annotated ech hydrogenase, formate dehydrogenase, pyruvate:ferredoxin oxidoreductase, and rnf oxidoreductase, and the biofilm cells had elevated formate dehydrogenase activity. Several other hydrogenases and formate dehydrogenases also showed an increased protein level, while decreased transcript and protein levels were observed for putative coo hydrogenase as well as a lactate permease and hyp hydrogenases for biofilm cells. Genes annotated for amino acid synthesis and nitrogen utilization were also predominant changers within the biofilm state. Ribosomal transcripts and proteins were notably decreased within the biofilm cells compared to exponential-phase cells but were not as low as levels observed in planktonic, stationary-phase cells. Several putative, extracellular proteins (DVU1012, 1545) were also detected in the extracellular fraction from biofilm cells
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2012-01-01
Background Desulfovibrio vulgaris Hildenborough is a sulfate-reducing bacterium (SRB) that is intensively studied in the context of metal corrosion and heavy-metal bioremediation, and SRB populations are commonly observed in pipe and subsurface environments as surface-associated populations. In order to elucidate physiological changes associated with biofilm growth at both the transcript and protein level, transcriptomic and proteomic analyses were done on mature biofilm cells and compared to both batch and reactor planktonic populations. The biofilms were cultivated with lactate and sulfate in a continuously fed biofilm reactor, and compared to both batch and reactor planktonic populations. Results The functional genomic analysis demonstrated that biofilm cells were different compared to planktonic cells, and the majority of altered abundances for genes and proteins were annotated as hypothetical (unknown function), energy conservation, amino acid metabolism, and signal transduction. Genes and proteins that showed similar trends in detected levels were particularly involved in energy conservation such as increases in an annotated ech hydrogenase, formate dehydrogenase, pyruvate:ferredoxin oxidoreductase, and rnf oxidoreductase, and the biofilm cells had elevated formate dehydrogenase activity. Several other hydrogenases and formate dehydrogenases also showed an increased protein level, while decreased transcript and protein levels were observed for putative coo hydrogenase as well as a lactate permease and hyp hydrogenases for biofilm cells. Genes annotated for amino acid synthesis and nitrogen utilization were also predominant changers within the biofilm state. Ribosomal transcripts and proteins were notably decreased within the biofilm cells compared to exponential-phase cells but were not as low as levels observed in planktonic, stationary-phase cells. Several putative, extracellular proteins (DVU1012, 1545) were also detected in the extracellular fraction from
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Klare, William; Das, Theerthankar; Ibugo, Amaye; Buckle, Edwina; Manefield, Mike; Manos, Jim
2016-08-01
Pseudomonas aeruginosa infections result in high morbidity and mortality rates for individuals with cystic fibrosis (CF), with premature death often occurring. These infections are complicated by the formation of biofilms in the sputum. Antibiotic therapy is stymied by antibiotic resistance of the biofilm matrix, making novel antibiofilm strategies highly desirable. Within P. aeruginosa biofilms, the redox factor pyocyanin enhances biofilm integrity by intercalating with extracellular DNA. The antioxidant glutathione (GSH) reacts with pyocyanin, disrupting intercalation. This study investigated GSH disruption by assaying the physiological effects of GSH and DNase I on biofilms of clinical CF isolates grown in CF artificial sputum medium (ASMDM+). Confocal scanning laser microscopy showed that 2 mM GSH, alone or combined with DNase I, significantly disrupted immature (24-h) biofilms of Australian epidemic strain (AES) isogens AES-1R and AES-1M. GSH alone greatly disrupted mature (72-h) AES-1R biofilms, resulting in significant differential expression of 587 genes, as indicated by RNA-sequencing (RNA-seq) analysis. Upregulated systems included cyclic diguanylate and pyoverdine biosynthesis, the type VI secretion system, nitrate metabolism, and translational machinery. Biofilm disruption with GSH revealed a cellular physiology distinct from those of mature and dispersed biofilms. RNA-seq results were validated by biochemical and quantitative PCR assays. Biofilms of a range of CF isolates disrupted with GSH and DNase I were significantly more susceptible to ciprofloxacin, and increased antibiotic effectiveness was achieved by increasing the GSH concentration. This study demonstrated that GSH, alone or with DNase I, represents an effective antibiofilm treatment when combined with appropriate antibiotics, pending in vivo studies. Copyright © 2016, American Society for Microbiology. All Rights Reserved.
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Das, Theerthankar; Ibugo, Amaye; Buckle, Edwina; Manefield, Mike; Manos, Jim
2016-01-01
Pseudomonas aeruginosa infections result in high morbidity and mortality rates for individuals with cystic fibrosis (CF), with premature death often occurring. These infections are complicated by the formation of biofilms in the sputum. Antibiotic therapy is stymied by antibiotic resistance of the biofilm matrix, making novel antibiofilm strategies highly desirable. Within P. aeruginosa biofilms, the redox factor pyocyanin enhances biofilm integrity by intercalating with extracellular DNA. The antioxidant glutathione (GSH) reacts with pyocyanin, disrupting intercalation. This study investigated GSH disruption by assaying the physiological effects of GSH and DNase I on biofilms of clinical CF isolates grown in CF artificial sputum medium (ASMDM+). Confocal scanning laser microscopy showed that 2 mM GSH, alone or combined with DNase I, significantly disrupted immature (24-h) biofilms of Australian epidemic strain (AES) isogens AES-1R and AES-1M. GSH alone greatly disrupted mature (72-h) AES-1R biofilms, resulting in significant differential expression of 587 genes, as indicated by RNA-sequencing (RNA-seq) analysis. Upregulated systems included cyclic diguanylate and pyoverdine biosynthesis, the type VI secretion system, nitrate metabolism, and translational machinery. Biofilm disruption with GSH revealed a cellular physiology distinct from those of mature and dispersed biofilms. RNA-seq results were validated by biochemical and quantitative PCR assays. Biofilms of a range of CF isolates disrupted with GSH and DNase I were significantly more susceptible to ciprofloxacin, and increased antibiotic effectiveness was achieved by increasing the GSH concentration. This study demonstrated that GSH, alone or with DNase I, represents an effective antibiofilm treatment when combined with appropriate antibiotics, pending in vivo studies. PMID:27161630
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Ansari, M A; Khan, H M; Khan, A A; Cameotra, S S; Alzohairy, M A
2015-01-01
Different approaches have been used for preventing biofilm-related infections in health care settings. Many of these methods have their own de-merits, which include chemical-based complications; emergent antibiotic resistant strains, etc. The formation of biofilm is the hallmark characteristic of Staphylococcus aureus and S. epidermidis infection, which consists of multiple layers of bacteria encased within an exopolysachharide glycocalyx. Nanotechnology may provide the answer to penetrate such biofilms and reduce biofilm formation. Therefore, the aim of present study was to demonstrate the biofilm formation by methicillin resistance S. aureus (MRSA) and methicillin resistance S. epidermidis (MRSE) isolated from wounds by direct visualisation applying tissue culture plate, tube and Congo Red Agar methods. The anti-biofilm activity of AgNPs was investigated by Congo Red, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) techniques. The minimum inhibitory concentration (MIC) was found to be in the range of 11.25-45 μg/ml. The AgNPs coated surfaces effectively restricted biofilm formation of the tested bacteria. Double fluorescent staining (propidium iodide staining to detect bacterial cells and fluorescein isothiocyanate concanavalin A (Con A-FITC) staining to detect the exopolysachharides matrix) technique using CLSM provides the visual evidence that AgNPs arrested the bacterial growth and prevent the glycocalyx formation. In our study, we could demonstrate the complete anti-biofilm activity AgNPs at a concentration as low as 50 μg/ml. Our findings suggested that AgNPs can be exploited towards the development of potential anti-bacterial coatings for various biomedical and environmental applications. In the near future, the AgNPs may play major role in the coating of medical devices and treatment of infections caused due to highly antibiotic resistant biofilm.
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Pseudomonas biofilm matrix composition and niche biology
Mann, Ethan E.; Wozniak, Daniel J.
2014-01-01
Biofilms are a predominant form of growth for bacteria in the environment and in the clinic. Critical for biofilm development are adherence, proliferation, and dispersion phases. Each of these stages includes reinforcement by, or modulation of, the extracellular matrix. Pseudomonas aeruginosa has been a model organism for the study of biofilm formation. Additionally, other Pseudomonas species utilize biofilm formation during plant colonization and environmental persistence. Pseudomonads produce several biofilm matrix molecules, including polysaccharides, nucleic acids, and proteins. Accessory matrix components shown to aid biofilm formation and adaptability under varying conditions are also produced by pseudomonads. Adaptation facilitated by biofilm formation allows for selection of genetic variants with unique and distinguishable colony morphology. Examples include rugose small-colony variants and wrinkly spreaders (WS), which over produce Psl/Pel or cellulose, respectively, and mucoid bacteria that over produce alginate. The well-documented emergence of these variants suggests that pseudomonads take advantage of matrix-building subpopulations conferring specific benefits for the entire population. This review will focus on various polysaccharides as well as additional Pseudomonas biofilm matrix components. Discussions will center on structure–function relationships, regulation, and the role of individual matrix molecules in niche biology. PMID:22212072
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Biofilms inducing ultra-low friction on titanium.
Souza, J C M; Henriques, M; Oliveira, R; Teughels, W; Celis, J-P; Rocha, L A
2010-12-01
Biofilm formation is widely reported in the literature as a problem in the healthcare, environmental, and industrial sectors. However, the role of biofilms in sliding contacts remains unclear. Friction during sliding was analyzed for titanium covered with mixed biofilms consisting of Streptococcus mutans and Candida albicans. The morphology of biofilms on titanium surfaces was evaluated before, during, and after sliding tests. Very low friction was recorded on titanium immersed in artificial saliva and sliding against alumina in the presence of biofilms. The complex structure of biofilms, which consist of microbial cells and their hydrated exopolymeric matrix, acts like a lubricant. A low friction in sliding contacts may have major significance in the medical field. The composition and structure of biofilms are shown to be key factors for an understanding of friction behavior of dental implant connections and prosthetic joints. For instance, a loss of mechanical integrity of dental implant internal connections may occur as a consequence of the decrease in friction caused by biofilm formation. Consequently, the study of the exopolymeric matrix can be important for the development of high-performance novel joint-based systems for medical and other engineering applications.
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Biological synthesis of nanoparticles in biofilms.
Tanzil, Abid H; Sultana, Sujala T; Saunders, Steven R; Shi, Liang; Marsili, Enrico; Beyenal, Haluk
2016-12-01
The biological synthesis of nanoparticles (NPs) by bacteria and biofilms via extracellular redox reactions has received attention because of the minimization of harmful chemicals, low cost, and ease of culturing and downstream processing. Bioreduction mechanisms vary across bacteria and growth conditions, which leads to various sizes and shapes of biosynthesized NPs. NP synthesis in biofilms offers additional advantages, such as higher biomass concentrations and larger surface areas, which can lead to more efficient and scalable biosynthesis. Although biofilms have been used to produce NPs, the mechanistic details of NP formation are not well understood. In this review, we identify three critical areas of research and development needed to advance our understanding of NP production by biofilms: 1) synthesis, 2) mechanism and 3) stabilization. Advancement in these areas could result in the biosynthesis of NPs that are suitable for practical applications, especially in drug delivery and biocatalysis. Specifically, the current status of methods and mechanisms of nanoparticle synthesis and surface stabilization using planktonic bacteria and biofilms is discussed. We conclude that the use of biofilms to synthesize and stabilize NPs is underappreciated and could provide a new direction in biofilm-based NP production. Copyright © 2016 Elsevier Inc. All rights reserved.
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AFM Structural Characterization of Drinking Water Biofilm ...
Due to the complexity of mixed culture drinking water biofilm, direct visual observation under in situ conditions has been challenging. In this study, atomic force microscopy (AFM) revealed the three dimensional morphology and arrangement of drinking water relevant biofilm in air and aqueous solution. Operating parameters were optimized to improve imaging of structural details for a mature biofilm in liquid. By using a soft cantilever (0.03 N/m) and slow scan rate (0.5 Hz), biofilm and individual bacterial cell’s structural topography were resolved and continuously imaged in liquid without loss of spatial resolution or sample damage. The developed methodology will allow future in situ investigations to temporally monitor mixed culture drinking water biofilm structural changes during disinfection treatments. Due to the complexity of mixed culture drinking water biofilm, direct visual observation under in situ conditions has been challenging. In this study, atomic force microscopy (AFM) revealed the three dimensional morphology and arrangement of drinking water relevant biofilm in air and aqueous solution. Operating parameters were optimized to improve imaging of structural details for a mature biofilm in liquid. By using a soft cantilever (0.03 N/m) and slow scan rate (0.5 Hz), biofilm and individual bacterial cell’s structural topography were resolved and continuously imaged in liquid without loss of spatial resolution or sample damage. The developed methodo
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Cavaliere, Rosalia; Ball, Jessica L; Turnbull, Lynne; Whitchurch, Cynthia B
2014-08-01
Nontypeable Hemophilus influenzae (NTHi) is a Gram-negative bacterial pathogen that causes chronic biofilm infections of the ears and airways. The biofilm matrix provides structural integrity to the biofilm and protects biofilm cells from antibiotic exposure by reducing penetration of antimicrobial compounds into the biofilm. Extracellular DNA (eDNA) has been found to be a major matrix component of biofilms formed by many species of Gram-positive and Gram-negative bacteria, including NTHi. Interestingly, the cation chelator ethylenediaminetetra-acetic acid (EDTA) has been shown to reduce the matrix strength of biofilms of several bacterial species as well as to have bactericidal activity against various pathogens. EDTA exerts its antimicrobial activity by chelating divalent cations necessary for growth and membrane stability and by destabilizing the matrix thus enhancing the detachment of bacterial cells from the biofilm. In this study, we have explored the role of divalent cations in NTHi biofilm development and stability. We have utilized in vitro static and continuous flow models of biofilm development by NTHi to demonstrate that magnesium cations enhance biofilm formation by NTHi. We found that the divalent cation chelator EDTA is effective at both preventing NTHi biofilm formation and at treating established NTHi biofilms. Furthermore, we found that the matrix destablilizers EDTA and DNaseI increase the susceptibility of NTHi biofilms to ampicillin and ciprofloxacin. Our observations indicate that DNaseI and EDTA enhance the efficacy of antibiotic treatment of NTHi biofilms. These observations may lead to new strategies that will improve the treatment options available to patients with chronic NTHi infections. © 2014 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.
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APPLICATIONS OF BIOTECHNOLOGY IN DEVELOPMENT OF BIOMATERIALS: NANOTECHNOLOGY AND BIOFILMS
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brigmon, R.; Berry, T.; Narayan, R.
2010-11-29
Biotechnology is the application of biological techniques to develop new tools and products for medicine and industry. Due to various properties including chemical stability, biocompatibility, and specific activity, e.g. antimicrobial properties, many new and novel materials are being investigated for use in biosensing, drug delivery, hemodialysis, and other medical applications. Many of these materials are less than 100 nanometers in size. Nanotechnology is the engineering discipline encompassing designing, producing, testing, and using structures and devices less than 100 nanometers. One of the challenges associated with biomaterials is microbial contamination that can lead to infections. In recent work we have examinedmore » the functionalization of nanoporous biomaterials and antimicrobial activities of nanocrystalline diamond materials. In vitro testing has revealed little antimicrobial activity against Pseudomonas fluorescens bacteria and associated biofilm formation that enhances recalcitrance to antimicrobial agents including disinfectants and antibiotics. Laser scanning confocal microscopy studies further demonstrated properties and characteristics of the material with regard to biofilm formation.« less
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Kinetic Theories for Biofilms (Preprint)
2011-01-01
2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Kinetic Theories for Biofilms 5a. CONTRACT NUMBER 5b...binary complex fluids to develop a set of hydrodynamic models for the two-phase mixture of biofilms and solvent (water). It is aimed to model...kinetics along with the intrinsic molecular elasticity of the EPS network strand modeled as an elastic dumbbell. This theory is valid in both the biofilm
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Analysis of the biofilm proteome of Xylella fastidiosa.
Silva, Mariana S; De Souza, Alessandra A; Takita, Marco A; Labate, Carlos A; Machado, Marcos A
2011-09-22
Xylella fastidiosa is limited to the xylem of the plant host and the foregut of insect vectors (sharpshooters). The mechanism of pathogenicity of this bacterium differs from other plant pathogens, since it does not present typical genes that confer specific interactions between plant and pathogens (avr and/or hrp). The bacterium is injected directly into the xylem vessels where it adheres and colonizes. The whole process leads to the formation of biofilms, which are considered the main mechanism of pathogenicity. Cells in biofilms are metabolically and phenotypically different from their planktonic condition. The mature biofilm stage (phase of higher cell density) presents high virulence and resistance to toxic substances such as antibiotics and detergents. Here we performed proteomic analysis of proteins expressed exclusively in the mature biofilm of X. fastidiosa strain 9a5c, in comparison to planktonic growth condition. We found a total of 456 proteins expressed in the biofilm condition, which correspond to approximately 10% of total protein in the genome. The biofilm showed 37% (or 144 proteins) different protein than we found in the planktonic growth condition. The large difference in protein pattern in the biofilm condition may be responsible for the physiological changes of the cells in the biofilm of X. fastidiosa. Mass spectrometry was used to identify these proteins, while real-time quantitative polymerase chain reaction monitored expression of genes encoding them. Most of proteins expressed in the mature biofilm growth were associated with metabolism, adhesion, pathogenicity and stress conditions. Even though the biofilm cells in this work were not submitted to any stress condition, some stress related proteins were expressed only in the biofilm condition, suggesting that the biofilm cells would constitutively express proteins in different adverse environments. We observed overexpression of proteins related to quorum sensing, proving the existence of
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Analysis of the biofilm proteome of Xylella fastidiosa
2011-01-01
Background Xylella fastidiosa is limited to the xylem of the plant host and the foregut of insect vectors (sharpshooters). The mechanism of pathogenicity of this bacterium differs from other plant pathogens, since it does not present typical genes that confer specific interactions between plant and pathogens (avr and/or hrp). The bacterium is injected directly into the xylem vessels where it adheres and colonizes. The whole process leads to the formation of biofilms, which are considered the main mechanism of pathogenicity. Cells in biofilms are metabolically and phenotypically different from their planktonic condition. The mature biofilm stage (phase of higher cell density) presents high virulence and resistance to toxic substances such as antibiotics and detergents. Here we performed proteomic analysis of proteins expressed exclusively in the mature biofilm of X. fastidiosa strain 9a5c, in comparison to planktonic growth condition. Results We found a total of 456 proteins expressed in the biofilm condition, which correspond to approximately 10% of total protein in the genome. The biofilm showed 37% (or 144 proteins) different protein than we found in the planktonic growth condition. The large difference in protein pattern in the biofilm condition may be responsible for the physiological changes of the cells in the biofilm of X. fastidiosa. Mass spectrometry was used to identify these proteins, while real-time quantitative polymerase chain reaction monitored expression of genes encoding them. Most of proteins expressed in the mature biofilm growth were associated with metabolism, adhesion, pathogenicity and stress conditions. Even though the biofilm cells in this work were not submitted to any stress condition, some stress related proteins were expressed only in the biofilm condition, suggesting that the biofilm cells would constitutively express proteins in different adverse environments. Conclusions We observed overexpression of proteins related to quorum
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Effects of Miramistin and Phosprenil on Microbial Biofilms.
Danilova, T A; Danilina, G A; Adzhieva, A A; Minko, A G; Nikolaeva, T N; Zhukhovitskii, V G; Pronin, A V
2017-08-01
Effects of Miramistin and Phosprenil on biofilms of S. pyogenes, S. aureus, E. coli, L. acidophilus, and L. plantarum were studied. Significant differences in the effects of these substances on mature biofilms of microorganisms and the process of their formation were observed. Miramistin had significant inhibiting effects on the forming of biofilms and on the formed biofilms of all studied microorganisms. Treatment with Miramistin inhibited biofilm formation by 2-3 times compared to the control. This effect was found already after using of Miramistin in the low doses (3.12 μg/ml). Inhibition of the growth of a formed biofilm was observed only after treatment with Miramistin in the high doses (25-50 μg/ml). Phosprenil in the high doses (15-30 mg/ml) inhibited the forming of biofilms, especially the biofilms of S. pyogenes and L. plantarum (by 3-4.5 times). Treatment of formed biofilms with the agent in doses of 6.0 and 0.6 mg/ml was associated with pronounced stimulation of its growth in S. pyogenes, S. aureus, and L. acidophilus.
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Kong, Eric F; Tsui, Christina; Kucharíková, Sona; Andes, David; Van Dijck, Patrick; Jabra-Rizk, Mary Ann
2016-10-11
Biofilm-associated polymicrobial infections, particularly those involving fungi and bacteria, are responsible for significant morbidity and mortality and tend to be challenging to treat. Candida albicans and Staphylococcus aureus specifically are considered leading opportunistic fungal and bacterial pathogens, respectively, mainly due to their ability to form biofilms on catheters and indwelling medical devices. However, the impact of mixed-species biofilm growth on therapy remains largely understudied. In this study, we investigated the influence of C. albicans secreted cell wall polysaccharides on the response of S. aureus to antibacterial agents in biofilm. Results demonstrated significantly enhanced tolerance for S. aureus to drugs in the presence of C. albicans or its secreted cell wall polysaccharide material. Fluorescence confocal time-lapse microscopy revealed impairment of drug diffusion through the mixed biofilm matrix. Using C. albicans mutant strains with modulated cell wall polysaccharide expression, exogenous supplementation, and enzymatic degradation, the C. albicans-secreted β-1,3-glucan cell wall component was identified as the key matrix constituent providing the bacteria with enhanced drug tolerance. Further, antibody labeling demonstrated rapid coating of the bacteria by the C. albicans matrix material. Importantly, via its effect on the fungal biofilm matrix, the antifungal caspofungin sensitized the bacteria to the drugs. Understanding such symbiotic interactions with clinical relevance between microbial species in biofilms will greatly aid in overcoming the limitations of current therapies and in defining potential new targets for treating polymicrobial infections. The fungus Candida albicans and the bacterium Staphylococcus aureus are important microbial pathogens responsible for the majority of infections in hospitalized patients and are often coisolated from a host. In this study, we demonstrated that when grown together, the
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Differential growth of wrinkled biofilms
NASA Astrophysics Data System (ADS)
Espeso, D. R.; Carpio, A.; Einarsson, B.
2015-02-01
Biofilms are antibiotic-resistant bacterial aggregates that grow on moist surfaces and can trigger hospital-acquired infections. They provide a classical example in biology where the dynamics of cellular communities may be observed and studied. Gene expression regulates cell division and differentiation, which affect the biofilm architecture. Mechanical and chemical processes shape the resulting structure. We gain insight into the interplay between cellular and mechanical processes during biofilm development on air-agar interfaces by means of a hybrid model. Cellular behavior is governed by stochastic rules informed by a cascade of concentration fields for nutrients, waste, and autoinducers. Cellular differentiation and death alter the structure and the mechanical properties of the biofilm, which is deformed according to Föppl-Von Kármán equations informed by cellular processes and the interaction with the substratum. Stiffness gradients due to growth and swelling produce wrinkle branching. We are able to reproduce wrinkled structures often formed by biofilms on air-agar interfaces, as well as spatial distributions of differentiated cells commonly observed with B. subtilis.
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[In vitro activity of matrine against Candida albicans biofilms].
Wu, Lan; Zhou, Zeng-tong; Zhou, Yong-mei; Wang, Hai-yan; Shi, Lin-jun
2009-08-01
To establish a model of Candida albicans biofilms and to examine the effect of matrine on C.albicans biofilms and ultrastructure. C. albicans collection strain ATCC76615 was obtained and propagated. Biofilms were formed in 96-well microtiter plates. Antifungal susceptibility testing of C. albicans biofilms were assessed with the tetrazolium salt (XTT) reduction assay. Confocal laser scanning microscopy (CLSM) and dead/live fluorescent staining technique were combined to detect the effects of Matrine on preformed C. albican biofilms' composition and ultrastructure. Matrine was active against different growth stages (early,middle,mature) of biofilms; The bioactivity and drug-resistance of C. albican biofilm increased with culturing time. CLSM showed that C. albicans biofilms were inhibited and growth were predominantly composed of yeast cells and pseudohyphae. This study demonstrates that Matrine has potent activity against C.albicans biofilms in vitro and potential therapeutic implication for biofilm-associated candidal infections.
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Effect of Antimicrobial and Physical Treatments on Growth of Multispecies Staphylococcal Biofilms
Payne, David E.; Ma, Tianhui Maria; VanEpps, J. Scott; Boles, Blaise R.; Younger, John G.
2017-01-01
ABSTRACT The prevalence and structure of Staphylococcus aureus and Staphylococcus epidermidis within multispecies biofilms were found to depend sensitively on physical environment and antibiotic dosage. Although these species commonly infect similar sites, such as orthopedic implants, little is known about their behavior in multispecies communities, particularly in response to treatment. This research establishes that S. aureus is much more prevalent than S. epidermidis when simultaneously seeded and grown under unstressed conditions (pH 7, 37°C) in both laboratory and clinical strains. In multispecies communities, S. epidermidis is capable of growing a more confluent biofilm when the addition of S. aureus is delayed 4 to 6 h during 18 h of growth. Different vancomycin dosages generate various behaviors: S. epidermidis is more prevalent at a dose of 1.0 μg/ml vancomycin, but reduced growth of both species occurs at 1.9 μg/ml vancomycin. This variability is consistent with the different MICs of S. aureus and S. epidermidis. Growth at higher temperature (45°C) results in an environment where S. aureus forms porous biofilms. This porosity allows S. epidermidis to colonize more of the surface, resulting in detectable S. epidermidis biomass. Variations in pH result in increased prevalence of S. epidermidis at low pH (pH 5 and 6), while S. aureus remains dominant at high pH (pH 8 and 9). This work establishes the structural variability of multispecies staphylococcal biofilms as they undergo physical and antimicrobial treatments. It provides a basis for understanding the structure of these communities at infection sites and how treatments disrupt their multispecies behaviors. IMPORTANCE Staphylococcus aureus and Staphylococcus epidermidis are two species of bacteria that are commonly responsible for biofilm infections on medical devices. Biofilms are structured communities of bacteria surrounded by polysaccharides, proteins, and DNA; bacteria are more resistant to
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Effect of Antimicrobial and Physical Treatments on Growth of Multispecies Staphylococcal Biofilms.
Stewart, Elizabeth J; Payne, David E; Ma, Tianhui Maria; VanEpps, J Scott; Boles, Blaise R; Younger, John G; Solomon, Michael J
2017-06-15
The prevalence and structure of Staphylococcus aureus and Staphylococcus epidermidis within multispecies biofilms were found to depend sensitively on physical environment and antibiotic dosage. Although these species commonly infect similar sites, such as orthopedic implants, little is known about their behavior in multispecies communities, particularly in response to treatment. This research establishes that S. aureus is much more prevalent than S. epidermidis when simultaneously seeded and grown under unstressed conditions (pH 7, 37°C) in both laboratory and clinical strains. In multispecies communities, S. epidermidis is capable of growing a more confluent biofilm when the addition of S. aureus is delayed 4 to 6 h during 18 h of growth. Different vancomycin dosages generate various behaviors: S. epidermidis is more prevalent at a dose of 1.0 μg/ml vancomycin, but reduced growth of both species occurs at 1.9 μg/ml vancomycin. This variability is consistent with the different MICs of S. aureus and S. epidermidis Growth at higher temperature (45°C) results in an environment where S. aureus forms porous biofilms. This porosity allows S. epidermidis to colonize more of the surface, resulting in detectable S. epidermidis biomass. Variations in pH result in increased prevalence of S. epidermidis at low pH (pH 5 and 6), while S. aureus remains dominant at high pH (pH 8 and 9). This work establishes the structural variability of multispecies staphylococcal biofilms as they undergo physical and antimicrobial treatments. It provides a basis for understanding the structure of these communities at infection sites and how treatments disrupt their multispecies behaviors. IMPORTANCE Staphylococcus aureus and Staphylococcus epidermidis are two species of bacteria that are commonly responsible for biofilm infections on medical devices. Biofilms are structured communities of bacteria surrounded by polysaccharides, proteins, and DNA; bacteria are more resistant to
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[On Biofilms of Streptomycetes. II. Use in Biotechnology].
Vinogradoya, A; Bulgakova, V G; Polin, A N; Kozhevin, P A
2015-01-01
Streptomycetes or mycelial microorganisms are able to form biofilms under the natural, industrial and clinical conditions. The controlled use of biofilms in various industrial processes is much more efficient vs. the cultivation of plankton suspended cells. Optimization of biotechnological processes with the use of streptomycete biofilms is advisable in production of lactic acid and detoxication of the liquor in pyrolysis of plant biomass. Streptomycete biofilms are used in water purification systems. It is recommended to use biofilms for detoxication of wastes and bioremediation of soils contaminated with hard metals. The use of biofilms of streptomycetes producing biologically active substances is of special interest. High yields of.antibiotics and actinomycin D in particular was observed with. cultivation of antibioc-producing streptomycetes as biofilms in bioreactors of unique design.
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Gallarato, L A; Mulko, L E; Dardanelli, M S; Barbero, C A; Acevedo, D F; Yslas, E I
2017-02-01
Biofilm Formation is a survival strategy for microorganisms to adapt to their environment. Microbial cells in biofilm become tolerant and resistant to antibiotics and immune responses, increasing the difficulties for the clinical treatment of microbial infections. The surface chemistry and the micro/nano-topography of solid interfaces play a major role in mediating microorganism activity and adhesion. The effect of the surface chemical composition and topography on the adhesion and viability of Pseudomonas aeruginosa was studied. Polymeric (polyethylene terephthalate) surfaces were covered with a conducting polymer (polyaniline, PANI) film by in-situ polymerization and microstructured by Direct Laser Interference Patterning (DLIP). The viability of Pseudomonas aeruginosa on the different surfaces was investigated. The physicochemical properties of the surfaces were characterized by water contact angle measurements, scanning electron microscopy and atomic force microscopy. Bacterial biofilms were imaged by atomic force and scanning electron microscopies. The bacterial viability decreased on PANI compared with the substrate (polyethylene terephthalate) and it decreased even more upon micro-structuring the PANI films. In addition, the biofilm reduction could be improved using polymers with different chemical composition and/or the same polymer with different topographies. Both methods presented diminish the bacterial attachment and biofilm formation. These findings present a high impact related to materials for biomedical engineer applications regarding medical devices, as prostheses or catheters. Copyright © 2016 Elsevier B.V. All rights reserved.
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Habouzit, Frédéric; Hamelin, Jérôme; Santa-Catalina, Gaëlle; Steyer, Jean-P; Bernet, Nicolas
2014-01-01
To evaluate the impact of the nature of the support material on its colonization by a methanogenic consortium, four substrata made of different materials: polyvinyl chloride, 2 polyethylene and polypropylene were tested during the start-up of lab-scale fixed-film reactors. The reactor performances were evaluated and compared together with the analysis of the biofilms. Biofilm growth was quantified and the structure of bacterial and archaeal communities were characterized by molecular fingerprinting profiles (capillary electrophoresis-single strand conformation polymorphism). The composition of the inoculum was shown to have a major impact on the bacterial composition of the biofilm, whatever the nature of the support material or the organic loading rate applied to the reactors during the start-up period. In contrast, the biofilm archaeal populations were independent of the inoculum used but highly dependent on the support material. Supports favouring Archaea colonization, the limiting factor in the overall process, should be preferred. PMID:24612643
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Mori, Miho; Gomi, Mitsuhiro; Matsumune, Norihiko; Niizeki, Kazuma; Sakagami, Yoshikazu
2013-01-01
To evaluate the sanitary conditions of toilets, the bacterial counts of the toilet bowl biofilms in 5 Kansai area and 11 Kansai and Kanto area homes in Japan were measured in winter and summer seasons, respectively. Isolates (128 strains) were identified by analyzing 16S ribosomal RNA sequences. The number of colonies and bacterial species from biofilms sampled in winter tended to be higher and lower, respectively, than those in summer. Moreover, the composition of bacterial communities in summer and winter samples differed considerably. In summer samples, biofilms in Kansai and Kanto areas were dominated by Blastomonas sp. and Mycobacterium sp., respectively. Methylobacterium sp. was detected in all toilet bowl biofilms except for one sample. Methylobacterium sp. constituted the major presence in biofilms along with Brevundimonas sp., Sphingomonas sp., and/or Pseudomonas sp. The composition ratio of the sum of their genera was 88.0 from 42.9% of the total bacterial flora. The biofilm formation abilities of 128 isolates were investigated, and results suggested that Methylobacterium sp. and Sphingomonas sp. were involved in biofilm formation in toilet bowls. The biofilm formation of a mixed bacteria system that included bacteria with the highest biofilm-forming ability in a winter sample was greater than mixture without such bacteria. This result suggests that isolates possessing a high biofilm-forming activity are involved in the biofilm formation in the actual toilet bowl. A bactericidal test against 25 strains indicated that the bactericidal activities of didecyldimethylammonium chloride (DDAC) tended to be higher than those of polyhexamethylene biguanide (PHMB) and N-benzyl-N,N-dimethyldodecylammonium chloride (ADBAC). In particular, DDAC showed high bactericidal activity against approximately 90% of tested strains under the 5 h treatment.
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Rocco, Christopher J.; Davey, Mary Ellen; Bakaletz, Lauren O.; Goodman, Steven D.
2016-01-01
SUMMARY Bacteria that persist in the oral cavity exist within complex biofilm communities. A hallmark of biofilms is the presence of an extracellular polymeric substance (EPS), which consists of polysaccharides, extracellular DNA (eDNA), and proteins, including the DNABII family of proteins. The removal of DNABII proteins from a biofilm results in the loss of structural integrity of the eDNA and the collapse of the biofilm structure. We examined the role of DNABII proteins in the biofilm structure of the periodontal pathogen Porphyromonas gingivalis and the oral commensal Streptococcus gordonii. Co-aggregation with oral streptococci is thought to facilitate the establishment of P. gingivalis within the biofilm community. We demonstrate that DNABII proteins are present in the EPS of both S. gordonii and P. gingivalis biofilms, and that these biofilms can be disrupted through the addition of antisera derived against their respective DNABII proteins. We provide evidence that both eDNA and DNABII proteins are limiting in S. gordonii but not in P. gingivalis biofilms. In addition, these proteins are capable of complementing one another functionally. We also found that while antisera derived against most DNABII proteins are capable of binding a wide variety of DNABII proteins, the P. gingivalis DNABII proteins are antigenically distinct. The presence of DNABII proteins in the EPS of these biofilms and the antigenic uniqueness of the P. gingivalis proteins provide an opportunity to develop therapies that are targeted to remove P. gingivalis and biofilms that contain P. gingivalis from the oral cavity. PMID:26988714
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Efficacy of ferulic acid encapsulated chitosan nanoparticles against Candida albicans biofilm.
Panwar, Richa; Pemmaraju, Suma C; Sharma, Asvene K; Pruthi, Vikas
2016-06-01
Candida albicans, an opportunistic fungal pathogen is a major causative agent of superficial to systemic life-threating biofilm infections on indwelling medical devices. These biofilms acts as double edge swords owing to their resistance towards antibiotics and immunological barriers. To overcome this threat ferulic acid encapsulated chitosan nanoparticles (FA-CSNPs) were formulated to assess its efficacy as an antibiofilm agent against C. albicans. These FA-CSNPs were synthesized using ionotropic gelation method and observed through field emission scanning electron microscopy (FESEM) and fluorescent microscopy. Assessment of successful encapsulation and stability of ferulic acid into chitosan nanoparticles was made using Fourier transform infrared spectrum (FTIR), (1)H NMR and thermal analyses. Synthesized FA-CSNPs, were found to be cytocompatible, when tested using Human Embryonic Kidney (HEK-293) cell lines. XTT assay revealed that FA-CSNPs reduced the cell metabolic activity of C. albicans upto 22.5% as compared to native ferulic acid (63%) and unloaded CSNPs (88%) after 24 h incubation. Disruption of C. albicans biofilm architecture was visualized by FESEM. Results highlighted the potential of FA-CSNPs to be used as an effective alternative to the conventional antifungal therapeutics. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Sexual Biofilm Formation in Candida tropicalis Opaque Cells
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
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Current and future trends for biofilm reactors for fermentation processes.
Ercan, Duygu; Demirci, Ali
2015-03-01
Biofilms in the environment can both cause detrimental and beneficial effects. However, their use in bioreactors provides many advantages including lesser tendencies to develop membrane fouling and lower required capital costs, their higher biomass density and operation stability, contribution to resistance of microorganisms, etc. Biofilm formation occurs naturally by the attachment of microbial cells to the support without use of any chemicals agent in biofilm reactors. Biofilm reactors have been studied and commercially used for waste water treatment and bench and pilot-scale production of value-added products in the past decades. It is important to understand the fundamentals of biofilm formation, physical and chemical properties of a biofilm matrix to run the biofilm reactor at optimum conditions. This review includes the principles of biofilm formation; properties of a biofilm matrix and their roles in the biofilm formation; factors that improve the biofilm formation, such as support materials; advantages and disadvantages of biofilm reactors; and industrial applications of biofilm reactors.
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Pérez-Rodríguez, Gael; Glez-Peña, Daniel; Azevedo, Nuno F; Pereira, Maria Olívia; Fdez-Riverola, Florentino; Lourenço, Anália
2015-03-01
Biofilms are receiving increasing attention from the biomedical community. Biofilm-like growth within human body is considered one of the key microbial strategies to augment resistance and persistence during infectious processes. The Biofilms Experiment Workbench is a novel software workbench for the operation and analysis of biofilms experimental data. The goal is to promote the interchange and comparison of data among laboratories, providing systematic, harmonised and large-scale data computation. The workbench was developed with AIBench, an open-source Java desktop application framework for scientific software development in the domain of translational biomedicine. Implementation favours free and open-source third-parties, such as the R statistical package, and reaches for the Web services of the BiofOmics database to enable public experiment deposition. First, we summarise the novel, free, open, XML-based interchange format for encoding biofilms experimental data. Then, we describe the execution of common scenarios of operation with the new workbench, such as the creation of new experiments, the importation of data from Excel spreadsheets, the computation of analytical results, the on-demand and highly customised construction of Web publishable reports, and the comparison of results between laboratories. A considerable and varied amount of biofilms data is being generated, and there is a critical need to develop bioinformatics tools that expedite the interchange and comparison of microbiological and clinical results among laboratories. We propose a simple, open-source software infrastructure which is effective, extensible and easy to understand. The workbench is freely available for non-commercial use at http://sing.ei.uvigo.es/bew under LGPL license. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
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Electroactive Biofilms: Current Status and Future Research Needs
DOE Office of Scientific and Technical Information (OSTI.GOV)
Borole, Abhijeet P; Reguera, Gemma; Ringeisen, Bradley
2011-01-01
Electroactive biofilms generated by electrochemically active microorganisms have many potential applications in bioenergy and chemicals production. This review assesses the effects of microbiological and process parameters on enrichment of such biofilms as well as critically evaluates the current knowledge of the mechanisms of extracellular electron transfer in BES systems. First we discuss the role of biofilm forming microorganisms vs. planktonic microorganisms. Physical, chemical and electrochemical parameters which dictate the enrichment and subsequent performance of the biofilms are discussed. Potential dependent biological parameters including biofilm growth rate, specific electron transfer rate and others and their relationship to BES system performance ismore » assessed. A review of the mechanisms of electron transfer in BES systems is included followed by a discussion of biofilm and its exopolymeric components and their electrical conductivity. A discussion of the electroactive biofilms in biocathodes is also included. Finally, we identify the research needs for further development of the electroactive biofilms to enable commercial applications.« less
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Biofilms in Endodontics-Current Status and Future Directions.
Neelakantan, Prasanna; Romero, Monica; Vera, Jorge; Daood, Umer; Khan, Asad U; Yan, Aixin; Cheung, Gary Shun Pan
2017-08-11
Microbiota are found in highly organized and complex entities, known as biofilms, the characteristics of which are fundamentally different from microbes in planktonic suspensions. Root canal infections are biofilm mediated. The complexity and variability of the root canal system, together with the multi-species nature of biofilms, make disinfection of this system extremely challenging. Microbial persistence appears to be the most important factor for failure of root canal treatment and this could further have an impact on pain and quality of life. Biofilm removal is accomplished by a chemo-mechanical process, using specific instruments and disinfecting chemicals in the form of irrigants and/or intracanal medicaments. Endodontic research has focused on the characterization of root canal biofilms and the clinical methods to disrupt the biofilms in addition to achieving microbial killing. In this narrative review, we discuss the role of microbial biofilms in endodontics and review the literature on the role of root canal disinfectants and disinfectant-activating methods on biofilm removal.
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Biofilms in Endodontics—Current Status and Future Directions
Neelakantan, Prasanna; Romero, Monica; Vera, Jorge; Daood, Umer; Khan, Asad U.; Yan, Aixin; Cheung, Gary Shun Pan
2017-01-01
Microbiota are found in highly organized and complex entities, known as biofilms, the characteristics of which are fundamentally different from microbes in planktonic suspensions. Root canal infections are biofilm mediated. The complexity and variability of the root canal system, together with the multi-species nature of biofilms, make disinfection of this system extremely challenging. Microbial persistence appears to be the most important factor for failure of root canal treatment and this could further have an impact on pain and quality of life. Biofilm removal is accomplished by a chemo-mechanical process, using specific instruments and disinfecting chemicals in the form of irrigants and/or intracanal medicaments. Endodontic research has focused on the characterization of root canal biofilms and the clinical methods to disrupt the biofilms in addition to achieving microbial killing. In this narrative review, we discuss the role of microbial biofilms in endodontics and review the literature on the role of root canal disinfectants and disinfectant-activating methods on biofilm removal. PMID:28800075
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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 2.73±0.06 and 2.68±0.06, respectively, while in the maturation stage, Df=2.57±0.08. 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.
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Hammond, Adrienne A; Miller, Kyle G; Kruczek, Cassandra J; Dertien, Janet; Colmer-Hamood, Jane A; Griswold, John A; Horswill, Alexander R; Hamood, Abdul N
2011-03-01
Topical treatment of burn wounds is essential as reduced blood supply in the burned tissues restricts the effect of systemic antibiotics. On the burn surface, microorganisms exist within a complex structure termed a biofilm, which enhances bacterial resistance to antimicrobial agents significantly. Since bacteria differ in their ability to develop biofilms, the susceptibility of these biofilms to topically applied antibiotics varies, making it essential to identify which topical antibiotics efficiently disrupt or prevent biofilms produced by these pathogens. Yet, a simple in vitro assay to compare the susceptibility of biofilms produced by burn wound isolates to different topical antibiotics has not been reported. Biofilms were developed by inoculating cellulose disks on agar plates with burn wound isolates and incubating for 24h. The biofilms were then covered for 24h with untreated gauze or gauze coated with antibiotic ointment and remaining microorganisms were quantified and visualized microscopically. Mupirocin and triple antibiotic ointments significantly reduced biofilms produced by the Staphylococcus aureus and Pseudomonas aeruginosa burn wound isolates tested, as did gentamicin ointment, with the exception of one P. aeruginosa clinical isolate. The described assay is a practical and reproducible approach to identify topical antibiotics most effective in eliminating biofilms produced by burn wound isolates. Copyright © 2010 Elsevier Ltd and ISBI. All rights reserved.
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Janjaroen, Dao; Ling, Fangqiong; Monroy, Guillermo; Derlon, Nicolas; Mogenroth, Eberhard; Boppart, Stephen A.; Liu, Wen-Tso; Nguyen, Thanh H.
2013-01-01
Mechanisms of Escherichia coli attachment on biofilms grown on PVC coupons were investigated. Biofilms were grown in CDC reactors using groundwater as feed solution over a period up to 27 weeks. Biofilm physical structure was characterized at the micro- and meso-scales using Scanning Electron Microscopy (SEM) and Optical Coherence Tomography (OCT), respectively. Microbial community diversity was analyzed with Terminal Restricted Fragment Length Polymorphism (T-RFLP). Both physical structure and microbial community diversity of the biofilms were shown to be changing from 2 weeks to 14 weeks, and became relatively stable after 16 weeks. A parallel plate flow chamber coupled with an inverted fluorescent microscope was also used to monitor the attachment of fluorescent microspheres and E. coli on clean PVC surfaces and biofilms grown on PVC surfaces for different ages. Two mechanisms of E. coli attachment were identified. The adhesion rate coefficients (kd) of E. coli on nascent PVC surfaces and 2-week biofilms increased with ionic strength. However, after biofilms grew for 8 weeks, the adhesion was found to be independent of solution chemistry. Instead, a positive correlation between kd and biofilm roughness as determined by OCT was obtained, indicating that the physical structure of biofilms could play an important role in facilitating the adhesion of E. coli cells. PMID:23497979
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Oral Biofilm Architecture on Natural Teeth
Zijnge, Vincent; van Leeuwen, M. Barbara M.; Degener, John E.; Abbas, Frank; Thurnheer, Thomas; Gmür, Rudolf; M. Harmsen, Hermie J.
2010-01-01
Periodontitis and caries are infectious diseases of the oral cavity in which oral biofilms play a causative role. Moreover, oral biofilms are widely studied as model systems for bacterial adhesion, biofilm development, and biofilm resistance to antibiotics, due to their widespread presence and accessibility. Despite descriptions of initial plaque formation on the tooth surface, studies on mature plaque and plaque structure below the gum are limited to landmark studies from the 1970s, without appreciating the breadth of microbial diversity in the plaque. We used fluorescent in situ hybridization to localize in vivo the most abundant species from different phyla and species associated with periodontitis on seven embedded teeth obtained from four different subjects. The data showed convincingly the dominance of Actinomyces sp., Tannerella forsythia, Fusobacterium nucleatum, Spirochaetes, and Synergistetes in subgingival plaque. The latter proved to be new with a possibly important role in host-pathogen interaction due to its localization in close proximity to immune cells. The present study identified for the first time in vivo that Lactobacillus sp. are the central cells of bacterial aggregates in subgingival plaque, and that Streptococcus sp. and the yeast Candida albicans form corncob structures in supragingival plaque. Finally, periodontal pathogens colonize already formed biofilms and form microcolonies therein. These in vivo observations on oral biofilms provide a clear vision on biofilm architecture and the spatial distribution of predominant species. PMID:20195365
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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…
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An improved protocol for harvesting Bacillus subtilis colony biofilms.
Fuchs, Felix Matthias; Driks, Adam; Setlow, Peter; Moeller, Ralf
2017-03-01
Bacterial biofilms cause severe problems in medicine and industry due to the high resistance to disinfectants and environmental stress of organisms within biofilms. Addressing challenges caused by biofilms requires full understanding of the underlying mechanisms for bacterial resistance and survival in biofilms. However, such work is hampered by a relative lack of systems for biofilm cultivation that are practical and reproducible. To address this problem, we developed a readily applicable method to culture Bacillus subtilis biofilms on a membrane filter. The method results in biofilms with highly reproducible characteristics, and which can be readily analyzed by a variety of methods with little further manipulation. This biofilm preparation method simplifies routine generation of B. subtilis biofilms for molecular and cellular analysis, and could be applicable to other microbial systems. Copyright © 2017 Elsevier B.V. All rights reserved.
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Efficacy of a surfactant-based wound dressing on biofilm control.
Percival, Steven L; Mayer, Dieter; Salisbury, Anne-Marie
2017-09-01
The aim of this study was to evaluate the efficacy of both a nonantimicrobial and antimicrobial (1% silver sulfadiazine-SSD) surfactant-based wound dressing in the control of Pseudomonas aeruginosa, Enterococcus sp, Staphylococcus epidermidis, Staphylococcus aureus, and methicillin-resistant S. aureus (MRSA) biofilms. Anti-biofilm efficacy was evaluated in numerous adapted American Standards for Testing and Materials (ASTM) standard biofilm models and other bespoke biofilm models. The ASTM standard models employed included the Minimum biofilm eradication concentration (MBEC) biofilm model (ASTM E2799) and the Centers for Disease Control (CDC) biofilm reactor model (ASTM 2871). Such bespoke biofilm models included the filter biofilm model and the chamberslide biofilm model. Results showed complete kill of microorganisms within a biofilm using the antimicrobial surfactant-based wound dressing. Interestingly, the nonantimicrobial surfactant-based dressing could disrupt existing biofilms by causing biofilm detachment. Prior to biofilm detachment, we demonstrated, using confocal laser scanning microscopy (CLSM), the dispersive effect of the nonantimicrobial surfactant-based wound dressing on the biofilm within 10 minutes of treatment. Furthermore, the non-antimicrobial surfactant-based wound dressing caused an increase in microbial flocculation/aggregation, important for microbial concentration. In conclusion, this nonantimicrobial surfactant-based wound dressing leads to the effective detachment and dispersion of in vitro biofilms. The use of surfactant-based wound dressings in a clinical setting may help to disrupt existing biofilm from wound tissue and may increase the action of antimicrobial treatment. © 2017 by the Wound Healing Society.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
James, Garth A.; Ge Zhao, Alice; Usui, Marcia
Polymicrobial biofilms have been implicated in delayed wound healing, although the mechanisms by which biofilms impair wound healing are poorly understood. Many species of bacteria produce exotoxins and exoenzymes that may inhibit healing. In addition, oxygen consumption by biofilms may impede wound healing. In this study, we used oxygen microsensors to measure oxygen transects through in vitro-cultured biofilms, biofilms formed in vivo in a diabetic (db/db) mouse model, and ex vivo human chronic wound specimens. The results show that oxygen levels within both euthanized and live mouse wounds had steep gradients that reached minima ranging from 19 to 61% oxygenmore » partial pressure, compared to atmospheric oxygen levels. The oxygen gradients in the mouse wounds were similar to those observed for clinical isolates cultured in vitro and for human ex vivo scabs. No oxygen gradients were observed for heat-killed scabs, suggesting that active metabolism by the viable bacteria contributed to the reduced oxygen partial pressure of the wounds. To characterize the metabolic activities of the bacteria in the mouse wounds, we performed transcriptomics analyses of Pseudomonas aeruginosa biofilms associated with the db/db mice wounds using Affymetrix microarrays. The results demonstrated that the bacteria expressed genes for metabolic activities associated with cell growth. Interestingly, the transcriptome results indicated that the bacteria within the wounds also experienced oxygen-limitation stress. Among the bacterial genes that were expressed in vivo were genes associated with the Anr-mediated hypoxia-stress response. Other bacterial stress response genes highly expressed in vivo were genes associated with stationary-phase growth, osmotic stress, and RpoH-mediated heat shock stress. Overall, the results support the hypothesis that the metabolic activities of bacteria in biofilms act as oxygen sinks in chronic wounds and that the depletion of oxygen contributes to the
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Giongo, Janice Luehring; de Almeida Vaucher, Rodrigo; Fausto, Viviane Pedroso; Quatrin, Priscilla Maciel; Lopes, Leonardo Quintana Soares; Santos, Roberto Christ Vianna; Gündel, André; Gomes, Patrícia; Steppe, Martin
2016-11-01
Infections due to microbial biofilm formation on the surface of catheters and other medical devices are constantly reported as a major cause of morbidity and mortality in patients admitted to hospitals. Furthermore, sessile cells are more resistant to phagocytosis and most antimicrobial, which complicates the treatment of such infections. Researches aimed at new antimicrobial originating mainly from plants have increased in recent years and the development of new strategies for their release is critical in combating the formation of biofilms. Geranium oil (GO) has proven antimicrobial activity. Because of this, the aim of this study was to develop nanoemulsions containing this oil (NEG) and evaluate its activity after the biofilm formation of Candida albicans, Candida tropicalis, Candida glabrata, and Candida krusei in hospital medical supplies. For quantification of the biofilm, crystal violet, total protein, and ATP-bioluminescence assays were used. The results revealed that GO and NEG showed lower MIC for C. albicans and C. tropicalis. The biofilms formed by different species of Candida on the surfaces of polyethylene and polyurethane were quantified. GO and NEG significantly inhibited the formation of biofilms in all species tested on the surfaces of polyethylene. However, NEG antibiofilm has had better activity than GO for C. albicans, C. tropicalis and C. glabrata, according to the surface potential analysis by atomic force microscopy (AFM). The analysis of the biofilm formation on the polyethylene surface by ATP-bioluminescence and CFU showed similar results. In both methods the formation of biofilm in the catheter occurred in greater quantity for C. albicans and C. tropicalis. GO did not significantly inhibit the formation of biofilms only in C. krusei, although NEG significantly increased this activity GO in all species tested when compared to the control training biofilm. The following study shows that the development of NEG may become an effective
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Liao, Julie; Schurr, Michael J; Sauer, Karin
2013-08-01
A defining characteristic of biofilms is antibiotic tolerance that can be up to 1,000-fold greater than that of planktonic cells. In Pseudomonas aeruginosa, biofilm tolerance to antimicrobial agents requires the biofilm-specific MerR-type transcriptional regulator BrlR. However, the mechanism by which BrlR mediates biofilm tolerance has not been elucidated. Genome-wide transcriptional profiling indicated that brlR was required for maximal expression of genes associated with antibiotic resistance, in particular those encoding the multidrug efflux pumps MexAB-OprM and MexEF-OprN. Chromatin immunoprecipitation (ChIP) analysis revealed a direct regulation of these genes by BrlR, with DNA binding assays confirming BrlR binding to the promoter regions of the mexAB-oprM and mexEF-oprN operons. Quantitative reverse transcriptase PCR (qRT-PCR) analysis further indicated BrlR to be an activator of mexAB-oprM and mexEF-oprN gene expression. Moreover, immunoblot analysis confirmed increased MexA abundance in cells overexpressing brlR. Inactivation of both efflux pumps rendered biofilms significantly more susceptible to five different classes of antibiotics by affecting MIC but not the recalcitrance of biofilms to killing by bactericidal agents. Overexpression of either efflux pump in a ΔbrlR strain partly restored tolerance of ΔbrlR biofilms to antibiotics. Expression of brlR in mutant biofilms lacking both efflux pumps partly restored antimicrobial tolerance of biofilms to wild-type levels. Our results indicate that BrlR acts as an activator of multidrug efflux pumps to confer tolerance to P. aeruginosa biofilms and to resist the action of antimicrobial agents.
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IMPACTS OF BIOFILM FORMATION ON CELLULOSE FERMENTATION
DOE Office of Scientific and Technical Information (OSTI.GOV)
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 developmentmore » 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
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Biofilm-specific extracellular matrix proteins of non-typeable Haemophilus influenzae
Wu, Siva; Baum, Marc M.; Kerwin, James; Guerrero-Given, Debbie; Webster, Simon; Schaudinn, Christoph; VanderVelde, David; Webster, Paul
2014-01-01
Non-typeable Haemophilus influenzae (NTHi), a human respiratory tract pathogen can form colony biofilms in vitro. Bacterial cells and the amorphous extracellular matrix (ECM) constituting the biofilm can be separated using sonication. The ECM from 24 hr and 96 hr NTHi biofilms contained polysaccharides and proteinaceous components as detected by NMR and FTIR spectroscopy. More conventional chemical assays on the biofilm ECM confirmed the presence of these components and also DNA. Proteomics revealed eighteen proteins present in biofilm ECM that were not detected in planktonic bacteria. One ECM protein was unique to 24 hr biofilms, two were found only in 96 hr biofilms, and fifteen were present in the ECM of both 24 hr and 96 hr NTHi biofilms. All proteins identified were either associated with bacterial membranes or were cytoplasmic proteins. Immunocytochemistry showed two of the identified proteins, a DNA-directed RNA polymerase and the outer membrane protein OMP P2, associated with bacteria and biofilm ECM. Identification of biofilm-specific proteins present in immature biofilms is an important step in understanding the in vitro process of NTHi biofilm formation. The presence of a cytoplasmic protein and a membrane protein in the biofilm ECM of immature NTHi biofilms suggests that bacterial cell lysis may be a feature of early biofilm formation. PMID:24942343
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Sun, Lingmei; Liao, Kai; Wang, Dayong
2015-01-01
Background The first step in infection by Candida albicans is adhesion to host cells or implanted medical devices and this followed by hyphal growth and biofilm formation. Yeast-to-hyphal transition has long been identified as a key factor in fungal virulence. Following biofilm formation, C. albicans is usually less sensitive or insensitive to antifungals. Therefore, development of new antifungals with inhibitory action on adhesion, yeast-hyphal transition and biofilm formation by C. albicans is very necessary. Methods The effects of magnolol and honokiol on hypha growth were investigated using different induction media. Their inhibitory effects were determined using the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5- carboxanilide assay, and biofilm thickness and viability were observed by a confocal scanning laser microscope. Mammalian cells were used in adhesion assays. Genes related to hyphae development and cell adhesions were analyzed by real-time reverse transcription-polymerase chain reaction. The exogenous cyclic adenosine monophosphate was used to determine the mechanisms of action of magnolol and honokiol. Caenorhabditis elegans was used as an in vivo model to estimate the antifungal activities of magnolol and honokiol. Results and conclusions Magnolol and honokiol inhibited adhesion, the transition from yeast to hypha, and biofilm formation by C. albicans through the Ras1-cAMP-Efg1 pathway. Moreover, magnolol and honokiol prolonged the survival of nematodes infected by C. albicans. Magnolol and honokiol have potential inhibitory effects against biofilm formation by C. albicans. General Significance This study provides useful information towards the development of new strategies to reduce the incidence of C. albicans biofilm-associated infection. PMID:25710475
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Rocco, C J; Davey, M E; Bakaletz, L O; Goodman, S D
2017-04-01
Bacteria that persist in the oral cavity exist within complex biofilm communities. A hallmark of biofilms is the presence of an extracellular polymeric substance (EPS), which consists of polysaccharides, extracellular DNA (eDNA), and proteins, including the DNABII family of proteins. The removal of DNABII proteins from a biofilm results in the loss of structural integrity of the eDNA and the collapse of the biofilm structure. We examined the role of DNABII proteins in the biofilm structure of the periodontal pathogen Porphyromonas gingivalis and the oral commensal Streptococcus gordonii. Co-aggregation with oral streptococci is thought to facilitate the establishment of P. gingivalis within the biofilm community. We demonstrate that DNABII proteins are present in the EPS of both S. gordonii and P. gingivalis biofilms, and that these biofilms can be disrupted through the addition of antisera derived against their respective DNABII proteins. We provide evidence that both eDNA and DNABII proteins are limiting in S. gordonii but not in P. gingivalis biofilms. In addition, these proteins are capable of complementing one another functionally. We also found that whereas antisera derived against most DNABII proteins are capable of binding a wide variety of DNABII proteins, the P. gingivalis DNABII proteins are antigenically distinct. The presence of DNABII proteins in the EPS of these biofilms and the antigenic uniqueness of the P. gingivalis proteins provide an opportunity to develop therapies that are targeted to remove P. gingivalis and biofilms that contain P. gingivalis from the oral cavity. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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Antimicrobial Peptides in Biomedical Device Manufacturing.
Riool, Martijn; de Breij, Anna; Drijfhout, Jan W; Nibbering, Peter H; Zaat, Sebastian A J
2017-01-01
Over the past decades the use of medical devices, such as catheters, artificial heart valves, prosthetic joints, and other implants, has grown significantly. Despite continuous improvements in device design, surgical procedures, and wound care, biomaterial-associated infections (BAI) are still a major problem in modern medicine. Conventional antibiotic treatment often fails due to the low levels of antibiotic at the site of infection. The presence of biofilms on the biomaterial and/or the multidrug-resistant phenotype of the bacteria further impair the efficacy of antibiotic treatment. Removal of the biomaterial is then the last option to control the infection. Clearly, there is a pressing need for alternative strategies to prevent and treat BAI. Synthetic antimicrobial peptides (AMPs) are considered promising candidates as they are active against a broad spectrum of (antibiotic-resistant) planktonic bacteria and biofilms. Moreover, bacteria are less likely to develop resistance to these rapidly-acting peptides. In this review we highlight the four main strategies, three of which applying AMPs, in biomedical device manufacturing to prevent BAI. The first involves modification of the physicochemical characteristics of the surface of implants. Immobilization of AMPs on surfaces of medical devices with a variety of chemical techniques is essential in the second strategy. The main disadvantage of these two strategies relates to the limited antibacterial effect in the tissue surrounding the implant. This limitation is addressed by the third strategy that releases AMPs from a coating in a controlled fashion. Lastly, AMPs can be integrated in the design and manufacturing of additively manufactured/3D-printed implants, owing to the physicochemical characteristics of the implant material and the versatile manufacturing technologies compatible with antimicrobials incorporation. These novel technologies utilizing AMPs will contribute to development of novel and safe
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Antimicrobial Peptides in Biomedical Device Manufacturing
NASA Astrophysics Data System (ADS)
Riool, Martijn; de Breij, Anna; Drijfhout, Jan W.; Nibbering, Peter H.; Zaat, Sebastian A. J.
2017-08-01
Over the past decades the use of medical devices, such as catheters, artificial heart valves, prosthetic joints and other implants, has grown significantly. Despite continuous improvements in device design, surgical procedures and wound care, biomaterial-associated infections (BAI) are still a major problem in modern medicine. Conventional antibiotic treatment often fails due to the low levels of antibiotic at the site of infection. The presence of biofilms on the biomaterial and/or the multidrug-resistant phenotype of the bacteria further impair the efficacy of antibiotic treatment. Removal of the biomaterial is then the last option to control the infection. Clearly, there is a pressing need for alternative strategies to prevent and treat BAI. Synthetic antimicrobial peptides (AMPs) are considered promising candidates as they are active against a broad spectrum of (antibiotic-resistant) planktonic bacteria and biofilms. Moreover, bacteria are less likely to develop resistance to these rapidly-acting peptides. In this review we highlight the four main strategies, three of which applying AMPs, in biomedical device manufacturing to prevent BAI. The first involves modification of the physicochemical characteristics of the surface of implants. Immobilization of AMPs on surfaces of medical devices with a variety of chemical techniques is essential in the second strategy. The main disadvantage of these two strategies relates to the limited antibacterial effect in the tissue surrounding the implant. This limitation is addressed by the third strategy that releases AMPs from a coating in a controlled fashion. Lastly, AMPs can be integrated in the design and manufacturing of additively manufactured / 3D-printed implants, owing to the physicochemical characteristics of the implant material and the versatile manufacturing technologies compatible with antimicrobials incorporation. These novel technologies utilizing AMPs will contribute to development of novel and safe
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Removal of Burkholderia cepacia biofilms with oxidants
NASA Technical Reports Server (NTRS)
Koenig, D. W.; Mishra, S. K.; Pierson, D. L.
1995-01-01
Iodine is used to disinfect the water system aboard US space shuttles and is the anticipated biocide for the international space station. Water quality on spacecraft must be maintained at the highest possible levels for the safety of the crew. Furthermore, the treatment process used to maintain the quality of water on research must be robust and operate for long periods with minimal crew intervention. Biofilms are recalcitrant and pose a major threat with regard to chronic contamination of spacecraft water systems. We measured the effectiveness of oxidizing biocides on the removal and regrowth of Burkholderia (Pseudomonas) cepacia biofilms. B. cepacia, isolated from the water distribution system of the space shuttle Discovery, was grown in continuous culture to produce a bacterial contamination source for biofilm formation and removal studies. A 10(7) CFU ml-1 B. cepacia suspension, in distilled water, was used to form biofilms on 3000 micrometers2 glass surfaces. Rates of attachment were measured directly with image analysis and were found to be 7.8, 15.2, and 22.8 attachment events h-1 for flow rates of 20.7, 15.2, and 9.8 ml min-1, respectively. After 18 h of formation, the B. cepacia biofilms were challenged with oxidants (ozone, chlorine, and iodine) and the rates of biofilm removal determined by image analysis. Fifty percent of the biofilm material was removed in the first hour of continous treatment with 24 mg l-1 chlorine or 2 mg l-1 ozone. Iodine (48 mg l-1) did not remove any measurable cellular material after 6 h continuous contact. After this first removal of biofilms by the oxidants, the surface was allowed to refoul and was again treated with the biocide. Iodine was the only compound that was unable to remove cellular debris from either primary or secondary biofilms. Moreover, treating primary biofilms with iodine increased the rate of formation of secondary biofilms, from 4.4 to 5.8 attachment events h-1. All the oxidants tested inactivated the B
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Recolonization of laser-ablated bacterial biofilm.
Nandakumar, Kanavillil; Obika, Hideki; Utsumi, Akihiro; Toshihiko, Ooie; Yano, Tetsuo
2004-01-20
The recolonization of laser-ablated bacterial monoculture biofilm was studied in the laboratory by using a flow-cytometer system. The marine biofilm-forming bacterium Pseudoalteromonas carrageenovora was used to develop biofilms on titanium coupons. Upon exposure to a low-power pulsed irradiation from an Nd:YAG laser, the coupons with biofilm were significantly reduced both in terms of total viable count (TVC) and area cover. The energy density used for a pulse of 5 ns was 0.1 J/cm(2) and the durations of irradiation exposure were 5 and 10 min. When placed in a flow of dilute ZoBell marine broth medium (10%) the laser-destructed bacterial film in a flow-cytometer showed significant recovery over a period of time. The flow of medium was regulated at 3.2 ml/min. The increase in area cover and TVC, however, was significantly less than that observed for nonirradiated control (t-test, P< 0.05). The coupons were observed for biofilm area cover and TVC at different intervals (3, 6, and 9 h) after irradiation. While the biofilm in the control coupon at the end of 9 h of exposure showed 95.6 +/- 4.1% cover, the 5- and 10-min irradiated samples after 9 h showed 60.3 +/- 6.5 and 37.4 +/- 12.1% area cover, respectively. The reduced rate of recolonization compared to control was thought be due to the lethal and sublethal impacts of laser irradiation on bacteria. This observation thus provided data on the online recolonization speed of biofilm, which is important when considering pulsed laser irradiation as an ablating technique of biofilm formation and removal in natural systems. Copyright 2003 Wiley Periodicals, Inc.
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Biofilm monitoring using complex permittivity.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Altman, Susan Jeanne; McGrath, Lucas K.; Dolan, Patricia L.
2008-10-01
There is strong interest in the detection and monitoring of bio-fouling. Bio-fouling problems are common in numerous water treatments systems, medical and dental apparatus and food processing equipment. Current bio-fouling control protocols are time consuming and costly. New early detection techniques to monitor bio-forming contaminates are means to enhanced efficiency. Understanding the unique dielectric properties of biofilm development, colony forming bacteria and nutrient background will provide a basis to the effectiveness of controlling or preventing biofilm growth. Dielectric spectroscopy measurements provide values of complex permittivity, {var_epsilon}*, of biofilm formation by applying a weak alternating electric field at various frequencies. Themore » dielectric characteristic of the biofilm, {var_epsilon}{prime}, is the real component of {var_epsilon}* and measures the biofilm's unique ability to store energy. Graphically observed dependencies of {var_epsilon}{prime} to frequency indicate dielectric relaxation or dielectric dispersion behaviors that mark the particular stage of progression during the development of biofilms. In contrast, any frequency dependency of the imaginary component, {var_epsilon}{double_prime} the loss factor, is expressed as dielectric losses from the biofilm due to dipole relaxation. The tangent angle of these two component vectors is the ratio of the imaginary component to the real component, {var_epsilon}{double_prime}/{var_epsilon}{prime} and is referred to as the loss angle tangent (tan {delta}) or dielectric loss. Changes in tan {delta} are characteristic of changes in dielectric losses during various developmental stages of the films. Permittivity scans in the above figure are of biofilm growth from P. Fluorescens (10e7 CFU's at the start). Three trends are apparent from these scans, the first being a small drop in the imaginary permittivity over a 7 hours period, best seen in the Cole-Cole plot (a). The second trend is
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EPS forces in Bacillus subtilis biofilms
NASA Astrophysics Data System (ADS)
Zhang, Wenbo; Angelini, Thomas; Tsai, Shih-Ming; Nixon, Ryan
2014-03-01
Bacteria have evolved to congregate in complex communities known as biofilms. The structure that holds a biofilm together is a matrix called extracellular polymeric substance (EPS). It has been observed in previous studies that EPS up-regulation occurs when the nutrient levels fall below a threshold concentration; this increase in EPS concentration produces an osmotic pressure that forces the colony to spread outward. This osmotic pressure may drive nutrient uptake, but the stresses generated by the EPS matrix has never been measured. Here we present measurements of the forces exerted by a biofilm on its supporting substrate and on its fluid nutrients. In our experiments, we use a technique analogous to traction force microscopy to measure strain in agar nutrient substrates imposed by Bacillus subtilis biofilms. By running additional test to measure the permeability and elastic modulus of the agar, we can estimate the pressure generated by the biofilm.
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Investigations into Monochloramine Biofilm Penetration
Biofilm in drinking water systems is undesirable. Free chlorine and monochloramine are commonly used as secondary drinking water disinfectants, but monochloramine is perceived to penetrate biofilm better than free chlorine. However, this hypothesis remains unconfirmed by direct b...
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Candida Biofilms: Threats, Challenges, and Promising Strategies.
Cavalheiro, Mafalda; Teixeira, Miguel Cacho
2018-01-01
Candida species are fungal pathogens known for their ability to cause superficial and systemic infections in the human host. These pathogens are able to persist inside the host due to the development of pathogenicity and multidrug resistance traits, often leading to the failure of therapeutic strategies. One specific feature of Candida species pathogenicity is their ability to form biofilms, which protects them from external factors such as host immune system defenses and antifungal drugs. This review focuses on the current threats and challenges when dealing with biofilms formed by Candida albicans, Candida glabrata, Candida tropicalis , and Candida parapsilosis , highlighting the differences between the four species. Biofilm characteristics depend on the ability of each species to produce extracellular polymeric substances (EPS) and display dimorphic growth, but also on the biofilm substratum, carbon source availability and other factors. Additionally, the transcriptional control over processes like adhesion, biofilm formation, filamentation, and EPS production displays great complexity and diversity within pathogenic yeasts of the Candida genus. These differences not only have implications in the persistence of colonization and infections but also on antifungal resistance typically found in Candida biofilm cells, potentiated by EPS, that functions as a barrier to drug diffusion, and by the overexpression of drug resistance transporters. The ability to interact with different species in in vivo Candida biofilms is also a key factor to consider when dealing with this problem. Despite many challenges, the most promising strategies that are currently available or under development to limit biofilm formation or to eradicate mature biofilms are discussed.
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Candida Biofilms: Threats, Challenges, and Promising Strategies
Cavalheiro, Mafalda; Teixeira, Miguel Cacho
2018-01-01
Candida species are fungal pathogens known for their ability to cause superficial and systemic infections in the human host. These pathogens are able to persist inside the host due to the development of pathogenicity and multidrug resistance traits, often leading to the failure of therapeutic strategies. One specific feature of Candida species pathogenicity is their ability to form biofilms, which protects them from external factors such as host immune system defenses and antifungal drugs. This review focuses on the current threats and challenges when dealing with biofilms formed by Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis, highlighting the differences between the four species. Biofilm characteristics depend on the ability of each species to produce extracellular polymeric substances (EPS) and display dimorphic growth, but also on the biofilm substratum, carbon source availability and other factors. Additionally, the transcriptional control over processes like adhesion, biofilm formation, filamentation, and EPS production displays great complexity and diversity within pathogenic yeasts of the Candida genus. These differences not only have implications in the persistence of colonization and infections but also on antifungal resistance typically found in Candida biofilm cells, potentiated by EPS, that functions as a barrier to drug diffusion, and by the overexpression of drug resistance transporters. The ability to interact with different species in in vivo Candida biofilms is also a key factor to consider when dealing with this problem. Despite many challenges, the most promising strategies that are currently available or under development to limit biofilm formation or to eradicate mature biofilms are discussed. PMID:29487851
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Ureolytic Biomineralization Reduces Proteus mirabilis Biofilm Susceptibility to Ciprofloxacin
Li, Xiaobao; Lu, Nanxi; Brady, Hannah R.
2016-01-01
Ureolytic biomineralization induced by urease-producing bacteria, particularly Proteus mirabilis, is responsible for the formation of urinary tract calculi and the encrustation of indwelling urinary catheters. Such microbial biofilms are challenging to eradicate and contribute to the persistence of catheter-associated urinary tract infections, but the mechanisms responsible for this recalcitrance remain obscure. In this study, we characterized the susceptibility of wild-type (ure+) and urease-negative (ure−) P. mirabilis biofilms to killing by ciprofloxacin. Ure+ biofilms produced fine biomineral precipitates that were homogeneously distributed within the biofilm biomass in artificial urine, while ure− biofilms did not produce biomineral deposits under identical growth conditions. Following exposure to ciprofloxacin, ure+ biofilms showed greater survival (less killing) than ure− biofilms, indicating that biomineralization protected biofilm-resident cells against the antimicrobial. To evaluate the mechanism responsible for this recalcitrance, we observed and quantified the transport of Cy5-conjugated ciprofloxacin into the biofilm by video confocal microscopy. These observations revealed that the reduced susceptibility of ure+ biofilms resulted from hindered delivery of ciprofloxacin into biomineralized regions of the biofilm. Further, biomineralization enhanced retention of viable cells on the surface following antimicrobial exposure. These findings together show that ureolytic biomineralization induced by P. mirabilis metabolism strongly regulates antimicrobial susceptibility by reducing internal solute transport and increasing biofilm stability. PMID:26953206
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Intrinsic and Extrinsic Aspects on Campylobacter jejuni Biofilms
Melo, Roberta T.; Mendonça, Eliane P.; Monteiro, Guilherme P.; Siqueira, Mariana C.; Pereira, Clara B.; Peres, Phelipe A. B. M.; Fernandez, Heriberto; Rossi, Daise A.
2017-01-01
Biofilm represents a way of life that allows greater survival of microorganisms in hostile habitats. Campylobacter jejuni is able to form biofilms in vitro and on surfaces at several points in the poultry production chain. Genetic determinants related to their formation are expressed differently between strains and external conditions are decisive in this respect. Our approach combines phylogenetic analysis and the presence of seven specific genes linked to biofilm formation in association with traditional microbiology techniques, using Mueller Hinton and chicken juice as substrates in order to quantify, classify, determine the composition and morphology of the biomass of simple and mixed biofilms of 30 C. jejuni strains. It also evaluates the inhibition of its formation by biocides commonly used in industry and also by zinc oxide nanoparticles. Genetic analysis showed high heterogeneity with the identification of 23 pulsotypes. Despite the diversity, the presence of flaA, cadF, luxS, dnaJ, htrA, cbrA, and sodB genes in all strains shows the high potential for biofilm formation. This ability was only expressed in chicken juice, where they presented phenotype of a strong biofilm producer, with a mean count of 7.37 log CFU/mL and an ultrastructure characteristic of mature biofilm. The composition of simple and mixed biofilms was predominantly composed by proteins. The exceptions were found in mixed biofilms with Pseudomonas aeruginosa, which includes a carbohydrate-rich matrix, lower ability to sessile form in chicken juice and compact architecture of the biofilm, this aspects are intrinsic to this species. Hypochlorite, chlorhexidine, and peracetic acid were more effective in controlling viable cells of C. jejuni in biofilm, but the existence of tolerant strains indicates exposure to sublethal concentrations and development of adaptation mechanisms. This study shows that in chicken juice C. jejuni presents greater potential in producing mature biofilms. PMID
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Intrinsic and Extrinsic Aspects on Campylobacter jejuni Biofilms.
Melo, Roberta T; Mendonça, Eliane P; Monteiro, Guilherme P; Siqueira, Mariana C; Pereira, Clara B; Peres, Phelipe A B M; Fernandez, Heriberto; Rossi, Daise A
2017-01-01
Biofilm represents a way of life that allows greater survival of microorganisms in hostile habitats. Campylobacter jejuni is able to form biofilms in vitro and on surfaces at several points in the poultry production chain. Genetic determinants related to their formation are expressed differently between strains and external conditions are decisive in this respect. Our approach combines phylogenetic analysis and the presence of seven specific genes linked to biofilm formation in association with traditional microbiology techniques, using Mueller Hinton and chicken juice as substrates in order to quantify, classify, determine the composition and morphology of the biomass of simple and mixed biofilms of 30 C. jejuni strains. It also evaluates the inhibition of its formation by biocides commonly used in industry and also by zinc oxide nanoparticles. Genetic analysis showed high heterogeneity with the identification of 23 pulsotypes. Despite the diversity, the presence of flaA, cadF, luxS, dnaJ, htrA, cbrA , and sodB genes in all strains shows the high potential for biofilm formation. This ability was only expressed in chicken juice, where they presented phenotype of a strong biofilm producer, with a mean count of 7.37 log CFU/mL and an ultrastructure characteristic of mature biofilm. The composition of simple and mixed biofilms was predominantly composed by proteins. The exceptions were found in mixed biofilms with Pseudomonas aeruginosa , which includes a carbohydrate-rich matrix, lower ability to sessile form in chicken juice and compact architecture of the biofilm, this aspects are intrinsic to this species. Hypochlorite, chlorhexidine, and peracetic acid were more effective in controlling viable cells of C. jejuni in biofilm, but the existence of tolerant strains indicates exposure to sublethal concentrations and development of adaptation mechanisms. This study shows that in chicken juice C. jejuni presents greater potential in producing mature biofilms.
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Quantitative analysis of in vivo mucosal bacterial biofilms.
Singhal, Deepti; Boase, Sam; Field, John; Jardeleza, Camille; Foreman, Andrew; Wormald, Peter-John
2012-01-01
Quantitative assays of mucosal biofilms on ex vivo samples are challenging using the currently applied specialized microscopic techniques to identify them. The COMSTAT2 computer program has been applied to in vitro biofilm models for quantifying biofilm structures seen on confocal scanning laser microscopy (CSLM). The aim of this study was to quantify Staphylococcus aureus (S. aureus) biofilms seen via CSLM on ex situ samples of sinonasal mucosa, using the COMSTAT2 program. S. aureus biofilms were grown in frontal sinuses of 4 merino sheep as per a previously standardized sheep sinusitis model for biofilms. Two sinonasal mucosal samples, 10 mm × 10 mm in size, from each of the 2 sinuses of the 4 sheep were analyzed for biofilm presence with Baclight stain and CSLM. Two random image stacks of mucosa with S. aureus biofilm were recorded from each sample, and analyzed using COMSTAT2 software that translates image stacks into a simplified 3-dimensional matrix of biofilm mass by eliminating surrounding host tissue. Three independent observers analyzed images using COMSTAT2 and 3 repeated rounds of analyses were done to calculate biofilm biomass. The COMSTAT2 application uses an observer-dependent threshold setting to translate CSLM biofilm images into a simplified 3-dimensional output for quantitative analysis. Intraclass correlation coefficient (ICC) between thresholds set by the 3 observers for each image stacks was 0.59 (p = 0.0003). Threshold values set at different points of time by a single observer also showed significant correlation as seen by ICC of 0.80 (p < 0.001). COMSTAT2 can be applied to quantify and study the complex 3-dimensional biofilm structures that are recorded via CSLM on mucosal tissue like the sinonasal mucosa. Copyright © 2011 American Rhinologic Society-American Academy of Otolaryngic Allergy, LLC.
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Wunnoo, Suttiwan; Saising, Jongkon; Voravuthikunchai, Supayang Piyawan
2017-02-01
Virulence enzymes and biofilm a play crucial role in the pathogenesis of Propionibacterium acnes, a major causative agent of acne vulgaris. In the present study, the effects of rhodomyrtone, a pure compound identified from Rhodomyrtus tomentosa (Aiton) Hassk. leaves extract against enzyme production and biofilm formation production by 5 clinical isolates and a reference strain were evaluated. The degree of hydrolysis by both lipase and protease enzymes significantly decreased upon treatment with the compound at 0.125-0.25 μg/mL (p < 0.05). Lipolytic zones significantly reduced in all isolates while decrease in proteolytic activities was found only in 50% of the isolates. Rhodomyrtone at 1/16MIC and 1/8MIC caused significant reduction in biofilm formation of the clinical isolates (p < 0.05). Percentage viability of P. acnes within mature biofilm upon treated with the compound at 4MIC and 8MIC ranged between 40% and 85%. Pronounced properties of rhodomyrtone suggest a path towards developing a novel anti-acne agent. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Comparative analysis of quantitative methodologies for Vibrionaceae biofilms.
Chavez-Dozal, Alba A; Nourabadi, Neda; Erken, Martina; McDougald, Diane; Nishiguchi, Michele K
2016-11-01
Multiple symbiotic and free-living Vibrio spp. grow as a form of microbial community known as a biofilm. In the laboratory, methods to quantify Vibrio biofilm mass include crystal violet staining, direct colony-forming unit (CFU) counting, dry biofilm cell mass measurement, and observation of development of wrinkled colonies. Another approach for bacterial biofilms also involves the use of tetrazolium (XTT) assays (used widely in studies of fungi) that are an appropriate measure of metabolic activity and vitality of cells within the biofilm matrix. This study systematically tested five techniques, among which the XTT assay and wrinkled colony measurement provided the most reproducible, accurate, and efficient methods for the quantitative estimation of Vibrionaceae biofilms.
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Microbial indicators in natural biofilms developed in the riverbed.
Hirotani, Hiroshi; Yoshino, Miyuki
2010-01-01
Microbial indicators such as heterotrophic bacteria, total coliforms, and Escherichia coli in naturally developed riverbed biofilms were investigated. Pebbles covered with natural biofilm were sampled directly from the riverbed at sampling stations ranging from the upstream region within a quasi-national park to the midstream in the urban district. Heterotrophic bacteria densities in biofilm positively correlated with stream discharge. E. coli densities in biofilm positively correlated with temperature, which suggests the growth in the biofilm. It was considered that the attachment of planktonic bacteria to biofilm was negligible. The biofilm may serve as an internal source of false positive indication of fecal contamination in the water column.
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Stepanović, Srdjan; Vuković, Dragana; Hola, Veronika; Di Bonaventura, Giovanni; Djukić, Slobodanka; Cirković, Ivana; Ruzicka, Filip
2007-08-01
The details of all steps involved in the quantification of biofilm formation in microtiter plates are described. The presented protocol incorporates information on assessment of biofilm production by staphylococci, gained both by direct experience as well as by analysis of methods for assaying biofilm production. The obtained results should simplify quantification of biofilm formation in microtiter plates, and make it more reliable and comparable among different laboratories.
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Characterization of Mechanical Properties of Microbial Biofilms
NASA Astrophysics Data System (ADS)
Callison, Elizabeth; Gose, James; Perlin, Marc; Ceccio, Steven
2017-11-01
The physical properties of microbial biofilms grown subject to shear flows determine the form and mechanical characteristics of the biofilm structure, and consequently, the turbulent interactions over and through the biofilm. These biofilms - sometimes referred to as slime - are comprised of microbial cells and extracellular polymeric substance (EPS) matrices that surround the multicellular communities. Some of the EPSs take the form of streamers that tend to oscillate in flows, causing increased turbulent mixing and drag. As the presence of EPS governs the compliance and overall stability of the filamentous streamers, investigation of the mechanical properties of biofilms may also inform efforts to understand hydrodynamic performance of fouled systems. In this study, a mixture of four diatom genera was grown under turbulent shear flow on test panels. The mechanical properties and hydrodynamic performance of the biofilm were investigated using rheology and turbulent flow studies in the Skin-Friction Flow Facility at the University of Michigan. The diatoms in the mixture of algae were identified, and the elastic and viscous moduli were determined from small-amplitude oscillations, while a creep test was used to evaluate the biofilm compliance.
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Design of a spaceflight biofilm experiment
NASA Astrophysics Data System (ADS)
Zea, Luis; Nisar, Zeena; Rubin, Phil; Cortesão, Marta; Luo, Jiaqi; McBride, Samantha A.; Moeller, Ralf; Klaus, David; Müller, Daniel; Varanasi, Kripa K.; Muecklich, Frank; Stodieck, Louis
2018-07-01
Biofilm growth has been observed in Soviet/Russian (Salyuts and Mir), American (Skylab), and International (ISS) Space Stations, sometimes jeopardizing key equipment like spacesuits, water recycling units, radiators, and navigation windows. Biofilm formation also increases the risk of human illnesses and therefore needs to be well understood to enable safe, long-duration, human space missions. Here, the design of a NASA-supported biofilm in space project is reported. This new project aims to characterize biofilm inside the International Space Station in a controlled fashion, assessing changes in mass, thickness, and morphology. The space-based experiment also aims at elucidating the biomechanical and transcriptomic mechanisms involved in the formation of a "column-and-canopy" biofilm architecture that has previously been observed in space. To search for potential solutions, different materials and surface topologies will be used as the substrata for microbial growth. The adhesion of bacteria to surfaces and therefore the initial biofilm formation is strongly governed by topographical surface features of about the bacterial scale. Thus, using Direct Laser-Interference Patterning, some material coupons will have surface patterns with periodicities equal, above or below the size of bacteria. Additionally, a novel lubricant-impregnated surface will be assessed for potential Earth and spaceflight anti-biofilm applications. This paper describes the current experiment design including microbial strains and substrata materials and nanotopographies being considered, constraints and limitations that arise from performing experiments in space, and the next steps needed to mature the design to be spaceflight-ready.
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Fluorescence lifetime imaging of oxygen in dental biofilm
NASA Astrophysics Data System (ADS)
Gerritsen, Hans C.; de Grauw, Cees J.
2000-12-01
Dental biofilm consists of micro-colonies of bacteria embedded in a matrix of polysaccharides and salivary proteins. pH and oxygen concentration are of great importance in dental biofilm. Both can be measured using fluorescence techniques. The imaging of dental biofilm is complicated by the thickness of the biofilms that can be up to several hundred micrometers thick. Here, we employed a combination of two-photon excitation microscopy with fluorescence lifetime imaging to quantify the oxygen concentration in dental biofilm. Collisional quenching of fluorescent probes by molecular oxygen leads to a reduction of the fluorescence lifetime of the probe. We employed this mechanism to measure the oxygen concentration distribution in dental biofilm by means of fluorescence lifetime imaging. Here, TRIS Ruthenium chloride hydrate was used as an oxygen probe. A calibration procedure on buffers was use to measure the lifetime response of this Ruthenium probe. The results are in agreement with the Stern-Volmer equation. A linear relation was found between the ratio of the unquenched and the quenched lifetime and the oxygen concentration. The biofilm fluorescence lifetime imaging results show a strong oxygen gradient at the buffer - biofilm interface and the average oxygen concentration in the biofilm amounted to 50 μM.
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Modeling antimicrobial tolerance and treatment of heterogeneous biofilms.
Zhao, Jia; Seeluangsawat, Paisa; Wang, Qi
2016-12-01
A multiphasic, hydrodynamic model for spatially heterogeneous biofilms based on the phase field formulation is developed and applied to analyze antimicrobial tolerance of biofilms by acknowledging the existence of persistent and susceptible cells in the total population of bacteria. The model implements a new conversion rate between persistent and susceptible cells and its homogeneous dynamics is bench-marked against a known experiment quantitatively. It is then discretized and solved on graphic processing units (GPUs) in 3-D space and time. With the model, biofilm development and antimicrobial treatment of biofilms in a flow cell are investigated numerically. Model predictions agree qualitatively well with available experimental observations. Specifically, numerical results demonstrate that: (i) in a flow cell, nutrient, diffused in solvent and transported by hydrodynamics, has an apparent impact on persister formation, thereby antimicrobial persistence of biofilms; (ii) dosing antimicrobial agents inside biofilms is more effective than dosing through diffusion in solvent; (iii) periodic dosing is less effective in antimicrobial treatment of biofilms in a nutrient deficient environment than in a nutrient sufficient environment. This model provides us with a simulation tool to analyze mechanisms of biofilm tolerance to antimicrobial agents and to derive potentially optimal dosing strategies for biofilm control and treatment. Copyright © 2016 Elsevier Inc. All rights reserved.
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[Effects of traditional Chinese medicine on oral bacteria biofilm].
Zhao, Jin; Li, Ji-yao; Zhu, Bing; Zhou, Xue-dong
2007-10-01
To investigate the effects of compounds of Galla chinensis extract (GCE) and Nidus vespae extract-1 (WVE1) on oral bacteria biofilm structure and activity and to determine the possibility of caries prevention by the compounds. The morphology and activity of treated-oral bacterial biofilm and untreated-oral bacterial biofilm were observed by using fluorescence microscope in combination of idio-fluorochrome to label the died and living bacteria. The visible light semiquantitative method was used to measure biomass glucosyltransferase (GTF, A620) values and to determine the effects of active compounds of GCE and NVE1 on GTF of oral bacteria biofilm. The living bacteria in the untreated 24 h bacterial biofilm was dominant, and only a small number of died bacteria were found, the biofilm structure was regular and clear. GCE, GCE-B and NVE1 could inhibit the bacteria in the dental biofilm, which showed significant difference with the negative control. GCE and NVE1 could also inhibit GTF activity of 24 h bacterial biofilm in comparison with the negative control. The traditional Chinese medicine Galla chinensis and Nidus vespae could not only inhibit bacteria growth on oral bacterial biofilm, but also function by adjusting biofilm structure, composition and GTF activity of 24 h bacterial biofilm.
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Carrel, Maxence; Morales, Verónica L; Beltran, Mario A; Derlon, Nicolas; Kaufmann, Rolf; Morgenroth, Eberhard; Holzner, Markus
2018-05-01
This study investigates the functional correspondence between porescale hydrodynamics, mass transfer, pore structure and biofilm morphology during progressive biofilm colonization of a porous medium. Hydrodynamics and the structure of both the porous medium and the biofilm are experimentally measured with 3D particle tracking velocimetry and micro X-ray Computed Tomography, respectively. The analysis focuses on data obtained in a clean porous medium after 36 h of biofilm growth. Registration of the particle tracking and X-ray data sets allows to delineate the interplay between porous medium geometry, hydrodynamic and mass transfer processes on the morphology of the developing biofilm. A local analysis revealed wide distributions of wall shear stresses and concentration boundary layer thicknesses. The spatial distribution of the biofilm patches uncovered that the wall shear stresses controlled the biofilm development. Neither external nor internal mass transfer limitations were noticeable in the considered system, consistent with the excess supply of nutrient and electron acceptors. The wall shear stress remained constant in the vicinity of the biofilm but increased substantially elsewhere. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Managing the complexity of a dynamic biofilm.
Thomas, John G; Nakaishi, Lindsay A
2006-11-01
This article provides an overview of the history of oral microbiology, a discussion of dental plaque as both a microbial community and a biofilm, and a review of the measures available to control the oral microflora. The authors reviewed the literature related to oral microbiology and associated infectious diseases. They also examined articles that detailed the structure and physiology of biofilms, including dental plaque biofilms. Biofilms cannot be eliminated. The pathogenic nature of the dental plaque biofilm can be diminished in the oral cavity by reducing the bioburden and effectively maintaining a normal oral flora via oral hygiene procedures that include daily toothbrushing, flossing and rinsing with an antimicrobial mouthrinse. An oral hygiene regimen that includes rinsing with an antimicrobial mouthrinse is a practical approach to the prevention and management of periodontal diseases. This strategy may have wider benefits when the link between periodontal disease and certain systemic diseases is considered. An effective oral hygiene regimen can help control dental plaque biofilm and associated periodontal diseases.
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The Extracellular Matrix of Fungal Biofilms.
Mitchell, Kaitlin F; Zarnowski, Robert; Andes, David R
A key feature of biofilms is their production of an extracellular matrix. This material covers the biofilm cells, providing a protective barrier to the surrounding environment. During an infection setting, this can include such offenses as host cells and products of the immune system as well as drugs used for treatment. Studies over the past two decades have revealed the matrix from different biofilm species to be as diverse as the microbes themselves. This chapter will review the composition and roles of matrix from fungal biofilms, with primary focus on Candida species, Saccharomyces cerevisiae, Aspergillus fumigatus, and Cryptococcus neoformans. Additional coverage will be provided on the antifungal resistance proffered by the Candida albicans matrix, which has been studied in the most depth. A brief section on the matrix produced by bacterial biofilms will be provided for comparison. Current tools for studying the matrix will also be discussed, as well as suggestions for areas of future study in this field.
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Monochloramine Cometabolism by Nitrifying Biofilm Relevant ...
Recently, biological monochloramine removal (i.e., cometabolism) by a pure culture ammonia–oxidizing bacteria, Nitrosomonas europaea, and a nitrifying mixed–culture have been shown to increase monochloramine demand. Although important, these previous suspended culture batch kinetic experiments were not representative of drinking water distribution systems where bacteria grow predominantly as biofilm attached to pipe walls or sediments and physiological differences may exist between suspension and biofilm growth. Therefore, the current research was an important next step in extending the previous results to investigate monochloramine cometabolism by biofilm grown in annular reactors under drinking water relevant conditions. Estimated monochloramine cometabolism kinetics were similar to those of ammonia metabolism, and monochloramine cometabolism was a significant loss mechanism (25–40% of the observed monochloramine loss). These results demonstrated that monochloramine cometabolism occurred in drinking water relevant nitrifying biofilm; thus, cometabolism may be a significant contribution to monochloramine loss during nitrification episodes in distribution systems. Investigate whether or not nitrifying biofilm can biologically transform monochloramine under drinking water relevant conditions.
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Xiang, Hua; Cao, Fengjiao; Ming, Di; Zheng, Yanyang; Dong, Xiaoyun; Zhong, Xiaobo; Mu, Dan; Li, Bangbang; Zhong, Ling; Cao, Junjie; Wang, Lin; Ma, Hongxia; Wang, Tiedong; Wang, Dacheng
2017-09-01
Staphylococcus aureus (S. aureus) biofilms are clinically serious and play a critical role in the persistence of chronic infections due to their ability to resist antibiotics. The inhibition of biofilm formation is viewed as a new strategy for the prevention of S. aureus infections. Here, we demonstrated that minimum inhibitory concentrations (MICs) of aloe-emodin exhibited no bactericidal activity against S. aureus but affected S. aureus biofilm development in a dose-dependent manner. Further studies indicated that aloe-emodin specifically inhibits the initial adhesion and proliferation stages of S. aureus biofilm development. Scanning electron microscopy (SEM) indicated that the S. aureus ATCC29213 biofilm extracellular matrix is mainly composed of protein. Laser scanning confocal microscope assays revealed that aloe-emodin treatment primarily inhibited extracellular protein production. Moreover, the Congo red assay showed that aloe-emodin also reduced the accumulation of polysaccharide intercellular adhesin (PIA) on the cell surface. These findings will provide new insights into the mode of action of aloe-emodin in the treatment of infections by S. aureus biofilms.
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Lattif, Ali Abdul; Mukherjee, Pranab K; Chandra, Jyotsna; Roth, Mary R; Welti, Ruth; Rouabhia, Mahmoud; Ghannoum, Mahmoud A
2011-11-01
Candida albicans-associated bloodstream infections are linked to the ability of this yeast to form biofilms. In this study, we used lipidomics to compare the lipid profiles of C. albicans biofilms and planktonic cells, in early and mature developmental phases. Our results showed that significant differences exist in lipid composition in both developmental phases. Biofilms contained higher levels of phospholipid and sphingolipids than planktonic cells (nmol per g biomass, P<0.05 for all comparisons). In the early phase, levels of lipid in most classes were significantly higher in biofilms compared to planktonic cells (P≤0.05). The ratio of phosphatidylcholine to phosphatidylethanolamine was lower in biofilms compared to planktonic cells in both early (1.17 vs 2.52, P≤0.001) and late (2.34 vs 3.81, P≤0.001) developmental phases. The unsaturation index of phospholipids decreased with time, with this effect being particularly strong for biofilms. Inhibition of the biosynthetic pathway for sphingolipid [mannosyl diinositolphosphoryl ceramide, M(IP)₂C] by myriocin or aureobasidin A, and disruption of the gene encoding inositolphosphotransferase (Ipt1p), abrogated the ability of C. albicans to form biofilms. The differences in lipid profiles between biofilms and planktonic Candida cells may have important implications for the biology and antifungal resistance of biofilms.
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Biofilm Formation Characteristics of Pseudomonas lundensis Isolated from Meat.
Liu, Yong-Ji; Xie, Jing; Zhao, Li-Jun; Qian, Yun-Fang; Zhao, Yong; Liu, Xiao
2015-12-01
Biofilms formations of spoilage and pathogenic bacteria on food or food contact surfaces have attracted increasing attention. These events may lead to a higher risk of food spoilage and foodborne disease transmission. While Pseudomonas lundensis is one of the most important bacteria that cause spoilage in chilled meat, its capability for biofilm formation has been seldom reported. Here, we investigated biofilm formation characteristics of P. lundensis mainly by using crystal violet staining, and confocal laser scanning microscopy (CLSM). The swarming and swimming motility, biofilm formation in different temperatures (30, 10, and 4 °C) and the protease activity of the target strain were also assessed. The results showed that P. lundensis showed a typical surface-associated motility and was quite capable of forming biofilms in different temperatures (30, 10, and 4 °C). The strain began to adhere to the contact surfaces and form biofilms early in the 4 to 6 h. The biofilms began to be formed in massive amounts after 12 h at 30 °C, and the extracellular polysaccharides increased as the biofilm structure developed. Compared with at 30 °C, more biofilms were formed at 4 and 10 °C even by a low bacterial density. The protease activity in the biofilm was significantly correlated with the biofilm formation. Moreover, the protease activity in biofilm was significantly higher than that of the corresponding planktonic cultures after cultured 12 h at 30 °C. © 2015 Institute of Food Technologists®
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Fernández-Rivero, Marcelo Ernesto; Del Pozo, José L; Valentín, Amparo; Fornes, Victoria; Molina de Diego, Araceli; Pemán, Javier; Cantón, Emilia
Current therapeutic strategies have a limited efficacy against Candida biofilms that form on the surfaces of biomedical devices. Few studies have evaluated the activity of antifungal agents against Candida tropicalis biofilms. To evaluate the activity of amphotericin B (AMB) and anidulafungin (AND), alone and in combination, against C. tropicalis biofilms developed on polytetrafluoroethylene (teflon -PTFE) and titanium surfaces using time-kill assays. Assays were performed using the CDC Biofilm Reactor equipped with PTFE and titanium disks with C. tropicalis biofilms after 24h of maturation. The concentrations assayed were 40mg/l for AMB and 8mg/l for AND, both alone and combined. After 24, 48 and 72h of exposure to the antifungals, the cfu/cm 2 was determined by a vortexing-sonication procedure. AMB reduced biofilm viable cells attached to PTFE and titanium by ≥99% and AND by 89.3% on PTFE and 96.8% on titanium. The AMB+AND combination was less active than AMB alone, both on PTFE (decrease of cfu/cm 2 3.09 Log 10 vs. 1.08 when combined) and titanium (4.51 vs. 1.53 when combined), being the interaction irrelevant on both surfaces. AMB is more active than AND against C. tropicalis biofilms. Yeast killing rates are higher on titanium than on PTFE surfaces. The combination of AMB plus AND is less effective than AMB alone on both surfaces. Copyright © 2017 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.
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Predation Response of Vibrio fischeri Biofilms to Bacterivorus Protists
Chavez-Dozal, Alba; Gorman, Clayton; Erken, Martina; Steinberg, Peter D.; McDougald, Diane
2013-01-01
Vibrio fischeri proliferates in a sessile, stable community known as a biofilm, which is one alternative survival strategy of its life cycle. Although this survival strategy provides adequate protection from abiotic factors, marine biofilms are still susceptible to grazing by bacteria-consuming protozoa. Subsequently, grazing pressure can be controlled by certain defense mechanisms that confer higher biofilm antipredator fitness. In the present work, we hypothesized that V. fischeri exhibits an antipredator fitness behavior while forming biofilms. Different predators representing commonly found species in aquatic populations were examined, including the flagellates Rhynchomonas nasuta and Neobodo designis (early biofilm feeders) and the ciliate Tetrahymena pyriformis (late biofilm grazer). V. fischeri biofilms included isolates from both seawater and squid hosts (Euprymna and Sepiola species). Our results demonstrate inhibition of predation by biofilms, specifically, isolates from seawater. Additionally, antiprotozoan behavior was observed to be higher in late biofilms, particularly toward the ciliate T. pyriformis; however, inhibitory effects were found to be widespread among all isolates tested. These results provide an alternative explanation for the adaptive advantage and persistence of V. fischeri biofilms and provide an important contribution to the understanding of defensive mechanisms that exist in the out-of-host environment. PMID:23144127
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Extracellular matrix structure governs invasion resistance in bacterial biofilms.
Nadell, Carey D; Drescher, Knut; Wingreen, Ned S; Bassler, Bonnie L
2015-08-01
Many bacteria are highly adapted for life in communities, or biofilms. A defining feature of biofilms is the production of extracellular matrix that binds cells together. The biofilm matrix provides numerous fitness benefits, including protection from environmental stresses and enhanced nutrient availability. Here we investigate defense against biofilm invasion using the model bacterium Vibrio cholerae. We demonstrate that immotile cells, including those identical to the biofilm resident strain, are completely excluded from entry into resident biofilms. Motile cells can colonize and grow on the biofilm exterior, but are readily removed by shear forces. Protection from invasion into the biofilm interior is mediated by the secreted protein RbmA, which binds mother-daughter cell pairs to each other and to polysaccharide components of the matrix. RbmA, and the invasion protection it confers, strongly localize to the cell lineages that produce it.
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The ecology and biogeochemistry of stream biofilms.
Battin, Tom J; Besemer, Katharina; Bengtsson, Mia M; Romani, Anna M; Packmann, Aaron I
2016-04-01
Streams and rivers form dense networks, shape the Earth's surface and, in their sediments, provide an immensely large surface area for microbial growth. Biofilms dominate microbial life in streams and rivers, drive crucial ecosystem processes and contribute substantially to global biogeochemical fluxes. In turn, water flow and related deliveries of nutrients and organic matter to biofilms constitute major constraints on microbial life. In this Review, we describe the ecology and biogeochemistry of stream biofilms and highlight the influence of physical and ecological processes on their structure and function. Recent advances in the study of biofilm ecology may pave the way towards a mechanistic understanding of the effects of climate and environmental change on stream biofilms and the biogeochemistry of stream ecosystems.
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The Roles of Biofilm Conductivity and Donor Substrate Kinetics in a Mixed-Culture Biofilm Anod
We experimentally assessed kinetics and thermodynamics of electron transfer (ET) from the donor substrate (acetate) to the anode for a mixed-culture biofilm anode. We interpreted the results with a modified biofilm-conduction model consisting of three ET steps: (1) intracellular...
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Behnke, Sabrina; Parker, Albert E; Woodall, Dawn; Camper, Anne K
2011-10-01
Although the detachment of cells from biofilms is of fundamental importance to the dissemination of organisms in both public health and clinical settings, the disinfection efficacies of commonly used biocides on detached biofilm particles have not been investigated. Therefore, the question arises whether cells in detached aggregates can be killed with disinfectant concentrations sufficient to inactivate planktonic cells. Burkholderia cepacia and Pseudomonas aeruginosa were grown in standardized laboratory reactors as single species and in coculture. Cluster size distributions in chemostats and biofilm reactor effluent were measured. Chlorine susceptibility was assessed for planktonic cultures, attached biofilm, and particles and cells detached from the biofilm. Disinfection tolerance generally increased with a higher percentage of larger cell clusters in the chemostat and detached biofilm. Samples with a lower percentage of large clusters were more easily disinfected. Thus, disinfection tolerance depended on the cluster size distribution rather than sample type for chemostat and detached biofilm. Intact biofilms were more tolerant to chlorine independent of species. Homogenization of samples led to significantly increased susceptibility in all biofilm samples as well as detached clusters for single-species B. cepacia, B. cepacia in coculture, and P. aeruginosa in coculture. The disinfection efficacy was also dependent on species composition; coculture was advantageous to the survival of both species when grown as a biofilm or as clusters detached from biofilm but, surprisingly, resulted in a lower disinfection tolerance when they were grown as a mixed planktonic culture.
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Treatment of Oral Biofilms by a D-Enantiomeric Peptide.
Zhang, Tian; Wang, Zhejun; Hancock, Robert E W; de la Fuente-Núñez, César; Haapasalo, Markus
2016-01-01
Almost all dental diseases are caused by biofilms that consist of multispecies communities. DJK-5, which is a short D-enantiomeric, protease-resistant peptide with broad-spectrum anti-biofilm activity, was tested for its effect on oral multispecies biofilms. Peptide DJK-5 at 10 μg/mL effectively prevented the growth of these microbes in culture media in a time-dependent manner. In addition to the prevention of growth, peptide DJK-5 completely killed both Streptococcus mutans and Enterococcus faecalis suspended from biofilms after 30 minutes of incubation in liquid culture media. DJK-5 also led to the effective killing of microbes in plaque biofilm. The proportion of bacterial cells killed by 10 μg/mL of DJK-5 was similar after 1 and 3 days, both exceeding 85%. DJK-5 was able to significantly prevent biofilm formation over 3 days (P = 0.000). After 72 hours of exposure, DJK-5 significantly reduced and almost completely prevented plaque biofilm production by more than 90% of biovolume compared to untreated controls (P = 0.000). The proportion of dead biofilm bacteria at the 10 μg/mL DJK-5 concentration was similar for 1- and 3-day-old biofilms, whereby >86% of the bacteria were killed. DJK-5 was also able to kill >79% and >85% of bacteria, respectively, after one-time and three brief treatments of 3-day-old biofilms. The combination of DJK-5 and chlorhexidine showed the best bacterial killing among all treatments, with ~83% and >88% of bacterial cells killed after 1 and 3 minutes, respectively. No significant difference was found in the percentage of biofilm killing amongst three donor plaque samples after DJK-5 treatment. In particular, DJK-5 showed strong performance in inhibiting biofilm development and eradicating pre-formed oral biofilms compared to L-enantiomeric peptide 1018. DJK-5 was very effective against oral biofilms when used alone or combined with chlorhexidine, and may be a promising agent for use in oral anti-biofilm strategies in the future.
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Molecular mechanisms involved in Bacillus subtilis biofilm formation
Mielich-Süss, Benjamin; Lopez, Daniel
2014-01-01
Summary Biofilms are the predominant lifestyle of bacteria in natural environments, and they severely impact our societies in many different fashions. Therefore, biofilm formation is a topic of growing interest in microbiology, and different bacterial models are currently studied to better understand the molecular strategies that bacteria undergo to build biofilms. Among those, biofilms of the soil-dwelling bacterium Bacillus subtilis are commonly used for this purpose. Bacillus subtilis biofilms show remarkable architectural features that are a consequence of sophisticated programs of cellular specialization and cell-cell communication within the community. Many laboratories are trying to unravel the biological role of the morphological features of biofilms, as well as exploring the molecular basis underlying cellular differentiation. In this review, we present a general perspective of the current state of knowledge of biofilm formation in B. subtilis. In particular, a special emphasis is placed on summarizing the most recent discoveries in the field and integrating them into the general view of these truly sophisticated microbial communities. PMID:24909922
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Bacterial interactions in dental biofilm development.
Hojo, K; Nagaoka, S; Ohshima, T; Maeda, N
2009-11-01
Recent analyses with ribosomal RNA-based technologies have revealed the diversity of bacterial populations within dental biofilms, and have highlighted their important contributions to oral health and disease. Dental biofilms are exceedingly complex and multispecies ecosystems, where oral bacteria interact cooperatively or competitively with other members. Bacterial interactions that influence dental biofilm communities include various different mechanisms. During the early stage of biofilm formation, it is known that planktonic bacterial cells directly attach to surfaces of the oral cavity or indirectly bind to other bacterial cells that have already colonized. Adherence through co-aggregation may be critical for the temporary retention of bacteria on dental surfaces, and may facilitate eventual bacterial colonization. It is likely that metabolic communication, genetic exchange, production of inhibitory factors (e.g., bacteriocins, hydrogen peroxide, etc.), and quorum-sensing are pivotal regulatory factors that determine the bacterial composition and/or metabolism. Since each bacterium can easily access a neighboring bacterial cell and its metabolites, genetic exchanges and metabolic communication may occur frequently in dental biofilms. Quorum-sensing is defined as gene regulation in response to cell density, which influences various functions, e.g., virulence and bacteriocin production. In this review, we discuss these important interactions among oral bacteria within the dental biofilm communities.
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Bacteriophage Lysin CF-301, a Potent Antistaphylococcal Biofilm Agent
Khan, Babar K.; Raz, Assaf; Rotolo, Jimmy A.; Wittekind, Michael
2017-01-01
ABSTRACT Biofilms pose a unique therapeutic challenge because of the antibiotic tolerance of constituent bacteria. Treatments for biofilm-based infections represent a major unmet medical need, requiring novel agents to eradicate mature biofilms. Our objective was to evaluate bacteriophage lysin CF-301 as a new agent to target Staphylococcus aureus biofilms. We used minimum biofilm-eradicating concentration (MBEC) assays on 95 S. aureus strains to obtain a 90% MBEC (MBEC90) value of ≤0.25 μg/ml for CF-301. Mature biofilms of coagulase-negative staphylococci, Streptococcus pyogenes, and Streptococcus agalactiae were also sensitive to disruption, with MBEC90 values ranging from 0.25 to 8 μg/ml. The potency of CF-301 was demonstrated against S. aureus biofilms formed on polystyrene, glass, surgical mesh, and catheters. In catheters, CF-301 removed all biofilm within 1 h and killed all released bacteria by 6 h. Mixed-species biofilms, formed by S. aureus and Staphylococcus epidermidis on several surfaces, were removed by CF-301, as were S. aureus biofilms either enriched for small-colony variants (SCVs) or grown in human synovial fluid. The antibacterial activity of CF-301 was further demonstrated against S. aureus persister cells in exponential-phase and stationary-phase populations. Finally, the antibiofilm activity of CF-301 was greatly improved in combinations with the cell wall hydrolase lysostaphin when tested against a range of S. aureus strains. In all, the data show that CF-301 is highly effective at disrupting biofilms and killing biofilm bacteria, and, as such, it may be an efficient new agent for treating staphylococcal infections with a biofilm component. PMID:28461319
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Bacteriophage Lysin CF-301, a Potent Antistaphylococcal Biofilm Agent.
Schuch, Raymond; Khan, Babar K; Raz, Assaf; Rotolo, Jimmy A; Wittekind, Michael
2017-07-01
Biofilms pose a unique therapeutic challenge because of the antibiotic tolerance of constituent bacteria. Treatments for biofilm-based infections represent a major unmet medical need, requiring novel agents to eradicate mature biofilms. Our objective was to evaluate bacteriophage lysin CF-301 as a new agent to target Staphylococcus aureus biofilms. We used minimum biofilm-eradicating concentration (MBEC) assays on 95 S. aureus strains to obtain a 90% MBEC (MBEC 90 ) value of ≤0.25 μg/ml for CF-301. Mature biofilms of coagulase-negative staphylococci, Streptococcus pyogenes , and Streptococcus agalactiae were also sensitive to disruption, with MBEC 90 values ranging from 0.25 to 8 μg/ml. The potency of CF-301 was demonstrated against S. aureus biofilms formed on polystyrene, glass, surgical mesh, and catheters. In catheters, CF-301 removed all biofilm within 1 h and killed all released bacteria by 6 h. Mixed-species biofilms, formed by S. aureus and Staphylococcus epidermidis on several surfaces, were removed by CF-301, as were S. aureus biofilms either enriched for small-colony variants (SCVs) or grown in human synovial fluid. The antibacterial activity of CF-301 was further demonstrated against S. aureus persister cells in exponential-phase and stationary-phase populations. Finally, the antibiofilm activity of CF-301 was greatly improved in combinations with the cell wall hydrolase lysostaphin when tested against a range of S. aureus strains. In all, the data show that CF-301 is highly effective at disrupting biofilms and killing biofilm bacteria, and, as such, it may be an efficient new agent for treating staphylococcal infections with a biofilm component. Copyright © 2017 American Society for Microbiology.
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Extracellular DNA in single- and multiple-species unsaturated biofilms.
Steinberger, R E; Holden, P A
2005-09-01
The extracellular polymeric substances (EPS) of bacterial biofilms form a hydrated barrier between cells and their external environment. Better characterization of EPS could be useful in understanding biofilm physiology. The EPS are chemically complex, changing with both bacterial strain and culture conditions. Previously, we reported that Pseudomonas aeruginosa unsaturated biofilm EPS contains large amounts of extracellular DNA (eDNA) (R. E. Steinberger, A. R. Allen, H. G. Hansma, and P. A. Holden, Microb. Ecol. 43:416-423, 2002). Here, we investigated the compositional similarity of eDNA to cellular DNA, the relative quantity of eDNA, and the terminal restriction fragment length polymorphism (TRFLP) community profile of eDNA in multiple-species biofilms. By randomly amplified polymorphic DNA analysis, cellular DNA and eDNA appear identical for P. aeruginosa biofilms. Significantly more eDNA was produced in P. aeruginosa and Pseudomonas putida biofilms than in Rhodococcus erythropolis or Variovorax paradoxus biofilms. While the amount of eDNA in dual-species biofilms was of the same order of magnitude as that of of single-species biofilms, the amounts were not predictable from single-strain measurements. By the Shannon diversity index and principle components analysis of TRFLP profiles generated from 16S rRNA genes, eDNA of four-species biofilms differed significantly from either cellular or total DNA of the same biofilm. However, total DNA- and cellular DNA-based TRFLP analyses of this biofilm community yielded identical results. We conclude that extracellular DNA production in unsaturated biofilms is species dependent and that the phylogenetic information contained in this DNA pool is quantifiable and distinct from either total or cellular DNA.
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Biofilm formation on titanium implants counteracted by grafting gallium and silver ions.
Cochis, Andrea; Azzimonti, Barbara; Della Valle, Cinzia; Chiesa, Roberto; Arciola, Carla Renata; Rimondini, Lia
2015-03-01
Biofilm-associated infections remain the leading cause of implant failure. Thanks to its established biocompatibility and biomechanical properties, titanium has become one of the most widely used materials for bone implants. Engineered surface modifications of titanium able to thwart biofilm formation while endowing a safe anchorage to eukaryotic cells are being progressively developed. Here surfaces of disks of commercial grade 2 titanium for bone implant were grafted with gallium and silver ions by anodic spark deposition. Scanning electron microscopy of the surface morphology and energy dispersive X-ray spectroscopy were used for characterization. Gallium-grafted titanium was evaluated in comparison with silver-grafted titanium for both in vivo and in vitro antibiofilm properties and for in vitro compatibility with human primary gingival fibroblasts. Surface-modified materials showed: (i) homogeneous porous morphology, with pores of micrometric size; (ii) absence of cytotoxic effects; (iii) ability to support in vitro the adhesion and spreading of gingival fibroblasts; and (iv) antibiofilm properties. Although both silver and gallium exhibited in vitro strong antibacterial properties, in vivo gallium was significantly more effective than silver in reducing number and viability of biofilm bacteria colonies. Gallium-based treatments represent promising titanium antibiofilm coatings to develop new bone implantable devices for oral, maxillofacial, and orthopedic applications. © 2014 Wiley Periodicals, Inc.
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Contact-free inactivation of Candida albicans biofilms by cold atmospheric air plasma.
Maisch, Tim; Shimizu, Tetsuji; Isbary, Georg; Heinlin, Julia; Karrer, Sigrid; Klämpfl, Tobias G; Li, Yang-Fang; Morfill, Gregor; Zimmermann, Julia L
2012-06-01
Candida albicans is one of the main species able to form a biofilm on almost any surface, causing both skin and superficial mucosal infections. The worldwide increase in antifungal resistance has led to a decrease in the efficacy of standard therapies, prolonging treatment time and increasing health care costs. Therefore, the aim of this work was to demonstrate the applicability of atmospheric plasma at room temperature for inactivating C. albicans growing in biofilms without thermally damaging heat-sensitive materials. This so-called cold atmospheric plasma is produced by applying high voltage to accelerate electrons, which ionize the surrounding air, leading to the production of charged particles, reactive species, and photons. A newly developed plasma device was used, which exhibits a large plasma-generating surface area of 9 by 13 cm (117 cm(2)). Different time points were selected to achieve an optimum inactivation efficacy range of ≥3 log(10) to 5 log(10) reduction in CFU per milliliter, and the results were compared with those of 70% ethanol. The results obtained show that contact-free antifungal inactivation of Candida biofilms by cold atmospheric plasma is a promising tool for disinfection of surfaces (and items) in both health care settings and the food industry, where ethanol disinfection should be avoided.
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Contact-Free Inactivation of Candida albicans Biofilms by Cold Atmospheric Air Plasma
Shimizu, Tetsuji; Isbary, Georg; Heinlin, Julia; Karrer, Sigrid; Klämpfl, Tobias G.; Li, Yang-Fang; Morfill, Gregor; Zimmermann, Julia L.
2012-01-01
Candida albicans is one of the main species able to form a biofilm on almost any surface, causing both skin and superficial mucosal infections. The worldwide increase in antifungal resistance has led to a decrease in the efficacy of standard therapies, prolonging treatment time and increasing health care costs. Therefore, the aim of this work was to demonstrate the applicability of atmospheric plasma at room temperature for inactivating C. albicans growing in biofilms without thermally damaging heat-sensitive materials. This so-called cold atmospheric plasma is produced by applying high voltage to accelerate electrons, which ionize the surrounding air, leading to the production of charged particles, reactive species, and photons. A newly developed plasma device was used, which exhibits a large plasma-generating surface area of 9 by 13 cm (117 cm2). Different time points were selected to achieve an optimum inactivation efficacy range of ≥3 log10 to 5 log10 reduction in CFU per milliliter, and the results were compared with those of 70% ethanol. The results obtained show that contact-free antifungal inactivation of Candida biofilms by cold atmospheric plasma is a promising tool for disinfection of surfaces (and items) in both health care settings and the food industry, where ethanol disinfection should be avoided. PMID:22467505
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Lara, Humberto H; Guisbiers, Gregory; Mendoza, Jonathan; Mimun, Lawrence C; Vincent, Brandy A; Lopez-Ribot, Jose L; Nash, Kelly L
2018-01-01
Candida albicans is a major opportunistic fungal pathogen. One of the most important virulence factors that contribute to the pathogenesis of candidiasis is its ability to form biofilms. A key characteristic of Candida biofilms is their resistance to antifungal agents. Due to significant morbidity and mortality rates related to biofilm-associated drug resistance, there is an urgency to develop novel nanotechnology-based approaches preventing biofilm-related infections. In this study, we report, for the first time, the synthesis of selenium nanoparticles by irradiating selenium pellets by nanosecond pulsed laser ablation in liquid chitosan as a capping agent. Synergy of the fungicidal effect of selenium nanoparticles and chitosan was quantified by the combination index theorem of Chou-Talalay. This drug combination resulted in a potent fungicidal effect against a preformed C. albicans biofilm in a dose-response manner. By advanced electron microscopy techniques, we documented the adhesive and permeabilizing properties of chitosan, therefore allowing selenium nanoparticles to enter as the cell wall of the yeast became disrupted and distorted. Most importantly, we demonstrated a potent quantitative synergistic effect when compounds such as selenium and chitosan are combined. These chitosan-stabilized selenium nanoparticles could be used for ex vivo applications such as sterilizers for surfaces and biomedical devices.
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Olson, Michelle L; Jayaraman, Arul; Kao, Katy C
2018-04-15
Candida is a member of the normal human microbiota and often resides on mucosal surfaces such as the oral cavity or the gastrointestinal tract. In addition to their commensality, Candida species can opportunistically become pathogenic if the host microbiota is disrupted or if the host immune system becomes compromised. An important factor for Candida pathogenesis is its ability to form biofilm communities. The two most medically important species- Candida albicans and Candida glabrata -are often coisolated from infection sites, suggesting the importance of Candida coculture biofilms. In this work, we report that biofilm formation of the coculture population depends on the relative ratio of starting cell concentrations of C. albicans and C. glabrata When using a starting ratio of C. albicans to C. glabrata of 1:3, ∼6.5- and ∼2.5-fold increases in biofilm biomass were observed relative to those of a C. albicans monoculture and a C. albicans / C. glabrata ratio of 1:1, respectively. Confocal microscopy analysis revealed the heterogeneity and complex structures composed of long C. albicans hyphae and C. glabrata cell clusters in the coculture biofilms, and reverse transcription-quantitative PCR (qRT-PCR) studies showed increases in the relative expression of the HWP1 and ALS3 adhesion genes in the C. albicans / C. glabrata 1:3 biofilm compared to that in the C. albicans monoculture biofilm. Additionally, only the 1:3 C. albicans / C. glabrata biofilm demonstrated an increased resistance to the antifungal drug caspofungin. Overall, the results suggest that interspecific interactions between these two fungal pathogens increase biofilm formation and virulence-related gene expression in a coculture composition-dependent manner. IMPORTANCE Candida albicans and Candida glabrata are often coisolated during infection, and the occurrence of coisolation increases with increasing inflammation, suggesting possible synergistic interactions between the two Candida species in
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Silver Nanoparticles Impact Biofilm Communities and Mussel Settlement
Yang, Jin-Long; Li, Yi-Feng; Liang, Xiao; Guo, Xing-Pan; Ding, De-Wen; Zhang, Demin; Zhou, Shuxue; Bao, Wei-Yang; Bellou, Nikoleta; Dobretsov, Sergey
2016-01-01
Silver nanoparticles (AgNPs) demonstrating good antimicrobial activity are widely used in many fields. However, the impact of AgNPs on the community structures of marine biofilms that drive biogeochemical cycling processes and the recruitment of marine invertebrate larvae remains unknown. Here, we employed MiSeq sequencing technology to evaluate the bacterial communities of 28-day-old marine biofilms formed on glass, polydimethylsiloxane (PDMS), and PDMS filled with AgNPs and subsequently tested the influence of these marine biofilms on plantigrade settlement by the mussel Mytilus coruscus. AgNP-filled PDMS significantly reduced the dry weight and bacterial density of biofilms compared with the glass and PDMS controls. AgNP incorporation impacted bacterial communities by reducing the relative abundance of Flavobacteriaceae (phylum: Bacteroidetes) and increasing the relative abundance of Vibrionaceae (phylum: Proteobacteria) in 28-day-old biofilms compared to PDMS. The settlement rate of M. coruscus on 28-day-old biofilms developed on AgNPs was lower by >30% compared to settlement on control biofilms. Thus, the incorporation of AgNPs influences biofilm bacterial communities in the marine environment and subsequently inhibits mussel settlement. PMID:27869180
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PqsA Promotes Pyoverdine Production via Biofilm Formation
Turner, Kelly E.
2017-01-01
Biofilms create an impermeable barrier against antimicrobial treatment and immune cell access, severely complicating treatment and clearance of nosocomial Pseudomonas aeruginosa infections. We recently reported that biofilm also contributes to pathogen virulence by regulating the production of the siderophore pyoverdine. In this study, we investigated the role of PqsA, a key cell-signaling protein, in this regulatory pathway. We demonstrate that PqsA promotes pyoverdine production in a biofilm-dependent manner. Under nutritionally deficient conditions, where biofilm and pyoverdine are decoupled, PqsA is dispensable for pyoverdine production. Interestingly, although PqsA-dependent pyoverdine production does not rely upon Pseudomonas quinolone signal (PQS) biosynthesis, exogenous PQS can also trigger biofilm-independent production of pyoverdine. Adding PQS rapidly induced planktonic cell aggregation. Moreover, these clumps of cells exhibit strong expression of pyoverdine biosynthetic genes and show substantial production of this siderophore. Finally, we surveyed the relationship between biofilm formation and pyoverdine production in various clinical and environmental isolates of P. aeruginosa to evaluate the clinical significance of targeting biofilm during infections. Our findings implicate PqsA in P. aeruginosa virulence by regulating biofilm formation and pyoverdine production. PMID:29295589
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Modeling biofilms with dual extracellular electron transfer mechanisms
DOE Office of Scientific and Technical Information (OSTI.GOV)
Renslow, Ryan S.; Babauta, Jerome T.; Kuprat, Andrew P.
2013-11-28
Electrochemically active biofilms have a unique form of respiration in which they utilize solid external materials as their terminal electron acceptor for metabolism. Currently, two primary mechanisms have been identified for long-range extracellular electron transfer (EET): a diffusion- and a conduction-based mechanism. Evidence in the literature suggests that some biofilms, particularly Shewanella oneidensis, produce components requisite for both mechanisms. In this study, a generic model is presented that incorporates both diffusion- and conduction-based mechanisms and allows electrochemically active biofilms to utilize both simultaneously. The model was applied to Shewanella oneidensis and Geobacter sulfurreducens biofilms using experimentally generated data found themore » literature. Our simulation results showed that 1) biofilms having both mechanisms available, especially if they can interact, may have metabolic advantage over biofilms that can use only a single mechanism; 2) the thickness of Geobacter sulfurreducens biofilms is likely not limited by conductivity; 3) accurate intrabiofilm diffusion coefficient values are critical for current generation predictions; and 4) the local biofilm potential and redox potential are two distinct measurements and cannot be assumed to have identical values. Finally, we determined that cyclic and squarewave voltammetry are currently not good tools to determine the specific percentage of extracellular electron transfer mechanisms used by biofilms. The developed model will be a critical tool in designing experiments to explain EET mechanisms.« less
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Shirazi, Fazal; Ferreira, Jose A. G.; Stevens, David A.; Clemons, Karl V.; Kontoyiannis, Dimitrios P.
2016-01-01
Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) colonize cystic fibrosis (CF) patient airways. Pa culture filtrates inhibit Af biofilms, and Pa non-CF, mucoid (Muc-CF) and nonmucoid CF (NMuc-CF) isolates form an ascending inhibitory hierarchy. We hypothesized this activity is mediated through apoptosis induction. One Af and three Pa (non-CF, Muc-CF, NMuc-CF) reference isolates were studied. Af biofilm was formed in 96 well plates for 16 h ± Pa biofilm filtrates. After 24 h, apoptosis was characterized by viability dye DiBAc, reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, DNA fragmentation and metacaspase activity. Muc-CF and NMuc-CF filtrates inhibited and damaged Af biofilm (p<0.0001). Intracellular ROS levels were elevated (p<0.001) in NMuc-CF-treated Af biofilms (3.7- fold) compared to treatment with filtrates from Muc-CF- (2.5- fold) or non-CF Pa (1.7- fold). Depolarization of mitochondrial potential was greater upon exposure to NMuc-CF (2.4-fold) compared to Muc-CF (1.8-fold) or non-CF (1.25-fold) (p<0.0001) filtrates. Exposure to filtrates resulted in more DNA fragmentation in Af biofilm, compared to control, mediated by metacaspase activation. In conclusion, filtrates from CF-Pa isolates were more inhibitory against Af biofilms than from non-CF. The apoptotic effect involves mitochondrial membrane damage associated with metacaspase activation. PMID:26930399
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Shirazi, Fazal; Ferreira, Jose A G; Stevens, David A; Clemons, Karl V; Kontoyiannis, Dimitrios P
2016-01-01
Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) colonize cystic fibrosis (CF) patient airways. Pa culture filtrates inhibit Af biofilms, and Pa non-CF, mucoid (Muc-CF) and nonmucoid CF (NMuc-CF) isolates form an ascending inhibitory hierarchy. We hypothesized this activity is mediated through apoptosis induction. One Af and three Pa (non-CF, Muc-CF, NMuc-CF) reference isolates were studied. Af biofilm was formed in 96 well plates for 16 h ± Pa biofilm filtrates. After 24 h, apoptosis was characterized by viability dye DiBAc, reactive oxygen species (ROS) generation, mitochondrial membrane depolarization, DNA fragmentation and metacaspase activity. Muc-CF and NMuc-CF filtrates inhibited and damaged Af biofilm (p<0.0001). Intracellular ROS levels were elevated (p<0.001) in NMuc-CF-treated Af biofilms (3.7- fold) compared to treatment with filtrates from Muc-CF- (2.5- fold) or non-CF Pa (1.7- fold). Depolarization of mitochondrial potential was greater upon exposure to NMuc-CF (2.4-fold) compared to Muc-CF (1.8-fold) or non-CF (1.25-fold) (p<0.0001) filtrates. Exposure to filtrates resulted in more DNA fragmentation in Af biofilm, compared to control, mediated by metacaspase activation. In conclusion, filtrates from CF-Pa isolates were more inhibitory against Af biofilms than from non-CF. The apoptotic effect involves mitochondrial membrane damage associated with metacaspase activation.
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Fox, Emily P; Cowley, Elise S; Nobile, Clarissa J; Hartooni, Nairi; Newman, Dianne K; Johnson, Alexander D
2014-10-20
The human microbiome contains diverse microorganisms, which share and compete for the same environmental niches. A major microbial growth form in the human body is the biofilm state, where tightly packed bacterial, archaeal, and fungal cells must cooperate and/or compete for resources in order to survive. We examined mixed biofilms composed of the major fungal species of the gut microbiome, Candida albicans, and each of five prevalent bacterial gastrointestinal inhabitants: Bacteroides fragilis, Clostridium perfringens, Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecalis. We observed that biofilms formed by C. albicans provide a hypoxic microenvironment that supports the growth of two anaerobic bacteria, even when cultured in ambient oxic conditions that are normally toxic to the bacteria. We also found that coculture with bacteria in biofilms induces massive gene expression changes in C. albicans, including upregulation of WOR1, which encodes a transcription regulator that controls a phenotypic switch in C. albicans, from the "white" cell type to the "opaque" cell type. Finally, we observed that in suspension cultures, C. perfringens induces aggregation of C. albicans into "mini-biofilms," which allow C. perfringens cells to survive in a normally toxic environment. This work indicates that bacteria and C. albicans interactions modulate the local chemistry of their environment in multiple ways to create niches favorable to their growth and survival. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Candida albicans biofilms: development, regulation, and molecular mechanisms
Gulati, Megha; Nobile, Clarissa J.
2016-01-01
A major virulence attribute of Candida albicans is its ability to form biofilms, densely packed communities of cells adhered to a surface. These biofilms are intrinsically resistant to conventional antifungal therapeutics, the host immune system, and other environmental factors, making biofilm-associated infections a significant clinical challenge. Here, we review current knowledge on the development, regulation, and molecular mechanisms of C. albicans biofilms. PMID:26806384
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Evidence for biofilm acid neutralization by baking soda.
Zero, Domenick T
2017-11-01
The generating of acids from the microbial metabolism of dietary sugars and the subsequent decrease in biofilm pH below the pH at which tooth mineral begins to demineralize (critical pH) are the key elements of the dental caries process. Caries preventive strategies that rapidly neutralize biofilm acids can prevent demineralization and favor remineralization and may help prevent the development of sugar-induced dysbiosis that shifts the biofilm toward increased cariogenic potential. Although the neutralizing ability of sodium bicarbonate (baking soda) has been known for many years, its anticaries potential as an additive to fluoride dentifrice has received only limited investigation. There is evidence that baking soda rapidly can reverse the biofilm pH decrease after a sugar challenge; however, the timing of when it is used in relation to a dietary sugar exposure is critical in that the sooner its used the greater the benefit in preventing a sustained biofilm pH decrease and subsequent demineralization. Furthermore, the effectiveness of baking soda in elevating biofilm pH appears to depend on concentration. Thus, the concentration of baking soda in marketed dentifrice products, which ranges from 10% to 65%, may affect their biofilm pH neutralizing performance. People with hyposalivation particularly may benefit from using fluoride dentifrice containing baking soda because of their diminished ability to clear dietary sugars and buffer biofilm acids. Although promising, there is the need for more evidence that strategies that modify the oral ecology, such as baking soda, can alter the cariogenic (acidogenic and aciduric) properties of biofilm microorganisms. The acid neutralization of dental biofilm by using fluoride dentifrice that contains baking soda has potential for helping counteract modern high-sugar diets by rapidly neutralizing biofilm-generated acid, especially in people with hyposalivation. Copyright © 2017 American Dental Association. Published by
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Shirazi, F; Kontoyiannis, DP
2015-01-01
Candida biofilms play an important role in infections associated with medical devices and are resistant to antifungals. We hypothesized that the echinocandin micafungin (MICA) exerts an enhanced antifungal activity against caspofungin (CAS)-susceptible (CAS-S) and CAS–non-susceptible (CAS-NS) Candida albicans and Candida parapsilosis which is at least in part through apoptosis, even in the biofilm environment. Apoptosis was characterized by detecting reactive oxygen species (ROS) accumulation, depolarization of mitochondrial membrane potential (MMP), DNA fragmentation, lack of plasma membrane integrity, and metacaspase activation following exposure of Candida biofilm to MICA for 3h at 37°C in RPMI 1640 medium. The minimum inhibitory concentration was higher for CAS (2.0–16.0 μg/mL) than for MICA (1.0–8.0 μg/mL) for Candida biofilms. Elevated intracellular ROS levels and depolarization of MMP was evident in CAS-S C. albicans (3.0–4.2 fold) and C. parapsilosis (4.8–5.4 fold) biofilms compared with CAS-NS (1.2 fold) after exposure to MICA (0.25x-1xMIC). Elevated intracellular ROS levels and depolarization of MMP was evident in CAS-S C. albicans (3.0–4.2 fold) and C. parapsilosis (4.8–5.4 fold) biofilms compared with CAS-NS (1.2 fold) after exposure to MICA (0.25x-1xMIC). Finally higher ß-1, 3 glucan levels were seen in sessile cells compared to planktonic cells, especially in CAS-NS strains. MICA treatment might induce a metacaspase-dependent apoptotic process in biofilms of both CAS-S C. albicans and C. parapsilosis, and to some degree in CAS-NS strains. PMID:26065323
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Jeon, Hye Ri; Kwon, Mi Jin; Yoon, Ki Sun
2018-04-01
Biofilm formation on food contact surfaces is a potential hazard leading to cross-contamination during food processing. We investigated Listeria innocua biofilm formation on various food contact surfaces and compared the washing effect of slightly acidic electrolyzed water (SAEW) at 30, 50, 70, and 120 ppm with that of 200 ppm of sodium hypochlorite (NaClO) on biofilm cells. The risk of L. innocua biofilm transfer and growth on food at retail markets was also investigated. The viability of biofilms that formed on food contact surfaces and then transferred cells to duck meat was confirmed by fluorescence microscopy. L. innocua biofilm formation was greatest on rubber, followed by polypropylene, glass, and stainless steel. Regardless of sanitizer type, washing removed biofilms from polypropylene and stainless steel better than from rubber and glass. Among the various SAEW concentrations, washing with 70 ppm of SAEW for 5 min significantly reduced L. innocua biofilms on food contact surfaces during food processing. Efficiency of transfer of L. innocua biofilm cells was the highest on polypropylene and lowest on stainless steel. The transferred biofilm cells grew to the maximum population density, and the lag time of transferred biofilm cells was longer than that of planktonic cells. The biofilm cells that transferred to duck meat coexisted with live, injured, and dead cells, which indicates that effective washing is essential to remove biofilm on food contact surfaces during food processing to reduce the risk of foodborne disease outbreaks.
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Hsu, Sze-Bi; Yang, Ya-Tang
2016-04-01
We present the theory of a microfluidic bioreactor with a two-compartment growth chamber and periodic serial dilution. In the model, coexisting planktonic and biofilm populations exchange by adsorption and detachment. The criteria for coexistence and global extinction are determined by stability analysis of the global extinction state. Stability analysis yields the operating diagram in terms of the dilution and removal ratios, constrained by the plumbing action of the bioreactor. The special case of equal uptake function and logistic growth is analytically solved and explicit growth curves are plotted. The presented theory is applicable to generic microfluidic bioreactors with discrete growth chambers and periodic dilution at discrete time points. Therefore, the theory is expected to assist the design of microfluidic devices for investigating microbial competition and microbial biofilm growth under serial dilution conditions.
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Development of a high-throughput Candida albicans biofilm chip.
Srinivasan, Anand; Uppuluri, Priya; Lopez-Ribot, Jose; Ramasubramanian, Anand K
2011-04-22
We have developed a high-density microarray platform consisting of nano-biofilms of Candida albicans. A robotic microarrayer was used to print yeast cells of C. albicans encapsulated in a collagen matrix at a volume as low as 50 nL onto surface-modified microscope slides. Upon incubation, the cells grow into fully formed "nano-biofilms". The morphological and architectural complexity of these biofilms were evaluated by scanning electron and confocal scanning laser microscopy. The extent of biofilm formation was determined using a microarray scanner from changes in fluorescence intensities due to FUN 1 metabolic processing. This staining technique was also adapted for antifungal susceptibility testing, which demonstrated that, similar to regular biofilms, cells within the on-chip biofilms displayed elevated levels of resistance against antifungal agents (fluconazole and amphotericin B). Thus, results from structural analyses and antifungal susceptibility testing indicated that despite miniaturization, these biofilms display the typical phenotypic properties associated with the biofilm mode of growth. In its final format, the C. albicans biofilm chip (CaBChip) is composed of 768 equivalent and spatially distinct nano-biofilms on a single slide; multiple chips can be printed and processed simultaneously. Compared to current methods for the formation of microbial biofilms, namely the 96-well microtiter plate model, this fungal biofilm chip has advantages in terms of miniaturization and automation, which combine to cut reagent use and analysis time, minimize labor intensive steps, and dramatically reduce assay costs. Such a chip should accelerate the antifungal drug discovery process by enabling rapid, convenient and inexpensive screening of hundreds-to-thousands of compounds simultaneously.
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Functional Relationship between Sucrose and a Cariogenic Biofilm Formation
Cai, Jian-Na; Jung, Ji-Eun; Dang, Minh-Huy; Kim, Mi-Ah; Yi, Ho-Keun; Jeon, Jae-Gyu
2016-01-01
Sucrose is an important dietary factor in cariogenic biofilm formation and subsequent initiation of dental caries. This study investigated the functional relationships between sucrose concentration and Streptococcus mutans adherence and biofilm formation. Changes in morphological characteristics of the biofilms with increasing sucrose concentration were also evaluated. S. mutans biofilms were formed on saliva-coated hydroxyapatite discs in culture medium containing 0, 0.05, 0.1, 0.5, 1, 2, 5, 10, 20, or 40% (w/v) sucrose. The adherence (in 4-hour biofilms) and biofilm composition (in 46-hour biofilms) of the biofilms were analyzed using microbiological, biochemical, laser scanning confocal fluorescence microscopic, and scanning electron microscopic methods. To determine the relationships, 2nd order polynomial curve fitting was performed. In this study, the influence of sucrose on bacterial adhesion, biofilm composition (dry weight, bacterial counts, and water-insoluble extracellular polysaccharide (EPS) content), and acidogenicity followed a 2nd order polynomial curve with concentration dependence, and the maximum effective concentrations (MECs) of sucrose ranged from 0.45 to 2.4%. The bacterial and EPS bio-volume and thickness in the biofilms also gradually increased and then decreased as sucrose concentration increased. Furthermore, the size and shape of the micro-colonies of the biofilms depended on the sucrose concentration. Around the MECs, the micro-colonies were bigger and more homogeneous than those at 0 and 40%, and were surrounded by enough EPSs to support their structure. These results suggest that the relationship between sucrose concentration and cariogenic biofilm formation in the oral cavity could be described by a functional relationship. PMID:27275603
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Dynamic remodeling of microbial biofilms by functionally distinct exopolysaccharides.
Chew, Su Chuen; Kundukad, Binu; Seviour, Thomas; van der Maarel, Johan R C; Yang, Liang; Rice, Scott A; Doyle, Patrick; Kjelleberg, Staffan
2014-08-05
Biofilms are densely populated communities of microbial cells protected and held together by a matrix of extracellular polymeric substances. The structure and rheological properties of the matrix at the microscale influence the retention and transport of molecules and cells in the biofilm, thereby dictating population and community behavior. Despite its importance, quantitative descriptions of the matrix microstructure and microrheology are limited. Here, particle-tracking microrheology in combination with genetic approaches was used to spatially and temporally study the rheological contributions of the major exopolysaccharides Pel and Psl in Pseudomonas aeruginosa biofilms. Psl increased the elasticity and effective cross-linking within the matrix, which strengthened its scaffold and appeared to facilitate the formation of microcolonies. Conversely, Pel reduced effective cross-linking within the matrix. Without Psl, the matrix becomes more viscous, which facilitates biofilm spreading. The wild-type biofilm decreased in effective cross-linking over time, which would be advantageous for the spreading and colonization of new surfaces. This suggests that there are regulatory mechanisms to control production of the exopolysaccharides that serve to remodel the matrix of developing biofilms. The exopolysaccharides were also found to have profound effects on the spatial organization and integration of P. aeruginosa in a mixed-species biofilm model of P. aeruginosa-Staphylococcus aureus. Pel was required for close association of the two species in mixed-species microcolonies. In contrast, Psl was important for P. aeruginosa to form single-species biofilms on top of S. aureus biofilms. Our results demonstrate that Pel and Psl have distinct physical properties and functional roles during biofilm formation. Importance: Most bacteria grow as biofilms in the environment or in association with eukaryotic hosts. Removal of biofilms that form on surfaces is a challenge in clinical
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Effect of Infant Formula on Streptococcus Mutans Biofilm Formation.
Hinds, Laura M; Moser, Elizabeth A S; Eckert, George; Gregory, Richard L
This study investigated the effect that infant formula had on biofilm growth of Streptococcus mutans. Specifically, it compared biofilm growth in media containing lactose-based and sucrose-based formulas. It also analyzed biofilm formation with formulas of varying iron content. Biofilm growth was tested with the specific infant formula components sucrose, lactose, and ferric chloride. The study was designed to determine if these types of infant formulas and components affected S. mutans biofilm formation differently. A 24-hour culture of S. mutans was treated with various concentrations of infant formula diluted in bacteriological media. To test for biofilm formation, S. mutans was cultured with and without the infant formula and formula components. The biofilms were washed, fixed, and stained with crystal violet. The absorbance was measured to evaluate biofilm growth and total absorbance. Sucrose-based formulas provided significant increases in biofilm growth when compared to lactose-based formulas at two dilutions (1:5, 1:20). Similac Sensitive RS (sucrose-based) at most dilutions provided the most significant increase in biofilm growth when compared to the control. Sucrose tested as an individual component provided more of a significant increase on biofilm growth than lactose or iron when compared to the control. A low iron formula provided a significant increase in biofilm growth at one dilution (1:5) when compared to formula containing a normal iron content. There was no significant difference in biofilm growth when comparing high iron formula to normal iron formula or low iron formula. There was no significant difference when comparing Similac PM 60/40 (low iron formula) to Similac PM 60/40 with additional ferric chloride. The results of this study demonstrated that sucrose-based formula provided more of a significant increase in biofilm growth compared to lactose-based formula. Sucrose alone provided a significant increase of biofilm growth at more dilutions
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Biofilm disruption with rotating microrods enhances antimicrobial efficacy
NASA Astrophysics Data System (ADS)
Mair, Lamar O.; Nacev, Aleksandar; Hilaman, Ryan; Stepanov, Pavel Y.; Chowdhury, Sagar; Jafari, Sahar; Hausfeld, Jeffrey; Karlsson, Amy J.; Shirtliff, Mark E.; Shapiro, Benjamin; Weinberg, Irving N.
2017-04-01
Biofilms are a common and persistent cause of numerous illnesses. Compared to planktonic microbes, biofilm residing cells often demonstrate significant resistance to antimicrobial agents. Thus, methods for dislodging cells from the biofilm may increase the antimicrobial susceptibility of such cells, and serve as a mechanical means of increasing antimicrobial efficacy. Using Aspergillus fumigatus as a model microbe, we magnetically rotate microrods in and around biofilm. We show that such rods can improve the efficacy of antimicrobial Amphotericin B treatments in vitro. This work represents a first step in using kinetic magnetic particle therapy for disrupting fungal biofilms.
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Emerging interactions between matrix components during biofilm development.
Payne, David E; Boles, Blaise R
2016-02-01
Bacterial cells are most often found in the form of multicellular aggregates commonly referred to as biofilms. Biofilms offer their member cells several benefits, such as resistance to killing by antimicrobials and predation. During biofilm formation there is a production of extracellular substances that, upon assembly, constitute an extracellular matrix. The ability to generate a matrix encasing the microbial cells is a common feature of biofilms, but there is diversity in matrix composition and in interaction between matrix components. The different components of bacterial biofilm extracellular matrixes, known as matrix interactions, and resulting implications are discussed in this review.
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The effect of PDT on H. influenzae biofilm in vitro
NASA Astrophysics Data System (ADS)
Rhee, C.-K.; Bae, S. H.; Lee, J. W.; Ahn, J. C.; Jung, J. Y.; Suh, M.-W.
2009-02-01
Biofilm formation has been demonstrated for many mucosal pathogens such as Haemophilus influenzae. The presence of mucosal biofilms with chronic otitis media with effusion (COME) suggests that bacteria do not clear by antibiotics. Aim: To test the effect of photodynamic therapy (PDT) on H. influenzae biofilm in vitro. Methods: Sixteen biofilms of H. influenzae were maintained on culture chamber with continuous flow cell system. The biofilms were divided into control, laser, photofrin, and PDT groups. For culture group, the biofilms were cultured. For laser group, 7.2 J/cm2 of 632 nm diode laser was irradiated to the biofilms. For photofrin group, photofrins 5 and 25ug/ml were added to the media. For PDT group, photofrins 5 and 25 ug/ml were added to the media following 632 nm diode laser was irradiated (7.2 J/cm2) to the biofilms. Live/Dead (DAPI/PI) stain was performed and biofilms were examined under confocal laser microscope for thickness and density of biofilms. Results: By DAPI/PI staining, significant reduction of biofilms thickness and complete killing of H. influenzae in PDT group with 25µg photofrin was noted while the biofilms were well maintained in the other groups. Conclusion: The results of this study demonstrated that PDT appears to be effective to photoinactivate experimental H. influenzae biofilms in vitro. Clinical implication: PDT can be a possible alternative treatment to antiobiotic treatment on otitis media with biofilm formation.
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Di Domenico, Enea G.; Toma, Luigi; Provot, Christian; Ascenzioni, Fiorentina; Sperduti, Isabella; Prignano, Grazia; Gallo, Maria T.; Pimpinelli, Fulvia; Bordignon, Valentina; Bernardi, Thierry; Ensoli, Fabrizio
2016-01-01
Microbial biofilm represents a major virulence factor associated with chronic and recurrent infections. Pathogenic bacteria embedded in biofilms are highly resistant to environmental and chemical agents, including antibiotics and therefore difficult to eradicate. Thus, reliable tests to assess biofilm formation by bacterial strains as well as the impact of chemicals or antibiotics on biofilm formation represent desirable tools for a most effective therapeutic management and microbiological risk control. Current methods to evaluate biofilm formation are usually time-consuming, costly, and hardly applicable in the clinical setting. The aim of the present study was to develop and assess a simple and reliable in vitro procedure for the characterization of biofilm-producing bacterial strains for future clinical applications based on the BioFilm Ring Test® (BRT) technology. The procedure developed for clinical testing (cBRT) can provide an accurate and timely (5 h) measurement of biofilm formation for the most common pathogenic bacteria seen in clinical practice. The results gathered by the cBRT assay were in agreement with the traditional crystal violet (CV) staining test, according to the κ coefficient test (κ = 0.623). However, the cBRT assay showed higher levels of specificity (92.2%) and accuracy (88.1%) as compared to CV. The results indicate that this procedure offers an easy, rapid and robust assay to test microbial biofilm and a promising tool for clinical microbiology. PMID:27708625
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Agriculturally important microbial biofilms: Present status and future prospects.
Velmourougane, Kulandaivelu; Prasanna, Radha; Saxena, Anil Kumar
2017-07-01
Microbial biofilms are a fascinating subject, due to their significant roles in the environment, industry, and health. Advances in biochemical and molecular techniques have helped in enhancing our understanding of biofilm structure and development. In the past, research on biofilms primarily focussed on health and industrial sectors; however, lately, biofilms in agriculture are gaining attention due to their immense potential in crop production, protection, and improvement. Biofilms play an important role in colonization of surfaces - soil, roots, or shoots of plants and enable proliferation in the desired niche, besides enhancing soil fertility. Although reports are available on microbial biofilms in general; scanty information is published on biofilm formation by agriculturally important microorganisms (bacteria, fungi, bacterial-fungal) and their interactions in the ecosystem. Better understanding of agriculturally important bacterial-fungal communities and their interactions can have several implications on climate change, soil quality, plant nutrition, plant protection, bioremediation, etc. Understanding the factors and genes involved in biofilm formation will help to develop more effective strategies for sustainable and environment-friendly agriculture. The present review brings together fundamental aspects of biofilms, in relation to their formation, regulatory mechanisms, genes involved, and their application in different fields, with special emphasis on agriculturally important microbial biofilms. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Interaction of Nanoparticles with Biofilms
In this work we have studied the interaction and adsorption of engineered nanoparticles such as TiO2, ZnO, CeO2 , and carbon nanotubes with biofilms. Biofilm is an extracellular polymeric substance coating comprised of living material and it is an aggregation of bacteria, algae, ...
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Biofilm on dental implants: a review of the literature.
Subramani, Karthikeyan; Jung, Ronald E; Molenberg, Aart; Hammerle, Christoph H F
2009-01-01
The aim of this article was to review the current literature with regard to biofilm formation on dental implants and the influence of surface characteristics (chemistry, surface free energy, and roughness) of dental implant and abutment materials and their design features on biofilm formation and its sequelae. An electronic MEDLINE literature search was conducted of studies published between 1966 and June 2007. The following search terms were used: biofilm and dental implants, biofilm formation/plaque bacterial adhesion and implants, plaque/biofilm and surface characteristics/roughness/surface free energy of titanium dental implants, implant-abutment interface and plaque/biofilm, biofilm and supragingival/subgingival plaque microbiology, biofilm/plaque and implant infection, antibacterial/bacteriostatic titanium, titanium nanocoating/nanopatterning, antimicrobial drug/titanium implant. Both in vitro and in vivo studies were included in this review. Fifty-three articles were identified in this review process. The articles were categorized with respect to their context on biofilm formation on teeth and dental implant surfaces and with regard to the influence of surface characteristics of implant biomaterials (especially titanium) and design features of implant and abutment components on biofilm formation. The current state of literature is more descriptive, rather than providing strong data that could be analyzed through meta-analysis. Basic research articles on surface modification of titanium were also included in the review to analyze the applications of such studies on the fabrication of implant surfaces that could possibly decrease early bacterial colonization and biofilm formation. Increase in surface roughness and surface free energy facilitates biofilm formation on dental implant and abutment surfaces, although this conclusion is derived from largely descriptive literature. Surface chemistry and the design features of the implant-abutment configuration also