Sample records for damages fungal biofilms
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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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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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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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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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A confocal microscopy based method to monitor extracellular pH in fungal biofilms.
Schlafer, Sebastian; Kamp, Anja; Garcia, Javier E
2018-04-19
pH in fungal biofilms is important for a variety of fungal infections and industrial applications involving fungal biofilms, but to date, it has never been measured directly inside the biofilm matrix. In the present study, a new methodology was developed allowing for confocal microscopy based monitoring of extracellular pH inside fungal biofilms. Monospecies biofilms of Aspergillus fumigatus, Candida albicans, Candida dubliniensis and Cryptococcus neoformans were stained with the pH dependent ratiometric probe C-SNARF-4, imaged with a confocal microscope, and a digital image analysis procedure was developed to determine pH in the extracellular matrix. As a proof of concept, pH developments at the biofilm-substratum interface were monitored for one h after exposure to glucose. Observed pH drops differed considerably between the different species and also between replicate biofilms of the same species. C. albicans biofilms showed the highest acidogenicity, with pH drops occurring much faster than in planktonic culture. pH ratiometry with C-SNARF-4 is a valuable tool to get insight into fungal biofilm metabolism and may shed new light on both disease-related and industrially relevant processes in fungal biofilms.
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From Biology to Drug Development: New Approaches to Combat the Threat of Fungal Biofilms
Pierce, Christopher G.; Srinivasan, Anand; Ramasubramanian, Anand K.; López-Ribot, José L.
2015-01-01
Fungal infections constitute a major threat to an escalating number of critically ill patients. Fungi are eukaryotic organisms and, as such, there is a limited armamentarium of antifungal drugs, leading to high mortality rates. Moreover, fungal infections are often associated with the formation of biofilms, which contribute to virulence and further complicate treatment due to the high level of antifungal drug resistance displayed by sessile cells within these microbial communities. Thus, the treatment of fungal infections associated with a biofilm aetiology represents a formidable and unmet clinical challenge. The increasing importance and awareness of fungal biofilms is reflected by the fact that this is now an area of very active research. Studies in the last decade have provided important insights into fungal biofilm biology, physiology and pathology, as well as into the molecular basis of biofilm resistance. Here we discuss how this accumulated knowledge may inform the development of new anti-biofilm strategies and therapeutics that are urgently needed. PMID:26185082
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Effects of lactoferricin B against keratitis-associated fungal biofilms.
Sengupta, Jayangshu; Saha, Suman; Khetan, Archana; Sarkar, Sujoy K; Mandal, Santi M
2012-10-01
Biofilms are considered as the most important developmental characteristics in ocular infections. Biofilm eradication is a major challenge today to overcome the incidence of drug resistance. This report demonstrates the in vitro ability of biofilm formation on contact lens by three common keratitis-associated fungal pathogens, namely, Aspergillus fumigatus, Fusarium solani, and Candida albicans. Antifungal sensitivity testing performed for both planktonic cells and biofilm revealed the sessile phenotype to be resistant at MIC levels for the planktonic cells and also at higher concentrations. A prototype lens care solution was also found to be partially effective in eradication of the mature biofilm from contact lenses. Lactoferricin B (Lacf, 64 μg/ml), an antimicrobial peptide, exhibited almost no effect on the sessile phenotype. However, the combinatory effect of Lacf with antifungals against planktonic cells and biofilms of three fungal strains that were isolated from keratitis patients exhibited a reduction of antifungal dose more than eightfold. Furthermore, the effect of Lacf in lens care solution against biofilms in which those strains formed was eradicated successfully. These results suggest that lactoferricin B could be a promising candidate for clinical use in improving biofilm susceptibility to antifungals and also as an antibiofilm-antifungal additive in lens care solution.
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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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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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DOE Office of Scientific and Technical Information (OSTI.GOV)
Miquel Guennoc, Cora; Rose, Christophe; Guinnet, Frédéric
Bacterial biofilms frequently form on fungal surfaces and can be involved in numerous bacterial-fungal interaction processes, such as metabolic cooperation, competition, or predation. The study of biofilms is important in many biological fields, including environmental science, food production, and medicine. However, few studies have focused on such bacterial biofilms, partially due to the difficulty of investigating them. Most of the methods for qualitative and quantitative biofilm analyses described in the literature are only suitable for biofilms forming on abiotic surfaces or on homogeneous and thin biotic surfaces, such as a monolayer of epithelial cells. While laser scanning confocal microscopy (LSCM)more » is often used to analyze in situ and in vivo biofilms, this technology becomes very challenging when applied to bacterial biofilms on fungal hyphae, due to the thickness and the three dimensions of the hyphal networks. To overcome this shortcoming, we developed a protocol combining microscopy with a method to limit the accumulation of hyphal layers in fungal colonies. Using this method, we were able to investigate the development of bacterial biofilms on fungal hyphae at multiple scales using both LSCM and scanning electron microscopy (SEM). Furthermore, this report describes the protocol, including microorganism cultures, bacterial biofilm formation conditions, biofilm staining, and LSCM and SEM visualizations.« less
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Miquel Guennoc, Cora; Rose, Christophe; Guinnet, Frédéric; ...
2017-01-01
Bacterial biofilms frequently form on fungal surfaces and can be involved in numerous bacterial-fungal interaction processes, such as metabolic cooperation, competition, or predation. The study of biofilms is important in many biological fields, including environmental science, food production, and medicine. However, few studies have focused on such bacterial biofilms, partially due to the difficulty of investigating them. Most of the methods for qualitative and quantitative biofilm analyses described in the literature are only suitable for biofilms forming on abiotic surfaces or on homogeneous and thin biotic surfaces, such as a monolayer of epithelial cells. While laser scanning confocal microscopy (LSCM)more » is often used to analyze in situ and in vivo biofilms, this technology becomes very challenging when applied to bacterial biofilms on fungal hyphae, due to the thickness and the three dimensions of the hyphal networks. To overcome this shortcoming, we developed a protocol combining microscopy with a method to limit the accumulation of hyphal layers in fungal colonies. Using this method, we were able to investigate the development of bacterial biofilms on fungal hyphae at multiple scales using both LSCM and scanning electron microscopy (SEM). Furthermore, this report describes the protocol, including microorganism cultures, bacterial biofilm formation conditions, biofilm staining, and LSCM and SEM visualizations.« less
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Sustained release of a novel anti-quorum-sensing agent against oral fungal biofilms.
Feldman, Mark; Shenderovich, Julia; Al-Quntar, Abed Al Aziz; Friedman, Michael; Steinberg, Doron
2015-04-01
Thiazolidinedione-8 (S-8) has recently been identified as a potential anti-quorum-sensing/antibiofilm agent against bacteria and fungi. Based on these results, we investigated the possibility of incorporating S-8 in a sustained-release membrane (SRM) to increase its pharmaceutical potential against Candida albicans biofilm. We demonstrated that SRM containing S-8 inhibits fungal biofilm formation in a time-dependent manner for 72 h, due to prolonged release of S-8. Moreover, the SRM effectively delivered the agent in its active form to locations outside the membrane reservoir. In addition, eradication of mature biofilm by the SRM containing S-8 was also significant. Of note, S-8-containing SRM affected the characteristics of mature C. albicans biofilm, such as thickness, exopolysaccharide (EPS) production, and morphogenesis of fungal cells. The concept of using an antibiofilm agent with no antifungal activity incorporated into a sustained-release delivery system is new in medicine and dentistry. This concept of an SRM containing a quorum-sensing quencher with an antibiofilm effect could pave the way for combating oral fungal infectious diseases. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
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Sorting of fungal-damaged white sorghum
USDA-ARS?s Scientific Manuscript database
A high-speed, color image-based sorting machine was modified to separate white sorghum with symptoms of fungal damage. Most of the sorghum tested was typically white, but over 27% of the bulk contained grains with fungal damage of various degrees, from severe to very slight. Grains with slight fun...
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Mycoalgae biofilm: development of a novel platform technology using algae and fungal cultures.
Rajendran, Aravindan; Hu, Bo
2016-01-01
Microalgae is considered a promising source for biofuel and bioenergy production, bio-remediation and production of high-value bioactive compounds, but harvesting microalgae is a major bottleneck in the algae based processes. The objective of this research is to mimic the growth of natural lichen and develop a novel biofilm platform technology using filamentous fungi and microalgae to form a lichen type of biofilm "mycoalgae" in a supporting polymer matrix. The possibility of co-existence of Chlorella vulgaris with various fungal cultures was tested to identify the best strain combination for high algae harvest efficiency. The effect of different matrices for cell attachment and biofilm formation, cell surface characterization of mycoalgae biofilm, kinetics of the process with respect to the algae-fungi cell distribution and total biomass production was studied. Mycoalgae biofilm with algae attachment efficiency of 99.0 % and above was achieved in a polymer-cotton composite matrix with glucose concentration of 2 g/L in the growth medium and agitation intensity of 150 rpm at 27 °C. The total biomass in the co-culture with the selected strain combination (Mucor sp. and Chlorella sp.) was higher than the axenic cultures of fungi and algae at the conditions tested. The results show that algae can be grown with complete attachment to a bio-augmenting fungal surface and can be harvested readily as a biofilm for product extraction from biomass. Even though, interaction between heterotrophic fungi and phototrophic algae was investigated in solid media after prolonged contact in a report, this research is the first of its kind in developing an artificial lichen type biofilm called "mycoalgae" biofilm completely attached on a matrix in liquid cultures. The mycoalgae biofilm based processes, propounds the scope for exploring new avenues in the bio-production industry and bioremediation.
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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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Douterelo, I; Fish, K E; Boxall, J B
2018-09-15
Understanding the temporal dynamics of multi-species biofilms in Drinking Water Distribution Systems (DWDS) is essential to ensure safe, high quality water reaches consumers after it passes through these high surface area reactors. This research studied the succession characteristics of fungal and bacterial communities under controlled environmental conditions fully representative of operational DWDS. Microbial communities were observed to increase in complexity after one month of biofilm development but they did not reach stability after three months. Changes in cell numbers were faster at the start of biofilm formation and tended to decrease over time, despite the continuing changes in bacterial community composition. Fungal diversity was markedly less than bacterial diversity and had a lag in responding to temporal dynamics. A core-mixed community of bacteria including Pseudomonas, Massillia and Sphingomonas and the fungi Acremonium and Neocosmopora were present constantly and consistently in the biofilms over time and conditions studied. Monitoring and managing biofilms and such ubiquitous core microbial communities are key control strategies to ensuring the delivery of safe drinking water via the current ageing DWDS infrastructure. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.
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Zune, Q; Delepierre, A; Gofflot, S; Bauwens, J; Twizere, J C; Punt, P J; Francis, F; Toye, D; Bawin, T; Delvigne, F
2015-08-01
Fungal biofilm is known to promote the excretion of secondary metabolites in accordance with solid-state-related physiological mechanisms. This work is based on the comparative analysis of classical submerged fermentation with a fungal biofilm reactor for the production of a Gla::green fluorescent protein (GFP) fusion protein by Aspergillus oryzae. The biofilm reactor comprises a metal structured packing allowing the attachment of the fungal biomass. Since the production of the target protein is under the control of the promoter glaB, specifically induced in solid-state fermentation, the biofilm mode of culture is expected to enhance the global productivity. Although production of the target protein was enhanced by using the biofilm mode of culture, we also found that fusion protein production is also significant when the submerged mode of culture is used. This result is related to high shear stress leading to biomass autolysis and leakage of intracellular fusion protein into the extracellular medium. Moreover, 2-D gel electrophoresis highlights the preservation of fusion protein integrity produced in biofilm conditions. Two fungal biofilm reactor designs were then investigated further, i.e. with full immersion of the packing or with medium recirculation on the packing, and the scale-up potentialities were evaluated. In this context, it has been shown that full immersion of the metal packing in the liquid medium during cultivation allows for a uniform colonization of the packing by the fungal biomass and leads to a better quality of the fusion protein.
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2017-01-01
ABSTRACT Bacteria interact with each other in nature and often compete for limited nutrient and space resources. However, it is largely unknown whether and how bacteria also interact with human fungal pathogens naturally found in the environment. Here, we identified a soil bacterium, Bacillus safensis, which potently blocked several key Cryptococcus neoformans virulence factors, including formation of the antioxidant pigment melanin and production of the antiphagocytic polysaccharide capsule. The bacterium also inhibited de novo cryptococcal biofilm formation but had only modest inhibitory effects on already formed biofilms or planktonic cell growth. The inhibition of fungal melanization was dependent on direct cell contact and live bacteria. B. safensis also had anti-virulence factor activity against another major human-associated fungal pathogen, Candida albicans. Specifically, dual-species interaction studies revealed that the bacterium strongly inhibited C. albicans filamentation and biofilm formation. In particular, B. safensis physically attached to and degraded candidal filaments. Through genetic and phenotypic analyses, we demonstrated that bacterial chitinase activity against fungal cell wall chitin is a factor contributing to the antipathogen effect of B. safensis. PMID:28974618
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Xiros, Charilaos; Studer, Michael H.
2017-01-01
The constraints and advantages in cellulolytic enzymes production by fungal biofilms for a consolidated bioconversion process were investigated during this study. The biofilm cultivations were carried out in reactors designed for consolidated bioprocessing Multispecies Biofilm Membrane reactors, (MBM) where an aerobic fungal biofilm produces the lignocellulolytic enzymes while a fermenting microorganism forms the fermentation product at anaerobic conditions. It was shown that although mycelial growth was limited in the MBM reactors compared to submerged cultivations, the secretion of cellulolytic enzymes per cell dry weight was higher. When Trichoderma reesei was used as the sole enzyme producer, cellobiose accumulated in the liquid medium as the result of the deficiency of β-glucosidase in the fungal secretome. To enhance β-glucosidase activity, T. reesei was co-cultivated with A. phoenicis which is a β-glucosidase overproducer. The two fungi formed a multispecies biofilm which produced a balanced cellulolytic cocktail for the saccharification of plant biomass. The mixed biofilm reached a 2.5 fold increase in β-glucosidase production, compared to the single T. reesei biofilm. The enzymatic systems of single and mixed biofilms were evaluated regarding their efficiency on cellulosic substrates degradation. Washed solids from steam pretreated beechwood, as well as microcrystalline cellulose were used as the substrates. The enzymatic system of the multispecies biofilm released four times more glucose than the enzymatic system of T. reesei alone from both substrates and hydrolyzed 78 and 60% of the cellulose content of washed solids from beechwood and microcrystalline cellulose, respectively. PMID:29067006
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Irrizary, Jihyun; Liboro, Karl; Bogarin, Thania; Macias, Marlene; Eivers, Edward; Porter, Edith; Filler, Scott G.
2017-01-01
The regulatory networks governing morphogenesis of a pleomorphic fungus, Candida albicans are extremely complex and remain to be completely elucidated. This study investigated the function of C. albicans yeast casein kinase 2 (CaYck2p). The yck2Δ/yck2Δ strain displayed constitutive pseudohyphae in both yeast and hyphal growth conditions, and formed enhanced biofilm under non-biofilm inducing condition. This finding was further supported by gene expression analysis of the yck2Δ/yck2Δ strain which showed significant upregulation of UME6, a key transcriptional regulator of hyphal transition and biofilm formation, and cell wall protein genes ALS3, HWP1, and SUN41, all of which are associated with morphogenesis and biofilm architecture. The yck2Δ/yck2Δ strain was hypersensitive to cell wall damaging agents and had increased compensatory chitin deposition in the cell wall accompanied by an upregulation of the expression of the chitin synthase genes, CHS2, CHS3, and CHS8. Absence of CaYck2p also affected fungal-host interaction; the yck2Δ/yck2Δ strain had significantly reduced ability to damage host cells. However, the yck2Δ/yck2Δ strain had wild-type susceptibility to cyclosporine and FK506, suggesting that CaYck2p functions independently from the Ca+/calcineurin pathway. Thus, in C. albicans, Yck2p is a multifunctional kinase that governs morphogenesis, biofilm formation, cell wall integrity, and host cell interactions. PMID:29107946
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Jung, Sook-In; Rodriguez, Natalie; Irrizary, Jihyun; Liboro, Karl; Bogarin, Thania; Macias, Marlene; Eivers, Edward; Porter, Edith; Filler, Scott G; Park, Hyunsook
2017-01-01
The regulatory networks governing morphogenesis of a pleomorphic fungus, Candida albicans are extremely complex and remain to be completely elucidated. This study investigated the function of C. albicans yeast casein kinase 2 (CaYck2p). The yck2Δ/yck2Δ strain displayed constitutive pseudohyphae in both yeast and hyphal growth conditions, and formed enhanced biofilm under non-biofilm inducing condition. This finding was further supported by gene expression analysis of the yck2Δ/yck2Δ strain which showed significant upregulation of UME6, a key transcriptional regulator of hyphal transition and biofilm formation, and cell wall protein genes ALS3, HWP1, and SUN41, all of which are associated with morphogenesis and biofilm architecture. The yck2Δ/yck2Δ strain was hypersensitive to cell wall damaging agents and had increased compensatory chitin deposition in the cell wall accompanied by an upregulation of the expression of the chitin synthase genes, CHS2, CHS3, and CHS8. Absence of CaYck2p also affected fungal-host interaction; the yck2Δ/yck2Δ strain had significantly reduced ability to damage host cells. However, the yck2Δ/yck2Δ strain had wild-type susceptibility to cyclosporine and FK506, suggesting that CaYck2p functions independently from the Ca+/calcineurin pathway. Thus, in C. albicans, Yck2p is a multifunctional kinase that governs morphogenesis, biofilm formation, cell wall integrity, and host cell interactions.
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[Fungal infectivities of implanted catheters due to Candida sp. Biofilms formation and resistance].
Seddiki, S M L; Boucherit-Otmani, Z; Boucherit, K; Kunkel, D
2015-06-01
Candidemia are the most common fungal infections in hospitals. However, the catheters are subject to be altered by Candida biofilms which increase the risk of invasive nosocomial infections due to the high resistance to antifungal agents. Therefore, the minimum inhibitory concentrations of planktonic (MIC) and sessile cells (CIMS) were evaluated. To review the in vivo biofilms structures of Candida sp. formed on the inner and/or external surfaces of collected catheters, we used scanning electron microscopy (SEM). The level of biofilm resistance was assessed against two conventional antifungal agents: amphotericin B (AmB), which belongs to the class of polyenes, and fluconazole (FLZ) which is an azole. The SEM observation of biofilms of Candida sp. reveals complex structures. Compared to MICs, the calculation of CIMS showed an increase of 32 times with AmB and of 128 times with FLZ. Catheters offer an ideal surface to Candida sp. to form biofilms. This complex structure induces the increase of the resistance of sessile cells against two antifungal agents, AmB and FLZ. Copyright © 2015 Elsevier Masson SAS. All rights reserved.
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Modelling biofilm-induced formation damage and biocide treatment in subsurface geosystems
Ezeuko, C C; Sen, A; Gates, I D
2013-01-01
Biofilm growth in subsurface porous media, and its treatment with biocides (antimicrobial agents), involves a complex interaction of biogeochemical processes which provide non-trivial mathematical modelling challenges. Although there are literature reports of mathematical models to evaluate biofilm tolerance to biocides, none of these models have investigated biocide treatment of biofilms growing in interconnected porous media with flow. In this paper, we present a numerical investigation using a pore network model of biofilm growth, formation damage and biocide treatment. The model includes three phases (aqueous, adsorbed biofilm, and solid matrix), a single growth-limiting nutrient and a single biocide dissolved in the water. Biofilm is assumed to contain a single species of microbe, in which each cell can be a viable persister, a viable non-persister, or non-viable (dead). Persisters describe small subpopulation of cells which are tolerant to biocide treatment. Biofilm tolerance to biocide treatment is regulated by persister cells and includes ‘innate’ and ‘biocide-induced’ factors. Simulations demonstrate that biofilm tolerance to biocides can increase with biofilm maturity, and that biocide treatment alone does not reverse biofilm-induced formation damage. Also, a successful application of biological permeability conformance treatment involving geologic layers with flow communication is more complicated than simply engineering the attachment of biofilm-forming cells at desired sites. PMID:23164434
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Associations between fungal species and water-damaged building materials.
Andersen, Birgitte; Frisvad, Jens C; Søndergaard, Ib; Rasmussen, Ib S; Larsen, Lisbeth S
2011-06-01
Fungal growth in damp or water-damaged buildings worldwide is an increasing problem, which has adverse effects on both the occupants and the buildings. Air sampling alone in moldy buildings does not reveal the full diversity of fungal species growing on building materials. One aim of this study was to estimate the qualitative and quantitative diversity of fungi growing on damp or water-damaged building materials. Another was to determine if associations exist between the most commonly found fungal species and different types of materials. More than 5,300 surface samples were taken by means of V8 contact plates from materials with visible fungal growth. Fungal identifications and information on building material components were analyzed using multivariate statistic methods to determine associations between fungi and material components. The results confirmed that Penicillium chrysogenum and Aspergillus versicolor are the most common fungal species in water-damaged buildings. The results also showed Chaetomium spp., Acremonium spp., and Ulocladium spp. to be very common on damp building materials. Analyses show that associated mycobiotas exist on different building materials. Associations were found between (i) Acremonium spp., Penicillium chrysogenum, Stachybotrys spp., Ulocladium spp., and gypsum and wallpaper, (ii) Arthrinium phaeospermum, Aureobasidium pullulans, Cladosporium herbarum, Trichoderma spp., yeasts, and different types of wood and plywood, and (iii) Aspergillus fumigatus, Aspergillus melleus, Aspergillus niger, Aspergillus ochraceus, Chaetomium spp., Mucor racemosus, Mucor spinosus, and concrete and other floor-related materials. These results can be used to develop new and resistant building materials and relevant allergen extracts and to help focus research on relevant mycotoxins, microbial volatile organic compounds (MVOCs), and microparticles released into the indoor environment.
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Associations between Fungal Species and Water-Damaged Building Materials ▿
Andersen, Birgitte; Frisvad, Jens C.; Søndergaard, Ib; Rasmussen, Ib S.; Larsen, Lisbeth S.
2011-01-01
Fungal growth in damp or water-damaged buildings worldwide is an increasing problem, which has adverse effects on both the occupants and the buildings. Air sampling alone in moldy buildings does not reveal the full diversity of fungal species growing on building materials. One aim of this study was to estimate the qualitative and quantitative diversity of fungi growing on damp or water-damaged building materials. Another was to determine if associations exist between the most commonly found fungal species and different types of materials. More than 5,300 surface samples were taken by means of V8 contact plates from materials with visible fungal growth. Fungal identifications and information on building material components were analyzed using multivariate statistic methods to determine associations between fungi and material components. The results confirmed that Penicillium chrysogenum and Aspergillus versicolor are the most common fungal species in water-damaged buildings. The results also showed Chaetomium spp., Acremonium spp., and Ulocladium spp. to be very common on damp building materials. Analyses show that associated mycobiotas exist on different building materials. Associations were found between (i) Acremonium spp., Penicillium chrysogenum, Stachybotrys spp., Ulocladium spp., and gypsum and wallpaper, (ii) Arthrinium phaeospermum, Aureobasidium pullulans, Cladosporium herbarum, Trichoderma spp., yeasts, and different types of wood and plywood, and (iii) Aspergillus fumigatus, Aspergillus melleus, Aspergillus niger, Aspergillus ochraceus, Chaetomium spp., Mucor racemosus, Mucor spinosus, and concrete and other floor-related materials. These results can be used to develop new and resistant building materials and relevant allergen extracts and to help focus research on relevant mycotoxins, microbial volatile organic compounds (MVOCs), and microparticles released into the indoor environment. PMID:21531835
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Bertolini, M M; Xu, H; Sobue, T; Nobile, C J; Del Bel Cury, A A; Dongari-Bagtzoglou, A
2015-08-01
Candida albicans and streptococci of the mitis group form communities in multiple oral sites, where moisture and nutrient availability can change spatially or temporally. This study evaluated structural and virulence characteristics of Candida-streptococcal biofilms formed on moist or semidry mucosal surfaces, and tested the effects of nutrient availability and hyphal morphotype on dual-species biofilms. Three-dimensional models of the oral mucosa formed by immortalized keratinocytes on a fibroblast-embedded collagenous matrix were used. Infections were carried out using Streptococcus oralis strain 34, in combination with a C. albicans wild-type strain, or pseudohyphal-forming mutant strains. Increased moisture promoted a homogeneous surface biofilm by C. albicans. Dual biofilms had a stratified structure, with streptococci growing in close contact with the mucosa and fungi growing on the bacterial surface. Under semidry conditions, Candida formed localized foci of dense growth, which promoted focal growth of streptococci in mixed biofilms. Candida biofilm biovolume was greater under moist conditions, albeit with minimal tissue invasion, compared with semidry conditions. Supplementing the infection medium with nutrients under semidry conditions intensified growth, biofilm biovolume and tissue invasion/damage, without changing biofilm structure. Under these conditions, the pseudohyphal mutants and S. oralis formed defective superficial biofilms, with most bacteria in contact with the epithelial surface, below a pseudohyphal mass, resembling biofilms growing in a moist environment. The presence of S. oralis promoted fungal invasion and tissue damage under all conditions. We conclude that moisture, nutrient availability, hyphal morphotype and the presence of commensal bacteria influence the architecture and virulence characteristics of mucosal fungal biofilms. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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Rajendran, Ranjith; Borghi, Elisa; Falleni, Monica; Perdoni, Federica; Tosi, Delfina; Lappin, David F.; O'Donnell, Lindsay; Greetham, Darren; Ramage, Gordon
2015-01-01
Both neuronal acetylcholine and nonneuronal acetylcholine have been demonstrated to modulate inflammatory responses. Studies investigating the role of acetylcholine in the pathogenesis of bacterial infections have revealed contradictory findings with regard to disease outcome. At present, the role of acetylcholine in the pathogenesis of fungal infections is unknown. Therefore, the aim of this study was to determine whether acetylcholine plays a role in fungal biofilm formation and the pathogenesis of Candida albicans infection. The effect of acetylcholine on C. albicans biofilm formation and metabolism in vitro was assessed using a crystal violet assay and phenotypic microarray analysis. Its effect on the outcome of a C. albicans infection, fungal burden, and biofilm formation were investigated in vivo using a Galleria mellonella infection model. In addition, its effect on modulation of host immunity to C. albicans infection was also determined in vivo using hemocyte counts, cytospin analysis, larval histology, lysozyme assays, hemolytic assays, and real-time PCR. Acetylcholine was shown to have the ability to inhibit C. albicans biofilm formation in vitro and in vivo. In addition, acetylcholine protected G. mellonella larvae from C. albicans infection mortality. The in vivo protection occurred through acetylcholine enhancing the function of hemocytes while at the same time inhibiting C. albicans biofilm formation. Furthermore, acetylcholine also inhibited inflammation-induced damage to internal organs. This is the first demonstration of a role for acetylcholine in protection against fungal infections, in addition to being the first report that this molecule can inhibit C. albicans biofilm formation. Therefore, acetylcholine has the capacity to modulate complex host-fungal interactions and plays a role in dictating the pathogenesis of fungal infections. PMID:26092919
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Fungal Strategies to Evade the Host Immune Recognition.
Hernández-Chávez, Marco J; Pérez-García, Luis A; Niño-Vega, Gustavo A; Mora-Montes, Héctor M
2017-09-23
The recognition of fungal cells by the host immune system is key during the establishment of a protective anti-fungal response. Even though the immune system has evolved a vast number of processes to control these organisms, they have developed strategies to fight back, avoiding the proper recognition by immune components and thus interfering with the host protective mechanisms. Therefore, the strategies to evade the immune system are as important as the virulence factors and attributes that damage the host tissues and cells. Here, we performed a thorough revision of the main fungal tactics to escape from the host immunosurveillance processes. These include the composition and organization of the cell wall, the fungal capsule, the formation of titan cells, biofilms, and asteroid bodies; the ability to undergo dimorphism; and the escape from nutritional immunity, extracellular traps, phagocytosis, and the action of humoral immune effectors.
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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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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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Rajendran, Ranjith; Borghi, Elisa; Falleni, Monica; Perdoni, Federica; Tosi, Delfina; Lappin, David F; O'Donnell, Lindsay; Greetham, Darren; Ramage, Gordon; Nile, Christopher
2015-08-01
Both neuronal acetylcholine and nonneuronal acetylcholine have been demonstrated to modulate inflammatory responses. Studies investigating the role of acetylcholine in the pathogenesis of bacterial infections have revealed contradictory findings with regard to disease outcome. At present, the role of acetylcholine in the pathogenesis of fungal infections is unknown. Therefore, the aim of this study was to determine whether acetylcholine plays a role in fungal biofilm formation and the pathogenesis of Candida albicans infection. The effect of acetylcholine on C. albicans biofilm formation and metabolism in vitro was assessed using a crystal violet assay and phenotypic microarray analysis. Its effect on the outcome of a C. albicans infection, fungal burden, and biofilm formation were investigated in vivo using a Galleria mellonella infection model. In addition, its effect on modulation of host immunity to C. albicans infection was also determined in vivo using hemocyte counts, cytospin analysis, larval histology, lysozyme assays, hemolytic assays, and real-time PCR. Acetylcholine was shown to have the ability to inhibit C. albicans biofilm formation in vitro and in vivo. In addition, acetylcholine protected G. mellonella larvae from C. albicans infection mortality. The in vivo protection occurred through acetylcholine enhancing the function of hemocytes while at the same time inhibiting C. albicans biofilm formation. Furthermore, acetylcholine also inhibited inflammation-induced damage to internal organs. This is the first demonstration of a role for acetylcholine in protection against fungal infections, in addition to being the first report that this molecule can inhibit C. albicans biofilm formation. Therefore, acetylcholine has the capacity to modulate complex host-fungal interactions and plays a role in dictating the pathogenesis of fungal infections. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
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Zacchino, Susana A; Butassi, Estefanía; Cordisco, Estefanía; Svetaz, Laura A
2017-12-15
works respectively. Regarding combinations against bacterial biofilms, in vitro studies were performed in all works by using several different methods of higher variety than the used against fungal biofilms. Biofilms of both the gram (+) and gram (-) bacteria were prepared, although biofilm of Staphylococcus spp. were the most used in the collected works. Among the discovered potentiators of antibacterial drugs, 75% were terpenes, including mono, di- and triterpenes, and, among the atibacterial drugs, several structurally diverse types were used in the combinations: aminoglycosides, β-lactams, glucopeptides and fluoroquinolones. The potentiating capacity of natural products, mainly terpenes, on the antibiofilm effect of antimicrobial drugs opens a wide range of possibilities for the combination antimicrobial therapy. More in vivo studies on combinations of natural products with antimicrobial drugs acting against biofilms are highly required to cope the difficult to treat biofilm-associated infections. Copyright © 2017 Elsevier GmbH. All rights reserved.
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Fungal Biofilms: Targets for the Development of Novel Strategies in Plant Disease Management.
Villa, Federica; Cappitelli, Francesca; Cortesi, Paolo; Kunova, Andrea
2017-01-01
The global food supply has been facing increasing challenges during the first decades of the 21 st century. Disease in plants is an important constraint to worldwide crop production, accounting for 20-40% of its annual harvest loss. Although the use of resistant varieties, good water management and agronomic practices are valid management tools in counteracting plant diseases, there are still many pathosystems where fungicides are widely used for disease management. However, restrictive regulations and increasing concern regarding the risk to human health and the environment, along with the incidence of fungicide resistance, have discouraged their use and have prompted for a search for new efficient, ecologically friendly and sustainable disease management strategies. The recent evidence of biofilm formation by fungal phytopathogens provides the scientific framework for designing and adapting methods and concepts developed by biofilm research that could be integrated in IPM practices. In this perspective paper, we provide evidence to support the view that the biofilm lifestyle plays a critical role in the pathogenesis of plant diseases. We describe the main factors limiting the durability of single-site fungicides, and we assemble the current knowledge on pesticide resistance in the specific context of the biofilm lifestyle. Finally, we illustrate the potential of antibiofilm compounds at sub-lethal concentrations for the development of an innovative, eco-sustainable strategy to counteract phytopathogenic fungi. Such fungicide-free solutions will be instrumental in reducing disease severity, and will permit more prudent use of fungicides decreasing thus the selection of resistant forms and safeguarding the environment.
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Pasanen, A L; Rautiala, S; Kasanen, J P; Raunio, P; Rantamäki, J; Kalliokoski, P
2000-06-01
We determined the moisture levels, relative humidity (RH) or moisture content (MC) of materials, and concentrations of culturable fungi, actinomycetes and total spores as well as a composition of fungal flora in 122 building material samples collected from 18 moisture problem buildings. The purpose of this work was to clarify if the is any correlation between the moisture parameters and microbial levels or generic composition depending on the type of materials and the time passed after a water damage. The results showed an agreement between the concentrations of total spores and culturable fungi for the wood, wood-based and gypsum board samples (r > 0.47). The concentrations of total spores and/or culturable fungi correlated with RH of materials particularly among the wood and insulation materials (r > 0.79), but not usually with MC (r < 0.45). For the samples collected from ongoing damage, there was a correlation between RH of materials and the concentrations of total spores and culturable fungi (r > 0.51), while such a relationship could not be observed for the samples taken from dry damage. A wide range of fungal species were found in the samples from ongoing damage, whereas Penicillia and in some cases yeasts dominated the fungal flora in the dry samples. This study indicates that fungal contamination can be evaluated on the basis of moisture measurements of constructions in ongoing damage, but the measurements are not solely adequate for estimation of possible microbial growth in dry damage.
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Polyethylene Based Materials for Biofilm Carriers Used in Wastewater Treatment
NASA Astrophysics Data System (ADS)
Moga, I. C.; Iordache, O. I.; Petrescu, G.; Pricop, F.; Dumitrescu, I.
2018-06-01
The moving bed biofilm technology is based on biofilm carriers on which consortia of microorganisms attach, develop and grow. Around the world are known many biofilm carrier variants made of varied materials. The most common materials are based on polyethylene since this material has a close to water density. The authors propose a novel biofilm carrier to be used in tertiary treatment for tannery and paper-mill wastewaters. The biological treatment is based on fungal activity. The selected fungal strains will be grown on innovative polyethylene carriers containing cellulose. The carrier will be designed to be exploited in a moving bed bioreactor and to favour fungal growth in the presence of competing bacteria.
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Yuan, Shi-Min
2016-01-01
Fungal endocarditis is a rare and fatal condition. The Candida and Aspergillus species are the two most common etiologic fungi found responsible for fungal endocarditis. Fever and changing heart murmur are the most common clinical manifestations. Some patients may have a fever of unknown origin as the onset symptom. The diagnosis of fungal endocarditis is challenging, and diagnosis of prosthetic valve fungal endocarditis is extremely difficult. The optimum antifungal therapy still remains debatable. Treating Candida endocarditis can be difficult because the Candida species can form biofilms on native and prosthetic heart valves. Combined treatment appears superior to monotherapy. Combination of antifungal therapy and surgical debridement might bring about better prognosis.
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Novel entries in a fungal biofilm matrix encyclopedia
USDA-ARS?s Scientific Manuscript database
Virulence of Candida albicans is linked with its ability to form biofilms. Once established, biofilm infections are nearly impossible to eradicate. Biofilm cells live immersed in a self-produced matrix, a blend of extracellular biopolymers, many of which are uncharacterized. In this study, we conduc...
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Dyavaiah, Madhu; Ramani, Rama; Chu, David S; Ritterband, David C; Shah, Mahendra K; Samsonoff, William A; Chaturvedi, Sudha; Chaturvedi, Vishnu
2007-01-01
Background To characterize Fusarium isolates from recent cases of fungal keratitis in contact lens wearers, and to investigate fungal association with MoistureLoc solution. Methods We studied six fungal isolates from recent cases of keratitis in New York State. The isolates were characterized by nucleotide sequencing and phylogenetic analyses of multiple genes, and then typed using minisatellite and microsatellite probes. Experimental fungal biofilm formation was tested by standard methods. MoistureLoc solutions were tested in biofouling studies for their efficacy in elimination of Fusarium contamination. Results Fusarium solani – corneal ulcers (2 isolates), lens case (1 isolate), and F. oxysporum – corneal ulcer (1 isolate), eye (1 isolate), were recovered from five patients. An opened bottle of MoistureLoc solution provided by a patient also yielded F. solani. Two distinct genotypes of F. solani as well as of F. oxysporum were present in the isolated strains. Remarkably, F. solani strains from the lens case and lens solution in one instance were similar, based on phylogenetic analyses and molecular typing. The solution isolate of F. solani formed biofilm on contact lenses in control conditions, but not when co-incubated with MoistureLoc solution. Both freshly opened and 3-month old MoistureLoc solutions effectively killed F. solani and F. oxysporum, when fungal contamination was simulated under recommended lens treatment regimen (4-hr). However, simulation of inappropriate use (15 – 60 min) led to the recovery of less than 1% of original inoculum of F. solani or F. oxysporum. Conclusion Temporary survival of F. solani and F. oxysporum in MoistureLoc suggested that improper lens cleaning regimen could be a possible contributing factor in recent infections. PMID:17263885
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Yuan, Shi-Min
2016-01-01
Fungal endocarditis is a rare and fatal condition. The Candida and Aspergillus species are the two most common etiologic fungi found responsible for fungal endocarditis. Fever and changing heart murmur are the most common clinical manifestations. Some patients may have a fever of unknown origin as the onset symptom. The diagnosis of fungal endocarditis is challenging, and diagnosis of prosthetic valve fungal endocarditis is extremely difficult. The optimum antifungal therapy still remains debatable. Treating Candida endocarditis can be difficult because the Candida species can form biofilms on native and prosthetic heart valves. Combined treatment appears superior to monotherapy. Combination of antifungal therapy and surgical debridement might bring about better prognosis. PMID:27737409
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Interactions between abundant fungal species influence the fungal community assemblage on limestone
Morón-Ríos, Alejandro; Ortega-Morales, Benjamin Otto; De la Rosa-García, Susana; Partida-Martínez, Laila Pamela; Quintana, Patricia; Alayón-Gamboa, José Armando; Cappello-García, Silvia; González-Gómez, Santiago
2017-01-01
The assembly of fungal communities on stone materials is mainly influenced by the differential bioreceptivity of such materials and environmental conditions. However, little is known about the role of fungal interactions in the colonization and establishment of fungal species. We analyzed the effects of intra- and interspecific interactions between 11 species of fungi in oligotrophic and copiotrophic media and on limestone coupons. In a previous study, these species were the most frequently isolated in the epilithic biofilms of limestone walls exposed to a subtropical climate. In the culture media, we found a greater frequency of intra- and interspecific inhibitory effects in the oligotrophic medium than in the copiotrophic medium. On the limestone coupons, all fungi were able to establish; however, the colonization success rate varied significantly. Cladosporium cladosporioides had a less extensive colonization in isolation (control) than in dual interactions (coexistence) with other species. Phoma eupyrena exhibited the highest colonization success rate and competitive dominance among all tested species. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses revealed that Pestalotiopsis maculans and Paraconiothyrium sp. produced calcium oxalate crystals during their growth on coupon surfaces, both in isolation and in dual interactions. Our results demonstrate that interactions between abundant fungal species influence the fungal colonization on substrates, the biomineralization and the fungal community assemblage growing in limestone biofilms. PMID:29211748
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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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Vandenbosch, Davy; De Canck, Evelien; Dhondt, Inne; Rigole, Petra; Nelis, Hans J; Coenye, Tom
2013-12-01
Infections related to fungal biofilms are difficult to treat due to the reduced susceptibility of sessile cells to most antifungal agents. Previous research has shown that 1-10% of sessile Candida cells survive treatment with high doses of miconazole (a fungicidal imidazole). The aim of this study was to identify genes involved in fungal biofilm formation and to unravel the mechanisms of resistance of these biofilms to miconazole. To this end, a screening of a Saccharomyces cerevisiae deletion mutant bank was carried out. Our results revealed that genes involved in peroxisomal transport and the biogenesis of the respiratory chain complex IV play an essential role in biofilm formation. On the other hand, genes involved in transcription and peroxisomal and mitochondrial organization seem to highly influence the susceptibility to miconazole of yeast biofilms. Additionally, our data confirm previous findings on genes involved in biofilm formation and in general stress responses. Our data suggest the involvement of peroxisomes in biofilm formation and miconazole resistance in fungal biofilms. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.
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Filamentous fungal biofilm for production of human drug metabolites.
Amadio, Jessica; Casey, Eoin; Murphy, Cormac D
2013-07-01
In drug development, access to drug metabolites is essential for assessment of toxicity and pharmacokinetic studies. Metabolites are usually acquired via chemical synthesis, although biological production is potentially more efficient with fewer waste management issues. A significant problem with the biological approach is the effective half-life of the biocatalyst, which can be resolved by immobilisation. The fungus Cunninghamella elegans is well established as a model of mammalian metabolism, although it has not yet been used to produce metabolites on a large scale. Here, we describe immobilisation of C. elegans as a biofilm, which can transform drugs to important human metabolites. The biofilm was cultivated on hydrophilic microtiter plates and in shake flasks containing a steel spring in contact with the glass. Fluorescence and confocal scanning laser microscopy revealed that the biofilm was composed of a dense network of hyphae, and biochemical analysis demonstrated that the matrix was predominantly polysaccharide. The medium composition was crucial for both biofilm formation and biotransformation of flurbiprofen. In shake flasks, the biofilm transformed 86% of the flurbiprofen added to hydroxylated metabolites within 24 h, which was slightly more than planktonic cultures (76%). The biofilm had a longer effective lifetime than the planktonic cells, which underwent lysis after 2×72 h cycles, and diluting the Sabouraud dextrose broth enabled the thickness of the biofilm to be controlled while retaining transformation efficiency. Thus, C. elegans biofilm has the potential to be applied as a robust biocatalyst for the production of human drug metabolites required for drug development.
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Assessment of fungal diversity in a water-damaged office building.
Green, Brett J; Lemons, Angela R; Park, Yeonmi; Cox-Ganser, Jean M; Park, Ju-Hyeong
2017-04-01
Recent studies have described fungal communities in indoor environments using gene sequencing-based approaches. In this study, dust-borne fungal communities were elucidated from a water-damaged office building located in the northeastern region of the United States using internal transcribed spacer (ITS) rRNA gene sequencing. Genomic DNA was extracted from 5 mg of floor dust derived from 22 samples collected from either the lower floors (n = 8) or a top floor (n = 14) of the office building. ITS gene sequencing resolved a total of 933 ITS sequences and was clustered into 216 fungal operational taxonomic units (OTUs). Analysis of fungal OTUs at the 97% similarity threshold showed a difference between the lower and top floors that was marginally significant (p = 0.049). Species richness and diversity indices were reduced in the lower floor samples compared to the top floor samples and there was a high degree of compositional dissimilarity within and between the two different areas within the building. Fungal OTUs were placed in the phyla Ascomycota (55%), Basidiomycota (41%), Zygomycota (3%), Glomeromycota (0.4%), Chytridiomycota (0.3%), and unassigned fungi (0.5%). The Ascomycota classes with the highest relative abundances included the Dothideomycetes (30%) and Eurotiomycetes (16%). The Basidiomycota consisted of the classes Ustilaginomycetes (14%), Tremellomycetes (11%), and Agaricomycetes (8%). Sequence reads derived from the plant pathogen Ustilago syntherismae were the most abundant in the analysis as were obligate Basidiomycota yeast species that accounted for 12% and 11% of fungal ITS sequences, respectively. ITS gene sequencing provides additional insight into the diversity of fungal OTUs. These data further highlight the contribution of fungi placed in the phylum Basidiomycota, obligate yeasts, as well as xerophilic species that are typically not resolved using traditional culture methods.
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Shukla, Nandini; Osmani, Aysha H.; Osmani, Stephen A.
2017-01-01
How microtubules (MTs) are regulated during fungal biofilm formation is unknown. By tracking MT +end–binding proteins (+TIPS) in Aspergillus nidulans, we find that MTs are regulated to depolymerize within forming fungal biofilms. During this process, EB1, dynein, and ClipA form transient fibrous and then bar-like structures, novel configurations for +TIPS. Cells also respond in an autonomous manner, with cells separated by a septum able to maintain different MT dynamics. Surprisingly, all cells with depolymerized MTs rapidly repolymerize their MTs after air exchange above the static culture medium of biofilms. Although the specific gasotransmitter for this biofilm response is not known, we find that addition of hydrogen sulfide gas to growing cells recapitulates all aspects of reversible MT depolymerization and transient formation of +TIPs bars. However, as biofilms mature, physical removal of part of the biofilm is required to promote MT repolymerization, which occurs at the new biofilm edge. We further show MT depolymerization within biofilms is regulated by the SrbA hypoxic transcription factor and that without SrbA, MTs are maintained as biofilms form. This reveals a new mode of MT regulation in response to changing gaseous biofilm microenvironments, which could contribute to the unique characteristics of fungal biofilms in medical and industrial settings. PMID:28057761
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Raman, Namrata; Lee, Myung-Ryul
2014-01-01
Candida albicans is the most common fungal pathogen responsible for hospital-acquired infections. Most C albicans infections are associated with the implantation of medical devices that act as points of entry for the pathogen and as substrates for the growth of fungal biofilms that are notoriously difficult to eliminate by systemic administration of conventional antifungal agents. In this study, we report a fill-and-purge approach to the layer-by-layer fabrication of biocompatible, nanoscale ‘polyelectrolyte multilayers’ (PEMs) on the luminal surfaces of flexible catheters, and an investigation of this platform for the localized, intraluminal release of a cationic β-peptide-based antifungal agent. We demonstrate that polyethylene catheter tubes with luminal surfaces coated with multilayers ~700 nm thick fabricated from poly-L-glutamic acid (PGA) and poly-L-lysine (PLL) can be loaded, post-fabrication, by infusion with β-peptide, and that this approach promotes extended intraluminal release of this agent (over ~4 months) when incubated in physiological media. The β-peptide remained potent against intraluminal inoculation of the catheters with C albicans and substantially reduced the formation of C albicans biofilms on the inner surfaces of film-coated catheters. Finally, we report that these β-peptide-loaded coatings exhibit antifungal activity under conditions that simulate intermittent catheter use and microbial challenge for at least three weeks. We conclude that β-peptide-loaded PEMs offer a novel and promising approach to kill C albicans and prevent fungal biofilm formation on surfaces, with the potential to substantially reduce the incidence of device-associated infections in indwelling catheters. β-Peptides comprise a promising new class of antifungal agents that could help address problems associated with the use of conventional antifungal agents. The versatility of the layer-by-layer approach used here thus suggests additional opportunities to
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Raman, Namrata; Lee, Myung-Ryul; Palecek, Sean P; Lynn, David M
2014-10-10
Candida albicans is the most common fungal pathogen responsible for hospital-acquired infections. Most C. albicans infections are associated with the implantation of medical devices that act as points of entry for the pathogen and as substrates for the growth of fungal biofilms that are notoriously difficult to eliminate by systemic administration of conventional antifungal agents. In this study, we report a fill-and-purge approach to the layer-by-layer fabrication of biocompatible, nanoscale 'polyelectrolyte multilayers' (PEMs) on the luminal surfaces of flexible catheters, and an investigation of this platform for the localized, intraluminal release of a cationic β-peptide-based antifungal agent. We demonstrate that polyethylene catheter tubes with luminal surfaces coated with multilayers ~700nm thick fabricated from poly-l-glutamic acid (PGA) and poly-l-lysine (PLL) can be loaded, post-fabrication, by infusion with β-peptide, and that this approach promotes extended intraluminal release of this agent (over ~4months) when incubated in physiological media. The β-peptide remained potent against intraluminal inoculation of the catheters with C. albicans and substantially reduced the formation of C. albicans biofilms on the inner surfaces of film-coated catheters. Finally, we report that these β-peptide-loaded coatings exhibit antifungal activity under conditions that simulate intermittent catheter use and microbial challenge for at least three weeks. We conclude that β-peptide-loaded PEMs offer a novel and promising approach to kill C. albicans and prevent fungal biofilm formation on surfaces, with the potential to substantially reduce the incidence of device-associated infections in indwelling catheters. β-Peptides comprise a promising new class of antifungal agents that could help address problems associated with the use of conventional antifungal agents. The versatility of the layer-by-layer approach used here thus suggests additional opportunities to
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Novel entries in a fungal biofilm matrix encyclopedia.
Zarnowski, Robert; Westler, William M; Lacmbouh, Ghislain Ade; Marita, Jane M; Bothe, Jameson R; Bernhardt, Jörg; Lounes-Hadj Sahraoui, Anissa; Fontaine, Joël; Sanchez, Hiram; Hatfield, Ronald D; Ntambi, James M; Nett, Jeniel E; Mitchell, Aaron P; Andes, David R
2014-08-05
Virulence of Candida is linked with its ability to form biofilms. Once established, biofilm infections are nearly impossible to eradicate. Biofilm cells live immersed in a self-produced matrix, a blend of extracellular biopolymers, many of which are uncharacterized. In this study, we provide a comprehensive analysis of the matrix manufactured by Candida albicans both in vitro and in a clinical niche animal model. We further explore the function of matrix components, including the impact on drug resistance. We uncovered components from each of the macromolecular classes (55% protein, 25% carbohydrate, 15% lipid, and 5% nucleic acid) in the C. albicans biofilm matrix. Three individual polysaccharides were identified and were suggested to interact physically. Surprisingly, a previously identified polysaccharide of functional importance, β-1,3-glucan, comprised only a small portion of the total matrix carbohydrate. Newly described, more abundant polysaccharides included α-1,2 branched α-1,6-mannans (87%) associated with unbranched β-1,6-glucans (13%) in an apparent mannan-glucan complex (MGCx). Functional matrix proteomic analysis revealed 458 distinct activities. The matrix lipids consisted of neutral glycerolipids (89.1%), polar glycerolipids (10.4%), and sphingolipids (0.5%). Examination of matrix nucleic acid identified DNA, primarily noncoding sequences. Several of the in vitro matrix components, including proteins and each of the polysaccharides, were also present in the matrix of a clinically relevant in vivo biofilm. Nuclear magnetic resonance (NMR) analysis demonstrated interaction of aggregate matrix with the antifungal fluconazole, consistent with a role in drug impedance and contribution of multiple matrix components. Importance: This report is the first to decipher the complex and unique macromolecular composition of the Candida biofilm matrix, demonstrate the clinical relevance of matrix components, and show that multiple matrix components are needed
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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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Efficacy of surface-generated nitric oxide against Candida albicans adhesion and biofilm formation.
Privett, Benjamin J; Nutz, Steven T; Schoenfisch, Mark H
2010-11-01
This report details the efficacy of nitric oxide (NO)-releasing xerogel surfaces composed of N-(6-aminohexyl)aminopropyl trimethoxysilane (AHAP3) and isobutyltrimethoxysilane (BTMOS) against Candida albicans adhesion, viability, and biofilm formation. A parallel plate flow cell assay was used to examine the effect of NO on planktonic fungal cells. Nitric oxide fluxes as low as 14 pmol cm(-2) s(-1) were sufficient to reduce fungal adhesion by ∼49% over the controls after 90 min. By utilizing a fluorescence live/dead assay and replicate plating, NO flux was determined to reduce fungal viability in a dose-dependent manner. The formation of C. albicans biofilms on NO-releasing xerogel-coated silicon rubber (SiR) coupons was impeded when compared to control (non-NO-releasing) and bare SiR surfaces. The synergistic efficacy of NO and silver sulfadiazine against adhered fungal cells and biofilms is reported with increased killing and biofilm inhibition over NO alone.
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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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Bacterial GtfB Augments Candida albicans Accumulation in Cross-Kingdom Biofilms.
Ellepola, K; Liu, Y; Cao, T; Koo, H; Seneviratne, C J
2017-09-01
Streptococcus mutans is a biofilm-forming oral pathogen commonly associated with dental caries. Clinical studies have shown that S. mutans is often detected with Candida albicans in early childhood caries. Although the C. albicans presence has been shown to enhance bacterial accumulation in biofilms, the influence of S. mutans on fungal biology in this mixed-species relationship remains largely uncharacterized. Therefore, we aimed to investigate how the presence of S. mutans influences C. albicans biofilm development and coexistence. Using a newly established haploid biofilm model of C. albicans, we found that S. mutans augmented haploid C. albicans accumulation in mixed-species biofilms. Similarly, diploid C. albicans also showed enhanced biofilm formation in the presence of S. mutans. Surprisingly, the presence of S. mutans restored the biofilm-forming ability of C. albicans bcr1Δ mutant and bcr1Δ/Δ mutant, which is known to be severely defective in biofilm formation when grown as single species. Moreover, C. albicans hyphal growth factor HWP1 as well as ALS1 and ALS3, which are also involved in fungal biofilm formation, were upregulated in the presence of S. mutans. Subsequently, we found that S. mutans-derived glucosyltransferase B (GtfB) itself can promote C. albicans biofilm development. Interestingly, GtfB was able to increase the expression of HWP1, ALS1, and ALS3 genes in the C. albicans diploid wild-type SC5314 and bcr1Δ/Δ, leading to enhanced fungal biofilms. Hence, the present study demonstrates that a bacterial exoenzyme (GtfB) augments the C. albicans counterpart in mixed-species biofilms through a BCR1-independent mechanism. This novel finding may explain the mutualistic role of S. mutans and C. albicans in cariogenic biofilms.
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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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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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Liu, Jiang; Deng, Jun-cai; Yang, Cai-qiong; Huang, Ni; Chang, Xiao-li; Zhang, Jing; Yang, Feng; Liu, Wei-guo; Wang, Xiao-chun; Yong, Tai-wen; Du, Jun-bo; Shu, Kai; Yang, Wen-yu
2017-01-01
Continuous rain and an abnormally wet climate during harvest can easily lead to soybean plants being damaged by field mold (FM), which can reduce seed yield and quality. However, to date, the underlying pathogen and its resistance mechanism have remained unclear. The objective of the present study was to investigate the fungal diversity of various soybean varieties and to identify and confirm the FM pathogenic fungi. A total of 62,382 fungal ITS1 sequences clustered into 164 operational taxonomic units (OTUs) with 97% sequence similarity; 69 taxa were recovered from the samples by internal transcribed spacer (ITS) region sequencing. The fungal community compositions differed among the tested soybeans, with 42 OTUs being amplified from all varieties. The quadratic relationships between fungal diversity and organ-specific mildew indexes were analyzed, confirming that mildew on soybean pods can mitigate FM damage to the seeds. In addition, four potentially pathogenic fungi were isolated from FM-damaged soybean fruits; morphological and molecular identification confirmed these fungi as Aspergillus flavus, A. niger, Fusarium moniliforme, and Penicillium chrysogenum. Further re-inoculation experiments demonstrated that F. moniliforme is dominant among these FM pathogenic fungi. These results lay the foundation for future studies on mitigating or preventing FM damage to soybean. PMID:28515718
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Novel Entries in a Fungal Biofilm Matrix Encyclopedia
Zarnowski, Robert; Westler, William M.; Lacmbouh, Ghislain Ade; Marita, Jane M.; Bothe, Jameson R.; Bernhardt, Jörg; Lounes-Hadj Sahraoui, Anissa; Fontaine, Joël; Sanchez, Hiram; Hatfield, Ronald D.; Ntambi, James M.; Nett, Jeniel E.; Mitchell, Aaron P.
2014-01-01
ABSTRACT Virulence of Candida is linked with its ability to form biofilms. Once established, biofilm infections are nearly impossible to eradicate. Biofilm cells live immersed in a self-produced matrix, a blend of extracellular biopolymers, many of which are uncharacterized. In this study, we provide a comprehensive analysis of the matrix manufactured by Candida albicans both in vitro and in a clinical niche animal model. We further explore the function of matrix components, including the impact on drug resistance. We uncovered components from each of the macromolecular classes (55% protein, 25% carbohydrate, 15% lipid, and 5% nucleic acid) in the C. albicans biofilm matrix. Three individual polysaccharides were identified and were suggested to interact physically. Surprisingly, a previously identified polysaccharide of functional importance, β-1,3-glucan, comprised only a small portion of the total matrix carbohydrate. Newly described, more abundant polysaccharides included α-1,2 branched α-1,6-mannans (87%) associated with unbranched β-1,6-glucans (13%) in an apparent mannan-glucan complex (MGCx). Functional matrix proteomic analysis revealed 458 distinct activities. The matrix lipids consisted of neutral glycerolipids (89.1%), polar glycerolipids (10.4%), and sphingolipids (0.5%). Examination of matrix nucleic acid identified DNA, primarily noncoding sequences. Several of the in vitro matrix components, including proteins and each of the polysaccharides, were also present in the matrix of a clinically relevant in vivo biofilm. Nuclear magnetic resonance (NMR) analysis demonstrated interaction of aggregate matrix with the antifungal fluconazole, consistent with a role in drug impedance and contribution of multiple matrix components. PMID:25096878
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Tóth, László; Csomor, Péter; Sziklai, István; Karosi, Tamás
2011-10-01
The pathomechanism of chronic rhinosinusitis with nasal polyposis (CRS/NP) seems to be unclear. Bacterial-, fungal- and combined biofilms might play a potential role in the pathogenesis of various inflammatory diseases and recently in CRS/NP. A prospective, blinded observational study was performed to confirm that the combination of conventional hematoxylin-eosin (HE) and Gram staining protocols could be used to detect bacterial and fungal biofilms in patients with CRS/NP. A total of 50 patients with CRS/NP undergoing endoscopic sinus surgery (ESS) were analyzed. The negative control group consisted of 12 patients undergoing septoplasty for nasal obstruction without CRS/NP. The nasal polyps and inferior turbinate mucosa specimens applied as negative controls were processed to HE and Gram staining. Biofilm was detected in 44 of 50 patients with CRS/NP and in none of 12 negative controls. In our series, HE method showed an obvious correlation with the results of Gram staining and was allocated to be a good predictor of biofilm existence. It was found that the microscopic structure and thickness of biofilms were strongly associated with the integrity of nasal mucosa and with the characteristics of subepithelial cellular infiltration. This study confirmed the presence of bacterial and fungal biofilms on the surface of NPs obtained from patients with CRS. Since biofilms may affect the severity and recurrence rate of CRS treated by ESS they should be detected histologically. In conclusion, HE staining combined with Gram protocol is a robust and reliable method for the detection of bacterial and fungal biofilms in CRS/NP.
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Microbial Diversity and Putative Opportunistic Pathogens in Dishwasher Biofilm Communities
2018-01-01
ABSTRACT Extreme habitats are not only limited to natural environments, but also exist in manmade systems, for instance, household appliances such as dishwashers. Limiting factors, such as high temperatures, high and low pHs, high NaCl concentrations, presence of detergents, and shear force from water during washing cycles, define microbial survival in this extreme system. Fungal and bacterial diversity in biofilms isolated from rubber seals of 24 different household dishwashers was investigated using next-generation sequencing. Bacterial genera such as Pseudomonas, Escherichia, and Acinetobacter, known to include opportunistic pathogens, were represented in most samples. The most frequently encountered fungal genera in these samples belonged to Candida, Cryptococcus, and Rhodotorula, also known to include opportunistic pathogenic representatives. This study showed how specific conditions of the dishwashers impact the abundance of microbial groups and investigated the interkingdom and intrakingdom interactions that shape these biofilms. The age, usage frequency, and hardness of incoming tap water of dishwashers had significant impact on bacterial and fungal community compositions. Representatives of Candida spp. were found at the highest prevalence (100%) in all dishwashers and are assumed to be one of the first colonizers in recently purchased dishwashers. Pairwise correlations in tested microbiomes showed that certain bacterial groups cooccur, as did the fungal groups. In mixed bacterial-fungal biofilms, early adhesion, contact, and interactions were vital in the process of biofilm formation, where mixed complexes of bacteria and fungi could provide a preliminary biogenic structure for the establishment of these biofilms. IMPORTANCE Worldwide demand for household appliances, such as dishwashers and washing machines, is increasing, as is the number of immunocompromised individuals. The harsh conditions in household dishwashers should prevent the growth of most
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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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Shukla, Nandini; Osmani, Aysha H; Osmani, Stephen A
2017-03-01
How microtubules (MTs) are regulated during fungal biofilm formation is unknown. By tracking MT +end-binding proteins (+TIPS) in Aspergillus nidulans , we find that MTs are regulated to depolymerize within forming fungal biofilms. During this process, EB1, dynein, and ClipA form transient fibrous and then bar-like structures, novel configurations for +TIPS. Cells also respond in an autonomous manner, with cells separated by a septum able to maintain different MT dynamics. Surprisingly, all cells with depolymerized MTs rapidly repolymerize their MTs after air exchange above the static culture medium of biofilms. Although the specific gasotransmitter for this biofilm response is not known, we find that addition of hydrogen sulfide gas to growing cells recapitulates all aspects of reversible MT depolymerization and transient formation of +TIPs bars. However, as biofilms mature, physical removal of part of the biofilm is required to promote MT repolymerization, which occurs at the new biofilm edge. We further show MT depolymerization within biofilms is regulated by the SrbA hypoxic transcription factor and that without SrbA, MTs are maintained as biofilms form. This reveals a new mode of MT regulation in response to changing gaseous biofilm microenvironments, which could contribute to the unique characteristics of fungal biofilms in medical and industrial settings. © 2017 Shukla et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).
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The Candida albicans Biofilm Matrix: Composition, Structure and Function.
Pierce, Christopher G; Vila, Taissa; Romo, Jesus A; Montelongo-Jauregui, Daniel; Wall, Gina; Ramasubramanian, Anand; Lopez-Ribot, Jose L
2017-03-01
A majority of infections caused by Candida albicans -the most frequent fungal pathogen-are associated with biofilm formation. A salient feature of C. albicans biofilms is the presence of the biofilm matrix. This matrix is composed of exopolymeric materials secreted by sessile cells within the biofilm, in which all classes of macromolecules are represented, and provides protection against environmental challenges. In this review, we summarize the knowledge accumulated during the last two decades on the composition, structure, and function of the C. albicans biofilm matrix. Knowledge of the matrix components, its structure, and function will help pave the way to novel strategies to combat C. albicans biofilm infections.
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The Candida albicans Biofilm Matrix: Composition, Structure and Function
Pierce, Christopher G.; Vila, Taissa; Romo, Jesus A.; Montelongo-Jauregui, Daniel; Wall, Gina; Ramasubramanian, Anand; Lopez-Ribot, Jose L.
2017-01-01
A majority of infections caused by Candida albicans—the most frequent fungal pathogen—are associated with biofilm formation. A salient feature of C. albicans biofilms is the presence of the biofilm matrix. This matrix is composed of exopolymeric materials secreted by sessile cells within the biofilm, in which all classes of macromolecules are represented, and provides protection against environmental challenges. In this review, we summarize the knowledge accumulated during the last two decades on the composition, structure, and function of the C. albicans biofilm matrix. Knowledge of the matrix components, its structure, and function will help pave the way to novel strategies to combat C. albicans biofilm infections. PMID:28516088
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Jackson, Desmond N.; Yang, Lin; Wu, ShiBiao; Kennelly, Edward J.
2015-01-01
Xanthochymol and garcinol, isoprenylated benzophenones purified from Garcinia xanthochymus fruits, showed multiple activities against Candida albicans biofilms. Both compounds effectively prevented emergence of fungal germ tubes and were also cytostatic, with MICs of 1 to 3 μM. The compounds therefore inhibited development of hyphae and subsequent biofilm maturation. Xanthochymol treatment of developing and mature biofilms induced cell death. In early biofilm development, killing had the characteristics of apoptosis, including externalization of phosphatidyl serine and DNA fragmentation, as evidenced by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) fluorescence. These activities resulted in failure of biofilm maturation and hyphal death in mature biofilms. In mature biofilms, xanthochymol and garcinol caused the death of biofilm hyphae, with 50% effective concentrations (EC50s) of 30 to 50 μM. Additionally, xanthochymol-mediated killing was complementary with fluconazole against mature biofilms, reducing the fluconazole EC50 from >1,024 μg/ml to 13 μg/ml. Therefore, xanthochymol has potential as an adjuvant for antifungal treatments as well as in studies of fungal apoptosis. PMID:26195512
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Control of Candida albicans Metabolism and Biofilm Formation by Pseudomonas aeruginosa Phenazines
Morales, Diana K.; Grahl, Nora; Okegbe, Chinweike; Dietrich, Lars E. P.; Jacobs, Nicholas J.; Hogan, Deborah A.
2013-01-01
ABSTRACT Candida albicans has developmental programs that govern transitions between yeast and filamentous morphologies and between unattached and biofilm lifestyles. Here, we report that filamentation, intercellular adherence, and biofilm development were inhibited during interactions between Candida albicans and Pseudomonas aeruginosa through the action of P. aeruginosa-produced phenazines. While phenazines are toxic to C. albicans at millimolar concentrations, we found that lower concentrations of any of three different phenazines (pyocyanin, phenazine methosulfate, and phenazine-1-carboxylate) allowed growth but affected the development of C. albicans wrinkled colony biofilms and inhibited the fungal yeast-to-filament transition. Phenazines impaired C. albicans growth on nonfermentable carbon sources and led to increased production of fermentation products (ethanol, glycerol, and acetate) in glucose-containing medium, leading us to propose that phenazines specifically inhibited respiration. Methylene blue, another inhibitor of respiration, also prevented the formation of structured colony biofilms. The inhibition of filamentation and colony wrinkling was not solely due to lowered extracellular pH induced by fermentation. Compared to smooth, unstructured colonies, wrinkled colony biofilms had higher oxygen concentrations within the colony, and wrinkled regions of these colonies had higher levels of respiration. Together, our data suggest that the structure of the fungal biofilm promotes access to oxygen and enhances respiratory metabolism and that the perturbation of respiration by bacterial molecules such as phenazines or compounds with similar activities disrupts these pathways. These findings may suggest new ways to limit fungal biofilms in the context of disease. PMID:23362320
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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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Lopez-Ribot, Jose L
2014-09-09
Among pathogenic fungi, Candida albicans is most frequently associated with biofilm formation, a lifestyle that is entirely different from the planktonic state. One of the distinguishing features of these biofilms is the presence of extracellular material, commonly referred to as the "biofilm matrix." The fungal biofilm matrix embeds sessile cells within these communities and plays important structural and physiological functions, including antifungal drug resistance with important clinical repercussions. This matrix is mostly self-produced by the fungal cells themselves and is composed of different types of biopolymers. In C. albicans, the main components of the biofilm matrix are carbohydrates, proteins, lipids, and DNA, but many of them remain unidentified and/or poorly characterized. In their recent article, Zarnowski et al. [mBio 5(4):e01333-14, 2014, doi:10.1128/mBio.01333-14] used a variety of biochemical and state-of-the-art "omic" approaches (glycomics, proteomics, and lipidomics) to identify and characterize unique biopolymers present in the C. albicans biofilm matrix. Besides generating a true "encyclopedic" catalog of individual moieties from each of the different macromolecular categories, results also provide important insights into structural and functional aspects of the fungal biofilm matrix, particularly the interaction between different components and the contribution of multiple matrix constituents to biofilm antifungal drug resistance. Copyright © 2014 Lopez-Ribot.
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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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2011-01-01
Background Indoor microbial contamination due to excess moisture is an important contributor to human illness in both residential and occupational settings. However, the census of microorganisms in the indoor environment is limited by the use of selective, culture-based detection techniques. By using clone library sequencing of full-length internal transcribed spacer region combined with quantitative polymerase chain reaction (qPCR) for 69 fungal species or assay groups and cultivation, we have been able to generate a more comprehensive description of the total indoor mycoflora. Using this suite of methods, we assessed the impact of moisture damage on the fungal community composition of settled dust and building material samples (n = 8 and 16, correspondingly). Water-damaged buildings (n = 2) were examined pre- and post- remediation, and compared with undamaged reference buildings (n = 2). Results Culture-dependent and independent methods were consistent in the dominant fungal taxa in dust, but sequencing revealed a five to ten times higher diversity at the genus level than culture or qPCR. Previously unknown, verified fungal phylotypes were detected in dust, accounting for 12% of all diversity. Fungal diversity, especially within classes Dothideomycetes and Agaricomycetes tended to be higher in the water damaged buildings. Fungal phylotypes detected in building materials were present in dust samples, but their proportion of total fungi was similar for damaged and reference buildings. The quantitative correlation between clone library phylotype frequencies and qPCR counts was moderate (r = 0.59, p < 0.01). Conclusions We examined a small number of target buildings and found indications of elevated fungal diversity associated with water damage. Some of the fungi in dust were attributable to building growth, but more information on the material-associated communities is needed in order to understand the dynamics of microbial communities between building structures
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Pitkäranta, Miia; Meklin, Teija; Hyvärinen, Anne; Nevalainen, Aino; Paulin, Lars; Auvinen, Petri; Lignell, Ulla; Rintala, Helena
2011-10-21
Indoor microbial contamination due to excess moisture is an important contributor to human illness in both residential and occupational settings. However, the census of microorganisms in the indoor environment is limited by the use of selective, culture-based detection techniques. By using clone library sequencing of full-length internal transcribed spacer region combined with quantitative polymerase chain reaction (qPCR) for 69 fungal species or assay groups and cultivation, we have been able to generate a more comprehensive description of the total indoor mycoflora. Using this suite of methods, we assessed the impact of moisture damage on the fungal community composition of settled dust and building material samples (n = 8 and 16, correspondingly). Water-damaged buildings (n = 2) were examined pre- and post- remediation, and compared with undamaged reference buildings (n = 2). Culture-dependent and independent methods were consistent in the dominant fungal taxa in dust, but sequencing revealed a five to ten times higher diversity at the genus level than culture or qPCR. Previously unknown, verified fungal phylotypes were detected in dust, accounting for 12% of all diversity. Fungal diversity, especially within classes Dothideomycetes and Agaricomycetes tended to be higher in the water damaged buildings. Fungal phylotypes detected in building materials were present in dust samples, but their proportion of total fungi was similar for damaged and reference buildings. The quantitative correlation between clone library phylotype frequencies and qPCR counts was moderate (r = 0.59, p < 0.01). We examined a small number of target buildings and found indications of elevated fungal diversity associated with water damage. Some of the fungi in dust were attributable to building growth, but more information on the material-associated communities is needed in order to understand the dynamics of microbial communities between building structures and dust. The sequencing
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Air- and Dustborne Mycoflora in Houses Free of Water Damage and Fungal Growth
Horner, W. Elliott; Worthan, Anthony G.; Morey, Philip R.
2004-01-01
Typically, studies on indoor fungal growth in buildings focus on structures with known or suspected water damage, moisture, and/or indoor fungal growth problems. Reference information on types of culturable fungi and total fungal levels are generally not available for buildings without these problems. This study assessed 50 detached single-family homes in metropolitan Atlanta, Ga., to establish a baseline of “normal and typical” types and concentrations of airborne and dustborne fungi in urban homes which were predetermined not to have noteworthy moisture problems or indoor fungal growth. Each home was visually examined, and samples of indoor and outdoor air and of indoor settled dust were taken in winter and summer. The results showed that rankings by prevalence and abundance of the types of airborne and dustborne fungi did not differ from winter to summer, nor did these rankings differ when air samples taken indoors were compared with those taken outdoors. Water indicator fungi were essentially absent from both air and dust samples. The air and dust data sets were also examined specifically for the proportions of colonies from ecological groupings such as leaf surface fungi and soil fungi. In the analysis of dust for culturable fungal colonies, leaf surface fungi constituted a considerable portion (>20%) of the total colonies in at least 85% of the samples. Thus, replicate dust samples with less than 20% of colonies from leaf surface fungi are unlikely to be from buildings free of moisture or mold growth problems. PMID:15528497
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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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Fungal biodiversity and mycotoxigenic fungi in cooling-tower water systems in Istanbul, Turkey.
Kadaifciler, Duygu Göksay; Demirel, Rasime
2017-04-01
This is the first study to assess fungal diversity and mycotoxigenic fungi in open recirculating cooling-tower (CT) water systems (biofilm and water phase). The production capability of mycotoxin from fungal isolates was also examined. The mean fungal count in 21 different water and biofilm samples was determined as 234 CFU/100 mL and 4 CFU/cm 2 . A total of 32 species were identified by internal transcribed spacer (ITS) sequencing. The most common isolated fungi belonged to the genera Aspergillus and Penicillium, of which the most prevalent fungi were Aspergillus versicolor, Aspergillus niger, and Penicillium dipodomyicola. From 42% of the surveyed CTs, aflatoxigenic A. flavus isolates were identified. The detection of opportunistic pathogens and/or allergen species suggests that open recirculating CTs are a possible source of fungal infection for both the public and for occupational workers via the inhalation of aerosols and/or skin contact.
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Miller, J D; Haisley, P D; Reinhardt, J H
2000-09-01
We studied the extent and nature of fungal colonization of building materials in 58 naturally ventilated apartments that had suffered various kinds of water damage in relation to air sampling done before the physical inspections. The results of air samples from each apartment were compared by rank order of species with pooled data from outdoor air. Approximately 90% of the apartments that had significant amounts of fungi in wall cavities were identified by air sampling. There was no difference in the average fungal colony forming unit values per m3 between the 15 apartments with the most fungal contamination and the 15 with the least. In contrast, the prevalence of samples with fungal species significantly different than the pooled outdoor air between the more contaminated versus the less contaminated apartments was approximately 10-fold. We provide information on methods to document fungal contamination in buildings.
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Temporal Dynamics of Bacterial and Fungal Colonization on Plastic Debris in the North Sea.
De Tender, Caroline; Devriese, Lisa I; Haegeman, Annelies; Maes, Sara; Vangeyte, Jürgen; Cattrijsse, André; Dawyndt, Peter; Ruttink, Tom
2017-07-05
Despite growing evidence that biofilm formation on plastic debris in the marine environment may be essential for its biodegradation, the underlying processes have yet to be fully understood. Thus, far, bacterial biofilm formation had only been studied after short-term exposure or on floating plastic, yet a prominent share of plastic litter accumulates on the seafloor. In this study, we explored the taxonomic composition of bacterial and fungal communities on polyethylene plastic sheets and dolly ropes during long-term exposure on the seafloor, both at a harbor and an offshore location in the Belgian part of the North Sea. We reconstructed the sequence of events during biofilm formation on plastic in the harbor environment and identified a core bacteriome and subsets of bacterial indicator species for early, intermediate, and late stages of biofilm formation. Additionally, by implementing ITS2 metabarcoding on plastic debris, we identified and characterized for the first time fungal genera on plastic debris. Surprisingly, none of the plastics exposed to offshore conditions displayed the typical signature of a late stage biofilm, suggesting that biofilm formation is severely hampered in the natural environment where most plastic debris accumulates.
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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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Succession of biofilm communities responsible for biofouling of membrane bio-reactors (MBRs)
Luo, Jinxue; Lv, Pengyi; Zhang, Jinsong; Fane, Anthony G.; McDougald, Diane
2017-01-01
Biofilm formation is one of the main factors associated with membrane biofouling in membrane bioreactors (MBRs). As such, it is important to identify the responsible organisms to develop targeted strategies to control biofouling. This study investigated the composition and changes in the microbial communities fouling MBR membranes over time and correlated those changes with an increase in transmembrane pressure (TMP). Based on qPCR data, bacteria were the dominant taxa of the biofilm (92.9–98.4%) relative to fungi (1.5–6.9%) and archaea (0.03–0.07%). NMDS analysis indicated that during the initial stages of operation, the biofilm communities were indistinguishable from those found in the sludge. However, the biofilm community significantly diverged from the sludge over time and ultimately showed a unique biofilm profile. This suggested that there was strong selection for a group of organisms that were biofilm specialists. This pattern of succession and selection was correlated with the rapid increase in TMP, where bacteria including Rhodospirillales, Sphingomonadales and Rhizobiales dominated the biofilm at this time. While most of the identified fungal OTUs matched Candida sp., the majority of fungal communities were unclassified by 18S rRNA gene sequencing. Collectively, the data suggests that bacteria, primarily, along with fungi may play an important role in the rapid TMP increase and loss of system performance. PMID:28686622
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Hashemi, Marjan M; Rovig, John; Holden, Brett S; Taylor, Maddison F; Weber, Scott; Wilson, John; Hilton, Brian; Zaugg, Aaron L; Ellis, Samuel W; Yost, Connor D; Finnegan, Patrick M; Kistler, Charles K; Berkow, Elizabeth L; Deng, Shenglou; Lockhart, Shawn R; Peterson, Marnie; Savage, Paul B
2018-06-01
Candida auris has emerged as a serious threat to human health. Of particular concern are the resistance profiles of many clinical isolates, with some being resistant to multiple classes of antifungals. Measure susceptibilities of C. auris isolates, in planktonic and biofilm forms, to ceragenins (CSAs). Determine the effectiveness of selected ceragenins in gel and cream formulations in eradicating fungal infections in tissue explants. A collection of 100 C. auris isolates available at CDC was screened for susceptibility to a lead ceragenin. A smaller collection was used to characterize antifungal activities of other ceragenins against organisms in planktonic and biofilm forms. Effects of ceragenins on fungal cells and biofilms were observed via microscopy. An ex vivo model of mucosal fungal infection was used to evaluate formulated forms of lead ceragenins. Lead ceragenins displayed activities comparable to those of known antifungal agents against C. auris isolates with MICs of 0.5-8 mg/L and minimum fungicidal concentrations (MFCs) of 2-64 mg/L. No cross-resistance with other antifungals was observed. Fungal cell morphology was altered in response to ceragenin treatment. Ceragenins exhibited activity against sessile organisms in biofilms. Gel and cream formulations including 2% CSA-44 or CSA-131 resulted in reductions of over 4 logs against established fungal infections in ex vivo mucosal tissues. Ceragenins demonstrated activity against C. auris, suggesting that these compounds warrant further study to determine whether they can be used for topical applications to skin and mucosal tissues for treatment of infections with C. auris and other fungi.
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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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Melloul, Elise; Luiggi, Stéphanie; Anaïs, Leslie; Arné, Pascal; Costa, Jean-Marc; Fihman, Vincent; Briard, Benoit; Dannaoui, Eric; Guillot, Jacques; Decousser, Jean-Winoc; Beauvais, Anne; Botterel, Françoise
2016-01-01
Background Biofilms are communal structures of microorganisms that have long been associated with a variety of persistent infections poorly responding to conventional antibiotic or antifungal therapy. Aspergillus fumigatus fungus and Stenotrophomonas maltophilia bacteria are examples of the microorganisms that can coexist to form a biofilm especially in the respiratory tract of immunocompromised patients or cystic fibrosis patients. The aim of the present study was to develop and assess an in vitro model of a mixed biofilm associating S. maltophilia and A. fumigatus by using analytical and quantitative approaches. Materials and Methods An A. fumigatus strain (ATCC 13073) expressing a Green Fluorescent Protein (GFP) and an S. maltophilia strain (ATCC 13637) were used. Fungal and bacterial inocula (105 conidia/mL and 106 cells/mL, respectively) were simultaneously deposited to initiate the development of an in vitro mixed biofilm on polystyrene supports at 37°C for 24 h. The structure of the biofilm was analysed via qualitative microscopic techniques like scanning electron and transmission electron microscopy, and fluorescence microscopy, and by quantitative techniques including qPCR and crystal violet staining. Results Analytic methods revealed typical structures of biofilm with production of an extracellular matrix (ECM) enclosing fungal hyphae and bacteria. Quantitative methods showed a decrease of A. fumigatus growth and ECM production in the mixed biofilm with antibiosis effect of the bacteria on the fungi seen as abortive hyphae, limited hyphal growth, fewer conidia, and thicker fungal cell walls. Conclusion For the first time, a mixed A. fumigatus—S. maltophilia biofilm was validated by various analytical and quantitative approaches and the bacterial antibiosis effect on the fungus was demonstrated. The mixed biofilm model is an interesting experimentation field to evaluate efficiency of antimicrobial agents and to analyse the interactions between the
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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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Combinatorial drug approaches to tackle Candida albicans biofilms.
De Cremer, Kaat; Staes, Ines; Delattin, Nicolas; Cammue, Bruno P A; Thevissen, Karin; De Brucker, Katrijn
2015-08-01
The human fungal opportunistic pathogen Candida albicans resides in the human gut, genitourinary tract and on the skin. The majority of infections caused by C. albicans are biofilm-related. In the first part of this review, we discuss new insights into C. albicans biofilm characteristics, concentrating on the extracellular matrix, phenotypic switching, efflux pumps and persister cells. It is widely accepted that this multicellular lifestyle is more resistant to traditional antifungal treatment compared to free-living cells. Therefore, much effort is put in the search for combinations of drugs leading to synergistic interactions against microbial biofilms to achieve lower effective doses of the drugs. In the second part of this manuscript, we review all recently identified compounds that act synergistically with azoles, echinocandins and/or polyenes against C. albicans biofilms.
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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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Miltefosine is effective against Candida albicans and Fusarium oxysporum nail biofilms in vitro.
Machado Vila, Taissa Vieira; Sousa Quintanilha, Natália; Rozental, Sonia
2015-11-01
Onychomycosis is a fungal nail infection that represents ∼50 % of all nail disease cases worldwide. Clinical treatment with standard antifungals frequently requires long-term systemic therapy to avoid chronic disease. Onychomycosis caused by non-dermatophyte moulds, such as Fusarium spp., and yeasts, such as Candida spp., is particularly difficult to treat, possibly due to the formation of drug-resistant fungal biofilms on affected areas. Here, we show that the alkylphospholipid miltefosine, used clinically against leishmaniasis and cutaneous breast metastases, has potent activity against biofilms of Fusarium oxysporum and Candida albicans formed on human nail fragments in vitro. Miltefosine activity was compared with that of commercially available antifungals in the treatment of biofilms at two distinct developmental phases: formation and maturation (pre-formed biofilms). Drug activity towards biofilms formed on nail fragments and on microplate surfaces (microdilution assays) was evaluated using XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] assays, and drug effects on fingernail biofilms were analysed by scanning electron microscopy (SEM). For F. oxysporum, miltefosine at 8 μg ml- 1 inhibited biofilm formation by 93%, whilst 256 μg ml- 1 reduced the metabolic activity of pre-formed nail biofilms by 93%. Treatment with miltefosine at 1000 μg ml- 1 inhibited biofilm formation by 89% and reduced the metabolic activity of pre-formed C. albicans biofilms by 99%. SEM analyses of biofilms formed on fingernail fragments showed a clear reduction in biofilm biomass after miltefosine treatment, in agreement with XTT results. Our results show that miltefosine has potential as a therapeutic agent against onychomycosis and should be considered for in vivo efficacy studies, especially in topical formulations for refractory disease treatment.
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[Susceptibility to antifungal agents of Candida sp. and biofilm formation].
Ciok-Pater, Emilia; Białucha, Agata; Gospodarek, Eugenia; Ostafin, Agnieszka
2011-01-01
In recent years the increase in frequency of fungal infections with Candida sp. was noticed. These infections are connected with ability of Candida sp. to form biofilm on surfaces of biomaterials used in medicine. Furthermore fungal infections make serious therapeutic problems because ofbiofilm resistance to antifungal agents actually. The aim of the study was to evaluate the susceptibility to antifungal agents of Candida sp. and their ability to form biofilm on different biomaterials. 50 strains of Candida sp. isolated from patients of University Hospital No. 1 of dr A. Jurasz in Bydgoszcz were examined. API Candida (bioMérieux) tests were used to identify Candida sp. strains. The susceptibility of the yeast strains to antifungal agents was evaluated by ATB FUNGUS 2 INT (bioMérieux) tests. The susceptibility of examined strains to voriconazole, posaconazole, caspofungin and anidulafungin was assessed by means ofEtests (AB BIODISK) method employing drug concentrations from 0,002 to 32 microg/ml. All analysed strains were susceptible to amphotericin B and caspofungin. Biofilm formation on different biomaterials (silicon, latex, polychloride vinyl, polypropylene, nylon) was measured after 72 hour incubation at 37 degrees C. All examined yeasts formed biofilm on all analysed biomaterials. The highest number of strains formed biofilm on surface of polychloride vinyl: 23 (92,0%) by C. albicans strains and 24 (96,0%) Candida non-albicans strains. The lowest number of the strains formed biofilm on the surface of nylon: 12 (48,0%) of C. albicans strains and 9 (36,0%) of Candida non-albicans strains. The studied strains resistant to azoles and anidulafungin display stronger ability to form biofilm on surfaces of all analysed biomaterials.
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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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In situ rheology of yeast biofilms.
Brugnoni, Lorena I; Tarifa, María C; Lozano, Jorge E; Genovese, Diego
2014-01-01
The aim of the present work was to investigate the in situ rheological behavior of yeast biofilms growing on stainless steel under static and turbulent flow. The species used (Rhodototula mucilaginosa, Candida krusei, Candida kefyr and Candida tropicalis) were isolated from a clarified apple juice industry. The flow conditions impacted biofilm composition over time, with a predominance of C. krusei under static and turbulent flow. Likewise, structural variations occurred, with a tighter appearance under dynamic flow. Under turbulent flow there was an increase of 112 μm in biofilm thickness at 11 weeks (p < 0.001) and cell morphology was governed by hyphal structures and rounded cells. Using the in situ growth method introduced here, yeast biofilms were determined to be viscoelastic materials with a predominantly solid-like behavior, and neither this nor the G'0 values were significantly affected by the flow conditions or the growth time, and at large deformations their weak structure collapsed beyond a critical strain of about 1.5-5%. The present work could represent a starting point for developing in situ measurements of yeast rheology and contribute to a thin body of knowledge about fungal biofilm formation.
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Kalan, Lindsay; Loesche, Michael; Hodkinson, Brendan P.; Heilmann, Kristopher; Ruthel, Gordon
2016-01-01
ABSTRACT Chronic nonhealing wounds have been heralded as a silent epidemic, causing significant morbidity and mortality especially in elderly, diabetic, and obese populations. Polymicrobial biofilms in the wound bed are hypothesized to disrupt the highly coordinated and sequential events of cutaneous healing. Both culture-dependent and -independent studies of the chronic-wound microbiome have almost exclusively focused on bacteria, omitting what we hypothesize are important fungal contributions to impaired healing and the development of complications. Here we show for the first time that fungal communities (the mycobiome) in chronic wounds are predictive of healing time, associated with poor outcomes, and form mixed fungal-bacterial biofilms. We longitudinally profiled 100, nonhealing diabetic-foot ulcers with high-throughput sequencing of the pan-fungal internal transcribed spacer 1 (ITS1) locus, estimating that up to 80% of wounds contain fungi, whereas cultures performed in parallel captured only 5% of colonized wounds. The “mycobiome” was highly heterogeneous over time and between subjects. Fungal diversity increased with antibiotic administration and onset of a clinical complication. The proportions of the phylum Ascomycota were significantly greater (P = 0.015) at the beginning of the study in wounds that took >8 weeks to heal. Wound necrosis was distinctly associated with pathogenic fungal species, while taxa identified as allergenic filamentous fungi were associated with low levels of systemic inflammation. Directed culturing of wounds stably colonized by pathogens revealed that interkingdom biofilms formed between yeasts and coisolated bacteria. Combined, our analyses provide enhanced resolution of the mycobiome during impaired wound healing, its role in chronic disease, and impact on clinical outcomes. PMID:27601572
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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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Proteomics of drug resistance in Candida glabrata biofilms.
Seneviratne, C Jayampath; Wang, Yu; Jin, Lijian; Abiko, Y; Samaranayake, Lakshman P
2010-04-01
Candida glabrata is a fungal pathogen that causes a variety of mucosal and systemic infections among compromised patient populations with higher mortality rates. Previous studies have shown that biofilm mode of the growth of the fungus is highly resistant to antifungal agents compared with the free-floating or planktonic mode of growth. Therefore, in the present study, we used 2-D DIGE to evaluate the differential proteomic profiles of C. glabrata under planktonic and biofilm modes of growth. Candida glabrata biofilms were developed on polystyrene surfaces and age-matched planktonic cultures were obtained in parallel. Initially, biofilm architecture, viability, and antifungal susceptibility were evaluated. Differentially expressed proteins more than 1.5-fold in DIGE analysis were subjected to MS/MS. The transcriptomic regulation of these biomarkers was evaluated by quantitative real-time PCR. Candida glabrata biofilms were highly resistant to the antifungals and biocides compared with the planktonic mode of growth. Candida glabrata biofilm proteome when compared with its planktonic proteome showed upregulation of stress response proteins, while glycolysis enzymes were downregulated. Similar trend could be observed at transcriptomic level. In conclusion, C. glabrata biofilms possess higher amount of stress response proteins, which may potentially contribute to the higher antifungal resistance seen in C. glabrata biofilms.
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Kadry, Ashraf A; El-Ganiny, Amira M; Mosbah, Rasha A; Kaminskyj, Susan G W
2018-07-01
Systemic human fungal infections are increasingly common. Aspergillus species cause most of the airborne fungal infections. Life-threatening invasive aspergillosis was formerly found only in immune-suppressed patients, but recently some strains of A. fumigatus have become primary pathogens. Many fungal cell wall components are absent from mammalian systems, so they are potential drug targets. Cell-wall-targeting drugs such as echinocandins are used clinically, although echinocandin-resistant strains were discovered shortly after their introduction. Currently there are no fully effective anti-fungal drugs. Fungal cell wall glycoconjugates modulate human immune responses, as well as fungal cell adhesion, biofilm formation, and drug resistance. Guanosine diphosphate (GDP) mannose transporters (GMTs) transfer GDP-mannose from the cytosol to the Golgi lumen prior to mannosylation. Aspergillus nidulans GMTs are encoded by gmtA and gmtB. Here we elucidate the roles of A. nidulans GMTs. Strains engineered to lack either or both GMTs were assessed for hyphal and colonial morphology, cell wall ultrastructure, antifungal susceptibility, spore hydrophobicity, adherence and biofilm formation. The gmt-deleted strains had smaller colonies with reduced sporulation and with thicker hyphal walls. The gmtA deficient spores had reduced hydrophobicity and were less adherent and less able to form biofilms in vitro. Thus, gmtA not only participates in maintaining the cell wall integrity but also plays an important role in biofilm establishment and adherence of A. nidulans. These findings suggested that GMTs have roles in A. nidulans growth and cell-cell interaction and could be a potential target for new antifungals that target virulence determinants.
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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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Simitsopoulou, Maria; Peshkova, Pavla; Tasina, Efthymia; Katragkou, Aspasia; Kyrpitzi, Daniela; Velegraki, Aristea; Walsh, Thomas J.
2013-01-01
Candida species other than Candida albicans are increasingly recognized as causes of biofilm-associated infections. This is a comprehensive study that compared the in vitro activities of all three echinocandins against biofilms formed by different common and infrequently identified Candida isolates. We determined the activities of anidulafungin (ANID), caspofungin (CAS), and micafungin (MFG) against planktonic cells and biofilms of bloodstream isolates of C. albicans (15 strains), Candida parapsilosis (6 strains), Candida lusitaniae (16 strains), Candida guilliermondii (5 strains), and Candida krusei (12 strains) by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] assay. Planktonic and biofilm MICs were defined as ≥50% fungal damage. Planktonic cells of all Candida species were susceptible to the three echinocandins, with MICs of ≤1 mg/liter. By comparison, differences in the MIC profiles of biofilms in response to echinocandins existed among the Candida species. Thus, C. lusitaniae and C. guilliermondii biofilms were highly recalcitrant to all echinocandins, with MICs of ≥32 mg/liter. In contrast, the MICs of all three echinocandins for C. albicans and C. krusei biofilms were relatively low (MICs ≤ 1 mg/liter). While echinocandins exhibited generally high MICs against C. parapsilosis biofilms, MFG exhibited the lowest MICs against these isolates (4 mg/liter). A paradoxical growth effect was observed with CAS concentrations ranging from 8 to 64 mg/liter against C. albicans and C. parapsilosis biofilms but not against C. krusei, C. lusitaniae, or C. guilliermondii. While non-albicans Candida planktonic cells were susceptible to all echinocandins, there were drug- and species-specific differences in susceptibility among biofilms of the various Candida species, with C. lusitaniae and C. guilliermondii exhibiting profiles of high MICs of the three echinocandins. PMID:23529739
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Planktonic growth and biofilm formation profiles in Candida haemulonii species complex.
Ramos, Lívia S; Oliveira, Simone S C; Souto, Xênia M; Branquinha, Marta H; Santos, André L S
2017-10-01
Candida haemulonii species complex have emerged as multidrug-resistant yeasts able to cause fungemia worldwide. However, very little is known regarding their physiology and virulence factors. In this context, planktonic growth and biofilm formation of Brazilian clinical isolates of Candida haemulonii (n = 5), Candida duobushaemulonii (n = 4), and Candida haemulonii var. vulnera (n = 3) were reported. Overall, the fungal planktonic growth curves in Sabouraud dextrose broth reached the exponential phase in 48 h at 37°C. All the clinical isolates formed biofilm on polystyrene in a time-dependent event, as judged by the parameters evaluated: biomass (crystal violet staining), metabolic activity (XTT reduction), and extracellular matrix (safranin incorporation). No statistically significant differences were observed when the average measurements among the three Candida species were compared regarding both planktonic and biofilm lifestyles; however, typical isolate-specific differences were clearly noticed in fungal growth kinetics. © The Author 2017. 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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Keratitis-associated fungi form biofilms with reduced antifungal drug susceptibility.
Zhang, Xiaoyan; Sun, Xuguang; Wang, Zhiqun; Zhang, Yang; Hou, Wenbo
2012-11-21
To investigate the biofilm-forming capacity of Fusarium solani, Cladosporium sphaerospermum, and Acremonium implicatum, and the activities of antifungal agents against the three keratitis-associated fungi. The architecture of biofilms was analyzed using scanning electron microscopy and confocal scanning laser microscopy (CSLM). Susceptibility against six antifungal drugs was measured using the CLSI M38-A method and XTT reduction assay. Time course analyses of CSLM revealed that biofilm formation occurred in an organized fashion through four distinct developmental phases: adhesion, germling formation, microcolony formation, and biofilm maturation. Scanning electron microscopy revealed that mature biofilms displayed a complex three-dimensional structure, consisting of coordinated network of hyphal structures glued by the extracellular matrix (ECM). The antifungal susceptibility testing demonstrated a time-dependent decrease in efficacy for all six antifungal agents as the complexity of fungal hyphal structures developed. Natamycin (NAT), amphotericin B (AMB), and NAT were the most effective against F. solani, C. sphaerospermum, and A. implicatum biofilm, respectively. Corneal isolates of F. solani, C. sphaerospermum, and A. implicatum could produce biofilms that were resistant to antifungal agents in vitro.
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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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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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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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Kong, Jin-Liang; Luo, Jing; Li, Bing; Dong, Bi-Ying; Huang, Hong; Wang, Ke; Wu, Li-Hong; Chen, Yi-Qiang
2017-06-01
Aspergillus ( A .) fumigatus , one of the most common causes of life-threatening fungal infections in immunocompromised patients, shows resistance to antifungal agents as has a high propensity to forming a biofilm. The present study aimed to investigate the effects of chlorogenic acid (CRA) on A. fumigatus biofilm formation and integrity. Confocal laser scanning microscopy was performed to determine the inhibitory effects of CRA against A. fumigatus biofilm formation. Transmission electron microscopy was performed to investigate the ultrastructural changes of A. fumigatus biofilm after CRA exposure. High-performance liquid chromatography and reverse-transcription quantitative PCR were performed to determine the expression of gliotoxin production in biofilm culture. The results showed that CRA at sub-minimum inhibitory concentrations inhibited A. fumigatus biofilm formation. In addition, CRA could decreased the gliotoxin production in the biofilm culture supernatant through inhibiting the expression of master genes involved in gliotoxin biosynthesis. The present study provided useful information for the development of novel strategies to reduce the incidence of A. fumigatus biofilm-associated diseases.
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Dranguet, P; Cosio, C; Le Faucheur, S; Hug Peter, D; Loizeau, J-L; Ungureanu, V-Gh; Slaveykova, V I
2017-05-24
Freshwater biofilms can be useful indicators of water quality and offer the possibility to assess contaminant effects at the community level. The present field study examines the effects of chlor-alkali plant effluents on the community composition of biofilms grown in the Olt River (Romania) reservoirs. The relationship between ambient water quality variables and community composition alterations was explored. Amplicon sequencing revealed a significant modification of the composition of microalgal, bacterial and fungal communities in the biofilms collected in the impacted reservoirs in comparison with those living in the uncontaminated control reservoir. The abundance corrected Simpson index showed lower richness and diversity in biofilms collected in the impacted reservoirs than in the control reservoir. The biofilm bacterial communities of the impacted reservoirs were characterized by the contaminant-tolerant Cyanobacteria and Bacteroidetes, whereas microalgal communities were predominantly composed of Bacillariophyta and fungal communities of Lecanoromycetes and Paraglomycetes. A principal component analysis revealed that major contaminants present in the waste water of the chlor-alkali production plant, i.e. Na + , Ca 2+ , Cl - and Hg, were correlated with the alteration of biofilm community composition in the impacted reservoirs. However, the biofilm composition was also influenced by water quality variables such as NO 3 - , SO 4 2- , DOC and Zn from unknown sources. The results of the present study imply that, even when below the environmental quality standards, typical contaminants of chlor-alkali plant releases may affect biofilm composition and that their impacts on the microbial biodiversity might be currently overlooked.
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Plasma membrane lipids and their role in fungal virulence.
Rella, Antonella; Farnoud, Amir M; Del Poeta, Maurizio
2016-01-01
There has been considerable evidence in recent years suggesting that plasma membrane lipids are important regulators of fungal pathogenicity. Various glycolipids have been shown to impart virulent properties in several fungal species, while others have been shown to play a role in host defense. In addition to their role as virulence factors, lipids also contribute to other virulence mechanisms such as drug resistance, biofilm formation, and release of extracellular vesicles. In addition, lipids also affect the mechanical properties of the plasma membrane through the formation of packed microdomains composed mainly of sphingolipids and sterols. Changes in the composition of lipid microdomains have been shown to disrupt the localization of virulence factors and affect fungal pathogenicity. This review gathers evidence on the various roles of plasma membrane lipids in fungal virulence and how lipids might contribute to the different processes that occur during infection and treatment. Insight into the role of lipids in fungal virulence can lead to an improved understanding of the process of fungal pathogenesis and the development of new lipid-mediated therapeutic strategies. Published by Elsevier Ltd.
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Unraveling the resistance of microbial biofilms: has proteomics been helpful?
Seneviratne, C Jayampath; Wang, Yu; Jin, Lijian; Wong, Sarah S W; Herath, Thanuja D K; Samaranayake, Lakshman P
2012-02-01
Biofilms are surface-attached, matrix-encased, structured microbial communities which display phenotypic features that are dramatically different from those of their free-floating, or planktonic, counterparts. Biofilms seem to be the preferred mode of growth of microorganisms in nature, and at least 65% of all human infections are associated with biofilms. The most notable and clinically relevant property of biofilms is their greater resistance to antimicrobials compared with their planktonic counterparts. Although both bacterial and fungal biofilms display this phenotypic feature, the exact mechanisms underlying their increased drug resistance are yet to be determined. Advances in proteomics techniques during the past decade have facilitated in-depth analysis of the possible mechanisms underpinning increased drug resistance in biofilms. These studies have demonstrated the ability of proteomics techniques to unravel new targets for combating microbial biofilms. In this review, we discuss the putative drug resistance mechanisms of microbial biofilms that have been uncovered by proteomics and critically evaluate the possible contribution of the new knowledge to future development in the field. We also summarize strategic uses of novel proteomics technologies in studies related to drug resistance mechanisms of microbial biofilms. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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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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Hwang, Geelsu; Liu, Yuan; Kim, Dongyeop; Li, Yong; Krysan, Damian J; Koo, Hyun
2017-06-01
Candida albicans is frequently detected with heavy infection by Streptococcus mutans in plaque-biofilms from children with early-childhood caries (ECC). This cross-kingdom biofilm contains an extensive matrix of extracellular α-glucans that is produced by an exoenzyme (GtfB) secreted by S. mutans. Here, we report that mannans located on the outer surface of C. albicans cell-wall mediates GtfB binding, enhancing glucan-matrix production and modulating bacterial-fungal association within biofilms formed in vivo. Using single-molecule atomic force microscopy, we determined that GtfB binds with remarkable affinity to mannans and to the C. albicans surface, forming a highly stable and strong bond (1-2 nN). However, GtfB binding properties to C. albicans was compromised in strains defective in O-mannan (pmt4ΔΔ) or N-mannan outer chain (och1ΔΔ). In particular, the binding strength of GtfB on och1ΔΔ strain was severely disrupted (>3-fold reduction vs. parental strain). In turn, the GtfB amount on the fungal surface was significantly reduced, and the ability of C. albicans mutant strains to develop mixed-species biofilms with S. mutans was impaired. This phenotype was independent of hyphae or established fungal-biofilm regulators (EFG1, BCR1). Notably, the mechanical stability of the defective biofilms was weakened, resulting in near complete biomass removal by shear forces. In addition, these in vitro findings were confirmed in vivo using a rodent biofilm model. Specifically, we observed that C. albicans och1ΔΔ was unable to form cross-kingdom biofilms on the tooth surface of rats co-infected with S. mutans. Likewise, co-infection with S. mutans defective in GtfB was also incapable of forming mixed-species biofilms. Taken together, the data support a mechanism whereby S. mutans-secreted GtfB binds to the mannan layer of C. albicans to promote extracellular matrix formation and their co-existence within biofilms. Enhanced understanding of GtfB-Candida interactions
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Effect of Voriconazole on Candida tropicalis Biofilms: Relation with ERG Genes Expression.
Fernandes, Tânia; Silva, Sónia; Henriques, Mariana
2016-10-01
Candida tropicalis has emerged as the third most prevalent fungal pathogens and its ability to form biofilms has been considered one of the most important virulence factors, since biofilms represent high tolerance to antifungal agents. However, the mechanisms of C. tropicalis biofilm resistance to antifungals remain poorly understood. Thus, the main aim of this work was to infer about the effect of voriconazole on the formation and control of C. tropicalis biofilms and disclose its relationship with ERG genes' expression. Planktonic cells tolerance of several C. tropicalis clinical isolates to voriconazole was determined through of antifungal susceptibility test, and the effect of this azole against C. tropicalis biofilm formation and pre-formed biofilms was evaluated by cultivable cells determination and total biomass quantification. ERG genes expression was analyzed by quantitative real-time polymerase chain reaction. This work showed that C. tropicalis resistance to voriconazole is strain dependent and that voriconazole was able to partially control biofilm formation, but was unable to eradicate C. tropicalis pre-formed biofilms. Moreover, C. tropicalis biofilms resistance to voriconazole seems to be associated with alterations of sterol content in the cell membrane, resulting in ERG genes overexpression. Voriconazole is unable to control C. tropicalis biofilms, and the overexpression of ERG genes is a possible mechanism of biofilm resistance.
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Falsetta, Megan L.; Klein, Marlise I.; Colonne, Punsiri M.; Scott-Anne, Kathleen; Gregoire, Stacy; Pai, Chia-Hua; Gonzalez-Begne, Mireya; Watson, Gene; Krysan, Damian J.; Bowen, William H.
2014-01-01
Streptococcus mutans is often cited as the main bacterial pathogen in dental caries, particularly in early-childhood caries (ECC). S. mutans may not act alone; Candida albicans cells are frequently detected along with heavy infection by S. mutans in plaque biofilms from ECC-affected children. It remains to be elucidated whether this association is involved in the enhancement of biofilm virulence. We showed that the ability of these organisms together to form biofilms is enhanced in vitro and in vivo. The presence of C. albicans augments the production of exopolysaccharides (EPS), such that cospecies biofilms accrue more biomass and harbor more viable S. mutans cells than single-species biofilms. The resulting 3-dimensional biofilm architecture displays sizeable S. mutans microcolonies surrounded by fungal cells, which are enmeshed in a dense EPS-rich matrix. Using a rodent model, we explored the implications of this cross-kingdom interaction for the pathogenesis of dental caries. Coinfected animals displayed higher levels of infection and microbial carriage within plaque biofilms than animals infected with either species alone. Furthermore, coinfection synergistically enhanced biofilm virulence, leading to aggressive onset of the disease with rampant carious lesions. Our in vitro data also revealed that glucosyltransferase-derived EPS is a key mediator of cospecies biofilm development and that coexistence with C. albicans induces the expression of virulence genes in S. mutans (e.g., gtfB, fabM). We also found that Candida-derived β1,3-glucans contribute to the EPS matrix structure, while fungal mannan and β-glucan provide sites for GtfB binding and activity. Altogether, we demonstrate a novel mutualistic bacterium-fungus relationship that occurs at a clinically relevant site to amplify the severity of a ubiquitous infectious disease. PMID:24566629
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NASA Astrophysics Data System (ADS)
Lamont-Friedrich, Stephanie J.; Michl, Thomas D.; Giles, Carla; Griesser, Hans J.; Coad, Bryan R.
2016-07-01
The attachment of pathogenic fungal cells onto materials surfaces, which is often followed by biofilm formation, causes adverse consequences in a wide range of areas. Here we have investigated the ability of thin film coatings from chlorinated molecules to deter fungal colonization of solid materials by contact killing of fungal cells reaching the surface of the coating. Coatings were deposited onto various substrate materials via plasma polymerization, which is a substrate-independent process widely used for industrial coating applications, using 1,1,2-trichloroethane as the process vapour. XPS surface analysis showed that the coatings were characterized by a highly chlorinated hydrocarbon polymer nature, with only a very small amount of oxygen incorporated. The activity of these coatings against human fungal pathogens was quantified using a recently developed, modified yeast assay and excellent antifungal activity was observed against Candida albicans and Candida glabrata. Plasma polymer surface coatings derived from chlorinated hydrocarbon molecules may therefore offer a promising solution to preventing yeast and mould biofilm formation on materials surfaces, for applications such as air conditioners, biomedical devices, food processing equipment, and others.
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Raman, Namrata; Lee, Myung-Ryul; Rodríguez López, Angélica de L; Palecek, Sean P; Lynn, David M
2016-10-01
Catheter-associated urinary tract infections (CAUTI) are the most common type of hospital-acquired infection, with more than 30 million catheters placed annually in the US and a 10-30% incidence of infection. Candida albicans forms fungal biofilms on the surfaces of urinary catheters and is the leading cause of fungal urinary tract infections. As a step toward new strategies that could prevent or reduce the occurrence of C. albicans-based CAUTI, we investigated the ability of antifungal β-peptide-based mimetics of antimicrobial peptides (AMPs) to kill C. albicans and prevent biofilm formation in synthetic urine. Many α-peptide-based AMPs exhibit antifungal activities, but are unstable in high ionic strength media and are easily degraded by proteases-features that limit their use in urinary catheter applications. Here, we demonstrate that β-peptides designed to mimic the amphiphilic helical structures of AMPs retain 100% of their structural stability and exhibit antifungal and anti-biofilm activity against C. albicans in a synthetic medium that mimics the composition of urine. We demonstrate further that these agents can be loaded into and released from polymer-based multilayer coatings applied to polyurethane, polyethylene, and silicone tubing commonly used as urinary catheters. Our results reveal catheters coated with β-peptide-loaded multilayers to kill planktonic fungal cells for up to 21days of intermittent challenges with C. albicans and prevent biofilm formation on catheter walls for at least 48h. These new materials and approaches could lead to advances that reduce the occurrence of fungal CAUTI. Catheter-associated urinary tract infections are the most common type of hospital-acquired infection. The human pathogen Candida albicans is the leading cause of fungal urinary tract infections, and forms difficult to remove 'biofilms' on the surfaces of urinary catheters. We investigated synthetic β-peptide mimics of natural antimicrobial peptides as an
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Kackar, Siddharth; Suman, Ethel; Kotian, M Shashidhar
2017-01-01
Microbial biofilm formation on contact lenses and lens storage cases may be a risk factor for contact lens-associated corneal infections. Various types of contact lens care solutions are used to reduce microbial growths on lenses. The present study aimed at comparing the growths of biofilms on the different contact lenses and lens cases. The study also aimed at determining the effect of lens care solutions and bacteriophage on these biofilms. One type of hard lens and two types of soft lenses were used for the study. The organisms used were Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 60193 and Escherichia coli ATCC 25922. Biofilm production was performed by modified O'Toole and Kolter method and effect of lens cleaning solutions and a crude coliphage on biofilms was also studied. Results were visualised using scanning electron microscopy and quantitated by colony counting method and spectrophotometric measurement of optical density (OD). Statistical analysis was done by SPSS 11.5, Kruskal-Wallis test and Chi-square test. Soft lens cleaning solutions had a significant inhibitory effect (P = 0.020) on biofilm formation on soft lenses and also lens cases (P < 0.001). Soft lens cleaning solution 2 was more efficient than solution 1. However, no such inhibitory effect was observed with regard to hard lens cleaning solution, but for a significant reduction in the OD values (P < 0.001). There was no significant inhibitory effect by bacteriophages. This study showed the importance of selecting the appropriate lens cleaning solution to prevent biofilm production on contact lenses.
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POSSIBLE ROLE OF FUNGAL HEMOLYSINS IN SICK BUILDING SYNDROME
Many fungi produce proteinaceous hemolytic agents. Like bacterial hemolysins, fungal hemolysins create pores or holes in membranes. Depending on which membranes are damaged, fungal hemolysins can produce a variety of effects. Fungal hemolysins can cause histamine release from ...
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Krzyściak, Wirginia; Kościelniak, Dorota; Papież, Monika; Vyhouskaya, Palina; Zagórska-Świeży, Katarzyna; Kołodziej, Iwona; Bystrowska, Beata; Jurczak, Anna
2017-11-14
The aim of the study was to evaluate the anti-cariogenic effects of Lactobacillus salivarius by reducing pathogenic species and biofilm mass in a double-species biofilm model. Coexistence of S. mutans with C. albicans can cause dental caries progression or recurrence of the disease in the future. Fifty-nine children with diagnosed early childhood caries (ECC) were recruited onto the study. The condition of the children's dentition was defined according to the World Health Organization guidelines. The participants were divided into children with initial enamel demineralization and children showing dentin damage. The study was performed on the S. mutans and C. albicans clinical strains, isolated from dental plaque of patients with ECC. The effect of a probiotic containing Lactobacillus salivarius on the ability of S. mutans and C. albicans to produce a double-species biofilm was investigated in an in vitro model. The biomass of the formed/non-degraded biofilm was analyzed on the basis of its crystal violet staining. The number of colonies of S. mutans and C. albicans (CFU/mL, colony forming units/mL) forming the biofilm was determined. Microorganism morphology in the biofilm was evaluated using a scanning electron microscope (SEM). In vitro analysis demonstrated that the presence of S. mutans increased the number of C. albicans colonies (CFU/mL); the double-species biofilm mass and hyphal forms produced in it by the yeast. L. salivarius inhibited the cariogenic biofilm formation of C. albicans and S. mutans . Under the influence of the probiotic; the biofilm mass and the number of S. mutans ; C. albicans and S. mutans with C. albicans colonies in the biofilm was decreased. Moreover; it can be noted that after the addition of the probiotic; fungi did not form hyphae or germ tubes of pathogenic potential. These results suggest that L. salivarius can secrete intermediates capable of inhibiting the formation of cariogenic S. mutans and C. albicans biofilm; and may
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Dynamics of Mixed- Candida Species Biofilms in Response to Antifungals.
Vipulanandan, G; Herrera, M; Wiederhold, N P; Li, X; Mintz, J; Wickes, B L; Kadosh, D
2018-01-01
Oral infections caused by Candida species, the most commonly isolated human fungal pathogen, are frequently associated with biofilms. Although Candida albicans is the predominant organism found in patients with oral thrush, a biofilm infection, there is an increasing incidence of oral colonization and infections caused by non- albicans Candida species, including C. glabrata, C. dubliniensis, and C. tropicalis, which are frequently more resistant to antifungal treatment. While single-species Candida biofilms have been well studied, considerably less is known about the dynamics of mixed- Candida species biofilms and how these dynamics are altered by antifungal treatment. To address these questions, we developed a quantitative polymerase chain reaction-based approach to determine the precise species composition of mixed- Candida species biofilms formed by clinical isolates and laboratory strains in the presence and absence of clinically relevant concentrations of 3 commonly used antifungals: fluconazole, caspofungin, and amphotericin B. In monospecies biofilms, fluconazole exposure favored growth of C. glabrata and C. tropicalis, while caspofungin generally favored significant growth of all species to a varying degree. Fluconazole was not effective against preformed mixed- Candida species biofilms while amphotericin B was potent. As a general trend, in mixed- Candida species biofilms, C. albicans lost dominance in the presence of antifungals. Interestingly, presence in mixed versus monospecies biofilms reduced susceptibility to amphotericin B for C. tropicalis and C. glabrata. Overall, our data suggest that antifungal treatment favors the growth of specific non- albicans Candida species in mixed- Candida species biofilms.
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Zupančič, Jerneja; Raghupathi, Prem K; Houf, Kurt; Burmølle, Mette; Sørensen, Søren J; Gunde-Cimerman, Nina
2018-01-01
Biofilms formed on rubber seals in dishwashers harbor diverse microbiota. In this study, we focussed on the microbial composition of bacteria and fungi, isolated from a defined area of one square centimeter of rubber from four domestic dishwashers and assessed their abilities to in vitro multispecies biofilm formation. A total of 80 isolates (64 bacterial and 16 fungal) were analyzed. Multiple combinations of bacterial isolates from each dishwasher were screened for synergistic interactions. 32 out of 140 tested (23%) four-species bacterial combinations displayed consistent synergism leading to an overall increase in biomass, in all experimental trails. Bacterial isolates from two of the four dishwashers generated a high number of synergistically interacting four-species consortia. Network based correlation analyses also showed higher co-occurrence patterns observed between bacterial members in the same two dishwasher samples, indicating cooperative effects. Furthermore, two synergistic four-species bacterial consortia were tested for their abilities to incorporate an opportunistic fungal pathogen, Exophiala dermatitidis and their establishment as biofilms on sterile ethylene propylene diene monomer M-class (EPDM) rubber and polypropylene (PP) surfaces. When the bacterial consortia included E. dermatitidis , the overall cell numbers of both bacteria and fungi increased and a substantial increase in biofilm biomass was observed. These results indicate a novel phenomenon of cross kingdom synergy in biofilm formation and these observations could have potential implications for human health.
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Zupančič, Jerneja; Raghupathi, Prem K.; Houf, Kurt; Burmølle, Mette; Sørensen, Søren J.; Gunde-Cimerman, Nina
2018-01-01
Biofilms formed on rubber seals in dishwashers harbor diverse microbiota. In this study, we focussed on the microbial composition of bacteria and fungi, isolated from a defined area of one square centimeter of rubber from four domestic dishwashers and assessed their abilities to in vitro multispecies biofilm formation. A total of 80 isolates (64 bacterial and 16 fungal) were analyzed. Multiple combinations of bacterial isolates from each dishwasher were screened for synergistic interactions. 32 out of 140 tested (23%) four-species bacterial combinations displayed consistent synergism leading to an overall increase in biomass, in all experimental trails. Bacterial isolates from two of the four dishwashers generated a high number of synergistically interacting four-species consortia. Network based correlation analyses also showed higher co-occurrence patterns observed between bacterial members in the same two dishwasher samples, indicating cooperative effects. Furthermore, two synergistic four-species bacterial consortia were tested for their abilities to incorporate an opportunistic fungal pathogen, Exophiala dermatitidis and their establishment as biofilms on sterile ethylene propylene diene monomer M-class (EPDM) rubber and polypropylene (PP) surfaces. When the bacterial consortia included E. dermatitidis, the overall cell numbers of both bacteria and fungi increased and a substantial increase in biofilm biomass was observed. These results indicate a novel phenomenon of cross kingdom synergy in biofilm formation and these observations could have potential implications for human health. PMID:29441043
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Zeng, Guisheng; Qingsong, Lin; Kwang, Lim Teck; Tong, Cao; Chan, Fong Yee; Wang, Yue; Seneviratne, Chaminda Jayampath
2016-01-01
Candida albicans is a major fungal pathogen causing lethal infections in immunocompromised patients. C. albicans forms antifungal tolerant biofilms contributing significantly to therapeutic failure. The recently established haploid C. albicans biofilm model provides a new toolbox to uncover the mechanism governing the higher antifungal tolerance of biofilms. Here, we comprehensively examined the proteomics and antifungal susceptibility of standard diploid (SC5314 and BWP17) and stable haploid (GZY792 and GZY803) strains of C. albicans biofilms. Subsequent downstream analyses identified alkyl hydroperoxide reductase 1 (AHP1) as a critical determinant of C. albicans biofilm's tolerance of amphotericin B. At 32 μg/ml of amphotericin B, GZY803 haploid biofilms showed 0.1% of persister population as compared with 1% of the diploid biofilms. AHP1 expression was found to be lower in GZY803 biofilms, and AHP1 overexpression in GZY803 restored the percentage of persister population. Consistently, deleting AHP1 in the diploid strain BWP17 caused a similar increase in amphotericin B susceptibility. AHP1 expression was also positively correlated with the antioxidant potential. Furthermore, C. albicans ira2Δ/Δ biofilms were susceptible to amphotericin B and had a diminished antioxidant capacity. Interestingly, AHP1 overexpression in the ira2Δ/Δ strain restored the antioxidant potential and enhanced the persister population against amphotericin B, and shutting down the AHP1 expression in ira2Δ/Δ biofilms reversed the effect. In conclusion, we provide evidence that the AHP1 gene critically determines the amphotericin B tolerance of C. albicans biofilms possibly by maintaining the persisters' antioxidant capacity. This finding will open up new avenues for developing therapies targeting the persister population of C. albicans biofilms. The mass spectrometry proteomics data are available via ProteomeXchange with identifier PXD004274. PMID:27644984
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Truong, Thuyen; Zeng, Guisheng; Qingsong, Lin; Kwang, Lim Teck; Tong, Cao; Chan, Fong Yee; Wang, Yue; Seneviratne, Chaminda Jayampath
2016-11-01
Candida albicans is a major fungal pathogen causing lethal infections in immunocompromised patients. C. albicans forms antifungal tolerant biofilms contributing significantly to therapeutic failure. The recently established haploid C. albicans biofilm model provides a new toolbox to uncover the mechanism governing the higher antifungal tolerance of biofilms. Here, we comprehensively examined the proteomics and antifungal susceptibility of standard diploid (SC5314 and BWP17) and stable haploid (GZY792 and GZY803) strains of C. albicans biofilms. Subsequent downstream analyses identified alkyl hydroperoxide reductase 1 (AHP1) as a critical determinant of C. albicans biofilm's tolerance of amphotericin B. At 32 μg/ml of amphotericin B, GZY803 haploid biofilms showed 0.1% of persister population as compared with 1% of the diploid biofilms. AHP1 expression was found to be lower in GZY803 biofilms, and AHP1 overexpression in GZY803 restored the percentage of persister population. Consistently, deleting AHP1 in the diploid strain BWP17 caused a similar increase in amphotericin B susceptibility. AHP1 expression was also positively correlated with the antioxidant potential. Furthermore, C. albicans ira2Δ/Δ biofilms were susceptible to amphotericin B and had a diminished antioxidant capacity. Interestingly, AHP1 overexpression in the ira2Δ/Δ strain restored the antioxidant potential and enhanced the persister population against amphotericin B, and shutting down the AHP1 expression in ira2Δ/Δ biofilms reversed the effect. In conclusion, we provide evidence that the AHP1 gene critically determines the amphotericin B tolerance of C. albicans biofilms possibly by maintaining the persisters' antioxidant capacity. This finding will open up new avenues for developing therapies targeting the persister population of C. albicans biofilms. The mass spectrometry proteomics data are available via ProteomeXchange with identifier PXD004274. © 2016 by The American Society for
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Hydroxychavicol: A phytochemical targeting cutaneous fungal infections
Ali, Intzar; Satti, Naresh Kumar; Dutt, Prabhu; Prasad, Rajendra; Khan, Inshad Ali
2016-01-01
The present study was designed to investigate the potency of hydroxychavicol on selected cutaneous human pathogenic fungi by the use of in vitro and in vivo assays and mechanistic characterization along with toxicological effects. Hydroxychavicol consistently displayed a fungicidal effect against all fungal species tested. Inoculum concentrations over the range of 104 to 107 CFU/ml did not significantly alter its antifungal potential and time–kill curve results revealed concentration–dependent killing. It also inhibited the growth of biofilm generated by Trichophyton mentagrophytes and Candida parapsilosis and reduced the preformed biofilms. Hydroxychavicol was highly effective in the treatment, and mycological eradication of an experimentally induced topical infection model of dermatophytosis (tinea corporis) and cutaneous candidiasis in guinea pigs, respectively. The mode of action of hydroxychavicol appears to originate from the disruption of cell membrane integrity. Administration of hydroxychavicol in mice at 500 mg per kg of body weight by orally produced no overt toxicity. The retention capacity of hydroxychavicol in vitro, in the presence of keratin has attributed to its in vivo effectiveness in the guinea pig model of topical infections. Furthermore, it is suggestive of its potential use as phytochemical for topical use in cutaneous fungal infections. PMID:27897199
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Inhibitory activity of isoniazid and ethionamide against Cryptococcus biofilms.
Cordeiro, Rossana de Aguiar; Serpa, Rosana; Marques, Francisca Jakelyne de Farias; de Melo, Charlline Vládia Silva; Evangelista, Antonio José de Jesus; Mota, Valquíria Ferreira; Brilhante, Raimunda Sâmia Nogueira; Bandeira, Tereza de Jesus Pinheiro Gomes; Rocha, Marcos Fábio Gadelha; Sidrim, José Júlio Costa
2015-11-01
In recent years, the search for drugs to treat systemic and opportunistic mycoses has attracted great interest from the scientific community. This study evaluated the in vitro inhibitory effect of the antituberculosis drugs isoniazid and ethionamide alone and combined with itraconazole and fluconazole against biofilms of Cryptococcus neoformans and Cryptococcus gattii. Antimicrobials were tested at defined concentrations after susceptibility assays with Cryptococcus planktonic cells. In addition, we investigated the synergistic interaction of antituberculosis drugs and azole derivatives against Cryptococcus planktonic cells, as well as the influence of isoniazid and ethionamide on ergosterol content and cell membrane permeability. Isoniazid and ethionamide inhibited both biofilm formation and viability of mature biofilms. Combinations formed by antituberculosis drugs and azoles proved synergic against both planktonic and sessile cells, showing an ability to reduce Cryptococcus biofilms by approximately 50%. Furthermore, isoniazid and ethionamide reduced the content of ergosterol in Cryptococcus spp. planktonic cells and destabilized or permeabilized the fungal cell membrane, leading to leakage of macromolecules. Owing to the paucity of drugs able to inhibit Cryptococcus biofilms, we believe that the results presented here might be of interest in the designing of new antifungal compounds.
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Staphylococcus aureus biofilms: Nemesis of endoscopic sinus surgery.
Singhal, Deepti; Foreman, Andrew; Jervis-Bardy, Joshua; Bardy, Josh-Jervis; Wormald, Peter-John
2011-07-01
Chronic rhinosinusitis (CRS) patients with biofilms have persistent postoperative symptoms, ongoing mucosal inflammation, and recurrent infections. Recent evidence suggests that biofilms of differing species confer varying disease profiles in CRS patients. We aimed to prospectively investigate the effects of Staphylococcus aureus, Pseudomonas aeruginosa, Haemophilus influenzae, and fungal biofilms on outcomes following endoscopic sinus surgery (ESS). Prospective blinded study. In this prospective blinded study, 39 patients undergoing ESS for CRS assessed their symptoms preoperatively using internationally accepted standardized symptom scoring systems and quality-of-life measures (10-point visual analog scale, Sino-Nasal Outcome Test-20, global severity of CRS). Their sinonasal mucosa was graded (Lund-Kennedy scale) and extent of radiologic disease on computed tomography scans scored (Lund-McKay scale). Random sinonasal tissue samples were assessed for different bacterial species forming biofilms by using fluorescent in-situ hybridization and confocal laser microscopy. For 12 months after surgery, CRS symptoms, quality of life, and objective evidence of persisting disease were assessed by using the preoperative tools. Different bacterial species combinations were found in 30 of 39 patients; 60% of these 30 biofilms were polymicrobial biofilms and 70% had S aureus biofilms. Preoperative nasendoscopy and radiologic disease severity were significantly worse in patients with multiple biofilms (P = .02 and P = .01, respectively), and they had worse postsurgery mucosal outcomes on endoscopy (P = .01) requiring significantly more postoperative visits (P = .04). Those with S aureus biofilms progressed poorly with their symptom scores and quality-of-life outcomes, with significant differences in nasendoscopy scores (P = .007). S. aureus biofilms play a dominant role in negatively affecting outcomes of ESS with persisting postoperative symptoms, ongoing mucosal inflammation
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Biosynthesized silver nanoparticles to control fungal infections in indoor environments
NASA Astrophysics Data System (ADS)
Deyá, Cecilia; Bellotti, Natalia
2017-06-01
Fungi grow especially in dark and moist areas, deteriorating the indoor environment and causing infections that particularly affect immunosuppressed individuals. Antimicrobial coatings have as principal objective to prevent biofilm formation and infections by incorporation of bioactive additives. In this sense, metallic nanoparticles, such as silver, have proven to be active against different microorganisms specially bacteria. Biosynthesized method is a promising environmentally friendly option to obtain nanoparticles. The aim of this research was assess the employment of plants extracts of Aloysia triphylla (cedrón), Laurelia sempervirens (laurel) and Ruta chalepensis (ruda) to obtain silver nanoparticles to be used as an antimicrobial additive to a waterborne coating formulation. The products obtained were assessed against fungal isolates from biodeteriorated indoor coatings. The fungi were identified by conventional and molecular techniques as Chaetomium globosum and Alternaria alternate. The results revealed that the coating with silver nanoparticles obtained with L. sempervirens extract at 60 °C with a size of 9.8 nm was the most efficient against fungal biofilm development.
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Costa Silva, Rose Anny; da Silva, Cecília Rocha; de Andrade Neto, João Batista; da Silva, Anderson Ramos; Campos, Rosana Sousa; Sampaio, Letícia Serpa; do Nascimento, Francisca Bruna Stefany Aires; da Silva Gaspar, Brenda; da Cruz Fonseca, Said Gonçalves; Josino, Maria Aparecida Alexandre; Grangeiro, Thalles Barbosa; Gaspar, Danielle Macedo; de Lucena, David Freitas; de Moraes, Manoel Odorico; Cavalcanti, Bruno Coêlho; Nobre Júnior, Hélio Vitoriano
2017-06-01
Recent research has shown broad antifungal activity of the classic antidepressants selective serotonin reuptake inhibitors (SSRIs). This fact, combined with the increased cross-resistance frequency of the genre Candida regarding the main treatment today, fluconazole, requires the development of novel therapeutic strategies. In that context, this study aimed to assess the antifungal potential of fluoxetine, sertraline, and paroxetine against fluconazole-resistant Candida spp. planktonic cells, as well as to assess the mechanism of action and the viability of biofilms treated with fluoxetine. After 24 h, the fluconazole-resistant Candida spp. strains showed minimum inhibitory concentration (MIC) in the ranges of 20-160 μg/mL for fluoxetine, 10-20 μg/mL for sertraline, and 10-100.8 μg/mL for paroxetine by the broth microdilution method (M27-A3). According to our data by flow cytometry, each of the SSRIs cause fungal death after damaging the plasma and mitochondrial membrane, which activates apoptotic signaling pathways and leads to dose-dependant cell viability loss. Regarding biofilm-forming isolates, the fluoxetine reduce mature biofilm of all the species tested. Therefore, it is concluded that SSRIs are capable of inhibit the growth in vitro of Candida spp., both in planktonic form, as biofilm, inducing cellular death by apoptosis. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Analysis of black fungal biofilms occurring at domestic water taps. II: potential routes of entry.
Heinrichs, Guido; Hübner, Iris; Schmidt, Carsten K; de Hoog, G Sybren; Haase, Gerhard
2013-06-01
Formation of tenacious and massive black biofilms was occasionally observed at the water-air interphase of water taps and in associated habitats at several locations in Germany. Exophiala lecanii-corni was proven to be the dominant component of these biofilms. Water utility companies were interested to understand by which route fungi building these black biofilms enter their habitat at affected sites in domestic sanitary. A wide variety of fungi is known to be common in wet indoor environments, as well as in the drinking water resources. Two possible routes of entry are therefore considered as follows: (a) distribution by the drinking water system or (b) a retrograde route of colonisation. Previous compositional analysis revealed that the black constituents of biofilms primarily belong to the herpotrichiellaceous black yeast and relatives. Therefore, a systematic search for black fungi in the drinking water system was performed using Sabouraud's glucose agar medium with chloramphenicol and erythritol-chloramphenicol agar as isolation media. Cadophora malorum was the dominant fungus in the investigated drinking water systems, and samples taken from the house connections (n = 50; 74 %, <200 cfu/L), followed by a so far undescribed Alternaria sp. (28 %; <10 cfu/L) and E. castellanii (26 %; <10 cfu/L). Of note, C. malorum was not present in any previously analysed biofilm. Since E. lecanii-corni was not found in any water sample from the distribution system tested, but represented the most abundant species in dark biofilms previously analysed, a retrograde route of contamination in case of E. lecanii-corni can be assumed.
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Bojsen, Rasmus; Regenberg, Birgitte; Gresham, David; Folkesson, Anders
2016-02-23
Fungal infections are an increasing clinical problem. Decreased treatment effectiveness is associated with biofilm formation and drug recalcitrance is thought to be biofilm specific. However, no systematic investigations have tested whether resistance mechanisms are shared between biofilm and planktonic populations. We performed multiplexed barcode sequencing (Bar-seq) screening of a pooled collection of gene-deletion mutants cultivated as biofilm and planktonic cells. Screening for resistance to the ergosterol-targeting fungicide amphotericin B (AmB) revealed that the two growth modes had significant overlap in AmB-persistent mutants. Mutants defective in sterol metabolism, ribosome biosynthesis, and the TORC1 and Ras pathways showed increased persistence when treated with AmB. The ras1, ras2 and tor1 mutants had a high-persister phenotype similar to wild-type biofilm and planktonic cells exposed to the TORC1 pathway inhibitor rapamycin. Inhibition of TORC1 with rapamycin also increased the proportion of persisters in Candida albicans and Candida glabrata. We propose that decreased TORC1-mediated induction of ribosome biosynthesis via Ras can lead to formation of AmB-persister cells regardless of whether the cells are in planktonic or biofilm growth mode. Identification of common pathways leading to growth mode-independent persister formation is important for developing novel strategies for treating fungal infections.
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Microplastics alter composition of fungal communities in aquatic ecosystems.
Kettner, Marie Therese; Rojas-Jimenez, Keilor; Oberbeckmann, Sonja; Labrenz, Matthias; Grossart, Hans-Peter
2017-11-01
Despite increasing concerns about microplastic (MP) pollution in aquatic ecosystems, there is insufficient knowledge on how MP affect fungal communities. In this study, we explored the diversity and community composition of fungi attached to polyethylene (PE) and polystyrene (PS) particles incubated in different aquatic systems in north-east Germany: the Baltic Sea, the River Warnow and a wastewater treatment plant. Based on next generation 18S rRNA gene sequencing, 347 different operational taxonomic units assigned to 81 fungal taxa were identified on PE and PS. The MP-associated communities were distinct from fungal communities in the surrounding water and on the natural substrate wood. They also differed significantly among sampling locations, pointing towards a substrate and location specific fungal colonization. Members of Chytridiomycota, Cryptomycota and Ascomycota dominated the fungal assemblages, suggesting that both parasitic and saprophytic fungi thrive in MP biofilms. Thus, considering the worldwide increasing accumulation of plastic particles as well as the substantial vector potential of MP, especially these fungal taxa might benefit from MP pollution in the aquatic environment with yet unknown impacts on their worldwide distribution, as well as biodiversity and food web dynamics at large. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.
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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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Fungal Ferromanganese Mineralisation in Cretaceous Dinosaur Bones from the Gobi Desert, Mongolia
Wrzosek, Beata; Królikowska, Agata
2016-01-01
Well-preserved mycelia of fungal- or saprolegnia-like biota mineralised by ferromanganese oxides were found for the first time in long bones of Late Cretaceous dinosaurs from the Gobi Desert (Nemegt Valley, Mongolia). The mycelia formed a biofilm on the wall of the bone marrow cavity and penetrated the osteon channels of the nearby bone tissue. Optical microscopy, Raman, SEM/EDS, SEM/BSE, electron microprobe and cathodoluminescence analyses revealed that the mineralisation of the mycelia proceeded in two stages. The first stage was early post-mortem mineralisation of the hyphae by Fe/Mn-oxide coatings and microconcretions. Probably this proceeded in a mildly acidic to circumneutral environment, predominantly due to heterotrophic bacteria degrading the mycelial necromass and liberating Fe and Mn sorbed by the mycelia during its lifetime. The second stage of mineralisation, which proceeded much later following the final burial of the bones in an alkaline environment, resulted from the massive precipitation of calcite and occasionally barite on the iron/manganese-oxide-coated mycelia. The mineral phases produced by fungal biofilms colonising the interiors of decaying dinosaur bones not only enhance the preservation (fossilisation) of fungal remains but can also be used as indicators of the geochemistry of the dinosaur burial sites. PMID:26863014
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Fungal Ferromanganese Mineralisation in Cretaceous Dinosaur Bones from the Gobi Desert, Mongolia.
Owocki, Krzysztof; Kremer, Barbara; Wrzosek, Beata; Królikowska, Agata; Kaźmierczak, Józef
2016-01-01
Well-preserved mycelia of fungal- or saprolegnia-like biota mineralised by ferromanganese oxides were found for the first time in long bones of Late Cretaceous dinosaurs from the Gobi Desert (Nemegt Valley, Mongolia). The mycelia formed a biofilm on the wall of the bone marrow cavity and penetrated the osteon channels of the nearby bone tissue. Optical microscopy, Raman, SEM/EDS, SEM/BSE, electron microprobe and cathodoluminescence analyses revealed that the mineralisation of the mycelia proceeded in two stages. The first stage was early post-mortem mineralisation of the hyphae by Fe/Mn-oxide coatings and microconcretions. Probably this proceeded in a mildly acidic to circumneutral environment, predominantly due to heterotrophic bacteria degrading the mycelial necromass and liberating Fe and Mn sorbed by the mycelia during its lifetime. The second stage of mineralisation, which proceeded much later following the final burial of the bones in an alkaline environment, resulted from the massive precipitation of calcite and occasionally barite on the iron/manganese-oxide-coated mycelia. The mineral phases produced by fungal biofilms colonising the interiors of decaying dinosaur bones not only enhance the preservation (fossilisation) of fungal remains but can also be used as indicators of the geochemistry of the dinosaur burial sites.
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Effect of fluoride and chlorhexidine digluconate mouthrinses on plaque biofilms.
Rabe, Per; Twetman, Svante; Kinnby, Bertil; Svensäter, Gunnel; Davies, Julia R
2015-01-01
To develop a model in which to investigate the architecture of plaque biofilms formed on enamel surfaces in vivo and to compare the effects of anti-microbial agents of relevance for caries on biofilm vitality. Materials and Methodology : Enamel discs mounted on healing abutments in the pre-molar region were worn by three subjects for 7 days. Control discs were removed before subjects rinsed with 0.1% chlorhexidine digluconate (CHX) or 0.2% sodium fluoride (NaF) for 1 minute. Biofilms were stained with Baclight Live/Dead and z-stacks of images created using confocal scanning laser micoscopy. The levels of vital and dead/damaged bacteria in the biofilms, assessed as the proportion of green and red pixels respectively, were analysed using ImageTrak(®) software. Results : The subjects showed individual differences in biofilm architecture. The thickness of the biofilms varied from 28-96µm although cell density was always the greatest in the middle layers. In control biofilms, the overall levels of vitality were high (71-98%) especially in the area closest to the enamel interface. Rinsing with either CHX or NaF caused a similar reduction in overall vitality. CHX exerted an effect throughout the biofilm, particularly on the surface of cell clusters whereas NaF caused cell damage/death mainly in the middle to lower biofilm layers. Conclusion : We describe a model that allows the formation of mature, undisturbed oral biofilms on human enamel surfaces in vivo and show that CHX and NaF have a similar effect on overall vitality but differ in their sites of action.
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Liu, Xinning; Wang, Decai; Yu, Cuixiang; Li, Tao; Liu, Jianqiao; Sun, Shujuan
2016-01-01
Candida is an important opportunistic fungal pathogen, especially in biofilm associated infections. The formation of a Candida biofilm can decrease Candida sensitivity to antifungal drugs and cause drug resistance. Although many effective antifungal drugs are available, their applications are limited due to their high toxicity and cost. Seeking new antifungal agents that are effective against biofilm-associated infection is an urgent need. Many research efforts are underway, and some progress has been made in this field. It has been shown that the arachidonic acid cascade plays an important role in fungal morphogenesis and pathogenicity. Notably, prostaglandin E2 (PGE2) can promote the formation of a Candida biofilm. Recently, the inhibition of PGE2 has received much attention. Studies have shown that cyclooxygenase (COX) inhibitors, such as aspirin, ibuprofen, and indomethacin, combined with fluconazole can significantly reduce Candida adhesion and biofilm development and increase fluconazole susceptibility; the MIC of fluconazole can be decrease from 64 to 2 μg/ml when used in combination with ibuprofen. In addition, in vivo studies have also confirmed the antifungal activities of these inhibitors. In this article, we mainly review the relationship between PGE2 and Candida biofilm, summarize the antifungal activities of COX inhibitors and analyze the possible antifungal activity of microsomal prostaglandin E synthase-1 (MPGES-1) inhibitors; additionally, other factors that influence PGE2 production are also discussed. Hopefully this review can disclose potential antifungal targets based on the arachidonic acid cascade and provide a prevailing strategy to alleviate Candida albicans biofilm formation. PMID:27999568
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Common fungal diseases of Russian forests
Evgeny P. Kuz' michevl; Ella s. Sokolova; Elena G. Kulikova
2001-01-01
Describes common fungal diseases of Russian forests, including diagnostic signs and symptoms, pathogen biology, damage caused by the disease, and methods of control. The fungal diseases are divided into two groups: those that are the most common in Russian forests and those that are found only in Russia. Within each group, diseases are subdivided by plant organ...
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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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Trofa, David; Agovino, Mariangela; Stehr, Frank; Schäfer, Wilhelm; Rykunov, Dmitry; Fiser, András; Hamari, Zsuzsanna; Nosanchuk, Joshua D.; Gácser, Attila
2009-01-01
A reconstituted human tissue model was used to mimic Candida albicans and Candida parapsilosis infection in order to investigate the protective effects of acetylsalicylic acid (aspirin, ASA). We found that therapeutic concentrations of ASA reduced tissue damage in the in vitro infection model. We further evaluated the lipase inhibitory effects of ASA by investigating the growth of C. albicans, C. parapsilosis and C. parapsilosis lipase negative (Δcplip1-2/Δcplip1-2) mutants in a lipid rich minimal medium supplemented with olive oil and found that a therapeutic concentration of ASA inhibited the growth of wild type fungi. The lipase inhibitors quinine and ebelactone B were also shown to reduce growth and protect against tissue damage from Candida species, respectively. A lipolytic activity assay also showed that therapeutic concentrations of ASA inhibited C. antarctica and C. cylindracea purified lipases obtained through a commercial kit. The relationship between ASA and lipase was characterized through a computed structural model of the Lipase-2 protein from C. parapsilosis in complex with ASA. The results suggest that development of inhibitors of fungal lipases could result in broad-spectrum therapeutics, especially since fungal lipases are not homologous to their human analogues. PMID:19703582
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Masaphy, Segula; Lavi, Ido; Sultz, Stephan; Zabari, Limor
2014-06-01
Fungi can grow in extreme habitats, such as natural stone and mineral building materials, sometimes causing deterioration. Efflorescence-concentrated salt deposits-results from water movement through building material; it can damage masonry materials and other bricks. Fungal isolate KUR1, capable of growth on, and dissolution of stone chips composing terrazzo-type floor tiles, was isolated from such tiles showing fiber-like crystalline efflorescence. The isolate's ribosomal DNA sequences were 100 % identical to those of Nigrospora sphaerica. The ability of KUR1 to colonize and degrade the different stone chips composing the tiles was studied in axenic culture experiments. When exposed to each of the different mineral chip types composed of dolomite, calcite, or calcite-apatite mineral in low-nutrition medium, the fungus showed selective nutrient consumption, and different growth and stone mineral dissolution rates. Micromorphological examination of the fungus-colonized chips by electron microscopy showed the production of a fungal biofilm with thin films around the hyphae on the surface of the examined chips and disintegration of the calcite-apatite fraction. More than 70 % dissolution of the introduced powdered (<1 mm particle size) mineral was obtained within 10 days of incubation for the soft calcite-apatite fraction.
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Mello, Thaís P; Aor, Ana Carolina; Gonçalves, Diego S; Seabra, Sergio H; Branquinha, Marta H; Santos, André L S
2016-08-01
Reported herein is the ability of Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans conidia to adhere, differentiate into hyphae and form biofilms on both polystyrene and lung epithelial cells. To different degrees, all of the fungi adhered to polystyrene after 4 h, with a predominance of those with germinated conidia. Prolonged fungi-polystyrene contact resulted in the formation of a monolayer of intertwined mycelia, which was identified as a typical biofilm structure due to the presence of a viable mycelial biomass, extracellular matrix and enhanced antifungal resistance. Ultrastructural details were revealed by SEM and CLSM, showing the dense compaction of the mycelial biomass and the presence of channels within the organized biofilm. A similar biofilm structure was observed following the co-culture of each fungus with A549 cells, revealing a mycelial trap covering all of the lung epithelial monolayer. Collectively, these results highlight the potential for biofilm formation by these clinically relevant fungal pathogens.
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The protective role of immunoglobulins in fungal infections and inflammation.
Elluru, Sri Ramulu; Kaveri, Srini V; Bayry, Jagadeesh
2015-03-01
Increased incidence of fungal infections in the immunocompromised individuals and fungi-mediated allergy and inflammatory conditions in immunocompetent individuals is a cause of concern. Consequently, there is a need for efficient therapeutic alternatives to treat fungal infections and inflammation. Several studies have demonstrated that antibodies or immunoglobulins have a role in restricting the fungal burden and their clearance. However, based on the data from monoclonal antibodies, it is now evident that the efficacy of antibodies in fungal infections is dependent on epitope specificity, abundance of protective antibodies, and their isotype. Antibodies confer protection against fungal infections by multiple mechanisms that include direct neutralization of fungi and their antigens, inhibition of growth of fungi, modification of gene expression, signaling and lipid metabolism, causing iron starvation, inhibition of polysaccharide release, and biofilm formation. Antibodies promote opsonization of fungi and their phagocytosis, complement activation, and antibody-dependent cell toxicity. Passive administration of specific protective monoclonal antibodies could also prove to be beneficial in drug resistance cases, to reduce the dosage and associated toxic symptoms of anti-fungal drugs. The longer half-life of the antibodies and flexibilities to modify their structure/forms are additional advantages. The clinical data obtained with two monoclonal antibodies should incite interests in translating pre-clinical success into the clinics. The anti-inflammatory and immunoregulatory role of antibodies in fungal inflammation could be exploited by intravenous immunoglobulin or IVIg.
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Susceptibility of Candida glabrata biofilms to echinocandins: alterations in the matrix composition.
Rodrigues, Célia F; Rodrigues, Maria Elisa; Henriques, Mariana
2018-05-25
Candidiases are the most recurrent fungal infections, especially among immunosuppressed patients. Although Candida albicans is still the most widespread isolated species, non-Candida albicans Candida species have been increasing. The goal of this work was to determine the susceptibility of C. glabrata biofilms to echinocandins and to evaluate their effect on the biofilm matrix composition, comparing the results with other Candida species. Drug susceptibilities were assessed through the determination of minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC) and minimum biofilm eradication concentration (MBEC) of caspofungin (Csf) and micafugin (Mcf). The β-1,3 glucans content of the matrices was assessed after contact with the drugs. The data suggest that, generally, after contact with echinocandins, the concentration of β-1,3 glucans increased. These adjustments in the matrix composition of C. glabrata biofilms and the chemical differences between Csf and Mcf, seem responsible and may determine the effectivity of the drug responses.
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De Cremer, Kaat; Lanckacker, Ellen; Cools, Tanne L; Bax, Marijke; De Brucker, Katrijn; Cos, Paul; Cammue, Bruno P A; Thevissen, Karin
2015-01-01
Mucosal biofilm-related fungal infections are very common, and the incidence of recurrent oral and vulvovaginal candidiasis is significant. As resistance to azoles (the preferred treatment) is occurring, we aimed at identifying compounds that increase the activity of miconazole against Candida albicans biofilms. We screened 1,600 compounds of a drug-repositioning library in combination with a subinhibitory concentration of miconazole. Synergy between the best identified potentiators and miconazole was characterized by checkerboard analyses and fractional inhibitory concentration indices. Hexachlorophene, pyrvinium pamoate, and artesunate act synergistically with miconazole in affecting C. albicans biofilms. Synergy was most pronounced for artesunate and structural homologues thereof. No synergistic effect could be observed between artesunate and fluconazole, caspofungin, or amphotericin B. Our data reveal enhancement of the antibiofilm activity of miconazole by artesunate, pointing to potential combination therapy consisting of miconazole and artesunate to treat C. albicans biofilm-related infections. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
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Effects of short-chain fatty acids on Actinomyces naeslundii biofilm formation.
Yoneda, S; Kawarai, T; Narisawa, N; Tuna, E B; Sato, N; Tsugane, T; Saeki, Y; Ochiai, K; Senpuku, H
2013-10-01
Actinomyces naeslundii is an early colonizer and has important roles in the development of the oral biofilm. Short-chain fatty acids (SCFA) are secreted extracellularly as a product of metabolism by gram-negative anaerobes, e.g. Porphyromonas gingivalis and Fusobacterium nucleatum; and the SCFA may affect biofilm development with interaction between A. naeslundii and gram-negative bacteria. Our aim was to investigate the effects of SCFA on biofilm formation by A. naeslundii and to determine the mechanism. We used the biofilm formation assay in 96-well microtiter plates in tryptic soy broth without dextrose and with 0.25% sucrose using safranin stain of the biofilm monitoring 492 nm absorbance. To determine the mechanism by SCFA, the production of chaperones and stress-response proteins (GrpE and GroEL) in biofilm formation was examined using Western blot fluorescence activity with GrpE and GroEL antibodies. Adding butyric acid (6.25 mm) 0, 6 and 10 h after beginning culture significantly increased biofilm formation by A. naeslundii, and upregulation was observed at 16 h. Upregulation was also observed using appropriate concentrations of other SCFA. In the upregulated biofilm, production of GrpE and GroEL was higher where membrane-damaged or dead cells were also observed. The upregulated biofilm was significantly reduced by addition of anti-GroEL antibody. The data suggest biofilm formation by A. naeslundii was upregulated dependent on the production of stress proteins, and addition of SCFA increased membrane-damaged or dead cells. Production of GroEL may physically play an important role in biofilm development. 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
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Large-scale production and isolation of Candida biofilm extracellular matrix.
Zarnowski, Robert; Sanchez, Hiram; Andes, David R
2016-12-01
The extracellular matrix of biofilm is unique to the biofilm lifestyle, and it has key roles in community survival. A complete understanding of the biochemical nature of the matrix is integral to the understanding of the roles of matrix components. This knowledge is a first step toward the development of novel therapeutics and diagnostics to address persistent biofilm infections. Many of the assay methods needed for refined matrix composition analysis require milligram amounts of material that is separated from the cellular components of these complex communities. The protocol described here explains the large-scale production and isolation of the Candida biofilm extracellular matrix. To our knowledge, the proposed procedure is the only currently available approach in the field that yields milligram amounts of biofilm matrix. This procedure first requires biofilms to be seeded in large-surface-area roller bottles, followed by cell adhesion and biofilm maturation during continuous movement of the medium across the surface of the rotating bottle. The formed matrix is then separated from the entire biomass using sonication, which efficiently removes the matrix without perturbing the fungal cell wall. Subsequent filtration, dialysis and lyophilization steps result in a purified matrix product sufficient for biochemical, structural and functional assays. The overall protocol takes ∼11 d to complete. This protocol has been used for Candida species, but, using the troubleshooting guide provided, it could be adapted for other fungi or bacteria.
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Simvastatin inhibits planktonic cells and biofilms of Candida and Cryptococcus species.
Brilhante, Raimunda Sâmia Nogueira; Caetano, Erica Pacheco de; Oliveira, Jonathas Sales; Castelo-Branco, Débora de Souza Collares Maia; Souza, Elizabeth Ribeiro Yokobatake; Alencar, Lucas Pereira de; Cordeiro, Rossana de Aguiar; Bandeira, Tereza de Jesus Pinheiro Gomes; Sidrim, José Júlio Costa; Rocha, Marcos Fábio Gadelha
2015-01-01
The antifungal activity of some statins against different fungal species has been reported. Thus, at the first moment, the in vitro antifungal activity of simvastatin, atorvastatin and pravastatin was tested against Candida spp. and Cryptococcus spp. Then, in a second approach, considering that the best results were obtained for simvastatin, this drug was evaluated in combination with antifungal drugs against planktonic growth and tested against biofilms of Candida spp. and Cryptococcus spp. Drug susceptibility testing was performed using the microdilution broth method, as described by the Clinical and Laboratory Standards Institute. The interaction between simvastatin and antifungals against planktonic cells was analyzed by calculating the fractional inhibitory concentration index. Regarding biofilm susceptibility, simvastatin was tested against growing biofilm and mature biofilm of one strain of each tested yeast species. Simvastatin showed inhibitory effect against Candida spp. and Cryptococcus spp. with minimum inhibitory concentration values ranging from 15.6 to 1000 mg L(-1) and from 62.5 to 1000 mg L(-1), respectively. The combination of simvastatin with itraconazole and fluconazole showed synergism against Candida spp. and Cryptococcus spp., while the combination of simvastatin with amphotericin B was synergistic only against Cryptococcus spp. Concerning the biofilm assays, simvastatin was able to inhibit both growing biofilm and mature biofilm of Candida spp. and Cryptococcus spp. The present study showed that simvastatin inhibits planktonic cells and biofilms of Candida and Cryptococcus species. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.
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Ciok-Pater, Emilia; Gospodarek, Eugenia; Prazyńska, Małgorzata; Bogiel, Tomasz
2009-01-01
The increase of fungal infections in recent years is connected with the progress in medicine. The vast usage of biomaterials is an inseparable element of contemporary medicine but it also leads to development of infections. The ability to produce biofilm by those yeasts plays an important role in the pathogenesis of candidiasis. Candida biofilm can form on the surface of plastic materials (silicon, polychloride vinyl, polymethacrylate methyl) used to catheters, drains and dentures production that is why it is a serious problem in case of fungal infections in patients who during the diagnosis and treatment have contact with biomaterials. The aim of the study was the assessment of ability to form biofilm on the surface of different biomaterials (latex silicon, polychloride vinyl, polystyrene, nylon and polymethacrylate methyl). 150 strains of Candida sp. were examined: 85 (56.7%) C. albicans and 65 (43.3%) C. non-albicans. The examined yeasts produced biofilm on the surface of polymethacrylate methyl in 39.3%, latex silicone in 38.7%, polychloride vinyl in 38.0%, polystyrene in 35.3% and nylon in 30.7%. Biofilm was most frequently produced by the strains of C. albicans, C. tropicalis, C. glabrata, C. parapsilosis, C. krusei and C. lusitaniae species.
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Li, Lei; Yang, Min; Luo, Jun; Qu, Qing; Chen, Ying; Liang, Lianming; Zhang, Keqin
2016-11-01
In soil, nematode-trapping fungi and bacteria often share microhabitats and interact with each other, but effects of fungus-associated bacteria on its trap formation are underestimated. We have ascertained the presence of Stenotrophomonas and Rhizobium genera associated with A. oligospora GJ-1. After A. oligospora GJ-1 without associated bacteria (cured Arthrobotrys) was co-cultivated with Stenotrophomonas and its supernatant extract, microscopic study of hyphae from co-cultivation indicated that bacterial biofilm formation on hyphae was related to trap formation in fungi and Stenotrophomonas supernatant extract. Four diketopiperazines (DKPs) were purified from Stenotrophomonas supernatant extract that could not induce traps in the cured Arthrobotrys. When cured Arthrobotrys was cultured with Stenotrophomonas and one of DKPs, polar attachment, bacterial biofilms on hyphae and trap formation in fungi were observed. After cured Arthrobotrys with bacterial biofilms was consecutively transferred several times on nutrient poor medium, trap formation disappeared with the disappearance of bacterial biofilms on hyphae. DKPs could facilitate chemotaxis of Stenotrophomonas towards fungal extract which was suggested to contribute to bacterial biofilms on hyphae. Furthermore, when cured Arthrobotrys was cultured with Stenotrophomonas and DKPs in soil, trap formation in fungi and bacterial biofilms on hyphae were also observed, and the fungal activity against nematode was enhanced. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.
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Johnson, Chad J; Cabezas-Olcoz, Jonathan; Kernien, John F; Wang, Steven X; Beebe, David J; Huttenlocher, Anna; Ansari, Hamayail; Nett, Jeniel E
2016-09-01
Neutrophils release extracellular traps (NETs) in response to planktonic C. albicans. These complexes composed of DNA, histones, and proteins inhibit Candida growth and dissemination. Considering the resilience of Candida biofilms to host defenses, we examined the neutrophil response to C. albicans during biofilm growth. In contrast to planktonic C. albicans, biofilms triggered negligible release of NETs. Time lapse imaging confirmed the impairment in NET release and revealed neutrophils adhering to hyphae and migrating on the biofilm. NET inhibition depended on an intact extracellular biofilm matrix as physical or genetic disruption of this component resulted in NET release. Biofilm inhibition of NETosis could not be overcome by protein kinase C activation via phorbol myristate acetate (PMA) and was associated with suppression of neutrophil reactive oxygen species (ROS) production. The degree of impaired NET release correlated with resistance to neutrophil attack. The clinical relevance of the role for extracellular matrix in diminishing NET production was corroborated in vivo using a rat catheter model. The C. albicans pmr1Δ/Δ, defective in production of matrix mannan, appeared to elicit a greater abundance of NETs by scanning electron microscopy imaging, which correlated with a decreased fungal burden. Together, these findings show that C. albicans biofilms impair neutrophil response through an inhibitory pathway induced by the extracellular matrix.
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Kumar, D; Banerjee, T; Chakravarty, J; Singh, S K; Dwivedi, A; Tilak, R
2016-01-01
Diabetic foot ulcers are a serious cause of diagnostic and therapeutic concern. The following study was undertaken to determine the fungal causes of diabetic foot ulcers, with their phenotypic and genotypic characterisation. A total of 155 diabetic foot ulcers were studied for 1 year. Deep tissue specimen was collected from the wounds, and crushed samples were plated on Sabouraud dextrose agar with chloramphenicol (0.05 g). Identification was done by growth on cornmeal agar, germ tube formation and urease test. For molecular identification, conserved portion of the 18S rDNA region, the adjacent internal transcribed spacer 1 (ITS1) and a portion of the 28S rDNA region were amplified, using the ITS1 and ITS2 primers. Antifungal susceptibility against voriconazole, fluconazole and amphotericin B was determined by standard broth microdilution method. Biofilm formation was studied in three steps. First, on the surface of wells of microtiter plates followed by quantification of growth by fungal metabolism measurement. Finally, biofilms were analysed by scanning electron microscopy (SEM). Fungal aetiology was found in 75 patients (48.38%). All were identified as Candida species (100%). The prevalence of different species was Candida tropicalis (34.6%), Candida albicans (29.3%), Candida krusei (16.0%), Candida parapsilosis (10.6%), Candida glabrata (9.33%). All were susceptible to amphotericin B (100%). On microtiter plate, all the isolates were viable within 48 h showing biofilms. The metabolic activity of cells in the biofilm increased with cellular mass, especially in the first 24 h. On SEM, majority showed budding yeast form. Non-albicans Candida spp. with potential biofilm forming ability are emerging as a predominant cause of diabetic foot ulcers.
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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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De Zoysa, Gayan Heruka; Glossop, Hugh Douglas; Sarojini, Vijayalekshmi
2018-02-25
Novel antifungal agents are required against pathogenic fungi such as Candida albicans. We report the anticandidal activity of battacin lipopeptide antibiotics with previously unexplored antifungal activity. From amongst sixteen battacin lipopeptides tested against C. alibicans (SC5314) the 4-methyl hexanoyl conjugated trimeric lipopeptide 13 emerged as the lead candidate with a MIC of 6.25 μM and negligible haemolysis of mouse red blood cells. The potency of this lipopeptide was maintained under acidic conditions. Additionally, antifungal activity was further enhanced with amphotericin B at its non-haemolytic concentrations. Herein we have demonstrated for the first time that battacin lipopeptides prevent C. albicans biofilm colonisation as well as inhibit pre-formed biofilms of this fungal pathogen. XTT biofilm assays revealed that 13 prevented colonisation of C. albicans biofilms at its MIC (6.25 μM) and, at a higher concentration, eradicated 24 h (25 μM) and 48 h (62.5 μM) old preformed biofilms. In comparison, we found that amphotericin at much lower concentrations prevented biofilm colonisation (0.78 μM) and inhibited 24 h old preformed biofilms (6.25 μM), however was completely inactive against 48 h old preformed biofilms. Thus, lipopeptide 13 is more effective than amphotericin at eradicating more mature C. albicans biofilms. The membrane lytic mechanism of action of compound 13 was validated by a colorimetric assay using lipid vesicles mimicking fungal membranes in which compound 13 effected an immediate dark purple to red colour transition of suspended vesicles upon peptide interaction. In addition, TEM images of C. albicans cells exposed to 13 showed clearly disrupted cellular membranes. Interestingly, compound 13 increased the endogenous generation of reactive oxygen species (ROS) in a concentration dependent manner. In the presence of an antioxidant, ascorbic acid, ROS production was diminished yet antifungal activity
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Guennoc, Cora Miquel; Rose, Christophe; Labbé, Jessy; Deveau, Aurélie
2018-05-17
Ectomycorrhizal (ECM) fungi establish symbiosis with roots of most trees of boreal and temperate ecosystems and are major drivers of nutrient fluxes between trees and the soil. ECM fungi constantly interact with bacteria all along their life cycle and the extended networks of hyphae provide a habitat for complex bacterial communities. Despite the important effects these bacteria can have on the growth and activities of ECM fungi, little is known about the mechanisms by which these microorganisms interact. Here we investigated the ability of bacteria to form biofilm on the hyphae of the ECM fungus Laccaria bicolor. We showed that the ability to form biofilms on the hyphae of the ECM fungus is widely shared among soil bacteria. Conversely, some fungi, belonging to the Ascomycete class, did not allow for the formation of bacterial biofilms on their surfaces. The formation of biofilms was also modulated by the presence of tree roots and ectomycorrhizae, suggesting that biofilm formation does not occur randomly in soil but that it is regulated by several biotic factors. In addition, our study demonstrated that the formation of bacterial biofilm on fungal hyphae relies on the production of networks of filaments made of extracellular DNA.
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Robertson, Emma J.; Wolf, Julie M.
2012-01-01
The fungal pathogen Cryptococcus neoformans can grow as a biofilm on a range of synthetic and prosthetic materials. Cryptococcal biofilm formation can complicate the placement of shunts used to relieve increased intracranial pressure in cryptococcal meningitis and can serve as a nidus for chronic infection. Biofilms are generally advantageous to pathogens in vivo, as they can confer resistance to antimicrobial compounds, including fluconazole and voriconazole in the case of C. neoformans. EDTA can inhibit biofilm formation by several microbes and enhances the susceptibility of biofilms to antifungal drugs. In this study, we evaluated the effect of sublethal concentrations of EDTA on the growth of cryptococcal biofilms. EDTA inhibited biofilm growth by C. neoformans, and the inhibition could be reversed by the addition of magnesium or calcium, implying that the inhibitory effect was by divalent cation starvation. EDTA also reduced the amount of the capsular polysaccharide glucuronoxylomannan shed into the biofilm matrix and decreased vesicular secretion from the cell, thus providing a potential mechanism for the inhibitory effect of this cation-chelating compound. Our data imply that the growth of C. neoformans biofilms requires the presence of divalent metals in the growth medium and suggest that cations are required for the export of materials needed for biofilm formation, possibly including extracellular vesicles. PMID:22941091
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High-Throughput Nano-Biofilm Microarray for Antifungal Drug Discovery
2013-06-25
High-Throughput Nano-Biofilm Microarray for Antifungal Drug Discovery Anand Srinivasan,a, c Kai P. Leung,d Jose L. Lopez-Ribot,b, c Anand K...Ramasubramaniana, c Departments of Biomedical Engineeringa and Biologyb and South Texas Center for Emerging Infectious Diseases, c The University of Texas at San...of the opportunistic fungal pathogen Candida albicans on a microarray platform. The mi- croarray consists of 1,200 individual cultures of 30 nl of C
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Cabezas-Olcoz, Jonathan; Wang, Steven X.; Huttenlocher, Anna; Ansari, Hamayail; Nett, Jeniel E.
2016-01-01
Neutrophils release extracellular traps (NETs) in response to planktonic C. albicans. These complexes composed of DNA, histones, and proteins inhibit Candida growth and dissemination. Considering the resilience of Candida biofilms to host defenses, we examined the neutrophil response to C. albicans during biofilm growth. In contrast to planktonic C. albicans, biofilms triggered negligible release of NETs. Time lapse imaging confirmed the impairment in NET release and revealed neutrophils adhering to hyphae and migrating on the biofilm. NET inhibition depended on an intact extracellular biofilm matrix as physical or genetic disruption of this component resulted in NET release. Biofilm inhibition of NETosis could not be overcome by protein kinase C activation via phorbol myristate acetate (PMA) and was associated with suppression of neutrophil reactive oxygen species (ROS) production. The degree of impaired NET release correlated with resistance to neutrophil attack. The clinical relevance of the role for extracellular matrix in diminishing NET production was corroborated in vivo using a rat catheter model. The C. albicans pmr1Δ/Δ, defective in production of matrix mannan, appeared to elicit a greater abundance of NETs by scanning electron microscopy imaging, which correlated with a decreased fungal burden. Together, these findings show that C. albicans biofilms impair neutrophil response through an inhibitory pathway induced by the extracellular matrix. PMID:27622514
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Aspergillus fumigatus biofilms in the clinical setting.
Müller, Frank-Michael C; Seidler, Marc; Beauvais, Anne
2011-04-01
We discuss in this work the role of Aspergillus biofilms in the clinical setting by reviewing the most recent findings on this topic. Aspergillus fumigatus can produce in vitro an extracellular hydrophobic matrix with typical biofilm characteristics under all static conditions tested, i.e., agar media, polystyrene and bronchial epithelial cells. Under static conditions the mycelial growth is greater than in shaken, submerged conditions. The extracellular matrix (ECM) is composed of galactomannan, α-1,3-glucans, monosaccharides and polyols, melanin and proteins including major antigens and hydrophobins. Typical biofilm structures were observed in the aspergillomas from two patients and in a murine model of invasive pulmonary aspergillosis. The results indicate that α-1,3-glucans plays a predominant role in the agglutination of the hyphae together in aerial conditions, and that nutrient starvation was responsible for mycelial death in aspergilloma. Melanin was produced during the infection, suggesting that this pigment is necessary for lung tissue invasion. All antifungal drugs are significantly less effective when A. fumigatus is grown under biofilm vs. planktonic conditions. Chronic persistence of a unique genotype of A. fumigatus in the respiratory tract of CF-patients and the presence of an ECM in vivo may have some therapeutical application for aspergillosis. The most appropriate antifungal drug should not be selected only on the basis of its efficiency to kill in vitro grown fungal cells, but also on its ability to penetrate the ECM.
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In vivo Candida glabrata biofilm development on foreign bodies in a rat subcutaneous model.
Kucharíková, Soňa; Neirinck, Bram; Sharma, Nidhi; Vleugels, Jef; Lagrou, Katrien; Van Dijck, Patrick
2015-03-01
Biofilm studies have been mostly dedicated to the major human fungal pathogen Candida albicans, whereas much less is known about this virulence factor in Candida glabrata, certainly under in vivo conditions. This study provides a deeper understanding of the biofilm development of C. glabrata, its architecture and susceptibility profile to fluconazole and echinocandins. In vitro and in vivo C. glabrata biofilms were developed inside serum-coated triple-lumen catheters placed in 24-well polystyrene plates or implanted subcutaneously in the back of a rat, respectively. Scanning electron microscopy and confocal scanning laser microscopy were used to visualize the biofilm architecture. Quantitative real-time PCR was used to demonstrate the expression profile of EPA1, EPA3, EPA6 and AWP1-AWP7 during in vivo biofilm formation. Mature biofilms were observed within the first 48 h and the amount of biofilm reached its maximum by 6 days. Architecturally, mature C. glabrata biofilms consisted of a thick network of yeast cells embedded in an extracellular matrix. Moreover, in vivo biofilms were susceptible to echinocandin drugs, whereas fluconazole remained ineffective. Gene expression profiling revealed that EPA3, EPA6, AWP2, AWP3 and AWP5 were up-regulated in in vivo biofilms compared with in vitro biofilms. C. glabrata is a unique microorganism, which, despite the lack of transition to the hyphal form, formed thick biofilms inside foreign bodies in vivo. To our knowledge, this is the first study that has described in vivo C. glabrata biofilm development and its architectural changes in detail and provides an insight into the susceptibility profile, as well as the gene expression machinery, of biofilm-associated infections. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
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Understanding plasma biofilm interactions for controlling infection and virulence
NASA Astrophysics Data System (ADS)
Flynn, Padrig B.; Gilmore, Brendan F.
2018-07-01
Bacterial biofilms are surface adhered communities of bacteria encased within a protective extracellular polymeric matrix. These heterogeneous microbial communities are characterized by elevated tolerance to antimicrobial agents, host immune clearance mechanisms and physical disinfection approaches. Atmospheric pressure non-thermal plasmas have proven to be highly effective in the eradication of bacteria and fungi in both planktonic and biofilm modes of growth at low temperatures, making it a promising approach for surface decontamination of both biotic and abiotic surfaces alike. In addition, non-thermal plasmas as a putative non-antibiotic approach to controlling infectious microorganisms, holds significant promise as an antibiotic alternative infection control strategy, with demonstrated efficacy against antibiotic resistant microorganisms. This topical review introduces the reader to key concepts in biofilm tolerance mechanisms relevant to treatment and control of these surface adhered bacterial communities with cold plasmas. In addition, the ability of plasma-derived active species to interact with both biofilm extracellular matrix components and bacterial cellular targets will be discussed in order to elucidate the mechanisms of antimicrobial and antibiofilm action. By understanding these fundamental interactions, plasma sources may be precisely tailored for antimicrobial applications, specifically for biofilm control where bacterial and fungal physiology (and sensitivity to physical and chemical decontamination) is markedly different from that of their planktonic, or free swimming, counterparts. Recently, novel roles for reactive oxygen and nitrogen species in the activity of conventional antibiotics have been proposed. This extends the possibility that plasmas may enhance the activity of conventional antibiotics and biocides in controlling these highly tolerant microbial populations. Lessons from classical biofilm microbiology can be usefully translated and
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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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Thein, Z M; Smaranayake, Y H; Smaranayake, L P
2007-11-01
Despite the increasing recognition of the role played by mixed species biofilms in health and disease, the behavior and factors modulating these biofilms remain elusive. We therefore compared the effect of serum, two dietary sugars (sucrose and galactose) and a biocide, chlorhexidine digluconate, on a dual species biofilm (DSB) of Candida albicans and Escherichia coli and, their single species biofilm (SSB) counterparts. Both modes of biofilm growth on polystyrene plastic surfaces were quantified using a viable cell count method and visualized using confocal scanning laser microscopy (CSLM). Present data indicate that co-culture of C. albicans with varying initial concentrations of E. coli leads to a significant inhibition of yeast growth (r=-0.964; p<0.001). Parallel ultrastructural studies using CSLM and a Live/Dead stain confirmed that E. coli growth rendered blastospores and hyphal yeasts non-viable in DSB. SSB of C. albicans showed pronounced growth when its growth surface was pretreated with serum and by sugar supplements in the incubating medium (p<0.05). Intriguingly, C. albicans in DSB was more resistant to the antiseptic effect of chlorhexidine digluconate. Taken together, the current data elucidate some features of the colonization resistance offered by bacteria in mixed bacterial/fungal habitats and how such phenomena may contribute to the development of fungal superinfection during antimicrobial therapy.
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De Cremer, Kaat; Delattin, Nicolas; De Brucker, Katrijn; Peeters, Annelies; Kucharíková, Soña; Gerits, Evelien; Verstraeten, Natalie; Michiels, Jan; Van Dijck, Patrick; Thevissen, Karin
2014-01-01
We here report on the in vitro activity of toremifene to inhibit biofilm formation of different fungal and bacterial pathogens, including Candida albicans, Candida glabrata, Candida dubliniensis, Candida krusei, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. We validated the in vivo efficacy of orally administered toremifene against C. albicans and S. aureus biofilm formation in a rat subcutaneous catheter model. Combined, our results demonstrate the potential of toremifene as a broad-spectrum oral antibiofilm compound. PMID:25288093
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Diagnosis of biofilm infections in cystic fibrosis patients.
Høiby, Niels; Bjarnsholt, Thomas; Moser, Claus; Jensen, Peter Østrup; Kolpen, Mette; Qvist, Tavs; Aanaes, Kasper; Pressler, Tanja; Skov, Marianne; Ciofu, Oana
2017-04-01
Chronic Pseudomonas aeruginosa biofilm lung infection in cystic fibrosis patients is the best described biofilm infection in medicine. The initial focus can be the paranasal sinuses and then follows repeated colonization and infection of the lungs by aspiration. The matrix of the biofilms is dominated by alginate and the pathogenesis of tissue damage is immune complex-mediated chronic inflammation dominated by polymorphonuclear leukocytes and their products (DNA, oxygen radicals and proteases). The P. aeruginosa biofilm infection can be diagnosed by microscopy of lung tissue, sputum and mucus from the paranasal sinuses, where aggregates of the bacteria are found surrounded by the abundant alginate matrix. Specific PNA-FISH probes can be used to identify P. aeruginosa and other pathogens in situ in the biofilms. Growth of mucoid colonies from the locations mentioned above is also diagnostic for biofilm infection. Rise of specific anti-P. aeruginosa antibodies is likewise diagnostic, IgG in serum in case of lung infection, sIgA in saliva or nasal secretions in case of paranasal sinus infection. Similar approaches have been developed to diagnose chronic biofilm infections in cystic fibrosis caused by other pathogens e.g., Stenotrophomonas, Burkholderia multivorans, Achromobacter xylosoxidans and Mycobacterium abscessus complex. © 2017 APMIS. Published by John Wiley & Sons Ltd.
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Al Ashhab, Ashraf; Sweity, Amer; Bayramoglu, Bihter; Herzberg, Moshe; Gillor, Osnat
2017-05-01
Laboratory-scale reverse osmosis (RO) flat-sheet systems were used with two parallel flow cells, one treated with cleaning agents and a control (ie undisturbed). The cleaning efforts increased the affinity of extracellular polymeric substances (EPS) to the RO membrane and altered the biofilm surface structure. Analysis of the membrane biofilm community composition revealed the dominance of Proteobacteria. However, within the phylum Proteobacteria, γ-Proteobacteria dominated the cleaned membrane biofilm, while β-Proteobacteria dominated the control biofilm. The composition of the fungal phyla was also altered by cleaning, with enhancement of Ascomycota and suppression of Basidiomycota. The results suggest that repeated cleaning cycles select for microbial groups that strongly attach to the RO membrane surface by producing rigid and adhesive EPS that hampers membrane performance.
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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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Brambilla, Eugenio; Ionescu, Andrei C; Cazzaniga, Gloria; Ottobelli, Marco; Samaranayake, Lakshman P
2016-05-01
Dietary carbohydrates and polyols affect the microbial colonization of oral surfaces by modulating adhesion and biofilm formation. The aim of this study was to evaluate the influence of a select group of l-carbohydrates and polyols on either Streptococcus mutans or Candida albicans adhesion and biofilm formation in vitro. S. mutans or C. albicans suspensions were inoculated on polystyrene substrata in the presence of Tryptic soy broth containing 5% of the following compounds: d-glucose, d-mannose, l-glucose, l-mannose, d- and l-glucose (raceme), d- and l-mannose (raceme), l-glucose and l-mannose, sorbitol, mannitol, and xylitol. Microbial adhesion (2 h) and biofilm formation (24 h) were evaluated using MTT-test and Scanning Electron Microscopy (SEM). Xylitol and l-carbohydrates induced the lowest adhesion and biofilm formation in both the tested species, while sorbitol and mannitol did not promote C. albicans biofilm formation. Higher adhesion and biofilm formation was noted in both organisms in the presence of d-carbohydrates relative to their l-carbohydrate counterparts. These results elucidate, hitherto undescribed, interactions of the individually tested strains with l- and d-carbohydrates, and how they impact fungal and bacterial colonization. In translational terms, our data raise the possibility of using l-form of carbohydrates and xylitol for dietary control of oral plaque biofilms. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Motility of Pseudomonas aeruginosa contributes to SOS-inducible biofilm formation.
Chellappa, Shakinah T; Maredia, Reshma; Phipps, Kara; Haskins, William E; Weitao, Tao
2013-12-01
DNA-damaging antibiotics such as ciprofloxacin induce biofilm formation and the SOS response through autocleavage of SOS-repressor LexA in Pseudomonas aeruginosa. However, the biofilm-SOS connection remains poorly understood. It was investigated with 96-well and lipid biofilm assays. The effects of ciprofloxacin were examined on biofilm stimulation of the SOS mutant and wild-type strains. The stimulation observed in the wild-type in which SOS was induced was reduced in the mutant in which LexA was made non-cleavable (LexAN) and thus SOS non-inducible. Therefore, the stimulation appeared to involve SOS. The possible mechanisms of inducible biofilm formation were explored by subproteomic analysis of outer membrane fractions extracted from biofilms. The data predicted an inhibitory role of LexA in flagellum function. This premise was tested first by functional and morphological analyses of flagellum-based motility. The flagellum swimming motility decreased in the LexAN strain treated with ciprofloxacin. Second, the motility-biofilm assay was performed, which tested cell migration and biofilm formation. The results showed that wild-type biofilm increased significantly over the LexAN. These results suggest that LexA repression of motility, which is the initial event in biofilm development, contributes to repression of SOS-inducible biofilm formation. Copyright © 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
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Staphylococcus aureus induces hypoxia and cellular damage in porcine dermal explants
USDA-ARS?s Scientific Manuscript database
Methicillin-resistant Staphylococcus aureus (MRSA) can infect wounds and produce difficult-to- treat biofilms. To determine the extent that MRSA biofilms can deplete oxygen, change pH and damage host tissue, we developed a porcine dermal explant model on which we cultured GFP-labeled MRSA biofilms. ...
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Chavez-Dozal, Alba A.; Lown, Livia; Jahng, Maximillian; Walraven, Carla J.
2014-01-01
Candida albicans is the 3rd most common cause of catheter-associated urinary tract infections, with a strong propensity to form drug-resistant catheter-related biofilms. Due to the limited efficacy of available antifungals against biofilms, drug repurposing has been investigated in order to identify novel agents with activities against fungal biofilms. Finasteride is a 5-α-reductase inhibitor commonly used for the treatment of benign prostatic hyperplasia, with activity against human type II and III isoenzymes. We analyzed the Candida Genome Database and identified a C. albicans homolog of type III 5-α-reductase, Dfg10p, which shares 27% sequence identity and 41% similarity to the human type III 5-α-reductase. Thus, we investigated finasteride for activity against C. albicans urinary biofilms, alone and in combination with amphotericin B or fluconazole. Finasteride alone was highly effective in the prevention of C. albicans biofilm formation at doses of ≥16 mg/liter and the treatment of preformed biofilms at doses of ≥128 mg/liter. In biofilm checkerboard analyses, finasteride exhibited synergistic activity in the prevention of biofilm formation in a combination of 4 mg/liter finasteride with 2 mg/liter fluconazole. Finasteride inhibited filamentation, thus suggesting a potential mechanism of action. These results indicate that finasteride alone is highly active in the prevention of C. albicans urinary biofilms in vitro and has synergistic activity in combination with fluconazole. Further investigation of the clinical utility of finasteride in the prevention of urinary candidiasis is warranted. PMID:25049253
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Hope, Elyse A.; Dunham, Maitreya J.
2014-01-01
The ability of yeast to form biofilms contributes to better survival under stressful conditions. We see the impact of yeast biofilms and “flocs” (clumps) in human health and industry, where forming clumps enables yeast to act as a natural filter in brewing and forming biofilms enables yeast to remain virulent in cases of fungal infection. Despite the importance of biofilms in yeast natural isolates, the majority of our knowledge about yeast biofilm genetics comes from work with a few tractable laboratory strains. A new collection of sequenced natural isolates from the Saccharomyces Genome Resequencing Project enabled us to examine the breadth of biofilm-related phenotypes in geographically, ecologically, and genetically diverse strains of Saccharomyces cerevisiae. We present a panel of 31 haploid and 24 diploid strains for which we have characterized six biofilm-related phenotypes: complex colony morphology, complex mat formation, flocculation, agar invasion, polystyrene adhesion, and psuedohyphal growth. Our results show that there is extensive phenotypic variation between and within strains, and that these six phenotypes are primarily uncorrelated or weakly correlated, with the notable exception of complex colony and complex mat formation. We also show that the phenotypic strength of these strains varies significantly depending on ploidy, and the diploid strains demonstrate both decreased and increased phenotypic strength with respect to their haploid counterparts. This is a more complex view of the impact of ploidy on biofilm-related phenotypes than previous work with laboratory strains has suggested, demonstrating the importance and enormous potential of working with natural isolates of yeast. PMID:25060625
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Hope, Elyse A; Dunham, Maitreya J
2014-07-24
The ability of yeast to form biofilms contributes to better survival under stressful conditions. We see the impact of yeast biofilms and "flocs" (clumps) in human health and industry, where forming clumps enables yeast to act as a natural filter in brewing and forming biofilms enables yeast to remain virulent in cases of fungal infection. Despite the importance of biofilms in yeast natural isolates, the majority of our knowledge about yeast biofilm genetics comes from work with a few tractable laboratory strains. A new collection of sequenced natural isolates from the Saccharomyces Genome Resequencing Project enabled us to examine the breadth of biofilm-related phenotypes in geographically, ecologically, and genetically diverse strains of Saccharomyces cerevisiae. We present a panel of 31 haploid and 24 diploid strains for which we have characterized six biofilm-related phenotypes: complex colony morphology, complex mat formation, flocculation, agar invasion, polystyrene adhesion, and psuedohyphal growth. Our results show that there is extensive phenotypic variation between and within strains, and that these six phenotypes are primarily uncorrelated or weakly correlated, with the notable exception of complex colony and complex mat formation. We also show that the phenotypic strength of these strains varies significantly depending on ploidy, and the diploid strains demonstrate both decreased and increased phenotypic strength with respect to their haploid counterparts. This is a more complex view of the impact of ploidy on biofilm-related phenotypes than previous work with laboratory strains has suggested, demonstrating the importance and enormous potential of working with natural isolates of yeast. Copyright © 2014 Hope and Dunham.
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Mowat, Eilidh; Rajendran, Ranjith; Williams, Craig; McCulloch, Elaine; Jones, Brian; Lang, Sue; Ramage, Gordon
2010-12-01
Aspergillus fumigatus is often isolated from the lungs of cystic fibrosis (CF) patients, but unlike in severely immunocompromised individuals, the mortality rates are low. This suggests that competition from bacteria within the CF lung may be inhibitory. The purpose of this study was to investigate how Pseudomonas aeruginosa influences A. fumigatus conidial germination and biofilm formation. Aspergillus fumigatus biofilm formation was inhibited by direct contact with P. aeruginosa, but had no effect on preformed biofilm. A secreted heat-stable soluble factor was also shown to exhibit biofilm inhibition. Coculture of P. aeruginosa quorum-sensing mutants (PAO1:ΔLasI, PAO1:ΔLasR) did not significantly inhibit A. fumigatus biofilms (52.6-58.8%) to the same extent as that of the PA01 wild type (22.9-30.1%), both by direct and by indirect interaction (P<0.001). Planktonic and sessile inhibition assays with a series of short carbon chain molecules (decanol, decanoic acid and dodecanol) demonstrated that these molecules could both inhibit and disrupt biofilms in a concentration-dependent manner. Overall, this suggests that small diffusible and heat-stable molecules may be responsible for the competitive inhibition of filamentous fungal growth in polymicrobial environments such as the CF lung. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
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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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N-halamine-based rechargeable antimicrobial and biofilm-controlling polyurethane
Sun, Xinbo; Cao, Zhengbing; Porteous, Nuala; Sun, Yuyu
2012-01-01
An N-halamine precursor, 5, 5-dimethyl hydantoin (DMH), was covalently linked to the surface of polyurethane (PU) with 1,6-hexamethylene diisocyanate (HDI) as a coupling agent. The reaction pathways were investigated using propyl isocyanate (PI) as a model compound, and the results suggested that the imide and amide groups of DMH had very similar reactivity toward the isocyanate groups on PU surfaces activated with HDI. After bleach treatment, the covalently bound DMH moieties were transformed into N-halamines. The new N-halmaine-based PU provided potent antimicrobial effects against Staphylococcus aureus (S. aureus, Gram-positive), Escherichia coli (E. coli, Gram-negative), methicillin-resistant staphylococcus aureus (MRSA, drug resistant Gram-positive bacteria), vancomycin-resistant enterococcus (VRE, drug resistant Gram-positive bacteria), and Candida albicans (C. ablicans, fungi), and successfully prevented bacterial and fungal biofilm formation. The antimicrobial and biofilm-controlling effects were stable for longer than 6 months under normal storage in open air. Furthermore, if the functions were lost due to prolonged use, they could be recharged by another chlorination treatment. The recharging could be repeated as needed to achieve long-term protection against microbial contamination and biofilm-formation. PMID:22244984
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Murzyn, Anna; Krasowska, Anna; Stefanowicz, Piotr; Dziadkowiec, Dorota; Łukaszewicz, Marcin
2010-01-01
Candidiasis are life-threatening systemic fungal diseases, especially of gastro intestinal track, skin and mucous membranes lining various body cavities like the nostrils, the mouth, the lips, the eyelids, the ears or the genital area. Due to increasing resistance of candidiasis to existing drugs, it is very important to look for new strategies helping the treatment of such fungal diseases. One promising strategy is the use of the probiotic microorganisms, which when administered in adequate amounts confer a health benefit. Such a probiotic microorganism is yeast Saccharomyces boulardii, a close relative of baker yeast. Saccharomyces boulardii cells and their extract affect the virulence factors of the important human fungal pathogen C. albicans, its hyphae formation, adhesion and biofilm development. Extract prepared from S. boulardii culture filtrate was fractionated and GC-MS analysis showed that the active fraction contained, apart from 2-phenylethanol, caproic, caprylic and capric acid whose presence was confirmed by ESI-MS analysis. Biological activity was tested on C. albicans using extract and pure identified compounds. Our study demonstrated that this probiotic yeast secretes into the medium active compounds reducing candidal virulence factors. The chief compound inhibiting filamentous C. albicans growth comparably to S. boulardii extract was capric acid, which is thus responsible for inhibition of hyphae formation. It also reduced candidal adhesion and biofilm formation, though three times less than the extract, which thus contains other factors suppressing C. albicans adherence. The expression profile of selected genes associated with C. albicans virulence by real-time PCR showed a reduced expression of HWP1, INO1 and CSH1 genes in C. albicans cells treated with capric acid and S. boulardii extract. Hence capric acid secreted by S. boulardii is responsible for inhibition of C. albicans filamentation and partially also adhesion and biofilm formation. PMID
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Gao, Mei; Wang, Hui; Zhu, LiJuan
2016-01-01
Vulvovaginal candidiasis (VVC) is a common gynecological disease. Candida albicans is believed to be mainly implicated in VVC occurrence, the biofilm of which is one of the virulence factors responsible for resistance to traditional antifungal agents especially to fluconazole (FCZ). Quercetin (QCT) is a dietary flavonoid and has been demonstrated to be antifungal against C. albicans biofilm. 17 C. albicans isolates including 15 clinical ones isolated from VVC patients were employed to investigate the effects of QCT and/or FCZ on the inhibition of C. albicans biofilm. We observed that 64 µg/mL QCT and/or 128 µg/mL FCZ could (i) be synergistic against 10 FCZ-resistant planktonic and 17 biofilm cells of C. albicans, (ii) inhibit fungal adherence, cell surface hydrophobicity (CSH), flocculation, yeast-to-hypha transition, metabolism, thickness and dispersion of biofilms; (iii) down-regulate the expressions of ALS1, ALS3, HWP1, SUN41, UME6 and ECE1 and up-regulate the expressions of PDE2, NRG1 and HSP90, and we also found that (iv) the fungal burden was reduced in vaginal mucosa and the symptoms were alleviated in a murine VVC model after the treatments of 5 mg/kg QCT and/or 20 mg/kg FCZ. Together with these results, it could be demonstrated that QCT could be a favorable antifungal agent and a promising synergist with FCZ in the clinical management of VVC caused by C. albicans biofilm. © 2016 The Author(s) Published by S. Karger AG, Basel.
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Candida albicans-Induced Epithelial Damage Mediates Translocation through Intestinal Barriers
2018-01-01
ABSTRACT Life-threatening systemic infections often occur due to the translocation of pathogens across the gut barrier and into the bloodstream. While the microbial and host mechanisms permitting bacterial gut translocation are well characterized, these mechanisms are still unclear for fungal pathogens such as Candida albicans, a leading cause of nosocomial fungal bloodstream infections. In this study, we dissected the cellular mechanisms of translocation of C. albicans across intestinal epithelia in vitro and identified fungal genes associated with this process. We show that fungal translocation is a dynamic process initiated by invasion and followed by cellular damage and loss of epithelial integrity. A screen of >2,000 C. albicans deletion mutants identified genes required for cellular damage of and translocation across enterocytes. Correlation analysis suggests that hypha formation, barrier damage above a minimum threshold level, and a decreased epithelial integrity are required for efficient fungal translocation. Translocation occurs predominantly via a transcellular route, which is associated with fungus-induced necrotic epithelial damage, but not apoptotic cell death. The cytolytic peptide toxin of C. albicans, candidalysin, was found to be essential for damage of enterocytes and was a key factor in subsequent fungal translocation, suggesting that transcellular translocation of C. albicans through intestinal layers is mediated by candidalysin. However, fungal invasion and low-level translocation can also occur via non-transcellular routes in a candidalysin-independent manner. This is the first study showing translocation of a human-pathogenic fungus across the intestinal barrier being mediated by a peptide toxin. PMID:29871918
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Disinfection of Streptococcus mutans Biofilm by a Non-Thermal Atmospheric Plasma Brush
NASA Astrophysics Data System (ADS)
Hong, Qing; Dong, Xiaoqing; Chen, Meng; Xu, Yuanxi; Sun, Hongmin; Hong, Liang; Yu, Qingsong
2015-09-01
This study investigated the argon plasma treatment effect on disinfecting dental biofilm by using an atmospheric pressure plasma brush. S. mutans biofilms were developed for 3 days on the surfaces of hydroxyapatite discs, which were used to simulate human tooth enamel. After plasma treatment, cell viability in the S. mutans biofilms was characterized by using MTT assay and confocal laser scanning microscopy (CLSM). Compared with the untreated control group, about 90% and 95% bacterial reduction in the biofilms was observed after 1 and 5 min plasma treatment, respectively. Scanning electron microscopy examination indicated severe cell damages occurred on the top surface of the plasma treated biofilms. CLSM showed that plasma treatment was effective as deep as 20 μm into the biofilms. When combined with 0.2% chlorhexidine digluconate solution, the plasma treatment became more effective and over 96% bacterial reduction was observed with 1 min plasma treatment. These results indicate that plasma treatment is effective and promising in dental biofilm disinfection.
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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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[Influence of slime production and adhesion of Candida sp. on biofilm formation].
Ciok-Pater, Emilia; Smolak, Przemysław; Wróblewska, Joanna; Gospodarek, Eugenia
2011-01-01
The increase of fungal infections in recent years is connected with the progress in medicine. The vast usage of biomaterials is an inseparable element of contemporary medicine but it also leads to development of infections. Yeast-like fungi Candida albicans are still the main pathogen of candidiasis. The ability to slime production and adhesion to polystyrene of Candida sp. on different surfaces can cause to form biofilm on surfaces of biomaterials used in production of catheters, drains and prosthesis. The aim of the study was to evaluate the influence of slime production and adhesion to polystyrene, of Candida sp. on biofilm formation on different biomaterials. 50 strains of Candida sp. were examined. They isolated from ill to Clinics of Anesthesiology and Intensive Therapy University Hospital No 1 of dr. A. Jurasza in Bydgoszcz. The ability to slime production was evaluated by Christensen method in modification Davenport and Branchini methods. The adhesion to polystyrene was evaluated by Richards et el method. The ability to produce biofilm biomaterials by the studied fungi was measured after 72 hours of incubation at 37 degrees C on different biomaterials. Yeast-like fungi Candida sp. fabricating slime and adhesion forming frequently biofilm on surface researched of biomaterials. Influence of chosen biological specificity ascertain on the ability to produce biofilm on surfaces of siliconized latex and polyvinylchloride.
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Capillary-tube-based micro-plasma system for disinfecting dental biofilm.
Huang, Wen-Ke; Weng, Chih-Chiang; Liao, Jiunn-Der; Wang, Yi-Cheng; Chuang, Shu-Fen
2013-05-01
A low-temperature low-energy capillary-tube-based argon micro-plasma system was applied to disinfect Streptococcus mutans-containing biofilm. The micro-plasma system uses a hollow inner electrode that is ignited by a radio-frequency power supply with a matching network. The energy content was analyzed using optical emission spectroscopy. The micro-plasma-induced effect on a biofilm cultured for 24 or 48 h with a working distance of ≈3 mm at low temperature was evaluated. The morphologies of the treated live/dead bacteria and the produced polysaccharides after micro-plasma treatment were examined. Scanning electron microscopy images and staining results show that most of the S. mutans on the treated biofilm were acutely damaged within a micro-plasma treatment time of 300 s. The number of living bacteria underneath the treated biofilm greatly decreased with treatment time. The proposed micro-plasma system can thus disinfect S. mutans on/in biofilms.
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Baqué, Mickael; Scalzi, Giuliano; Rabbow, Elke; Rettberg, Petra; Billi, Daniela
2013-10-01
When Chroococcidiopsis sp. strain CCMEE 057 from the Sinai Desert and strain CCMEE 029 from the Negev Desert were exposed to space and Martian simulations in the dried status as biofilms or multilayered planktonic samples, the biofilms exhibited an enhanced rate of survival. Compared to strain CCMEE 029, biofilms of strain CCME 057 better tolerated UV polychromatic radiation (5 × 10(5) kJ/m(2) attenuated with a 0.1% neutral density filter) combined with space vacuum or Martian atmosphere of 780 Pa. CCMEE 029, on the other hand, failed to survive UV polychromatic doses higher than 1.5 × 10(3) kJ/m(2). The induced damage to genomic DNA, plasma membranes and photosynthetic apparatus was quantified and visualized by means of PCR-based assays and CLSM imaging. Planktonic samples of both strains accumulated a higher amount of damage than did the biofilms after exposure to each simulation; CLSM imaging showed that photosynthetic pigment bleaching, DNA fragmentation and damaged plasma membranes occurred in the top 3-4 cell layers of both biofilms and of multilayered planktonic samples. Differences in the EPS composition were revealed by molecular probe staining as contributing to the enhanced endurance of biofilms compared to that of planktonic samples. Our results suggest that compared to strain CCMEE 029, biofilms of strain CCMEE 057 might better tolerate 1 year's exposure in space during the next EXPOSE-R2 mission.
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NASA Astrophysics Data System (ADS)
Baqué, Mickael; Scalzi, Giuliano; Rabbow, Elke; Rettberg, Petra; Billi, Daniela
2013-10-01
When Chroococcidiopsis sp. strain CCMEE 057 from the Sinai Desert and strain CCMEE 029 from the Negev Desert were exposed to space and Martian simulations in the dried status as biofilms or multilayered planktonic samples, the biofilms exhibited an enhanced rate of survival. Compared to strain CCMEE 029, biofilms of strain CCME 057 better tolerated UV polychromatic radiation (5 × 105 kJ/m2 attenuated with a 0.1 % neutral density filter) combined with space vacuum or Martian atmosphere of 780 Pa. CCMEE 029, on the other hand, failed to survive UV polychromatic doses higher than 1.5 × 103 kJ/m2. The induced damage to genomic DNA, plasma membranes and photosynthetic apparatus was quantified and visualized by means of PCR-based assays and CLSM imaging. Planktonic samples of both strains accumulated a higher amount of damage than did the biofilms after exposure to each simulation; CLSM imaging showed that photosynthetic pigment bleaching, DNA fragmentation and damaged plasma membranes occurred in the top 3-4 cell layers of both biofilms and of multilayered planktonic samples. Differences in the EPS composition were revealed by molecular probe staining as contributing to the enhanced endurance of biofilms compared to that of planktonic samples. Our results suggest that compared to strain CCMEE 029, biofilms of strain CCMEE 057 might better tolerate 1 year's exposure in space during the next EXPOSE-R2 mission.
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Samaranayake, Y H; Cheung, B P K; Parahitiyawa, N; Seneviratne, C J; Yau, J Y Y; Yeung, K W S; Samaranayake, L P
2009-02-01
Denture related oral candidiasis is a recalcitrant fungal infection not easily resolved by topical antifungals. The antimycotic protein lysozyme, in saliva is an important host defense mechanism although its activity against Candida biofilms on denture acrylic has not been evaluated. (i) To establish a clinically relevant denture acrylic assay model to develop standardized Candida albicans biofilms, and (ii) assess the inhibitory effects of lysozyme alone and, the latter combined with antifungals (nystatin, amphotericin B, ketoconazole and 5-fluorocytosine) on sessile Candida cells and, finally (iii) to visualize the accompanying ultrastructural changes. The rotating-disc biofilm reactor was used to develop standardized 48 h Candida biofilms on acrylic discs in YNB/100 mM glucose medium and the biofilm metabolic activity was monitored using a tetrazolium reduction assay. The biofilm metabolic activity was similar in 18 identical denture acrylic discs (p<0.05) thus validating the rotating-disc biofilm model. Very low concentrations of lysozyme (6.25 microg/ml) significantly (p<0.01) inhibited Candida biofilm formation indicating that lysozyme may likely regulate intra-oral Candida biofilm development. Although 100 microg/ml lysozyme killed 45% of sessile Candida cells, further increasing its concentration (up to 240 microg/ml) had no such effect. Nystatin, amphotericin B, and ketoconazole in association with 100 microg/ml lysozyme exhibited effective synergistic killing of biofilm Candida in comparison to drug-free controls. Scanning electron and confocal scanning laser microscopy analysis confirmed the latter trends. Our results indicate that agents found in biological fluids such as lysozyme could be a safe adjunct to antifungals in future treatment strategies for recalcitrant candidal infections.
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Furiga, A; Roques, C; Badet, C
2014-04-01
To investigate the preventive effects of an original combination of a grape seed extract (GSE) with an amine fluoride (Fluorinol(®) ) on dental plaque formation and oxidative damage caused by oral bacteria. The antibacterial activity of the compounds was assessed using the broth macrodilution method, and their antiplaque activity was evaluated on a multispecies biofilm grown on saliva-coated hydroxyapatite discs. The effect on glucosyltransferases activity was analysed through reductions in the overall reaction and the quantity of insoluble glucan synthesized. The combination of 2000 μg ml(-1) of GSE with 10·2 mg ml(-1) of Fluorinol(®) significantly decreased the biofilm formation (up to 4·76 log10 of reduction) and inhibited by 97·4% the insoluble glucan synthesis by glucosyltransferases. The antioxidant activity of this combination, alone or incorporated into a formulated mouthwash (Eludril daily(®) ), was determined using the Trolox equivalent antioxidant capacity assay (TEAC), and both showed significantly greater antioxidant capacity than vitamin C. The GSE/Fluorinol(®) combination showed both a significant antiplaque activity and an important antioxidant capacity in vitro, without any bactericidal effects. This is, to our knowledge, the first report on the properties of an original combination of a polyphenolic extract with amine fluoride that could be used for the prevention of oral diseases and oxidative damage associated. © 2013 The Society for Applied Microbiology.
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Khan, Mohd Sajjad Ahmad; Ahmad, Iqbal
2012-03-27
Oils of Cymbopogon citratus and Syzygium aromaticum have been used in traditional medicine to treat fungal infections of skin, mouth, urinary and vaginal tract in Asian countries particularly India and other developing countries. To evaluate essential oils of Cymbopogon citratus and Syzygium aromaticum for their anti-biofilm activity against strong biofilm forming strains of Candida albicans. XTT reduction assay, Time kill assays, light microscopy and scanning electron microscopy (SEM) were employed to determine the effect of test oils on the Candida albicans biofilms. Most of the Candida albicans strains tested displayed formation of moderate to strong biofilms. Preformed Candida biofilms showed ≥1024 times increased resistance to antifungal drugs, 2 times to Syzygium aromaticum, but no increased tolerance for Cymbopogon citratus. Test oils were more active against preformed biofilms compared to amphotericin B and fluconazole. At 0.5× MIC, Cymbopogon citratus followed by Syzygium aromaticum were most inhibitory against biofilm formation. Light and electron microscopic studies revealed the deformity of three dimensional structures of biofilms formed in the presence of sub-MICs of Cymbopogon citratus. The cell membranes appeared to be the target site of compounds in sessile cells as displayed by SEM observations. Our data had demonstrated promising in vitro anti-biofilm activity by Cymbopogon citratus and Syzygium aromaticum and confirm the ethnopharmacological use of these oils in muco-cutaneous Candida infections. Furthermore, it suggests exploitation of these oils as new anti-biofilm products to deal with the problem of drug-resistance and recurrent infection associated with biofilm mode of growth of Candida spp. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
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Deng, Qi; Pu, Yuehua; Sun, Lijun; Wang, Yaling; Liu, Yang; Wang, Rundong; Liao, Jianmeng; Xu, Defeng; Liu, Ying; Ye, Riying; Fang, Zhijia; Gooneratne, Ravi
2017-12-01
Shewanella putrefaciens biofilm formation is of great concern for the shrimp industry because it adheres easily to food and food-contact surfaces and is a source of persistent and unseen contamination that causes shrimp spoilage and economic losses to the shrimp industry. Different concentrations of an antimicrobial lipopeptide, the fermentation product of Bacillus subtilis, AMPNT-6, were tested for the ability to reduce adhesion and disrupt S. putrefaciens preformed biofilms on two different contact surfaces (shrimp shell, stainless steel sheet). AMPNT-6 displayed a marked dose- and time-dependent anti-adhesive effect>biofilm removal. 3MIC AMPNT-6 was able both to remove biofilm and prevent bacteria from forming biofilm in a 96-well polystyrene microplate used as the model surface. 2MIC AMPNT-6 prevented bacteria from adhering to the microplate surface to form biofilm for 3h and removed already existing biofilm within 24h. Secretion of extracellular polymeric substances incubated in LB broth for 24h by S. putrefaciens was minimal at 3× MIC AMPNT-6. Scanning electron microscopy showed that damage to S. putrefaciens bacteria by AMPNT-6 possibly contributed to the non-adherence to the surfaces. Disruption of the mature biofilm structure by AMPNT-6 contributed to biofilm removal. It is concluded that AMPNT-6 can be used effectively to prevent attachment and also detach S. putrefaciens biofilms from shrimp shells, stainless steel sheets and polystyrene surfaces. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Disinfection of Streptococcus mutans biofilm by a non-thermal atmospheric plasma brush
NASA Astrophysics Data System (ADS)
Hong, Qing; Dong, Xiaoqing; Chen, Meng; Xu, Yuanxi; Sun, Hongmin; Hong, Liang; Wang, Yong; Yu, Qingsong
2016-07-01
This study investigated the argon plasma treatment effect on disinfecting dental biofilm by using an atmospheric pressure plasma brush. Streptococcus mutans biofilms were developed for 3 days on the surfaces of hydroxyapatite (HA) discs, which were used to simulate human tooth enamel. After plasma treatment, cell viability in the S. mutans biofilms was characterized by using 3-(4,5-dimethylazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and confocal laser scanning microscopy (CLSM). Compared with the untreated control group, about 90% bacterial reduction in the biofilms was observed after 1 min plasma treatment. Scanning electron microscopy (SEM) examination indicated severe cell damages occurred on the top surface of the plasma treated biofilms. Confocal laser scanning microscopy (CLSM) showed that plasma treatment was effective as deep as 20 µm into the biofilms. When combined with antibiotic treatment using 0.2% chlorhexidine digluconate solution, the plasma treatment became more effective and over 96% bacterial reduction was observed with 1 min plasma treatment.
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Alshami, Issam; Alharbi, Ahmed E
2014-02-01
To explore the prevention of recurrent candiduria using natural based approaches and to study the antimicrobial effect of Hibiscus sabdariffa (H. sabdariffa) extract and the biofilm forming capacity of Candida albicans strains in the present of the H. sabdariffa extract. In this particular study, six strains of fluconazole resistant Candida albicans isolated from recurrent candiduria were used. The susceptibility of fungal isolates, time-kill curves and biofilm forming capacity in the present of the H. sabdariffa extract were determined. Various levels minimum inhibitory concentration of the extract were observed against all the isolates. Minimum inhibitory concentration values ranged from 0.5 to 2.0 mg/mL. Time-kill experiment demonstrated that the effect was fungistatic. The biofilm inhibition assay results showed that H. sabdariffa extract inhibited biofilm production of all the isolates. The results of the study support the potential effect of H. sabdariffa extract for preventing recurrent candiduria and emphasize the significance of the plant extract approach as a potential antifungal agent.
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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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The role of biofilms: are we hitting the right target?
Wolcott, Randall; Dowd, Scot
2011-01-01
Chronic infections affect 17 million people yearly, and approximately 550,000 people die each year from, or with, their chronic infections. Acute and chornic infection differences are well known to clinicians, but the role of bacteria in producing these clinical differences remains poorly understood. This review relies on basic science, clinical studies, and a general review of the medical biofilm literature. The basic science studies are level A and B quality of evidence. The clinical studies are mainly retrospective cohort (level B) and case studies (level C). The biofilm literature includes reviews with varying levels of evidence. All articles have been peer reviewed and meet the standard of evidence-based medicine. Acute infections are associated with planktonic bacteria and must be diagnosed rapidly and accurately to prevent tissue damage and/or death. In contrast, biofilm behavior pursues a more parasitic course by producing sustained host hyperinflammation, with the biofilm feeding on plasma exudate. Chronic infections vacillate over long periods of time, responding only partially to antibiotics and reemerging once the antibiotics are withdrawn. Chronic wounds exhibit similar clinical behavior seen in other chronic infections and are associated with biofilm phenotype bacteria on their surface. Biofilm infections, such as chronic wounds, cannot be adequately diagnosed with current clinical cultures; therefore, molecular methods are necessary. Biofilm phenotype bacteria require multiple concurrent strategies, including débridement and targeted antibiofilm agents. Biofilm phenotype bacteria predominate on the surface of wounds, and biofilm-based management improves wound healing outcomes, indicating that biofilm is the right target for managing the bioburden barrier of chronic wounds.
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Harrison, Paul F.; Lo, Tricia L.; Quenault, Tara; Dagley, Michael J.; Bellousoff, Matthew; Powell, David R.; Beilharz, Traude H.; Traven, Ana
2015-01-01
The yeast Candida albicans is a human commensal and opportunistic pathogen. Although both commensalism and pathogenesis depend on metabolic adaptation, the regulatory pathways that mediate metabolic processes in C. albicans are incompletely defined. For example, metabolic change is a major feature that distinguishes community growth of C. albicans in biofilms compared to suspension cultures, but how metabolic adaptation is functionally interfaced with the structural and gene regulatory changes that drive biofilm maturation remains to be fully understood. We show here that the RNA binding protein Puf3 regulates a posttranscriptional mRNA network in C. albicans that impacts on mitochondrial biogenesis, and provide the first functional data suggesting evolutionary rewiring of posttranscriptional gene regulation between the model yeast Saccharomyces cerevisiae and C. albicans. A proportion of the Puf3 mRNA network is differentially expressed in biofilms, and by using a mutant in the mRNA deadenylase CCR4 (the enzyme recruited to mRNAs by Puf3 to control transcript stability) we show that posttranscriptional regulation is important for mitochondrial regulation in biofilms. Inactivation of CCR4 or dis-regulation of mitochondrial activity led to altered biofilm structure and over-production of extracellular matrix material. The extracellular matrix is critical for antifungal resistance and immune evasion, and yet of all biofilm maturation pathways extracellular matrix biogenesis is the least understood. We propose a model in which the hypoxic biofilm environment is sensed by regulators such as Ccr4 to orchestrate metabolic adaptation, as well as the regulation of extracellular matrix production by impacting on the expression of matrix-related cell wall genes. Therefore metabolic changes in biofilms might be intimately linked to a key biofilm maturation mechanism that ultimately results in untreatable fungal disease. PMID:26474309
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Candida albicans biofilms formed into catheters and probes and their resistance to amphotericin B.
Boucherit-Atmani, Z; Seddiki, S M L; Boucherit, K; Sari-Belkharoubi, L; Kunkel, D
2011-09-01
In Algeria, many bacterial biofilms have been studied but those of fungal origin, particularly those due to the yeast Candida albicans remained unidentified. The present study was performed at the Chabane Hamdoune hospital in Maghnia (Algeria), where 51 strains of C. albicans representing 16.94% of all taken samples were isolated. They were collected from catheters and probes used in different hospital services with variable rates; the most concerned service was ICU (40.74%) followed by gynecology department (17.39%), while general surgery came third (15.79%). Testing the antifungal property of amphotericin B (AmB) we showed clearly that the sessile cells of C. albicans were much more resistant than their planktonic counterparts (suspended cells), especially when the resistance increased during the different phases of biofilm formation until it reached its threshold at the ripening stage (at 48h). Furthermore, scanning electron microscopy of the isolated strains in the laboratory revealed the formation of biofilms on catheters by C. albicans. Surprisingly, observations revealed the presence of a new structure in these biofilms: a chlamydospore? Copyright © 2011 Elsevier Masson SAS. All rights reserved.
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Atomic Force Microscope Investigations of Bacterial Biofilms Treated with Gas Discharge Plasmas
NASA Astrophysics Data System (ADS)
Vandervoort, Kurt; Zelaya, Anna; Brelles-Marino, Graciela
2012-02-01
We present investigations of bacterial biofilms before and after treatment with gas discharge plasmas. Gas discharge plasmas represent a way to inactivate bacteria under conditions where conventional disinfection methods are often ineffective. These conditions involve biofilm communities, where bacteria grow embedded in an exopolysaccharide matrix, and cooperative interactions between cells make organisms less susceptible to standard inactivation methods. In this study, biofilms formed by the opportunistic bacterium Pseudomonas aeruginosa were imaged before and after plasma treatment using an atomic force microscope (AFM). Through AFM images and micromechanical measurements we observed bacterial morphological damage and reduced AFM tip-sample surface adhesion following plasma treatment.
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Maddula, V. S. R. K.; Pierson, E. A.; Pierson, L. S.
2008-01-01
Pseudomonas chlororaphis strain 30-84 is a plant-beneficial bacterium that is able to control take-all disease of wheat caused by the fungal pathogen Gaeumannomyces graminis var. tritici. The production of phenazines (PZs) by strain 30-84 is the primary mechanism of pathogen inhibition and contributes to the persistence of strain 30-84 in the rhizosphere. PZ production is regulated in part by the PhzR/PhzI quorum-sensing (QS) system. Previous flow cell analyses demonstrated that QS and PZs are involved in biofilm formation in P. chlororaphis (V. S. R. K. Maddula, Z. Zhang, E. A. Pierson, and L. S. Pierson III, Microb. Ecol. 52:289-301, 2006). P. chlororaphis produces mainly two PZs, phenazine-1-carboxylic acid (PCA) and 2-hydroxy-PCA (2-OH-PCA). In the present study, we examined the effect of altering the ratio of PZs produced by P. chlororaphis on biofilm formation and pathogen inhibition. As part of this study, we generated derivatives of strain 30-84 that produced only PCA or overproduced 2-OH-PCA. Using flow cell assays, we found that these PZ-altered derivatives of strain 30-84 differed from the wild type in initial attachment, mature biofilm architecture, and dispersal from biofilms. For example, increased 2-OH-PCA production promoted initial attachment and altered the three-dimensional structure of the mature biofilm relative to the wild type. Additionally, both alterations promoted thicker biofilm development and lowered dispersal rates compared to the wild type. The PZ-altered derivatives of strain 30-84 also differed in their ability to inhibit the fungal pathogen G. graminis var. tritici. Loss of 2-OH-PCA resulted in a significant reduction in the inhibition of G. graminis var. tritici. Our findings suggest that alterations in the ratios of antibiotic secondary metabolites synthesized by an organism may have complex and wide-ranging effects on its biology. PMID:18263718
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Novel role for the Streptococcus pneumoniae toxin pneumolysin in the assembly of biofilms.
Shak, Joshua R; Ludewick, Herbert P; Howery, Kristen E; Sakai, Fuminori; Yi, Hong; Harvey, Richard M; Paton, James C; Klugman, Keith P; Vidal, Jorge E
2013-09-10
. Pneumolysin is an important toxin produced by almost all S. pneumoniae strains, extensively studied for its ability to cause damage to human tissue. In this paper, we demonstrate that pneumolysin has a previously unrecognized role in biofilm formation by showing that strains without pneumolysin are unable to form the same amount of biofilm on plastic and human cell substrates. Furthermore, we show that the role of pneumolysin in biofilm formation is separate from the hemolytic activity responsible for tissue damage during pneumococcal diseases. This novel role for pneumolysin suggests that pneumococcal vaccines directed against this protein should be investigated for their potential impact on biofilms formed during carriage and disease.
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Trentin, Danielle S.; Silva, Denise B.; Amaral, Matheus W.; Zimmer, Karine R.; Silva, Márcia V.; Lopes, Norberto P.; Giordani, Raquel B.; Macedo, Alexandre J.
2013-01-01
Plants produce many compounds that are biologically active, either as part of their normal program of growth and development or in response to pathogen attack or stress. Traditionally, Anadenanthera colubrina, Commiphora leptophloeos and Myracrodruon urundeuva have been used by communities in the Brazilian Caatinga to treat several infectious diseases. The ability to impair bacterial adhesion represents an ideal strategy to combat bacterial pathogenesis, because of its importance in the early stages of the infectious process; thus, the search for anti-adherent compounds in plants is a very promising alternative. This study investigated the ability of stem-bark extracts from these three species to control the growth and prevent biofilm formation of Pseudomonas aeruginosa, an important opportunistic pathogen that adheres to surfaces and forms protective biofilms. A kinetic study (0–72 h) demonstrated that the growth of extract-treated bacteria was inhibited up to 9 h after incubation, suggesting a bacteriostatic activity. Transmission electron microscopy and fluorescence microscopy showed both viable and nonviable cells, indicating bacterial membrane damage; crystal violet assay and scanning electron microscopy demonstrated that treatment strongly inhibited biofilm formation during 6 and 24 h and that matrix production remained impaired even after growth was restored, at 24 and 48 h of incubation. Herein, we propose that the identified (condensed and hydrolyzable) tannins are able to inhibit biofilm formation via bacteriostatic properties, damaging the bacterial membrane and hindering matrix production. Our findings demonstrate the importance of this abundant class of Natural Products in higher plants against one of the most challenging issues in the hospital setting: biofilm resilience. PMID:23776646
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Nieminen, Mikko T.; Novak-Frazer, Lily; Rautemaa, Vilma; Rajendran, Ranjith; Sorsa, Timo; Ramage, Gordon; Bowyer, Paul; Rautemaa, Riina
2014-01-01
The ability of C. albicans to form biofilms is a major virulence factor and a challenge for management. This is evident in biofilm-associated chronic oral-oesophageal candidosis, which has been shown to be potentially carcinogenic in vivo. We have previously shown that most Candida spp. can produce significant levels of mutagenic acetaldehyde (ACH). ACH is also an important mediator of candidal biofilm formation. We have also reported that D,L-2-hydroxyisocaproic acid (HICA) significantly inhibits planktonic growth of C. albicans. The aim of the present study was to investigate the effect of HICA on C. albicans biofilm formation and ACH production in vitro. Inhibition of biofilm formation by HICA, analogous control compounds or caspofungin was measured using XTT to measure biofilm metabolic activity and PicoGreen as a marker of biomass. Biofilms were visualised by scanning electron microscopy (SEM). ACH levels were measured by gas chromatography. Transcriptional changes in the genes involved in ACH metabolism were measured using RT-qPCR. The mean metabolic activity and biomass of all pre-grown (4, 24, 48 h) biofilms were significantly reduced after exposure to HICA (p<0.05) with the largest reductions seen at acidic pH. Caspofungin was mainly active against biofilms pre-grown for 4 h at neutral pH. Mutagenic levels (>40 µM) of ACH were detected in 24 and 48 h biofilms at both pHs. Interestingly, no ACH production was detected from D-glucose in the presence of HICA at acidic pH (p<0.05). Expression of genes responsible for ACH catabolism was up-regulated by HICA but down-regulated by caspofungin. SEM showed aberrant hyphae and collapsed hyphal structures during incubation with HICA at acidic pH. We conclude that HICA has potential as an antifungal agent with ability to inhibit C. albicans cell growth and biofilm formation. HICA also significantly reduces the mutagenic potential of C. albicans biofilms, which may be important when treating bacterial-fungal biofilm
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Fungal degradation of fiber-reinforced composite materials
NASA Technical Reports Server (NTRS)
Gu, J. D.; Lu, C.; Mitchell, R.; Thorp, K.; Crasto, A.
1997-01-01
As described in a previous report, a fungal consortium isolated from degraded polymeric materials was capable of growth on presterilized coupons of five composites, resulting in deep penetration into the interior of all materials within five weeks. Data describing the utilization of composite constituents as nutrients for the microflora are described in this article. Increased microbial growth was observed when composite extract was incubated with the fungal inoculum at ambient temperatures. Scanning electron microscopic observation of carbon fibers incubated with a naturally developed population of microorganisms showed the formation of bacterial biofilms on the fiber surfaces, suggesting possible utilization of the fiber chemical sizing as carbon and energy sources. Electrochemical impedance spectroscopy was used to monitor the phenomena occurring at the fiber-matrix interfaces. Significant differences were observed between inoculated and sterile panels of the composite materials. A progressive decline in impedance was detected in the inoculated panels. Several reaction steps may be involved in the degradation process. Initial ingress of water into the resin matrix appeared to be followed by degradation of fiber surfaces, and separation of fibers from the resin matrix. This investigation suggested that composite materials are susceptible to microbial attack by providing nutrients for growth.
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Adhesins in Human Fungal Pathogens: Glue with Plenty of Stick
de Groot, Piet W. J.; Bader, Oliver; de Boer, Albert D.; Weig, Michael
2013-01-01
Understanding the pathogenesis of an infectious disease is critical for developing new methods to prevent infection and diagnose or cure disease. Adherence of microorganisms to host tissue is a prerequisite for tissue invasion and infection. Fungal cell wall adhesins involved in adherence to host tissue or abiotic medical devices are critical for colonization leading to invasion and damage of host tissue. Here, with a main focus on pathogenic Candida species, we summarize recent progress made in the field of adhesins in human fungal pathogens and underscore the importance of these proteins in establishment of fungal diseases. PMID:23397570
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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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Reichhardt, Courtney; Ferreira, Jose A G; Joubert, Lydia-Marie; Clemons, Karl V; Stevens, David A; Cegelski, Lynette
2015-11-01
Aspergillus fumigatus is commonly responsible for lethal fungal infections among immunosuppressed individuals. A. fumigatus forms biofilm communities that are of increasing biomedical interest due to the association of biofilms with chronic infections and their increased resistance to antifungal agents and host immune factors. Understanding the composition of microbial biofilms and the extracellular matrix is important to understanding function and, ultimately, to developing strategies to inhibit biofilm formation. We implemented a solid-state nuclear magnetic resonance (NMR) approach to define compositional parameters of the A. fumigatus extracellular matrix (ECM) when biofilms are formed in RPMI 1640 nutrient medium. Whole biofilm and isolated matrix networks were also characterized by electron microscopy, and matrix proteins were identified through protein gel analysis. The (13)C NMR results defined and quantified the carbon contributions in the insoluble ECM, including carbonyls, aromatic carbons, polysaccharide carbons (anomeric and nonanomerics), aliphatics, etc. Additional (15)N and (31)P NMR spectra permitted more specific annotation of the carbon pools according to C-N and C-P couplings. Together these data show that the A. fumigatus ECM produced under these growth conditions contains approximately 40% protein, 43% polysaccharide, 3% aromatic-containing components, and up to 14% lipid. These fundamental chemical parameters are needed to consider the relationships between composition and function in the A. fumigatus ECM and will enable future comparisons with other organisms and with A. fumigatus grown under alternate conditions. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
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A new mathematical model of bacterial interactions in two-species oral biofilms
Martin, Bénédicte; Tamanai-Shacoori, Zohreh; Bronsard, Julie; Ginguené, Franck; Meuric, Vincent
2017-01-01
Periodontitis are bacterial inflammatory diseases, where the bacterial biofilms present on the tooth-supporting tissues switch from a healthy state towards a pathogenic state. Among bacterial species involved in the disease, Porphyromonas gingivalis has been shown to induce dysbiosis, and to induce virulence of otherwise healthy bacteria like Streptococcus gordonii. During biofilm development, primary colonizers such as S. gordonii first attach to the surface and allow the subsequent adhesion of periodontal pathogens such as P. gingivalis. Interactions between those two bacteria have been extensively studied during the adhesion step of the biofilm. The aim of the study was to understand interactions of both species during the growing phase of the biofilm, for which little knowledge is available, using a mathematical model. This two-species biofilm model was based on a substrate-dependent growth, implemented with damage parameters, and validated thanks to data obtained on experimental biofilms. Three different hypothesis of interactions were proposed and assayed using this model: independence, competition between both bacteria species, or induction of toxicity by one species for the other species. Adequacy between experimental and simulated biofilms were found with the last hypothetic mathematical model. This new mathematical model of two species bacteria biofilms, dependent on different substrates for growing, can be applied to any bacteria species, environmental conditions, or steps of biofilm development. It will be of great interest for exploring bacterial interactions in biofilm conditions. PMID:28253369
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Tøndervik, Anne; Sletta, Håvard; Klinkenberg, Geir; Emanuel, Charlotte; Powell, Lydia C.; Pritchard, Manon F.; Khan, Saira; Craine, Kieron M.; Onsøyen, Edvar; Rye, Phil D.; Wright, Chris; Thomas, David W.; Hill, Katja E.
2014-01-01
The oligosaccharide OligoG, an alginate derived from seaweed, has been shown to have anti-bacterial and anti-biofilm properties and potentiates the activity of selected antibiotics against multi-drug resistant bacteria. The ability of OligoG to perturb fungal growth and potentiate conventional antifungal agents was evaluated using a range of pathogenic fungal strains. Candida (n = 11) and Aspergillus (n = 3) spp. were tested using germ tube assays, LIVE/DEAD staining, scanning electron microscopy (SEM), atomic force microscopy (AFM) and high-throughput minimum inhibition concentration assays (MICs). In general, the strains tested showed a significant dose-dependent reduction in cell growth at ≥6% OligoG as measured by optical density (OD600; P<0.05). OligoG (>0.5%) also showed a significant inhibitory effect on hyphal growth in germ tube assays, although strain-dependent variations in efficacy were observed (P<0.05). SEM and AFM both showed that OligoG (≥2%) markedly disrupted fungal biofilm formation, both alone, and in combination with fluconazole. Cell surface roughness was also significantly increased by the combination treatment (P<0.001). High-throughput robotic MIC screening demonstrated the potentiating effects of OligoG (2, 6, 10%) with nystatin, amphotericin B, fluconazole, miconazole, voriconazole or terbinafine with the test strains. Potentiating effects were observed for the Aspergillus strains with all six antifungal agents, with an up to 16-fold (nystatin) reduction in MIC. Similarly, all the Candida spp. showed potentiation with nystatin (up to 16-fold) and fluconazole (up to 8-fold). These findings demonstrate the antifungal properties of OligoG and suggest a potential role in the management of fungal infections and possible reduction of antifungal toxicity. PMID:25409186
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Alshami, Issam; Alharbi, Ahmed E
2014-01-01
Objective To explore the prevention of recurrent candiduria using natural based approaches and to study the antimicrobial effect of Hibiscus sabdariffa (H. sabdariffa) extract and the biofilm forming capacity of Candida albicans strains in the present of the H. sabdariffa extract. Methods In this particular study, six strains of fluconazole resistant Candida albicans isolated from recurrent candiduria were used. The susceptibility of fungal isolates, time-kill curves and biofilm forming capacity in the present of the H. sabdariffa extract were determined. Results Various levels minimum inhibitory concentration of the extract were observed against all the isolates. Minimum inhibitory concentration values ranged from 0.5 to 2.0 mg/mL. Time-kill experiment demonstrated that the effect was fungistatic. The biofilm inhibition assay results showed that H. sabdariffa extract inhibited biofilm production of all the isolates. Conclusions The results of the study support the potential effect of H. sabdariffa extract for preventing recurrent candiduria and emphasize the significance of the plant extract approach as a potential antifungal agent. PMID:25182280
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Mang, Thomas; Rogers, Stephen; Keinan, David; Honma, Kiyonobu; Baier, Robert
2016-03-01
Dental implants are commonly used today for the treatment of partially and fully edentulous patients. Despite the high success rate they are not resistant to complications and failure due to a variety of problems including peri-implantitis or peri-mucositis due to bacterial biofilm formation on the implant surface. The use of non-surgical and surgical treatment procedure to promote healing in cases with peri-implantitis have limited efficacy. Here we studied the ability of photodynamic therapy to destroy a known bacterial pathogen and the extracellular matrix architecture of biofilm attached to titanium plates and germanium prisms. Titanium plates or germanium prisms were incubated for 24h with Fusobacterium nucleatum a fusiform, gram-negative bacterium was used to enable biofilm formation. Photodynamic therapy was carried out by incubating the biofilm samples on each substrata with porfimer sodium. Treatment was carried out using a diode laser at 630nm, 150mW/cm(2) for light doses ranging from 25-100J/cm(2). Evaluation of killing efficacy was done by counting colony forming units compared to controls. Multiple attenuated internal reflection-infrared spectroscopy (MAIR-IR) and SEM were used to analyze the samples pre and post PDT for validation. F. nucleatum was significantly reduced in a dose dependent manner by treatment with PDT. Changes in biofilm components and strength of bioadhesion were examined with MAIR-IR following jet impingement using calibrated water jets. SEM demonstrates significant morphological alterations in the bacteria, consistent with damage associated with exposure to reactive oxygen species. The results are indicative that aPDT is a method that can be used to eradicate micro-organisms associated with biofilm in peri-implantitis on relevant substrata. Data shows that the slime layer of the biofilm is removed and that further methods need to be employed to completely remove weakened or destroyed biofilm matrix components. Reactive oxygen
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Cavalcanti, Indira M G; Nobbs, Angela H; Ricomini-Filho, Antônio Pedro; Jenkinson, Howard F; Del Bel Cury, Altair A
2016-04-01
Candida-associated stomatitis affects up to 60% of denture wearers, and Candida albicans remains the most commonly isolated fungal species. The oral bacteria Actinomyces oris and Streptococcus oralis are abundant in early dental plaque. The aims of this study were to determine the effects of S. oralis and A. oris on the development of C. albicans biofilms on denture material. Resin discs were coated with saliva and at early (1.5 h) or later (24 h) stages of biofilm development, cell numbers of each species were determined. Spatial distribution of microorganisms was visualized by confocal scanning laser microscopy of biofilms labelled by differential fluorescence or by fluorescence in situ hybridization. Interkingdom interactions underpinning biofilm development were also evaluated planktonically utilizing fluorescence microscopy. Synergistic interactions between all three species occurred within biofilms and planktonically. Bacterial cells coaggregated with each other and adhered singly or in coaggregates to C. albicans hyphal filaments. Streptococcus oralis appeared to enhance hyphal filament production and C. albicans biovolume was increased 2-fold. Concomitantly, cell numbers of S. oralis and A. oris were enhanced by C. albicans. Thus, cooperative physical and metabolic processes occurring between these three microbial species intensify pathogenic plaque communities on denture surfaces. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Salmonella biofilm formation on Aspergillus niger involves cellulose--chitin interactions.
Brandl, Maria T; Carter, Michelle Q; Parker, Craig T; Chapman, Matthew R; Huynh, Steven; Zhou, Yaguang
2011-01-01
Salmonella cycles between host and nonhost environments, where it can become an active member of complex microbial communities. The role of fungi in the environmental adaptation of enteric pathogens remains relatively unexplored. We have discovered that S. enterica Typhimurium rapidly attaches to and forms biofilms on the hyphae of the common fungus, Aspergillus niger. Several Salmonella enterica serovars displayed a similar interaction, whereas other bacterial species were unable to bind to the fungus. Bacterial attachment to chitin, a major constituent of fungal cell walls, mirrored this specificity. Pre-incubation of S. Typhimurium with N-acetylglucosamine, the monomeric component of chitin, reduced binding to chitin beads by as much as 727-fold and inhibited attachment to A. niger hyphae considerably. A cellulose-deficient mutant of S. Typhimurium failed to attach to chitin beads and to the fungus. Complementation of this mutant with the cellulose operon restored binding to chitin beads to 79% of that of the parental strain and allowed for attachment and biofilm formation on A. niger, indicating that cellulose is involved in bacterial attachment to the fungus via the chitin component of its cell wall. In contrast to cellulose, S. Typhimurium curli fimbriae were not required for attachment and biofilm development on the hyphae but were critical for its stability. Our results suggest that cellulose-chitin interactions are required for the production of mixed Salmonella-A. niger biofilms, and support the hypothesis that encounters with chitinaceous alternate hosts may contribute to the ecological success of human pathogens.
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Holland, Linda M.; Schröder, Markus S.; Turner, Siobhán A.; Taff, Heather; Andes, David; Grózer, Zsuzsanna; Gácser, Attila; Ames, Lauren; Haynes, Ken; Higgins, Desmond G.; Butler, Geraldine
2014-01-01
Candida parapsilosis and Candida albicans are human fungal pathogens that belong to the CTG clade in the Saccharomycotina. In contrast to C. albicans, relatively little is known about the virulence properties of C. parapsilosis, a pathogen particularly associated with infections of premature neonates. We describe here the construction of C. parapsilosis strains carrying double allele deletions of 100 transcription factors, protein kinases and species-specific genes. Two independent deletions were constructed for each target gene. Growth in >40 conditions was tested, including carbon source, temperature, and the presence of antifungal drugs. The phenotypes were compared to C. albicans strains with deletions of orthologous transcription factors. We found that many phenotypes are shared between the two species, such as the role of Upc2 as a regulator of azole resistance, and of CAP1 in the oxidative stress response. Others are unique to one species. For example, Cph2 plays a role in the hypoxic response in C. parapsilosis but not in C. albicans. We found extensive divergence between the biofilm regulators of the two species. We identified seven transcription factors and one protein kinase that are required for biofilm development in C. parapsilosis. Only three (Efg1, Bcr1 and Ace2) have similar effects on C. albicans biofilms, whereas Cph2, Czf1, Gzf3 and Ume6 have major roles in C. parapsilosis only. Two transcription factors (Brg1 and Tec1) with well-characterized roles in biofilm formation in C. albicans do not have the same function in C. parapsilosis. We also compared the transcription profile of C. parapsilosis and C. albicans biofilms. Our analysis suggests the processes shared between the two species are predominantly metabolic, and that Cph2 and Bcr1 are major biofilm regulators in C. parapsilosis. PMID:25233198
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You, Jianlan; Du, Lin; King, Jarrod B.; Hall, Brian E.; Cichewicz, Robert H.
2013-01-01
A new class of fungal biofilm inhibitors represented by shearinines D (3) and E (4) were obtained from a Penicillium sp. isolate. The inhibitory activities of 3 and 4 were characterized using a new imaging flow-cytometer technique, which enabled the rapid phenotypic analysis of Candida albicans cell types (budding yeast cells, germ tube cells, pseudohyphae, and hyphae) in biofilms populations. The results were confirmed by experimental data obtained from three-dimensional confocal laser scanning microscopy and 2,3- bis-(2-methoxy-4- nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assays. These data indicate that 3 and 4 inhibited C. albicans biofilm formation by blocking the outgrowth of hyphae at a relatively late stage of biofilm development (IC50 = 8.5 μM and 7.6 μM, respectively). However, 3 and 4 demonstrated comparatively weak activity at disrupting existing biofilms. Compounds 3 and 4 also exhibited synergistic activities with amphotericin B against C. albicans and others clinical Candida isolates by enhancing the potency of amphotericin B up to eight-fold against cells in both developing and established biofilms. These data suggest that the Candida biofilm disruption and amphotericin B potentiating effects of 3 and 4 could be mediated through multiple biological targets. The shearinines are good tools for testing the potential advantages of using adjunctive therapies in combination with antifungals. PMID:23387427
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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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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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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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Franks, A; Egan, S; Holmström, C; James, S; Lappin-Scott, H; Kjelleberg, S
2006-09-01
The marine epiphytic bacterium Pseudoalteromonas tunicata produces a range of extracellular secondary metabolites that inhibit an array of common fouling organisms, including fungi. In this study, we test the hypothesis that the ability to inhibit fungi provides P. tunicata with an advantage during colonization of a surface. Studies on a transposon-generated antifungal-deficient mutant of P. tunicata, FM3, indicated that a long-chain fatty acid-coenzyme A ligase is involved in the production of a broad-range antifungal compound by P. tunicata. Flow cell experiments demonstrated that production of an antifungal compound provided P. tunicata with a competitive advantage against a marine yeast isolate during surface colonization. This compound enabled P. tunicata to disrupt an already established fungal biofilm by decreasing the number of yeast cells attached to the surface by 66% +/- 9%. For in vivo experiments, the wild-type and FM3 strains of P. tunicata were used to inoculate the surface of the green alga Ulva australis. Double-gradient denaturing gradient gel electrophoresis analysis revealed that after 48 h, the wild-type P. tunicata had outcompeted the surface-associated fungal community, whereas the antifungal-deficient mutant had no effect on the fungal community. Our data suggest that P. tunicata is an effective competitor against fungal surface communities in the marine environment.
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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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Biofilm attachment reduction on bioinspired, dynamic, micro-wrinkling surfaces
NASA Astrophysics Data System (ADS)
Epstein, Alexander K.; Hong, Donggyoon; Kim, Philseok; Aizenberg, Joanna
2013-09-01
Most bacteria live in multicellular communities known as biofilms that are adherent to surfaces in our environment, from sea beds to plumbing systems. Biofilms are often associated with clinical infections, nosocomial deaths and industrial damage such as bio-corrosion and clogging of pipes. As mature biofilms are extremely challenging to eradicate once formed, prevention is advantageous over treatment. However, conventional surface chemistry strategies are either generally transient, due to chemical masking, or toxic, as in the case of leaching marine antifouling paints. Inspired by the nonfouling skins of echinoderms and other marine organisms, which possess highly dynamic surface structures that mechanically frustrate bio-attachment, we have developed and tested a synthetic platform based on both uniaxial mechanical strain and buckling-induced elastomer microtopography. Bacterial biofilm attachment to the dynamic substrates was studied under an array of parameters, including strain amplitude and timescale (1-100 mm s-1), surface wrinkle length scale, bacterial species and cell geometry, and growth time. The optimal conditions for achieving up to ˜ 80% Pseudomonas aeruginosa biofilm reduction after 24 h growth and ˜ 60% reduction after 48 h were combinatorially elucidated to occur at 20% strain amplitude, a timescale of less than ˜ 5 min between strain cycles and a topography length scale corresponding to the cell dimension of ˜ 1 μm. Divergent effects on the attachment of P. aeruginosa, Staphylococcus aureus and Escherichia coli biofilms showed that the dynamic substrate also provides a new means of species-specific biofilm inhibition, or inversely, selection for a desired type of bacteria, without reliance on any toxic or transient surface chemical treatments.
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Troskie, Anscha Mari; Rautenbach, Marina; Delattin, Nicolas; Vosloo, Johan Arnold; Dathe, Margitta; Thevissen, Karin
2014-01-01
Tyrocidines are cationic cyclodecapeptides from Bacillus aneurinolyticus that are characterized by potent antibacterial and antimalarial activities. In this study, we show that various tyrocidines have significant activity against planktonic Candida albicans in the low-micromolar range. These tyrocidines also prevented C. albicans biofilm formation in vitro. Studies with the membrane-impermeable dye propidium iodide showed that the tyrocidines disrupt the membrane integrity of mature C. albicans biofilm cells. This membrane activity correlated with the permeabilization and rapid lysis of model fungal membranes containing phosphatidylcholine and ergosterol (70:30 ratio) induced by the tyrocidines. The tyrocidines exhibited pronounced synergistic biofilm-eradicating activity in combination with two key antifungal drugs, amphotericin B and caspofungin. Using a Caenorhabditis elegans infection model, we found that tyrocidine A potentiated the activity of caspofungin. Therefore, tyrocidines are promising candidates for further research as antifungal drugs and as agents for combinatorial treatment. PMID:24752256
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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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Folwell, Benjamin D.
2016-01-01
High-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs) are natural components of fossil fuels that are carcinogenic and persistent in the environment, particularly in oil sands process-affected water (OSPW). Their hydrophobicity and tendency to adsorb to organic matter result in low bioavailability and high recalcitrance to degradation. Despite the importance of microbes for environmental remediation, little is known about those involved in HMW-PAH transformations. Here, we investigated the transformation of HMW-PAHs using samples of OSPW and compared the bacterial and fungal community compositions attached to hydrophobic filters and in suspension. It was anticipated that the hydrophobic filters with sorbed HMW-PAHs would select for microbes that specialize in adhesion. Over 33 days, more pyrene was removed (75% ± 11.7%) than the five-ring PAHs benzo[a]pyrene (44% ± 13.6%) and benzo[b]fluoranthene (41% ± 12.6%). For both bacteria and fungi, the addition of PAHs led to a shift in community composition, but thereafter the major factor determining the fungal community composition was whether it was in the planktonic phase or attached to filters. In contrast, the major determinant of the bacterial community composition was the nature of the PAH serving as the carbon source. The main bacteria enriched by HMW-PAHs were Pseudomonas, Bacillus, and Microbacterium species. This report demonstrates that OSPW harbors microbial communities with the capacity to transform HMW-PAHs. Furthermore, the provision of suitable surfaces that encourage PAH sorption and microbial adhesion select for different fungal and bacterial species with the potential for HMW-PAH degradation. PMID:26850299
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Kusumi, Asako; Li, Xianshu; Osuga, Yu; Kawashima, Arata; Gu, Ji-Dong; Nasu, Masao; Katayama, Yoko
2013-01-01
The Bayon temple in Angkor Thom, Cambodia has shown serious deterioration and is subject to the formation of various pigmented biofilms. Because biofilms are damaging the bas-reliefs, low reliefs engraved on the surface of sandstone, information about the microbial community within them is indispensable to control biofilm colonization. PCR-denaturing gradient gel electrophoresis (DGGE) analysis of biofilm samples from the pigmented sandstone surfaces showed that the bacterial community members in the biofilms differed clearly from those in the air and had low sequence similarity to database sequences. Non-destructive sampling of biofilm revealed novel bacterial groups of predominantly Rubrobacter in salmon pink biofilm, Cyanobacteria in chrome green biofilm, Cyanobacteria and Chloroflexi in signal violet biofilm, Chloroflexi in black gray biofilm, and Deinococcus-Thermus, Cyanobacteria, and Rubrobacter in blue green biofilm. Serial peeling-off of a thick biofilm by layers with adhesive sheets revealed a stratified structure: the blue-green biofilm, around which there was serious deterioration, was very rich in Cyanobacteria near the surface and Chloroflexi in deep layer below. Nitrate ion concentrations were high in the blue-green biofilm. The characteristic distribution of bacteria at different biofilm depths provides valuable information on not only the biofilm formation process but also the sandstone weathering process in the tropics.
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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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Sun, Mengjun; Dong, Jiachen; Xia, Yiru; Shu, Rong
2017-06-01
The aim of this study was to evaluate the potential antibacterial activities of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) against planktonic and biofilm modes of Streptococcus mutans (S. mutans). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. The effects on planktonic growth and biofilm metabolic activity were evaluated by growth curve determination and MTT assay, respectively. Then, colony forming unit (CFU) counting, scanning electron microscopy (SEM) and real-time PCR were performed to further investigate the actions of DHA and EPA on exponential phase-S. mutans. Confocal laser scanning microscopy (CLSM) was used to detect the influences on mature biofilms. The MICs of DHA and EPA against S. mutans were 100 μM and 50 μM, respectively; the MBC of both compounds was 100 μM. In the presence of 12.5 μM-100 μM DHA or EPA, the planktonic growth and biofilm metabolic activity were reduced in varying degrees. For exponential-phase S. mutans, the viable counts, the bacterial membranes and the biofilm-associated gene expression were damaged by 100 μM DHA or EPA treatment. For 1-day-old biofilms, the thickness was decreased and the proportion of membrane-damaged bacteria was increased in the presence of 100 μM DHA or EPA. These results indicated that, DHA and EPA possessed antibacterial activities against planktonic and biofilm growing S. mutans. Copyright © 2017 Elsevier Ltd. All rights reserved.
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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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Salmonella Biofilm Formation on Aspergillus niger Involves Cellulose – Chitin Interactions
Brandl, Maria T.; Carter, Michelle Q.; Parker, Craig T.; Chapman, Matthew R.; Huynh, Steven; Zhou, Yaguang
2011-01-01
Salmonella cycles between host and nonhost environments, where it can become an active member of complex microbial communities. The role of fungi in the environmental adaptation of enteric pathogens remains relatively unexplored. We have discovered that S. enterica Typhimurium rapidly attaches to and forms biofilms on the hyphae of the common fungus, Aspergillus niger. Several Salmonella enterica serovars displayed a similar interaction, whereas other bacterial species were unable to bind to the fungus. Bacterial attachment to chitin, a major constituent of fungal cell walls, mirrored this specificity. Pre-incubation of S. Typhimurium with N-acetylglucosamine, the monomeric component of chitin, reduced binding to chitin beads by as much as 727-fold and inhibited attachment to A. niger hyphae considerably. A cellulose-deficient mutant of S. Typhimurium failed to attach to chitin beads and to the fungus. Complementation of this mutant with the cellulose operon restored binding to chitin beads to 79% of that of the parental strain and allowed for attachment and biofilm formation on A. niger, indicating that cellulose is involved in bacterial attachment to the fungus via the chitin component of its cell wall. In contrast to cellulose, S. Typhimurium curli fimbriae were not required for attachment and biofilm development on the hyphae but were critical for its stability. Our results suggest that cellulose–chitin interactions are required for the production of mixed Salmonella-A. niger biofilms, and support the hypothesis that encounters with chitinaceous alternate hosts may contribute to the ecological success of human pathogens. PMID:22003399
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Menkis, Audrius; Marčiulynas, Adas; Gedminas, Artūras; Lynikienė, Jūratė; Povilaitienė, Aistė
2015-11-01
The aim of this study was to assess the diversity and composition of fungal communities in damaged and undamaged shoots of Norway spruce (Picea abies) following recent invasion of the spruce bud scale (Physokermes piceae) in Lithuania. Sampling was done in July 2013 and included 50 random lateral shoots from ten random trees in each of five visually undamaged and five damaged 40-50-year-old pure stands of P. abies. DNA was isolated from 500 individual shoots, subjected to amplification of the internal transcribed spacer of fungal ribosomal DNA (ITS rDNA), barcoded and sequenced. Clustering of 149,426 high-quality sequences resulted in 1193 non-singleton contigs of which 1039 (87.1 %) were fungal. In total, there were 893 fungal taxa in damaged shoots and 608 taxa in undamaged shoots (p < 0.0001). Furthermore, 431 (41.5 %) fungal taxa were exclusively in damaged shoots, 146 (14.0 %) were exclusively in undamaged shoots, and 462 (44.5 %) were common to both types of samples. Correspondence analysis showed that study sites representing damaged and undamaged shoots were separated from each other, indicating that in these fungal communities, these were largely different and, therefore, heavily affected by P. piceae. In conclusion, the results demonstrated that invasive alien tree pests may have a profound effect on fungal mycobiota associated with the phyllosphere of P. abies, and therefore, in addition to their direct negative effect owing physical damage of the tissue, they may also indirectly determine health, sustainability and, ultimately, distribution of the forest tree species.
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Fish, Katherine E; Collins, Richard; Green, Nicola H; Sharpe, Rebecca L; Douterelo, Isabel; Osborn, A Mark; Boxall, Joby B
2015-01-01
Within drinking water distribution systems (DWDS), microorganisms form multi-species biofilms on internal pipe surfaces. A matrix of extracellular polymeric substances (EPS) is produced by the attached community and provides structure and stability for the biofilm. If the EPS adhesive strength deteriorates or is overcome by external shear forces, biofilm is mobilised into the water potentially leading to degradation of water quality. However, little is known about the EPS within DWDS biofilms or how this is influenced by community composition or environmental parameters, because of the complications in obtaining biofilm samples and the difficulties in analysing EPS. Additionally, although biofilms may contain various microbial groups, research commonly focuses solely upon bacteria. This research applies an EPS analysis method based upon fluorescent confocal laser scanning microscopy (CLSM) in combination with digital image analysis (DIA), to concurrently characterize cells and EPS (carbohydrates and proteins) within drinking water biofilms from a full-scale DWDS experimental pipe loop facility with representative hydraulic conditions. Application of the EPS analysis method, alongside DNA fingerprinting of bacterial, archaeal and fungal communities, was demonstrated for biofilms sampled from different positions around the pipeline, after 28 days growth within the DWDS experimental facility. The volume of EPS was 4.9 times greater than that of the cells within biofilms, with carbohydrates present as the dominant component. Additionally, the greatest proportion of EPS was located above that of the cells. Fungi and archaea were established as important components of the biofilm community, although bacteria were more diverse. Moreover, biofilms from different positions were similar with respect to community structure and the quantity, composition and three-dimensional distribution of cells and EPS, indicating that active colonisation of the pipe wall is an important
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Fish, Katherine E.; Collins, Richard; Green, Nicola H.; Sharpe, Rebecca L.; Douterelo, Isabel; Osborn, A. Mark; Boxall, Joby B.
2015-01-01
Within drinking water distribution systems (DWDS), microorganisms form multi-species biofilms on internal pipe surfaces. A matrix of extracellular polymeric substances (EPS) is produced by the attached community and provides structure and stability for the biofilm. If the EPS adhesive strength deteriorates or is overcome by external shear forces, biofilm is mobilised into the water potentially leading to degradation of water quality. However, little is known about the EPS within DWDS biofilms or how this is influenced by community composition or environmental parameters, because of the complications in obtaining biofilm samples and the difficulties in analysing EPS. Additionally, although biofilms may contain various microbial groups, research commonly focuses solely upon bacteria. This research applies an EPS analysis method based upon fluorescent confocal laser scanning microscopy (CLSM) in combination with digital image analysis (DIA), to concurrently characterize cells and EPS (carbohydrates and proteins) within drinking water biofilms from a full-scale DWDS experimental pipe loop facility with representative hydraulic conditions. Application of the EPS analysis method, alongside DNA fingerprinting of bacterial, archaeal and fungal communities, was demonstrated for biofilms sampled from different positions around the pipeline, after 28 days growth within the DWDS experimental facility. The volume of EPS was 4.9 times greater than that of the cells within biofilms, with carbohydrates present as the dominant component. Additionally, the greatest proportion of EPS was located above that of the cells. Fungi and archaea were established as important components of the biofilm community, although bacteria were more diverse. Moreover, biofilms from different positions were similar with respect to community structure and the quantity, composition and three-dimensional distribution of cells and EPS, indicating that active colonisation of the pipe wall is an important
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Effect of sodium hypochlorite on typical biofilms formed in drinking water distribution systems.
Lin, Huirong; Zhu, Xuan; Wang, Yuxin; Yu, Xin
2017-04-01
Human health and biological safety problems resulting from urban drinking water pipe network biofilms pollution have attracted wide concern. Despite the inclusion of residual chlorine in drinking water distribution systems supplies, the bacterium is a recalcitrant human pathogen capable of forming biofilms on pipe walls and causing health risks. Typical drinking water bacterial biofilms and their response to different concentrations of chlorination was monitored. The results showed that the four bacteria all formed single biofilms susceptible to sodium hypochlorite. After 30 min disinfection, biomass and cultivability decreased with increasing concentration of disinfectant but then increased in high disinfectant doses. PMA-qPCR results indicated that it resulted in little cellular damage. Flow cytometry analysis showed that with increasing doses of disinfectant, the numbers of clusters increased and the sizes of clusters decreased. Under high disinfectant treatment, EPS was depleted by disinfectant and about 0.5-1 mg/L of residual chlorine seemed to be appropriate for drinking water treatment. This research provides an insight into the EPS protection to biofilms. Resistance of biofilms against high levels of chlorine has implications for the delivery of drinking water.
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Hover, Tal; Maya, Tal; Ron, Sapir; Sandovsky, Hani; Shadkchan, Yana; Kijner, Nitzan; Mitiagin, Yulia; Fichtman, Boris; Harel, Amnon; Shanks, Robert M. Q.; Bruna, Roberto E.; García-Véscovi, Eleonora
2016-01-01
We have found a remarkable capacity for the ubiquitous Gram-negative rod bacterium Serratia marcescens to migrate along and kill the mycelia of zygomycete molds. This migration was restricted to zygomycete molds and several basidiomycete species. No migration was seen on any molds of the phylum Ascomycota. S. marcescens migration did not require fungal viability or surrounding growth medium, as bacteria migrated along aerial hyphae as well. S. marcescens did not exhibit growth tropism toward zygomycete mycelium. Bacterial migration along hyphae proceeded only when the hyphae grew into the bacterial colony. S. marcescens cells initially migrated along the hyphae, forming attached microcolonies that grew and coalesced to generate a biofilm that covered and killed the mycelium. Flagellum-defective strains of S. marcescens were able to migrate along zygomycete hyphae, although they were significantly slower than the wild-type strain and were delayed in fungal killing. Bacterial attachment to the mycelium does not necessitate type 1 fimbrial adhesion, since mutants defective in this adhesin migrated equally well as or faster than the wild-type strain. Killing does not depend on the secretion of S. marcescens chitinases, as mutants in which all three chitinase genes were deleted retained wild-type killing abilities. A better understanding of the mechanisms by which S. marcescens binds to, spreads on, and kills fungal hyphae might serve as an excellent model system for such interactions in general; fungal killing could be employed in agricultural fungal biocontrol. PMID:26896140
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Airway toxicity of house dust and its fungal composition.
Piecková, Elena; Wilkins, Ken
2004-01-01
House dust is an important source of different toxic metabolites as well as allergens, including those of fungal origin, in the indoor environment. A bio-assay employing 1-day-old chick tracheas was used to characterize airway effects of 2-butanone and dimethylsulphoxide (Me2SO) extracts of 23 dust samples collected from water damaged (13) and control (10) Danish schools. Direct microscopical analysis of samples, followed by cultivation on dichloran 18 % glycerol agar at 25 degrees C for 10 days to establish their mycoflora, was performed. The in vitro ciliostatic potential of the chloroform-extractable endo- and exometabolites of 41 representative fungal isolates was determined. Nine dust extracts in 2-butanone (2 from damp rooms) or 10 (6) in Me(2)SO showed some ciliostatic activity in the 3-days' experiment. Fungal composition of dust from buildings with leakage was almost identical with that from undamaged houses, as well as the fungal colony counts from the damp schools and the control samples. Aspergillus spp. were prevalent in the samples - 31 or 40 % of all fungi, followed by Penicillium spp. and Cladosporium cladosporioides. Alternaria spp., Chaetomium spp., Mucor spp., Mycelia sterilia, Paecilomyces variotii, Rhizopus sp., Ulocladium sp. and yeasts were each isolated in less than 8 % of the fungal content. No Aspergillus flavus isolate (8 in total) was aflatoxigenic,em>in vitro. Alternaria spp., Aspergillus spp., Botrytis cinerea, Penicillium spp., C. cladosporioides, Chaetomium spp. and Ulocladium sp.; in total, 88 % of all fungi tested, produced ciliostatically active metabolites. These toxigenic strains were also present in 4 dust samples from controls and 5 dust samples from water damaged buildings. Extracts of these dust samples were also toxic in bioassay. There were bio-detectable concentrations (10-20 microg of extracts/ml of the organ culture medium) of toxic compounds in house dust. Contribution of fungal metabolites to its toxic effect should
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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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Chemotaxis in P. Aeruginosa Biofilm Formation
NASA Astrophysics Data System (ADS)
Bienvenu, Samuel; Strain, Shinji; Thatcher, Travis; Gordon, Vernita
2010-10-01
Pseudomonas biofilms form infections in the lungs of Cystic Fibrosis (CF) patients that damage lung tissue and lead to death. Previous work shows chemotaxis is important for Pseudomonas in CF lungs. The work studied swimming bacteria at high concentrations. In contrast, medically relevant biofilms initiate from sparse populations of surface-bound bacteria. The recent development of software techniques for automated, high-throughput bacteria tracking leaves us well-poised to quantitatively study these chemotactic conditions. We will develop experimental systems for such studies, focusing on L-Arginine (an amino acid), D-Galactose (a sugar present in lungs), and succinate and glucose (carbon sources for bacteria). This suite of chemoattractants will allow us to study how chemoattractant characteristics--size and diffusion behavior--change bacterial response; the interaction of competing chemoattractants; and, differences in bacterial behaviors, like motility modes, in response to different types of chemoattractions and varying neighbor cell density.
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Monteiro, D R; Silva, S; Negri, M; Gorup, L F; de Camargo, E R; Oliveira, R; Barbosa, D B; Henriques, M
2013-04-01
The aim of this study was to assess the effect of different silver nanoparticles (SN) concentrations on the matrix composition and structure of Candida albicans and Candida glabrata biofilms. Candida biofilms were developed in 6-well microtiter plates during 48 h. After, these biofilms were exposed to 13.5 or 54 μg SN ml(-1) for 24 h. Then, extracellular matrices were extracted from biofilms and analysed chemically in terms of proteins, carbohydrates and DNA. To investigate the biofilm structure, scanning electron microscopy (SEM) and epifluorescence microscopy were used. SN interfered with the matrix composition of Candida biofilms tested in terms of protein, carbohydrate and DNA, except for the protein content of C. albicans biofilm. By SEM, Candida biofilms treated with SN revealed structural differences, when compared with the control groups. Further, SN showed a trend of agglomeration within the biofilms. Epifluorescence microscopy images suggest that SN induced damage on cell walls of the Candida isolates tested. In general, irrespective of concentration, SN affected the matrix composition and structure of Candida biofilms and these findings may be related to the mechanisms of biocide action of SN. This study reveals new insights about the behaviour of SN when in contact with Candida biofilms. SN may contribute to the development of therapies to prevent or control Candida infections. © 2012 The Society for Applied Microbiology.
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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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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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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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Troskie, Anscha Mari; Rautenbach, Marina; Delattin, Nicolas; Vosloo, Johan Arnold; Dathe, Margitta; Cammue, Bruno P A; Thevissen, Karin
2014-07-01
Tyrocidines are cationic cyclodecapeptides from Bacillus aneurinolyticus that are characterized by potent antibacterial and antimalarial activities. In this study, we show that various tyrocidines have significant activity against planktonic Candida albicans in the low-micromolar range. These tyrocidines also prevented C. albicans biofilm formation in vitro. Studies with the membrane-impermeable dye propidium iodide showed that the tyrocidines disrupt the membrane integrity of mature C. albicans biofilm cells. This membrane activity correlated with the permeabilization and rapid lysis of model fungal membranes containing phosphatidylcholine and ergosterol (70:30 ratio) induced by the tyrocidines. The tyrocidines exhibited pronounced synergistic biofilm-eradicating activity in combination with two key antifungal drugs, amphotericin B and caspofungin. Using a Caenorhabditis elegans infection model, we found that tyrocidine A potentiated the activity of caspofungin. Therefore, tyrocidines are promising candidates for further research as antifungal drugs and as agents for combinatorial treatment. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
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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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Rodrigues, Célia F; Gonçalves, Bruna; Rodrigues, Maria Elisa; Silva, Sónia; Azeredo, Joana; Henriques, Mariana
2017-08-01
Candida glabrata is one of most prevalent yeast in fungal infections, especially in immunocompromised patients. Its azole resistance results in a low therapeutic response, particularly when associated with biofilms. The main goal of this work was to study the effectiveness of voriconazole (Vcz) against C. glabrata biofilms oral pathologies, as esophageal or oropharyngeal candidiasis. Antifungal susceptibilities were determined in pre-formed 24-h-biofilms and ERG genes expression was determined by qRT-PCR. Protein quantification was performed using BCA ® Kit, carbohydrate was estimated according to the Dubois assay and β-1,3 glucans concentration were determined using Glucatell ® kit. Finally, ergosterol, Vcz, and fluconazole (Flu) concentrations within the biofilm matrices were determined by RP-HPLC. Results showed that C. glabrata biofilms were more susceptible to Vcz than to Flu and that ERG genes expression evidenced an overexpression of the three ERG genes in the presence of both azoles. The matrix content presented a remarked decrease in proteins and an increase in carbohydrates, namely β-1,3 glucans. Ergosterol was successfully detected and quantified in the biofilm matrices, with no differences in all the considered conditions. Vcz demonstrated better diffusion through the biofilms and better cell penetration capacities, than Flu, indicating that the structure of the drug molecule fully influences its dissemination through the biofilm matrices. This work showed that Vcz is notably more effective than Flu for the treatment of resistant C. glabrata oral biofilms, which demonstrates a clinical relevance in its future use for the treatment of oropharyngeal/esophageal candidiasis caused by this species.
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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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Franks, A.; Egan, S.; Holmström, C.; James, S.; Lappin-Scott, H.; Kjelleberg, S.
2006-01-01
The marine epiphytic bacterium Pseudoalteromonas tunicata produces a range of extracellular secondary metabolites that inhibit an array of common fouling organisms, including fungi. In this study, we test the hypothesis that the ability to inhibit fungi provides P. tunicata with an advantage during colonization of a surface. Studies on a transposon-generated antifungal-deficient mutant of P. tunicata, FM3, indicated that a long-chain fatty acid-coenzyme A ligase is involved in the production of a broad-range antifungal compound by P. tunicata. Flow cell experiments demonstrated that production of an antifungal compound provided P. tunicata with a competitive advantage against a marine yeast isolate during surface colonization. This compound enabled P. tunicata to disrupt an already established fungal biofilm by decreasing the number of yeast cells attached to the surface by 66% ± 9%. For in vivo experiments, the wild-type and FM3 strains of P. tunicata were used to inoculate the surface of the green alga Ulva australis. Double-gradient denaturing gradient gel electrophoresis analysis revealed that after 48 h, the wild-type P. tunicata had outcompeted the surface-associated fungal community, whereas the antifungal-deficient mutant had no effect on the fungal community. Our data suggest that P. tunicata is an effective competitor against fungal surface communities in the marine environment. PMID:16957232
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Indoor microbiota in severely moisture damaged homes and the impact of interventions.
Jayaprakash, Balamuralikrishna; Adams, Rachel I; Kirjavainen, Pirkka; Karvonen, Anne; Vepsäläinen, Asko; Valkonen, Maria; Järvi, Kati; Sulyok, Michael; Pekkanen, Juha; Hyvärinen, Anne; Täubel, Martin
2017-10-13
The limited understanding of microbial characteristics in moisture-damaged buildings impedes efforts to clarify which adverse health effects in the occupants are associated with the damage and to develop effective building intervention strategies. The objectives of this current study were (i) to characterize fungal and bacterial microbiota in house dust of severely moisture-damaged residences, (ii) to identify microbial taxa associated with moisture damage renovations, and (iii) to test whether the associations between the identified taxa and moisture damage are replicable in another cohort of homes. We applied bacterial 16S rRNA gene and fungal ITS amplicon sequencing complemented with quantitative PCR and chemical-analytical approaches to samples of house dust, and also performed traditional cultivation of bacteria and fungi from building material samples. Active microbial growth on building materials had significant though small influence on the house dust bacterial and fungal communities. Moisture damage interventions-including actual renovation of damaged homes and cases where families moved to another home-had only a subtle effect on bacterial community structure, seen as shifts in abundance weighted bacterial profiles after intervention. While bacterial and fungal species richness were reduced in homes that were renovated, they were not reduced for families that moved houses. Using different discriminant analysis tools, we were able identify taxa that were significantly reduced in relative abundance during renovation of moisture damage. For bacteria, the majority of candidates belonged to different families within the Actinomycetales order. Results for fungi were overall less consistent. A replication study in approximately 400 homes highlighted some of the identified taxa, confirming associations with observations of moisture damage and mold. The present study is one of the first studies to analyze changes in microbiota due to moisture damage interventions
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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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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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Guo, Hao; Wang, Ziming; Du, Quanyin; Li, Pan; Wang, Zhigang; Wang, Aimin
2017-01-01
Bacterial biofilms on the surface of prostheses are becoming a rising concern in managing prosthetic joint infections. The inherent resistant features of biofilms render traditional antimicrobial therapy unproductive and revision surgery outcomes uncertain. This situation has prompted the exploration of novel antimicrobial strategies. The synergy of ultrasound microbubbles and vancomycin has been proposed as an efficient alternative for biofilm eradication. The purpose of this study was to evaluate the anti-biofilm effect of stimulated phase-shift acoustic nanodroplets (NDs) combined with vancomycin. We fabricated lipid phase-shift NDs with a core of liquid perfluoropentane. A new phase change mode for NDs incorporating an initial unfocused low-intensity pulsed ultrasound for 5 minutes and a subsequent incubation at 37°C into a 24-hour duration was developed. Methicillin-resistant Staphylococcus aureus (MRSA) biofilms were incubated with vancomycin and NDs under the hybrid stimulation. Biofilm morphology following treatment was determined using confocal laser scanning microscopy and scanning electron microscopy. Resazurin assay was used to quantify bactericidal efficacy against MRSA biofilm bacteria. NDs treated sequentially with ultrasound and heating at 37°C achieved gradual and substantial ND vaporization and cavitation in a successive process. NDs after stimulation were capable of generating stronger destruction on biofilm structure which was best characterized by residual circular arc margins and more dead bacteria. Furthermore, NDs combined with vancomycin contributed to significantly decreasing the metabolic activity of bacteria in MRSA biofilms ( P <0.05). Phase-shift acoustic NDs could exert a significant bactericidal effect against MRSA biofilms through a new stimulation mode. Acoustic NDs present advantages over microbubbles for biofilm damage. This anti-biofilm strategy could be used either alone or as an enhancer of traditional antibiotics in the
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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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Hover, Tal; Maya, Tal; Ron, Sapir; Sandovsky, Hani; Shadkchan, Yana; Kijner, Nitzan; Mitiagin, Yulia; Fichtman, Boris; Harel, Amnon; Shanks, Robert M Q; Bruna, Roberto E; García-Véscovi, Eleonora; Osherov, Nir
2016-05-01
We have found a remarkable capacity for the ubiquitous Gram-negative rod bacterium Serratia marcescens to migrate along and kill the mycelia of zygomycete molds. This migration was restricted to zygomycete molds and several basidiomycete species. No migration was seen on any molds of the phylum Ascomycota. S. marcescens migration did not require fungal viability or surrounding growth medium, as bacteria migrated along aerial hyphae as well.S. marcescens did not exhibit growth tropism toward zygomycete mycelium. Bacterial migration along hyphae proceeded only when the hyphae grew into the bacterial colony. S. marcescens cells initially migrated along the hyphae, forming attached microcolonies that grew and coalesced to generate a biofilm that covered and killed the mycelium. Flagellum-defective strains of S. marcescens were able to migrate along zygomycete hyphae, although they were significantly slower than the wild-type strain and were delayed in fungal killing. Bacterial attachment to the mycelium does not necessitate type 1 fimbrial adhesion, since mutants defective in this adhesin migrated equally well as or faster than the wild-type strain. Killing does not depend on the secretion of S. marcescens chitinases, as mutants in which all three chitinase genes were deleted retained wild-type killing abilities. A better understanding of the mechanisms by which S. marcescens binds to, spreads on, and kills fungal hyphae might serve as an excellent model system for such interactions in general; fungal killing could be employed in agricultural fungal biocontrol. Copyright © 2016, American Society for Microbiology. All Rights Reserved.
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Denture-associated biofilm infection in three-dimensional oral mucosal tissue models.
Morse, Daniel J; Wilson, Melanie J; Wei, Xiaoqing; Lewis, Michael A O; Bradshaw, David J; Murdoch, Craig; Williams, David W
2018-03-01
In vitro analyses of virulence, pathogenicity and associated host cell responses are important components in the study of biofilm infections. The Candida-related infection, denture-associated oral candidosis, affects up to 60 % of denture wearers and manifests as inflammation of palatal tissues contacting the denture-fitting surface. Commercially available three-dimensional tissue models can be used to study infection, but their use is limited for many academic research institutions, primarily because of the substantial purchase costs. The aim of this study was to develop and evaluate the use of in vitro tissue models to assess infections by biofilms on acrylic surfaces through tissue damage and Candida albicans virulence gene expression. In vitro models were compared against commercially available tissue equivalents (keratinocyte-only, SkinEthic; full-thickness, MatTek Corporation). An in vitro keratinocyte-only tissue was produced using a cancer-derived cell line, TR146, and a full-thickness model incorporating primary fibroblasts and immortalised normal oral keratinocytes was also generated. The in vitro full-thickness tissues incorporated keratinocytes and fibroblasts, and have potential for future further development and analysis. Following polymicrobial infection with biofilms on acrylic surfaces, both in-house developed models were shown to provide equivalent results to the SkinEthic and MatTek models in terms of tissue damage: a significant (P<0.05) increase in LDH activity for mixed species biofilms compared to uninfected control, and no significant difference (P>0.05) in the expression of most C. albicans virulence genes when comparing tissue models of the same type. Our results confirm the feasibility and suitability of using these alternative in vitro tissue models for such analyses.
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Wu, Yachuan; Quan, Xiangchun; Si, Xiurong; Wang, Xinrui
2016-06-01
Detrimental biofilms have become a great concern in many areas due to their strong resistance and insensitivity to traditional antimicrobial agents. Norspermidine is a potent small molecule for biofilm dispersal. In this study, silver ion, a conventional inorganic biocide, was combined with norspermidine and used for control and removal of multi-species biofilms formed by a mixed culture from wastewater treatment systems. Results showed that silver ion (0.01-1 mg/L) treatment alone failed to remove the existing wastewater biofilms. Norspermidine at the concentrations of 500-1000 μM was capable to disrupt and disperse the existing biofilms with a biofilm reduction of 21-34 % after 24-h exposure. The combined treatment with norspermidine (500 μM) and silver ion (0.01 mg/L) increased biofilm reduction to 48 % (24-h exposure). The combined treatment also enhanced biofilm disinfection ratio (82 %, 2-h exposure) by 2.0- and 2.6-folds compared to norspermidine (27 %) or silver ion (23 %) treatment alone, respectively. Confocal laser scanning microscopic (CLSM) observations found that norspermidine could disrupt biofilm matrix and promote biofilm dispersal via breaking down exopolysaccharides. The combined treatment increased the reduction in biofilm cell density and viability, possibly due to the damage of biofilm matrix, enhanced silver ion diffusion in biofilms, and increased biofilm sensitivity. These findings indicate that the combination of a small molecule norspermidine with a traditional biocide silver ion presents a novel strategy to remove and kill biofilms, which have a potential application in addressing wastewater biofilm-related issues.
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Influence of local climate and climate change on aeroterrestrial phototrophic biofilms.
Gladis-Schmacka, Franziska; Glatzel, Stephan; Karsten, Ulf; Böttcher, Heidrun; Schumann, Rhena
2014-01-01
Aeroterrestrial phototrophic biofilms colonize natural and man-made surfaces and may damage the material they settle on. The occurrence of biofilms varies between regions with different climatic conditions. The aim of this study was to evaluate the influence of meteorological factors on the growth of aeroterrestrial phototrophs. Phototrophic biomass was recorded on roof tiles at six sites within Germany five times over a period of five years and compared to climatic parameters from neighboring weather stations. All correlating meteorological factors influenced water availability on the surface of the roof tiles. The results indicate that the frequency of rainy days and not the mean precipitation per season is more important for biofilm proliferation. It is also inferred that the macroclimate is more important than the microclimate. In conclusion, changed (regional) climatic conditions may determine where in central Europe global change will promote or inhibit phototrophic growth in the future.
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Evaluation of fungal growth on cellulose-containing and inorganic ceiling tile.
Karunasena, E; Markham, N; Brasel, T; Cooley, J D; Straus, D C
2001-01-01
Buildings with poor indoor air quality (IAQ) frequently have many areas with surface fungal contamination. Studies have demonstrated that certain fungal genera (e.g., Cladosporium, Penicillium, and Stachybotrys) are able to grow on building materials such as wallpaper, drywall, and ceiling tiles, particularly after water damage has occurred. Due to the increasing awareness of sick building syndrome (SBS), it has become essential to identify building materials that prevent the interior growth of fungi. The objective of this study was to identify building materials that would not support the growth of certain fungal genera, regardless of whether an external food source was made available. The growth of three fungal genera (Cladosporium, Penicillium, and Stachybotrys) was evaluated on cellulose-containing ceiling tile (CCT) and inorganic ceiling tile (ICT). Both types of ceiling tile were exposed to environmental conditions which can occur inside a building. Our results show that ICT did not support the growth of these three fungal genera while CCT did. Our data demonstrate that ICT could serve as an ideal replacement for CCT.
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Biofilm Producing Salmonella Typhi: Chronic Colonization and Development of Gallbladder Cancer
Cavallo, Ilaria; Pontone, Martina; Toma, Luigi; Ensoli, Fabrizio
2017-01-01
Salmonella enterica subspecies enterica serovar Typhi is the aetiological agent of typhoid or enteric fever. In a subset of individuals, S. Typhi colonizes the gallbladder causing an asymptomatic chronic infection. Nonetheless, these asymptomatic carriers provide a reservoir for further spreading of the disease. Epidemiological studies performed in regions where S. Typhi is endemic, revealed that the majority of chronically infected carriers also harbour gallstones, which in turn, have been indicated as a primary predisposing factor for the onset of gallbladder cancer (GC). It is now well recognised, that S. Typhi produces a typhoid toxin with a carcinogenic potential, that induces DNA damage and cell cycle alterations in intoxicated cells. In addition, biofilm production by S. Typhi may represent a key factor for the promotion of a persistent infection in the gallbladder, thus sustaining a chronic local inflammatory response and exposing the epithelium to repeated damage caused by carcinogenic toxins. This review aims to highlight the putative connection between the chronic colonization by highly pathogenic strains of S. Typhi capable of combining biofilm and toxin production and the onset of GC. Considering the high risk of GC associated with the asymptomatic carrier status, the rapid identification and profiling of biofilm production by S. Typhi strains would be key for effective therapeutic management and cancer prevention. PMID:28858232
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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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NASA Astrophysics Data System (ADS)
Xu, Zimu; Shen, Jie; Cheng, Cheng; Hu, Shuheng; Lan, Yan; Chu, Paul K.
2017-03-01
The antimicrobial effects and associated mechanism of inactivation of Staphylococcus aureus (S. aureus) NCTC-8325 biofilms induced by a He/O2 atmospheric-pressure plasma jet (APPJ) are investigated in vitro. According to CFU (colony forming units) counting and the resazurin-based assay, the 10 min He/O2 (0.5%) APPJ treatment produces the optimal inactivation efficacy (>5 log10 ml-1) against the S. aureus biofilm and 5% of the bacteria enter a viable but non-culturable (VBNC) state. Meanwhile, 94% of the bacteria suffer from membrane damage according to SYTO 9/PI counterstaining. Scanning electron microscopy (SEM) reveals that plasma exposure erodes the extracellular polymeric substances (EPS) and then the cellular structure. The H2DCFDA-stained biofilms show larger concentrations of intracellular reactive oxygen species (ROS) in membrane-intact bacteria with increasing plasma dose. The admixture of oxygen in the working gas highly contributes to the deactivation efficacy of the APPJ against S. aureus and the plasma-induced endogenous ROS may work together with the discharge-generated ROS to continuously damage the bacterial membrane structure leading to deactivation of the biofilm microbes.
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Zhou, Hao; Wang, Guochen; Wu, Minghuo; Xu, Weiping; Zhang, Xuwang; Liu, Lifen
2018-06-05
A moving bed biofilm reactor (MBBR) effectively removes pollutants and even runs under extreme conditions. However, the pH shock resistance of a biofilm in MBBRs has been rarely reported. In this study, simulated phenol wastewater with acidic shock (pH 7.5-3.0) was used. In the pH shock phase, the phenol and COD removal efficiencies initially decreased and gradually increased to more than 90%. Microscopic studies showed that the superficial biofilm was mainly composed of fungi (yeasts) in the acidic pH shock phase. The microbial community composition in the acidic pH shock phase was significantly different from those in other phases. Firmicutes and Ascomycota were the dominant bacterial and fungal phyla in this stage, respectively. 16S rRNA gene-based functional annotation indicated that functional profiles related to aromatic compound degradation existed in all of the stages. Therefore, MBBRs show potential for the treatment of phenolic wastewater exposed to pH shock. Copyright © 2018 Elsevier B.V. All rights reserved.
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Polizzi, Viviana; Adams, An; Malysheva, Svetlana V; De Saeger, Sarah; Van Peteghem, Carlos; Moretti, Antonio; Picco, Anna Maria; De Kimpe, Norbert
2012-09-01
Microbial volatile organic compounds (MVOCs) were collected in water-damaged buildings to evaluate their use as possible indicators of indoor fungal growth. Fungal species isolated from contaminated buildings were screened for MVOC production on malt extract agar by means of headspace solid-phase microextraction followed by gas chromatography-mass spectrometry (GC-MS) analysis. Some sesquiterpenes, specifically derived from fungal growth, were detected in the sampled environments and the corresponding fungal producers were identified. Statistical analysis of the detected MVOC profiles allowed the identification of species-specific MVOCs or MVOC patterns for Aspergillus versicolor group, Aspergillus ustus, and Eurotium amstelodami. In addition, Chaetomium spp. and Epicoccum spp. were clearly differentiated by their volatile production from a group of 76 fungal strains belonging to different genera. These results are useful in the chemotaxonomic discrimination of fungal species, in aid to the classical morphological and molecular identification techniques. Copyright © 2012 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.
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2011-01-01
established on microbiologically naıve tissues (such as in endocarditis or cystic fibrosis). Whether on damaged heart valves or poorly functioning respiratory...time. Although wound infections represent a spectrum of bacterial phenotypes, involving bacteria in both the plank- tonic and biofilm phases, we use...our model to study differ- ences in planktonic- and biofilm-dominant infections , which are classically associated with acute and chronic wound
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Carrillo, Daniel; Cruz, Luisa F.; Kendra, Paul E.; Narvaez, Teresa I.; Montgomery, Wayne S.; Monterroso, Armando; De Grave, Charlotte; Cooperband, Miriam F.
2016-01-01
Members of a complex of cryptic species, that correspond morphologically to the ambrosia beetle Euwallacea fornicatus (Eichhoff) (Coleoptera: Curculionidae: Scolytinae), were recently found attacking avocado (Persea americana Mill.) in Israel and California. In early 2016, an outbreak of another member of this species complex was detected infesting approximately 1500 avocado trees in an avocado orchard at Homestead, Florida. An area-wide survey was conducted in commercial avocado groves of Miami-Dade County, Florida to determine the distribution and abundance of E. nr. fornicatus, to identify different populations of E. nr. fornicatus and their fungal associates, and to assess the extent of damage to avocado trees. Ewallacea nr. fornicatus were captured in 31 of the 33 sampled sites. A sample of 35 beetles from six different locations was identified as E. nr. fornicatus sp. #2, which is genetically distinct from the species causing damage in California and Israel. Eleven fungal associates were identified: an unknown Fusarium sp., AF-8, AF-6, Graphium euwallaceae, Acremonium sp. Acremonium morum, Acremonium masseei, Elaphocordyceps sp. and three yeast species. The unknown Fusarium isolates were the most abundant and frequently found fungus species associated with adult beetles and lesions surrounding the beetle galleries. In addition to fungal associates, three bacteria species were found associated with adult E. nr. fornicatus. Visual inspections detected significant damage in only two orchards. A large number of beetles were captured in locations with no apparent damage on the avocado trees suggesting that E. nr. fornicatus are associated with other host(s) outside the groves or with dead trees or branches inside the groves. More research is needed to determine the potential threat E. nr. fornicatus and its fungal associates pose to the avocado industry and agricultural and natural ecosystems in Florida. PMID:27754408
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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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[Damage of modern building materials by microscopic fungi].
Chuenko, A I; Karpenko, Iu V
2011-01-01
Resistance of three materials, produced on the basis of concrete compounds to the action of microscopic fungi, isolated from damaged living buildings, has been first investigated. It has been shown that samples of froth-block and thermoeffective block had low fungal resistance, in contrast to samples of cellular polystyrene concrete, which were resistant to fungal action, that can be associated with peculiarities of their component composition.
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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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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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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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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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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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Effects of patchouli and cinnamon essential oils on biofilm and hyphae formation by Candida species.
Farisa Banu, S; Rubini, D; Shanmugavelan, P; Murugan, R; Gowrishankar, S; Karutha Pandian, S; Nithyanand, P
2018-06-01
The prevalence and fatality rates with biofilm-associated candidal infections have remained a challenge to the medical fraternity despite major advances in the field of antifungal therapy. Traditionally, essential oils (EOs) from the aromatic plants have been found to be excellent therapeutic agents to treat fungal ailments. The present study explores the antivirulent and antibiofilm effects of under explored leaf EOs of Indian patchouli EO extracted from Pogostemon heyneanus (PH), Indian cassia from Cinnamomum tamala (CT) and camphor EO from C. camphora (CC) against Candida species. The EOs were investigated for its efficacy to disrupt the young and preformed Candida spp. biofilms and to inhibit the yeast to hyphal transition, a hallmark virulent trait of C. albicans. The ability of these EOs to inhibit metabolically active cells was assessed through XTT assay. Of these three EOs, CT EO showed enhanced biofilm inhibition than others and hence it was further selected to study its biomass inhibition potential and exopolysaccharide layer disruption ability. The CT EO reduced the biomass of the preformed biofilms of all three Candida strains, which was supported by confocal microscopy. It also disrupted the exopolysaccharide layer of the Candida strains as shown by scanning electron microscopy. The present findings validate the effectiveness of EOs against the virulence of Candida spp. and emphasize the pharmaceutical potential of several native but yet unexplored wild aromatic plants in the prospect of therapeutic application. Copyright © 2018 Elsevier Masson SAS. All rights reserved.
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Cherifi, Tamazight; Jacques, Mario; Quessy, Sylvain; Fravalo, Philippe
2017-01-01
Biofilm formation by the pathogen Listeria monocytogenes is a major concern in food industries. The aim of this work was to elucidate the effect of nutrient limitation on both biofilm architecture and on the viability of the bacteria in microfluidic growth conditions. Biofilm formation by two L. monocytogenes strains was performed in a rich medium (BHI) and in a 10-fold diluted BHI (BHI/10) at 30°C for 24 h by using both static conditions and the microfluidic system Bioflux. In dynamic conditions, biofilms grown in rich and poor medium showed significant differences as well in structure and in the resulting biovolume. In BHI/10, biofilm was organized in a knitted network where cells formed long chains, whereas in the rich medium, the observed structure was homogeneous cellular multilayers. Biofilm biovolume production in BHI/10 was significantly higher than in BHI in these dynamic conditions. Interestingly, biovolume of dead cells in biofilms formed under limited nutrient conditions (BHI/10) was significantly higher than in biofilms formed in the BHI medium. In the other hand, in static conditions, biofilm is organized in a multilayer cells and dispersed cells in a rich medium BHI and poor medium BHI/10 respectively. There was significantly more biomass in the rich medium compared to BHI/10 but no difference was noted in the dead/damaged subpopulation showing how L. monocytogenes biofilm could be affected by the growth conditions. This work demonstrated that nutrient concentration affects biofilm structure and the proportion of dead cells in biofilms under microfluidic condition. Our study also showed that limited nutrients play an important role in the structural stability of L. monocytogenes biofilm by enhancing cell death and liberating extracellular DNA.
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Cherifi, Tamazight; Jacques, Mario; Quessy, Sylvain; Fravalo, Philippe
2017-01-01
Biofilm formation by the pathogen Listeria monocytogenes is a major concern in food industries. The aim of this work was to elucidate the effect of nutrient limitation on both biofilm architecture and on the viability of the bacteria in microfluidic growth conditions. Biofilm formation by two L. monocytogenes strains was performed in a rich medium (BHI) and in a 10-fold diluted BHI (BHI/10) at 30°C for 24 h by using both static conditions and the microfluidic system Bioflux. In dynamic conditions, biofilms grown in rich and poor medium showed significant differences as well in structure and in the resulting biovolume. In BHI/10, biofilm was organized in a knitted network where cells formed long chains, whereas in the rich medium, the observed structure was homogeneous cellular multilayers. Biofilm biovolume production in BHI/10 was significantly higher than in BHI in these dynamic conditions. Interestingly, biovolume of dead cells in biofilms formed under limited nutrient conditions (BHI/10) was significantly higher than in biofilms formed in the BHI medium. In the other hand, in static conditions, biofilm is organized in a multilayer cells and dispersed cells in a rich medium BHI and poor medium BHI/10 respectively. There was significantly more biomass in the rich medium compared to BHI/10 but no difference was noted in the dead/damaged subpopulation showing how L. monocytogenes biofilm could be affected by the growth conditions. This work demonstrated that nutrient concentration affects biofilm structure and the proportion of dead cells in biofilms under microfluidic condition. Our study also showed that limited nutrients play an important role in the structural stability of L. monocytogenes biofilm by enhancing cell death and liberating extracellular DNA. PMID:28567031
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Fungal and Bacterial Infection Mitigation with Antibiotic and Antifungal Loaded Biopolymer Sponges
NASA Astrophysics Data System (ADS)
Parker, Ashley Cox
Musculoskeletal injuries are some of the most prevalent injuries in both civilian and military populations and their infections can be difficult to treat, often resulting in multiple surgeries and increased costs. In both previous and recent military operations, extremity injuries have been the most common battlefield injuries and many involve complex, open fractures. These extremity injuries are especially susceptible to multiple pathogenic, and sometimes drug resistant, bacteria and fungi. Fungal infections have recently become increasingly problematic in both military and civilian populations and have significantly higher amputation rates than those from bacterial infections. Many of these bacterial and fungal strains adhere to tissue and implanted orthopaedic hardware within wounds, forming biofilms. These problematic, often polymicrobial, infections threaten the health of the patient, but the risk also exists of spreading within hospitals to become prominent resistant infections. Local antimicrobial delivery releases high levels of antimicrobials directly to injured wound tissue, overcoming sub-bactericidal or subfungicidal antimicrobial levels present in the avascular wound zones. This research will determine the ability of modified chitosan sponges, buffered with sodium acetate or blended with polyethylene glycol (PEG), to act as short term adjunctive therapies to initial surgical treatment for delivering both antibiotics and/or antifungals for early abatement of infection. The objective of this work was to evaluate both types of modified sponges for in vitro and in vivo material characteristics and device functionality. In vitro analysis demonstrated both the buffered and PEG modified chitosan sponges exhibited increased degradation and functional cytocompatibility. The chitosan/PEG sponges were able to be loaded with hydrophobic antifungals and the sponges released in vitro biologically active concentrations, alone or in combination with the antibiotic
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Holbrook, Selina Y L; Garzan, Atefeh; Dennis, Emily K; Shrestha, Sanjib K; Garneau-Tsodikova, Sylvie
2017-10-20
As the number of hospitalized and immunocompromised patients continues to rise, invasive fungal infections, such as invasive candidiasis and aspergillosis, threaten the life of millions of patients every year. The azole antifungals are currently the most prescribed drugs clinically that display broad-spectrum antifungal activity and excellent oral bioavailability. Yet, the azole antifungals have their own limitations and are unable to meet the challenges associated with increasing fungal infections and the accompanied development of resistance against azoles. Exploring combination therapy that involves the current azoles and another drug has been shown to be a promising strategy. Haloperidol and its derivative, bromperidol, were originally discovered as antipsychotics. Herein, we synthesize and report a series of bromperidol derivatives and their synergistic antifungal interactions in combination with a variety of current azole antifungals against a wide panel of fungal pathogens. We further select two representative combinations and confirm the antifungal synergy by performing time-kill assays. Furthermore, we evaluate the ability of selected combinations to destroy fungal biofilm. Finally, we perform mammalian cytotoxicity assays with the representative combinations against three mammalian cell lines. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
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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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Wang, Longfei; Li, Yi; Wang, Li; Zhang, Huanjun; Zhu, Mengjie; Zhang, Peisheng; Zhu, Xiaoxiao
2018-04-01
The occurrence and transportation of antibiotics in biofilms from natural and engineered sources have attracted increasing interests. Nevertheless, the effects of extracellular polymeric substances (EPS) on the responses of biofilms to the exposure to antibiotics are not clear. In this study, the effects of EPS on the sorption and biological responses to one representative antibiotic, sulfamethizole (STZ), in model biofilms were investigated. Proteins dominated the interactions between the EPS and the STZ and the EPS from a moving bed biofilm reactor exhibited the strongest interaction with the STZ. The EPS served as important reservoirs for the STZ and the tested biofilms all showed reduced sorption capacities for the STZ after the EPS were extracted. The respiratory rates and typical enzymatic activities were reduced after the EPS were extracted. High-throughput 16S rRNA gene sequencing results confirmed that the bacterial community in the biofilm without the EPS was more vulnerable to antibiotic shock as indicated by the community diversity and richness indices. A greater increase in the abundance of susceptible species was observed in the natural biofilm. The results comprehensively suggested that the EPS played important role in biosorption of STZ and alleviated the direct damage of the antibiotic to the cells; in addition the extent of the bacterial community response was associated with the origins of the biofilms. Our study provided details on the responses of multi-species biofilms to the exposure to an antibiotic and highlighted the role of the EPS in interacting with the antibiotic, thereby providing a deeper understanding of the bioremediation of antibiotics in real-life natural and engineered biofilm systems. Copyright © 2017 Elsevier Ltd. 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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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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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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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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Vieira, Edson Rodrigues; Xisto, Mariana Ingrid Dutra da Silva; Pele, Milagre Américo; Alviano, Daniela Sales; Alviano, Celuta Sales; Barreto-Bergter, Eliana; de Campos-Takaki, Galba Maria
2018-06-01
Monohexosylceramides (CMHs) are highly conserved fungal glycosphingolipids playing a role in several cellular processes such as growth, differentiation and morphological transition. In this study, we report the isolation, purification and chemical characterization of CMHs from Rhizopus stolonifer and R. microspores . Using positive ion mode ESI-MS, two major ion species were observed at m / z 750 and m / z 766, respectively. Both ion species consisted of a glucose/galactose residue attached to a ceramide moiety containing 9-methyl-4,8-sphingadienine with an amidic linkage to a hydroxylated C16:0 fatty acid. The antimicrobial activity of CMH was evaluated against Gram positive and Gram negative bacteria using the agar diffusion assay. CMH from both Rhizopus species inhibited the growth of Bacillus terrae , Micrococcus luteus ( M. luteus ) and Pseudomonas stutzeri ( P. stutzeri ) with a MIC 50 of 6.25, 6.25 and 3.13 mg/mL, respectively. The bactericidal effect was detected only for M. luteus and P. stutzeri , with MBC values of 25 and 6.25 mg/mL, respectively. Furthermore, the action of CMH on the biofilm produced by methicillin-resistant Staphylococcus aureus (MRSA) was analyzed using 12.5 and 25 mg/mL of CMH from R. microsporus . Total biofilm biomass, biofilm matrix and viability of the cells that form the biofilm structure were evaluated. CMH from R. microsporus was able to inhibit the MRSA biofilm formation in all parameters tested.
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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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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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Binnenkade, Lucas; Teichmann, Laura; Thormann, Kai M
2014-09-01
Prophages are ubiquitous elements within bacterial chromosomes and affect host physiology and ecology in multiple ways. We have previously demonstrated that phage-induced lysis is required for extracellular DNA (eDNA) release and normal biofilm formation in Shewanella oneidensis MR-1. Here, we investigated the regulatory mechanisms of prophage λSo spatiotemporal induction in biofilms. To this end, we used a functional fluorescence fusion to monitor λSo activation in various mutant backgrounds and in response to different physiological conditions. λSo induction occurred mainly in a subpopulation of filamentous cells in a strictly RecA-dependent manner, implicating oxidative stress-induced DNA damage as the major trigger. Accordingly, mutants affected in the oxidative stress response (ΔoxyR) or iron homeostasis (Δfur) displayed drastically increased levels of phage induction and abnormal biofilm formation, while planktonic cells were not or only marginally affected. To further investigate the role of oxidative stress, we performed a mutant screen and identified two independent amino acid substitutions in OxyR (T104N and L197P) that suppress induction of λSo by hydrogen peroxide (H2O2). However, λSo induction was not suppressed in biofilms formed by both mutants, suggesting a minor role of intracellular H2O2 in this process. In contrast, addition of iron to biofilms strongly enhanced λSo induction and eDNA release, while both processes were significantly suppressed at low iron levels, strongly indicating that iron is the limiting factor. We conclude that uptake of iron during biofilm formation triggers λSo-mediated lysis of a subpopulation of cells, likely by an increase in iron-mediated DNA damage sensed by RecA. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
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Gogoi-Tiwari, Jully; Williams, Vincent; Waryah, Charlene Babra; Costantino, Paul; Al-Salami, Hani; Mathavan, Sangeetha; Wells, Kelsi; Tiwari, Harish Kumar; Hegde, Nagendra; Isloor, Shrikrishna; Al-Sallami, Hesham; Mukkur, Trilochan
2017-01-01
Biofilm formation by Staphylococcus aureus is an important virulence attribute because of its potential to induce persistent antibiotic resistance, retard phagocytosis and either attenuate or promote inflammation, depending upon the disease syndrome, in vivo. This study was undertaken to evaluate the potential significance of strength of biofilm formation by clinical bovine mastitis-associated S. aureus in mammary tissue damage by using a mouse mastitis model. Two S. aureus strains of the same capsular phenotype with different biofilm forming strengths were used to non-invasively infect mammary glands of lactating mice. Biofilm forming potential of these strains were determined by tissue culture plate method, ica typing and virulence gene profile per detection by PCR. Delivery of the infectious dose of S. aureus was directly through the teat lactiferous duct without invasive scraping of the teat surface. Both bacteriological and histological methods were used for analysis of mammary gland pathology of mice post-infection. Histopathological analysis of the infected mammary glands revealed that mice inoculated with the strong biofilm forming S. aureus strain produced marked acute mastitic lesions, showing profuse infiltration predominantly with neutrophils, with evidence of necrosis in the affected mammary glands. In contrast, the damage was significantly less severe in mammary glands of mice infected with the weak biofilm-forming S. aureus strain. Although both IL-1β and TNF-α inflammatory biomarkers were produced in infected mice, level of TNF-α produced was significantly higher (p<0.05) in mice inoculated with strong biofilm forming S. aureus than the weak biofilm forming strain. This finding suggests an important role of TNF-α in mammary gland pathology post-infection with strong biofilm-forming S. aureus in the acute mouse mastitis model, and offers an opportunity for the development of novel strategies for reduction of mammary tissue damage, with or without
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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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Lockhart, Joey S; Buret, Andre G; Ceri, Howard; Storey, Douglas G; Anderson, Stefanie J; Morck, Douglas W
2017-10-01
Biofilms composed of anaerobic bacteria can result in persistent infections and chronic inflammation. Host immune cells have difficulties clearing biofilm-related infections and this can result in tissue damage. Neutrophils are a vital component of the innate immune system and help clear biofilms. The comparative neutrophilic response to biofilms versus planktonic bacteria remains incompletely understood, particularly in the context of mixed infections. The objective of this study was to generate mixed species anaerobic bacterial biofilms composed of two opportunistic pathogens, Fusobacterium necrophorum and Porphyromonas levii, and evaluate neutrophil responses to extracellular fractions from both biofilms and planktonic cell co-cultures of the same bacteria. Purified bovine neutrophils exposed to culture supernatants from mixed species planktonic bacteria showed elevated oxidative activity compared to neutrophils exposed to biofilms composed of the same bacteria. Bacterial lipopolysaccharide plays a significant role in the stimulation of neutrophils; biofilms produced substantially more lipopolysaccharide than planktonic bacteria under these experimental conditions. Removal of lipopolysaccharide significantly reduced neutrophil oxidative response to culture supernatants of planktonic bacteria. Oxidative responses to LPS-removed biofilm supernatants and LPS-removed planktonic cell supernatants were similar. The limited neutrophil response to biofilm bacteria observed in this study supports the reduced ability of the innate immune system to eradicate biofilm-associated infections. Lipopolysaccharide is likely important in neutrophil response; however, the presence of other extracellular, immune modifying molecules in the bacterial media also appears to be important in altering neutrophil function. Copyright © 2017 Elsevier Ltd. All rights reserved.
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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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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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He, Jinzhi; Kim, Dongyeop; Zhou, Xuedong; Ahn, Sang-Joon; Burne, Robert A.; Richards, Vincent P.; Koo, Hyun
2017-01-01
Early childhood caries (ECC), which can lead to rampant tooth-decay that is painful and costly to treat, is one of the most prevalent infectious diseases affecting children worldwide. Previous studies support that interactions between Streptococcus mutans and Candida albicans are associated with the pathogenesis of ECC. The presence of Candida enhances S. mutans growth, fitness and accumulation within biofilms in vitro, although the molecular basis for these behaviors is undefined. Using an established co-cultivation biofilm model and RNA-Seq, we investigated how C. albicans influences the transcriptome of S. mutans. The presence of C. albicans dramatically altered gene expression in S. mutans in the dual-species biofilm, resulting in 393 genes differentially expressed, compared to mono-species biofilms of S. mutans. By Gene Ontology analysis, the majority of up-regulated genes were related to carbohydrate transport and metabolic/catabolic processes. KEGG pathway impact analysis showed elevated pyruvate and galactose metabolism, suggesting that co-cultivation with C. albicans influences carbohydrate utilization by S. mutans. Analysis of metabolites confirmed the increases in carbohydrate metabolism, with elevated amounts of formate in the culture medium of co-cultured biofilms. Moreover, co-cultivation with C. albicans altered transcription of S. mutans signal transduction (comC and ciaRH) genes associated with fitness and virulence. Interestingly, the expression of genes for mutacins (bacteriocins) and CRISPR were down-regulated. Collectively, the data provide a comprehensive insight into S. mutans transcriptomic changes induced by C. albicans, and offer novel insights into how bacterial–fungal interactions may enhance the severity of dental caries. PMID:28642749
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Davis, Michael J.; Eastman, Alison J.; Qiu, Yafeng; Gregorka, Brian; Kozel, Thomas R.; Osterholzer, John J.; Curtis, Jeffrey L.; Swanson, Joel A.; Olszewski, Michal A.
2015-01-01
Upon ingestion by macrophages, Cryptococcus neoformans (Cn) can survive and replicate intracellularly unless the macrophages become classically activated. The mechanism enabling intracellular replication is not fully understood; neither are the mechanisms which allow classical activation to counteract replication. Cn-induced lysosome damage was observed in infected murine bone marrow-derived macrophages, increased with time and required yeast viability. To demonstrate lysosome damage in the infected host, we developed a novel flow-cytometric method for measuring lysosome damage. Increased lysosome damage was found in Cn-containing lung cells compared to Cn–free cells. Among Cn-containing myeloid cells, recently recruited cells displayed lower damage than resident cells, consistent with the protective role of recruited macrophages. The magnitude of lysosome damage correlated with increased Cn replication. Experimental induction of lysosome damage increased Cn replication. Activation of macrophages with IFN-γ abolished macrophage lysosome damage and enabled increased killing of Cn. We conclude that induction of lysosome damage is an important Cn survival strategy and that classical activation of host macrophages counters replication by preventing damage. Thus, therapeutic strategies which decrease lysosomal damage, or increase resistance to such damage, could be valuable in treating cryptococcal infections. PMID:25637026
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Effect of diamond-like carbon thin film coated acrylic resin on candida albicans biofilm formation.
Queiroz, José Renato Cavalcanti; Fissmer, Sara Fernanda; Koga-Ito, Cristiane Yumi; Salvia, Ana C R D; Massi, Marcos; Sobrinho, Argermiro Soares da Silva; Júnior, Lafayette Nogueira
2013-08-01
The purpose of this study was to evaluate the effect of diamond-like carbon thin films doped and undoped with silver nanoparticles coating poly(methyl methacrylate) (PMMA) on Candida albicans biofilm formation. The control of biofilm formation is important to prevent oral diseases in denture users. Forty-five PMMA disks were obtained, finished, cleaned in an ultrasonic bath, and divided into three groups: Gc, no surface coating (control group); Gdlc, coated with diamond-like carbon film; and Gag, coated with diamond-like carbon film doped with silver nanoparticles. The films were deposited using a reactive magnetron sputtering system (physical vapor deposition process). The specimens were characterized by optical profilometry, atomic force microscopy, and Rutherford backscattering spectroscopy analyses that determined differences in chemical composition and morphological structure. Following sterilization of the specimens by γ-ray irradiation, C. albicans (ATCC 18804) biofilms were formed by immersion in 2 ml of Sabouraud dextrose broth inoculated with a standardized fungal suspension. After 24 hours, the number of colony forming units (cfu) per specimen was counted. Data concerning biofilm formation were analyzed using ANOVA and the Tukey test (p < 0.05). C. albicans biofilm formation was significantly influenced by the films (p < 0.00001), reducing the number of cfu, while not affecting the roughness parameters (p > 0.05). The Tukey test showed no significant difference between Gdlc and Gag. Films deposited were extremely thin (∼50 nm). The silver particles presented a diameter between 60 and 120 nm and regular distribution throughout the film surface (to Gag). Diamond-like carbon films, doped or undoped with silver nanoparticles, coating the base of PMMA-based dentures could be an alternative procedure for preventing candidosis in denture users. © 2013 by the American College of Prosthodontists.
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Nunes, Jorge Meneses; Bizerra, Fernando César; Ferreira, Renata Carmona e
2013-01-01
Rhodotorula species are emergent fungal pathogens capable of causing invasive infections, primarily fungemia. They are particularly problematic in immunosuppressed patients when using a central venous catheter. In this study, we evaluated the species distribution of 51 clinical and 8 environmental Rhodotorula species isolates using the ID32C system and internal transcribed spacer (ITS) sequencing. Antifungal susceptibility testing and biofilm formation capability using a crystal violet staining assay were performed. Using ITS sequencing as the gold standard, the clinical isolates were identified as follows: 44 R. mucilaginosa isolates, 2 R. glutinis isolates, 2 R. minuta isolates, 2 R. dairenensis isolates, and 1 Rhodosporidium fluviale isolate. The environmental isolates included 7 R. mucilaginosa isolates and 1 R. slooffiae isolate. Using the ID32C system, along with a nitrate assimilation test, only 90.3% of the isolates tested were correctly identified. In the biofilm formation assay, R. mucilaginosa and R. minuta exhibited greater biofilm formation ability compared to the other Rhodotorula species; the clinical isolates of R. mucilaginosa showed greater biofilm formation compared to the environmental isolates (P = 0.04). Amphotericin B showed good in vitro activity (MIC ≤ 1 μg/ml) against planktonic cells, whereas voriconazole and posaconazole showed poor activity (MIC50/MIC90, 2/4 μg/ml). Caspofungin and fluconazole MICs were consistently high for all isolates tested (≥64 μg/ml and ≥ 4 μg/ml, respectively). In this study, we emphasized the importance of molecular methods to correctly identify Rhodotorula species isolates and non-R. mucilaginosa species in particular. The antifungal susceptibility profile reinforces amphotericin B as the antifungal drug of choice for the treatment of Rhodotorula infections. To our knowledge, this is the first study evaluating putative differences in the ability of biofilm formation among different Rhodotorula species
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Nunes, Jorge Meneses; Bizerra, Fernando César; Ferreira, Renata Carmona E; Colombo, Arnaldo Lopes
2013-01-01
Rhodotorula species are emergent fungal pathogens capable of causing invasive infections, primarily fungemia. They are particularly problematic in immunosuppressed patients when using a central venous catheter. In this study, we evaluated the species distribution of 51 clinical and 8 environmental Rhodotorula species isolates using the ID32C system and internal transcribed spacer (ITS) sequencing. Antifungal susceptibility testing and biofilm formation capability using a crystal violet staining assay were performed. Using ITS sequencing as the gold standard, the clinical isolates were identified as follows: 44 R. mucilaginosa isolates, 2 R. glutinis isolates, 2 R. minuta isolates, 2 R. dairenensis isolates, and 1 Rhodosporidium fluviale isolate. The environmental isolates included 7 R. mucilaginosa isolates and 1 R. slooffiae isolate. Using the ID32C system, along with a nitrate assimilation test, only 90.3% of the isolates tested were correctly identified. In the biofilm formation assay, R. mucilaginosa and R. minuta exhibited greater biofilm formation ability compared to the other Rhodotorula species; the clinical isolates of R. mucilaginosa showed greater biofilm formation compared to the environmental isolates (P = 0.04). Amphotericin B showed good in vitro activity (MIC ≤ 1 μg/ml) against planktonic cells, whereas voriconazole and posaconazole showed poor activity (MIC(50)/MIC(90), 2/4 μg/ml). Caspofungin and fluconazole MICs were consistently high for all isolates tested (≥64 μg/ml and ≥ 4 μg/ml, respectively). In this study, we emphasized the importance of molecular methods to correctly identify Rhodotorula species isolates and non-R. mucilaginosa species in particular. The antifungal susceptibility profile reinforces amphotericin B as the antifungal drug of choice for the treatment of Rhodotorula infections. To our knowledge, this is the first study evaluating putative differences in the ability of biofilm formation among different Rhodotorula
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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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Dominguez, Eddie; Zarnowski, Robert; Sanchez, Hiram; Covelli, Antonio S; Westler, William M; Azadi, Parastoo; Nett, Jeniel; Mitchell, Aaron P; Andes, David R
2018-04-03
Candida biofilms resist the effects of available antifungal therapies. Prior studies with Candida albicans biofilms show that an extracellular matrix mannan-glucan complex (MGCx) contributes to antifungal sequestration, leading to drug resistance. Here we implement biochemical, pharmacological, and genetic approaches to explore a similar mechanism of resistance for the three most common clinically encountered non- albicans Candida species (NAC). Our findings reveal that each Candida species biofilm synthesizes a mannan-glucan complex and that the antifungal-protective function of this complex is conserved. Structural similarities extended primarily to the polysaccharide backbone (α-1,6-mannan and β-1,6-glucan). Surprisingly, biochemical analysis uncovered stark differences in the branching side chains of the MGCx among the species. Consistent with the structural analysis, similarities in the genetic control of MGCx production for each Candida species also appeared limited to the synthesis of the polysaccharide backbone. Each species appears to employ a unique subset of modification enzymes for MGCx synthesis, likely accounting for the observed side chain diversity. Our results argue for the conservation of matrix function among Candida spp. While biogenesis is preserved at the level of the mannan-glucan complex backbone, divergence emerges for construction of branching side chains. Thus, the MGCx backbone represents an ideal drug target for effective pan- Candida species biofilm therapy. IMPORTANCE Candida species, the most common fungal pathogens, frequently grow as a biofilm. These adherent communities tolerate extremely high concentrations of antifungal agents, due in large part, to a protective extracellular matrix. The present studies define the structural, functional, and genetic similarities and differences in the biofilm matrix from the four most common Candida species. Each species synthesizes an extracellular mannan-glucan complex (MGCx) which
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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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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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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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Brethauer, Simone; Robert Lawrence, Shahab; Michael Hans-Peter, Studer
2017-08-01
The aim of the present study was to investigate the combination of steam pretreatment and biological treatment with lignin degrading fungal strains in order to enable efficient bioprocessing of beech wood to ethanol. In a sequential process of steam and fungal pretreatment followed by enzymatic hydrolysis, Irpex lacteus almost doubled the glucose yield for mildly pretreated beech wood, but could not improve yields for more severely pretreated substrates. However, when simultaneous saccharification and fermentation is combined with in situ I. lacteus treatment, which is enabled by the application of a membrane aerated biofilm reactor, ethanol yields of optimally steam pretreated beech could be improved from 65 to 80%. Generally, in situ fungal treatment during bioprocessing of lignocellulose is an interesting method to harness the versatile abilities of white rot fungi. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.
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Hamad, Mawieh
2012-01-01
The complex nature of fungal pathogens, the intricate host-pathogen relationship and the health status of subjects in need of antifungal vaccination continue to hamper efforts to develop fungal vaccines for clinical use. That said, the rise of the universal vaccine concept is hoped to revive fungal vaccine research by expanding the pool of vaccine candidates worthy of clinical evaluation. It can do so through antigenic commonality-based screening for vaccine candidates from a wide range of pathogens and by reassessing the sizable collection of already available experimental and approved vaccines. Development of experimental vaccines protective against multiple fungal pathogens is evidence of the utility of this concept in fungal vaccine research. However, universal fungal vaccines are not without difficulties; for instance, development of vaccines with differential effectiveness is an issue that should be addressed. Additionally, rationalizing the development of universal fungal vaccines on health or economic basis could be contentious. Herein, universal fungal vaccines are discussed in terms of their potential usefulness and possible drawbacks. PMID:22922769
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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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Nagant, Carole; Pitts, Betsey; Stewart, Philip S; Feng, Yanshu; Savage, Paul B; Dehaye, Jean-Paul
2013-04-01
The formation of a Pseudomonas aeruginosa biofilm, a complex structure enclosing bacterial cells in an extracellular polymeric matrix, is responsible for persistent infections in cystic fibrosis patients leading to a high rate of morbidity and mortality. The protective environment created by the tridimensional structure reduces the susceptibility of the bacteria to conventional antibiotherapy. Cationic steroid antibiotics (CSA)-13, a nonpeptide mimic of antimicrobial peptides with antibacterial activity on planktonic cultures, was evaluated for its ability to interact with sessile cells. Using confocal laser scanning microscopy, we demonstrated that the drug damaged bacteria within an established biofilm showing that penetration did not limit the activity of this antimicrobial agent against a biofilm. When biofilms were grown during exposure to shear forces and to a continuous medium flow allowing the development of robust structures with a complex architecture, CSA-13 reached the bacteria entrapped in the biofilm within 30 min. The permeabilizing effect of CSA-13 could be associated with the death of the bacteria. In static conditions, the compound did not perturb the architecture of the biofilm. This study confirms the potential of CSA-13 as a new strategy to combat persistent infections involving biofilms formed by P. aeruginosa. © 2013 The Authors. Published by Blackwell Publishing Ltd.
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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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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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Fungal Microbiomes Associated with Green and Non-Green Building Materials
Coombs, Kanistha; Vesper, Stephen; Green, Brett J.; Yermakov, Mikhail; Reponen, Tiina
2018-01-01
Water-damaged buildings can lead to fungal growth and occupant health problems. Green building materials, derived from renewable sources, are increasingly utilized in construction and renovations. However, the question as to what fungi will grow on these green compared to non-green materials, after they get wet, has not been adequately studied. By determining what fungi grow on each type of material, the potential health risks can be more adequately assessed. In this study, we inoculated green and non-green pieces of ceiling tile, composite board, drywall, and flooring with indoor dust containing a complex mixture of naturally occurring fungi. The materials were saturated with water and incubated for two months in a controlled environment. The resulting fungal microbiomes were evaluated using ITS amplicon sequencing. Overall, the richness and diversity of the mycobiomes on each pair of green and non-green pieces were not significantly different. However, different genera dominated on each type of material. For example, Aspergillus spp. had the highest relative abundance on green and non-green ceiling tiles and green composite boards, but Peniophora spp. dominated the non-green composite board. In contrast, Penicillium spp. dominated green and non-green flooring samples. Green gypsum board was dominated by Phialophora spp. and Stachybotrys spp., but non-green gypsum board by Myrothecium spp. These data suggest that water-damaged green and non-green building materials can result in mycobiomes that are dominated by fungal genera whose member species pose different potentials for health risks. PMID:29681691
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Fungal Microbiomes Associated with Green and Non-Green Building Materials.
Coombs, Kanistha; Vesper, Stephen; Green, Brett J; Yermakov, Mikhail; Reponen, Tiina
2017-01-01
Water-damaged buildings can lead to fungal growth and occupant health problems. Green building materials, derived from renewable sources, are increasingly utilized in construction and renovations. However, the question as to what fungi will grow on these green compared to non-green materials, after they get wet, has not been adequately studied. By determining what fungi grow on each type of material, the potential health risks can be more adequately assessed. In this study, we inoculated green and non-green pieces of ceiling tile, composite board, drywall, and flooring with indoor dust containing a complex mixture of naturally occurring fungi. The materials were saturated with water and incubated for two months in a controlled environment. The resulting fungal microbiomes were evaluated using ITS amplicon sequencing. Overall, the richness and diversity of the mycobiomes on each pair of green and non-green pieces were not significantly different. However, different genera dominated on each type of material. For example, Aspergillus spp. had the highest relative abundance on green and non-green ceiling tiles and green composite boards, but Peniophora spp. dominated the non-green composite board. In contrast, Penicillium spp. dominated green and non-green flooring samples. Green gypsum board was dominated by Phialophora spp. and Stachybotrys spp., but non-green gypsum board by Myrothecium spp. These data suggest that water-damaged green and non-green building materials can result in mycobiomes that are dominated by fungal genera whose member species pose different potentials for health risks.
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Lübbert, Christoph; Wendt, Karolin; Feisthammel, Jürgen; Moter, Annette; Lippmann, Norman; Busch, Thilo; Mössner, Joachim; Hoffmeister, Albrecht; Rodloff, Arne C.
2016-01-01
Background Plastic stents used for the treatment of biliary obstruction will become occluded over time due to microbial colonization and formation of biofilms. Treatment of stent-associated cholangitis is often not effective because of inappropriate use of antimicrobial agents or antimicrobial resistance. We aimed to assess the current bacterial and fungal etiology of stent-associated biofilms, with particular emphasis on antimicrobial resistance. Methods Patients with biliary strictures requiring endoscopic stent placement were prospectively enrolled. After the retrieval of stents, biofilms were disrupted by sonication, microorganisms were cultured, and isolates were identified by matrix-associated laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and/or biochemical typing. Finally, minimum inhibitory concentrations (MICs) were determined for various antimicrobial agents. Selected stents were further analyzed by fluorescence in situ hybridization (FISH). Results Among 120 patients (62.5% males, median age 64 years) with biliary strictures (35% malignant, 65% benign), 113 double pigtail polyurethane and 100 straight polyethylene stents were analyzed after a median indwelling time of 63 days (range, 1–1274 days). The stent occlusion rate was 11.5% and 13%, respectively, being associated with a significantly increased risk of cholangitis (38.5% vs. 9.1%, P<0.001). Ninety-five different bacterial and 13 fungal species were detected; polymicrobial colonization predominated (95.8% vs. 4.2%, P<0.001). Enterococci (79.3%), Enterobacteriaceae (73.7%), and Candida spp. (55.9%) were the leading pathogens. Candida species were more frequent in patients previously receiving prolonged antibiotic therapy (63% vs. 46.7%, P = 0.023). Vancomycin-resistant enterococci accounted for 13.7%, extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae with co-resistance to ciprofloxacin accounted for 13.9%, and azole-resistant Candida spp. accounted for
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Lübbert, Christoph; Wendt, Karolin; Feisthammel, Jürgen; Moter, Annette; Lippmann, Norman; Busch, Thilo; Mössner, Joachim; Hoffmeister, Albrecht; Rodloff, Arne C
2016-01-01
Plastic stents used for the treatment of biliary obstruction will become occluded over time due to microbial colonization and formation of biofilms. Treatment of stent-associated cholangitis is often not effective because of inappropriate use of antimicrobial agents or antimicrobial resistance. We aimed to assess the current bacterial and fungal etiology of stent-associated biofilms, with particular emphasis on antimicrobial resistance. Patients with biliary strictures requiring endoscopic stent placement were prospectively enrolled. After the retrieval of stents, biofilms were disrupted by sonication, microorganisms were cultured, and isolates were identified by matrix-associated laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and/or biochemical typing. Finally, minimum inhibitory concentrations (MICs) were determined for various antimicrobial agents. Selected stents were further analyzed by fluorescence in situ hybridization (FISH). Among 120 patients (62.5% males, median age 64 years) with biliary strictures (35% malignant, 65% benign), 113 double pigtail polyurethane and 100 straight polyethylene stents were analyzed after a median indwelling time of 63 days (range, 1-1274 days). The stent occlusion rate was 11.5% and 13%, respectively, being associated with a significantly increased risk of cholangitis (38.5% vs. 9.1%, P<0.001). Ninety-five different bacterial and 13 fungal species were detected; polymicrobial colonization predominated (95.8% vs. 4.2%, P<0.001). Enterococci (79.3%), Enterobacteriaceae (73.7%), and Candida spp. (55.9%) were the leading pathogens. Candida species were more frequent in patients previously receiving prolonged antibiotic therapy (63% vs. 46.7%, P = 0.023). Vancomycin-resistant enterococci accounted for 13.7%, extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae with co-resistance to ciprofloxacin accounted for 13.9%, and azole-resistant Candida spp. accounted for 32.9% of the respective
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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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Bou Zeidan, Marc; Carmona, Lourdes
2013-01-01
Saccharomyces cerevisiae “flor” yeasts have the ability to form a buoyant biofilm at the air-liquid interface of wine. The formation of biofilm, also called velum, depends on FLO11 gene length and expression. FLO11 encodes a cell wall mucin-like glycoprotein with a highly O-glycosylated central domain and an N-terminal domain that mediates homotypic adhesion between cells. In the present study, we tested previously known antimicrobial peptides with different mechanisms of antimicrobial action for their effect on the viability and ability to form biofilm of S. cerevisiae flor strains. We found that PAF26, a synthetic tryptophan-rich cationic hexapeptide that belongs to the class of antimicrobial peptides with cell-penetrating properties, but not other antimicrobial peptides, enhanced biofilm formation without affecting cell viability in ethanol-rich medium. The PAF26 biofilm enhancement required a functional FLO11 but was not accompanied by increased FLO11 expression. Moreover, fluorescence microscopy and flow cytometry analyses showed that the PAF26 peptide binds flor yeast cells and that a flo11 gene knockout mutant lost the ability to bind PAF26 but not P113, a different cell-penetrating antifungal peptide, demonstrating that the FLO11 gene is selectively involved in the interaction of PAF26 with cells. Taken together, our data suggest that the cationic and hydrophobic PAF26 hexapeptide interacts with the hydrophobic and negatively charged cell wall, favoring Flo11p-mediated cell-to-cell adhesion and thus increasing biofilm biomass formation. The results are consistent with previous data that point to glycosylated mucin-like proteins at the fungal cell wall as potential interacting partners for antifungal peptides. PMID:23892742
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Fluid-Structure Interaction in Continuum Models of Bacterial Biofilms
NASA Astrophysics Data System (ADS)
Hicks, Jared A.
Bacterial biofilms are aggregates of cells that adhere to nearly any solid-fluid interface. While many have harmful effects, such as industrial damage and nosocomial infections, certain biofilm species are now generating renewable energy as the fundamental components of Microbial Fuel Cells (MFCs). In an MFC, bacteria consume organic waste and, as they respire, produce free electrons. To do so efficiently, the bacteria must operate at peak metabolic activity, and so require an ample supply of nutrients. But existing MFC systems face several nutrient delivery problems, including clogging and downstream depletion. Ameliorating these problems will require a better understanding of the interplay between structural development and the surrounding fluid flow. In addition to delivering nutrients that affect biofilm growth, the fluid also exerts stresses that cause erosion, detachment, and deformation. These structural changes, in turn, affect the flow and alter the nutrient distribution. To account for this feedback effect, I have developed a continuum model that couples the growth and deformation processes. My model augments an existing growth model with evolution equations derived from Morphoelasticity Theory, by showing that the growth tensor can be directly related to the biofilm velocity potential. This result helps overcome one of the major practical limitations of Morphoelasticity--there is no physical framework for specifying the growth tensor. Through further analysis of the growth tensor, I define the related adjugate and anisotropic growth tensors, which can be more meaningful measures of growth for some models. Under the assumption of small strain, I show that there exists a small correction to the biofilm growth velocity (the accommodation velocity) that represents the effect of the elastic response on the evolution of the biofilm shape. I derive a solvability condition for the accommodation velocity, and show that it leads to a novel evolution equation for
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Sabino, C P; Garcez, A S; Núñez, S C; Ribeiro, M S; Hamblin, M R
2015-08-01
Antimicrobial photodynamic therapy (APDT) combined with endodontic treatment has been recognized as an alternative approach to complement conventional root canal disinfection methods on bacterial biofilms. We developed an in vitro model of bioluminescent Candida albicans biofilm inside curved dental root canals and investigated the microbial reduction produced when different light delivery methods are employed. Each light delivery method was evaluated in respect to the light distribution provided inside curved root canals. After conventional endodontic preparation, teeth were sterilized before canals were contaminated by a bioluminescent strain of C. albicans (CEC789). Methylene blue (90 μM) was introduced into the canals and then irradiated (λ = 660 nm, P = 100 mW, beam diameter = 2 mm) with laser tip either in contact with pulp chamber or within the canal using an optical diffuser fiber. Light distribution was evaluated by CCD camera, and microbial reduction was monitored through bioluminescence imaging. Our findings demonstrated that the bioluminescent C. albicans biofilm model had good reproducibility and uniformity. Light distribution in dental tissue was markedly dependent on the light delivery system, and this strategy was directly related to microbial destruction. Both light delivery systems performed significant fungal inactivation. However, when irradiation was performed with optical diffuser fiber, microbial burden reduction was nearly 100 times more effective. Bioluminescence is an interesting real-time analysis to endodontic C. albicans biofilm inactivation. APDT showed to be an effective way to inactivate C. albicans biofilms. Diffuser fibers provided optimized light distribution inside curved root canals and significantly increased APDT efficiency.
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Sabino, C. P.; Garcez, A. S.; Núñez, S. C.; Ribeiro, M. S.; Hamblin, M. R.
2014-01-01
Antimicrobial photodynamic therapy (APDT) combined with endodontic treatment has been recognized as an alternative approach to complement conventional root canal disinfection methods on bacterial biofilms. We developed an in vitro model of bioluminescent Candida albicans biofilm inside curved dental root canals and investigated the microbial reduction produced when different light delivery methods are employed. Each light delivery method was evaluated in respect to the light distribution provided inside curved root canals. After conventional endodontic preparation, teeth were sterilized before canals were contaminated by a bioluminescent strain of C. albicans (CEC789). Methylene blue (90 µM) was introduced into the canals and then irradiated (λ=660 nm, P=100 mW, beam diameter=2 mm) with laser tip either in contact with pulp chamber or within the canal using an optical diffuser fiber. Light distribution was evaluated by CCD camera, and microbial reduction was monitored through bioluminescence imaging. Our findings demonstrated that the bioluminescent C. albicans biofilm model had good reproducibility and uniformity. Light distribution in dental tissue was markedly dependent on the light delivery system, and this strategy was directly related to microbial destruction. Both light delivery systems performed significant fungal inactivation. However, when irradiation was performed with optical diffuser fiber, microbial burden reduction was nearly 100 times more effective. Bioluminescence is an interesting real-time analysis to endodontic C. albicans biofilm inactivation. APDT showed to be an effective way to inactivate C. albicans biofilms. Diffuser fibers provided optimized light distribution inside curved root canals and significantly increased APDT efficiency. PMID:25060900
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The role of effectors and host immunity in plant-necrotrophic fungal interactions.
Wang, Xuli; Jiang, Nan; Liu, Jinling; Liu, Wende; Wang, Guo-Liang
2014-01-01
Fungal diseases pose constant threats to the global economy and food safety. As the largest group of plant fungal pathogens, necrotrophic fungi cause heavy crop losses worldwide. The molecular mechanisms of the interaction between necrotrophic fungi and plants are complex and involve sophisticated recognition and signaling networks. Here, we review recent findings on the roles of phytotoxin and proteinaceous effectors, pathogen-associated molecular patterns (PAMPs), and small RNAs from necrotrophic fungi. We also consider the functions of damage-associated molecular patterns (DAMPs), the receptor-like protein kinase BIK1, and epigenetic regulation in plant immunity to necrotrophic fungi.
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The role of effectors and host immunity in plant–necrotrophic fungal interactions
Wang, Xuli; Jiang, Nan; Liu, Jinling; Liu, Wende; Wang, Guo-Liang
2014-01-01
Fungal diseases pose constant threats to the global economy and food safety. As the largest group of plant fungal pathogens, necrotrophic fungi cause heavy crop losses worldwide. The molecular mechanisms of the interaction between necrotrophic fungi and plants are complex and involve sophisticated recognition and signaling networks. Here, we review recent findings on the roles of phytotoxin and proteinaceous effectors, pathogen-associated molecular patterns (PAMPs), and small RNAs from necrotrophic fungi. We also consider the functions of damage-associated molecular patterns (DAMPs), the receptor-like protein kinase BIK1, and epigenetic regulation in plant immunity to necrotrophic fungi. PMID:25513773
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Delben, Juliana Aparecida; Zago, Chaiene Evelin; Tyhovych, Natalia; Duarte, Simone; Vergani, Carlos Eduardo
2016-01-01
Considering the ability of atmospheric-pressure cold plasma (ACP) to disrupt the biofilm matrix and rupture cell structure, it can be an efficient tool against virulent oral biofilms. However, it is fundamental that ACP does not cause damage to oral tissue. So, this study evaluated (1) the antimicrobial effect of ACP on single- and dual-species biofilms of Candida albicans and Staphylococcus aureus as well as (2) the biological safety of ACP on in vitro reconstituted oral epithelium. Standardized cell suspensions of each microorganism were prepared for biofilm culture on acrylic resin discs at 37°C for 48 hours. The biofilms were submitted to ACP treatment at 10 mm of plasma tip-to-sample distance during 60 seconds. Positive controls were penicillin G and fluconazole for S. aureus and C. albicans, respectively. The biofilms were analyzed through counting of viable colonies, confocal laser scanning microscopy, scanning electron microscopy and fluorescence microscopy for detection of reactive oxygen species. The in vitro reconstituted oral epithelium was submitted to similar ACP treatment and analyzed through histology, cytotoxocity test (LDH release), viability test (MTT assay) and imunnohistochemistry (Ki67 expression). All plasma-treated biofilms presented significant log10 CFU/mL reduction, alteration in microorganism/biofilm morphology, and reduced viability in comparison to negative and positive controls. In addition, fluorescence microscopy revealed presence of reactive oxygen species in all plasma-treated biofilms. Low cytotoxicity and high viability were observed in oral epithelium of negative control and plasma group. Histology showed neither sign of necrosis nor significant alteration in plasma-treated epithelium. Ki67-positive cells revealed maintenance of cell proliferation in plasma-treated epithelium. Atmospheric-pressure cold plasma is a promissing approach to eliminate single- and dual-species biofilms of C. albicans and S. aureus without having
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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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Frequency of sucrose exposure on the cariogenicity of a biofilm-caries model
Díaz-Garrido, Natalia; Lozano, Carla; Giacaman, Rodrigo A.
2016-01-01
Objective: Although sucrose is considered the most cariogenic carbohydrate in the human diet, the question of how many exposures are needed to induce damage on the hard dental tissues remains unclear. To approach this question, different frequencies of daily sucrose exposure were tested on a relevant biological caries model. Materials and Methods: Biofilms of the Streptococcus mutans were formed on enamel slabs and exposed to cariogenic challenges with 10% sucrose for 5 min at 0, 1, 3, 5, 8, or 10 times per day. After 5 days, biofilms were retrieved to analyze biomass, protein content, viable bacteria, and polysaccharide formation. Enamel demineralization was evaluated by percentage of microhardness loss (percentage surface hardness loss [%SHL]). Results: Biomass, protein content, polysaccharide production, acidogenicity of the biofilm, and %SHL proportionally increased with the number of daily exposures to sucrose (P < 0.05). One daily sucrose exposure was enough to induce 20% more demineralization than the negative unexposed control. Higher frequencies induced greater demineralization and more virulent biofilms, but eight and ten exposures were not different between them in most of the analyzed variables (P > 0.05). Conclusions: Higher sucrose exposure seems to increase cariogenicity, in a frequency-dependent manner, by the modification of bacterial virulent properties. PMID:27403051
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Multispecies Biofilms and Host Responses: “Discriminating the Trees from the Forest”
Peyyala, R.; Ebersole, J.L.
2014-01-01
Periodontal diseases reflect a tissue destructive process of the hard and soft tissues of the periodontium that are initiated by the accumulation of multispecies bacterial biofilms in the subgingival sulcus. This accumulation, in both quantity and quality of bacteria, results in a chronic immunoinflammatory response of the host to control this noxious challenge, leading to collateral damage of the tissues. As knowledge of the characteristics of the host-bacterial interactions in the oral cavity has expanded, new knowledge has become available on the complexity of the microbial challenge and the repertoire of host responses to this challenge. Recent results from the Human Microbiome Project continue to extend the array of taxa, genera, and species of bacteria that inhabit the multiple niches in the oral cavity; however, there is rather sparse information regarding variations in how host cells discriminate commensal from pathogenic species, as well as how the host response is affected by the 3-dimensional architecture and interbacterial interactions that occur in the oral biofilms. This review provides some insights into thes- processes by including existing literature on the biology of nonoral bacterial biofilms, and the more recent literature just beginning to document how the oral cavity responds to multispecies biofilms. PMID:23141757
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Garcia, Lana Glerieide Silva; Guedes, Glaucia Morgana de Melo; da Silva, Maria Lucilene Queiroz; Castelo-Branco, Débora Souza Collares Maia; Sidrim, José Júlio Costa; Cordeiro, Rossana de Aguiar; Rocha, Marcos Fábio Gadelha; Vieira, Rodrigo Silveira; Brilhante, Raimunda Sâmia Nogueira
2018-09-01
Difficulties in the treatment of Candida spp. invasive infections are usually related to the formation of biofilms. The aim of this study was to determine the effects of molecular weight (MW) of chitosan (using high (HMW), medium (MMW) and low (LMW) molecular weight chitosan) on Candida albicans, Candida tropicalis and Candida parapsilosis sensu stricto. The deacetylation degree (DD) and molecular weight M were measured by potentiometric titration and viscosimetry, respectively. The planktonic shape activity was quantified by broth microdilution, and the activity against biofilm was quantified by metabolic activity through XTT 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]- 2H-tetrazolium hydroxide and biomass formation (crystal violet). The influence of chitosan MW on the planktonic form of Candida spp. was strain dependent. Fungal growth decreased with increasing chitosan MW for C. tropicalis and C. parapsilosis, while chitosan MW did not modulate the effect for C. albicans. With regard to the formation of biofilms, in both the adhesion and mature phases, the biomass and metabolic activities of Candida spp. were reduced by about 70% and 80%, respectively for each phase. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Srikantha, Thyagarajan; Huang, Guanghua; Garnaas, Adam M.; Soll, David R.
2011-01-01
Similar multicellular structures can evolve within the same organism that may have different evolutionary histories, be controlled by different regulatory pathways, and play similar but nonidentical roles. In the human fungal pathogen Candida albicans, a quite extraordinary example of this has occurred. Depending upon the configuration of the mating type locus (a/α versus a/a or α/α), C. albicans forms alternative biofilms that appear similar morphologically, but exhibit dramatically different characteristics and are regulated by distinctly different signal transduction pathways. Biofilms formed by a/α cells are impermeable to molecules in the size range of 300 Da to 140 kDa, are poorly penetrated by human polymorphonuclear leukocytes (PMNs), and are resistant to antifungals. In contrast, a/a or α/α biofilms are permeable to molecules in this size range, are readily penetrated by PMNs, and are susceptible to antifungals. By mutational analyses, a/α biofilms are demonstrated to be regulated by the Ras1/cAMP pathway that includes Ras1→Cdc35→cAMP(Pde2—|)→Tpk2(Tpk1)→Efg1→Tec1→Bcr1, and a/a biofilms by the MAP kinase pathway that includes Mfα→Ste2→ (Ste4, Ste18, Cag1)→Ste11→Hst7→Cek2(Cek1)→Tec1. These observations suggest the hypothesis that while the upstream portion of the newly evolved pathway regulating a/a and α/α cell biofilms was derived intact from the upstream portion of the conserved pheromone-regulated pathway for mating, the downstream portion was derived through modification of the downstream portion of the conserved pathway for a/α biofilm formation. C. albicans therefore forms two alternative biofilms depending upon mating configuration. PMID:21829325
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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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Impacts of fungal stalk rot pathogens on physicochemical properties of sorghum grain
USDA-ARS?s Scientific Manuscript database
Stalk rot diseases are among the most ubiquitous and damaging fungal diseases of sorghum worldwide. Although reports of quantitative stalk rot yield losses are available, the impact of stalk rot on the physicochemical attributes of sorghum grain is currently unknown. This study was conducted to test...
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Vidal, Jorge E; Shak, Joshua R; Canizalez-Roman, Adrian
2015-06-01
Clostridium perfringens strains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by the C. perfringens Agr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. Although C. perfringens strains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrB mutant strains were not able to produce biofilms, a ΔluxS mutant produced wild-type levels. The transcript levels of CpAL-regulated cpa and pfoA genes, but not cpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpa and ΔpfoA mutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpb made wild-type levels. Biofilm formation was restored in complemented Δcpa/cpa and ΔpfoA/pfoA strains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation in C. perfringens by increasing levels of certain toxins required to build biofilms. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
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Shak, Joshua R.; Canizalez-Roman, Adrian
2015-01-01
Clostridium perfringens strains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by the C. perfringens Agr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. Although C. perfringens strains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrB mutant strains were not able to produce biofilms, a ΔluxS mutant produced wild-type levels. The transcript levels of CpAL-regulated cpa and pfoA genes, but not cpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpa and ΔpfoA mutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpb made wild-type levels. Biofilm formation was restored in complemented Δcpa/cpa and ΔpfoA/pfoA strains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation in C. perfringens by increasing levels of certain toxins required to build biofilms. PMID:25824838
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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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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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Oral Bacterial and Fungal Microbiome Impacts Colorectal Carcinogenesis.
Klimesova, Klara; Jiraskova Zakostelska, Zuzana; Tlaskalova-Hogenova, Helena
2018-01-01
Host's physiology is significantly influenced by microbiota colonizing the epithelial surfaces. Complex microbial communities contribute to proper mucosal barrier function, immune response, and prevention of pathogen invasion and have many other crucial functions. The oral cavity and large intestine are distant parts of the digestive tract, both heavily colonized by commensal microbiota. Nevertheless, they feature different proportions of major bacterial and fungal phyla, mostly due to distinct epithelial layers organization and different oxygen levels. A few obligate anaerobic strains inhabiting the oral cavity are involved in the pathogenesis of oral diseases. Interestingly, these microbiota components are also enriched in gut inflammatory and tumor tissue. An altered microbiota composition - dysbiosis - and formation of polymicrobial biofilms seem to play important roles in the development of oral diseases and colorectal cancer. In this review, we describe the differences in composition of commensal microbiota in the oral cavity and large intestine and the mechanisms by which microbiota affect the inflammatory and carcinogenic response of the host.
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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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Tran, Phat L; Hammond, Adrienne A; Mosley, Thomas; Cortez, Janette; Gray, Tracy; Colmer-Hamood, Jane A; Shashtri, Mayank; Spallholz, Julian E; Hamood, Abdul N; Reid, Ted W
2009-06-01
Among the most difficult bacterial infections encountered in treating patients are wound infections, which may occur in burn victims, patients with traumatic wounds, necrotic lesions in people with diabetes, and patients with surgical wounds. Within a wound, infecting bacteria frequently develop biofilms. Many current wound dressings are impregnated with antimicrobial agents, such as silver or antibiotics. Diffusion of the agent(s) from the dressing may damage or destroy nearby healthy tissue as well as compromise the effectiveness of the dressing. In contrast, the antimicrobial agent selenium can be covalently attached to the surfaces of a dressing, prolonging its effectiveness. We examined the effectiveness of an organoselenium coating on cellulose discs in inhibiting Pseudomonas aeruginosa and Staphylococcus aureus biofilm formation. Colony biofilm assays revealed that cellulose discs coated with organoselenium completely inhibited P. aeruginosa and S. aureus biofilm formation. Scanning electron microscopy of the cellulose discs confirmed these results. Additionally, the coating on the cellulose discs was stable and effective after a week of incubation in phosphate-buffered saline. These results demonstrate that 0.2% selenium in a coating on cellulose discs effectively inhibits bacterial attachment and biofilm formation and that, unlike other antimicrobial agents, longer periods of exposure to an aqueous environment do not compromise the effectiveness of the coating.
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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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DOE Office of Scientific and Technical Information (OSTI.GOV)
Grigoriev, Igor
The JGI Fungal Genomics Program aims to scale up sequencing and analysis of fungal genomes to explore the diversity of fungi important for energy and the environment, and to promote functional studies on a system level. Combining new sequencing technologies and comparative genomics tools, JGI is now leading the world in fungal genome sequencing and analysis. Over 120 sequenced fungal genomes with analytical tools are available via MycoCosm (www.jgi.doe.gov/fungi), a web-portal for fungal biologists. Our model of interacting with user communities, unique among other sequencing centers, helps organize these communities, improves genome annotation and analysis work, and facilitates new larger-scalemore » genomic projects. This resulted in 20 high-profile papers published in 2011 alone and contributing to the Genomics Encyclopedia of Fungi, which targets fungi related to plant health (symbionts, pathogens, and biocontrol agents) and biorefinery processes (cellulose degradation, sugar fermentation, industrial hosts). Our next grand challenges include larger scale exploration of fungal diversity (1000 fungal genomes), developing molecular tools for DOE-relevant model organisms, and analysis of complex systems and metagenomes.« less
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Safari, Ashkan; Tukovic, Zeljko; Cardiff, Philip; Walter, Maik; Casey, Eoin; Ivankovic, Alojz
2016-02-01
A good understanding of the mechanical stability of biofilms is essential for biofouling management, particularly when mechanical forces are used. Previous biofilm studies lack a damage-based theoretical model to describe the biofilm separation from a surface. The purpose of the current study was to investigate the interfacial separation of a mature biofilm from a rigid glass substrate using a combined experimental and numerical modelling approach. In the current work, the biofilm-glass interfacial separation process was investigated under tensile and shear stresses at the macroscale level, known as modes I and II failure mechanisms respectively. The numerical simulations were performed using a Finite Volume (FV)-based simulation package (OpenFOAM®) to predict the separation initiation using the cohesive zone model (CZM). Atomic force microscopy (AFM)-based retraction curve was used to obtain the separation properties between the biofilm and glass colloid at microscale level, where the CZM parameters were estimated using the Johnson-Kendall-Roberts (JKR) model. In this study CZM is introduced as a reliable method for the investigation of interfacial separation between a biofilm and rigid substrate, in which a high local stress at the interface edge acts as an ultimate stress at the crack tip.This study demonstrated that the total interfacial failure energy measured at the macroscale, was significantly higher than the pure interfacial separation energy obtained by AFM at the microscale, indicating a highly ductile deformation behaviour within the bulk biofilm matrix. The results of this study can significantly contribute to the understanding of biofilm detachments. Copyright © 2015 Elsevier Ltd. All rights reserved.
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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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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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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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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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de Carvalho Dias, Kassia; Barbugli, Paula Aboud; de Patto, Fernanda; Lordello, Virginia Barreto; de Aquino Penteado, Letícia; Medeiros, Alexandra Ivo; Vergani, Carlos Eduardo
2017-06-30
The objective of this study was to better understand the effects of soluble factors from biofilm of single- and mixed-species Candida albicans (C. albicans) and methicillin-sensitive Staphylococcus aureus (MSSA) cultures after 36 h in culture on keratinocytes (NOK-si and HaCaT) and macrophages (J774A.1). Soluble factors from biofilms of C. albicans and MSSA were collected and incubated with keratinocytes and macrophages, which were subsequently evaluated by cell viability assays (MTT). Lactate dehydrogenase (LDH) enzyme release was measured to assess cell membrane damage to keratinocytes. Cells were analysed by brightfield microscopy after 2 and 24 h of exposure to the soluble factors from biofilm. Cell death was detected by labelling apoptotic cells with annexin V and necrotic cells with propidium iodide (PI) and was visualized via fluorescence microscopy. Soluble factors from biofilm were incubated with J774A.1 cells for 24 h; the subsequent production of NO and the cytokines IL-6 and TNF-α was measured by ELISA. The cell viability assays showed that the soluble factors of single-species C. albicans cultures were as toxic as the soluble factors from biofilm of mixed cultures, whereas the soluble factors of MSSA cultures were less toxic than those of C. albicans or mixed cultures. The soluble factors from biofilm of mixed cultures were the most toxic to the NOK-si and HaCaT cells, as confirmed by analyses of PI labelling and cell morphology. Soluble factors from biofilm of single-species MSSA and mixed-species cultures induced the production of IL-6, NO and TNF-α by J744A.1 macrophages. The production of IL-6 and NO induced by the soluble factors from biofilm of mixed cultures was lower than that induced by the soluble factors from biofilm of single-species MSSA cultures, whereas the soluble factors from biofilm of C. albicans cultures induced only low levels of NO. Soluble factors from 36-h-old biofilm of C. albicans and MSSA cultures promoted cell death and
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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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Nance, William C.; Dowd, Scot E.; Samarian, Derek; Chludzinski, Jeffrey; Delli, Joseph; Battista, John; Rickard, Alexander H.
2013-01-01
Objectives Few model systems are amenable to developing multi-species biofilms in parallel under environmentally germane conditions. This is a problem when evaluating the potential real-world effectiveness of antimicrobials in the laboratory. One such antimicrobial is cetylpyridinium chloride (CPC), which is used in numerous over-the-counter oral healthcare products. The aim of this work was to develop a high-throughput microfluidic system that is combined with a confocal laser scanning microscope (CLSM) to quantitatively evaluate the effectiveness of CPC against oral multi-species biofilms grown in human saliva. Methods Twenty-four-channel BioFlux microfluidic plates were inoculated with pooled human saliva and fed filter-sterilized saliva for 20 h at 37°C. The bacterial diversity of the biofilms was evaluated by bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP). The antimicrobial/anti-biofilm effect of CPC (0.5%–0.001% w/v) was examined using Live/Dead stain, CLSM and 3D imaging software. Results The analysis of biofilms by bTEFAP demonstrated that they contained genera typically found in human dental plaque. These included Aggregatibacter, Fusobacterium, Neisseria, Porphyromonas, Streptococcus and Veillonella. Using Live/Dead stain, clear gradations in killing were observed when the biofilms were treated with CPC between 0.5% and 0.001% w/v. At 0.5% (w/v) CPC, 90% of the total signal was from dead/damaged cells. Below this concentration range, less killing was observed. In the 0.5%–0.05% (w/v) range CPC penetration/killing was greatest and biofilm thickness was significantly reduced. Conclusions This work demonstrates the utility of a high-throughput microfluidic–CLSM system to grow multi-species oral biofilms, which are compositionally similar to naturally occurring biofilms, to assess the effectiveness of antimicrobials. PMID:23800904
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Dwivedi, Sourabh; Wahab, Rizwan; Khan, Farheen; Mishra, Yogendra K.; Musarrat, Javed; Al-Khedhairy, Abdulaziz A.
2014-01-01
The formation of bacterial biofilm is a major challenge in clinical applications. The main aim of this study is to describe the synthesis, characterization and biocidal potential of zinc oxide nanoparticles (NPs) against bacterial strain Pseudomonas aeruginosa. These nanoparticles were synthesized via soft chemical solution process in a very short time and their structural properties have been investigated in detail by using X-ray diffraction and transmission electron microscopy measurements. In this work, the potential of synthesized ZnO-NPs (∼10–15 nm) has been assessed in-vitro inhibition of bacteria and the formation of their biofilms was observed using the tissue culture plate assays. The crystal violet staining on biofilm formation and its optical density revealed the effect on biofilm inhibition. The NPs at a concentration of 100 µg/mL significantly inhibited the growth of bacteria and biofilm formation. The biofilm inhibition by ZnO-NPs was also confirmed via bio-transmission electron microscopy (Bio-TEM). The Bio-TEM analysis of ZnO-NPs treated bacteria confirmed the deformation and damage of cells. The bacterial growth in presence of NPs concluded the bactericidal ability of NPs in a concentration dependent manner. It has been speculated that the antibacterial activity of NPs as a surface coating material, could be a feasible approach for controlling the pathogens. Additionally, the obtained bacterial solution data is also in agreement with the results from statistical analytical methods. PMID:25402188
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Dwivedi, Sourabh; Wahab, Rizwan; Khan, Farheen; Mishra, Yogendra K; Musarrat, Javed; Al-Khedhairy, Abdulaziz A
2014-01-01
The formation of bacterial biofilm is a major challenge in clinical applications. The main aim of this study is to describe the synthesis, characterization and biocidal potential of zinc oxide nanoparticles (NPs) against bacterial strain Pseudomonas aeruginosa. These nanoparticles were synthesized via soft chemical solution process in a very short time and their structural properties have been investigated in detail by using X-ray diffraction and transmission electron microscopy measurements. In this work, the potential of synthesized ZnO-NPs (∼ 10-15 nm) has been assessed in-vitro inhibition of bacteria and the formation of their biofilms was observed using the tissue culture plate assays. The crystal violet staining on biofilm formation and its optical density revealed the effect on biofilm inhibition. The NPs at a concentration of 100 µg/mL significantly inhibited the growth of bacteria and biofilm formation. The biofilm inhibition by ZnO-NPs was also confirmed via bio-transmission electron microscopy (Bio-TEM). The Bio-TEM analysis of ZnO-NPs treated bacteria confirmed the deformation and damage of cells. The bacterial growth in presence of NPs concluded the bactericidal ability of NPs in a concentration dependent manner. It has been speculated that the antibacterial activity of NPs as a surface coating material, could be a feasible approach for controlling the pathogens. Additionally, the obtained bacterial solution data is also in agreement with the results from statistical analytical methods.
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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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Discrimination of fungal infections on grape berries via spectral signatures
NASA Astrophysics Data System (ADS)
Molitor, Daniel; Griesser, Michaela; Schütz, Erich; Khuen, Marie-Therese; Schefbeck, Christa; Ronellenfitsch, Franz Kai; Schlerf, Martin; Beyer, Marco; Schoedl-Hummel, Katharina; Anhalt, Ulrike; Forneck, Astrid
2016-04-01
The fungal pathogens Botrytis cinerea and Penicillium expansum are causing economic damages on grapevine worldwide. Especially the simultaneous occurrence of both often results in off-flavours highly threatening wine quality. For the classification of grape quality as well as for the determination of targeted enological treatments, the knowledge of the level of fungal attack is of highest interest. However, visual assessment and pathogen discrimination are cost-intensive. Consequently, a pilot laboratory study aimed at (i) detecting differences in spectral signatures between grape berry lots with different levels of infected berries (B. cinerea and/or P. expansum) and (ii) detecting links between spectral signatures and biochemical as well as quantitative molecular markers for fungal attack. To this end, defined percentages (infection levels) of table grape berries were inoculated with fungal spore suspensions. Spectral measurements were taken using a FieldSpec 3 Max spectroradiometer (ASD Inc., Boulder/Colorado, USA) in regular intervals after inoculation. In addition, fungal attack was determined enzymatically) and quantitatively (real-time PCR). In addition, gluconic acid concentrations (as a potential markers for fungal attack) were determined photometrically. Results indicate that based on spectral signatures, a discrimination of P. expansum and B. cinerea infections as well as of different B. cinerea infection levels is possible. Real-time PCR analyses, detecting DNA levels of both fungi, showed yet a low detection level. Whereas the gluconic acid concentrations turned out to be specific for the two fungi tested (B. cinerea vs. P. expansum) and thus may serve as a differentiating biochemical marker. Correlation analyses between spectral measurements and biological data (gluconic acid concentrations, fungi DNA) as well as further common field and laboratory trials are targeted.
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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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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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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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NASA Astrophysics Data System (ADS)
Vijayakumar, S.; Vinoj, G.; Malaikozhundan, B.; Shanthi, S.; Vaseeharan, B.
2015-02-01
In this study, zinc oxide nanoparticles were biologically synthesized using the leaf extract of Plectranthus amboinicus (Pam-ZnO NPs). The synthesized Pam-ZnO NPs were characterized by UV-Vis spectrophotometer, FTIR, TEM and XRD analysis. TEM analysis of Pam-ZnO NPs showed the average size of about 20-50 nm. Pam-ZnO NPs control the growth of methicillin-resistant Staphylococcus aureus biofilms (MRSA ATCC 33591) at the concentration of 8-10 μg/ml. Confocal laser scanning microscope (CLSM) images revealed that Pam-ZnO NPs strongly inhibited the biofilm forming ability of S. aureus. In addition, Pam-ZnO NPs showed 100% mortality of fourth instar mosquito larvae of Anopheles stephensi, Culex quinquefasciatus and Culex tritaeniorhynchus at the concentration of 8 and 10 μg/ml. The histopathological studies of Pam-ZnO NPs treated A. stephensi and C. quinquefasciatus larvae revealed the presence of damaged cells and tissues in the mid-gut. The damaged tissues suffered major changes including rupture and disintegration of epithelial layer and cellular vacuolization. The present study conclude that Pam-ZnO NPs showed effective control of S. aureus biofilms and mosquito larvae by damaging the mid gut cells.
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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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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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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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Emerson, Joanne B; Keady, Patricia B; Brewer, Tess E; Clements, Nicholas; Morgan, Emily E; Awerbuch, Jonathan; Miller, Shelly L; Fierer, Noah
2015-03-03
Flood-damaged homes typically have elevated microbial loads, and their occupants have an increased incidence of allergies, asthma, and other respiratory ailments, yet the microbial communities in these homes remain under-studied. Using culture-independent approaches, we characterized bacterial and fungal communities in homes in Boulder, CO, USA 2-3 months after the historic September, 2013 flooding event. We collected passive air samples from basements in 50 homes (36 flood-damaged, 14 non-flooded), and we sequenced the bacterial 16S rRNA gene (V4-V5 region) and the fungal ITS1 region from these samples for community analyses. Quantitative PCR was used to estimate the abundances of bacteria and fungi in the passive air samples. Results indicate significant differences in bacterial and fungal community composition between flooded and non-flooded homes. Fungal abundances were estimated to be three times higher in flooded, relative to non-flooded homes, but there were no significant differences in bacterial abundances. Penicillium (fungi) and Pseudomonadaceae and Enterobacteriaceae (bacteria) were among the most abundant taxa in flooded homes. Our results suggest that bacterial and fungal communities continue to be affected by flooding, even after relative humidity has returned to baseline levels and remediation has removed any visible evidence of flood damage.
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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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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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... fungal eye infections . Fungal eye infections are extremely rare, but they can be very serious. The most common way for someone to develop a fungal eye infection is as a result of an eye injury, particularly if the injury was caused by plant material such as a stick or a thorn. ...
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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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Curt, Sèverine; Subirade, Muriel; Rouabhia, Mahmoud
2009-06-01
This study presents results on soy protein isolate (SPI) biofilm production and the corresponding effect on the stability and toxicity of the derived films. SPI biofilms were prepared from SPI chemically treated with formaldehyde at various concentrations (0%, 1%, 2%, and 3%) as cross-linking agents. In vitro SPI biofilm degradation was evaluated as a function of water absorption leading to weight and size modifications. SPI biofilm toxicity was determined as a function of human keratinocyte and fibroblast adhesion, viability, and proliferation. Cytokine gene expression supported this using reverse transcriptase polymerase chain reaction techniques. Our results confirm that SPI can be used to produce biofilms. The resulting SPI biofilms without formaldehyde swell significantly, which leads to their physical instability. Formaldehyde treatment enhanced the mechanical properties of these biofilms by covalently cross-linking polypeptide chains. The decreased water absorption was dependent on the amount of formaldehyde present. SPI biofilms with 2% and 3% formaldehyde were highly stable and easier to manipulate than those with 0% and 1% formaldehyde. Tissue culture analyses revealed that the SPI biofilms without formaldehyde were non-toxic to human cells (keratinocytes and fibroblasts). The presence of formaldehyde in biofilms did not have any effects on cell viability, adhesion, or proliferation. This was supported by the high level of messenger RNA expression of interleukin-1 beta (IL-1beta) and tumor necrosis factor alpha by the keratinocytes and of IL-6 and IL-8 by the fibroblasts. Overall, we produced a stable, non-toxic soy protein support, which may be of potential interest in medical applications such as cell culture matrices and damaged tissue replacement.
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NASA Astrophysics Data System (ADS)
Beaussart, Audrey; El-Kirat-Chatel, Sofiane; Fontaine, Thierry; Latgé, Jean-Paul; Dufrêne, Yves F.
2015-09-01
Many fungal pathogens produce cell surface polysaccharides that play essential roles in host-pathogen interactions. In Aspergillus fumigatus, the newly discovered polysaccharide galactosaminogalactan (GAG) mediates adherence to a variety of substrates through molecular mechanisms that are poorly understood. Here we use atomic force microscopy to unravel the localization and adhesion of GAG on living fungal cells. Using single-molecule imaging with tips bearing anti-GAG antibodies, we found that GAG is massively exposed on wild-type (WT) germ tubes, consistent with the notion that this glycopolymer is secreted by the mycelium of A. fumigatus, while it is lacking on WT resting conidia and on germ tubes from a mutant (Δuge3) deficient in GAG. Imaging germ tubes with tips bearing anti-β-glucan antibodies shows that exposure of β-glucan is strongly increased in the Δuge3 mutant, indicating that this polysaccharide is masked by GAG during hyphal growth. Single-cell force measurements show that expression of GAG on germ tubes promotes specific adhesion to pneumocytes and non-specific adhesion to hydrophobic substrates. These results provide a molecular foundation for the multifunctional adhesion properties of GAG, thus suggesting it could be used as a potential target in anti-adhesion therapy and immunotherapy. Our methodology represents a powerful approach for characterizing the nanoscale organization and adhesion of cell wall polysaccharides during fungal morphogenesis, thereby contributing to increase our understanding of their role in biofilm formation and immune responses.
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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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Marioni, Juliana; da Silva, María Angel; Cabrera, José Luis; Montoya, Susana C Núñez; Paraje, María Gabriela
2016-11-15
Candida tropicalis is increasingly becoming among the most commonly isolated pathogens causing fungal infections with an important biofilm-forming capacity. This study addresses the antifungal effect of rubiadin (AQ1) and rubiadin 1-methyl ether (AQ2), two photosensitizing anthraquinones (AQs) isolated from Heterophyllaea pustulata, against C. tropicalis biofilms, by studying the cellular stress and antioxidant response in two experimental conditions: darkness and irradiation. The combination with Amphotericin B (AmB) was assayed to evaluate the synergic effect. Biofilms of clinical isolates and reference strain of Candida tropicalis were treated with AQs (AQ1 or AQ2) and/or AmB, and the biofilms depletion was studied by crystal violet and confocal scanning laser microscopy (CSLM). The oxidant metabolites production and the response of antioxidant defense system were also evaluated under dark and irradiation conditions, being the light a trigger for photo-activation of the AQs. The Reactive Oxygen Species (ROS) were detected by the reduction of Nitro Blue Tetrazolium test, and Reactive Nitrogen Intermediates (RNI) by the Griess assay. ROS accumulation was also detected inside biofilms by using 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) probe, which was visualized by CSLM. Superoxide dismutase (SOD) activity and the total antioxidant capacity of biofilms were measured by spectrophotometric methods. The minimun inhibitory concentration for sessile cells (SMIC) was determined for each AQs and AmB. The fractional inhibitory concentration index (FICI) was calculated for the combinations of each AQ with AmB by the checkerboard microdilution method. Biofilm reduction of both strains was more effective with AQ1 than with AQ2. The antifungal effect was mediated by an oxidative and nitrosative stress under irradiation, with a significant accumulation of endogenous ROS detected by CSLM and an increase in the SOD activity. Thus, the prooxidant-antioxidant balance was
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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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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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Cui, Xiaochun; Huo, Mingxin; Chen, Congli; Yu, Zhisen; Zhou, Chen; Li, Anran; Qiao, Bingqian; Zhou, Dandan; Crittenden, John C
2018-09-01
Residual Al(III) (at low concentration) is common in water treatment plants (WTPs) and is associated with bacteria. We hypothesize that Al(III) accelerate biofouling due to its hydrolysis and hormesis characteristics, as compared with other cations. To verify this, we elaborated the roles of Al(III) at low concentrations on the biofilm formation. Al(III) hormesis (<2.0mg/L) stimulated bacteria growth increased by ~3.7 times, and extracellular polymeric substances production also enhanced. Al(III) flocculation resulted in the suspended cells precipitation instantly, for Al(III) dosages of 0.6 and 2.0mg/L and the concentration of Al(III) decreased by 0.07 and 0.14mg/L, respectively. Al(III) poisoned the bridged bacterial cells and decreased their ATP by 22.36% and 55.91%, respectively. Al(III) formed polymer presented strong affinity with bacterial outer membrane, and this damaged the bacterial outer membrane. This caused proteins to leak at the combined point. Al-polymer bound to NH 2 and/or NH on the leaked protein, contributed to biofilm formation. Biofilm maturity was aided by polysaccharides, which shielded Al(III) toxicity for the formed biofilm. Thus, the biofilm exhibited a distinguished double-layer microstructure, principally with proteins and inactivated cells at the bottom, polysaccharides and activated cells at the top. Thus, hormesis and flocculation caused by low concentration Al(III) mutually promoted each other, and together accelerated biofilm formation. Copyright © 2018 Elsevier B.V. All rights reserved.
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Mercier, Anne; Gravouil, Kevin; Aucher, Willy; Brosset-Vincent, Sandra; Kadri, Linette; Colas, Jenny; Bouchon, Didier; Ferreira, Thierry
2017-02-21
With the ever-increasing volume of polymer wastes and their associated detrimental impacts on the environment, the plastic life cycle has drawn increasing attention. Here, eight commercial polymers selected from biodegradable to environmentally persistent materials, all formulated under a credit card format, were incubated in an outdoor compost to evaluate their fate over time and to profile the microbial communities colonizing their surfaces. After 450 days in compost, the samples were all colonized by multispecies biofilms, these latest displaying different amounts of adhered microbial biomass and significantly distinct bacterial and fungal community compositions depending on the substrate. Interestingly, colonization experiments on the eight polymers revealed a large core of shared microbial taxa, predominantly composed of microorganisms previously reported from environments contaminated with petroleum hydrocarbons or plastics debris. These observations suggest that biofilms may contribute to the alteration process of all the polymers studied. Actually, four substrates, independently of their assignment to a polymer group, displayed a significant deterioration, which might be attributed to biologically mediated mechanisms. Relevantly, the deterioration appears strongly associated with the formation of a high-cell density biofilm onto the polymer surfaces. The analysis of various surface properties revealed that roughness and hydrophilicity are likely prominent parameters for driving the biological interactions with the polymers.
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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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Zheng, He; Kim, Jaekuk; Liew, Mathew; Yan, John K.; Herrera, Oscar; Bok, JinWoo; Kelleher, Neil L.; Keller, Nancy P.; Wang, Yun
2014-01-01
Summary Background Filamentous fungi and bacteria form mixed-species biofilms in nature and diverse clinical contexts. They secrete a wealth of redox-active small molecule secondary metabolites, which are traditionally viewed as toxins that inhibit growth of competing microbes. Results Here we report that these “toxins” can act as interspecies signals, affecting filamentous fungal development via oxidative stress regulation. Specifically, in co-culture biofilms, Pseudomonas aeruginosa phenazine-derived metabolites differentially modulated Aspergillus fumigatus development, shifting from weak vegetative growth to induced asexual sporulation (conidiation) along a decreasing phenazine gradient. The A. fumigatus morphological shift correlated with the production of phenazine radicals and concomitant reactive oxygen species (ROS) production generated by phenazine redox cycling. Phenazine conidiation signaling was conserved in the genetic model A. nidulans, and mediated by NapA, a homolog of AP-1-like bZIP transcription factor, which is essential for the response to oxidative stress in humans, yeast, and filamentous fungi. Expression profiling showed phenazine treatment induced a NapA-dependent response of the global oxidative stress metabolome including the thioredoxin, glutathione and NADPH-oxidase systems. Conidiation induction in A. nidulans by another microbial redox-active secondary metabolite, gliotoxin, also required NapA. Conclusions This work highlights that microbial redox metabolites are key signals for sporulation in filamentous fungi, which are communicated through an evolutionarily conserved eukaryotic stress response pathway. It provides a foundation for interspecies signaling in environmental and clinical biofilms involving bacteria and filamentous fungi. PMID:25532893
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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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Levi-Polyachenko, Nicole; Young, Christie; MacNeill, Christopher; Braden, Amy; Argenta, Louis; Reid, Sean
2014-11-01
The aim of this study was to demonstrate that multi-wall carbon nanotubes can be functionalised with antibodies to group A streptoccocus (GAS) for targeted photothermal ablation of planktonic and biofilm residing bacteria. Antibodies for GAS were covalently attached to carboxylated multi-wall carbon nanotubes and incubated with either planktonic or biofilm GAS. Bacterium was then exposed to 1.3 W/cm(2) of 800 nm light for 10-120 s, and then serially diluted onto agar plates from which the number of colony forming units was determined. Photothermal ablation of GAS on the surface of full thickness ex vivo porcine skin and histological sectioning were done to examine damage in adjacent tissue. Approximately 14% of the GAS antibody-functionalised nanotubes attached to the bacterium, and this amount was found to be capable of inducing photothermal ablation of GAS upon exposure to 1.3 W/cm(2) of 800 nm light. Cell viability was not decreased upon exposure to nanotubes or infrared light alone. Compared to carboxylated multi-wall carbon nanotubes, antibody-labelled nanotubes enhanced killing in both planktonic and biofilm GAS in conjunction with infrared light. Analysis of GAS photothermally ablated in direct contact with ex vivo porcine skin shows that heat sufficient for killing GAS remains localised and does not cause collateral damage in tissue adjacent to the treated area. The results of this study support the premise that carbon nanotubes may be effectively utilised as highly localised photothermal agents with the potential for translation into the clinical treatment of bacterial infections of soft tissue.
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Information transmission in microbial and fungal communication: from classical to quantum.
Majumdar, Sarangam; Pal, Sukla
2018-06-01
Microbes have their own communication systems. Secretion and reception of chemical signaling molecules and ion-channels mediated electrical signaling mechanism are yet observed two special ways of information transmission in microbial community. In this article, we address the aspects of various crucial machineries which set the backbone of microbial cell-to-cell communication process such as quorum sensing mechanism (bacterial and fungal), quorum sensing regulated biofilm formation, gene expression, virulence, swarming, quorum quenching, role of noise in quorum sensing, mathematical models (therapy model, evolutionary model, molecular mechanism model and many more), synthetic bacterial communication, bacterial ion-channels, bacterial nanowires and electrical communication. In particular, we highlight bacterial collective behavior with classical and quantum mechanical approaches (including quantum information). Moreover, we shed a new light to introduce the concept of quantum synthetic biology and possible cellular quantum Turing test.
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Guisbiers, Grégory; Lara, Humberto H; Mendoza-Cruz, Ruben; Naranjo, Guillermo; Vincent, Brandy A; Peralta, Xomalin G; Nash, Kelly L
2017-04-01
Selenoproteins play an important role in the human body by accomplishing essential biological functions like oxido-reductions, antioxidant defense, thyroid hormone metabolism and immune response; therefore, the possibility to synthesize selenium nanoparticles free of any contaminants is exciting for future nano-medical applications. This paper reports the first synthesis of selenium nanoparticles by femtosecond pulsed laser ablation in de-ionized water. Those pure nanoparticles have been successfully used to inhibit the formation of Candida albicans biofilms. Advanced electron microscopy images showed that selenium nanoparticles easily adhere on the biofilm, then penetrate into the pathogen, and consequently damage the cell structure by substituting with sulfur. 50% inhibition of Candida albicans biofilm was obtained at only 25 ppm. Finally, the two physical parameters proved to affect strongly the viability of Candida albicans are the crystallinity and particle size. Copyright © 2016 Elsevier Inc. All rights reserved.
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Zhou, Yabin; Wang, Ganggang; Li, Yutang; Liu, Yang; Song, Yu; Zheng, Wenshuai; Zhang, Ning; Hu, Xiaoyan; Yan, Shikun
2012-01-01
The increase in drug resistance and invasion caused by biofilm formation brings enormous challenges to the management of Candida infection. Aspirin's antibiofilm activity in vitro was discovered recently. The spectrophotometric method and the XTT {2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide} reduction assay used for data generation make it possible to evaluate fungal biofilm growth accurately. The combined use of the most commonly used methods, the fractional inhibitory concentration index (FICI) and a newly developed method, the ΔE model, which uses the concentration-effect relationship over the whole concentration range instead of using the MIC index alone, makes the interpretation of results more reliable. As an attractive tool for studying the pharmacodynamics of antimicrobial agents, time-kill curves can provide detailed information about antimicrobial efficacy as a function of both time and concentration. In the present study, in vitro interactions between aspirin (acetylsalicylic acid [ASA]) and amphotericin B (AMB) against planktonic cells and biofilm cells of Candida albicans and C. parapsilosis were evaluated by the checkerboard microdilution method and the time-kill test. Synergistic and indifferent effects were found for the combination of ASA and AMB against planktonic cells, while strong synergy was found against biofilm cells analyzed by FICI. The ΔE model gave more consistent results with FICI. The positive interactions in concentration were also confirmed by the time-kill test. Moreover, this approach also revealed the pharmacodynamics changes of ASA and synergistic action on time. Our findings suggest a potential clinical use for combination therapy with ASA and AMB to augment activity against biofilm-associated infections. PMID:22391539
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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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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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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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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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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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Lee, S H I; Cappato, L P; Corassin, C H; Cruz, A G; Oliveira, C A F
2016-03-01
This research investigated the removal of adherent cells of 4 strains of Staphylococcus aureus and 1 Listeria monocytogenes strain (previously isolated from dairy plants) from polystyrene microtiter plates using peracetic acid (PAA, 0.5%) for 15, 30, 60, and 120 s, and the inactivation of biofilms formed by those strains on stainless steel coupons using the same treatment times. In the microtiter plates, PAA removed all S. aureus at 15 s compared with control (no PAA treatment). However, L. monocytogenes biofilm was not affected by any PAA treatment. On the stainless steel surface, epifluorescence microscopy using LIVE/DEAD staining (BacLight, Molecular Probes/Thermo Fisher Scientific, Eugene, OR) showed that all strains were damaged within 15 s, with almost 100% of cells inactivated after 30 s. Results of this trial indicate that, although PAA was able to inactivate both S. aureus and L. monocytogenes monospecies biofilms on stainless steel, it was only able to remove adherent cells of S. aureus from polystyrene microplates. The correct use of PAA is critical for eliminating biofilms formed by S. aureus strains found in dairy plants, although further studies are necessary to determine the optimal PAA treatment for removing biofilms of L. monocytogenes. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
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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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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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[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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Nayak, Ajay P.; Green, Brett J.; Beezhold, Donald H.
2015-01-01
Hemolysins are a class of proteins defined by their ability to lyse red cells but have been described to exhibit pleiotropic functions. These proteins have been extensively studied in bacteria and more recently in fungi. Within the last decade, a number of studies have characterized fungal hemolysins and revealed a fascinating yet diverse group of proteins. The purpose of this review is to provide a synopsis of the known fungal hemolysins with an emphasis on those belonging to the aegerolysin protein family. New insight and perspective into fungal hemolysins in biotechnology and health are additionally presented. PMID:22769586
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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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De Toledo, Luciani Gaspar; Ramos, Matheus Aparecido Dos Santos; Spósito, Larissa; Castilho, Elza Maria; Pavan, Fernando Rogério; Lopes, Érica De Oliveira; Zocolo, Guilherme Julião; Silva, Francisca Aliny Nunes; Soares, Tigressa Helena; dos Santos, André Gonzaga; Bauab, Taís Maria; De Almeida, Margarete Teresa Gottardo
2016-01-01
Background: The incidence of fungal infections, especially those caused by Candida yeasts, has increased over the last two decades. However, the indicated therapy for fungal control has limitations. Hence, medicinal plants have emerged as an alternative in the search for new antifungal agents as they present compounds, such as essential oils, with important biological effects. Published data demonstrate important pharmacological properties of the essential oil of Cymbopogon nardus (L.) Rendle; these include anti-tumor, anti-nociceptive, and antibacterial activities, and so an investigation of this compound against pathogenic fungi is interesting. Objective: The aim of this study was to evaluate the chemical composition and biological potential of essential oil (EO) obtained from the leaves of C. nardus focusing on its antifungal profile against Candida species. Methods: The EO was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). Testing of the antifungal potential against standard and clinical strains was performed by determining the minimal inhibitory concentration (MIC), time-kill, inhibition of Candida albicans hyphae growth, and inhibition of mature biofilms. Additionally, the cytotoxicity was investigated by the IC50 against HepG-2 (hepatic) and MRC-5 (fibroblast) cell lines. Results: According to the chemical analysis, the main compounds of the EO were the oxygen-containing monoterpenes: citronellal, geranial, geraniol, citronellol, and neral. The results showed important antifungal potential for all strains tested with MIC values ranging from 250 to 1000 μg/mL, except for two clinical isolates of C. tropicalis (MIC > 1000 μg/mL). The time-kill assay showed that the EO inhibited the growth of the yeast and inhibited hyphal formation of C. albicans strains at concentrations ranging from 15.8 to 1000 μg/mL. Inhibition of mature biofilms of strains of C. albicans, C. krusei and C. parapsilosis occurred at a
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De Toledo, Luciani Gaspar; Ramos, Matheus Aparecido Dos Santos; Spósito, Larissa; Castilho, Elza Maria; Pavan, Fernando Rogério; Lopes, Érica De Oliveira; Zocolo, Guilherme Julião; Silva, Francisca Aliny Nunes; Soares, Tigressa Helena; Dos Santos, André Gonzaga; Bauab, Taís Maria; De Almeida, Margarete Teresa Gottardo
2016-08-09
The incidence of fungal infections, especially those caused by Candida yeasts, has increased over the last two decades. However, the indicated therapy for fungal control has limitations. Hence, medicinal plants have emerged as an alternative in the search for new antifungal agents as they present compounds, such as essential oils, with important biological effects. Published data demonstrate important pharmacological properties of the essential oil of Cymbopogon nardus (L.) Rendle; these include anti-tumor, anti-nociceptive, and antibacterial activities, and so an investigation of this compound against pathogenic fungi is interesting. The aim of this study was to evaluate the chemical composition and biological potential of essential oil (EO) obtained from the leaves of C. nardus focusing on its antifungal profile against Candida species. The EO was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). Testing of the antifungal potential against standard and clinical strains was performed by determining the minimal inhibitory concentration (MIC), time-kill, inhibition of Candida albicans hyphae growth, and inhibition of mature biofilms. Additionally, the cytotoxicity was investigated by the IC50 against HepG-2 (hepatic) and MRC-5 (fibroblast) cell lines. According to the chemical analysis, the main compounds of the EO were the oxygen-containing monoterpenes: citronellal, geranial, geraniol, citronellol, and neral. The results showed important antifungal potential for all strains tested with MIC values ranging from 250 to 1000 μg/mL, except for two clinical isolates of C. tropicalis (MIC > 1000 μg/mL). The time-kill assay showed that the EO inhibited the growth of the yeast and inhibited hyphal formation of C. albicans strains at concentrations ranging from 15.8 to 1000 μg/mL. Inhibition of mature biofilms of strains of C. albicans, C. krusei and C. parapsilosis occurred at a concentration of 10× MIC. The values of the IC50
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Backlund, Christopher J; Worley, Brittany V; Schoenfisch, Mark H
2016-01-01
The effect of nitric oxide (NO)-releasing dendrimer hydrophobicity on Streptococcus mutans killing and biofilm disruption was examined at pH 7.4 and 6.4, the latter relevant to dental caries. Generation 1 (G1) poly(amidoamine) (PAMAM) dendrimers were modified with alkyl epoxides to generate propyl-, butyl-, hexyl-, octyl-, and dodecyl-functionalized dendrimers. The resulting secondary amines were reacted with NO to form N-diazeniumdiolate NO donor-modified dendrimer scaffolds (total NO ∼1μmol/mg). The bactericidal action of the NO-releasing dendrimers against both planktonic and biofilm-based S. mutans proved greatest with increasing alkyl chain length and at lower pH. Improved bactericidal efficacy at pH 6.4 was attributed to increased scaffold surface charge that enhanced dendrimer-bacteria association and ensuing membrane damage. For shorter alkyl chain (i.e., propyl and butyl) dendrimer modifications, increased antibacterial action at pH 6.4 was due to faster NO-release kinetics from proton-labile N-diazeniumdiolate NO donors. Octyl- and dodecyl-modified PAMAM dendrimers proved most effective for eradicating S. mutans biofilms with NO release mitigating dendrimer scaffold cytotoxicity. We report the antibacterial and anti-biofilm efficacy of dual-action nitric oxide (NO)-releasing dendrimers against S. mutans, an etiological agent in dental caries. This work was undertaken to enhance the anti-biofilm action of these scaffolds by employing various alkyl chain modifications. Furthermore, we evaluated the ability of NO to eradicate cariogenic biofilms. We found that at the lower pH associated with dental caries (pH ∼6.4), NO has a more pronounced antibacterial effect for alkyl modifications less capable of biofilm penetration and membrane disruption. Of greatest significance, we introduce dendrimers as a new macromolecular antibacterial agent against the cariogenic bacteria S. mutans. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All
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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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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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Vijayakumar, S; Vinoj, G; Malaikozhundan, B; Shanthi, S; Vaseeharan, B
2015-02-25
In this study, zinc oxide nanoparticles were biologically synthesized using the leaf extract of Plectranthus amboinicus (Pam-ZnO NPs). The synthesized Pam-ZnO NPs were characterized by UV-Vis spectrophotometer, FTIR, TEM and XRD analysis. TEM analysis of Pam-ZnO NPs showed the average size of about 20-50 nm. Pam-ZnO NPs control the growth of methicillin-resistant Staphylococcus aureus biofilms (MRSA ATCC 33591) at the concentration of 8-10 μg/ml. Confocal laser scanning microscope (CLSM) images revealed that Pam-ZnO NPs strongly inhibited the biofilm forming ability of S. aureus. In addition, Pam-ZnO NPs showed 100% mortality of fourth instar mosquito larvae of Anopheles stephensi, Culex quinquefasciatus and Culex tritaeniorhynchus at the concentration of 8 and 10 μg/ml. The histopathological studies of Pam-ZnO NPs treated A. stephensi and C. quinquefasciatus larvae revealed the presence of damaged cells and tissues in the mid-gut. The damaged tissues suffered major changes including rupture and disintegration of epithelial layer and cellular vacuolization. The present study conclude that Pam-ZnO NPs showed effective control of S. aureus biofilms and mosquito larvae by damaging the mid gut cells. Copyright © 2014 Elsevier B.V. All rights reserved.
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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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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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High speed sorting of Fusarium-damaged wheat kernels
USDA-ARS?s Scientific Manuscript database
Recent studies have found that resistance to Fusarium fungal infection can be inherited in wheat from one generation to another. However, there is not yet available a cost effective method to separate Fusarium-damaged wheat kernels from undamaged kernels so that wheat breeders can take advantage of...
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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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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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Augimeri, Richard V.; Varley, Andrew J.; Strap, Janice L.
2015-01-01
Bacterial cellulose (BC) serves as a molecular glue to facilitate intra- and inter-domain interactions in nature. Biosynthesis of BC-containing biofilms occurs in a variety of Proteobacteria that inhabit diverse ecological niches. The enzymatic and regulatory systems responsible for the polymerization, exportation, and regulation of BC are equally as diverse. Though the magnitude and environmental consequences of BC production are species-specific, the common role of BC-containing biofilms is to establish close contact with a preferred host to facilitate efficient host–bacteria interactions. Universally, BC aids in attachment, adherence, and subsequent colonization of a substrate. Bi-directional interactions influence host physiology, bacterial physiology, and regulation of BC biosynthesis, primarily through modulation of intracellular bis-(3′→5′)-cyclic diguanylate (c-di-GMP) levels. Depending on the circumstance, BC producers exhibit a pathogenic or symbiotic relationship with plant, animal, or fungal hosts. Rhizobiaceae species colonize plant roots, Pseudomonadaceae inhabit the phyllosphere, Acetobacteriaceae associate with sugar-loving insects and inhabit the carposphere, Enterobacteriaceae use fresh produce as vehicles to infect animal hosts, and Vibrionaceae, particularly Aliivibrio fischeri, colonize the light organ of squid. This review will highlight the diversity of the biosynthesis and regulation of BC in nature by discussing various examples of Proteobacteria that use BC-containing biofilms to facilitate host–bacteria interactions. Through discussion of current data we will establish new directions for the elucidation of BC biosynthesis, its regulation and its ecophysiological roles. PMID:26635751
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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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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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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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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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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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Chino, T; Nukui, Y; Morishita, Y; Moriya, K
2017-01-01
The bactericidal effect of disinfectants against biofilms is essential to reduce potential endoscopy-related infections caused by contamination. Here, we investigated the bactericidal effect of a high-level disinfectant, peracetic acid (PAA), against Staphylococcus aureus and Pseudomonas aeruginosa biofilm models in vitro. S. aureus and P. aeruginosa biofilms were cultured at 35 °C for 7 days with catheter tubes. The following high-level disinfectants (HLDs) were tested: 0.3% PAA, 0.55% ortho-phthalaldehyde (OPA), and 2.0% alkaline-buffered glutaraldehyde (GA). Biofilms were exposed to these agents for 1-60 min and observed after 5 min and 30 min by transmission and scanning electron microscopy. A Student's t test was performed to compare the exposure time required for bactericidal effectiveness of the disinfectants. PAA and GA were active within 1 min and 5 min, respectively, against S. aureus and P. aeruginosa biofilms. OPA took longer than 10 min and 30 min to act against S. aureus and P. aeruginosa biofilms, respectively ( p < 0.01). Treatment with PAA elicited changes in cell shape after 5 min and structural damage after 30 min. Amongst the HLDs investigated, PAA elicited the most rapid bactericidal effects against both biofilms. Additionally, treatment with PAA induced morphological alterations in the in vitro biofilm models, suggesting that PAA exerts fast-acting bactericidal effects against biofilms associated with endoscopy-related infections. These findings indicate that the exposure time for bactericidal effectiveness of HLDs for endoscope reprocessing in healthcare settings should be reconsidered.
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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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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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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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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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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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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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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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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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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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Yu, Haining; Liu, Xuelian; Wang, Chen; Qiao, Xue; Wu, Sijin; Wang, Hui; Feng, Lan; Wang, Yipeng
2016-02-01
As the most common fungal pathogen of humans, severe drug resistance has emerged in the clinically isolated Candida albicans, which lead to the urgency to develop novel antifungal agents. Here, four our previously characterized cathelicidins (cathelicidin-BF, Pc-CATH1, Cc-CATH2, Cc-CATH3) were selected and their antifungal activities against C. albicans were evaluated in vitro and in vivo using amphotericin B and LL-37 as control. Results showed that all four cathelicidins could eradicate standard and clinically isolated C. albicans strains with most MIC values ranging from 1 to 16 μg/ml, in less than 0.5 h revealed by time-kill kinetic assay. Four peptides only exhibited slight hemolytic activity with most HC50 > 200 μg/ml, and retained potent anti-C. albicans activity at salt concentrations below and beyond physiological level. In animal experiment, 50 mg/kg administration of the four cathelicidins could significantly reduce the fungal counts in a murine oral candidiasis model induced by clinically isolated C. albicans. The antibiofilm activity of cathelicidin-BF, the most potent among the five peptides was evaluated, and result showed that cathelicidin-BF strongly inhibited C. albicans biofilm formation at 20 μg/ml. Furthermore, cathelicidin-BF also exhibited potent anti-C. albicans activity in established biofilms as measured by metabolic and fluorescent viability assays. Structure-function analyses suggest that they mainly adopt an α-helical conformations, which enable them to act as a membrane-active molecule. Altogether, the four cathelicidins display great potential for antifungal agent development against candidiasis. Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.
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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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Xu, Wei; Zhu, Xin; Tan, Tingting; Li, Weizhong; Shan, Anshan
2014-01-01
Antimicrobial peptides have attracted considerable attention because of their broad-spectrum antimicrobial activity and their low prognostic to induce antibiotic resistance which is the most common source of failure in bacterial infection treatment along with biofilms. The method to design hybrid peptide integrating different functional domains of peptides has many advantages. In this study, we designed an embedded-hybrid peptide R-FV-I16 by replacing a functional defective sequence RR7 with the anti-biofilm sequence FV7 embedded in the middle position of peptide RI16. The results demonstrated that the synthetic hybrid the peptide R-FV-I16 had potent antimicrobial activity over a wide range of Gram-negative and Gram-positive bacteria, as well as anti-biofilm activity. More importantly, R-FV-I16 showed lower hemolytic activity and cytotoxicity. Fluorescent assays demonstrated that R-FV-I16 depolarized the outer and the inner bacterial membranes, while scanning electron microscopy and transmission electron microscopy further indicated that this peptide killed bacterial cells by disrupting the cell membrane, thereby damaging membrane integrity. Results from SEM also provided evidence that R-FV-I16 inherited anti-biofilm activity from the functional peptide sequence FV7. Embedded-hybrid peptides could provide a new pattern for combining different functional domains and showing an effective avenue to screen for novel antimicrobial agents. PMID:24945359
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Phototrophic microorganisms in biofilm samples from Vernjika Cave, Serbia
NASA Astrophysics Data System (ADS)
Popović, Slađana; Jovanović, Jelena; Predojević, Dragana; Trbojević, Ivana; Blagojević, Ana; Subakov Simić, Gordana
2016-04-01
Caves represent specific natural monuments in terms of structure, complexity and beauty which can be found worldwide. Even though they are considered extreme environments, they are still a unique habitat for a large number of organisms that grow and proliferate here. Often can be seen that the cave walls are differently coloured as a consequence of the biofilm development. Biofilms represent complex communities of microorganisms that can develop on different kind of surfaces, including various rock surfaces. Each microbe species play a different role in a community, but their development on stone surfaces can cause substantial damage to the substrates through different mechanisms of biodeterioration and degradation. There is an increased interest in the phototrophic component of biofilms (aerophytic cyanobacteria and algae), especially cyanobacteria, an ancient microorganisms capable to survive the most diverse extreme conditions. These phototrophs can easily be found at cave entrances illuminated by direct or indirect sunlight and areas near artificial lights. Cyanobacteria and algae were investigated in biofilm samples taken from the entrance of Vernjika Cave in Eastern Serbia. Cyanobacteria, Chlorophyta and Bacillariophyta were documented, with Cyanobacteria as a group with the highest number of recorded taxa. Chroococcalean species were the most diverse with the most frequently encountered species from the genus Gloeocapsa. Phormidium and Nostoc species were commonly recorded Oscillatoriales and Nostocles, respectively. Among Oscillatoriales species, it was noticed that one Phormidium species precipitates CaCO3 on it's sheats. Trebouxia sp. and Desmococcus olivaceus were frequently documented Chlorophyta, and representatives of Bacillariophyta were exclusively aerophytic taxa, mostly belonging to the genera Luticola and Humidophila. Measured ecological parameters, temperature and relative humidity, were influenced by the external climatic changes, while light
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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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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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... Skin Infections Overview of Fungal Skin Infections Candidiasis (Yeast Infection) Dermatophytid Reaction Intertrigo Tinea Versicolor Overview of ... breasts. Common fungal skin infections are caused by yeasts (such as Candida or Malassezia furfur ) or dermatophytes , ...
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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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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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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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Turonova, Hana; Briandet, Romain; Rodrigues, Ramila; Hernould, Mathieu; Hayek, Nabil; Stintzi, Alain; Pazlarova, Jarmila; Tresse, Odile
2015-01-01
During the last years, Campylobacter has emerged as the leading cause of bacterial foodborne infections in developed countries. Described as an obligate microaerophile, Campylobacter has puzzled scientists by surviving a wide range of environmental oxidative stresses on foods farm to retail, and thereafter intestinal transit and oxidative damage from macrophages to cause human infection. In this study, confocal laser scanning microscopy (CLSM) was used to explore the biofilm development of two well-described Campylobacter jejuni strains (NCTC 11168 and 81-176) prior to or during cultivation under oxygen-enriched conditions. Quantitative and qualitative appraisal indicated that C. jejuni formed finger-like biofilm structures with an open ultrastructure for 81-176 and a multilayer-like structure for NCTC 11168 under microaerobic conditions (MAC). The presence of motile cells within the biofilm confirmed the maturation of the C. jejuni 81-176 biofilm. Acclimation of cells to oxygen-enriched conditions led to significant enhancement of biofilm formation during the early stages of the process. Exposure to these conditions during biofilm cultivation induced an even greater biofilm development for both strains, indicating that oxygen demand for biofilm formation is higher than for planktonic growth counterparts. Overexpression of cosR in the poorer biofilm-forming strain, NCTC 11168, enhanced biofilm development dramatically by promoting an open ultrastructure similar to that observed for 81-176. Consequently, the regulator CosR is likely to be a key protein in the maturation of C. jejuni biofilm, although it is not linked to oxygen stimulation. These unexpected data advocate challenging studies by reconsidering the paradigm of fastidious requirements for C. jejuni growth when various subpopulations (from quiescent to motile cells) coexist in biofilms. These findings constitute a clear example of a survival strategy used by this emerging human pathogen.
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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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Wonoputri, Vita; Gunawan, Cindy; Liu, Sanly; Barraud, Nicolas; Yee, Lachlan H; Lim, May; Amal, Rose
2015-10-14
In this study, catalytic generation of nitric oxide by a copper(II) complex embedded within a poly(vinyl chloride) matrix in the presence of nitrite (source of nitric oxide) and ascorbic acid (reducing agent) was shown to effectively control the formation and dispersion of nitrifying bacteria biofilms. Amperometric measurements indicated increased and prolonged generation of nitric oxide with the addition of the copper complex when compared to that with nitrite and ascorbic acid alone. The effectiveness of the copper complex-nitrite-ascorbic acid system for biofilm control was quantified using protein analysis, which showed enhanced biofilm suppression when the copper complex was used in comparison to that with nitrite and ascorbic acid treatment alone. Confocal laser scanning microscopy (CLSM) and LIVE/DEAD staining revealed a reduction in cell surface coverage without a loss of viability with the copper complex and up to 5 mM of nitrite and ascorbic acid, suggesting that the nitric oxide generated from the system inhibits proliferation of the cells on surfaces. Induction of nitric oxide production by the copper complex system also triggered the dispersal of pre-established biofilms. However, the addition of a high concentration of nitrite and ascorbic acid to a pre-established biofilm induced bacterial membrane damage and strongly decreased the metabolic activity of planktonic and biofilm cells, as revealed by CLSM with LIVE/DEAD staining and intracellular adenosine triphosphate measurements, respectively. This study highlights the utility of the catalytic generation of nitric oxide for the long-term suppression and removal of nitrifying bacterial biofilms.
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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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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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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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Jung, Chiau-Jing; Hsu, Ron-Bin; Shun, Chia-Tung; Hsu, Chih-Chieh; Chia, Jean-San
2017-09-01
Host factors, such as platelets, have been shown to enhance biofilm formation by oral commensal streptococci, inducing infective endocarditis (IE), but how bacterial components contribute to biofilm formation in vivo is still not clear. We demonstrated previously that an isogenic mutant strain of Streptococcus mutans deficient in autolysin AtlA (Δ atlA ) showed a reduced ability to cause vegetation in a rat model of bacterial endocarditis. However, the role of AtlA in bacterial biofilm formation is unclear. In this study, confocal laser scanning microscopy analysis showed that extracellular DNA (eDNA) was embedded in S. mutans GS5 floes during biofilm formation on damaged heart valves, but an Δ atlA strain could not form bacterial aggregates. Semiquantification of eDNA by PCR with bacterial 16S rRNA primers demonstrated that the Δ atlA mutant strain produced dramatically less eDNA than the wild type. Similar results were observed with in vitro biofilm models. The addition of polyanethol sulfonate, a chemical lysis inhibitor, revealed that eDNA release mediated by bacterial cell lysis is required for biofilm initiation and maturation in the wild-type strain. Supplementation of cultures with calcium ions reduced wild-type growth but increased eDNA release and biofilm mass. The effect of calcium ions on biofilm formation was abolished in Δ atlA cultures and by the addition of polyanethol sulfonate. The VicK sensor, but not CiaH, was found to be required for the induction of eDNA release or the stimulation of biofilm formation by calcium ions. These data suggest that calcium ion-regulated AtlA maturation mediates the release of eDNA by S. mutans , which contributes to biofilm formation in infective endocarditis. Copyright © 2017 American Society for Microbiology.
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Hsu, Ron-Bin; Shun, Chia-Tung; Hsu, Chih-Chieh
2017-01-01
ABSTRACT Host factors, such as platelets, have been shown to enhance biofilm formation by oral commensal streptococci, inducing infective endocarditis (IE), but how bacterial components contribute to biofilm formation in vivo is still not clear. We demonstrated previously that an isogenic mutant strain of Streptococcus mutans deficient in autolysin AtlA (ΔatlA) showed a reduced ability to cause vegetation in a rat model of bacterial endocarditis. However, the role of AtlA in bacterial biofilm formation is unclear. In this study, confocal laser scanning microscopy analysis showed that extracellular DNA (eDNA) was embedded in S. mutans GS5 floes during biofilm formation on damaged heart valves, but an ΔatlA strain could not form bacterial aggregates. Semiquantification of eDNA by PCR with bacterial 16S rRNA primers demonstrated that the ΔatlA mutant strain produced dramatically less eDNA than the wild type. Similar results were observed with in vitro biofilm models. The addition of polyanethol sulfonate, a chemical lysis inhibitor, revealed that eDNA release mediated by bacterial cell lysis is required for biofilm initiation and maturation in the wild-type strain. Supplementation of cultures with calcium ions reduced wild-type growth but increased eDNA release and biofilm mass. The effect of calcium ions on biofilm formation was abolished in ΔatlA cultures and by the addition of polyanethol sulfonate. The VicK sensor, but not CiaH, was found to be required for the induction of eDNA release or the stimulation of biofilm formation by calcium ions. These data suggest that calcium ion-regulated AtlA maturation mediates the release of eDNA by S. mutans, which contributes to biofilm formation in infective endocarditis. PMID:28674029
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Metabolism in Fungal Pathogenesis
Ene, Iuliana V.; Brunke, Sascha; Brown, Alistair J.P.; Hube, Bernhard
2014-01-01
Fungal pathogens must assimilate local nutrients to establish an infection in their mammalian host. We focus on carbon, nitrogen, and micronutrient assimilation mechanisms, discussing how these influence host–fungus interactions during infection. We highlight several emerging trends based on the available data. First, the perturbation of carbon, nitrogen, or micronutrient assimilation attenuates fungal pathogenicity. Second, the contrasting evolutionary pressures exerted on facultative versus obligatory pathogens have led to contemporary pathogenic fungal species that display differing degrees of metabolic flexibility. The evolutionarily ancient metabolic pathways are conserved in most fungal pathogen, but interesting gaps exist in some species (e.g., Candida glabrata). Third, metabolic flexibility is generally essential for fungal pathogenicity, and in particular, for the adaptation to contrasting host microenvironments such as the gastrointestinal tract, mucosal surfaces, bloodstream, and internal organs. Fourth, this metabolic flexibility relies on complex regulatory networks, some of which are conserved across lineages, whereas others have undergone significant evolutionary rewiring. Fifth, metabolic adaptation affects fungal susceptibility to antifungal drugs and also presents exciting opportunities for the development of novel therapies. PMID:25190251
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Nielsen, M S; Frisvad, J C; Nielsen, P V
1998-06-30
The influence of fungal starter cultures on growth and secondary metabolite production of fungal contaminants associated with cheese was studied on laboratory media and Camembert cheese. Isolates of the species Penicillium nalgiovense, P. camemberti, P. roqueforti and Geotrichum candidum were used as fungal starters. The species P. commune, P. caseifulvum, P. verrucosum, P. discolor, P. solitum, P. coprophilum and Aspergillus versicolor were selected as contaminants. The fungal starters showed different competitive ability on laboratory media and Camembert cheese. The presence of the Penicillium species, especially P. nalgiovense, showed an inhibitory effect on the growth of the fungal contaminants on laboratory media. G. candidum caused a significant inhibition of the fungal contaminants on Camembert cheese. The results indicate that G. candidum plays an important role in competition with undesirable microorganisms in mould fermented cheeses. Among the starters, P. nalgiovense caused the largest reduction in secondary metabolite production of the fungal contaminants on the laboratory medium. On Camembert cheese no significant changes in metabolite production of the fungal contaminants was observed in the presence of the starters.
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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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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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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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Kim, Jun Young; Kwon, Hyuk Woo; Yun, Yeo Hong; Kim, Seong Hwan
2016-05-28
The shiitake mushroom industry has suffered from Camptomyia (gall midges) pest, which feeds on the mycelium of shiitake mushroom during its cultivation. It has been postulated that fungal damage of shiitake bed-logs is associated with infestation by the insect pest, but this is not well understood. To understand the fungal damage associated with Camptomyia pest, various Trichoderma species were isolated, identified, and characterized. In addition to two previously known Trichoderma species, T. citrinoviride and T. deliquescens, two other Trichoderma species, T. harzianum and T. atroviride, were newly identified from the pestinfested bed-log samples obtained at three mushroom farms in Cheonan, Korea. Among these four species, T. harzianum was the most evident. The results of a chromogenic media-based assay for extracellular enzymes showed that these four species have the ability to produce amylase, carboxyl-methyl cellulase, avicelase, pectinase, and β-glucosidase, thus indicating that they can degrade wood components. A dual culture assay on PDA indicated that T. harzianum, T. atroviride, and T. citrinoviride were antagonistic against the mycelial growth of a shiitake strain (Lentinula edodes). Inoculation tests on shiitake bed-logs revealed that all four species were able to damage the wood of bed-logs. Our results provide evidence that the four green mold species are the causal agents involved in fungal damage of shiitake bed-logs infested by Camptomyia pest.
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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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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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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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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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USDA-ARS?s Scientific Manuscript database
Foliar diseases and stalk rots are among the most damaging diseases of sorghum in terms of lost production potential, thus commanding considerable research time and expenditure. This review will focus on anthracnose, a fungal disease that causes both foliar symptoms and stalk rots along with the st...
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Findley, Keisha; Oh, Julia; Yang, Joy; Conlan, Sean; Deming, Clayton; Meyer, Jennifer A.; Schoenfeld, Deborah; Nomicos, Effie; Park, Morgan; Kong, Heidi H.; Segre, Julia A.
2013-01-01
Traditional culture-based methods have incompletely defined the etiology of common recalcitrant human fungal skin diseases including athlete’s foot and toenail infections. Skin protects humans from invasion by pathogenic microorganisms, while providing a home for diverse commensal microbiota1. Bacterial genomic sequence data have generated novel hypotheses about species and community structures underlying human disorders2,3,4. However, microbial diversity is not limited to bacteria; microorganisms such as fungi also play major roles in microbial community stability, human health and disease5. Genomic methodologies to identify fungal species and communities have been limited compared with tools available for bacteria6. Fungal evolution can be reconstructed with phylogenetic markers, including ribosomal RNA gene regions and other highly conserved genes7. Here, we sequenced and analyzed fungal communities of 14 skin sites in 10 healthy adults. Eleven core body and arm sites were dominated by Malassezia fungi, with species-level classifications revealing greater topographical resolution between sites. By contrast, three foot sites, plantar heel, toenail, and toeweb, exhibited tremendous fungal diversity. Concurrent analysis of bacterial and fungal communities demonstrated that skin physiologic attributes and topography differentially shape these two microbial communities. These results provide a framework for future investigation of interactions between pathogenic and commensal fungal and bacterial communities in maintaining human health and contributing to disease pathogenesis. PMID:23698366
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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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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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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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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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Das, Theerthankar; Simone, Martin; Ibugo, Amaye I.; Witting, Paul K.; Manefield, Mike; Manos, Jim
2017-01-01
Pyocyanin secreted by Pseudomonas aeruginosa is a virulence factor that damages epithelial cells during infection through the action of reactive oxygen species, however, little is known about its direct effect on biofilms. We demonstrated that pyocyanin-producing P. aeruginosa strains (PA14WT, DKN370, AES-1R, and AES-2) formed robust biofilms in contrast to the poorly formed biofilms of the pyocyanin mutant PA14ΔphzA-G and the low pyocyanin producer AES-1M. Addition of DNase I and reduced glutathione (GSH) significantly reduced biofilm biomass of pyocyanin-producing strains (P < 0.05) compared to non-pyocyanin producers. Subsequently we showed that a combined treatment comprising: GSH + DNase I + antibiotic, disrupted and reduced biofilm biomass up to 90% in cystic fibrosis isolates AES-1R, AES-2, LESB58, and LES431 and promoted lung epithelial cell (A549) recovery and growth. We also showed that exogenously added GSH restored A549 epithelial cell glutathione reductase activity in the presence of pyocyanin through recycling of GSSG to GSH and consequently increased total intracellular GSH levels, inhibiting oxidative stress, and facilitating cell growth and confluence. These outcomes indicate that GSH has multiple roles in facilitating a return to normal epithelial cell growth after insult by pyocyanin. With increased antibiotic resistance in many bacterial species, there is an urgency to establish novel antimicrobial agents. GSH is able to rapidly and comprehensively destroy P. aeruginosa associated biofilms while at a same time assisting in the recovery of host cells and re-growth of damaged tissue. PMID:29312161
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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