The Experts below are selected from a list of 10584 Experts worldwide ranked by ideXlab platform
Gideon M. Wolfaardt - One of the best experts on this subject based on the ideXlab platform.
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Biofilms' Role in Planktonic Cell Proliferation
International journal of molecular sciences, 2013Co-Authors: Elanna Bester, Gideon M. Wolfaardt, Nahid Babaei Aznaveh, Jesse GreenerAbstract:The detachment of single Cells from biofilms is an intrinsic part of this surface-associated mode of bacterial existence. Pseudomonas sp. strain CT07gfp biofilms, cultivated in microfluidic channels under continuous flow conditions, were subjected to a range of liquid shear stresses (9.42 mPa to 320 mPa). The number of detached Planktonic Cells was quantified from the effluent at 24-h intervals, while average biofilm thickness and biofilm surface area were determined by confocal laser scanning microscopy and image analysis. Biofilm accumulation proceeded at the highest applied shear stress, while similar rates of Planktonic Cell detachment was maintained for biofilms of the same age subjected to the range of average shear rates. The conventional view of liquid-mediated shear leading to the passive erosion of single Cells from the biofilm surface, disregards the active contribution of attached Cell metabolism and growth to the observed detachment rates. As a complement to the conventional conceptual biofilm models, the existence of a biofilm surface-associated zone of Planktonic Cell proliferation is proposed to highlight the need to expand the traditional perception of biofilms as promoting microbial survival, to include the potential of biofilms to contribute to microbial proliferation.
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Biofilm form and function: carbon availability affects biofilm architecture, metabolic activity and Planktonic Cell yield
Journal of applied microbiology, 2010Co-Authors: Elanna Bester, Otini Kroukamp, Martina Hausner, Elizabeth A. Edwards, Gideon M. WolfaardtAbstract:Aims: To investigate carbon transformation by biofilms and changes in biofilm architecture, metabolic activity and Planktonic Cell yield in response to fluctuating carbon availability. Methods and Results: Pseudomonas sp. biofilms were cultured under alternating carbon-replete and carbon-limited conditions. A shift to medium without added carbon led to a 90% decrease in biofilm respiration rate and a 40% reduction in Planktonic Cell yield within 1 h. Attached Cell division and progeny release were shown to contribute to Planktonic Cell numbers during carbon limitation. Development of a significantly enlarged biofilm surface area during carbon limitation facilitated a rapid increase in whole-biofilm metabolic activity, Cell yield and biomass upon the re-introduction of carbon after 8 days of limitation. The cumulative number of Planktonic Cells (>1010 CFU) released from the biofilm during the cultivation period contained only 1·0% of the total carbon available to the biofilm, with 6·5% of the carbon retained in the biofilm and 54% mineralized to CO2. Conclusions: Biofilm-derived Planktonic Cell yield is a proliferation mechanism. The rapid response of biofilms to environmental perturbations facilitates the optimal utilization of resources to promote both proliferation and survival. Biofilms function as efficient catalysts for environmental carbon transformation and mineralization. Significance and Impact of the study: A greater understanding of the relationship between biofilm form and function can inform strategies intended to control and/or promote biofilm formation.
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Pronounced Effect of the Nature of the Inoculum on Biofilm Development in Flow Systems
Applied and environmental microbiology, 2010Co-Authors: Otini Kroukamp, Romeo G. Dumitrache, Gideon M. WolfaardtAbstract:Biofilm formation renders sessile microbial populations growing in continuous-flow systems less susceptible to variation in dilution rate than Planktonic Cells, where dilution rates exceeding an organism's maximum growth rate (μmax) results in Planktonic Cell washout. In biofilm-dominated systems, the biofilm's overall μmax may therefore be more relevant than the organism's μmax, where the biofilm μmax is considered as a net process dependent on the adsorption rate, growth rate, and removal rate of Cells within the biofilm. Together with lag (acclimation) time, the biofilm's overall μmax is important wherever biofilm growth is a dominant form, from clinical settings, where the aim is to prevent transition from lag to exponential growth, to industrial bioreactors, where the aim is to shorten the lag and rapidly reach maximum activity. The purpose of this study was to measure CO2 production as an indicator of biofilm activity to determine the effect of nutrient type and concentration and of the origin of the inoculum on the length of the lag phase, biofilm μmax, and steady-state metabolic activity of Pseudomonas aeruginosa PA01 (containing gfp), Pseudomonas fluorescens CT07 (containing gfp), and a mixed community. As expected, for different microorganisms the lengths of the lag phase in biofilm development and the biofilm μmax values differ, whereas different nutrient concentrations result in differences in the lengths of lag phase and steady-state values but not in biofilm μmax rates. The data further showed that inocula from different phenotypic origins give rise to lag time of different lengths and that this influence persists for a number of generations after inoculation.
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Planktonic Cell yield is linked to biofilm development.
Canadian journal of microbiology, 2009Co-Authors: Elanna Bester, Elizabeth A. Edwards, Gideon M. WolfaardtAbstract:We report on the ability of surface-associated microbes to produce and release single Planktonic Cells to the bulk liquid as early as 6 h after attachment, with pure culture and mixed-species biofi...
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Planktonic Cell yield of a pseudomonad biofilm
Applied and Environmental Microbiology, 2005Co-Authors: Elanna Bester, Gideon M. Wolfaardt, Lydia Joubert, Kerstin Garny, Sanja SafticAbstract:Biofilm Cells differ phenotypically from their free-floating counterparts. Differential growth rates in biofilms are often referred to, particularly in response to limited diffusion of oxygen and nutrients. We observed growth rates of attached Pseudomonas sp. strain CT07 Cells that were notably higher than the maximum specific growth rate measured in batch culture. Despite dilution rates in continuous flow Cells that exceeded the maximum Planktonic specific growth rate by 58 times, sampling of the effluent revealed >109 Cells ml−1, suggesting that biofilms function as a source of Planktonic Cells through high Cell yield and detachment. Further investigation demonstrated considerable Planktonic Cell yield from biofilms as young as 6 h, indicating that detachment is not limited to established biofilms. These biofilm-detached Cells were more sensitive to a commercial biocide than associated biofilm- and chemostat-cultivated populations, implying that detached biofilm Cells exhibit a character that is distinct from that of attached and Planktonic Cell populations.
Paul Humphreys - One of the best experts on this subject based on the ideXlab platform.
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A systematic comparison of antimicrobial wound dressings using a Planktonic Cell and an immobilized Cell model
Journal of applied microbiology, 2015Co-Authors: Kamran Shoukat, Sally Pilling, Simon P. Rout, Jane Bradbury, Paul HumphreysAbstract:Aim: The aim of the study was to evaluate the ability of in-vitro Planktonic and immobilised Cell models for determining the antimicrobial efficacy of common antimicrobial wound dressings. Methods and Results: Five strains of A.baumannii , P.aeruginosa and S. aureus (MRSA) were tested against four antimicrobial wound dressings containing silver, honey or PHMB, using both a Planktonic and immobilised Cell model. Across all species and models used, the NSCD demonstrated the best antimicrobial activity being as good if not better than all the other dressings. The Planktonic Cell model was less effective at differentiating the dressings on antimicrobial performance as the immobilised Cell model indicating that a diffusion barrier had a significant impact on the performance of some dressings. In the presence of the diffusion barrier antimicrobial impact of the Honey and PHMB dressings was significantly reduced particularly in the case of A. baumannii. Activity was at least an order of magnitude lower in the immobilised Cell model vs. the Planktonic Cell model. Conclusions: The use of a Planktonic Cell model within standard tests may overestimate the efficacy of honey and PHMB. The use of an immobilised Cell model provides a more demanding test for antimicrobial dressings allowing dressing to dressing and pathogen to pathogen differences to be more clearly quantified. Significance and Impact of study: The introduction of Planktonic and immobilised Cell models as part of testing regimens for wound dressings will provide a more thorough understanding of their antimicrobial and antibiofilm properties.
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A systematic comparison of antimicrobial wound dressings using a Planktonic Cell and an immobilized Cell model
Journal of applied microbiology, 2015Co-Authors: Kamran Shoukat, Sally Pilling, Simon P. Rout, Jane Bradbury, Paul HumphreysAbstract:The aim of the study was to evaluate the ability of in vitro Planktonic and immobilized Cell models for determining the antimicrobial efficacy of common antimicrobial wound dressings. Five strains of Acinetobacter baumannii, Pseudomonas aeruginosa and methicillin resistant Staphylococcus aureus were tested against four antimicrobial wound dressings containing silver, honey or polyhexamethylene biguanide (PHMB), using both a Planktonic and immobilized Cell model. Across all species and models used, the nanocrystalline silver coated dressing demonstrated the best antimicrobial activity being as good if not better than all the other dressings. The Planktonic Cell model was less effective at differentiating the dressings on antimicrobial performance as the immobilized Cell model indicating that a diffusion barrier had a significant impact on the performance of some dressings. In the presence of the diffusion barrier, antimicrobial impact of the Honey and PHMB dressings was significantly reduced, particularly in the case of A. baumannii. Activity was at least an order of magnitude lower in the immobilized Cell model vs the Planktonic Cell model. The use of a Planktonic Cell model within standard tests may overestimate the efficacy of honey and PHMB. The use of an immobilized Cell model provides a more demanding test for antimicrobial dressings allowing dressing to dressing and pathogen to pathogen differences to be more clearly quantified. The introduction of Planktonic and immobilized Cell models as part of testing regimens for wound dressings will provide a more thorough understanding of their antimicrobial and anti-biofilm properties. © 2015 The Society for Applied Microbiology.
Elanna Bester - One of the best experts on this subject based on the ideXlab platform.
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Biofilms' Role in Planktonic Cell Proliferation
International journal of molecular sciences, 2013Co-Authors: Elanna Bester, Gideon M. Wolfaardt, Nahid Babaei Aznaveh, Jesse GreenerAbstract:The detachment of single Cells from biofilms is an intrinsic part of this surface-associated mode of bacterial existence. Pseudomonas sp. strain CT07gfp biofilms, cultivated in microfluidic channels under continuous flow conditions, were subjected to a range of liquid shear stresses (9.42 mPa to 320 mPa). The number of detached Planktonic Cells was quantified from the effluent at 24-h intervals, while average biofilm thickness and biofilm surface area were determined by confocal laser scanning microscopy and image analysis. Biofilm accumulation proceeded at the highest applied shear stress, while similar rates of Planktonic Cell detachment was maintained for biofilms of the same age subjected to the range of average shear rates. The conventional view of liquid-mediated shear leading to the passive erosion of single Cells from the biofilm surface, disregards the active contribution of attached Cell metabolism and growth to the observed detachment rates. As a complement to the conventional conceptual biofilm models, the existence of a biofilm surface-associated zone of Planktonic Cell proliferation is proposed to highlight the need to expand the traditional perception of biofilms as promoting microbial survival, to include the potential of biofilms to contribute to microbial proliferation.
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Biofilm form and function: carbon availability affects biofilm architecture, metabolic activity and Planktonic Cell yield
Journal of applied microbiology, 2010Co-Authors: Elanna Bester, Otini Kroukamp, Martina Hausner, Elizabeth A. Edwards, Gideon M. WolfaardtAbstract:Aims: To investigate carbon transformation by biofilms and changes in biofilm architecture, metabolic activity and Planktonic Cell yield in response to fluctuating carbon availability. Methods and Results: Pseudomonas sp. biofilms were cultured under alternating carbon-replete and carbon-limited conditions. A shift to medium without added carbon led to a 90% decrease in biofilm respiration rate and a 40% reduction in Planktonic Cell yield within 1 h. Attached Cell division and progeny release were shown to contribute to Planktonic Cell numbers during carbon limitation. Development of a significantly enlarged biofilm surface area during carbon limitation facilitated a rapid increase in whole-biofilm metabolic activity, Cell yield and biomass upon the re-introduction of carbon after 8 days of limitation. The cumulative number of Planktonic Cells (>1010 CFU) released from the biofilm during the cultivation period contained only 1·0% of the total carbon available to the biofilm, with 6·5% of the carbon retained in the biofilm and 54% mineralized to CO2. Conclusions: Biofilm-derived Planktonic Cell yield is a proliferation mechanism. The rapid response of biofilms to environmental perturbations facilitates the optimal utilization of resources to promote both proliferation and survival. Biofilms function as efficient catalysts for environmental carbon transformation and mineralization. Significance and Impact of the study: A greater understanding of the relationship between biofilm form and function can inform strategies intended to control and/or promote biofilm formation.
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Planktonic Cell yield is linked to biofilm development.
Canadian journal of microbiology, 2009Co-Authors: Elanna Bester, Elizabeth A. Edwards, Gideon M. WolfaardtAbstract:We report on the ability of surface-associated microbes to produce and release single Planktonic Cells to the bulk liquid as early as 6 h after attachment, with pure culture and mixed-species biofi...
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Planktonic Cell yield of a pseudomonad biofilm
Applied and Environmental Microbiology, 2005Co-Authors: Elanna Bester, Gideon M. Wolfaardt, Lydia Joubert, Kerstin Garny, Sanja SafticAbstract:Biofilm Cells differ phenotypically from their free-floating counterparts. Differential growth rates in biofilms are often referred to, particularly in response to limited diffusion of oxygen and nutrients. We observed growth rates of attached Pseudomonas sp. strain CT07 Cells that were notably higher than the maximum specific growth rate measured in batch culture. Despite dilution rates in continuous flow Cells that exceeded the maximum Planktonic specific growth rate by 58 times, sampling of the effluent revealed >109 Cells ml−1, suggesting that biofilms function as a source of Planktonic Cells through high Cell yield and detachment. Further investigation demonstrated considerable Planktonic Cell yield from biofilms as young as 6 h, indicating that detachment is not limited to established biofilms. These biofilm-detached Cells were more sensitive to a commercial biocide than associated biofilm- and chemostat-cultivated populations, implying that detached biofilm Cells exhibit a character that is distinct from that of attached and Planktonic Cell populations.
Raymond J Turner - One of the best experts on this subject based on the ideXlab platform.
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Multimetal resistance and tolerance in microbial biofilms
Nature Reviews Microbiology, 2007Co-Authors: Joe J Harrison, Howard Ceri, Raymond J TurnerAbstract:This Review focuses on the combined action of chemical, physical and physiological phenomena that protect biofilm microorganisms from toxic metal ions. This includes: metabolic heterogeneity that is introduced by community structure; interCellular signalling events that contribute to the biofilm lifestyle; metal-ion immobilization by biosorption; bioinorganic reactions of metal ions with microbial metabolites; adaptive stress responses; persister Cells; and genetic rearrangements or mutations that produce variant phenotypes. Different metal species have distinct chemistries and can poison Cells through multiple biochemical pathways. Correlations between susceptibility data and metal-ion physicochemical parameters suggest that chemical mechanisms of toxicity differ between Planktonic and biofilm Cells. The co-selection of genetic and biochemical pathways might be involved in multimetal and multidrug resistance and/or tolerance. The evidence reviewed here suggests that multimetal resistance (MMR) and tolerance (MMT) may be linked to phenotypic variation among Cells in the biofilm population. We propose a multifactorial model of biofilm MMR and MMT in which biofilms can withstand metal toxicity by a process of Cellular diversification that is ongoing within the microbial population. How is it that biofilms are less susceptible to metal toxicity than exponentially growing Planktonic Cell populations? Here, Harrison and colleagues propose a multifactorial model of biofilm multimetal resistance and tolerance by which biofilms can withstand metal toxicity by an ongoing process of Cellular diversification within the microbial population. Geochemical cycling and industrial pollution have made toxic metal ions a pervasive environmental pressure throughout the world. Biofilm formation is a strategy that microorganisms might use to survive a toxic flux in these inorganic compounds. Evidence in the literature suggests that biofilm populations are protected from toxic metals by the combined action of chemical, physical and physiological phenomena that are, in some instances, linked to phenotypic variation among the constituent biofilm Cells. Here, we propose a multifactorial model by which biofilm populations can withstand metal toxicity by a process of Cellular diversification.
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high throughput metal susceptibility testing of microbial biofilms
BMC Microbiology, 2005Co-Authors: Joe J Harrison, Raymond J Turner, Howard CeriAbstract:Microbial biofilms exist all over the natural world, a distribution that is paralleled by metal cations and oxyanions. Despite this reality, very few studies have examined how biofilms withstand exposure to these toxic compounds. This article describes a batch culture technique for biofilm and Planktonic Cell metal susceptibility testing using the MBEC assay. This device is compatible with standard 96-well microtiter plate technology. As part of this method, a two part, metal specific neutralization protocol is summarized. This procedure minimizes residual biological toxicity arising from the carry-over of metals from challenge to recovery media. Neutralization consists of treating cultures with a chemical compound known to react with or to chelate the metal. Treated cultures are plated onto rich agar to allow metal complexes to diffuse into the recovery medium while bacteria remain on top to recover. Two difficulties associated with metal susceptibility testing were the focus of two applications of this technique. First, assays were calibrated to allow comparisons of the susceptibility of different organisms to metals. Second, the effects of exposure time and growth medium composition on the susceptibility of E. coli JM109 biofilms to metals were investigated. This high-throughput method generated 96-statistically equivalent biofilms in a single device and thus allowed for comparative and combinatorial experiments of media, microbial strains, exposure times and metals. By adjusting growth conditions, it was possible to examine biofilms of different microorganisms that had similar Cell densities. In one example, Pseudomonas aeruginosa ATCC 27853 was up to 80 times more resistant to heavy metalloid oxyanions than Escherichia coli TG1. Further, biofilms were up to 133 times more tolerant to tellurite (TeO32-) than corresponding Planktonic cultures. Regardless of the growth medium, the tolerance of biofilm and Planktonic Cell E. coli JM109 to metals was time-dependent. This method results in accurate, easily reproducible comparisons between the susceptibility of Planktonic Cells and biofilms to metals. Further, it was possible to make direct comparisons of the ability of different microbial strains to withstand metal toxicity. The data presented here also indicate that exposure time is an important variable in metal susceptibility testing of bacteria.
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Differences in biofilm and Planktonic Cell mediated reduction of metalloid oxyanions.
Fems Microbiology Letters, 2004Co-Authors: Joe J Harrison, Howard Ceri, Carol A. Stremick, Raymond J TurnerAbstract:This study compares Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 27853 biofilm and Planktonic Cell susceptibility to the selenium and tellurium oxyanions selenite (SeO32−), tellurate (TeO42−), and tellurite (TeO32−). P. aeruginosa Planktonic and biofilm cultures reduced the selenium and tellurium oxyanions to orange and black end-products (respectively) and were equally tolerant to killing by these metalloid compounds. S. aureus Planktonic Cell cultures processed these metalloid oxyanions in a similar way, but the corresponding biofilm cultures did not. S. aureus biofilms were approximately two and five times more susceptible to killing by tellurate and tellurite (respectively) than the corresponding Planktonic cultures. Our data indicate that the means of reducing metalloid oxyanions may differ between the physiology displayed in biofilm and Planktonic cultures of the same bacterial strain.
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Biofilm susceptibility to metal toxicity
Environmental microbiology, 2004Co-Authors: Joe J Harrison, Howard Ceri, Carol A. Stremick, Raymond J TurnerAbstract:Summary This study compared bacterial biofilm and Planktonic Cell susceptibility to metal toxicity by evaluating the minimum inhibitory concentration (MIC), the Planktonic minimum bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC) using the MBEC™ device. In total, 17 metal cations and oxyanions, chosen to represent groups VIB to VIA of the periodic table, were each tested on biofilm and Planktonic cultures of Escherichia coli JM109, Staphylococcus aureus ATCC 29213, and Pseudomonas aeruginosa ATCC 27853. In contrast to control antibiotic assays, where biofilm cultures were 2 to 64 times less susceptible to killing than logarithmically growing Planktonic bacteria, metal compounds killed Planktonic and biofilm cultures at the same concentration in the vast majority of combinations. Our data indicate that, under the conditions reported, growth in a biofilm does not provide resistance to bacteria against killing by metal cations or oxyanions.
Howard Ceri - One of the best experts on this subject based on the ideXlab platform.
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Multimetal resistance and tolerance in microbial biofilms
Nature Reviews Microbiology, 2007Co-Authors: Joe J Harrison, Howard Ceri, Raymond J TurnerAbstract:This Review focuses on the combined action of chemical, physical and physiological phenomena that protect biofilm microorganisms from toxic metal ions. This includes: metabolic heterogeneity that is introduced by community structure; interCellular signalling events that contribute to the biofilm lifestyle; metal-ion immobilization by biosorption; bioinorganic reactions of metal ions with microbial metabolites; adaptive stress responses; persister Cells; and genetic rearrangements or mutations that produce variant phenotypes. Different metal species have distinct chemistries and can poison Cells through multiple biochemical pathways. Correlations between susceptibility data and metal-ion physicochemical parameters suggest that chemical mechanisms of toxicity differ between Planktonic and biofilm Cells. The co-selection of genetic and biochemical pathways might be involved in multimetal and multidrug resistance and/or tolerance. The evidence reviewed here suggests that multimetal resistance (MMR) and tolerance (MMT) may be linked to phenotypic variation among Cells in the biofilm population. We propose a multifactorial model of biofilm MMR and MMT in which biofilms can withstand metal toxicity by a process of Cellular diversification that is ongoing within the microbial population. How is it that biofilms are less susceptible to metal toxicity than exponentially growing Planktonic Cell populations? Here, Harrison and colleagues propose a multifactorial model of biofilm multimetal resistance and tolerance by which biofilms can withstand metal toxicity by an ongoing process of Cellular diversification within the microbial population. Geochemical cycling and industrial pollution have made toxic metal ions a pervasive environmental pressure throughout the world. Biofilm formation is a strategy that microorganisms might use to survive a toxic flux in these inorganic compounds. Evidence in the literature suggests that biofilm populations are protected from toxic metals by the combined action of chemical, physical and physiological phenomena that are, in some instances, linked to phenotypic variation among the constituent biofilm Cells. Here, we propose a multifactorial model by which biofilm populations can withstand metal toxicity by a process of Cellular diversification.
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high throughput metal susceptibility testing of microbial biofilms
BMC Microbiology, 2005Co-Authors: Joe J Harrison, Raymond J Turner, Howard CeriAbstract:Microbial biofilms exist all over the natural world, a distribution that is paralleled by metal cations and oxyanions. Despite this reality, very few studies have examined how biofilms withstand exposure to these toxic compounds. This article describes a batch culture technique for biofilm and Planktonic Cell metal susceptibility testing using the MBEC assay. This device is compatible with standard 96-well microtiter plate technology. As part of this method, a two part, metal specific neutralization protocol is summarized. This procedure minimizes residual biological toxicity arising from the carry-over of metals from challenge to recovery media. Neutralization consists of treating cultures with a chemical compound known to react with or to chelate the metal. Treated cultures are plated onto rich agar to allow metal complexes to diffuse into the recovery medium while bacteria remain on top to recover. Two difficulties associated with metal susceptibility testing were the focus of two applications of this technique. First, assays were calibrated to allow comparisons of the susceptibility of different organisms to metals. Second, the effects of exposure time and growth medium composition on the susceptibility of E. coli JM109 biofilms to metals were investigated. This high-throughput method generated 96-statistically equivalent biofilms in a single device and thus allowed for comparative and combinatorial experiments of media, microbial strains, exposure times and metals. By adjusting growth conditions, it was possible to examine biofilms of different microorganisms that had similar Cell densities. In one example, Pseudomonas aeruginosa ATCC 27853 was up to 80 times more resistant to heavy metalloid oxyanions than Escherichia coli TG1. Further, biofilms were up to 133 times more tolerant to tellurite (TeO32-) than corresponding Planktonic cultures. Regardless of the growth medium, the tolerance of biofilm and Planktonic Cell E. coli JM109 to metals was time-dependent. This method results in accurate, easily reproducible comparisons between the susceptibility of Planktonic Cells and biofilms to metals. Further, it was possible to make direct comparisons of the ability of different microbial strains to withstand metal toxicity. The data presented here also indicate that exposure time is an important variable in metal susceptibility testing of bacteria.
-
Differences in biofilm and Planktonic Cell mediated reduction of metalloid oxyanions.
Fems Microbiology Letters, 2004Co-Authors: Joe J Harrison, Howard Ceri, Carol A. Stremick, Raymond J TurnerAbstract:This study compares Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 27853 biofilm and Planktonic Cell susceptibility to the selenium and tellurium oxyanions selenite (SeO32−), tellurate (TeO42−), and tellurite (TeO32−). P. aeruginosa Planktonic and biofilm cultures reduced the selenium and tellurium oxyanions to orange and black end-products (respectively) and were equally tolerant to killing by these metalloid compounds. S. aureus Planktonic Cell cultures processed these metalloid oxyanions in a similar way, but the corresponding biofilm cultures did not. S. aureus biofilms were approximately two and five times more susceptible to killing by tellurate and tellurite (respectively) than the corresponding Planktonic cultures. Our data indicate that the means of reducing metalloid oxyanions may differ between the physiology displayed in biofilm and Planktonic cultures of the same bacterial strain.
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Biofilm susceptibility to metal toxicity
Environmental microbiology, 2004Co-Authors: Joe J Harrison, Howard Ceri, Carol A. Stremick, Raymond J TurnerAbstract:Summary This study compared bacterial biofilm and Planktonic Cell susceptibility to metal toxicity by evaluating the minimum inhibitory concentration (MIC), the Planktonic minimum bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC) using the MBEC™ device. In total, 17 metal cations and oxyanions, chosen to represent groups VIB to VIA of the periodic table, were each tested on biofilm and Planktonic cultures of Escherichia coli JM109, Staphylococcus aureus ATCC 29213, and Pseudomonas aeruginosa ATCC 27853. In contrast to control antibiotic assays, where biofilm cultures were 2 to 64 times less susceptible to killing than logarithmically growing Planktonic bacteria, metal compounds killed Planktonic and biofilm cultures at the same concentration in the vast majority of combinations. Our data indicate that, under the conditions reported, growth in a biofilm does not provide resistance to bacteria against killing by metal cations or oxyanions.