The Experts below are selected from a list of 27666 Experts worldwide ranked by ideXlab platform
Karine Vallée-réhel - One of the best experts on this subject based on the ideXlab platform.
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Formulation and antifouling activity of marine paints: a study by a statistically based experiments plan
Progress in Organic Coatings, 2002Co-Authors: Muriel Thouvenin, Jean Jacques Peron, J Y Langlois, Valerie Langlois, Philippe Guérin, Karine Vallée-réhelAbstract:To produce the new generation of protective marine paints with reduced amount of Biocides, it is necessary to understand the phenomenon of the antifouling activity. It would require to define all the mechanisms which are involved (diffusion of water and Biocides in the matrix, hydrolytic degradation of the matrix), the resulting properties (erosion, presence of Biocides), the influential factors (formulation, nature of the binder) and the links between factors and properties, which is totally unrealisable. In a first step, the antifouling activity is tackled by considering only three selected properties which are essential for the consumers: the toughness, the erosion and the release of Biocides. A statistically based experiments plan is established in order to progress systematically in the study of the properties of antifouling paints and to define the influential factors on antifouling activity. The obtained results enabled us to exhibit two discriminating factors: the nature of the binder and the biocide. The amount of released Biocides is largely inferior to the lethal doses for bacteria. These results lead to ask new questions about the antifouling activity and to produce efficient paints with restricted amounts of Biocides.
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Formulation and antifouling activity of marine paints: A study by a statistically based experiments plan
Progress in Organic Coatings, 2002Co-Authors: Muriel Thouvenin, Jean Jacques Peron, J Y Langlois, Ph. Guérin, Valerie Langlois, Karine Vallée-réhelAbstract:To produce the new generation of protective marine paints with reduced amount of Biocides, it is necessary to understand the phenomenon of the antifouling activity. It would require to define all the mechanisms which are involved (diffusion of water and Biocides in the matrix, hydrolytic degradation of the matrix), the resulting properties (erosion, presence of Biocides), the influential factors (formulation, nature of the binder) and the links between factors and properties, which is totally unrealisable. In a first step, the antifouling activity is tackled by considering only three selected properties which are essential for the consumers: the toughness, the erosion and the release of Biocides. A statistically based experiments plan is established in order to progress systematically in the study of the properties of antifouling paints and to define the influential factors on antifouling activity. The obtained results enabled us to exhibit two discriminating factors: the nature of the binder and the biocide. The amount of released Biocides is largely inferior to the lethal doses for bacteria. These results lead to ask new questions about the antifouling activity and to produce efficient paints with restricted amounts of Biocides. © 2002 Elsevier Science B.V. All rights reserved.
Jean-yves Maillard - One of the best experts on this subject based on the ideXlab platform.
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Resistance of Bacteria to Biocides
Microbiology spectrum, 2018Co-Authors: Jean-yves MaillardAbstract:Biocides and formulated Biocides are used worldwide for an increasing number of applications despite tightening regulations in Europe and in the United States. One concern is that such intense usage of Biocides could lead to increased bacterial resistance to a product and cross-resistance to unrelated antimicrobials including chemotherapeutic antibiotics. Evidence to justify such a concern comes mostly from the use of health care-relevant bacterial isolates, although the number of studies of the resistance characteristics of veterinary isolates to Biocides have increased the past few years. One problem remains the definition of “resistance” and how to measure resistance to a biocide. This has yet to be addressed globally, although the measurement of resistance is becoming more pressing, with regulators both in Europe and in the United States demanding that manufacturers provide evidence that their biocidal products will not impact on bacterial resistance. Alongside in vitro evidence of potential antimicrobial cross-resistance following biocide exposure, our understanding of the mechanisms of bacterial resistance and, more recently, our understanding of the effect of Biocides to induce a mechanism(s) of resistance in bacteria has improved. This article aims to provide an understanding of the development of antimicrobial resistance in bacteria following a biocide exposure. The sections provide evidence of the occurrence of bacterial resistance and its mechanisms of action and debate how to measure bacterial resistance to Biocides. Examples pertinent to the veterinary field are used where appropriate.
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bacterial resistance to Biocides in the healthcare environment should it be of genuine concern
Journal of Hospital Infection, 2007Co-Authors: Jean-yves MaillardAbstract:Summary The emergence of bacterial resistance following exposure in healthcare facilities has been a recurrent topic of interest over the last 10 years. The overwhelming and increasing body of evidence from studies in vitro showed that bacteria have an immense capacity to respond to chemical stress brought upon by Biocides. Empirically two major types of mechanisms have been described: intrinsic and acquired. However, the increasing documented response from bacteria exposed to biocide in conditions close to those found in practice suggests that intrinsic resistance does not adequately describe bacterial survival mechanisms, and that other terms such as biofilm resistance and environmental resistance would be therefore more appropriate. In addition, such terms are more relevant when describing in-situ conditions. The lack of evidence of bacterial resistance in practice and the inability to correlate emerging bacterial resistance from in-vitro experiments with practical situations is a major drawback when attempting to ascertain whether emerging bacterial resistance in healthcare facilities is of genuine concern. Microbial resistance to high or in-use concentration of Biocides has been described in practice, although it remains uncommon. The efficacy of Biocides in eliminating bacterial contaminants within healthcare facilities has to be questioned with the widespread and increasing use of products containing low concentrations of biocide or possessing low bactericidal activity, as is the selection of less susceptible bacteria following such exposure.
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bacterial target sites for biocide action
Journal of Applied Microbiology, 2002Co-Authors: Jean-yves MaillardAbstract:Although Biocides have been used for a century, the number of products containing Biocides has recently increased dramatically with public awareness of hygiene issues. The antimicrobial efficacy of Biocides is now well documented; however, there is still a lack of understanding of their antimicrobial mechanisms of action. There is a wide range of Biocides showing different levels of antimicrobial activity. It is generally accepted that, in contrast to chemotherapeutic agents, Biocides have multiple target sites within the microbial cell and the overall damage to these target sites results in the bactericidal effect. Information about the antimicrobial efficacy of a biocide (i.e. the eta-value) might give some useful indications about the overall mode of action of a biocide. Bacteriostatic effects, usually achieved by a lower concentration of a biocide, might correspond to a reversible activity on the cytoplasmic membrane and/or the impairment of enzymatic activity. The bacteriostatic mechanism(s) of action of a biocide is less documented and a primary (unique?) target site within the cell might be involved. Understanding the mechanism(s) of action of a biocide has become an important issue with the emergence of bacterial resistance to Biocides and the suggestion that biocide and antibiotic resistance in bacteria might be linked. There is still a lack of understanding of the mode of action of Biocides, especially when used at low concentrations (i.e. minimal inhibitory concentration (MIC) or sublethal). Although this information might not be required for highly reactive Biocides (e.g. alkylating and oxidizing agents) and Biocides used at high concentrations, the use of Biocides as preservatives or in products at sublethal concentrations, in which a bacteriostatic rather than a bactericidal activity is achieved, is driving the need to better understand microbial target sites. Understanding the mechanisms of action of Biocides serves several purposes: (i) it will help to design antimicrobial formulations with an improved antimicrobial efficacy and (ii) it will ensure the prevention of the emergence of microbial resistance.
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Virus susceptibility to Biocides: an understanding
Reviews in Medical Microbiology, 2001Co-Authors: Jean-yves MaillardAbstract:The term ‘biocide’ is widely used to denote a chemical agent that possesses antiseptic, disinfectant or preservative activity. Viruses are not the most resistant microorganisms to Biocides and it is generally accepted that the presence or absence of a lipid envelope and virus size play a important r
Muriel Thouvenin - One of the best experts on this subject based on the ideXlab platform.
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Formulation and antifouling activity of marine paints: a study by a statistically based experiments plan
Progress in Organic Coatings, 2002Co-Authors: Muriel Thouvenin, Jean Jacques Peron, J Y Langlois, Valerie Langlois, Philippe Guérin, Karine Vallée-réhelAbstract:To produce the new generation of protective marine paints with reduced amount of Biocides, it is necessary to understand the phenomenon of the antifouling activity. It would require to define all the mechanisms which are involved (diffusion of water and Biocides in the matrix, hydrolytic degradation of the matrix), the resulting properties (erosion, presence of Biocides), the influential factors (formulation, nature of the binder) and the links between factors and properties, which is totally unrealisable. In a first step, the antifouling activity is tackled by considering only three selected properties which are essential for the consumers: the toughness, the erosion and the release of Biocides. A statistically based experiments plan is established in order to progress systematically in the study of the properties of antifouling paints and to define the influential factors on antifouling activity. The obtained results enabled us to exhibit two discriminating factors: the nature of the binder and the biocide. The amount of released Biocides is largely inferior to the lethal doses for bacteria. These results lead to ask new questions about the antifouling activity and to produce efficient paints with restricted amounts of Biocides.
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Formulation and antifouling activity of marine paints: A study by a statistically based experiments plan
Progress in Organic Coatings, 2002Co-Authors: Muriel Thouvenin, Jean Jacques Peron, J Y Langlois, Ph. Guérin, Valerie Langlois, Karine Vallée-réhelAbstract:To produce the new generation of protective marine paints with reduced amount of Biocides, it is necessary to understand the phenomenon of the antifouling activity. It would require to define all the mechanisms which are involved (diffusion of water and Biocides in the matrix, hydrolytic degradation of the matrix), the resulting properties (erosion, presence of Biocides), the influential factors (formulation, nature of the binder) and the links between factors and properties, which is totally unrealisable. In a first step, the antifouling activity is tackled by considering only three selected properties which are essential for the consumers: the toughness, the erosion and the release of Biocides. A statistically based experiments plan is established in order to progress systematically in the study of the properties of antifouling paints and to define the influential factors on antifouling activity. The obtained results enabled us to exhibit two discriminating factors: the nature of the binder and the biocide. The amount of released Biocides is largely inferior to the lethal doses for bacteria. These results lead to ask new questions about the antifouling activity and to produce efficient paints with restricted amounts of Biocides. © 2002 Elsevier Science B.V. All rights reserved.
José L. Martínez - One of the best experts on this subject based on the ideXlab platform.
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multiple adaptive routes of salmonella enterica typhimurium to biocide and antibiotic exposure
BMC Genomics, 2016Co-Authors: Tânia Curiao, Denis Grandgirard, Ricardo Leonsampedro, Susan L. Leib, Marco R. Oggioni, Emmanuela Marchi, Fernando Baquero, Carlo Viti, José L. MartínezAbstract:Biocides and antibiotics are used to eradicate or prevent the growth of microbial species on surfaces (occasionally on catheters), or infected sites, either in combination or sequentially, raising concerns about the development of co-resistance to both antimicrobial types. The effect of such compounds on Salmonella enterica, a major food-borne and zoonotic pathogen, has been analysed in different studies, but only few works evaluated its biological cost, and the overall effects at the genomic and transcriptomic levels associated with diverse phenotypes resulting from biocide exposure, which was the aim of this work. Exposure to triclosan, clorhexidine, benzalkonium, (but not to hypochlorite) resulted in mutants with different phenotypes to a wide range of antimicrobials even unrelated to the selective agent. Most biocide-resistant mutants showed increased susceptibility to compounds acting on the cell wall (β-lactams) or the cell membranes (poly-L-lysine, polymyxin B, colistin or toxic anions). Mutations (SNPs) were found in three intergenic regions and nine genes, which have a role in energy production, amino acids, carbohydrates or lipids metabolism, some of them involved in membrane transport and pathogenicity. Comparative transcriptomics of biocide-resistant mutants showed over-expression of genes encoding efflux pumps (sugE), ribosomal and transcription-related proteins, cold-shock response (cpeE) and enzymes of microaerobic metabolism including those of the phosphotransferase system. Mainly ribosomal, metabolic and pathogenicity-related genes had affected expression in both in vitro-selected biocide mutants and field Salmonella isolates with reduced biocide susceptibility. Multiple pathways can be involved in the adaptation of Salmonella to Biocides, mainly related with global stress, or involving metabolic and membrane alterations, and eventually causing “collateral sensitivity” to other antimicrobials. These changes might impact the bacterial-environment interaction, imposing significant bacterial fitness costs which may reduce the chances of fixation and spread of biocide resistant mutants.
Mark Webber - One of the best experts on this subject based on the ideXlab platform.
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parallel evolutionary pathways to antibiotic resistance selected by biocide exposure
Journal of Antimicrobial Chemotherapy, 2015Co-Authors: Mark Webber, Manuella Mount, Rebekah N. Whitehead, Nicholas J Loman, Mark J. Pallen, Laura J V PiddockAbstract:OBJECTIVES: Biocides are widely used to prevent infection. We aimed to determine whether exposure of Salmonella to various Biocides could act as a driver of antibiotic resistance. METHODS: Salmonella enterica serovar Typhimurium was exposed to four Biocides with differing modes of action. Antibiotic-resistant mutants were selected during exposure to all Biocides and characterized phenotypically and genotypically to identify mechanisms of resistance. RESULTS: All Biocides tested selected MDR mutants with decreased antibiotic susceptibility; these occurred randomly throughout the experiments. Mutations that resulted in de-repression of the multidrug efflux pump AcrAB-TolC were seen in MDR mutants. A novel mutation in rpoA was also selected and contributed to the MDR phenotype. Other mutants were highly resistant to both quinolone antibiotics and the biocide triclosan. CONCLUSIONS: This study shows that exposure of bacteria to Biocides can select for antibiotic-resistant mutants and this is mediated by clinically relevant mechanisms of resistance prevalent in human pathogens.
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exposure of salmonella enterica serovar typhimurium to high level biocide challenge can select multidrug resistant mutants in a single step
PLOS ONE, 2011Co-Authors: Rebekah N. Whitehead, Caroline L Kemp, Timothy W Overton, Mark WebberAbstract:Background Biocides are crucial to the prevention of infection by bacteria, particularly with the global emergence of multiply antibiotic resistant strains of many species. Concern has been raised regarding the potential for biocide exposure to select for antibiotic resistance due to common mechanisms of resistance, notably efflux. Methodology/Principal Findings Salmonella enterica serovar Typhimurium was challenged with 4 Biocides of differing modes of action at both low and recommended-use concentration. Flow cytometry was used to investigate the physiological state of the cells after biocide challenge. After 5 hours exposure to biocide, live cells were sorted by FACS and recovered. Cells recovered after an exposure to low concentrations of biocide had antibiotic resistance profiles similar to wild-type cells. Live cells were recovered after exposure to two of the Biocides at in-use concentration for 5 hours. These cells were multi-drug resistant and accumulation assays demonstrated an efflux phenotype of these mutants. Gene expression analysis showed that the AcrEF multidrug efflux pump was de-repressed in mutants isolated from high-levels of biocide. Conclusions/Significance These data show that a single exposure to the working concentration of certain Biocides can select for mutant Salmonella with efflux mediated multidrug resistance and that flow cytometry is a sensitive tool for identifying biocide tolerant mutants. The propensity for Biocides to select for MDR mutants varies and this should be a consideration when designing new biocidal formulations.
