title: Proteomic and phenotypic analysis of triclosan tolerant verocytotoxigenic Escherichia coli O157:H19.
abstract: Triclosan is a biocidal active agent commonly used in domestic and industrial formulations. Currently, there is limited understanding of the mechanisms involved in triclosan tolerance in Escherichia coli O157. The aim of this study was to identify the differences between a triclosan susceptible E. coli O157:H19 isolate (minimum inhibitory concentration; MIC 6.25 μg/ml) and its triclosan tolerant mutant (MIC>8000 μg/ml) at a proteomic and phenotypic level. Two dimensional DIGE was used to identify differences in protein expression between the reference strain and triclosan tolerant mutant in the presence and absence of triclosan. DIGE analysis indicates the proteome of the reference E. coli O157:H19 was significantly different to its triclosan tolerant mutant. Significant changes in protein expression levels in the triclosan tolerant mutant included the known triclosan target FabI which encodes enoyl reductase, outer membrane proteins and the filament structural protein of flagella, FliC. Phenotypic studies showed that the triclosan tolerant mutant MIC decreased in the presence of efflux inhibitor phenyl-arginine-β-naphthylamide and biofilm formation was increased in the mutant strain. The data generated indicates that enhanced triclosan tolerance is a result of multiple mechanisms which act together to achieve high-level resistance, rather than mutation of FabI alone.
authors: Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland; UCD Centre for Food Safety & the Centre for Food-borne Zoonomics, School of Public Health, Physiotherapy & Population Sciences, Dublin, Ireland.
authors: A
authors: A
authors: Sheridan
authors: Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland.
authors: M
authors: M
authors: Lenahan
authors: Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland; UCD Centre for Food Safety & the Centre for Food-borne Zoonomics, School of Public Health, Physiotherapy & Population Sciences, Dublin, Ireland.
authors: O
authors: O
authors: Condell
authors: School of Veterinary Medicine, UCD, Dublin, Ireland.
authors: R
authors: R
authors: Bonilla-Santiago
authors: Centre de Recherche Public - Gabriel Lippmann, Department of Environment and Agrobiotechnologies (EVA) L-4422 Belvaux, Luxembourg.
authors: K
authors: K
authors: Sergeant
authors: Centre de Recherche Public - Gabriel Lippmann, Department of Environment and Agrobiotechnologies (EVA) L-4422 Belvaux, Luxembourg.
authors: J
authors: J
authors: Renaut
authors: Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland.
authors: G
authors: G
authors: Duffy
authors: UCD Centre for Food Safety & the Centre for Food-borne Zoonomics, School of Public Health, Physiotherapy & Population Sciences, Dublin, Ireland.
authors: S
authors: S
authors: Fanning
authors: School of Veterinary Medicine, UCD, Dublin, Ireland.
authors: J E
authors: JE
authors: Nally
authors: Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland. Electronic address: kaye.burgess@teagasc.ie.
authors: C M
authors: CM
authors: Burgess
mesh_terms: D044944:Acyl-CoA Dehydrogenases / Q000737:chemistry; D001422:Bacterial Adhesion; D018441:Biofilms; D018938:Caco-2 Cells; D002232:Carbocyanines / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry; D004151:Dipeptides / Q000737:chemistry; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D015180:Electrophoresis, Gel, Two-Dimensional; D019453:Escherichia coli O157 / Q000187:drug effects / Q000201:enzymology*; D020869:Gene Expression Profiling; D006801:Humans; D015151:Immunoblotting; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D009154:Mutation; D010088:Oxidoreductases / Q000378:metabolism; D010641:Phenotype; D020543:Proteome; D040901:Proteomics / Q000379:methods*; D014260:Triclosan / Q000737:chemistry*
chemical_list: D002232:Carbocyanines; D004151:Dipeptides; D020543:Proteome; C419365:phenylalanine arginine beta-naphthylamide; C000657:cyanine dye 1; D014260:Triclosan; D002482:Cellulose; D010088:Oxidoreductases; D044944:Acyl-CoA Dehydrogenases