Open AccessEffect of triclosan on Salmonella typhimurium at different growth stages and in biofilms
Author(s) -
Tabak Mina,
Scher Keren,
Hartog Efrat,
Romling Ute,
Matthews Karl R.,
Chikindas Michael L.,
Yaron Sima
Publication year - 2007
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2006.00547.x
Subject(s) - biofilm , triclosan , microbiology and biotechnology , salmonella enterica , efflux , bacteria , chemistry , mutant , multidrug tolerance , biology , salmonella , gene , biochemistry , genetics , medicine , pathology
Triclosan is a potent biocide that is included in a diverse range of products. This research was aimed to investigate the susceptibility of planktonic and biofilm‐associated Salmonella enterica serovar Typhimurium to triclosan, and to identify potential mechanisms of adaptation. The effect of triclosan was studied on planktonic Salmonella (log and stationary phases), on biofilm‐associated cells, on bacteria derived from disrupted biofilms and on a biofilm‐deficient mutant. An eight‐log reduction of exponentially growing cells was observed with 1000 μg mL −1 triclosan within 10 min, a 3.6‐log reduction in stationary cells and a 6.3‐log reduction in stationary cells of a biofilm‐deficient mutant ( P <0.05). Biofilm‐associated cells were tolerant (1‐log reduction). However, biofilm‐derived cells showed sensitivity to triclosan similar to stationary‐phase cells. Triclosan induced the transcription of fabI and micF . Within biofilms, triclosan also up‐regulated the transcription of acrAB , encoding for an efflux pump, marA , and the cellulose‐synthesis‐coding genes bcsA and bcsE . Thus, Salmonella within biofilms could experience reduced influx, increased efflux and enhanced exopolysaccharides production. Our results demonstrated that the tolerance of Salmonella towards triclosan in the biofilm was attributed to low diffusion through the extracellular matrix, while changes of gene expression might provide further resistance to triclosan and to other antimicrobials.