Exposure of Escherichia coli and Salmonella enterica serovar Typhimurium to triclosan induces a species-specific response, including drug detoxification

Andrew M. Bailey, Chrystala Constantinidou, Al Ivens, Mark I. Garvey, Mark A. Webber, Nick Coldham, Jon L. Hobman, John Wain, Martin J. Woodward, Laura J.V. Piddock*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    55 Citations (Scopus)


    Objectives: The use of triclosan within various environments has been linked to the development of multiple drug resistance (MDR) through the increased expression of efflux pumps such as AcrAB-TolC. In this work, we investigate the effect of triclosan exposure in order to ascertain the response of two species to the presence of this widely used biocide. Methods: The transcriptomes of Salmonella enterica serovar Typhimurium SL1344 and Escherichia coli K-12 MG1655 after exposure to the MIC of triclosan (0.12 mg/L) were determined in microarray experiments. Phenotypic validation of the transcriptomic data included RT-PCR, ability to form a biofilm and motility assays. Results: Despite important differences in the triclosan-dependent transcriptomes of the two species, increased expression of efflux pump component genes was seen in both. Increased expression of soxS was observed in Salmonella Typhimurium, however, within E. coli, decreased expression was seen. Expression of fabBAGI in Salmonella Typhimurium was decreased, whereas in E. coli expression of fabABFH was increased. Increased expression of ompR and genes within this regulon (e.g. ompC, csgD and ssrA) was seen in the transcriptome of Salmonella Typhimurium. An unexpected response of E. coli was the differential expression of genes within operons involved in iron homeostasis; these included fhu, fep and ent. Conclusions: These data indicate that whilst a core response to triclosan exposure exists, the differential transcriptome of each species was different. This suggests that E. coli K-12 should not be considered the paradigm for the Enterobacteriaceae when exploring the effects of antimicrobial agents.

    Original languageEnglish
    Article numberdkp320
    Pages (from-to)973985
    Number of pages973985
    JournalJournal of Antimicrobial Chemotherapy
    Issue number5
    Publication statusPublished - 16 Sept 2009

    Bibliographical note

    Funding Information:
    A. M. B. and M. I. G. were supported by the Bristol-Myers Squibb Foundation Non-Restrictive Grant in Infectious Diseases to L. J. V. P., M. A. W. by BBSRC Grant BB/DD20476/1, A. I. and J. W. by The Wellcome Trust, M. J. W. and N. C. by Defra and C. C. and J. L. H. by BBSRC Grant EGA16107.

    Copyright 2010 Elsevier B.V., All rights reserved.


    • Biocide
    • Efflux
    • Transcriptome


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