Multiple adaptive routes of Salmonella enterica Typhimurium to biocide and antibiotic exposure.pdf (2.27 MB)
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Multiple adaptive routes of Salmonella enterica Typhimurium to biocide and antibiotic exposure

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journal contribution
posted on 10.10.2016, 15:28 by Tânia Curiao, Emmanuela Marchi, Denis Grandgirard, Ricardo León-Sampedro, Carlo Viti, Stephen L. Leib, Fernando Baquero, Marco R. Oggioni, José Luis Martinez, Teresa M. Coque
BACKGROUND: 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. RESULTS: 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. CONCLUSIONS: 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.

History

Citation

BMC Genomics, 2016, 17:491

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/MBSP Non-Medical Departments/Department of Genetics

Version

VoR (Version of Record)

Published in

BMC Genomics

Publisher

BioMed Central

issn

1471-2164

Acceptance date

26/05/2016

Copyright date

2016

Available date

10/10/2016

Publisher version

http://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-016-2778-z

Language

en