Seier-Petersen, Maria Amalie1; Jasni, A.5; Aarestrup, Frank Møller2; Vigre, Håkan2; Mullany, P.5; Roberts, A. P.5; Agersø, Yvonne2
1 Comparative Microbial Genomics, Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark2 National Food Institute, Technical University of Denmark3 Division of Epidemiology and Microbial Genomics, National Food Institute, Technical University of Denmark4 National Veterinary Institute, Technical University of Denmark5 University College London
Objectives Large amounts of biocides are used to reduce and control bacterial growth in the healthcare sector, food production and agriculture. This work explores the effect of subinhibitory concentrations of four commonly used biocides (ethanol, hydrogen peroxide, chlorhexidine digluconate and sodium hypochlorite) on the conjugative transposition of the mobile genetic element Tn916.Methods Conjugation assays were carried out between Bacillus subtilis strains. The donor containing Tn916 was pre-exposed to subinhibitory concentrations of each biocide for a defined length of time, which was determined by an analysis of the transcriptional response of the promoter upstream of tet(M) using β-glucuronidase reporter assays.Results Ethanol significantly (P = 0.01) increased the transfer of Tn916 by 5-fold, whereas hydrogen peroxide, chlorhexidine digluconate and sodium hypochlorite did not significantly affect the transfer frequency.Conclusions These results suggest that exposure to subinhibitory concentrations of ethanol may induce the transfer of Tn916-like elements and any resistance genes they contain.
Journal of Antimicrobial Chemotherapy, 2014, Vol 69, Issue 2, p. 343-348