- Antimicrobial resistance,
- Microbiology
- Biology and
- Microbiology
It is generally assumed that antibiotics can promote horizontal gene transfer. However, because of a variety of confounding factors that complicate the interpretation of previous studies, the mechanisms by which antibiotics modulate horizontal gene transfer remain poorly understood. In particular, it is unclear whether antibiotics directly regulate the efficiency of horizontal gene transfer, serve as a selection force to modulate population dynamics after such gene transfer has occurred, or both. Here, we address this question by quantifying conjugation dynamics in the presence and absence of antibiotic-mediated selection. Surprisingly, we find that sublethal concentrations of antibiotics from the most widely used classes do not significantly increase the conjugation efficiency. Instead, our modelling and experimental results demonstrate that conjugation dynamics are dictated by antibiotic-mediated selection, which can both promote and suppress conjugation dynamics. Our findings suggest that the contribution of antibiotics to the promotion of horizontal gene transfer may have been overestimated. These findings have implications for designing effective antibiotic treatment protocols and for assessing the risks of antibiotic use.
Available at: http://works.bepress.com/robert-smith/11/
A.J.L. conceived the research, designed and performed both modelling and experimental analyses, interpreted the results, and wrote the manuscript. S.H. developed and optimized the microfluidic platform, and assisted in microfluidic experiments and manuscript revisions. R.P.S. conceived the research and assisted in manuscript revisions. J.K.S. assisted with data interpretation, experimental set-up and manuscript revisions. T.A.S. assisted with experiments and manuscript revisions. S.B. and D.K. assisted with manuscript revisions. L.Y. conceived the research, and assisted with research design, data interpretation and manuscript writing.