Novel Insights into Selection for Antibiotic Resistance in Complex Microbial Communities

mBio

卷:9

Lihong Zhang¹  Tong Zhang¹  William H. Gaze²  Jason Snape³  Angus Buckling³  Xiaole Yin⁴  Aimee K. Murray⁴ 

[1] Sustainability Institute, Penryn, Cornwall, United Kingdom;

[2] College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, United Kingdom;

[3] Department for Civil Engineering, University of Hong Kong, Hong Kong, China;

[4] European Centre for Environment and Human Health, University of Exeter Medical School, Environment &

关键词: antibiotic resistance;    evolution;    metagenomics;    microbial ecology;   

DOI  :  10.1128/mBio.00969-18

来源: DOAJ

【 摘 要 】

ABSTRACT Recent research has demonstrated that selection for antibiotic resistance occurs at very low antibiotic concentrations in single-species experiments, but the relevance of these findings when species are embedded in complex microbial communities is unclear. We show that the strength of selection for naturally occurring resistance alleles in a complex community remains constant from low subinhibitory to above clinically relevant concentrations. Selection increases with antibiotic concentration before reaching a plateau where selection remains constant over a 2-order-magnitude concentration range. This is likely to be due to cross protection of the susceptible bacteria in the community following rapid extracellular antibiotic degradation by the resistant population, shown experimentally through a combination of chemical quantification and bacterial growth experiments. Metagenome and 16S rRNA analyses of sewage-derived bacterial communities evolved under cefotaxime exposure show preferential enrichment for blaCTX-M genes over all other beta-lactamase genes, as well as positive selection and co-selection for antibiotic resistant, opportunistic pathogens. These findings have far-reaching implications for our understanding of the evolution of antibiotic resistance, by challenging the long-standing assumption that selection occurs in a dose-dependent manner. IMPORTANCE Antibiotic resistance is one of the greatest global issues facing society. Still, comparatively little is known about selection for resistance at very low antibiotic concentrations. We show that the strength of selection for clinically important resistance genes within a complex bacterial community can remain constant across a large antibiotic concentration range (wide selective space). Therefore, largely understudied ecological compartments could be just as important as clinical environments for selection of antibiotic resistance.

【 授权许可】

Unknown