CIRI - Centre International de Recherche en Infectiologie, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, F-69007, Lyon, France.
Centre National de Référence des Staphylocoques, Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France.
ISME J. 2018 Aug;12(8):1879-1894. doi: 10.1038/s41396-018-0110-4. Epub 2018 Mar 29.
Community-acquired (CA)- as opposed to hospital acquired- methicillin-resistant Staphylococcus aureus (MRSA) lineages arose worldwide during the 1990s. To determine which factors, including selective antibiotic pressure, govern the expansion of two major lineages of CA-MRSA, namely "USA300" in Northern America and "European ST80" in North Africa, Europe and Middle-East, we explored virulence factor expression, and fitness levels with or without antibiotics. The sampled strains were collected in a temporal window representing various steps of the epidemics, reflecting predicted changes in effective population size as inferred from whole-genome analysis. In addition to slight variations in virulence factor expression and biofilm production that might influence the ecological niches of theses lineages, competitive fitness experiments revealed that the biological cost of resistance to methicillin, fusidic acid and fluoroquinolones is totally reversed in the presence of trace amount of antibiotics. Our results suggest that low-level antibiotics exposure in human and animal environments contributed to the expansion of both European ST80 and USA300 lineages in community settings. This surge was likely driven by antibiotic (ab)use promoting the accumulation of antibiotics as environmental pollutants. The current results provide a novel link between effective population size increase of a pathogen and a selective advantage conferred by antibiotic resistance.
社区获得性(CA)- 与医院获得性-耐甲氧西林金黄色葡萄球菌(MRSA)谱系在 20 世纪 90 年代在全球范围内出现。为了确定哪些因素,包括选择性抗生素压力,控制两个主要的 CA-MRSA 谱系,即北美“USA300”和北非、欧洲和中东的“欧洲 ST80”的扩张,我们探索了毒力因子表达,并在有或没有抗生素的情况下测量了适应度水平。采样菌株是在代表流行过程各个步骤的时间窗口中收集的,反映了从全基因组分析推断的有效种群大小的预测变化。除了可能影响这些谱系生态位的毒力因子表达和生物膜产生的微小变化外,竞争适应度实验表明,在存在痕量抗生素的情况下,对甲氧西林、夫西地酸和氟喹诺酮的耐药性的生物学代价完全逆转。我们的研究结果表明,人类和动物环境中的低水平抗生素暴露促进了欧洲 ST80 和 USA300 谱系在社区环境中的扩张。这种激增可能是由于抗生素(滥用)促进了抗生素作为环境污染物的积累。目前的研究结果为病原体有效种群大小增加与抗生素耐药性赋予的选择性优势之间提供了新的联系。