Guzman-Cole Candace, Santiago Fabian, Garsevanyan Sona, Sindi Suzanne, Barlow Miriam
Department of Molecular and Cell Biology, School of Natural Sciences, University of California Merced, Merced, CA 95343, USA.
Department of Applied Mathematics, School of Natural Sciences, University of California, Merced, CA 95343, USA.
Antibiotics (Basel). 2021 Apr 27;10(5):498. doi: 10.3390/antibiotics10050498.
The evolution and dissemination of antibiotic resistance genes throughout the world are clearly affected by the selection and migration of resistant bacteria. However, the relative contributions of selection and migration at a local scale have not been fully explored. We sought to identify which of these factors has the strongest effect through comparisons of antibiotic resistance gene abundance between a distinct location and its surroundings over an extended period of six years. In this work, we used two repositories of extended spectrum β-lactamase (ESBL)-producing isolates collected since 2013 from patients at Dignity Health Mercy Medical Center (DHMMC) in Merced, California, USA, and a nationwide database compiled from clinical isolate genomes reported by the National Center for Biotechnology Information (NCBI) since 2013. We analyzed the stability of average resistance gene frequencies over the years since collection of these clinical isolates began for each repository. We then compared the frequencies of resistance genes in the DHMMC collection with the averages of the nationwide frequencies. We found DHMMC gene frequencies are stable over time and differ significantly from nationwide frequencies throughout the period of time we examined. Our results suggest that local selective pressures are a more important influence on the population structure of resistance genes in bacterial populations than migration. This, in turn, indicates the potential for antibiotic resistance to be controlled at a regional level, making it easier to limit the spread through local stewardship.
抗生素耐药基因在全球的演变和传播显然受到耐药细菌的选择和迁移的影响。然而，局部尺度上选择和迁移的相对作用尚未得到充分探究。我们试图通过比较一个特定地点及其周边环境在长达六年的时间里抗生素耐药基因丰度，来确定这些因素中哪一个影响最强。在这项研究中，我们使用了两个储存库，一个是自2013年以来从美国加利福尼亚州默塞德尊严健康慈悲医疗中心（DHMMC）的患者中收集的产超广谱β-内酰胺酶（ESBL）分离株，另一个是自2013年以来由美国国家生物技术信息中心（NCBI）报道的临床分离株基因组汇编而成的全国性数据库。我们分析了自每个储存库开始收集这些临床分离株以来多年间平均耐药基因频率的稳定性。然后我们将DHMMC收集的耐药基因频率与全国频率的平均值进行了比较。我们发现DHMMC的基因频率随时间稳定，并且在我们研究的整个时间段内与全国频率有显著差异。我们的结果表明，局部选择压力对细菌群体中耐药基因的种群结构的影响比迁移更为重要。这反过来表明在区域层面控制抗生素耐药性的潜力，使得通过局部管理更容易限制其传播。
