Dipartimento di Scienze Mediche Veterinarie Università di Bologna, Italy; Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, KT15 3NB, UK.
Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, KT15 3NB, UK.
Vet Microbiol. 2021 Jul;258:109125. doi: 10.1016/j.vetmic.2021.109125. Epub 2021 May 15.
An important element in the control of antimicrobial resistance (AMR) is reduction in antimicrobial usage. In the veterinary sector individual antimicrobial treatment of livestock, rather than the use of group treatment, can help achieve this goal. The aim of this study was to investigate how cessation of group antimicrobial treatment impacted the prevalence of AMR in commensal Escherichia coli in pigs at one farm over an 11-month period. Minimum inhibitory concentrations of eight antimicrobials were determined for 259 E. coli isolates collected during the study. A significant reduction in the prevalence of multidrug resistance and a significant increase in the proportion of full susceptibility to the panel of nine antimicrobials tested was seen after 11 months. Whole genome sequencing of 48 multidrug resistant isolates revealed E. coli clones that persisted across multiple visits and provided evidence for the presence of plasmids harbouring AMR genes shared across multiple E. coli lineages. E. coli were also isolated from on-farm environmental samples. Whole genome sequencing of one multidrug resistant isolate obtained from cleaning tools showed it was clonal to pig-derived E. coli that persisted on the farm for 11 months. In this study we provide evidence that withdrawal of group antimicrobial use leads to significant reductions in key indicators for AMR prevalence and the importance of the farm environment as a reservoir of resistant bacteria. These findings support policy makers and producers in the implementation of measures to control AMR and reduce antimicrobial use.
控制抗菌药物耐药性（AMR）的一个重要因素是减少抗菌药物的使用。在兽医领域，对牲畜进行个体抗菌药物治疗而不是群体治疗，可以帮助实现这一目标。本研究旨在调查在一个农场的 11 个月期间停止群体抗菌药物处理如何影响猪肠道共生大肠杆菌中 AMR 的流行情况。在研究过程中收集了 259 株大肠杆菌分离株，测定了 8 种抗菌药物的最小抑菌浓度。经过 11 个月，观察到多药耐药性的流行率显著降低，对测试的 9 种抗菌药物的完全敏感性比例显著增加。对 48 株多药耐药分离株进行全基因组测序，发现了在多次访问中持续存在的大肠杆菌克隆，并提供了证据证明存在携带 AMR 基因的质粒，这些基因在多个大肠杆菌谱系中共享。还从农场环境样本中分离出了大肠杆菌。从清洁工具中获得的一株多药耐药分离株的全基因组测序表明，它与在农场中持续存在 11 个月的猪源性大肠杆菌具有克隆关系。在本研究中，我们提供了证据表明，停止群体使用抗菌药物会导致 AMR 流行的关键指标显著降低，以及农场环境作为耐药菌库的重要性。这些发现为决策者和生产者实施控制 AMR 和减少抗菌药物使用的措施提供了支持。
