Department of Animal Science, The University of Tennessee Institute of Agriculture, Knoxville, Tennessee, USA.
Food Animal Environmental Systems Research Unit, Agricultural Research Service, United States Department of Agriculture, Bowling Green, Kentucky, USA.
Foodborne Pathog Dis. 2022 Jun;19(6):408-416. doi: 10.1089/fpd.2021.0101. Epub 2022 Apr 22.
Antimicrobials have been widely used in dairy farms to prevent and control dairy cattle diseases since 1960s. This led to the emergence of antimicrobial resistant bacteria (ARB) that, along with their antimicrobial resistance genes (ARGs), can spread from dairy farms to humans. Therefore, regular antimicrobial resistance (AMR) monitoring is important to implement proper mitigation measures. The objective of this study was to determine the prevalence of AMR and extended-spectrum beta-lactamases (ESBLs)-producing in dairy cattle. A cross-sectional study was conducted in four dairy cattle farms (A-D) in East Tennessee. A total of 80 samples consisting of 20 samples each of bulk tank milk, feces, dairy cattle manure-amended soil, and prairie soil adjacent to the farms were collected and cultured for the isolation of . Tetracycline (TET)-, third-generation cephalosporin (TGC)- and nalidixic acid (NAL)-resistant ( = 88) were isolated and identified on agar media supplemented with TET, cefotaxime, and NAL, respectively. TGC were tested for ESBLs and other coselected ARGs. TET (74%, = 88) was the most common, followed by TGC (20%) and NAL (8%). Farms had significant ( < 0.001) differences: the highest prevalence of TGC (55%) and TET (100%) were observed in farm D, while all NAL isolates were from farm C. Over 83% of TGC isolates ( = 18) harbored ESBL gene . Majority (78%) of the isolates were multidrug-resistant (MDR), being positive for beta-lactams (), TETs (), (), ()), sulfonamides (2), aminoglycosides (), and phenicols (). This study indicated the widespread occurrence of MDR ESBLs- in dairy cattle farms. AMR surveillance of more dairy farms and identification of farm-level risk factors are important to mitigate the occurrence and spread of ARB of significant public health importance, such as ESBLs-.
自 20 世纪 60 年代以来，抗生素在奶牛场被广泛用于预防和控制奶牛疾病。这导致了抗微生物药物耐药细菌（ARB）的出现，这些细菌及其抗微生物药物耐药基因（ARGs）可以从奶牛场传播到人类。因此，定期进行抗微生物药物耐药性（AMR）监测对于实施适当的缓解措施非常重要。本研究的目的是确定奶牛中 AMR 和产超广谱β-内酰胺酶（ESBLs）的流行情况。在田纳西州东部的四个奶牛场（A-D）进行了横断面研究。共采集了 80 份样本，每份样本包括 20 份来自大容量奶罐奶、粪便、奶牛粪便改良土壤和农场附近草原土壤的样本，并进行培养以分离 。在添加了四环素（TET）、头孢噻肟和萘啶酸（NAL）的琼脂培养基上分别分离和鉴定了对 TET（TET-）、第三代头孢菌素（TGC-）和萘啶酸（NAL-）耐药的 。TGC 被测试是否产 ESBLs 和其他共选择的 ARGs。TET（74%， = 88）是最常见的，其次是 TGC（20%）和 NAL（8%）。农场之间存在显著差异（ < 0.001）：在农场 D 中观察到 TGC（55%）和 TET（100%）的最高流行率，而所有 NAL 分离株均来自农场 C。超过 83%的 TGC 分离株（ = 18）携带 ESBL 基因 。大多数（78%） 分离株为多重耐药（MDR），对β-内酰胺类（）、TETs（）、（）、（））、磺胺类（2）、氨基糖苷类（）和酚类（）呈阳性。本研究表明，MDR ESBLs-在奶牛场中广泛存在。对更多奶牛场进行 AMR 监测并确定农场层面的风险因素对于减轻具有重要公共卫生意义的 ARB（如 ESBLs-）的发生和传播非常重要。
