摘要
      自20世纪60年代以来，抗菌药物在奶牛场被广泛用于预防和控制奶牛疾病。这导致了抗微生物细菌（ARB）的出现，这些细菌及其抗微生物基因（ARG）可以从奶牛场传播给人类。因此，定期监测抗微生物耐药性（AMR）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）的大肠杆菌的患病率。一项横断面研究在田纳西州东部的四个奶牛场（A-D）进行。共收集了80个样本，包括散装罐奶、粪便、奶牛粪便改良土壤和农场附近的草原土壤各20个样本，并进行培养以分离大肠杆菌。四环素（TETr）、第三代头孢菌素（TGCr）和萘啶酸（NALr）耐药大肠杆菌（n = 88）分别在补充有TET、头孢噻肟和NAL的琼脂培养基上分离和鉴定。TGCrE公司。对大肠杆菌进行ESBLs和其他共同选择的ARGs测试。TETr（74%，n = 88）最常见，其次是TGCr（20%）和NALr（8%）。农场有显著的（p < 0.001）差异：在D农场观察到TGCr（55%）和TETr（100%）的最高流行率，而所有NALr分离株都来自C农场。超过83%的TGCr分离株（n = 18） 携带ESBL基因blaCTX-M。大多数（78%）大肠杆菌分离株是耐多药（MDR）菌株，对β-内酰胺类（blaCTX-M）、TETs-tet（A）、tet（B）、tet（M））、磺酰胺类（sul2）、氨基糖苷类（strA）和酚类（floR）呈阳性。本研究表明耐多药ESBLs-E广泛存在。奶牛场中的大肠杆菌。对更多奶牛场的AMR监测和农场级风险因素的识别对于缓解具有重大公共卫生重要性的ARB（如ESBLs-E）的发生和传播至关重要。大肠杆菌。
Abstract
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 Escherichia coli 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 E. coli. Tetracycline (TETr)-, third-generation cephalosporin (TGCr)- and nalidixic acid (NALr)-resistant E. coli (n = 88) were isolated and identified on agar media supplemented with TET, cefotaxime, and NAL, respectively. TGCrE. coli were tested for ESBLs and other coselected ARGs. TETr (74%, n = 88) was the most common, followed by TGCr (20%) and NALr (8%). Farms had significant (p < 0.001) differences: the highest prevalence of TGCr (55%) and TETr (100%) were observed in farm D, while all NALr isolates were from farm C. Over 83% of TGCr isolates (n = 18) harbored ESBL gene blaCTX-M. Majority (78%) of the E. coli isolates were multidrug-resistant (MDR), being positive for beta-lactams (blaCTX-M), TETs tet(A), tet(B), tet(M)), sulfonamides (sul2), aminoglycosides (strA), and phenicols (floR). This study indicated the widespread occurrence of MDR ESBLs-E. coli 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-E. coli.

https://www.liebertpub.com/doi/full/10.1089/fpd.2021.0101