Department of Clinical Analysis, School of Pharmacy, University of São Paulo, São Paulo, Brazil.
Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil.
Vet Res Commun. 2024 Oct;48(5):3355-3363. doi: 10.1007/s11259-024-10456-3. Epub 2024 Jul 8.
The overuse of antimicrobials in livestock has contributed to the emergence and selection of clinically relevant multidrug-resistant bacteria. In Brazil, there is no conclusive information on the occurrence of Escherichia coli producing extended-spectrum β-lactamase (ESβL) in cattle breeding, which is an important sector of agribusiness in this country. Herein, we investigated the presence of ESβL-positive E. coli strains in dairy cattle from a commercial farm with routine practice of therapeutic cephalosporins. Ninety-five rectal swab samples were collected from healthy dairy calves and cows under treatment with ceftiofur. Samples were screened for the presence of ESβL producers, and positive isolates were identified by MALDI-TOF, with subsequent screening for genes encoding ESβL variants by PCR and sequencing. The presence of ESβL (CTX-M-15)-producing E. coli was confirmed in calves, and lactating and dry cows. Most ESβL strains with genetic homologies ≥ 90% were grouped into two major PFGE clusters, confirming the suscessful expansion of clonally related lineages in animals from different lactating cycles, on the same property. Four representatives CTX-M-15-positive E. coli strains had their genomes sequenced, belonging to the clonal complex (CC) 23 and sequence type (ST) 90. A phylogeographical landscape of ST90 was performed revealing a global One Health linkage. Our results highlight the intestinal microbiota of dairy cattle as a hotspot for the spread of critical priority ESβL-producing E. coli and demonstrate that ST90 is an international clone genomically adapted to human and animal hosts, which deserve additional investigation to determine its zoonotic potential and impact in food chain.
兽用抗生素的过度使用导致了临床上相关的多药耐药菌的出现和选择。在巴西，关于牛养殖中产超广谱β-内酰胺酶（ESβL）的大肠杆菌的发生情况尚无明确信息，而牛养殖是该国农业综合企业的一个重要部门。在此，我们调查了一家常规使用头孢菌素治疗药物的商业农场中奶牛中 ESβL 阳性大肠杆菌菌株的存在情况。从健康的奶牛犊牛和接受头孢噻呋治疗的奶牛中采集了 95 份直肠拭子样本。对 ESβL 产生菌进行了筛选，通过 MALDI-TOF 对阳性分离株进行了鉴定，随后通过 PCR 和测序对编码 ESβL 变体的基因进行了筛选。在犊牛、泌乳牛和干奶牛中均确认存在 ESβL（CTX-M-15）产生的大肠杆菌。具有遗传同源性≥90%的大多数 ESβL 菌株被分为两个主要的 PFGE 聚类，证实了具有克隆相关谱系的动物在同一属性的不同泌乳周期中成功扩张。对 4 株 CTX-M-15 阳性大肠杆菌代表株的基因组进行了测序，它们属于克隆复合体（CC）23 和序列型（ST）90。对 ST90 的系统发育景观进行了分析，揭示了全球一个健康的联系。我们的结果强调了奶牛的肠道微生物群是传播关键优先级 ESβL 产生的大肠杆菌的热点，并表明 ST90 是一种在人类和动物宿主中具有遗传适应性的国际克隆，值得进一步研究，以确定其人畜共患病潜力及其对食物链的影响。
