We evaluated the prevalence and epidemiology of extended‐spectrum beta‐lactamase (ESBL)‐producing Escherichia coli isolates in pigs during production cycle on a Czech farm with the history of previous use of ceftiofur. ESBL‐producing E. coli isolates were obtained from rectal swabs from pigs of different age groups (suckling piglets, weaned piglets, growers and sows). Collected samples were directly cultivated on MacConkey agar with cefotaxime (2 mg l−1), whereas intestinal swabs of slaughtered pigs and surface swabs from pig carcasses were also pre‐enriched in buffered peptone water without antimicrobials before the cultivation. Clonal relationship of selected isolates was determined by XbaI pulse‐field gel electrophoresis and multi‐locus sequence typing. The transferability of plasmids carrying blaCTX‐M genes was tested by conjugation experiments. From all examined samples, 141 (43·7%, n = 323) were positive for ESBL‐producing E. coli. All ESBL‐producing isolates showed resistance to multiple antimicrobials and were positive for blaCTX‐M genes. The blaCTX‐M‐1 was carried by conjugative IncN/ST1 plasmids (c. 40–45 kb) while the blaCTX‐M‐15 was located on conjugative F plasmids with F:18:A5:B1 formula (c. 165 kb). This study demonstrated the persistence of CTX‐M‐positive E. coli isolates 2 months after banner of ceftiofur usage and indicated possible risk of transmission of these isolates to humans via the food chain.

中文翻译：

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捷克农场猪在生产周期中产 CTX-M 的大肠杆菌

我们评估了捷克猪场生产周期中产超广谱 β-内酰胺酶 (ESBL) 大肠杆菌分离株的流行率和流行病学情况，该猪场以前使用过头孢噻呋。从不同年龄组（哺乳仔猪、断奶仔猪、生长猪和母猪）的直肠拭子中获得产 ESBL 的大肠杆菌分离株。收集的样品直接在含有头孢噻肟（2 mg l-1）的 MacConkey 琼脂上培养，而屠宰猪的肠拭子和猪尸体的表面拭子也在培养前用不含抗菌剂的缓冲蛋白胨水中预富集。通过 XbaI 脉冲场凝胶电泳和多位点序列分型确定所选分离株的克隆关系。通过缀合实验测试携带 blaCTX-M 基因的质粒的可转移性。在所有检查的样本中，141 个（43·7%，n = 323）对产 ESBL 的大肠杆菌呈阳性。所有产 ESBL 的分离株均显示对多种抗菌剂的耐药性，并且对 blaCTX-M 基因呈阳性。blaCTX-M-1 由结合的 IncN/ST1 质粒（c. 40–45 kb）携带，而 blaCTX-M-15 位于具有 F:18:A5:B1 式（c. 165 kb）的结合 F 质粒上. 这项研究证明了 CTX-M 阳性大​​肠杆菌分离株在使用头孢噻呋后 2 个月的持续存在，并表明这些分离株可能存在通过食物链传播给人类的风险。所有产 ESBL 的分离株均显示对多种抗菌剂的耐药性，并且对 blaCTX-M 基因呈阳性。blaCTX-M-1 由结合的 IncN/ST1 质粒（c. 40–45 kb）携带，而 blaCTX-M-15 位于具有 F:18:A5:B1 式（c. 165 kb）的结合 F 质粒上. 这项研究证明了 CTX-M 阳性大​​肠杆菌分离株在使用头孢噻呋后 2 个月的持续存在，并表明这些分离株可能存在通过食物链传播给人类的风险。所有产 ESBL 的分离株均显示对多种抗菌剂的耐药性，并且对 blaCTX-M 基因呈阳性。blaCTX-M-1 由结合的 IncN/ST1 质粒（c. 40–45 kb）携带，而 blaCTX-M-15 位于具有 F:18:A5:B1 式（c. 165 kb）的结合 F 质粒上. 这项研究证明了 CTX-M 阳性大​​肠杆菌分离株在使用头孢噻呋后 2 个月的持续存在，并表明这些分离株可能存在通过食物链传播给人类的风险。