Abstract：
Escherichia coli is one of the key bacteria responsible for a variety of diseases in humans and livestock-associated infections around the globe. It is the leading cause of mortality in neonatal and weaned piglets in pig husbandry, causing diarrhea and significant harm to the industry. Furthermore, the frequent and intensive use of antimicrobials for the prevention of diseases, particularly gastrointestinal diseases, may promote the selection of multidrug-resistant (MDR) strains. These resistant genotypes can be transmitted through the excrement of animals, including swine. It is common practice to use porcine manure processed by biodigesters as fertilizer. This study aimed to examine the antimicrobial susceptibility, the presence of virulence genes frequently associated with pathotypes of intestinal pathogenic E. coli (InPEC), and antimicrobial resistance genes (ARGs) of 28 E. coli isolates collected from swine manure fertilizers. In addition, the enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) technique was used to investigate the genetic relationship among the strains. Using disk diffusion, the antimicrobial susceptibility profiles of the strains were determined. Using polymerase chain reaction (PCR), 14 distinct virulence genes associated with the most prevalent diarrhea and intestinal pathogenic E. coli (DEC/InPEC) and five ARGs were analyzed. All isolates tested positive for multidrug resistance. There was no detection of any of the 14 virulence genes associated with InPECs, indicating the presence of an avirulent commensal microbiota. Molecular classification by ERIC-PCR revealed that the majority of isolates (27 isolates) coalesced into a larger cluster with a genetic similarity of 47.7%; only one strain did not cluster in this cluster, indicating a high level of genetic diversity among the analyzed isolates. Thus, it is of the utmost importance to conduct epidemiological surveillance of animal breeding facilities in order to determine their microbiota and formulate plans to reduce the use of antimicrobials and improve animal welfare.
摘要：
大肠杆菌是导致全球人类和牲畜相关感染的各种疾病的关键细菌之一。它是养猪业中新生和断奶仔猪死亡的主要原因，引起腹泻并对行业造成重大危害。此外，频繁和密集地使用抗菌药物来预防疾病，尤其是胃肠道疾病，可能促进多药耐药(MDR)菌株的选择。这些抗性基因型可以通过动物的排泄物传播，包括猪。通常的做法是使用由生物消化器加工的猪粪作为肥料。这项研究旨在检查抗菌药物的敏感性，毒力基因的存在经常与肠道致病性大肠杆菌（InPEC）的致病型相关，和从猪粪肥料中收集的28个大肠杆菌分离株的抗菌素抗性基因(ARGs)。此外,使用肠杆菌重复基因间共有PCR（ERIC-PCR）技术来研究菌株之间的遗传关系。使用磁盘扩散，确定了菌株的抗菌药物敏感性。使用聚合酶链反应（PCR），分析了与最普遍的腹泻和肠道致病性大肠杆菌（DEC/InPEC）相关的14种不同的毒力基因和5种ARG。所有分离株的多药耐药性检测呈阳性。没有检测到与InPEC相关的14个毒力基因中的任何一个，表明存在无毒共生微生物群。通过ERIC-PCR进行分子分类显示，大多数分离株（27个分离株）合并为一个较大的簇，遗传相似性为47.7％；只有一个菌株没有在该簇中聚集，表明分析的分离株之间的遗传多样性水平很高。因此，最重要的是对动物育种设施进行流行病学监测，以确定其微生物群，并制定计划以减少抗微生物剂的使用和改善动物福利。
