产超广谱β-内酰胺酶(ESBL)的大肠杆菌(ESBL-EC)被认为是OneHealth界面中最重要的优先病原体之一。然而,很少有研究调查大熊猫ESBL-EC的发生,以及它们的抗生素抗性特征和水平基因转移能力。在这项研究中,我们成功鉴定了12株ESBL-EC(8.33%,12/144)从大熊猫中分离出的144株大肠杆菌中。我们进一步检测了抗生素抗性基因(ARGs),12种ESBL-EC菌株中的毒力相关基因(VAG)和移动遗传元件(MGEs),结果表明,检测到13个ARGs和11个VAGs,其中BLACTX-M(100.00%,12/12,观察到5个变体)和papA(83.33%,10/12)是最普遍的,分别。和ISEcp1(66.67%,8/12)和IS26(66.67%,8/12)是主要的MGE。此外,12种ESBL-EC的水平基因转移能力分析表明,所有blaCTX-M基因都可以通过接合质粒转移,表明高水平的基因转移能力。此外,rmtB和sul2的ARG,papA的VAG,fimC和ompT,发现ISEcp1和IS26的MGE均与blaCTX-M共同转移。系统发育分析将这些ESBL-EC菌株聚类为B2组(75.00%,9/12),D(16.67%,2/12),和B1(8.33%,1/12),在12种ESBL-EC(包括ST48、ST127、ST206、ST354、ST648、ST1706和4种新的ST)中鉴定出10种序列类型(ST)。我们目前的研究表明,圈养大熊猫的ESBL-EC菌株是ARGs的水库,可以通过质粒与blaCTX-M共转移的VAG和MGE。可传播的ESBL-EC菌株具有高度多样性的抗性和毒力元件对人类的潜在威胁,动物和周围环境。
Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) is regarded as one of the most important priority pathogens within the One Health interface. However, few studies have investigated the occurrence of ESBL-EC in giant pandas, along with their antibiotic-resistant characteristics and horizontal gene transfer abilities. In this study, we successfully identified 12 ESBL-EC strains (8.33%, 12/144) out of 144 E. coli strains which isolated from giant pandas. We further detected antibiotic resistance genes (ARGs), virulence-associated genes (VAGs) and mobile genetic elements (MGEs) among the 12 ESBL-EC strains, and the results showed that 13 ARGs and 11 VAGs were detected, of which bla CTX-M (100.00%, 12/12, with 5 variants observed) and papA (83.33%, 10/12) were the most prevalent, respectively. And ISEcp1 (66.67%, 8/12) and IS26 (66.67%, 8/12) were the predominant MGEs. Furthermore, horizontal gene transfer ability analysis of the 12 ESBL-EC showed that all bla CTX-M genes could be transferred by conjugative plasmids, indicating high horizontal gene transfer ability. In addition, ARGs of rmtB and sul2, VAGs of papA, fimC and ompT, MGEs of ISEcp1 and IS26 were all found to be co-transferred with bla CTX-M. Phylogenetic analysis clustered these ESBL-EC strains into group B2 (75.00%, 9/12), D (16.67%, 2/12), and B1 (8.33%, 1/12), and 10 sequence types (STs) were identified among 12 ESBL-EC (including ST48, ST127, ST206, ST354, ST648, ST1706, and four new STs). Our present study showed that ESBL-EC strains from captive giant pandas are reservoirs of ARGs, VAGs and MGEs that can co-transfer with bla CTX-M via plasmids. Transmissible ESBL-EC strains with high diversity of resistance and virulence elements are a potential threat to humans, animals and surrounding environment.