Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, PR China.
Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, PR China; Institute of Comparative Medicine, Yangzhou University, Yangzhou, PR China.
Ecotoxicol Environ Saf. 2022 Oct 1;244:114032. doi: 10.1016/j.ecoenv.2022.114032. Epub 2022 Sep 7.
The emergence of multidrug-resistant (MDR) bacteria harboring tet(X4), bla or mcr-1 posed a serious threat to public health. Wild birds, especially migratory birds, were considered as one of important transmission vectors for antibiotic resistance genes (ARGs) globally, however, few studies were performed on the genomic epidemiology of critical resistance genes among them. Isolates harboring tet(X4), mcr-1 or bla from migratory birds were identified and characterized by PCR, antimicrobial susceptibility testing, conjugation assays, whole genome sequencing and bioinformatics analysis. A total of 14 tet(X4)-bearing E. coli, 4 bla-bearing E. coli and 23 mcr-1-bearing E. coli isolates were recovered from 1060 fecal samples of migratory birds. All isolates were MDR bacteria and most plasmids carrying tet(X4), bla or mcr-1 were conjugative. We first identified an E. coli of migratory bird origin carrying bla, which was located on a conjugative IncHI2 plasmid and embedded on a novel MDR region flanked by IS26 that could generate the circular intermediate. The emergency of E. coli isolates co-harboring mcr-1 and bla in migratory birds indicated the coexistence of ARGs in migratory birds was a novel threat. This study revealed the prevalence and molecular characteristics of three important ARGs in migratory birds, provided evidence that migratory birds were potential vectors of novel resistance genes and highlighted the monitoring of ARGs in migratory birds should be strengthened to prevent the spread of ARGs in a One Health strategy.
携带有 tet(X4)、bla 或 mcr-1 的多药耐药（MDR）细菌的出现对公共卫生构成了严重威胁。野生鸟类，尤其是候鸟，被认为是全球抗生素耐药基因（ARGs）的重要传播媒介之一，但针对其中关键耐药基因的基因组流行病学研究较少。通过 PCR、药敏试验、接合试验、全基因组测序和生物信息学分析，从候鸟中鉴定和表征携带 tet(X4)、mcr-1 或 bla 的分离株。从 1060 份候鸟粪便样本中回收了 14 株携带 tet(X4)的大肠杆菌、4 株携带 bla 的大肠杆菌和 23 株携带 mcr-1 的大肠杆菌分离株。所有分离株均为 MDR 细菌，大多数携带 tet(X4)、bla 或 mcr-1 的质粒均具有接合性。我们首次鉴定出一株来自候鸟的携带 bla 的大肠杆菌，该bla 位于可产生环形中间体的可移动 IncHI2 质粒上，且嵌入在由 IS26 侧翼的新型 MDR 区域中。在候鸟中共同携带 mcr-1 和 bla 的大肠杆菌分离株的出现表明，ARGs 在候鸟中的共存是一种新的威胁。本研究揭示了候鸟中三种重要 ARGs 的流行情况和分子特征，为候鸟是新型耐药基因的潜在传播媒介提供了证据，并强调应加强对候鸟中 ARGs 的监测，以防止 One Health 策略中 ARGs 的传播。
