Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, Yangzhou University, Yangzhou 225009, China.
Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China.
Poult Sci. 2024 Jun;103(6):103608. doi: 10.1016/j.psj.2024.103608. Epub 2024 Mar 6.
Salmonella, which is widely distributed in nature, is an important zoonotic pathogen affecting humans, livestock, and other animals. Salmonella infection not only hinders the development of livestock and poultry-related industries but also poses a great threat to human health. In this study, we collected 1,537 samples including weak chicks, dead embryos, fecal samples and environmental samples from 2020 to 2023 (for a period of 1 to 2 months per year) to keep a long-term monitor the prevalence of Salmonella in an intensive laying hen farm, 105 Salmonella strains were isolated with an isolation rate of 6.83% (105/1,537). It revealed a significant decrease in prevalence rates of Salmonella over time (P < 0.001). Before 2020, the predominant serotype was S. Enteritidis. S. Kentucky was first detected in November 2020 and its proportion was gradually found to exceed that of S. Enteritidis since then. S. Kentucky isolates were distributed in various links of the four regions in the poultry farm. A total of 55 S. Kentucky strains, were assigned to ST198 based on whole genome sequencing. Among them, 54 strains were resistant to 12 to 16 antibiotics, indicating that they were extensively drug-resistant (XDR). Seventeen antimicrobial resistance genes were detected in 55 S. Kentucky isolates. For most of these isolates, antibiotic resistance phenotypes were concordant with their genotypes. All S. Kentucky strains isolated from this farm in 2020 to 2023 showed a high similarity based on their core-genome SNP-based phylogeny. The traceability analysis revealed that S. Kentucky was introduced to the farm through newly purchased flocks. The long-term existence of XDR S. Kentucky ST198 poses a substantial risk because of the multiage management and circulation of workers in this poultry farm. Thus, this study is the first to report extensively drug-resistant S. Kentucky ST198 detected in this intensive poultry farm in China.
沙门氏菌广泛分布于自然界，是一种重要的人畜共患病病原体，可感染人类、家畜和其他动物。沙门氏菌感染不仅阻碍了畜牧业和家禽业的发展，也对人类健康构成了巨大威胁。在本研究中，我们于 2020 年至 2023 年（每年 1 至 2 个月）期间，从弱雏、死胚、粪便和环境样本中收集了 1537 份样本，对一个密集型蛋鸡养殖场中的沙门氏菌流行情况进行了长期监测。共分离出 105 株沙门氏菌，分离率为 6.83%（105/1537）。结果表明，沙门氏菌的流行率随时间显著下降（P<0.001）。在 2020 年之前，主要血清型为肠炎沙门氏菌。2020 年 11 月首次检测到肯塔基沙门氏菌，此后其比例逐渐超过肠炎沙门氏菌。肯塔基沙门氏菌分离株分布在禽场四个区域的各个环节。共对 55 株肯塔基沙门氏菌进行了全基因组测序，基于全基因组测序将其分为 ST198 型。其中，54 株对 12 至 16 种抗生素耐药，提示其为广泛耐药（XDR）。在 55 株肯塔基沙门氏菌中检测到 17 种抗菌药物耐药基因。对于大多数分离株，抗生素耐药表型与其基因型一致。2020 年至 2023 年从该场分离的所有肯塔基沙门氏菌基于核心基因组 SNP 系统发育树显示出高度相似性。溯源分析显示，沙门氏菌是通过新购入的鸡群传入该场的。由于该禽场工人多龄管理和流通，长期存在 XDR 肯塔基沙门氏菌 ST198 存在很大风险。因此，本研究首次报道了中国密集型家禽场中检测到的广泛耐药性肯塔基沙门氏菌 ST198。
