肠沙门氏菌是一种广泛存在的食源性致病菌,具有耐药性(AMR)。水禽是沙门氏菌传播的主要来源,但是关于水禽物种中沙门氏菌流行的系统研究很少。在这项研究中,从四川水禽样本中获得126株沙门氏菌(2018-2020年收集65株,2002-2005年收集61株),中国。他们的血清型,脉冲场凝胶电泳(PFGE)类型,系统检查了表型和基因型AMR谱。分离株分布于7个血清型,包括血清型肠炎(46.0%),波茨坦(27.8%),蒙得维的亚(7.9%),塞罗(6.3%),鼠伤寒(4.8%),Kottbus(4.0%)和Apeyeme(3.2%)。它们的PFGE特征多样;所有分离株分布在4组(截止值:60.0%)和20个簇(截止值:80.0%)中。此外,所有分离株都是多重耐药的,林可霉素的AMR率高(100.0%),利福平(100.0%),磺胺嘧啶(93.7%),红霉素(89.7%),环丙沙星(81.0%),观察到庆大霉素(75.4%)。最后,对49株分离株进行了全基因组测序,发现了各种各样的AMR基因,包括多个外排泵基因和特异性抗性基因。有趣的是,tet(A)/tet(B)和catII抗性基因仅在第一个收集期获得的分离株中检测到,而gyrA(S83F,在第二个收集期获得的分离株中检测到D87N和D87G)和gyrB(E466D)突变的频率较高,支持来自不同时期的分离株对四环素表现出不同的抗性模式的发现,氯霉素和萘啶酸。此外,检测到各种不相容的质粒复制子片段,包括Col440I,Col440II,IncFIB,INCFII,IncX1,IncX9,IncI1-I和IncI2,它们可能有助于AMR基因的水平传播并提供竞争优势。总之,我们证明了四川水禽养殖场中流行的沙门氏菌分离株表现出不同的血清型,多种AMR表型和基因型,AMR会随着时间的推移而改变,表明他们对公众健康的潜在风险。
Salmonella enterica is a widespread foodborne pathogen with concerning antimicrobial resistance (AMR).
Waterfowl are a major source of Salmonella transmission, but there are few systematic studies on Salmonella prevalence in
waterfowl species. In this study, 126 Salmonella isolates (65 collected in 2018-2020 and 61 collected in 2002-2005) were obtained from
waterfowl samples in Sichuan,
China. Their serotypes, pulsed-field gel electrophoresis (PFGE) types, and phenotypic and genotypic AMR profiles were systematically examined. The isolates were distributed in 7 serotypes, including serovars Enteritidis (46.0%), Potsdam (27.8%), Montevideo (7.9%), Cerro (6.3%), Typhimurium (4.8%), Kottbus (4.0%) and Apeyeme (3.2%). Their PFGE characteristics were diverse; all isolates were distributed in four groups (cutoff value: 60.0%) and 20 clusters (cutoff value: 80.0%). Moreover, all isolates were multidrug resistant, and high rates of AMR to lincomycin (100.0%), rifampicin (100.0%), sulfadiazine (93.7%), erythromycin (89.7%), ciprofloxacin (81.0%), and gentamicin (75.4%) were observed. Finally, 49 isolates were subjected to whole-genome sequencing, and a wide variety of AMR genes were found, including multiple efflux pump genes and specific resistance genes. Interestingly, the tet(A)/tet(B) and catII resistance genes were detected in only isolates obtained in the first collection period, while the gyrA (S83F, D87N and D87G) and gyrB (E466D) mutations were detected at higher frequencies in the isolates obtained in the second collection period, supporting the findings that isolates from different periods exhibited different patterns of resistance to tetracycline, chloramphenicol and nalidixic acid. In addition, various incompatible plasmid replicon fragments were detected, including Col440I, Col440II, IncFIB, IncFII, IncX1, IncX9, IncI1-I and IncI2, which may contribute to the horizontal transmission of AMR genes and provide competitive advantages. In summary, we demonstrated that the Salmonella isolates prevalent in Sichuan
waterfowl farms exhibited diverse serotypes, multiple AMR phenotypes and genotypes, and AMR changes over time, indicating their potential risks to public health.