云南地区鸭源沙门菌的分离鉴定及耐药性和毒力基因分析

【背景】沙门菌是一种重要的食源性人兽共患病原菌，可引起多种食源性疾病。【目的】了解云南地区鸭源沙门菌病的流行现状、耐药现象及毒力基因携带等基本情况。【方法】无菌采集云南各地区病死鸭肝脏样品169份进行沙门菌分离，对分离株进行血清分型鉴定、药敏及相关耐药基因、毒力基因筛查。【结果】分离到鸭源沙门菌48株，分离率为28.40%，鉴定出3种血清型，其中肠炎沙门菌为优势血清型。分离株对青霉素G、林可霉素、克林霉素和利福平的耐药率达100%，每株菌至少对3类6种及以上的抗生素耐药，单株最高可耐14种，产生了22种耐药谱型。共检出耐药基因5种，bla_TEM和tetB检出率分别为27.08%和22.92%，tetA、sul2和EBC的检出率较低。毒力基因共检出10种，其中，SPI-1(avrA)、SPI-3(mgtC)、SPI-4(siiD)、SPI-5(sopB)和bcfC检出率均高达100%，SPI-2(ssaQ)、spvB、spvC、pefA和stn的检出率均达60%以上，cdtB未检出。【结论】云南地区鸭源沙门菌主要流行血清型为肠炎沙门菌，耐药性及多重耐药情况严重，耐药机制复杂，耐药基因与耐药表型符合率低，毒力基因检出率较高。研究结果可为云南地区鸭群沙门菌病的防控和净化提供参考。

Isolation and identification of Salmonella from ducks in Yunnan province and analysis of its antimicrobial resistance and virulence gene

Background] Salmonella is an important food-borne zoonotic pathogen that causes a variety of food-borne diseases among humans and animals. Objective] This research was to investigate the prevalence, antimicrobial resistance and virulence gene of salmonellosis in ducks in Yunnan province. Methods] A total of 169 liver samples of dead ducks from various regions in Yunnan province were collected for Salmonella isolation, and the isolated strains were subjected to serotyping, drug sensitivity test, and screening for related drug resistance genes and virulence genes. Results] Forty-eight Salmonella strains were isolated, with the isolation rate being 28.40%. Three serotypes were discovered, of which Salmonella enteritidis was the dominant one. The isolates had a 100% resistance to penicillin G, lincomycin, clindamycin and rifampicin. Each was resistant to at least 6 kinds of 3 categories of antibiotics, and there was one strain resisting as more as 14 kinds, resulting in 22 drug resistance spectra. A total of 5 resistance genes were detected, of which the detection rates of bla_TEM and tetB were 27.08% and 22.92%, respectively, while those of tetA, sul2 and EBC were low. Ten virulence genes were detected, and the detection rates of SPI-1 (avrA), SPI-3 (mgtC), SPI-4 (siiD), SPI-5 (sopB) and bcfC were all 100%, whereas those of SPI-2 ssaQ, spvB, spvC, pefA and stn reached above 60%, with cdtB undetected. Conclusion] S. enteritidis was the dominant serotype in ducks in Yunnan province, with severe drug resistance and multi-drug resistance, and the mechanism of drug resistance was complex. The coincidence rate of resistance gene and phenotype was low, while the detection rate of virulence gene was high. These results provide a reference for the prevention, control and eradication of salmonellosis in ducks in Yunnan province.