江苏地区肉鸡屠宰链弯曲菌分离菌株毒力基因分布及分子分型研究

Study on the virulence gene distribution and molecular typing of Campylobacter isolates from broiler slaughter chain in Jiangsu Province

目的了解江苏地区肉鸡屠宰生产链中弯曲菌分离菌株毒力基因分布及不同环节分离菌株遗传相关性。方法利用特异性引物对肉鸡屠宰过程不同环节分离所得的96株弯曲菌分离菌株的10种致病相关毒力基因进行聚合酶链式反应(polymera sechainre action,PCR)检测,应用多位点序列分型(multilocus sequence typing,MLST)方法对分离菌株进行分子分型研究,通过与弯曲菌MLST数据库比对获得各株菌等位基因值、序列型(sequence types,STs)及克隆复合体。结果96株分离菌株中,flaA、cadF和cdtB毒力基因携带率均为100%,其次为cdtC、iam和cdtA毒力基因,携带率较高,分别为96.9%、86.5%和84.4%,另外3个毒力基因flhA、virB11、ciaB携带率均较低,分别为25.0%、15.6%、11.5%;格林-巴利综合症相关毒力基因wlaN在所有菌株中均无检出。MLST分型结果显示,96株弯曲菌可分为10个STs,其中2个为新STs,形成1种优势克隆复合体CC828(56株)和4种未定义的克隆复合体,表现为较低的遗传多样性。结论肉鸡屠宰生产链中弯曲菌毒力基因分布广泛,不同环节弯曲菌分离菌株遗传多样性较低,表明弯曲菌在肉鸡屠宰生产链中存在交叉污染。

Objective To investigate the virulence gene distribution and genetic correlation of Campylobacter isolates from different links in broiler slaughter chain in Jiangsu Province.Methods Ten kinds of pathogenic virulence genes of 96 strains of Campylobacter isolated from different links of broiler slaughtering process were detected by polymerase chain reaction(PCR)with specific primers,the molecular typing of these isolates was investigated by multilocus sequence typing(MLST),the allelic values,sequence types(STs)and clonal complexes of each strain were obtained by comparing with the MLST database of Campylobacter.Results Among the 96 strains of isolates,the carrying rates of virulence genes flaA、cadF and cdtB were 100%,followed by the virulence genes cdtC、iam and cdtA,the carrying rates were higher,which of 96.9%,86.5%and 84.4%,respectively,the carrying rates of flhA、virB11、ciaB were low,which of 25.0%、15.6%、11.5%,respectively.The gene wlaN resulting in an increased risk for Guillain-Barrésyndrome in patients was not detected in all strains.MLST genotyping showed that a total of 10 STs,including 2 novel STs,were observed from the 96 strains of isolates,1 kinds of dominant clonal complex CC828(56 strains)and 4 kinds of undefined clonal complexes were formed,showing low genetic diversity.Conclusion The virulence genes of Campylobacter isolates are widely distributed in the broiler slaughter chain,and the genetic diversities of Campylobacter isolates at different stages are low,indicating that there is cross-contamination of Campylobacter in broiler slaughter chain.