深圳地区不同来源空肠弯曲菌毒力基因分布及分子分型研究

目的 了解深圳地区市售禽类食品和腹泻病人中分离的空肠弯曲菌毒力基因分布及其分子分型情况。方法 根据特异性引物,运用聚合酶链式反应(PCR)检测空肠弯曲菌4种毒力基因(cdtB,cadF,flaA,virB11),应用脉冲场凝胶电泳分型技术(PFGE)对空肠弯曲菌分离株进行分子分型。结果 3种毒力基因在禽类食品分离株(5株)和腹泻病人分离株(5株)的分布情况一致,均携带cdtB和cadF,但均未检出virB11,两种来源菌株flaA的检出情况分别为3/5和2/5; PFGE聚类分析图谱显示,10株空肠弯曲菌经Sam I 酶切后可分别产生5～9条DNA条带的PFGE带型,其中食品株与病人株之间部分存在高度同源,同源性达到85%以上,但高度同源的菌株之间携带flaA毒力基因的分布不同。结论 深圳地区空肠弯曲菌存在cadF,cdtB,flaA等3种毒力基因,不同来源菌株之间同时具备多样性和同源性,提示空肠弯曲菌腹泻病人的感染来源可能与受污染的禽类食品密切相关,为该地区食源性空肠弯曲菌腹泻病提供基础性资料和依据。

Study on the Differences of Virulence Genesand Molecular Typing in Campylobacter Jejuni Isolatesfrom Poultry Products and Diarrhea Patients in Shenzhen

Objective To understand the differences of virulence genes and molecular typing in Campylobacter jejuni isolates from poultry products and diarrhea patients in Shenzhen.Methods According to specific primers,four virulence genes(cdtB,cadF,flaA,virB11)of C.jejuni were detected by polymerase chain reaction(PCR).Molecular typing for C.jejuni strains was performed by Pulsed-field gel electrophoresis(PFGE).Results There were no differences of gene distribution(cdtB+,cadF+,virB11-)between isolates from poultry products and diarrhea patients.Two virulence genes of cdtB and cadF were found in all of ten C.jejuni strains lacking virB11.The carriage rate of flaA in food-borne isolates(3/5)was higher than those in patient isolates(2/5).In the PFGE map,the clustering analysis of C.jejuni strains showed thata total of 5 to 9 DNA bands were observed in ten strains through the digestion of Sam I.There was high homology(above 85%)between food-borne isolates and patients isolates,but the distribution of flaA in these highly homologous strainswas different.Conclusion So far,C.jejuni strainswith cdtB,cadF and flaA were present in Shenzhen,and showed high diversityand homology.This implies that the occurrence of diarrhea in patients with C.jejuni was associated with the contaminated poultry products by this pathogen.Their findings can provide basic data and evidences about diarrheal disease caused by food-borne C.jejuni for the local region.