北京市房山区腹泻病例分离副溶血性弧菌的分子流行病学特征

Molecular epidemiological characteristics of Vibrio Parahaemolyticus isolated from diarrhea patients in Fangshan District of Beijing

目的了解2016年北京市房山区腹泻病例副溶血性弧菌分离株的血清型、毒力基因、耐药性及PFGE分子分型特征。方法依照GB 4789.7-2013《食品安全国家标准食品微生物学检验副容血性弧菌检验》进行副溶血性弧菌生化鉴定,使用玻片血清凝集法进行血清分型,实时荧光聚合酶链式反应(PCR)测定毒力基因,微量肉汤稀释法进行药敏试验,脉冲场凝胶电泳进行分子分型及聚类分析。结果在检出的20株副溶血性弧菌中,O3:K6血清型占60%。所有菌株均携带tlh、tdh基因,trh基因的携带率为10%,tdh^+trh^-为优势基因型。抗生素敏感性结果显示,90%的菌株对至少1种抗生素耐药,其中多重耐药菌株5株。耐药率高的前3种抗生素分别是:头孢唑林(85%)、庆大霉素(75%)、氨苄西林(30%)。PFGE分型共得到10种带型,5株菌的PFGE带型一致,为优势带型。副溶血弧菌的血清型和PFGE带型之间具有高度的一致性。结论本地区副溶血性弧菌以tdh^+,trh^-的O3:K6型别为主,对头孢唑林、庆大霉素、氨苄西林等早期用药耐药率高,应慎重使用。

[Objective]To investigate the serotype,virulence gene,drug resistance and PFGE molecular typing characteristics of Vibrio parahaemolyticus isolated from diarrhea samples in Fangshan District of Beijing in 2016.[Methods] All the Vibrio parahaemolyticus strains were identified according to GB 4789.7-2013.Then the isolates were tested serotype by serological agglutination,virulence gene by real-time fluorescent PCR assay,drug sensitivity by broth micro dilution method,and molecular typing and cluster analysis by PFGE.[Results] Of the 20 V.parahaemolyticus detected,the serum type O3：K6 accounted for60%.All strains carried tlh and tdh genes,and 10% of the strains had trh gene.Genotype tdh^＋,trh^- was the dominant type.The result of antimicrobial susceptibility test showed that 90 % of the isolates were resistant to at least 1 antibiotic,including5 multidrug resistant isolates.Among these antibiotics,high rates of resistance were observed for cefazolin（85%）,gentamicin（75%） and ampicillin（30%）.Ten different types were obtained by PFGE,the dominant PFGE pattern included 5 isolates（same pattern）.There was a high consistency between the serotype and PFGE pattern of V.parahaemolyticus.[Conclusion ] Most V.parahaemolyticus strains isolated in Fangshan are genotype tdh^＋,trh^- and serotype O3：K6.High resistance to cefazolin,gentamicin and ampicillin required rational antibiotics use.