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目的了解上海地区大流行副溶血性弧菌(VP)大流行菌株血清型分布及分子特征。方法对2010—2012年分离自腹泻患者和食品中的VP菌株进行血清分型,以GS-PCR辨别大流行株,以PCR检测菌株的毒力基因tdh、trh和大流行株分子标识f237噬菌体orf8基因,以PFGE分型来分析菌株间的遗传关系。结果 1 136株VP可分为52个血清型(群),其中64.5%的菌株GS-PCR阳性,判定为大流行菌株,其血清型有11种,主要集中于O3∶K6(76.8%)、O4∶K68(9.4%)、O1∶K25(6.8%)、O1∶K36(4.5%)4种血清型。相对于非流行菌株,O10∶K60、O3∶K3、O1∶K33三种血清型的菌株其PFGE图谱与已报道的大流行株更为接近,为新检测到的大流行血清型变种。大流行产毒株中仅能检测到tdh基因,未检测到trh基因,94.3%的大流行菌株携带噬菌体f237的orf8基因,但有5.7%的大流行株orf8基因缺失。相同血清型的大流行菌株其PFGE图谱存在差异,且orf8基因的携带与否不能以PFGE进行区分。结论上海地区VP大流行菌株血清型相对集中,且不断有新的血清型变种出现。从PFGE图谱的差异和orf8基因的携带与否上来看,大流行菌株仍在演变。
Objective To understand the serotype distribution and molecular characteristics of the pandemic strains of Vibrio parahaemolyticus (VP) in Shanghai. Methods The serotypes of VP strains isolated from diarrhea patients and foodstuffs from 2010 to 2012 were analyzed by serological methods. The pandemic strains were identified by GS-PCR. The virulence genes tdh, trh and the molecular markers of pandemic strains f237 phage orf8 Gene, PFGE genotyping to analyze the genetic relationship between strains. RESULTS: One hundred and sixty-six VP strains were divided into 52 serogroups. Among them, 64.5% strains were positive for GS-PCR and were classified as pandemic strains. The serotypes of 11 strains were 11 and mainly concentrated in O3: K6 (76.8%), O4: K68 (9.4%), O1: K25 (6.8%), O1: K36 (4.5%). Compared with the non-endemic strains, the strains of O10: K60, O3: K3, O1: K33 have more similar PFGE patterns than the reported pandemic strains, and are newly detected pandemic serotypes. Only the tdh gene was detected in the pandemic toxigenic strains, no trh gene was detected, 94.3% of the pandemic strains carried the orf8 gene of the phage f237, but 5.7% of the pandemic orf8 genes were deleted. PFGE profiles of the same serotypes of the pandemic strains are different, and orf8 gene can not be carried by the PFGE to distinguish. Conclusion The serotypes of VP pandemic strains in Shanghai are relatively concentrated, and new serotypes are continuously emerging. The pandemic strains are still evolving from the differences in PFGE patterns and the orfac genes.