副溶血弧菌海产品分离株及临床分离株的多位点序列分型

Multilocus sequence typing of Vibrio parahaemolyticus seafood and clinical isolates

选取毒力调控基因toxRS和看家基因gyrB、recA作为靶基因,对浙江沿海地区40株副溶血弧菌海产品分离株与8株临床分离株进行多位点序列分型。toxRS的多态性位点比例(10.2%)虽低于gyrB(12.0%)与recA(25.4%),但与gyrB均可分辨出最多的序列型(38),具有最强的分辨力(0.986)。3个基因串联后可分出44个序列型,分辨力达0.994。副溶血弧菌分离株呈现出较大的多样性。各地的海产品分离株分布于A群、B群,而临床分离株则主要集中于A群;C群仅包括1个临床分离株。其中临床分离株C2、C5、C7与海产品分离株F24属于同一个序列型,由此可推测该序列型在地域上分布较为广泛并可引起人发生胃肠炎等。因而副溶血弧菌所引起的对公共卫生的潜在风险性不容忽视。

Vibrio parahaemolyticus is an important foodborne pathogen widespread in littoral; In this study, 40 seafood isolates and 8 clinical isolates from Zhejiang province were selected for multilocus sequence typing （MLST） based on virulence gene toxRS, housekeeping genes gyrB and recA. Although the ratio of polymorphic sites of toxRS （10.2%） was lower than those of gyrB （12.0%） and recA （25.4%）, toxRS had more discriminative power than that of targeting the housekeeping genes. Concatenation of the three genes was able to recognize 44 sequence types with discrimination index （DI） of 0. 994. The results revealed a diversity of V. parahaemolyticus isolates. All seafood isolates belonged to groups A and B, while the majority of clinical isolates fell into group A except one isolate classified into group C. More strikingly, clinical isolates C2, C5 and C7 together with Zhejiang seafood isolate F24 belonged to the same sequence type, which is probably geographically widespread and can result in gastroenteritis in humans. Therefore, threats against public health posed by V. parahaemolyticus contamination in foods should not be neglected.