副溶血弧菌SHJLA株的分离鉴定及致病性分析

ISOLATION, IDENTIFICATION AND PATHOGENICITY OF VIBRIO PARAHAEMOLYTICUS STRAIN SHJLA

副溶血性弧菌(Vibrio parahaemolyticus)是海洋环境中常见的食源性致病菌。本研究从对虾中分离出1株细菌SHJLA,在TCBS和弧菌显色培养基上分别显示典型的蓝绿色和紫红色的菌落,且其生理生化特性具有典型副溶血弧菌的特性。以SHJLA菌株的基因组为模板,检测副溶血弧菌种特异性基因(tlh、toxR、groEL)均为阳性,gyrB基因序列分析表明SHJLA与副溶血弧菌的亲缘关系最近,同源性达98%～100%;检测副溶血弧菌主要毒力相关基因tdh和T3SS2(VopC2和vcrD2)均为阳性。该菌的神奈川溶血实验为阳性,对小鼠的半数致死量(LD50)为4.8×108cfu/mL。结合SHJLA菌株的形态、生理生化、种特异性基因的检测、gyrB基因序列分析、毒力相关基因的检测以及小鼠半数致死量的测定结果,确定SHJLA是一株携带毒力基因的副溶血弧菌。

Vibrio Parahaemolyticus is a common food-bome pathogen in marine environment. In the present study, a bacterial strain was isolated from a shrimp sample and identified it as Vibrio parahaemolyticus strain SHJLA by its morphological, physiological and biochemical characteristics. The SHJLA strain formed blue-green colonies on TCBS and aubergine colonies on vibrio ehromogenic medium. Its physiological and biochemical characteristics also met typical features of V parabacmolyticus. The SHJLA strain posseessed specific genes （tlb, toxR, groEL） of V. parahaemolyticus. Sequence analysis of gyrB gene showed that SHJLA strain shared 98%-100% identity to published V. parahaemolyticus data. In addition, important virulence related genes （tdb and T3SS2） of V. parahaemolyticus were also found in SHJLA strain. The SHJLA strain showed β hemolytic reaction and was KP positive. When mice were intraperitioneally injected with SHJLA strain, it had high virulence as measured by the median lethal dose （LD50） of 4.8×10^8 cfu/mL.