副溶血弧菌SHJLA株的分离鉴定及致病性分析

摘要

副溶血性弧菌（Vibrioparahaemolyticus）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4.8×108 cfu/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。%VibrioParahaemolyticus is a common food-borne 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 chromogenic medium. Its physiological and biochemical characteristics also met typical features of V.parahaemolyticus. The SHJLA strain posseessed specific genes (tlh、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 (tdh and T3SS2) of V. parahaemolyticus were also found in SHJLA strain. The SHJLA strain showedβhemolytic 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 4.8×108 cfu/mL.