蜡样芽胞杆菌食物中毒分离株分子分型分析

Molecular typing of Bacillus cereus strains isolated from food

目的建立蜡样芽胞杆菌的分子分型方法,应用于蜡样芽胞杆菌食物中毒的溯源研究。方法从2000-2009年广东省深圳市食物中毒暴发和散发病例的临床分离株中挑选47株蜡样芽孢杆菌进行鉴定及生化分型,同时进行vrrA基因PCR扩增并对产物进行测序,用Bio-edit和MEGA软件对DNA序列进行同源性比较。结果传统生化分型:47株蜡样芽胞杆菌中有5株菌不能分型,其余42株菌可分为2型、10型和4型,其中2型16株,占34.04%,10型16株,占34.04%,4型10株,占21.28%;分子分型:47株菌可分为13个基因型MT1-MT13,其中MT13型19株,占40.43%,MT1型8株,占17.02%,MT10型4株,占8.51%。结论 vrrA基因作为蜡样芽胞杆菌分子分型的一个多态性遗传标记,可用于蜡样芽胞杆菌DNA分子分型研究,对食物中毒溯源有重要意义。

Objective To develop a molecular typing method of Bacillus cereus strain for tracing Bacillus cereus-induced food poisoning.Methods Totally 48 Bacillus cereus strains were isolated from outbreak or sporadic cases of food poisoning from 2000 through 2009 for the biological identification and biochemical typing.vrrA gene was amplified by PCR and sequenced.The results were analyzed with Bio-edit and MEGA analysis software.Results Forty-two strains were typed into 3 types known as type 2（34.04%）,type 10（34.04%）,and type 4（21.28%）,while other 5 strains could not be typed by biochemical typing.Forty-seven strains were typed into 13 genotypes by molecular typing.Among the strains typed,MT13 is the main type（19 strains,40.43%）;8（17.02%） strains are MT1,and 4（8.51%） strains are MT10.ConclusionvrrA gene could be used in the investigation of Bacillus cereus DNA molecular typing and could be considered as a polymorphism genetic marker of Bacillus cereus.