一蜡样芽胞杆菌食物中毒分离株的表型与基因型  

Phenotype and genotype analysis of one Bacillus cereus isolate from an emetic food poisoning case

作　　者：周帼萍[1] Niels Bohse Hendriksen Kai Bester 刘勇[1] 杨祖顺[3] 

机构地区：[1]武汉轻工大学生物与制药工程学院,湖北武汉430023 [2]丹麦奥胡斯大学环境科学系 [3]云南省疾病预防控制中心,云南昆明650022

出　　处：《中国食品卫生杂志》2015年第1期10-14,共5页Chinese Journal of Food Hygiene

基　　金：中国-丹麦政府间科技合作项目([2010]329);湖北省教育厅科学研究计划项目中青年项目(Q20111703)

摘　　要：目的对2003年发生在云南的一起蜡样芽胞杆菌呕吐型食物中毒案例中的分离株YN0303进行表型和基因型分析研究。方法采用16S r DNA序列分析和16S/23S r DNA ITS特征图谱分析结合形态、生理生化和基因型进行菌种鉴定;PCR检测呕吐毒素和肠毒素合成相关基因,高效液相和质谱联用(HPLC-MS)化学定量分析呕吐毒素合成情况,测试部分生理生化特性和生长温度范围,进行了pan C分型和多位点序列分型(multilocus sequence typing,MLST)。结果确认了该菌株确为蜡样芽胞杆菌Bacillus cereus,虽然该食物中毒是典型的呕吐型案例,但是发现该分离株呕吐毒素相关合成基因ces呈阴性,呕吐毒素化学定量分析结果为阴性;其生理生化特性(水杨苷发酵、淀粉水解和溶血特性)与典型呕吐型菌株也不相同。pan C分型并非呕吐型蜡样芽胞杆菌所属的Ⅲ型,而是属于细胞毒性强的IV型,而且其肠毒素基因hbl、nhe和cyt K2也均呈阳性;多位点序列分析显示该菌是一个新型别ST753,是区域性相对独立进化菌株。结论在该呕吐型食物中毒案例中可能有多个蜡样芽胞杆菌参与,该分离株YN0303并非主要致病株—呕吐型菌株,但可能作为细胞毒性强的菌株参与了共感染。Objective This study investigated the phenotypic and genotypic characteristics of YN0303,an isolate from a food poisoning case occurred in Yunnan Province in 2003. Methods The strain was identified by 16 S r DNA and 16 S /23 S r DNA ITS analysis,together with morphology,biochemical and gene analysis. Toxic gene profiles,pan C analysis,mutilocus sequence typing and high performance liquid chromatography-mass spectrometry（ HPLC-MS） analysis were further applied. Results YN0303 was confirmed to be Bacillus cereus. Although it’s an isolate from a typical food poisoning case,it was negative for cereulide-producing related ces gene and no cereulide was detected in HPLC-MS quantitative analysis,while it was positive for entero-toxigenic genes such as hbl,nhe,and cyt K2. It’s also different from typical emetic B. cereus in biochemical tests. It belonged to cytotoxic IV group,while emetic strains should belong to Ⅲgroup. YN0303 forms a new ST in mutilocus sequence typing analysis,which was an independent branch in phylogeny tree. Conclusion More than one B. cereus strain involved in this emetic food poisoning case,and YN0303 was not the main pathogenic strain. But as a cytotoxic strain,it might be involved in co-infection.

关 键 词：蜡样芽胞杆菌 呕吐型食物中毒 多位点序列分析 食物中毒 食品安全 食源性致病菌 

分 类 号：R155.3[医药卫生—营养与食品卫生学]