摘要
目的调查广州地区食品中产气荚膜梭菌的污染水平及菌型分布。方法参照国家标准方法进行产气荚膜梭菌的分离鉴定,采用针对产气荚梭菌α、β、ε、ι、CPE和β2六种毒素的基因cpa、cpb、etx、iA、cpe和cpb2序列的6对特异性引物,用多重PCR方法对分离菌株进行基因分型鉴定。同时用产气荚膜梭菌A型参照株NCTC64609作为阳性对照。结果从142份食品中分离到21株产气荚膜梭菌,以冷冻肉的带菌率最高,为19.6%;鲜肉和速冻肉饺分别为12.2%和11.9%。经多重PCR方法鉴定,均扩增出预期大小为324bp的cpa基因片段的特异性条带,未扩增出针对cpb、etx和iA基因的特异性条带,证实均为A型产气荚膜梭菌。携带β2毒素基因的产气荚膜梭菌共19株(占总分离株的90.4%),其中1株为肠毒素基因阳性的A型菌株。结论初步调查表明广州地区食品中存在可致人食物中毒的肠毒素阳性A型产气荚膜梭菌污染,为进一步建立广州地区食品中及与食物中毒有关的厌氧菌分子分型数据库奠定了基础。
Objective To determine the prevalence and genotypes of Clostridium perfringens （C.perfringens） isolated from food samples in Guangzhou area. Method The C.perfringens were isolated from the food samples and further identified by biochemical tests according to National Standard of Microbiological Examination of Food Hygiene. The C.perfringens virulence genes cpa, cpb, etx, iA, cpe and cpb2, which is emcoding the virulence factors α、β、ε、ι, CPE and β2, respectively, were ampLified by multiplex PCR using specific primers to determine the genotyes of the isolated strains. C.perfringens reference strain NCTC64609 was included as the positive control. Result 21 strains of C.perfringens were isolated from 142 food samples;frozen meat having the highest C.perfringens positive rate of 19.6%, followed by fresh meat and frozen meat dumping of 12.2% and 11.9%, respectively. Multiplex PCR results demonstrated that all strains had the expected specific band of 324 bp cpa gene fragment of C.perfringens, but specific cpb, etx and iA gene fragment did not appear. Thus all these strains can be classified as type A of C.perfringens. There were 19 strains of C.perfringens that carried the β2 virulence gene （accounting for 90.4%）and one strain was proved to be C.perfringens enterotoxin gene positive. Conclusion This preliminary investigation showed that contamination exists in food in Guangzhou area by type A C.perfringens carrying β2 toxin and which were CPE-positive.
出处
《热带医学杂志》
CAS
2006年第6期682-684,690,共4页
Journal of Tropical Medicine
基金
广东省医学科学技术研究基金(No.WSTJJ20040915440105660227242)
广州市科技计划基金(No.2005J1-C0191)
