蜂蜜中蜡样芽胞杆菌的分离鉴定及其毒力基因的检测

Separation identification of Bacillus cereus in honey and detection of their virulence genes

目的了解蜂蜜中蜡样芽胞杆菌的污染情况及其毒力基因的分布情况。方法采用国家标准GB 4789.14—2014中MPN计数法对抽检蜂蜜样品的蜡样芽胞杆菌计数,并利用PCR法对分离的16株蜡样芽胞杆菌的毒力基因进行检测。结果蜂蜜中蜡样芽胞杆菌的检出率为41.0%,分离的16株蜡样芽胞杆菌中至少检出2种毒力基因,非溶血性肠毒素NHE基因nheA、nheB和nheC检出率最高,同时携带这3种基因的有5株。菌株BC-1和BC-9携带的毒力基因最多,均为7种,同时携带溶血素BL基因hblA、hblC和hblD,还同时携带基因nhe B、nheC、bceT和cytK,有较强的毒性。呕吐毒素基因cer、ces及EM1均未检出。结论蜂蜜中检出了携带毒力基因的蜡样芽胞杆菌,且毒力基因的检出率较高,表明在含蜂蜜的食品、保健品和药品中存在一定的生物安全风险。

Objective To investigate the contamination of Bacillus cereus in honey and the distribution of different virulence genes.Methods The MPN method of national standard GB 4789.14—2014 was used to count Bacillus cereus in honey samples,and the virulence genes of 16 isolated Bacillus cereus strains were detected by PCR.Results The detection rate of Bacillus cereus from honey samples was 41.0%,and at least 2 virulence genes were detected in the 16 isolated Bacillus cereus strains.The non-hemolytic enterotoxin NHE genes(nhe,nhe B and nhe C)have the highest detection rate,and there were 5 strains carrying the three genes.Seven kinds of virulence genes were found in the strain BC-1 and BC-9:haemolysin BL genes(hbl A,hbl C and hbl D),the non-haemolytic enterotoxin NHE genes(nhe B and nhe C,except nhe A),enterotoxin T gene(bce T)and cytotoxin K gene(cyt K).They might have strong toxicity.Emetic toxin genes ces,cer and EM1 were not detected.Conclusion Bacillus cereus carrying virulence genes was detected in honey,and the detection rates of the virulence genes were high,so there would be some risks in the foods,health products and drugs containing honey.