ERIC-PCR和Sau-PCR对单增李斯特菌分型稳定性研究

为了研究肠杆菌间重复序列-聚合酶链式反应(ERIC-PCR)和Sau-PCR两种现代分子分型方法对单增李斯特菌(LM)分型的稳定性,取分离自广州市菜市场、超市及厦门某食品加工厂不同食品来源的5株单增李斯特菌进行实验,分别将这5株单增李斯特菌株进行室温放置培养和传代培养,提取室温放置培养24 h、48 h、和72 h及传代培养至第5代、10代、15代和20代的基因组DNA,然后同时进行ERIC-PCR和Sau-PCR分型,观察随着放置时间延长及传代次数增加其指纹图谱的变化。结果显示,5株单增李斯特菌在室温放置培养及传代培养后除部分条带发生缺失外均未出现条带增加现象,整体条带变化不大,两种分型方法的同源性分别在92%和94%以上,表明ERIC-PCR和Sau-PCR两种分型方法在室温放置培养72 h和传代培养20代内对单增李斯特菌分型相对比较稳定,具有流行病学意义。

Stability of ERIC-PCR and Sau-PCR Techniques on Listeria monocytogenes Typing

To evaluate the stability of enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and Sau-PCR for typing of Listeria monocytogenes (LM), five isolates of LM from a local vegetable market in Guangzhou and a food processing plant in Xiamen were cultured. DNA was extracted from the cultures incubated at room temperature after 24, 48, and 72 h. In addition, DNA was extracted from the 5th, 10th, 15th, and 20th subcultures. ERIC-PCR and Sau-PCR were then used for typing and changes in fingerprint diagrams with time and increase in the number of generations in subculture were determined. The results indicated that apart from some missing bands, there were no additional bands after room-temperature culture and subculture. However, there were minor changes in the overall band appearance. The homology of ERIC-PCR and Sau-PCR results was higher than 92% and 94%, respectively, indicating that the two typing methods were stable and had epidemiological significance for typing of LM cultures incubated for less than 72 h and 20 generations.