应用聚合酶链反应检测食品中肠毒素大肠杆菌

Detection of Enterotoxin Escherichia Coli in Food by polymerized Enzyme Chain Reaction

应用聚合酶链反应（PCR）对食品样品中肠毒素大肠杆菌（ETEC）热敏性肠毒素（LT）和耐热肠毒素（ST）基因进行扩增，两对引物从ETEC的LT和ST基因中分别扩增出314bP和237bP的DNA片段，均能与相应的LT和ST基因探针杂交；酶切分析表明，不同菌株扩增的片段为均一的LT基因和ST基因的PCR产物；对128份食品样品中ETEC的污染情况进行了测定，三种基因型（LT，ST，LTST）的ETEC从样品中鉴定出。

Two different sets of oligonucleotide primers were used to amplify the heat-labile (LT)and heat -stable (ST)enterotoxin genes of Enterotoxin Eschebehia coli (ETEC) 314bp and 237bp DNA fragments were amplified by LT,and ST primers from LT and ST genes, respectively. The amplified fragments were analyzed by restriction endonuclease and southern hybridization. Three types of ETEC strains corresponding to LT. ST and LTST gene type were distinguished by the same procedure of polymerized enzyme chain reaction (PCR)using the mixture of the two sets of primers,128 specimens from different foods were examined by PCR.