[Pathogenic gene analysis of Listeria isolated from foods].

In 1996-1997, Listeria in foods from 12 provinces of China were detected by using the national standard examination method GB 4789.30-94 (routine traditional methods). Twenty four strains Listeria monocytogenes and 141 strains Listeria were identified by biochemical procedures and animal toxicity experiment. Polymerase Chain Reaction(PCR) was used to amplify two specific DNA fragments(719 bp and 446 bp) of listeriolysin O and internalin genes with two pairs of primer--Hly1-2 and Inl1-2, respectively. The experiment results showed that 57 strains contained only internalin, 27 strains contained both internalin and listeriolysin O from the pathogenic genes of isolated strains.