The Study Of Distribution And Internalin Genes Profiles Of Listeria Monocytogenes Among Food Samples

Listeria monocytogenes is a kind of important zoonotic disease pathogens, which can cause persons, various livestocks and fowls serious diseases. Listeria monocytogenes has been considered zoonotic disease pathogens in all over the world since 1940s. From the public health point of view, Listeria monocytogenes as one of the most important food-borne pathogen, it has been paid much more attention of the people since 1990s.Many experts and scholars at home and abroad study the biological characteristics, detection technology, pathogenicity gene, virulence factors and epidemiological of Listeria monocytogenes.This paper isolated and identified Listeria monocytogenes by the first step of the physiologic and biochemical tests from 586 samples. 586 random samples from 9 sorts of resh meat, meat protucts, aquatic products, quick-frozen food, fruit, vegetables, raw milk, bean product, salted product were collected from supermarkets and peasant-trade mart. The total detectable rate of Listeria monocytogenes is 19.0%. The results show that the detectable rate of Listeria monocytogenes are higher. It expresses that pollution level of Listeria monocytogenes in Baoding and circumjacent area is taller. Studying distributing status of Listeria monocytogenes, it was discoverhed that the able rate of Listeria monocytogenes in resh meat samples was the highest (34.5%). The second rate is 30.7%, in salted product. It indicated that the probability of this bacterium to pollute resh meat and salted product were high and we should attach importance to quality problem of these products to avoid breaking out of food-borne diseases. It was very important to defend the pathogen.At present, Listeria monocytogenes internalin genes can be divided into 9 types (inlA, inlB, inlC, inlC2D, inlD, inlE, inlF, inlG and inlH) . According to announced literatures, inlA and inlB are in all of Listeria monocytogenes strains. inlC, inlC2D, inlD, inlE, inlF, inlG and inlH are in certain of Listeria monocytogenes strains. Owing to identifying them to genus certainly, these strains were identified by PCR with primers of inlA, inlB, inlC, inlC2D, inlD, inlE, inlF, inlG and inlH. They are special pathogenic genes of L.monocytogenes and these primers are synthesized according to primer sequences in announced literatures. Among 108 Listeria monocytogenes strains, 80 strans (74.1%) contains at least two of internalin genes. 74 strains (68.5%) contained inlA, 81 strains (75.0%) contained inlB, 59 strains (54.6%) contained both inlA and inlB.It is needed that the pollution conditions of Listeria monocytogenes in crowd, livestocks and foods as well as epidemiologic conditions of this pathogen are further investigated for the supervision of Listeria monocytogenes, the examination of explosion and spread as well as tracking to pollrter to providing basis.