The Effect Of Hp Infection On Gut Microbiota And The Relation Between Hp Infection And Colorectal Cancer

[Background and Objective] The change of gut microbiota plays an important role in the digestive diseases, but the relation between Helicobacter pylori (Hp) infection and gut microbiota has not been reported. This paper mainly studies the effect of Hp infection on gut microbiota and the relationship between Hp infection and colorectal cancer (including colorectal neoplasm) in different continents or economic development.[Materials and Methods] 1) The fresh stool specimens were collected from normal persons and patients with Hp infection. Hp, E. coli 0157, lactobacillus, enterococcus and bifidobacterium were amplified by PCR.2) The diversity of gut microbiota was identified using PCR-DGGE.3) Published case-control studies dealing with the correlation of colorectal cancer associated with Hp infection were retrieved from PubMed, EMBASE, High Wire Press, Ovid, Medline and EBSCO. Meta-analysis was performed by using RevMan 5.3 software. We selected the OR and 95%CI as indicators of the analysis according to different continents (Asia, Europe, and America) and economic development (developed country and developing country).[Results] 1) The expression of Hp was not found in Hp negative group, consistent with the 13C breath test. The expression of bifidobacterium, lactobacillus, and enterococcus in Hp negative group were higher than Hp infection group. There was no E. coli 0157 in Hp negative group.2) Through PCR-DGGE, the number of 16S rDNA in the V3 zone in different groups is different, and the number of each lane is different, too. There has significant differences in the number of bands and the gray value between the two groups (P<0.05).3) A total of 23 studies dealing with the correlation of colorectal cancer associated with Hp infection, and there was a total sample of 182,561 patients, including 88,378 cases in Hp positive group and 94,183 cases in Hp negative group, and the results of meat-analysis showed the OR was 1.42 (95%CI:1.38-1.46). According to the geographic differences, the correlation was low in Asian [OR 1.29 (95%CI 1.13～1.48)], and the correlation was highest in America [OR1.44 (95%CI 1.39～1.48)]. According to the economic development, the correlation was low in developing countries [(OR 1.17(95%CI 1.01～1.37)], and the correlation was higher in developed countries [(OR 1.43(95%CI 1.39～1.47)].[Conclusion] (1) The numbers of bifidobacterium, lactobacillus, and enterococcus were changed caused by Hp infection. And it would be increase the chance of E.coli 0157 infection. It means that Hp infection can influence the distribution of gut microbiota.2) The results of DGGE show that there is a different between Hp normal and positive group, and the diversity of the former is more than the latter. The number of colonies is different among the same group. It means that there is the diversity in different people among the same group.3) Hp infection is a risk factor for colorectal cancer. Meanwhile, different continents and economic development were the impacts on the relation between Hp infection and colorectal cancer.