Analysis The Genetic Diversity Of Helicobacter Pylori VacA And CagA Isolated From Hexi Corridor

Objective1. To detect the genetic diversity and evolutionary features of vac A and cagA of Helicobacter pylori (Hp) isolated from Hexi Corridor, in order to explore the reasons of high incidence of gastric disease in the local.2. To explore the genotype distribution of intermediate (i) region genotype of Hp vacA isolated from Hexi Corridor, in order to study the specific information about Hp biological features, pathogenic mechanism and to develop strategies to explore vaccine to control Hp infection.Methods1. The gastric mucosa samples from the patients in regional hospitals in Hexi Corridor were cultured under micro aerobic condition and the bacteria were identified by the conony features, morphology, rapid urease, and oxidase and catalase test.2.30Hp strains vac A and cagA whole sequence from Hexi Corridor were amplified by PCR and sequenced.3. Hp vac A and cagA sequences were analyzed by using NCBI database and MEGA software in order to build the genetic evolutionary trees to compare similarities and evolutionary distance of vac A and cagA between the isolated strains and the reported strains of the world, and to discuss the relationship between the vac A and cagA genetic features and clinicopathological types.4.61isolated Hp strains vac A intermediate (i) region genotype were amplified by PCR. The relationship between vac A i region genotype and clinicopathological types, genders and ages were analyzed.Results1.22and26Hp samples were successfully amplified and sequenced the whole sequence of vacA and cagA respectively from30Hp strains isolated from3local hospitals in Hexi Corridor. 2. After phylogenetic analysis showed that the evolutionary of Up vac A in Hexi corridor was more close to Asian strains like SNT49India, F30Japan,F32.Japan strains than the strains from other continents.The average evolutionary distance was2.53747128. There exsited a gathered phenomenon of Hp vac A in the evolutionary tree in Hexi corridor.3. After phylogenetic analysis showed that the evolutionary of Hp cagA in Hexi corridor was more close to Asian strains like F57Japan,F32Japan strains than the strains from other continents.The average evolutionary distance was4.2434595460. There exsited a gathered phenomenon of Hp cugA in the evolutionary tree in Hexi corridor.4. The trend of Hp vacA and cagA in evolutionary tree had no significant correlation with clinical and pathological features.5. The constituent ratio of61Hp isolated from55patients vac A i1and i2genotype was86.89%(53/61) and13.11(8/61) respectively. The infection rate of vacA i1genotype was significantly higher than i2in age groups under60and41years, same sex groups, and same clinicopathological type groups (P<0.05). The infection rate of the same vac A i1and i2genotype had no significant difference in different sex groups, age groups under60years, and the different clinicopathological types (P>0.05). The infection rate of vacA i2genotype in age group of over60years was significantly higher than that under60years (P<0.05).Conclusion1. Hp vac A and cagA in genetic evolutionary in Hexi Corridor is more close with Asiar strains.2. Hp cagA has more genetic evolutionary variability than vacA in Hexi Corridor.3. There exist local aggregation of Hp vac A and cagA on genetic evolutionary in Hexi Corridor. The evolutionary trend of Hp vacA and cagA in Hexi Corridor has no significant correlation with clinicopathological types.4. Hp vac A i region genotype from Hexi Corridor are all positive, and i1type is the main genotype.5. The distribution of vacA i region genotype have no association with the types of disease and ages. The infection of vacA i2region genotype has an increased trend with ages.