polymorphism & RFLP

Helicobacter pylori colonize the gastric mucosa, related with different gastro-duodenal diseases and the clinical outcome linked to these diseases has been associated with pathogen virulence genes and their polymorphism. The aim of the study is to detect Helicobacter pyloricagA gene and to investigate the distribution of their genotypes in the patients with gastroduodenal symptoms. Total 51 patients were enrolled in the study on the basis of clinical and endoscopic findings. Written informed consent was obtained from each patient prior to the endoscopic procedure and collection of gastric biopsy specimens. Histopathological examination was done for detection of H. pylori in tissue specimens. The H. pylori histopathology positive specimens are considered as Helicobacter pylori positive and PCR were done for cagA detection and the positive specimens further tested by RFLP to detect the cagA polymorphism. Among the histopathology positive H. pylori cases 90% were positive for cagA gene by PCR and almost 100% cagA were β genotype by PCR-RFLP. No α genotype of cagA was found. Mean age of the patients were 46.9 ± 14.2 years starting from 22to 76 years. Out of 51 patients 39(76.47%) were male and 23.52% were female. According to the age group distribution, 22 (43.13%) were in 41-60 years age group and 39.21%and 17.64% were in 20-40 years and 61-80 years age group respectively. Among the 09 cagA positive cases 55.6% are in the 41-60 years age group and most (66.6%) of the cagA positive cases found in male patients. Significant percentage (33.3 and 50) of cagA was found among the patients suffering from melena and hematemesis. The result of the present study by PCR-RFLP pattern analysis revealed only β genotype for H. pylori cagA positive strains, which were typical genotypes in strains from Western countries. Therefore, it seems that the evaluation of genetic diversity in H. pylori-associated cagA gene can be attributable to the colonial relationship and epidemiology of H. pylori in defined population.