Y-022. Analysis of Helicobacter pylori Virulence Factor Genotypes and Intestinal Parasites in Fecal Specimens of Healthy Subjects

T. Sasaki1, R. Izurieta2,3, B. H. Kwa2, F. Valles2, E. Estevez3, E. Velasco3, F. Barrera4, A. Saldana5, J. Calzada5, M. Utsumi1, S. Fujimoto1, A. Kimoto1, Y. Fukuda1, I. Hirai1, Y. Yamamoto1;
1Osaka Univ. Graduate Sch. of Med., Osaka, JAPAN, 2Univ. of South Florida, Tampa, FL, 3Central Univ. of Ecuador, Quito, ECUADOR, 4MoPH, Quito, ECUADOR, 5ICGES, Panama, PANAMA.

Background: Helicobacter pylori is the causative agent for the most prevalent infectious disease known to occur in humans. In addition, it is thought that infection with these bacteria may directly link to the development of gastric cancer. Current studies indicate that the genotype of virulence factors for H. pylori may be critical to the development of gastric cancer. It is also proposed that concurrent infection with certain enteric parasites may reduce the incidence of gastric cancer associated with H. pylori by modifying the immune response. However, epidemiological analysis of such factors in the development of gastric cancer is not well studied. In particular, the genotype of cagA virulence factor of H. pylori in healthy subjects is not known. Therefore, in the present study, epidemiological analysis of H. pylori virulence factor genotypes and intestinal parasites in fecal specimens of healthy subjects was conducted. Methods: Fecal specimens were collected along with interviews from healthy subjects in Ecuador and Panama following IRB protocols in both countries. The specimens were analyzed for H. pylori prevalence by immunological detection of bacterial antigen using a commercial kit (Testmate Rapid Pylori Antigen, BD, Tokyo, Japan), parasite prevalence by microscopy, and cagA status of H. pylori by PCR assay. Results: Total of 165 fecal specimens obtained from healthy subjects was analyzed. The prevalence of H. pylori in Ecuador and Panama was 72% and 54%, respectively. The intestinal parasite prevalence of Ecuador and Panama was 42% and 54%, respectively. In contrast, the prevalence of helminth infection, which is thought to modulate the immune status to reduce virulence of H. pylori, in Ecuador was much lower than that in Panama. The prevalence of East Asian genotype of cagA positive H. pylori in Ecuador was higher than that in Panama. Conclusion: Since the stomach cancer death rate in Ecuador is higher than in Panama, the results obtained in this study may suggest a possible contribution of these factors to the development of gastric cancer associated with H. pylori.