摘要AIM: To evaluate the prevalence of Helicobacter pylori ( H. Pylori) babA2, babB and a recombinant gene between babA2 and babB ( babA2/B), and their role in the development of atrophic gastritis in Costa Rican and Japanese clinical isolates.METHODS: A total of 95 continuous H. Pylori-positive Costa Rican (41 males and 54 females; mean age,50.65 years; SD, ± 13.04 years) and 95 continuous H. Pylori-positive Japanese (50 males and 45 females;mean age, 63.43; SD, ± 13.21 years) patients underwent upper endoscopy from October 2005 to July 2006. They were enrolled for the polymerase chain reaction (PCR)-based genotyping of the H. Pylori babA2,babB and babA2/B genes. Statistical analysis was performed using the χ~2 test and the Fisher’s exact probability test and multivariate analysis was performed by logistic regression adjusting for gender and age. P <0.05 was regarded as statistically significant.RESULTS: The PCR-based genotyping of 95 Costa Rican and 95 Japanese isolates showed a higher prevalence of babA2 in Japan (96.8%) than in Costa Rica (73.7%), while that of babA2/B was higher in Costa Rica (11.6%) than in Japan (1.1%). In Costa Rican isolates only, babA2 was significantly associated with atrophic gastritis ( P = 0.01).CONCLUSION: These results suggest that the status of babA2 and babA2/B shows geographic differences,and that babA2 has clinical relevance in Costa Rica.