Epidemiology and Infection

Molecular epidemiology of Helicobacter pylori: separation of H. pylori from East Asian and non-Asian countries

Y. YAMAOKA a1a2c1, M. S. OSATO a1, A. R. SEPULVEDA a1, O. GUTIERREZ a3, N. FIGURA a4, J. G. KIM a5, T. KODAMA a2, K. KASHIMA a2 and D. Y. GRAHAM a1
a1 VA Medical Center and Baylor College of Medicine, Houston, TX, USA
a2 Third Department of Internal Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
a3 Universidad Nacional de Colombia, Bogota, Colombia
a4 Institute of Internal Medicine, University of Siena, Siena, Italy
a5 Guro Hospital, Korea University College of Medicine, Seoul, Korea


The predominant H. pylori strain circulating among geographic locations differs with regard to the genomic structure. This study determined whether structural subtypes of the cagA 3′ repeat region could be used to identify the population of origin of H. pylori isolates. We examined 600 cagA-positive H. pylori (Colombia, 100; USA, 100; France, 100; Canada, 20; Italy, 20; Korea, 100; Japan, 100; Hong Kong, 20; Taiwan, 20; Vietnam, 20). The cagA 3′ region was amplified by PCR using primers specific to Japanese and Western 3′ cagA gene sequences. PCR using Japanese cagA primers resulted in PCR products in 99·6% of strains from East Asia but no non-Asian strains. Conversely, PCR using Western cagA primers resulted in amplicons in 100% of non-Asian strains, and only one from East Asia. cagA genotyping is useful for molecular epidemiological studies as strains can be completely separated by differences in the cagA 3′ region.

(Accepted October 5 1999)

c1 Author for correspondence: Veterans Affairs Medical Center (111D), 2002 Holcombe Blvd, Houston, TX 77030 USA.