Conservation of Helicobacter pylori genotypes in different ethnic groups in Houston, Texas.

This study was concerned with whether the Helicobacter pylori strains circulating among ethnic groups living in the same region differ. The polymerase chain reactions to genotype (cagA, vacA, and iceA) H. pylori isolates from healthy volunteers from 4 ethnic groups (black, n=35; white Hispanic, n=31; whites, n=30; Vietnamese, n=29) residing in Houston were examined. The Vietnamese volunteers had the "East Asian"-type cagA 3' repeat region structure, and the others had the "non-Asian" type. The most common genotypes were delineated as follows: blacks and Hispanics, cagA+, vacA s1b-m1, and iceA2; whites, cagA+, vacA s1a-m2, and iceA2; and Vietnamese, cagA+, vacA s1c-m2, and iceA2. Two Hispanic families were also examined. H. pylori isolates from the children and their mothers had the same genotype and were different from those associated with the children's fathers or brothers-in-law. Conservation of an H. pylori genotype within ethnic groups over the course of generations will prove useful for epidemiological study of the coevolution of humans and H. pylori.