Analysis of Genetic Relatedness between Gastric and Oral Helicobacter pylori in Patients with Early Gastric Cancer Using Multilocus Sequence Typing.

The oral cavity is the second most colonized site of after the stomach. This study aimed to compare the genetic relatedness between gastric and oral in Japanese patients with early gastric cancer through multilocus sequence typing (MLST) analysis using eight housekeeping genes. Gastric biopsy specimens and oral samples were collected from 21 patients with a fecal antigen test positive for . The number of allelic profiles ranged from zero to eight since the yield of DNA was small even when the nested PCR was performed. MLST analysis revealed that only one patient had a matching oral and gastric genotype, suggesting that different genotypes of inhabit the oral cavity and gastric mucosa. The phylogenetic analysis showed that oral in six patients was similar to gastric , implying that the two strains are related but not of the same origin, and those strains may be infected on separate occasions. It is necessary to establish a culture method for oral to elucidate whether the oral cavity acts as the source of gastric infection, as our analysis was based on a limited number of allele sequences.