Introduction: We postulated that the oro-oral route of transmission between spouses could be an important route of transmission of Helicobacter pylori.
Aims: To estimate the prevalence of different genotypes of H. pylori as distinguished by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in our local population, and to compare the genotypes of H. pylori isolated from patients and their spouses.
Methods: Gastric biopsies were obtained from 183 dyspeptic patients during endoscopy. PCR for H. pylori was carried out using the uceC gene for amplification, and PCR products were digested further for RFLP analysis using the enzyme MboI. Spouses of H. pylori-positive index cases were screened for the infection using serological testing; if found to be positive serologically, endoscopy and gastric biopsies were performed for genotypic study of the micro-organism. For couples with indistinguishable H. pylori strain on RFLP with restriction endonuclease MboI, the process of RFLP was repeated with digestion of the PCR products using restriction endonuclease HhaI.
Results: We established our PCR technique to be 89.5% sensitive and 95.5% specific. Eighty-nine subjects were found to be H. pylori positive by PCR, and eight different genotypic strains were found according to our RFLP analysis. Two genotypes accounted for 80.8% of the cases. Sixteen of 31 spouses tested serologically for H. pylori were positive. All 13 spouses who agreed to undergo endoscopy were PCR positive for H. pylori. Five couples shared indistinguishable H. pylori genotypes, but this strain was also the commonest genotype in our local population, as based on RFLP with restriction endonuclease MboI. Further RFLP on the PCR products on these five couples using restriction endonucleases HhaI showed that the H. pylori isolated from these five couples were of different strains.
Conclusion: The oro-oral route of transmission between spouses is unlikely to be an important mode for H. pylori infection.