RESUMEN
AIM: To evaluate whether the Helicobacter pylori status of the patient's spouse plays a role in reinfection after eradication success, and to assess the possibility of transmission of H. pylori among partners by using molecular methods. METHODS: We studied prospectively 120 patients in whom H. pylori had been eradicated. Endoscopy with biopsies and a 13C-urea breath test were performed 1 month after completing therapy. The breath test was repeated in all patients at 6 and 12 months. At the 1-year follow-up visit (or before if reinfection occurred), a breath test was also performed on the patient's partner. Samples for the molecular study included gastric biopsies from patients and gastric content obtained by the string test from partners. The heterogeneity of ureC was studied by enzymatic digestion with MseI and HhaI enzymes of a polymerase chain reaction (PCR) product of 1179 bp belonging to the ureC gene, and different band patterns were generated after electrophoresis. RESULTS: Four reinfections were diagnosed at 6 months, and four were diagnosed from 6 to 12 months (incidence 6.8% per patient-year). Seven of eight (87%) of the reinfected patients' spouses were infected, but H. pylori infection of spouses was also frequent (76%) among non-reinfected patients. In the multivariate analysis, age of the patient (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.87 to 0.99, P < 0.05), delta(13)CO(2) value after therapy (OR 2.51, 95% CI 1.14 to 5, P < 0.05), and therapy regimen (OR 6.23, 95% CI 1.25 to 31, P < 0.05) were the only variables that correlated with H. pylori recurrence. However, family variables (H. pylori status of spouse, breath test value of spouse, length of time couple had lived together, number of children living at home, household density) did not correlate with recurrences. Thus, the OR for the H. pylori status of spouse (adjusted by age, delta(13)CO(2) and therapy) was 2.93 (95% CI 0.29 to 29, P > 0.05). H. pylori recurrence occurred in seven of 92 (7.6%) patients when the spouse was infected (95% CI 3.7% to 15%), and in one of 28 (3.6%) patients when the spouse was H. pylori-negative (95% CI 0.6% to 18%) (P > 0.05; however, the power of this comparison was < 20%). Therefore, even if the spouse was infected, 92.4% of patients will remain uninfected 1 year after H. pylori eradication. Three reinfected patients (at 1 year) and their partners (also infected) agreed to have the endoscopy and string test performed, respectively. The molecular study revealed that H. pylori strains involved were different in all cases. CONCLUSION: Recurrence of H. pylori infection seems to be relatively infrequent, even if the patient's spouse is H. pylori-positive. The molecular study demonstrated that the strains in reinfected patients and their partners are different, suggesting that the patient's partner does not act as a reservoir for H. pylori reinfection.