H. pylori infection has been associated with a low socioeconomic status and crowding conditions. H. pylori strains, Cag-A/Vac-A, may be used to identify intra-familial contamination.

Aims: To identify H. pylori strains, Cag-A/Vac-A, within household members of symptomatic children who were histologically identified with H. Pylori infection.

Methods: Serum samples of all household members of ten H. pylori seropositive children were prospectively collected. H. pylori seropositivity was identified by HM-CAP ELISA kit or FlexSure rapid test. H. pylori strains, Cag-A/Vac-A, were identified by Immuno-probing Western blot(Helico blot 2.0; GeneLabs Diagnostics, S.A).

Results: Ten families with a total of 32 household, non-patient members, were identified. Twenty memberes (62%) had experience nonspecific abdominal symptoms in the past. 28/32 (88%) were seropositive for H. pylori infection. Twelve (37%) were Cag-A positive, 9 (28%) were Vac-A positive, 8(25%) were positive for both strains, and 14 (44%) were negative for both strains. Identical H. pylori strain between patient and all household members was found in 4 (40%) families. Identity of H. pylori strains in more than 50% of household members was found in 4 (40%) families, and complete dissociation in H. pylori strains between patient and household members was found in 2(20%) families.

Conclusion: (1) H. pylori infection is commonly found within household members. (2) The significant identity of H. pylori strains within family members, suggests an intra familiar contamination. (3) We recommend that similar to streptococcal infection, household members of children with H. pylori infection should be serologically screened to prevent future contamination.