Helicobacter pylori intrafamilial infections: Change in source of infection of a child from father to mother after eradication therapy

Biopsy specimens of the antrum and corpus were obtained from four Helicobac ter pylori-infected members of a family and from the same boy (son 1) in wh om the infection reappeared after simultaneous successful eradication treat ment of three family members, excluding the mother. A total of 18 to 60 H, pylori isolates were obtained from each specimen and subjected to rRNA gene restriction pattern analysis. The father's isolates and the initial isolat es from son 1 showed the same HindIII type, which was divided into three Ha eIII subtypes, Isolates from the mother and a brother (son 2) and posttreat ment isolates from son 1 showed a distinct HindIII type (with one minor sub type), which was divided into six HaeIII subtypes. All subtypes of the init ial isolates from son 1 were present in the father's isolates, and all subt ypes of the posttreatment isolates from son 1 were present in the mother's isolates but not in son 2's, Electron microscopic analysis of the biopsy sp ecimens demonstrated extremely high levels of H. pylori colonization in the father's gastric mucosa, H. pylori adherence with a ruffle formation was a lso demonstrated. The findings suggest that son 1 was infected initially wi th the H, pylori strain of the father and son 2 was infected with the H, py lori strain of the mother and that after eradication therapy son 1 was rein fected with the H,pylori strain of the mother, who did not undergo eradicat ion therapy.