Molecular relationships of Helicobacter pylori strains in a family with gastroduodenal disease

Objective: Few studies have examined the genetic relationships of Helicobac ter pylori strains affecting family members. Our aim was to do so. Methods: We characterized H, pylori isolates obtained from members of a single fami ly presenting with various gastroduodenal diseases to examine H, pylori bac terial genetic similarity. Endoscopic evaluation with gastric mapping was p erformed on each individual to establish clinical and histological disease. Genomic DNA extracted from each H, pylori isolate was used to generate DNA fingerprints for each strain by REP-PCR, vacA genotypes and cagA presence were established by PCR, Results: Gastrointestinal diseases among the five members of this family included gastric adenocarcinoma in a 52-yr-old man t inder patient), gastric MALT-lymphoma in the 73-yr-old mother; intestinal m etaplasia (IV) and atrophic gastritis in the 48-yr-old brother; intestinal metaplasia (I-III) in the 47-yr-old brother, and a duodenal ulcer scar in t he 42-yr-old sister. REP-PCR DNA fingerprints of H, pylori isolates from th e index patient, his mother, and both of his brothers were identical or hig hly similar. By contrast, the H, pylori DNA fingerprint from the sister was markedly different from the H, pylori DNA fingerprints from the other fami ly members. All isolates had the genotype cagA-positive and vacA slb/ml mos aic genotype, Conclusions: The DNA fingerprints of H, pylori strains obtain ed from members of this family with malignancy or premalignant histological disease were identical or highly similar and markedly different from the H , pylori DNA fingerprint from the sibling with duodenal ulcer disease. All H, pylori isolates within the family possessed genetic markers of enhanced virulence (presence of the cagA gene and vacA sl/ml mosaicism). In addition to host genetics and environmental factors, these findings suggest that in fection with genetically similar H, pylori strains is a significant factor in determining the clinical outcome of an infection with H, pylori, (Am J G astroenterol 1999;94:364-368. (C) 1999 by Am. Cell. of Gastroenterology).