Rapid genomic diversification of Helicobacter pylori

Helicobacter pylori was cultured from antrum and corpus gastric biopsies from 65 patients originating from two separate groups: (i) a geographically linked group and (ii) a geographically nonlinked group. Genomic DNA was recovered from the clinical isolates and subjected to restriction fragment length polymorphism (RFLP) analysis after digestion with DraI. Southern blots were probed with the oligonucleotide (GTG)5, the riboprobe pKK3535, and the cagA gene probe pMC3. (GTG)5 and cagA DNA fingerprints and ribopatterns suggested that most of the patients were infected with their own unique strain; however, some were infected with multiple strains. Minor genomic differences were detected in many antrum/corpus sample pairs (clonal variants), suggesting rapid evolutionary change in domains detected by (GTG)5. The high degree of genomic diversity detected by (GTG)5 may reflect structural versatility of these domains. The genomic diversity indicates that infection by H. pylori in a defined community does not appear to be limited to certain RFLP types.