CLUSTER-ANALYSIS OF HELICOBACTER-PYLORI GENOMIC DNA FINGERPRINTS SUGGESTS GASTRODUODENAL DISEASE-SPECIFIC ASSOCIATIONS

Background: Helicobacter pylori infection is now accepted as the most common cause of chronic active gastritis and peptic ulcer disease. The etiologies of many infectious diseases have been attributed to specif ic or clonal strains of bacterial pathogens. Polymerase chain reaction (PCR) amplification of DNA between repetitive DNA sequences, REP elem ents (REP-PCR), has been utilized to generate DNA fingerprints to exam ine similarity among strains within a bacterial species. Methods: Geno mic DNA from H. pylori isolates obtained from 70 individuals (39 duode nal ulcers and 31 simple gastritis) was PCR-amplified using consensus probes to repetitive DNA elements. The H. pylori DNA fingerprints were analyzed for similarity and correlated with disease presentation usin g the NTSYS-pc computer program. Results: Each H. pylori strain had a distinct DNA fingerprint except for two pairs. Single-colony DNA finge rprints of H. pylori from the same patient were identical, suggesting that each patient harbors a single strain. Computer-assisted cluster a nalysis of the REP-PCR DNA fingerprints showed two large clusters of i solates, one associated with simple gastritis and the other with duode nal ulcer disease. Conclusions: Cluster analysis of REP-PCR DNP, finge rprints of H. pylori strains suggests that duodenal ulcer isolates, as a group, are more similar to one another and different from gastritis isolates. These results suggest that disease-specific strains may exi st.