DIFFERENTIATION OF HELICOBACTER-PYLORI STRAINS DIRECTLY FROM GASTRIC BIOPSY SPECIMENS BY PCR-BASED RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISMANALYSIS WITHOUT CULTURE

Recent studies have shown the usefulness of PCR-based restriction frag ment length polymorphism (RFLP) analysis for differentiating Helicobac ter pylori strains isolated by culture, For this study, a PCR-based RF LP assay was developed for directly typing H. pylori strains from gast ric biopsy specimens. Nineteen gastric biopsy specimens obtained from patients undergoing endoscopy for gastrointestinal complaints were cul tured for isolation of H. pylori. Genomic DNA preparations from these gastric biopsy specimens and the corresponding H. pylori isolates were tested by our PCR-based RFLP assay. The 1,179-bp H. pylori DNA fragme nts amplified by the PCR assay were digested with the restriction enzy mes HhaI, MboI, and AluI and analyzed by agarose gel electrophoresis. HhaI, MboI, and AluI digestion produced 11, 10, and 6 distinguishable digestion patterns, respectively, from the 19 H. pylori isolates teste d and generated Id, 11, and 6 different patterns, respectively, from t he 19 gastric biopsy specimens. The patterns from 13 of the 19 gastric biopsy specimens matched those of the H. pylori isolates from the cor responding patients, The patter ns from the remaining six biopsy speci mens appeared to represent infection by two strains of H. pylori; the pattern of one strain was identical to that of the isolate from the co rresponding patient. By combining all the restriction enzyme digestion patterns obtained by using HhaI, MboI, and AluI, we observed 19 disti nct RFLP patterns from the 19 specimens. The results suggest that the PCR-based RFLP analysis method may be useful as a primary technique to identify and distinguish H. pylori strains directly from gastric biop sy specimens without culture of the organisms.