Genome Analysis of Helicobacter pylor by Pulsed-field Gel Electrophoresis

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The authors investigated the molecular epidemiology of Helicobacter pylori using genotyping with pulsed-field gel electrophoresis. In the first year of the investigation, the authors attempted to apply this technique to evaluation of the efficacy of eradication therapy.The following three strains of samples were used : 1) 77 strains from different patients, 2) strains from before and after eradication therapy in 4 cases, and 3) strains from the pyloric vestibule and greater curvature of the gastric body in 18 cases. Of the 77 strains in 1), 75 displayed a different genotype and only two had the same genotype. These two strains were collected from two patients who received an endoscopic examination at the same division with 10 days of one another, and cross infection via health-care physicians, the endoscopic device, or tools was suspected. The genotype pre- and post- eradication therapy in one case from B was different, which suggested re-infection. In three other cases, the genotype p … More re- and post-therapy was the same or a high degree of similarity was found ; the authors determined that the eradication was incomplete. Of the 18 cases in 3), the genotype was the same in 15. In 3 cases - a male in his 50s, a female in her 60s, and a male in his 60's - different genotypes were observed and existence of multi- infection with more than two clones of H. pylori was established. The infection by multiple clones suggests that repeated infection was received with each opportunity for infection and is thought to be one reason for the increase in the rate of infection with advancing age.After the second year, the authors investigated the correlation between sensitivity patterns of H. pylori for the three drugs AMPC, CAM, and MNZ and the efficacy of eradication therapy. The rate of increased resistance to each drug was almost identical to that in reports from other institutes. Half of the cases with failed eradication were infected with a primary resistant strain. One strain in the strains from the gastric vestibule and greater curvature of the gastric body in 3 cases displayed a different sensitivity pattern in two locations, and it established the existence of multi-infection with more than two clones with differing eradication drug sensitivity.These results demonstrated that combined use of genotyping with pulsed-field gel electrophoresis and sensitivity examination is helpful for evaluation of efficacy of eradication therapy. Less