DNA Fingerprinting of Helicobacter pylori Isolated form Patients with Peptic Ulcer

Hong, Su Jin; Park, Yong Soon; Lee, Young Hong; Cho, Young Deok; Kim, Jin Oh; Bong, Hyung Keun; Cho, Joo Young; Lee, Joon Seong; Lee, Moon Sung; Kim, Yun Soo; Hwang, Seong Gyu; Shim, Chan Sup; Hwang, Seung Duk; Lee, Hi Bahl

Abstract

BACKGROUND/AIMS: The gastric pathogen Helicobacter pylori establishes long-term chronic infection that can lead to gastritis, peptic ulcers, and gastric cancer. However, little is known about the source and route of infection of this organism, and the mechanism of pathogenicity is only now beginning to be unravelled. Urease might allow the survival of the bacteria in an acidic environment, a prerequisite for colonization. H. pylori is cytotoxic to cultured human gastric epithelial cells and this toxicity is due in part to ammonia produced by hydrolysis of urea. We performed this study to evalute the usefulness of DNA fingerprinting of urease genes as a sensitive epidemiological tool for the typing of H. pylori clinical isolates.
METHODS
Clinical isolates of H. pylori were obtained by biopsy from 18 patients with peptic ulcer at the time of endoscopic examination. Biopsy tissues were cultured under microaerophilic conditions. DNA of H. pylori were extracted for PCR amplification. This study used the polymerase chain reaction(PCR) to amplify the urease structural subunit genes, ureA and ureB, which, when digested with restriction endonucleases, allow the differentiation of patterns on 1.5% agarose gels.
RESULTS
The 2.4 kb PCR products amplified and subjected to Hae III restriction endonuclease digestion produced 11 distinct patterns on agarose gels, with five patterns occurring within two or three isolates.
CONCLUSIONS
The urease genes of H. pylori had genetic heterogeneity, but it could be of considerable tool for epidemiological studies. Moreover the method is useful for studies of relation between H. pylori induced diseases and different strains because unique pattems were shown in two or three isolates. In conclusion, DNA fingerprinting of H. pylori could be available for epidemiological studies of H. pylori infections and for clinical applications.