Original Articles
Copyright ©The Author(s) 1998. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 15, 1998; 4(5): 385-387
Published online Oct 15, 1998. doi: 10.3748/wjg.v4.i5.385
Helicobacter pylori acquistion of metronidazole resistance by natural transformation in vitro
Jie-Song Hua, Peng-Yuan Zheng, Keng Fong Teo, Mar Mar Khin, Bow Ho
Jie-Song Hua, Peng-Yuan Zheng, Keng Fong Teo, Bow Ho, Department of Microbiology, National University of Singapore, Lower Kent Ridge Road, Singapore 119074, Singapore
Mar Mar Khin, Temasek Ploytechnic, Singapore
Jie-Song Hua, male, born on 16-11-1961 in Shanghai, B Med, M Med and M Sc, having 20 papers published.
Author contributions: All authors contributed equally to the work.
Correspondence to: Dr. Jie-Song Hua, Department of Microbiology, National University of Singapore, Lower Kent Ridge Road, Singapore 119074, Singapore.michuajs@nus.edu.sg
Telephone: +65-8743285
Received: August 8, 1998
Revised: September 16, 1998
Accepted: October 2, 1998
Published online: October 15, 1998
Abstract

AIM: To study whether Helicobacter pylori is naturally transformable.

METHODS: Transformation was performed in BHI broth supplemented with horse serum and yeast extract. Genomic DNA extracted from a metronidazole resistant H.pylori strain was added to H. pylori broth culture. The mixture was incubated at microaerophilic atmosphere. The DNA-treated cells were plated on blood agar containing 8 mg/L metronidazole to select for transformants. Sterile distilled water was used as a negative DNA control. The DNA profiles of transformants were compared with that of their parent strains by randomly amplified polymorphic DNA (RAPD) fingerprinting.

RESULTS: Transformation of H. pylori with DNA from a metronidazole resistant strain as a marker was demonstrated. Out of the 12 strains of H. pylori tested, 9 (75%) strains were found to be transformable. The transformation frequencies ranged from 3.4 × 10-6 to 2.4 × 10-4. By RAPD, DNA fingerprints of the transformants and their parent strains showed no change in DNA profiles though transformants were all resistant to metronidazole as compared with their metronidazole-sensitive parent strains.

CONCLUSION: Helicobacter pylori is naturally transformable which might be one of the ways that H. pylori develops resistance to metronidazole.

Keywords: Helicobacter pylori; metronidazole; drug resistance, microbial; transformation, bacterial