Association of Metronidazole Resistance and Natural Competence in Helicobacter pylori

Publisher Website
Google Scholar
Abstract
To study whether the capability of horizontal DNA transfer is associated with metronidazole resistance in Helicobacter pylori , a total of 81 clinical isolates were tested for MICs of metronidazole (MTZ). The MIC assays were performed by using the E-test and reconfirmed by the agar dilution method. Natural competence assays were performed by transferring a chloramphenicol acetyltransferase cassette and a 23S rRNA gene from a clarithromycin-resistant strain (with an A-to-G mutation at nucleotide 2143) by using natural transformation. Of the 81 isolates, 65 (80.2%) were naturally competent while 16 were not. Among the 65 naturally competent strains, 39 (60%) were highly resistant to MTZ (MICs, >32 μg/ml) while only 2 of 16 (12.5%) noncompetent strains were highly MTZ resistant ( P , <0.001). Therefore, there is an association between natural competence and MTZ resistance.