Abstract
Metronidazole resistance among Helicobacter pylori strains has been related to alterations in gene products having metronidazole nitroreductase activities. RdxA and FrxA proteins are the two major contributing factors. In this investigation, the rdxA and frxA genes and their upstream regions were analyzed in 19 H. pylori isolates, 8 of which were metronidazole-sensitive (MIC ≤ 8 μg/mL) and 11 of which were metronidazole-resistant (MIC ≥ 8 μg/mL), as determined by the E-test. Among the metronidazole-resistant isolates, three contained both RdxA and FrxA proteins with premature truncation caused by gene nonsense mutations or frameshift mutations, while three contained only stop mutations in FrxA and two only in RdxA. Substitutions of amino acids occurred in other RdxA (5/6) and FrxA (4/5) proteins from metronidazole resistant isolates as compared with those from metronidazole-sensitive ones. All metronidazole-resistant isolates had alterations in RdxA and/or FrxA proteins. Moreover, the upstream regions (−1 to −35) of rdxA and frxA genes in some metronidazole-resistant isolates varied by nucleotide insertion and/or deletion or substitution. The patterns of variation in both genes and their upstream regions were highly diversified. Alterations in rdxA and frxA genes and their upstream regions may be involved in the development of metronidazole resistance in H. pylori.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.