Evaluation of frxA and rdxA gene mutations in clinical metronidazole resistance Helicobacter pylori isolates
- Author:
Somi, M.H.
;
Milani, M.
- Publication Type:Journal Article
- From:Tropical Biomedicine
2017;34(2):346-351
- CountryMalaysia
- Language:English
-
Abstract:
Metronidazole resistance is an important factor related to failure in the treatment
of Helicobacter pylori. The mutation in the rdxA and frxA genes is the most important cause
of resistance to metronidazole. Since the resistance rate of metronidazole is high in our
region, we decided to assess the frequency of these mutations among H. pylori clinical
isolates. Antral gastric biopsy specimens were cultured and minimal inhibitory concentrations
(MICs) of metronidazole were determined by the E-test method. The rdxA and frxA genes
were amplified in all isolates through the use of PCR with the specific primers. PCR products
were purified for sequencing. The resultant sequences were compared with the wild type
reference sequences to find any possible mutations. According to our findings, the rate of
metronidazole resistance was 77%, with the MICs ranging from 0.25-1 μg/ml for metronidazole-
sensitive group and from 16-256 μg/ml for resistance group. H. pylori isolates containing a
single mutation in rdxA or frxA genes demonstrated a low MIC (8-16 μg/ml), while those
containing mutations in both genes showed a higher MIC (32-256 μg/ml). In this study, all
resistant H. pylori isolates contained single or multiple nucleotide substitutions in the
mentioned genes. Nevertheless, no nucleotide substitutions were found in the sensitive
clinical isolates. The results of our study showed that the mutations in rdxA are mostly
related to metronidazole resistance, and mutations in frxA are able to enhance H. pylori
resistance.
- Full text:P020170616396201587134.pdf
