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The rdxA Gene Plays A More Major Role Than frxA Gene Mutation in High‐level Metronidazole Resistance of Helicobacter pylori in Taiwan
Author(s) -
Yang YaoJong,
Wu JiunnJong,
Sheu BorShyang,
Kao AiWen,
Huang AyHuey
Publication year - 2004
Publication title -
helicobacter
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.206
H-Index - 79
eISSN - 1523-5378
pISSN - 1083-4389
DOI - 10.1111/j.1083-4389.2004.00270.x
Subject(s) - biology , mutation , helicobacter pylori , gene , metronidazole , genetics , microbiology and biotechnology , antibiotics
Background. Metronidazole‐resistant H. pylori associating with mutations of rdxA or frxA is still a debated topic. This study investigates whether rdxA and frxA mutations of H. pylori accounted for the high MIC value (≥ 64 µg/ml) of metronidazole (Mtz). Material and Methods. From 126 clinical H. pylori isolates, we examined 14 Mtz‐sensitive, 18 Mtz‐resistant H. pylori , and eight pairs of Mtz‐sensitive and Mtz‐resistant colonies simultaneously present within a single gastric biopsy. The paired strains from one single biopsy were proven identical by PCR‐RFLP. MICs of Mtz were checked by the E ‐test and agar dilution method. The mutations of rdxA and frxA sequencing were matched with the Mtz‐susceptible ATCC 26695 and J99. Results. There were 89% (16/18) of Mtz‐resistant isolates with mutation of RdxA. Half of the 14 Mtz‐sensitive strains, all without mutation of RdxA, still contained truncation of FrxA. Within the paired isolates from a single biopsy, rdxA mutation (86%) was more common than frxA mutation (43%) in those isolates with high‐level Mtz‐resistant H. pylori . RdxA truncation was more prevalent in Mtz‐resistant strains with high MICs than in those with low to moderate MICs (75% vs. 20%, p = .01, OR: 12, 95% CI: 1.8–81.7). Conclusion. Mutations in the rdxA gene rather than the frxA gene generally determine a high MIC level of Mtz‐resistant H. pylori in Taiwan.