Helicobacter pylori antibiotic resistance in Iran.
OBJECTIVE
To examine the frequency of antibiotic resistance in Iranian Helicobacter pylori (H pylori) strains isolated from two major hospitals in Tehran.


METHODS
Examination of antibiotic resistance was performed on 120 strains by modified disc diffusion test and PCR-RFLP methods. In addition, in order to identify the possible causes of the therapeutic failure in Iran, we also determined the resistance of these strains to the most commonly used antibiotics (metronidazole, amoxicillin, and tetracycline) by modified disc diffusion test.


RESULTS
According to modified disc diffusion test, 1.6% of the studied strains were resistant to amoxicillin, 16.7% to clarithromycin, 57.5% to metronidazole, and there was no resistance to tetracycline. Of the clarithromycin resistant strains, 73.68% had the A2143G mutation in the 23S rRNA gene, 21.05% A2142C, and 5.26% A2142G. None of the sensitive strains were positive for any of the three point mutations. Of the metronidazole resistant strains, deletion in rdxA gene was studied and detected in only 6 (5%) of the antibiogram-based resistant strains. None of the metronidazole sensitive strains possessed rdxA gene deletion.


CONCLUSIONS
These data show that despite the fact that clarithromycin has not yet been introduced to the Iranian drug market as a generic drug, nearly 20% rate of resistance alerts toward the frequency of macrolide resistance strains, which may be due to the widespread prescription of erythromycin in Iran. rdxA gene inactivation, if present in Iranian H pylori strains, may be due to other genetic defects rather than gene deletion.
Mohammadi
Marjan
M
Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran. marjan@institute.pasteur.ac.ir
Doroud
Delaram
D
Mohajerani
Nazanin
N
Massarrat
Sadegh
S
D000328:Adult; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005260:Female; D017353:Gene Deletion; D005798:Genes, Bacterial; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000382:microbiology*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D007492:Iran; D008297:Male; D008875:Middle Aged; D009601:Nitroreductases / Q000235:genetics; D012329:RNA, Bacterial / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012338:RNA, Ribosomal, 23S; D009601:Nitroreductases; C476646:RdxA protein, Helicobacter pylori