Delaram Doroud - Biotechnology Research Center, Pasteur Institute of Iran
Nazanin Mohajerani - Biotechnology Research Center, Pasteur Institute of Iran
Sadegh Massarrat - Gastroenterology Department, Shariati Hospital
Marjan Mohammadi - Biotechnology Research Center, Pasteur Institute of Iran

Metronidazole and clarithromycin are usually used for Hp eradication therapy with good rates of. Resistance to one or both of these antibiotics reduces the effectiveness of the designed therapy. The rate of resistance to these antibiotics among Iranian Hp strains was determined according to modified disc diffusion test and PCR-RFLP methods. According to modified disc diffusion test, 16.7% of the studied strains were resistant to clarithromycin and 57.5% to metronidazole. Of the Clarithromycin resistant strains, 73.68% had the A2143G mutation in the 23srRNA 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. These data show that despite the fact that molecular methods believe to be consistent and time-consuming methods, they are not reliable for the detection of metronidazloe resistance in a highly infected population as the results of microbial and molecular tests for resistance to this antibiotic are in accordance. The scenario is opposite for clarithromycin, if a diagnostic laboratory is mobilized to the molecular assay equipments these methods are preferred.

Hp, clarithromycin, metronidazole, molecular assays, resistance, Iran