Clarithromycin resistance and 23S rRNA mutations in Helicobacter pylori isolates in Iran

To determine the 23S rRNA point mutations in clarithromycin resistance of Helicobacter pylori strains isolated from southwest, Iran. This was a cross-sectional survey, which was done on 263 patients who referred to endoscopy department of Shehrekord university of medical sciences. According to gram stain, urease, catalase, oxidase and polymerase chain reaction (PCR) H. pylori identified. Standard National Committee for Clinical Laboratory Standard (NCCLS) method used for assessment of clarithromycin resistance. Specific primers and restriction enzymes BsaI and MboII by PCR-RFLP were used for analysis of A2143G and A2142G mutations. So for the detection of A2142C, specific primers and PCR method were used. 84 strains of H. pylori (31.94%) determined by PCR method. Of 19 (22.62%) clarithromycin resistant strains 13 (68.40%), 3 (15.78%), 2 (10.52%) had A2143G, A2142G, A2142C respectively and one unknown mutation in 23S rRNA gene. Because of considerable resistance to clarithromycin, direct diagnosis of this mutation by molecular approach in other parts of the country is necessary. Key words: