and Aim: Increased resistance to the macrolides is probably due to excessive and inappropriate use of this type of antibiotics. The purpose of this study was to investigate macrolide resistance in group A Streptococci strains isolated from clinical samples carrying mef gene and comparison of the phenotype and genotype of the mef gene carriers and prevalence of bacteria in the study population. Material and methods: Forty Beta-hemolytic streptococci pyogenes group A isolates obtained from 825

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... ious clinical specimens by using disk agar diffusion (DAD) were studied for the presence of mefA and mefE genes by polymerase chain reaction (PCR). Statistical analysis was performed by means of SPSS and Microsoft Office Excel softwares. Results: Prevalence of group A streptococcus was 4.84 % and also we found a macrolide resistance of 40% among isolates in the study population. By using D-test, the prevalence rates of phenotypes of GAS resistant to erythromycin among 8 isolates were 50% (4cases) for M-phenotyp,37.5% (3 cases) for cMLS-phenotype and 12.5% (1 case) for iMLSB-phenotype 1. Among 16 isolates resistant to macrolides, 8 (50%) had mefA, one (6.25%) had mefE and 7 isolates (43.75%), didn , t have mefA / E genes. Conclusion: In the present study M-phenotype had the highest frequency among GAS isolates resistant to erythromycin. Also, PCR can be used as a confirmatory routine test for interpretation of the results of anti-biogram and D-tests.