Group A beta-haemolytic streptococci (GAS) is one of the agents which are frequently isolated from upper respiratory tract infections. In addition to, it is determined that, different serogroups of streptococci cause upper respiratory tract infections, too. While GAS isolated from upper respiratory tract infections were susceptible to penicillin, resistance was observed to this antibiotic in the other serogroups.

In our study, 41 strains of beta-haemolytic streptococci were isolated from throat cultures of 132 children with upper respiratory tract infections. 78% of this strains were identified as group A, 15% as group B, 7% as group D and their susceptibility to penicillin, vancomycin, cefazolin, cefotaxime, eryhromycin, tetracycline, clindamycin, cloramphenicol and trimethoprim-sulfamethoxazole were investigated by disk diffusion method. While GAS and group B beta-hemolytic streptococci (GBS) were detected susceptible to penicillin, group d beta-haemolytic streptococci were all resistant to penicillin and cefazolin. The resistance to trimethoprim-sulfamethoxazole were found in 84% of GAS whereas, the resistance to this antibiotic and tetracycline were found in 33%, 100%, of GBS respectively.