Sensitivity of Penicillin in group A Beta-hemolytic Streptococus

Abstract

Background: Penicillin is a choice drug for treatment of streptococcal pharyngitis and is not toxic nor expensive. It is effective in all groups of streptococcus. Objective: To determine penicillin sensitivity in GABHS. Methods: 44 isolates of GABHS from 500 patients who referred to Qods hospital of Qazvin with symptoms of pharyngitis were collected to determine the frequency of antimicrobial resistance. Susceptibility testing was performed according to the guidelines of laboratory standards by the tube microdilution for penicillin. Antibiogram was performed by disk method for penicillin and 5 other antibiotics. Findings: Minimum bacterial concentration for GABHS was 0.0025 to 0.02. 100% of strains were sensitive to penicillin, amoxicilin and erythromycin but resistant to co-trimoxazole. Conclusion: Penicillin is the most effective and reliable drug for GABHS. Amoxicilin and erythromycin are recommended as choice drugs for cases of allergy.