The prevalence of pharyngeal carriers of Group A Beta-Hemolytic Streptococcus and antibiotic susceptibility pattern of this bacteria in Zahedan, southeast of Iran

Introduction: Group A Beta-Hemolytic Streptococcus (GABHS) is the most important and common bacterial cause of acute pharyngitis in children. Nowadays, cases of resistance to antibiotics have been reported due to unnecessary and extensive usage of antibiotics. The aim of this study was to determine the prevalence of healthy pharyngeal carriers and evaluate the antibiotic susceptibility of GABHS.
Materials and Methods: In this study among guidance school students of Zahedan aged 12 to 14 years, 1092 cases were selected randomly. After culturing the pharyngeal samples, GABHS was isolated and its susceptibility to different antibiotics was examined. Results were statistically analyzed by Chi-square and Exact fisher tests.
Result: 76 specimens of GABHS were isolated from 1092 cultivated specimens and the differences in the prevalence of GABHS between different age groups of two sexes and different age groups of each sex were not statistically significant. The antibiotic susceptibility ratios were 98.68% for cephalexin and cefazolin, 97.37% for erythromycin and 92.11% for penicillin and the difference was not statistically significant. The susceptibility to amoxicillin was 80.26%, which was significantly different from susceptibility to cephalexin and cefazolin (p<0.001), erythromycin (p=0.001) and penicillin (p=0.034).
Conclusion: In spite of widespread resistance to antibiotics, penicillin still is the first drug of choice for treatment of GABHS pharyngitis and erythromycin is the best alternative drug for patients sensitive to penicillin.