Throat carriage rate and antimicrobial resistance trend of Streptococcus pyogenes among the asymptomatic Nepalese school children

Background: Streptococcus pyogenes or Group A streptococcus (GAS) causes several suppurative and non suppurative infections. Since the 1980s there has been re-emergence in the incidence of invasive S. pyogenes infections and rheumatic heart disease all over the world and hence throat carriage has assumed of great importance. Objectives: We carried out this preliminary study to determine the throat carriage rate and antimicrobial resistance trend of Streptococcus pyogenes or Group A streptococcus (GAS) among the Nepalese school children. Materials and methods: Four schools situated at different locations of Kathmandu valley were included in the study. Throat swabs from 350 students of age group 5-15 years were collected, immediately transported to the laboratory and were processed for S. pyogenes following standard microbiological procedures. Antimicrobial susceptibility testing of the isolates was performed by Kirby Bauer disc diffusion method following CLSI guidelines. Results: S. pyogenes was isolated from 10.9% (38/350) of the screened children. The GAS colonisation rate was statistically insignifi cant (P>0.05) with sex and age subgroups, although the rate was slightly higher among girls and age subgroup 9-12 years. No signifi cant difference in carrier rate was observed among different schools (P>0.05). Highest resistance rate was observed for Cotrimoxazole (71.05%) followed by Chloramphenicol (7.8%), Ciprofl oxacin (5.2%) and Erythromycin (5.2%). All isolates were susceptible to Azithromycin. No resistance was detected for penicillin and its derivative and Azithromycin. Conclusion: Antibiotic resistant GAS isolated from asymptomatic Nepalese children is a concern. When screened and appropriately treated with antibiotics, carriers can be prevented from spreading of streptococcal infections in the community. This would ultimately reduce the incidence of life-threatening sequelae which are debilitating and diffi cult to treat. It is recommended to conduct regular screening programs and GAS surveillance, and maintain rational use of antibiotics to keep GAS carriage/ infections and resistance in check.