Trend of antibiotic susceptibility of Streptococcus pyogenes isolated from respiratory tract infections in tertiary care hospital in south Karnataka

Streptococcus pyogenes is recognized as an important pathogen of respiratory tract infections. The rapidly, emerging problem of antibiotic resistant Streptococcus pyogenes is a major issue nowadays. The present study aimed to evaluate the antibiotic susceptibility of Streptococcus pyogenes isolated from upper respiratory tract infections in tertiary care hospital of south Karnataka. A retrospective study was conducted over a period of two years. The specimens were processed by Gram staining and aerobic culture. The bacteria were isolated as per standard protocols. The minimum inhibitory values and extent of antibiotic resistance of commonly used antimicrobials were analysed for the isolated strains. A total of 2123 specimens were received from patients with respiratory tract infections, among which, 50 Streptococcus pyogenes isolates were obtained. Out of these, 8% were not sensitive to penicillin. Using VITEK 2 system, the prevalence of resistances to cefotaxime, erythromycin, tetracycline, levofloxacin, clindamycin and ceftriaxone were 4.2%, 83%, 51%, 8.9%, 40% and 5.3% respectively. It is important to know about the prevalence of resistance and rising MIC values of commonly used antibiotics regarding Streptococcus pyogenes to avoid therapeutic failures.