Increasing erythromycin resistance among group A streptococci causing tonsillitis in a tertiary care hospital in southern India.

Group A streptococci (GAS) (n = 1313) isolated from patients with clinical symptoms of pharyngitis or tonsillitis attending a tertiary care hospital in southern India during 1986-2002 were tested for susceptibility to penicillin and erythromycin. The overall erythromycin resistance rate was 2.7% (n = 36). During 1986-1993, erythromycin resistance was observed in only one (2%) isolate in 1987, but reappeared in 1994 (2.7%), increased to 5.8% in 1999, and reached a maximum frequency of 13.8% in 2002. All isolates were susceptible to penicillin. The data indicate the need for continued surveillance of susceptibility patterns among GAS isolates in order to monitor the development of antibiotic resistance.