Context. Animal model studies have demonstrated the failure of penicillin to cure Streptococcus pyogenes myositis and have suggested that clindamycin is a more effective treatment.
Objective. To determine the most effective antibiotic treatment for invasive S. pyogenes infection in humans.
Design and setting. We conducted a retrospective review of the outcomes of all inpatients from 1983 to 1997 treated for invasive S. pyogenes infection at Children's Hospital.
Patients. Fifty-six children were included, 37 with initially superficial disease and 19 with deep or multiple tissue infections.
Main outcome measure. Lack of progression of disease (or improvement) after at least 24 h of treatment.
Results. The median number of antibiotic exposures was 3 per patient (range 1 to 6) with clindamycin predominating in 39 of 45 courses of protein synthesis-inhibiting antibiotics and beta-lactams predominating amongst the cell wall-inhibiting antibiotics in 123 of 126 of the remainder. Clindamycin was often used in combination with a beta-lactam antibiotic. Overall there was a 68% failure rate of cell wall-inhibiting antibiotics when used alone. Patients with deep infection were more likely to have a favorable outcome if initial treatment included a protein synthesis-inhibiting antibiotic as compared with exclusive treatment with cell wall-inhibiting antibiotics (83% vs. 14%, P = 0.006) with a similar trend in those with superficial disease (83% vs. 48%, P = 0.07). For those children initially treated with cell wall-inhibiting antibiotics alone, surgical drainage or debridement increased the probability of favorable outcome in patients with superficial disease (100% vs. 41%, P = 0.04) with a similar trend in a smaller number of deep infections (100% vs. 0%, P = 0.14).
Conclusions. This retrospective study suggests that clindamycin in combination with a beta-lactam antibiotic (with surgery if indicated) might be the most effective treatment for invasive S. pyogenes infection.