Improved outcome of clindamycin compared with beta-lactam antibiotic treatment for invasive Streptococcus pyogenes infection

Context. Animal model studies have demonstrated the failure of penicillin t o cure Streptococcus pyogenes myositis and have suggested that clindamycin is a more effective treatment. Objective. To determine the most effective antibiotic treatment for invasiv e 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 d isease 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 synt hesis-inhibiting antibiotics and betalactams predominating amongst the cell wall-inhibiting antibiotics in 123 of 126 of the remainder. Clindamycin wa s often used in combination with a beta lactam antibiotic. Overall there wa s a 68% failure rate of cell wall-inhibiting antibiotics when used alone. P atients with deep infection were more likely to have a favorable outcome if initial treatment included a protein synthesis-inhibiting antibiotic as co mpared with exclusive treatment with cell wall-inhibiting antibiotics (83% us. 14%, P = 0.008) with a similar trend in those with superficial disease (83% vs. 48%, P = 0.07). For those children initially treated with cell wal l-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 in fections (100% us. 0%, P = 0.14). Conclusions. This retrospective study suggests that clindamycin in combinat ion with a beta-lactam-antibiotic (with surgery if indicated) might be the most effective treatment for invasive S. pyogenes infection.