Trimethoprim-sulfamethoxazole therapy for children with acute osteomyelitis

The emergence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has complicated the conventional management of osteomyelitis. While oral clindamycin is commonly used to treat acute CA-MRSA osteomyelitis, the emergence of inducible clindamycin resistance among CA-MRSA isolates has made alternative therapy necessary. The excellent oral bioavailability, susceptibility profile, favorable palatability, and low cost of trimethoprim-sulfamethoxazole (TMP-SMX) make this drug an attractive option for treating osteomyelitis, yet its clinical efficacy for osteomyelitis has not been established.

Between October 1998 and September 2009, 20 children who received a TMP-SMX-containing regimen for acute osteomyelitis at All Children's Hospital were identified from hospital records, and their cases reviewed for clinical outcome and drug safety.

Patients ranged in age from 9 months to 17 years. Twelve (60%) of the patients were male. Causative pathogens were found in 8 (40%) cases of which 5 were CA-MRSA and 3 were methicillin-susceptible Staphylococcus aureus. Eleven patients (55%) received TMP-SMX as their primary therapy. The median dose of TMP-SMX was 16.4 mg/kg/d. During TMP-SMX therapy, 8 patients (40%) experienced adverse events; all were considered mild. Duration of total therapy was 26 to 59 days, with a median of 40 days. All 20 patients were considered cured of their infection at the end of therapy.

Orally administered TMP-SMX appears to be a useful and well-tolerated therapy for treatment of acute osteomyelitis in children. Further prospective comparative studies will be needed to confirm this observation.