Understanding antibiotic choices for skin and soft tissue infections

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) causes most purulent skin and soft tissue infections (SSTIs) in children, which has resulted in a trend toward empiric use of antibiotics with activity against MRSA. To determine any difference in clinical outcome related to type of antibiotic, investigators compared outcomes in children with SSTIs who were treated with either cephalexin (a traditional antistaphylococcal antibiotic without activity against MRSA) and those treated with clindamycin (an antibiotic with high clinical activity against CA-MRSA).

The 200 children in the study (age range, 6 months to 18 years) presented to a pediatric outpatient center with an uncomplicated, purulent SSTI; in 69% of patients, MRSA was cultured from wounds. Almost all the children had spontaneous drainage or a drainage procedure before being treated with antibiotics. The children were equally randomized to receive cephalexin (40 mg/kg per day taken orally in divided doses administered 3 times a day) or clindamycin (20 mg/kg per day taken orally in divided doses administered 3 times a day).

When patients returned to the center for reevaluation 48 to 72 hours after the initial visit, infection had improved or resolved in 94% of the cephalexin group and 97% of the clindamycin group. By 7 days, all children showed improvement, with complete resolution in 97% of those in the cephalexin group and 94% of the clindamycin group.

Commentary

So, does this mean that choice of antibiotic doesn't matter, or that use of any antibiotic is unnecessary in most children with SSTIs after adequate incision and drainage and wound care? Although this study did not include a placebo arm, the cephalexin arm might be considered a placebo for the portion of patients with MRSA infection. And the researchers cite 1 study in which no difference in treatment failure was found in SSTIs treated with cotrimoxazole or placebo. It would be nice to avoid use of foul-tasting liquid clindamycin. It would be nicer still to treat these infections with local care alone. Perhaps that is the approach we'll arrive at in afebrile children older than 1 year with SSTIs. -Michael Burke, MD