Efficacy of oral beta-lactam versus non-beta-lactam treatment of uncomplicated cellulitis.

BACKGROUND

Preferred therapy for purulent skin and soft tissue infections is incision and drainage, but many infections cannot be drained. Empiric therapies for these infections are ill-defined in the era of community-acquired methicillin-resistant Staphylococcus aureus.

METHODS

A multicenter retrospective cohort study of outpatients treated for cellulitis was conducted to compare clinical failure rates of oral beta-lactam and non-beta-lactam treatments. Exclusion criteria included purulent infection requiring incision and drainage, complicated skin and soft tissue infection, chronic ulceration, and intravenous antibiotics. Failure rates were compared using logistic regression to adjust for both covariates associated with failure and a propensity score for beta-lactam treatment.

RESULTS

Of 2977 patients, 861 met inclusion criteria and were classified by treatment: beta-lactam (n = 631) or non-beta-lactam therapy (n = 230). Failure rates were 14.7% versus 17.0% (odds ratio [OR] 0.85, 95% confidence interval [CI], 0.56-1.31) for beta-lactam and non-beta-lactam therapy, respectively. Failure was associated with: age (P = .02), acute symptom severity (P = .03), animal bites (P = .03), Charlson score > 3 (P = .02), and histamine-2 receptor antagonist use (P = .09). Relative efficacy of beta-lactam therapy was greater after adjustment for factors associated with failure but remained statistically insignificant (adjusted OR 0.81, 95% CI, 0.53-1.24); adjusted including propensity score covariate (OR 0.71, 95% CI, 0.45-1.13). Discontinuation due to adverse effects differed between beta-lactam (0.5%) and non-beta-lactam (2.2%) therapies (P = .04).

CONCLUSION

There was no significant difference in clinical failure between beta-lactam and non-beta-lactam antibiotics for the treatment of uncomplicated cellulitis. Increased discontinuation due to adverse events with non-beta-lactam therapy was observed.