Trimethoprim-Sulfamethoxazole Therapy Reduces Failure and Recurrence in Methicillin-Resistant Staphylococcus aureus Skin Abscesses after Surgical Drainage Portions of the study were presented at meetings of the Pediatric Academic Societies, Boston, MA, April 28-May 1, 2012, and Washington, DC, May 4-7, 2013.

Objective To determine whether a 3-day vs 10-day course of antibiotics after surgical drainage of skin abscesses is associated with different failure and recurrence rates. Study design Patients age 3 months to 17 years seeking care at a pediatric emergency department with an uncomplicated skin abscess that required surgical drainage were randomized to receive 3 or 10 days of oral trimethoprim-sulfamethoxazole therapy. Patients were evaluated 10-14 days later to assess clinical outcome. Patients were followed for 6 months to determine the cumulative rate of recurrent skin infections. Results Among the 249 patients who were enrolled, 87% of wound cultures grew Staphylococcus aureus (S aureus) (55% methicillin-resistant S aureus [MRSA], 32% methicillin-sensitive S aureus), 11% other organisms, and 2% no growth. Thirteen patients experienced treatment failure. Among all patients, no significant difference in failure rates between the 3- and 10-day treatment groups was found. After we stratified patients by the infecting organism, only patients with MRSA infection were more likely to experience treatment failure in the 3-day group than the 10-day group (P =.03, rate difference 10.1%, 95% CI 2.1%-18.2%) Recurrent infection within 1 month of surgical drainage was more likely in patients infected with MRSA who received 3 days of antibiotics. (P =.046, rate difference 10.3%, 95% CI 0.8%-19.9%). Conclusion Patients with MRSA skin abscesses are more likely to experience treatment failure and recurrent skin infection if given 3 rather than 10 days of trimethoprim-sulfamethoxazole after surgical drainage. Trial registration ClinicalTrials.gov: NCT02024867.