Association between First Line Antibiotic Treatment of Abscesses and Persistence of Infection

Background: Skin and soft tissue infections (SSTIs) are often abscesses, treated with incision and drainage (I&D), followed by antibiotic course. A number of SSTI will fail to improve on this. Trimethoprim-sulfamethoxazole (TMP-SMX) or clindamycin are commonly prescribed antibiotics to treat abscesses. Little is known on cause for persistent SSTIs. We identified factors contributing to persistent infections among children seeking re-evaluation of a previously treated SSTI. We hypothesized that TMP-SMX as a primary antibiotic for treatment of abscesses leads to significant rates of persistent infections, particularly those located below the waist.

Methods: Retrospective analysis of a large prospective pediatric SSTI study conducted in 3 pediatric EDs. We analyzed data on patients who were re-evaluated for previously treated SSTI. Persistent infection is defined as SSTI presenting >48 hours after previous treatment. Patients were excluded if they had immune deficiency, multiple abscesses, or presented >14 days after initial treatment. Demographic information, past medical history, and details of SSTI were obtained. Details of (1) time between start of prior antimicrobial therapy and SSTI re-evaluation; (2) antibiotics prescribed; (3) body location of SSTI; and (5) I&D culture results. Bivariate and multiple logistic regression analyses were conducted based on covariates of interest determined a priori.

Results: From June 2013 to January 2015, 378 of 1,013 SSTI were re-evaluated for persistent infection. The average age was 6.59 years. 48.41% (183/378) were White, and 31.22% (118/378) Black. 57.67% (218/378) were female. 31.22% (118/378) were on TMP-SMX therapy at time of re-evaluation, 21.96% (83/378) on Clindamycin, and 16.67% (63/378) on multiple antibiotics. Patients with abscesses located below the waist (60.85%, 230/378) were more likely to be < 5 years (OR 3.60, 95% CI: 2.13-6.10, p value < 0.0001) and on TMP-SMX (OR 3.75, 95% CI: 1.94-7.22, p value < 0.0001) at initial treatment, compared to patients on other antibiotics.

Conclusion: Majority of SSTI children were re-evaluated while on TMP-SMX or clindamycin. Patients needing SSTI re-evaluation were more likely to be onTMP-SMP, have SSTI located below the waist, and < 5 years of age.