
Methods: In a multicenter, prospective, placebo-controlled, double-blind study, we enrolled outpatient adults and children with uncomplicated skin abscesses less than or equal to 5 cm in diameter (less than or equal to 3 cm for ages 6 to 11 months and less than or equal to 4 cm for ages 1 to 8 years). Following abscess incision and drainage (I&D), subjects were randomized to clindamycin, trimethoprim-sulfamethoxazole (TMP-SMX), or placebo for ten days in a 1:1:1 ratio.
Results: We enrolled 786 subjects; 505 (64.2%) adults, 281 (35.8%) children, and 448 (57.0%) males. S. aureus was isolated from 527 subjects (67.0%) and MRSA was isolated from 388 (49.4%). At the 10-day, post-therapy, test of cure (TOC) visit, in the intention-to-treat population, mean cure rates among subjects receiving clindamycin (221/266, 83.1%) or TMP-SMX (215/263, 81.7%) were similar (p=0.73) and each was greater than placebo (177/257, 68.9%) (p=0.0001 and p=0.0008, respectively). Similar results were seen in the evaluable population. In clindamycin-treated subjects with a S. aureus lesion, seven of 13 subjects with a clindamycin-resistant isolate were cured (53.8%) compared with 145 of 170 subjects (85.3%) with a clindamycin-susceptible isolate. Adverse events were more frequent in the clindamycin group (58/265 21.9%) than the TMP-SMX (29/261, 11.1%) and placebo (32/255, 12.5%) groups; all resolved without sequelae. There was no Clostridium difficile-associated diarrhea. Among those initially cured, at the one-month follow-up visit, fewer new skin infections occurred among clindamycin recipients compared with those that received TMP-SMX or placebo.
Conclusion: Clindamycin or TMP-SMX, in conjunction with I&D, improves outcomes of subjects with a small abscess compared with I&D alone in both children and adults. The cure rates with either antibiotic exceeded placebo but were similar to each other. In subjects with a clindamycin-resistant S. aureus isolate, the cure rate was lower. Among subjects cured at the TOC visit, fewer new infections were noted at the one-month follow up visit.

R. S. Daum,
None
L. Immergluck, None
S. Fritz, None
C. B. Creech, None
D. Young, None
N. Kumar, None
M. Downing, None
S. Pettibone, None
R. Hoagland, None
S. J. Eells, None
C. Chiou, None
H. Chambers, None