Comparison of antibiotic treatments for cellulitis

Among patients with uncomplicated cellulitis, the use of an antibiotic regimen with activity against MRSA did not result in higher rates of clinical resolution compared to an antibiotic lacking MRSA activity; however, certain findings suggest further research may be needed to confirm these results, according to a study published by JAMA.

Emergency department visits for skin infections in the United States have increased with the emergence of methicillin-resistant Staphylococcus aureus (MRSA). To determine whether addition of a MRSA-active antimicrobial improves outcomes in patients with cellulitis, Gregory J. Moran, M.D., of Olive View-UCLA Medical Center, Los Angeles, and colleagues randomly assigned emergency department patients presenting with cellulitis without a wound or abscess to receive a regimen with activity against MRSA, the antibiotics cephalexin plus trimethoprim-sulfamethoxazole (n = 248), or a regimen lacking MRSA activity, cephalexin plus placebo (n = 248) for 7 days.

Among the participants, 496 were included in the modified intention-to-treat analysis and 411 in the per-protocol analysis. In the per-protocol population, clinical cure occurred in 83.5 percent of participants in the cephalexin plus trimethoprim-sulfamethoxazole group vs 85.5 percent in the cephalexin group. In the modified intention-to-treat population, clinical cure occurred in 76.2 percent of participants in the cephalexin plus trimethoprim-sulfamethoxazole group vs 69 percent in the cephalexin group.

The authors write that because the results from the modified intention-to-treat analysis did not exclude the possibility of clinical superiority of cephalexin plus trimethoprim-sulfamethoxazole, more research may be necessary to more definitively answer this question.

Several limitations of the study are noted in the article, including that even with 500 participants, the power of this trial is limited such that the possibility that regimens with activity against MRSA could improve outcomes in some subgroups cannot be excluded.