Fig 4.

Efficacy of topical antibiotics against CA-MRSA-infected wounds. Scalpel wounds on the backs of mice were inoculated with USA300 LAC::lux (2 × 10⁶ CFU/10 μl). Mice (n = 5 mice per group) were treated with topical mupirocin 2% ointment, retapamulin 1% ointment, or the corresponding vehicle ointment (polyethylene glycol [mupirocin] and white petrolatum [retapamulin]). Antibiotic treatment was initiated at 4 h after CA-MRSA inoculation and continued twice daily for the first 7 days. (A) Mean total lesion size (cm²) ± the SEM. (B) Bacterial counts as measured by in vivo bioluminescence imaging (mean total flux [photons/s] ± the SEM) (logarithmic scale). *, P < 0.05; †, P < 0.01; ‡, P < 0.001 (antibiotic treatment versus sham treatment [saline]) (Student's t test [two-tailed]).