Mupirocin (Bactroban, Centany) is a topical antibiotic produced by fermented Pseudomonas fluorescens. It has a narrow spectrum of activity, mostly against gram-positive aerobic bacteria (including Staphylococcus and methicillin-resistant Staphylococcus) and many strains of Streptococcus. It is also active against some gram-negative aerobic bacteria but is inactive against anaerobes, Chlamydia, and fungi. It has proved equal in efficacy in the treatment of impetigo when compared with oral erythromycin, with fewer adverse side effects.

   Mupirocin does not interfere with wound healing. It is active only on topical administration and is converted to an inert molecule on systemic administration. Prolonged use of mupirocin increases the risk of evolution of resistant organisms. Themechanism of action has not yet been fully classified, but it does differ from other available antiinfective agents, and there is little chance of cross-resistance developing. Also, unlike many other topical antibiotics, it rarely causes allergic sensitization.