Retapamulin is a novel pleuromutilin antibacterial and the first new topical antibacterial in nearly 20 years. 14 Pleuromutilins, derived from the fungus Clitopilus passeckerianus , have antibacterial activity against gram-positive bacterial organisms. 20 Retapamulin acts on three key aspects of bacterial protein synthesis, making it far less likely to induce resistant strains. In 2007, the . Food and Drug Administration approved retapamulin 1% ointment for the treatment of impetigo due to S. aureus (methicillin-susceptible isolates only) or S. pyogenes in adults and children at least nine months of age. Retapamulin is not approved for intranasal staphylococcal carrier treatment or treatment of MRSA-related skin infections. 6 , 19 Pricing of the two topical treatment options available in the United States varies depending on preparation. Mupirocin is available as a less expensive generic version and as a brand. All available mupirocin products are less expensive than the newer brand-only retapamulin ointment ( Table 2 6 , 8 , 11 , 14 , 17 – 19 ) .