Bactericidal efficacy of mupirocin in multi-antibiotic resistant Staphylococcus aureus burn wound infection.

Abstract

Methicillin resistant Staphylococcus aureus strains (MRSA) have become increasingly prevalent as pathogenic organisms, especially in burn wounds, with an associated mortality of 20-40% among those clinically infected. Mupirocin ointment, a new topical antibiotic, has proved in vitro and in vivo to be highly effective in the treatment of MRSA infections. A modified Walker burn wound model was used to define the rate of trans-eschar penetration, biodynamic availability and bactericidal efficacy of 2% mupirocin ointment in established MRSA burn wound infection. In-vitro penetration trials confirmed the effective diffusion of mupirocin through 1.5 mm eschar within 2 h. A single topical application of mupirocin resulted in a 98.3% (5.67 x 10(8) cfu/g of tissue--1.0 x 10(7) cfu/g of tissue) reduction in intra-eschar viable organisms within 36 h post application. A second topical application of mupirocin at 24 h resulted in a total reduction of 99.6% in viable intra-eschar organisms (1.85 x 10(8) cfu/gram of tissue--6.76 x 10(5) cfu/g of tissue). It is concluded that mupirocin is highly effective in controlling MRSA burn wound infection and should be applied topically every 24 h.