Mupirocin (pseudomonic acid A, or Bactroban or Centany) is an antibiotic originally isolated from Pseudomonas fluorescens. It is used topically, and is primarily effective against Gram-positive bacteria. Mupirocin is bacteriostatic at low concentrations and bactericidal at high concentrations. Mupirocin has a unique mechanism of action, which is selective binding to bacterial isoleucyl-tRNA synthetase, which halts the incorporation of isoleucine into bacterial proteins. Because this mechanism of action is not shared with any other antibiotic, mupirocin has few problems of antibiotic cross-resistance.
Indication
For the treatment of Staphylococci nasal carriers.
Pharmacology
Mupirocin, an antibiotic produced from Pseudomonas fluorescens, is structurally unrelated to any other topical or systemic antibiotics. Mupirocin is used to treat infection caused by Staphylococcus aureus and beta-hemolytic streptococci including Streptococcus pyogenes. This antibiotic has little, if any, potential for cross-resistance with other antibiotics.
Affected Organisms
Enteric bacteria and other eubacteria
Biotransformation
Hepatic. Following intravenous or oral administration, mupirocin is rapidly metabolized. The principal metabolite is monic acid, which has no antibacterial activity.
Absorption
No measurable systemic absorption
Half Life
20 to 40 minutes
Protein Binding
97%
Elimination
Following the application of Centany (mupirocin ointment),2% to a 400 cm2 area on the back of 23 healthy volunteers once daily for 7 days, the mean (range) cumulative urinary excretion of monic acid over 24 hrs following the last administration was 1.25% (0.2% to 3.0%) of the administered dose of mupirocin.