Mupirocin is a pseudomonic acid, produced by Pseudomonas fluorescens,that is not related to any other antibiotic in clinical use. Available preparations are for external use only.


The various brands of mupirocin are mupiderm, bactrobam and supirocin.

Mode of action

Bacteriostatic—inhibits bacterial RNA and protein synthesis by binding to bacterial isoleucyl tRNA synthetase,preventing the incorporation of isoleucine into protein chains in the bacterial cell wall. It is active against staphylococci and certain other Gram-positive organisms.


Low-level resistance is due to spontaneous mutation resulting in altered access to binding sites in isoleucyl tRNA synthetase. High-level resistance is mediated on transferable plasmids by the mupA gene, which codes for a modified enzyme. Mupirocin resistance in MRSA has been associated with widespread use—prolonged use (greater than 7 days) is discouraged.

Clinical Use

Primarily used for skin infections, e.g. impetigo and folliculitis, and for nasal
decolonization of S.aureus or MRSA carriage. Mupirocin has also been used for treatment of secondarily infected eczema,burns,lacerations,and ulcers.


Given topically as a cream or nasal ointment.

Toxicity and side effects

Local reactions, such as pruritus, burning sensation, rash, and urticarial, may
occur, particularly if used on broken skin.


The price of mupirocin cream is around #2,000 to #2,500.

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Adapted from Oxford Handbook of Infectious Diseases and Microbiology.


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