Dermatologicals. ATC code:
D06AX09, Antibiotics and chemotherapeutics for dermatological use.
Pharmacology: Pharmacodynamics: Mode of action:
Mupirocin is an antibiotic produced through fermentation of Pseudomonas fluorescens
and inhibits bacterial protein synthesis by binding to bacterial isoleucyl t-RNA synthetase.
Mupirocin has bacteriostatic properties at minimum inhibitory concentrations and bactericidal properties at the higher concentrations reached when applied locally.
Mechanism of Resistance:
Low-level resistance in staphylococci is thought to result from point mutations within the usual staphylococcal chromosomal gene (ileS) for the target isoleucyl tRNA synthetase enzyme. High-level resistance in staphylococci has been shown to be due to a distinct, plasmid encoded isoleucyl tRNA synthetase enzyme.
Intrinsic resistance in Gram negative organisms such as the Enterobacteriaceae could be due to poor penetration of the outer membrane of the Gram-negative bacterial cell wall.
Due to its particular mode of action, and its unique chemical structure, mupirocin does not show any cross-resistance with other clinically available antibiotics.
The prevalence of acquired resistance may vary geographically and with time for selected species, and local information on resistance is desirable, particularly when treating severe infections. As necessary, expert advice should be sought when the local prevalence of resistance is such that the utility of the agent in at least some types of infection is questionable. (See table.)
Click on icon to see table/diagram/image
Systemic absorption of mupirocin through intact human skin is low although it may occur through broken/diseased skin. However, clinical trials have shown that when given systemically, it is metabolised to the microbiologically inactive metabolite monic acid and rapidly excreted.
Mupirocin is rapidly eliminated from the body by metabolism to its inactive metabolite monic acid which is rapidly excreted by the kidney.
Toxicology: Preclinical safety data:
Pre-clinical effects were seen only at exposures which give no cause for concern for man under normal conditions of clinical use. Mutagenicity studies revealed no risks to man.