Mupirocin is an antibiotic of the monoxycarbolic acid class.

Mupirocin is bacteriostatic at low concentrations and bactericidal at high concentrations. It is used topically and is effective againstGram-positive bacteria, including MRSA.

Mupirocin is a mixture of several pseudomonic acids, with pseudomonic acid A (PA-A) constituting greater than 90% of the mixture. Also present in mupirocin are pseudomonic acid B with an additional hydroxyl group at C8,pseudomonic acid C with a double bond between C10 and C11, instead of the epoxide of PA-A, and pseudomonic acid D with a double bond at C4` and C5` in the 9-hydroxy-nonanoic acid portion of mupirocin.

The product of a variety of Gram-positive bacteria associated with skin infections especially staphylococcus and streptococcus highly sensitive to resistant Staphylococcus aureus is also effective. Certain Gram-negative bacteria have some antibacterial effect.With no cross-resistance to other antibiotics.

Infections of skin and soft tissue caused by Gram-positive cocci, such as impetigo, boils, folliculitis primary infection and eczema, dermatitis, ulcers, and other skin trauma secondary infection.

Mupirocin is used as a topical treatment for bacterial skin infections, for example, furuncle, impetigo, open wounds, which are typically due to infection by Staphylococcus aureus or Streptococcus pyogenes. It is also useful in the treatment of superficial methicillin-resistant Staphylococcus aureus (MRSA) infections.Mupirocin is inactive for most anaerobic bacteria, mycobacteria, mycoplasma, chlamydia, yeast and fungi.
Intranasal mupirocin before surgery is effective for prevention of post-operative wound infection with Staphylcoccus aureus and preventative intranasal or catheter-site treatment is effective for reducing the risk of catheter site infection in persons treated with chronic peritoneal dialysis.