Fusidic

Fusidic refers to a group of antibiotics derived from the fungus Fusidium coccineum. The most commonly used form is fusidic acid, a potent antibacterial agent effective against a range of Gram-positive bacteria, particularly Staphylococcus aureus. Fusidic acid works by inhibiting bacterial protein synthesis, specifically by interfering with the elongation factor G (EF-G). This mechanism disrupts the bacteria's ability to produce essential proteins, leading to cell death or inhibited growth.

Fusidic acid is primarily used topically in the form of creams, ointments, and eye drops to treat localized skin and eye infections. It is particularly useful for conditions like impetigo, folliculitis, and conjunctivitis caused by susceptible bacteria. Oral and intravenous formulations are also available for more severe or systemic infections, though their use is generally reserved due to potential side effects and the risk of resistance development.

Resistance to fusidic acid can develop, especially with prolonged or widespread use. This has led to recommendations for combining fusidic acid with other antibiotics in certain treatment regimens to minimize the emergence of resistant strains. The drug is generally well-tolerated, with local irritation being the most common side effect when used topically. Systemic side effects are less frequent but can include gastrointestinal disturbances and, rarely, liver function abnormalities.