Natamycin (pimaricin) is an antifungal macrolide polyene that binds to cell membrane sterols. Natamycin (pimaricin) is an antifungal macrolide polyene that binds to cell membrane sterols. Target: Antifungal Natamycin (INN), also known as pimaricin and sometimes sold as Natacyn, is a naturally occurring antifungal agent produced during fermentation by the bacterium Streptomyces natalensis, commonly found in soil. Natamycin has a very low solubility in water; however, natamycin is effective at very low levels. There is an MIC (minimum inhibitory concentration) of less than 10 ppm for most molds. Natamycin is classified as a macrolide polyene antifungal and, as a drug, is used to treat fungal keratitis. It is especially effective against Aspergillus and Fusarium corneal infections. Other common members of the polyene macrolide antifungal family are amphotericin B, nystatin, and filipin. Natamycin is also used in the food industry as a natural preservative. Natamycin is used to treat fungal infections, including Candida, Aspergillus, Cephalosporium, Fusarium and Penicillium. It is applied as a cream, in eyedrops, or (for oral infections) in a lozenge. Natamycin shows negligible absorption into the body when administered in these ways. When taken orally, little or none is absorbed from the gastrointestinal tract, making it inappropriate for systemic infections.