<Li> Hypersensitivity reactions, including Stevens - Johnson syndrome in some cases </Li> <Li> Rash, itching, burning and acute generalized exanthematous pustulosis </Li> <P> Like amphotericin B and natamycin, nystatin binds to ergosterol, a major component of the fungal cell membrane . When present in sufficient concentrations, it forms pores in the membrane that lead to K leakage, acidification, and death of the fungus . Ergosterol is a sterol unique to fungi, so the drug does not have such catastrophic effects on animals or plants . However, many of the systemic / toxic effects of nystatin in humans are attributable to its binding to mammalian sterols, namely cholesterol . This is the effect that accounts for the nephrotoxicity observed when high serum levels of nystatin are achieved . </P> <P> Nystatin A (or referred to as nystatin) is biosynthesized by a bacterial strain, Streptomyces noursei . The structure of this active compound is characterized as a polyene macrolide with a deoxysugar D - mycosamine, an aminoglycoside . The genomic sequence of nystatin reveals the presence of the polyketide loading module (nysA), six polyketide synthases modules (nysB, nysC, nysI, nysJ, and nysK) and two thioesterase modules (nysK and nysE). It is evident that the biosynthesis of the macrolide functionality follows the polyketide synthase I pathway . </P>

What is the mechanism of action of nystatin
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