Antifungal Drugs: Mechanism of Action and Resistance

Overuse of antifungal drugs in recent years has developed resistance against these drugs. The significant clinical influence of resistance has resulted in increased interest in the study of antimicrobial resistance from all possible angles. The mechanisms of resistance, better methods of resistance detection, alternative methods to treat the infections of resistant organisms, and all the possible strategies to control and prevent the occurrence of resistance should be addressed. In this chapter, common drugs used against fungi, their mode of action, and mechanism of resistance are discussed. Allylamines and azole inhibit the ergosterol synthesis, echinocandin binds with glucan synthase to inhibit the synthesis of the cell wall, 5-fluorocytosine (5-FC) inhibits the synthesis of macromolecules, and polyenes physiochemically interact with sterols in the plasma membrane. While the alteration in the biosynthesis of sterols, overexpression, reduction, and alteration in concentration or structure of target enzymes could contribute to the development of resistance against the antifungal drugs. All the ongoing efforts to identify the resistance and its emergence is used for a safe future.