Epidemiology and molecular mechanisms of antifungal resistance in Candida and Aspergillus

The significant increase in the use of antifungal agents, both for the treatment of candidiasis and invasive aspergillosis and as azole fungicides in agricultural crop protection has resulted in the emergence of resistant clinical isolates, particularly to triazoles and echinocandins. Notably, among isolates that were primarily sensitive to fluconazole such as Candida parapsilosis and Candida tropicalis have witnessed an emerging resistance development. Also for echinocandins, the occurrence of Candida isolates with lower susceptibility to these drugs has been reported, which is possibly due to its broad clinical use. Triazole resistance among Aspergillus fumigatus and other Aspergillus species is commonly found in European and Asian countries. Specific mutations are associated with azole resistance in A. fumigatus and these mutations are now reported globally from six continents. Therefore, we highlight the need to conduct antifungal resistance surveillance studies using clinical isolates of Candida and Aspergillus in different geographical regions and monitoring of the infection rates in distinct population groups for early detection of resistance to these drugs and implementation of efficient policies for infection control and treatment.