Purpose of review: The global emergence of antifungal resistance among Candida spp. and Aspergillus spp. is a growing threat to public health, driven largely by the expanding use of antifungals in both the clinical and agricultural settings. As treatment options remain limited, understanding mechanisms and risk factors for antifungal resistance is essential to retaining their clinical utility.
Recent findings: Invasive candidiasis is increasingly caused by non-albicans Candida species with reduced susceptibility to first-line antifungals, making empiric treatment decisions difficult. Echinocandin resistance in C. glabrata is increasing at some high-risk centers, and multi-drug-resistant isolates are increasingly encountered. Of large concern is the rapid and global emergence of C. auris, a species associated with a high propensity for developing multi-drug resistance and nosocomial transmission. Azole resistance is now becoming more common in Aspergillus isolates as well, with breakthrough infections occurring in patients previously managed with azoles antifungals. The appearance of azole-resistant Aspergillus isolates in azole-naïve patients is also concerning, given it is now accepted that this may be due to the use of non-human azole compounds in pesticides. Due to the climbing use of antifungals in both the clinical and agricultural sectors, the frequency of encounters with antifungal-resistant isolates will undoubtedly rise in parallel. Antifungal stewardship will need to become a new priority for antimicrobial stewardship programs in order to preserve our current selection of antifungal agents. Rapid diagnostics may help stewardship efforts by decreasing the time it takes to determine if an antifungal agent is indicated for a patient.
Keywords: Antifungal resistance; Antifungal susceptibility; Aspergillus; Azole; Candida; Echinocandin.