Antifungal Drug Resistance: Clinical Importance, in vitro Detection and Implications for Prophylaxis and Treatment

Abstract

<i>Candida</i> species and <i>Aspergillus</i> species are the primary opportunistic fungal pathogens in immunocompromised patients and are associated with high morbidity and mortality. The epidemiology of invasive fungal infections is changing, challenging the therapeutic options. To date, 4 classes of antifungal drugs have been predominantly used to treat and prevent invasive fungal disease: azoles, echinocandins, flucytosine and polyenes. Large-scale surveys of in vitro antifungal drug resistance among clinical fungal pathogens have shown that emerging resistance among naturally-susceptible species is not a widespread problem; however, ongoing surveillance to detect trends in the number of infections caused by species that are intrinsically less susceptible is warranted. Antifungal prophylaxis has been shown to be effective in reducing the incidence in certain patient groups, including hematopoietic stem cell transplant recipients. Continued efforts to define specific risk factors for invasive fungal infections, implement effective prevention strategies, develop new antifungal agents, and improve the clinical utility of in vitro antifungal susceptibility testing will better position us to reduce the clinical impact of antifungal drug resistance.