Role of antifungal susceptibility testing in patient management.
OBJECTIVE
The review focuses on the evolving role of antifungal susceptibility testing in the clinical management of patients with invasive fungal infections. It will clarify how to clinically interpret available susceptibility testing methods.


RESULTS
Fluconazole susceptibility testing for yeasts has now shown a relationship between fluconazole resistance and therapeutic failure. Of increasing concern are the reported cases of fluconazole cross-resistance to the newer triazoles. The correlation between amphotericin B and echinocandin susceptibility testing for yeasts, resistance, and outcomes is unknown. Although there are reports of clinical failures with echinocandins, resistance is uncommon and susceptibility testing is unhelpful. There are standardized methods of testing for the triazoles and amphotericin B against molds; however, resistance has not been correlated with outcomes due to host and laboratory factors. Knowing the intrinsic resistance of molds to particular antifungals is of greater importance. Posaconazole is a potent new antifungal agent against many difficult-to-treat molds including fusariosis and zygomycosis.


CONCLUSIONS
Antifungal susceptibility testing of yeasts can assist in treating patients with prior antifungal exposure in determining resistance or cross-resistance. Mold susceptibility testing is of limited clinical benefit, while posconazole is an exciting new agent for treating difficult invasive fungal infections.
Forrest
Graeme
G
Division of Infectious Diseases, University of Maryland, Baltimore, Maryland 21201, USA. gforrest@medicine.umaryland.edu
D000935:Antifungal Agents / Q000627:therapeutic use*; D025141:Drug Resistance, Fungal; D005658:Fungi / Q000187:drug effects*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009181:Mycoses / Q000188:drug therapy* / Q000382:microbiology*
D000935:Antifungal Agents