Resistance to antifungal agents in the critical care setting: problems and perspectives.

As is the case with antibacterial agents, the increasing use of antifungal agents has led to development of antifungal resistance, the most clinically important of which is the resistance of Candida to fluconazole. While mutation to high-level fluconazole resistance is possible, the most important aspect of fluconazole resistance for patients in the ICU is the possibility of an epidemiologic shift away from such susceptible species as C. albicans and C. parapsilosis toward the most resistant species, such as C. glabrata and C. krusei. Resistance to amphotericin B by Candida is also possible, but less frequent. Strategies for treating invasive Candida infections must consider the relative rates of non-C. albicans Candida infection and the likelihood of antifungal resistance. The agents that cause invasive mold infections in the ICU are intrinsically moderately resistant to the available antifungal agents, and therapy depends less on the choice of antifungal therapy than on the correction of predisposing factors. The role of susceptibility testing as a guide in selecting appropriate therapy for all of these infections is as yet incompletely defined, but testing for resistance to fluconazole may soon be ready for clinical use.