Candida glabrata fungemia in transplant patients receiving voriconazole after fluconazole

Abstract

The clinical impact of voriconazole resistance in Candida glabrata is not well described. Five hematopoietic stem cell transplant recipients that developed breakthrough Candida glabrata bloodstream infections while receiving voriconazole are described and the clinical management and susceptibility profiles of their isolates are reported. All patients were markedly immunosuppressed, and in all cases, voriconazole use was preceded by prolonged fluconazole exposure (median 60 days); median voriconazole exposure prior to candidemia was 48 days. Isolates from 4 patients were shown to be resistant to fluconazole and itraconazole when tested in vitro; these same isolates had MICs to voriconazole and posaconazole > or = 2 microg/ml. Clinical failure to voriconazole may result from deficits in host defense, retained infected foci, and adaptation of the organism to environmental pressures, the specific sequence and mechanisms of which warrant further study. Clinicians must maintain a high index of suspicion for these infections in highly susceptible hosts despite voriconazole therapy, particularly when voriconazole use is preceded by prolonged fluconazole exposure.