Comparative Activity In Vitro of Ravuconazole (RVZ) against Fluconazole-Susceptible (FLZ-S) and Fluconazole-Resistant (FLZ-R) Clinical Isolates of Candida spp.


Author address: 

Inst. de Salud Carlos III, Majadahonda, Spain


Background: Ravuconazole (Bristol-Myers Squibb, BMS-207147) is a new broad-spectrum triazole agent. In vitro and animal studies demonstrate that is very active against yeasts and molds. We have analyzed the activity in vitro of RVZ against a collection of FLZ-S and FLZ-R clinical isolates of Candida spp. Methods: A total of 70 FLZ-R (FLZ MIC>16 µg/ml, resistant and S-DD categories of the NCCLS) and 120 FLZ-S clinical isolates were included. Candida krusei ATCC6258 and Candida parapsilosis ATCC22019 were included as QC strains. Yeasts were tested using the proposed standard for Antifungal Susceptibility Testing of Yeasts of the European Committee on Antibiotic Susceptibility Testing (AFST-EUCAST), a method based on reference procedure of NCCLS M27-A, but incorporating modifications (RPMI-2% glucose, inoculum size of 105 CFU/ml, spectrophotometrical reading) in order to get an automated AFST and to shorten from 48h to 24h the incubation period for MIC determination. Results: Geometric means of MICs (µg/ml) of RVZ per species tested were as follows: C. albicans: FLZ-S (n=25): 0.007, FLZ-R (n=25): 0.34; C. parapsilosis: FLZ-S (n=25): 0.007, FLZ-R (n=2): 0.01; C. tropicalis: FLZ-S (n=25): 0.02, FLZ-R (n=13): 0.61; C. glabrata: FLZ-S (n=25): 0.11, FLZ-R (n=25): 0.33; C. guilliermondii: FLZ-S (n=12): 0.10, FLZ-R (n=3): 0.12; C. lusitaniae: FLZ-S (n=8): 0.12, FLZ-R (n=2): 0.12. Conclusions: RVZ exhibited a potent activity in vitro against FLZ-R isolates of Candida spp. However, for FLZ-R isolates, the MICs of RVZ were proportionally higher than for FLZ-S strains.

abstract No: 


Full conference title: 

42nd Interscience Conference on Antimicrobial Agents and Chemotherapy
    • ICAAC 42nd