Antifungal susceptibility of Cryptococcus neoformans isolates in HIV-infected patients to fluconazole, itraconazole and voriconazole in Spain:: 1994-1996 and 1997-2005

The antifungal drug susceptibility of 70 Cryptococcus neoformans isolates obtained in Spain from 1994 to 1996 (23 isolates) and from 1997 to 2005 (47 isolates) was investigated. The MICs of fluconazole, itraconazole and voriconazole were determined by the modified Clinical and Laboratory Standards Institute (CLSI; formerly National Committee for Clinical Laboratory Standards) broth microdilution method. The MIC50 and MIC90 for itraconazole and voriconazole did not change significantly from 1994 to 2005. The MIC50 of fluconazole remained stable and the MIC90 decreased by 2 log(2) dilution in the isolates collected from 1997 to 2005. We conclude that the in vitro resistance to fluconazole decreased over an 11-year period. In addition, a tendency for the development of possible cross-resistance between the three triazoles was observed. Copyright (C) 2007 S. Karger AG, Basel.