In vitro susceptibility of Chilean Cryptococcus neoformans strains of clinical source

Abstract

Cryptococcus yeast infections primarily affect immunocompromised patients. There have been few susceptibility studies conducted for this genus in Chile. To determine the in vitro susceptibility to commonly used antifungals and evaluate the concordance between susceptibility determined by microdilution in broth and commercially available strips. Descriptive study of 21 Cryptococcus strains, isolated from cerebrospinal fluid and blood. The MIC50 and MIC90 for fluconazole, voriconazole and amphotericin B was determined by broth microdilution (Sensititre Yeast One®) and by commercial drug sensitivity strips (MIC Test Strips). All strains corresponded to C. neoformans. The ranges of MIC50 and MIC90 for each antifungal studied were wide by both methods. The essential agreement between Sensititre Yeast One test and strips was 24, 62 and 29% for fluconazole, voriconazole and amphotericin B, respectively. The Sensititre Yeast One test and MIC Test Strips exhibited poor essential concordance, especially for fluconazole and amphotericin B.