Comparison of two probes for testing susceptibilities of pathogenic yeasts to voriconazole, itraconazole, and caspofungin by flow cytometry.
A cytometric approach to determine the susceptibilities of Candida spp. and Cryptococcus neoformans to voriconazole, itraconazole, and caspofungin is described. A total of 63 clinical isolates with different susceptibility patterns were exposed for 1, 2, 4, and 6 h to serial concentrations of each antifungal agent, followed by staining with two fluorescent probes: propidium iodide (PI) and FUN-1. FUN-1 was able to identify the susceptibility patterns of the assayed strains to the three agents after 1 h. PI penetrated a maximum of 50% of the cells treated with PI, at the highest concentration of caspofungin, 16 mug/ml, after 6 h of incubation (this percentage varied with the strain and was drug concentration and time of incubation dependent) and did not stain cells treated with high concentrations of either azole after 6 h. The use of FUN-1 appears to be an excellent fast and reliable alternative to the classical dilution method for determining the susceptibility of Candida spp. and C. neoformans to these three antifungal agents.
Pina-Vaz
Cidália
C
Department of Microbiology, Porto School of Medicine, Alameda Prof. Hernani Monteiro, Porto, Portugal. cpinavaz@yahoo.com
Costa-de-Oliveira
Sofia
S
Rodrigues
Acácio G
AG
Espinel-Ingroff
Ana
A
D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects; D000077336:Caspofungin; D003455:Cryptococcus neoformans / Q000187:drug effects; D054714:Echinocandins; D005434:Flow Cytometry / Q000379:methods*; D005456:Fluorescent Dyes; D006801:Humans; D017964:Itraconazole / Q000494:pharmacology; D055666:Lipopeptides; D008826:Microbial Sensitivity Tests / Q000379:methods; D010456:Peptides, Cyclic / Q000494:pharmacology; D011419:Propidium; D011743:Pyrimidines / Q000494:pharmacology; D014230:Triazoles / Q000494:pharmacology; D065819:Voriconazole
D000935:Antifungal Agents; D054714:Echinocandins; D005456:Fluorescent Dyes; D055666:Lipopeptides; D010456:Peptides, Cyclic; D011743:Pyrimidines; D014230:Triazoles; D017964:Itraconazole; D011419:Propidium; D000077336:Caspofungin; D065819:Voriconazole