Comparative analysis of Etest and broth microdilution method (AFST-EUCAST) for trends in antifungal drug susceptibility testing of Brazilian Cryptococcus neoformans isolates.
A prospective study was performed to evaluate the correlation between the proposed standard of the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antibiotic Susceptibility Testing (AFST-EUCAST) (document 7.1) and the commercial system Etest for determining the MICs of flucytosine, amphotericin B, fluconazole, itraconazole and voriconazole for a collection of 100 clinical and environmental isolates of Cryptococcus neoformans. The agreements among Etest MICs within +/-2 log2 dilutions of AFST-EUCAST standard MICs were greater for flucytosine, fluconazole and voriconazole (76, 78 and 88 %, respectively) than for amphotericin B (5 %), the lowest agreement, and itraconazole (67 %). Overall, the correlation coefficients were statistically significant (P<0.05), and it is suggested that the Etest and AFST-EUCAST method are reliable alternatives and present good correlation for all drugs evaluated except amphotericin B. However, the observed differences related to MICs for susceptible, susceptible dose dependent and resistant strains between the methods suggest that it will be necessary to carry out further studies, including assessment of interlaboratory agreement and correlation of MICs by different methods with in vivo response.
Dias
Amanda L T
ALT
Departamento de Ciências Biológicas, Laboratório de Microbiologia, Universidade Federal de Alfenas-MG, Alfenas-MG, Brazil.|Departamento de Microbiologia, Laboratório de Micologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo (USP), São Paulo-SP, Brazil.
Matsumoto
Flavia E
FE
Departamento de Microbiologia, Laboratório de Micologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo (USP), São Paulo-SP, Brazil.
Melhem
Marcia S C
MSC
Instituto Adolfo Lutz, São Paulo-SP, Brazil.
da Silva
Eriques G
EG
Departamento de Microbiologia, Laboratório de Micologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo (USP), São Paulo-SP, Brazil.
Auler
Marcos E
ME
Departamento de Microbiologia, Laboratório de Micologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo (USP), São Paulo-SP, Brazil.
de Siqueira
Antonio M
AM
Departamento de Ciências Biológicas, Laboratório de Microbiologia, Universidade Federal de Alfenas-MG, Alfenas-MG, Brazil.
Paula
Claudete R
CR
Departamento de Microbiologia, Laboratório de Micologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo (USP), São Paulo-SP, Brazil.
D000935:Antifungal Agents / Q000494:pharmacology; D001938:Brazil; D003453:Cryptococcosis / Q000382:microbiology*; D003455:Cryptococcus neoformans / Q000187:drug effects*; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods*; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity
D000935:Antifungal Agents; D011933:Reagent Kits, Diagnostic