title: Correlation between the E test and the CLSI M-38 A microdilution method to determine the activity of amphotericin B, voriconazole, and itraconazole against clinical isolates of Aspergillus fumigatus.
abstract: The in vitro activities of amphotericin B, itraconazole, and voriconazole against 283 clinical isolates of Aspergillus fumigatus were studied by comparing the E test method with the reference procedure NCCLS (CLSI) M-38A. The methods were considered to agree when the results of the MICs by E test were within +/-2 dilutions of the MICs obtained by CLSI M-38 A. Agreement of readings at 24, 48, and 72 h of incubation was as follows: amphotericin B: 4.2%, 98%, and 40.6%; itraconazole: 92.5%, 100%, and 89.9%; and voriconazole: 98.9%, 100%, and 99.7%. The correlation between methods to classify the strains as "susceptible" or "resistant" was very good for itraconazole and voriconazole after 48 h of incubation, but 23% of the strains were incorrectly classified by E test for amphotericin B. The E test is an efficacious method for antifungal susceptibility testing in A. fumigatus for itraconazole and voriconazole when the plates are read after 48 h of incubation. The use of the E test to study the activity of amphotericin B should be avoided.
authors.affiliation: Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañón, Universidad Complutense, Madrid, Spain. jguineaortega@yahoo.es
authors.forename: Jesús
authors.initials: J
authors.lastname: Guinea
authors.forename: Teresa
authors.initials: T
authors.lastname: Peláez
authors.forename: Luis
authors.initials: L
authors.lastname: Alcalá
authors.forename: Emilio
authors.initials: E
authors.lastname: Bouza
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D001232:Aspergillus fumigatus / Q000187:drug effects*; D006801:Humans; D017964:Itraconazole / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods; D011743:Pyrimidines / Q000494:pharmacology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014230:Triazoles / Q000494:pharmacology*; D065819:Voriconazole
chemical_list: D000935:Antifungal Agents; D011743:Pyrimidines; D014230:Triazoles; D017964:Itraconazole; D000666:Amphotericin B; D065819:Voriconazole