[Multisite evaluation of a colorimetric broth microdilution antifungal susceptibility testing].
A new colorimetric microdilution antifungal susceptibility testing using an air-dried microplate containing serially diluted antifungal agents and an oxidation-reduction dye, sodium resazurin, as a color indicator to detect the growth of yeasts was evaluated at multiple sites. Six ATCC reference strains described in the National Committee for Clinical Laboratory Standards (NCCLS) M27-T, two quality control and four reference strains, were repeatedly tested against five antifungal agents, amphotericin B(AMPH), flucytosine (5-FC), fluconazole (FCZ), miconazole (MCZ) and itraconazole (ITZ) at 17 different laboratories. Of 1,521 MIC determinations, 1,393 (91.6%) were within the acceptable limits described in the M27-T, ranging from 23.8% to 100%. However, significant discrepancies from the M27-T limits were noted in some combinations, such as FCZ against C. albicans ATCC 90028. In addition, the MIC limits for MCZ and ITZ against the six reference strains were determined. A total of 1,645 clinical isolates of yeasts were tested against five antifungal agents. Most isolates of C. albicans were highly susceptible to the five agents with MIC90 ranging from 0.03 microgram/ml (MCZ) to 1.0 microgram/ml (AMPH). The MICs against AMPH and 5-FC were tightly clustered, except with C. krusei and Trichosporon spp. Whereas, the distribution of MICs for FCZ, MCZ and ITZ had a wide range from < or = 0.03 microgram/ml to > 64 micrograms/ml. From these results, it can be concluded that our colorimetric broth microdilution antifungal susceptibility test is reliable, easy-to-perform and a suitable alternative for the determination of the MICs in clinical microbiology laboratories.
Yamane
N
N
Department of Laboratory Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa.
Igari
J
J
D000666:Amphotericin B / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects* / Q000302:isolation & purification; D003124:Colorimetry; D004352:Drug Resistance, Microbial; D005069:Evaluation Studies as Topic; D015725:Fluconazole / Q000494:pharmacology; D005437:Flucytosine / Q000494:pharmacology; D007201:Indicator Dilution Techniques; D017964:Itraconazole / Q000494:pharmacology; D008825:Miconazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests / Q000379:methods*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000302:isolation & purification
D000935:Antifungal Agents; D017964:Itraconazole; D008825:Miconazole; D000666:Amphotericin B; D015725:Fluconazole; D005437:Flucytosine