Comparative Evaluation of FUNGITEST and Broth Microdilution Methods for Antifungal Drug Susceptibility Testing of Candida Species and Cryptococcus neoformans

Abstract

The FUNGITEST method (Sanofi Diagnostics Pasteur, Paris, France) is a microplate-based procedure for the breakpoint testing of six antifungal agents (amphotericin B, flucytosine, fluconazole, itraconazole, ketoconazole, and miconazole). We compared the FUNGITEST method with a broth microdilution test, performed according to National Committee for Clinical Laboratory Standards document M27-A guidelines, for determining the in vitro susceptibilities of 180 isolates ofCandida spp. (50 C. albicans, 50C. glabrata, 10 C. kefyr, 20C. krusei, 10 C. lusitaniae, 20C. parapsilosis, and 20 C. tropicalisisolates) and 20 isolates of Cryptococcus neoformans. Overall, there was 100% agreement between the methods for amphotericin B, 95% agreement for flucytosine, 84% agreement for miconazole, 83% agreement for itraconazole, 77% agreement for ketoconazole, and 76% agreement for fluconazole. The overall agreement between the methods exceeded 80% for all species tested with the exception ofC. glabrata (71% agreement). The poorest agreement between the results for individual agents was seen with C. glabrata (38% for fluconazole, 44% for ketoconazole, and 56% for itraconazole) and C. tropicalis (50% for miconazole). The FUNGITEST method misclassified as susceptible 2 of 12 (16.6%) fluconazole-resistant isolates, 2 of 10 (20%) itraconazole-resistant isolates, and 4 of 8 (50%) ketoconazole-resistant isolates of several Candida spp. Further development of the FUNGITEST procedure will be required before it can be recommended as an alternative method for the susceptibility testing of Candida spp. or C. neoformans.

Correlation between the procedure for antifungal susceptibility testing for Candida spp. of the European Committee on Antibiotic Susceptibility Testing (EUCAST) and four commercial techniques

“…A significant use of reference procedures is to provide a standard from which other methods can be developed and compared. Many studies have analysed the correlation between the NCCLS procedure and various commercially available systems [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], including some suitable for susceptibility testing of Candida spp. However, only one study [25] has compared the EUCAST procedure with commercial systems.…”

Evaluation of the Fungitest Kit by Using Strains from Human Immunodeficiency Virus-Infected Patients: Study of Azole Drug Susceptibility

“…Fungitest (Sanofi-Pasteur, Marnes la Coquette, France), presented in the form of a microplate, is one of them. The Fungitest kit was evaluated by Davey et al (4) with different clinical isolates. Their results indicated that few strains were resistant to FLCZ (6.5%) and ITCZ (5%).…”

Comparative Evaluation of PASCO and National Committee for Clinical Laboratory Standards M27-A Broth Microdilution Methods for Antifungal Drug Susceptibility Testing of Yeasts

“…One study found FUNGITEST to be an unacceptable alternative method on the basis of its misclassification of azole-S-DD and azole-resistant isolates of several Candida spp. as susceptible (2). A second evaluation reported that the MICs determined with the FUNGITEST were in good agreement with the MICs determined by the NCCLS M27-A method, ranging from 100% agreement for amphotericin B to 76.7% agreement for itraconazole when testing was done with Candida spp.…”

“…recovered during prolonged treatment with this agent correlate with therapeutic failure (8,11). Previous evaluations of commercially available antifungal drug susceptibility test methods have included colorimetric broth microdilution methods (Sensititre, Westlake, Ohio, and ASTY, Kyokuto Pharmaceutical Industrial Co., Ltd.) (3,12,20), a noncolorimetric broth breakpoint testing system (FUN-GITEST; Sanofi Diagnostics Pasteur, Paris, France) (2,21), and an agar diffusion system (E-test; AB Biodisk, Solna, Sweden) (4,23). The results suggest that the Sensititre and ASTY colorimetric broth microdilution methods are suitable alternatives for routine antifungal susceptibility testing of Candida spp.…”

“…To address the need for simpler and more efficient testing methods, various commercial methods have been developed and evaluated including colorimetric broth microdilution methods (3,12,20), breakpoint testing methods (2,21), and agar diffusion methods (4,23). Likewise, the PASCO Division of Becton-Dickinson has developed a commercially available broth microdilution panel for the in vitro susceptibility testing of antibacterial agents which has been evaluated on a number of occasions (10,19,22).…”