Esma KAYA, Hatice ÖZBİLGE

Determination of the effect of fluconazole against Candida albicans and Candida glabrata by using microbroth kinetic assay*

To evaluate the antifungal activity of a model antifungal (fluconazole) against Candida albicans (ATCC 90028) and Candida glabrata (RSKK 04019) strains using a microbroth kinetic assay based on continuous monitoring of changes in the optical density of fungal growth. Recently, antifungal susceptibility testing has become more important because of the increasing incidence of both fungal infections and antifungal drug resistance. Materials and methods: The optical growth densities of C. albicans and C. glabrata in the presence of increasing concentrations of fluconazole were measured every 15 min for 24 h at 35 °C, using a multidetection microplate reader at 405 nm. The turbidimetric growth curves of these strains were obtained, and the minimal inhibitory concentration (MIC) values for fluconazole were determined with this kinetic assay. Furthermore, the conventional broth microdilution method was performed according to Clinical and Laboratory Standards Institute reference method M27-A2. Results: MIC90 values for fluconazole were determined as 0.31 mg/mL for C. albicans and 16.32 mg/mL for C. glabrata. Conclusion: Using kinetic procedures, the effects of antifungal drugs on target yeasts can be determined at any desired time-point of the incubation period.

Anahtar Kelimeler:

Key words: Candida, fluconazole, minimal inhibitory concentration, growth curve, optical density, kinetic assay

Determination of the effect of fluconazole against Candida albicans and Candida glabrata by using microbroth kinetic assay*

Keywords:

Key words: Candida, fluconazole, minimal inhibitory concentration, growth curve, optical density, kinetic assay,

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Espinel-Ingroff A, Barchiesi F, Cuenca-Estrella M, Fothergill A, Pfaller MA, Rinaldi M et al. Comparison of visual 24-hour and spectrophotometric 48-hour MICs to CLSI reference microdilution MICs of fl uconazole, itraconazole, posaconazole, and voriconazole for Candida spp.: a collaborative study. J Clin Microbiol 2005; 43: 4535-40.
Arthington-Skaggs BA, Lee-Yang W, Ciblak MA, Frade JP, Brandt ME, Hajjeh RA et al. Comparison of visual and spectrophotometric methods of broth microdilution MIC endpoint determination and evaluation of sterol quantitation method for in vitro susceptibility testing of fl uconazole and itraconazole against trailing and nontrailing Candida isolates. Antimicrob Agents Chemother 2002; 46: 2477-81.
Chou HH, Lo HJ, Chen KW, Liao MH, Li SY. Multilocus sequence typing of Candida tropicalis shows clonal cluster enriched in isolates with resistance or trailing growth of fl uconazole. Diagn Microbiol Infect Dis 2007; 58: 427-33.
Meletiadis J, Meis JF, Mouton JW, Verweij PE. Analysis of growth characteristics of fi lamentous fungi in diff erent nutrient media. J Clin Microbiol 2001; 39: 478-84. 8. Meletiadis J, Dorsthorst D, Verweij PE. Use of turbidimetric growth curves for early determination of antifungal drug resistance of fi lamentous fungi. J Clin Microbiol 2003; 41: 4718-25.
Lehtinen J, Jarvinen S, Virta M, Lilius EM. Real-time monitoring of antimicrobial activity with the multiparameter microplate assay. J Microbiol Methods 2006; 66: 381-9.
Hosphental DR, Murray CK, Rinaldi MG. Th e role of antifungal susceptibility testing in the therapy of candidiasis. Diagn Microbiol Infect Dis 2004; 48: 153-60.
Ostrosky-Zeichner L, Rex JH, Pfaller MA, Diekema DJ, Alexander BD, Andes D et al. Rationale for reading fl uconazole MICs at 24 hours rather than 48 hours when testing Candida spp. by the CLSI M27-A2 standard method. Antimicrob Agents Chemother 2008; 52: 4175-7.
Balajee SA, Imhof A, Gribskov JL, Marr KA. Determination of antifungal drug susceptibilities of Aspergillus species by a fl uorescence-based microplate assay. J Antimicrob Chemother 2005; 55: 102-5.