Guadalupe Charriel | PubMed Health

PubMed2005

Susceptibility of filamentous fungi to voriconazole tested by two microdilution methods.

The growing number of fungal infections, coupled with emerging resistance to classical antifungal agents, has led to the development of new agents, among them voriconazole. Susceptibility to voriconazole was tested by two microdilution techniques: the National Committee for Clinical Laboratory Standards reference method M38-A and a colorimetric method, Sensititre YeastOne. The study tested a total of 244 isolates: 223 Aspergillus (136 Aspergillus fumigatus, 37 A. niger, 26 A. terreus, 16 A. flavus, 7 A. nidulans, and 1 A. ustus), 14 Fusarium (8 Fusarium moniliformis, and 6 F. oxysporum), 6 Scedosporium apiospermum, and 1 Rhizomucor pusillus strain and four control strains (Candida parapsilosis ATCC 22019, C. krusei ATCC 6258, A. fumigatus ATCC 204305, and A. flavus ATCC 204304). For all tested species except one F. moniliforme strain and R. pusillus, the MIC, the MIC at which 50% of the isolates are inhibited (MIC(50)), and MIC(90) ranges of </=1 microg/ml were obtained for voriconazole, indicating excellent activity against these species. The high rate of agreement between the two methods used (97 to 99%) suggests that the Sensititre YeastOne colorimetric method may be a valuable tool for determining the susceptibility of filamentous fungi to voriconazole.

Antifungal Agents↗

PubMed2004

Comparison of two microdilution methods for testing susceptibility of Candida spp. to voriconazole.

The growing number of fungal infections, coupled with emerging resistance to classical antifungal agents, has led to the development of new agents, among them voriconazole. Susceptibility to voriconazole was tested by using two microdilution techniques: the reference method described in National Committee for Clinical Laboratory Standards document M27-A2 and a colorimetric method, Sensititre YeastOne. A total of 272 Candida isolates (132 of Candida albicans, 62 of C. parapsilosis, 33 of Candida glabrata, 21 of C. krusei, 15 of C. tropicalis, and 9 of C. lusitaniae) and two control strains (C. parapsilosis ATCC 22019 and C. krusei ATCC 6258) were tested. There was a high rate of agreement between the two methods used (97 to 100%).

Antifungal Agents↗

PubMed2003

[CHROMAgar Candida with fluconazole: comparison with microdilution techniques].

INTRODUCTION: The increasing incidence of fungal infections and the reported emergence of resistance to antifungal agents call for the development of techniques for in vitro measurement of antifungal susceptibility that will enable prediction of clinical outcome in patients suffering from these infections. METHODS. Susceptibility to fluconazole was tested in 156 clinical yeast isolates (109, Candida albicans; 19, C. parapsilosis; 12, C. glabrata; 11, C. tropicalis; 2, C. krusei; 1, C. pelliculosa; 1, C. lambica, and 1, Saccharomyces cerevisiae) and two control strains (C. krusei ATCC 6258 and C. parapsilosis ATCC 22019) using a simple screening method, CHROMAgar Candida with fluconazole (8 micro g/ml). This method was compared with two broth microdilution techniques: the reference method (NCCLS, document M27-A) and Sensititre(TM) YeastOne. RESULTS: Sensititre(TM) YeastOne showed close agreement with NCCLS M27-A results for all species (C. albicans and non albicans). CHROMAgar Candida with fluconazole (8 micro g/ml) yielded results matching those of the two broth microdilution methods for sensitive strains and strains highly resistant to fluconazole (C. krusei and C. glabrata), but performed less well with strains displaying dose-dependent susceptibility. CONCLUSION: These data suggest that CHROMAgar Candida with fluconazole (8 micro g/ml), appears to be a rapid, simple and sensitive screening method for detection and identification of fluconazole-susceptible and -highly resistant yeasts. However, additional methods should be used to determine whether positive growth in this medium is due to resistant strains (MIC > or = 64 micro g/ml) or to strains displaying dose-dependent susceptibility (MIC 16-32 micro g/ml). The usefulness of CHROMAgar Candida with fluconazole depends on the sample source and the species under study.

Antifungal Agents↗