J Clin Pathol Qual Control.  1998 Dec;20(2):367-372.

Fluconazole E-test in Yeasts and Susceptibility Pattern

• Lee CK
• Jin H
• Ma KR
• Kim YK
• Lee KN

Abstract

BACKGROUND: The growing number of reports on resistance of fungi have been made due to the increasing use of antifungal agents. E-test is a rapid, and easy-to-perform in-vitro susceptibility testing method to guide an antifungal therapy. Since E-test results are affected by many environmental factors, we tried to determine the effect of media, incubation time, and inoculum density in fluconazole E-test, and to know the susceptibility pattern of yeasts isolated from clinical specimens. METHOD: MIC endpoints of E-test for fluconazole susceptibility were read after 24 hr and after 48 hr for Candida parapsilosis ATCC 90018, Candida glabrata ATCC 90030, Candida albicans ATCC 90028, Candida albicans ATCC 90029 on RPMI agar, Saubouraud dextrose agar (SDA), and casitone agar. We used 0.5 McFarland standard yeast suspension and its 1:10 dilution solution. E-test for 63 clinical isolates also performed after 24 hr on RPMI agar.
RESULTS
After 24 hr, four ATCC strains showed acceptable MIC ranges on RPMI agar, but none on SDA and only one on casitone agar. SAD showed better results after 48 hr. SDA and casitone agar showed better results with 1:10 dilution of 0.5 McFarland standard solution. 6.3% of 63 clinical isolates of yeast was intermediate, and 94.7% of them susceptible.
CONCLUSIONS
It seems that the selection of media is the most important factor in fluconazole E-test and that RPMI media and reading after 24 hr give the best results for fluconazole E-test.

MeSH Terms

Agar
Antifungal Agents
Candida
Candida albicans
Candida glabrata
Fluconazole*
Fungi
Glucose
Yeasts*
Agar
Antifungal Agents
Fluconazole
Glucose