Anti-Fungal Sensitivity Testing

Use(s): Determination of the in vitro sensitivity of yeast isolates.

Description: Testing by CLSI M44Adisc diffusion (fluconazole, voriconazole) or microbroth dilution (fluconazole, itraconazole, voriconazole, amphotericin B, flucytosine, caspofungin, posaconazole and ketoconazole). Specific antifungal(s) tested depend on the identity and source of the isolate and the clinical details supplied. Microbroth dilution testing against is undertaken where indicated by isolate identity, disc diffusion results, or where requested specifically. The identity of the yeast isolate is always confirmed or carried out on isolates sent for sensitivity testing.

Specimen: Yeast isolates, ideally on a Sabouraud agar slope in a bijou or universal tube.

Results: Susceptible, Intermediate/Susceptible-dose dependent, Resistant (where breakpoints have been established). If microbroth dilution testing is carried out, a Minimum Inhibitory Concentration (MIC) can be reported.

Mean Turnaround Time: 9 days (90% within 14 days).

Notes: Infections with C. krusei should not be treated with fluconazole, as this organism is intrinsically resistant; sensitivity testing for moulds is indicated only rarely - please contact the laboratory if advice on this is required; because of limitations in the microbroth method used, a small number of isolates are referred to another laboratory for testing.

Page updated: 11/01/2011 | Updated by: Kevin Roberts