In vitro antifungal susceptibility testing of filamentous fungi with Sensititre Yeast One^TM

Abstract

Sensititre is a colorimetric microdilution method for in vitro antifungal susceptibility testing based on the M27-A document (National Committee for Clinical Laboratory Standards) for yeasts. Difference between both methods is the presence of Alamar-blue and RPMI 1640 (glucose 2%) as culture medium. Antifungal susceptibility to amphotericin B, fluconazole, itraconazole, ketoconazole and flucytosine, 100 opportunistic filamentous fungi (Aspergillus spp., Fusarium spp., Scedosporium spp.) obtained from pathological samples was determined by the Sensititre method. Induction to conidium and sporangiospore formation at 35 degrees C was used to get inoculum and plates were covered by 1 ml of saline and suspensions were made by gently probing by a sterile loop. Optical densities of the conidial suspensions were adjusted to 80-82% transmittance for Aspergillus spp. and 68-70% for the rest of strains tested. Final inoculum concentration size was 0.4 x 10(4)-5 x 10(4) CFU ml(-1). Readings were made at 72 h of incubation at 35 degrees C; amphotericin B and itraconazole was active against Aspergillus fumigatus with CMI90 1 and 0.5 microg ml(-1), respectively, opposite to Scedosporium prolificans and Scedosporium apiospermum. As it was expected, a CMI90 of 256 microg ml(-1) for fluconazole and CMI90 for flucytosine amounting to 64 g ml(-1) were obtained. Sensititre Yeast One is a useful method and an alternative to reference methods to determine antifungal susceptibility of filamentous fungi for clinical laboratory routine. Correlation with microdilution results is studied. New triazole derivatives should be included as soon as their clinical use will be feasible.

Comparison of the Sensititre YeastOne® Colorimetric Antifungal Panel with the Modified Clinical and Laboratory Standards Institute Broth Microdilution (M38-A) Method for Antifungal Susceptibility Testing of Dermatophytes

“…The main disadvantage of the CLSI M38-A procedure is that the tray preparation is time consuming. In recent years, the usefulness of the Alamar blue and Sensititre YeastOne panels has been evaluated for molds testing, using reference macro-and microdilution methods [1,2,5,[7][8][9][10][11][12] . Therefore, methodologically easier systems, such as Sensititre YeastOne, are a useful method and an alternative to reference methods for determining the antifungal susceptibility of filamentous fungi in routine clinical laboratory.…”

“…Recently, there has been growing interest in the development of a reference method for in vitro antifungal susceptibility testing of dermatophytes [5] , mainly because of the great need for an easier and reproducible method for in vitro susceptibility testing of filamentous fungi which will serve as a guide for selecting and monitoring antifungal therapy. Alternatives to the CLSI method are currently under investigation, and 2 commercial methods, E-Test and Sensititre YeastOne , have been evaluated for both yeast and molds [1,2,5,[7][8][9][10][11][12] .…”

In vitro susceptibility testing of dermatophytes isolated in Goiania, Brazil, against five antifungal agents by broth microdilution method

“…However, infections due to dermatophytes are often associated with relapses after cessation of therapy 20 . By the way, in vitro antifungal susceptibility tests could help to optimize the therapy and to select an effective antifungal agent for this mycosis 3 . A standard method for susceptibility testing of dermatophytes is lacking, but good results of MIC using either broth macrodilution or broth microdilution tests have been obtained in several reports 9,10,12,18 .…”

Cysticidal Activity of Antifungals against Different Genotypes of Acanthamoeba

“…The Sensititre Yeastone plate (TREK Diagnostic Systems, Cleveland, OH) is a microtiter broth dilution plate for antifungal sensitivity testing (17,18). The plate contains seven dried antifungal drugs at 2-fold dilutions (Table 2).…”