Laboratory identification and sensitivity testing of yeast isolates

Abstract

Methods used for identification and sensitivity testing of yeasts are presented. Identification depends on both morphologic features and biochemical characteristics. The germ tube test is a simple test for the identification of the commonest yeast pathogen, Candida albicans. Species not identified by this method can be identified by means of several other tests, the most important being the carbohydrate assimilation test. Several kits are commercially available and most appear to be satisfactory. Antifungal susceptibility tests are not standardized, and results are often subject to considerable variation. Until improved methods are developed, it might be advisable that smaller laboratories only do a preliminary screening test for flucytosine susceptibility and, if indicated, also for amphotericin B susceptibility. Important isolates should be sent to laboratories with a special interest in antifungal susceptibility testing for more extensive testing.