Identification of Candida dubliniensis in a diagnostic microbiology laboratory

Candida dubliniensis is an emerging yeast pathogen isolated mainly from immunocompromised patients. As molecular tests are currently unsuitable for use in routine diagnostic laboratories, we compared a variety of phenotypic techniques for differentiating C. albicans and C. dubliniensis.The tests included: colony colour on CHROMagar™ Candida medium; growth at 37 °C and 45 °C; ability to produce germ tubes and chlamydospores; and the Auxacolor® system.The organisms included 105 isolates previously identified as C. albicans, 10 reference strains of C. albicans, 2 reference strains of C. dubliniensis and 102 fresh clinical isolates identified as C. albicans. None of the tests alone was satisfactory but a combination of 3 tests may be suitable for presumptive identification of C. dubliniensis.