Análisis de métodos fenotípicos para la diferenciación de Candida dubliniensis y Candida albicans. Propuesta de una secuencia de identificación.

Abstract

Analysis of phenotypic methods for differentiation of Candida dubliniensis and Candida albicans. Proposal of an identification sequence. Candida dubliniensis is an emerging yeast pathogen described in 1995. C. dubliniensis and C. albicans can be misidentified because these species share multiple phenotypic characteristics. In this work, different methods were evaluated in order to establish an inexpensive and specific procedure to phenotypically differentiate these species. We evaluated the clamidoconidia production in 5 different Introducción En 1995, Sullivan y colaboradores descri- bieron una nueva especie del género Can- dida relacionada filogenéticamente con C. albicans y asociada con lesiones orales recurrentes en pacientes VIH + de Dublin (Irlanda), a la que denominaron C. dubli- niensis (1-6). Posteriormente, esta espe- cie fue aislada de otros tipos de muestras como orina, sangre, heces, tracto respira- torio, vagina, sistema nerviosos central y piel tanto de pacientes VIH+ como VIH- (5, 7-13). En la actualidad, C. dubliniensis es considerada una levadura de distribución cosmopolita y un constituyente minoritario de la micoflora humana y ambiental (4, 14). Debido al aumento de la incidencia de C. dubliniesis en los últimos años, se con- media (tobacco agar, corn meal agar, tobacco tween 80 agar, corn meal tween 80 agar and tomato-carrot agar), lipase activity, D-Xilose assimilation, growth in hypertonic Sabouraud broth and thermotolerance. We concluded that the addition of tween 80 to the agarized media was essential to differentiate C. albicans from C. dubliniensis by clamidoconidia production. Moreover, the tobacco tween 80 agar could be utilized as a media for primary isolation from clinical samples for the evaluation of C. albicans and C. dubliniensis mixed infections. We propose the use of 3 of these methods (lipase activity, tobacco tween 80 agar and growth in hypertonic Sabouraud broth) used sequentially for the differentiation of C. albicans and C. dubliniensis with almost 100% specificity.