CHARACTERIZATION OF GENETICALLY DISTINCT SUBGROUP OF CANDIDA-ALBICANSSTRAINS ISOLATED FROM ORAL CAVITIES OF PATIENTS INFECTED WITH HUMAN-IMMUNODEFICIENCY-VIRUS

During the course of a study of oral Candida albicans strains from 60 human immunodeficiency virus-infected patients over a 2.5-year period, 18 of the 295 C. albicans isolates had genomes that failed to hybridi ze with a C. albicans-specific DNA probe (27A). These strains were ger m tube positive and chlamydospore positive and were identified as C. a lbicans by the ID 32C test (API Systems, Montlieu, France). These stra ins were analyzed for the presence of two other C. albicans-specific D NA segments by PCR. The first was a C. albicans 1,348-bp species-speci fic sequence, and the second was a 1,059-bp C. albicans repetitive ele ment, The probe 27A-hybridizing strains yielded PCR products which dif fered from those of the nonhybridizing strains. Five of these genetica lly atypical C. albicans strains and 98 of the C. albicans strains wer e then analyzed for purported virulence factors. The genetically atypi cal C. albicans strains, in comparison with typical C. albicans strain s, produced greater amounts of extracellular proteinase (P = 0.038, St udent's t test), adhered to a greater degree to buccal epithelial cell s (P = 0.018, Student's t test), and were less susceptible to the anti fungal drug 5-flucytosine (P = 0.0003, Mann-Whitney test). Analysis of these strains with other common antifungal drugs showed no statistica lly significant variation in susceptibility. The results of this study indicated that these genetically atypical C. albicans strains possess increased virulence in comparison with typical C. albicans strains.