COMPARISON OF 4 MOLECULAR TYPING METHODS FOR EVALUATING GENETIC DIVERSITY AMONG CANDIDA-ALBICANS ISOLATES FROM HUMAN IMMUNODEFICIENCY VIRUS-POSITIVE PATIENTS WITH ORAL CANDIDIASIS

Candida albicans strain delineation by karyotyping, NotI restriction p attern analysis, hybridization with specific probe 27A, and PCR finger printing with the phage M13 core sequence were performed with 30 isola tes from the oral cavities of 30 human immunodeficiency virus (HIV)-in fected patients and 8 reference strains, Within the panel of clinical isolates, 20 were geographically related, although 10 isolates were su sceptible to fluconazole and 10 isolates were resistant to fluconazole . The remaining isolates used in this study were fluconazole resistant and geographically unrelated, A composite DNA type was defined for ea ch of the strains as the combination of types obtained by the four mol ecular methods, By this procedure, a great diversity of DNA types was found among isolates from the oropharynges of HIV-infected individuals with oral candidiasis, This diversity was not reduced when isolates w ere evaluated on the basis of whether they came from the same geograph ical locale and whether they were fluconazole resistant, These data re fute the idea of a clonal origin for fluconazole-resistant strains amo ng HIV-positive patients, Karyotyping was the least discriminatory met hod, yielding 19 DNA types among the 38 strains analyzed. Conversely, hybridization with the 27A probe showed a unique DNA pattern for each of the strains examined in this study, Our results demonstrate that at least two different molecular methods are needed for Candida albicans typing and that there is a great deal of strain variation within the species, irrespective of place of origin or antifungal resistance patt erns.