DNA SUBTYPES AND FLUCONAZOLE SUSCEPTIBILITIES OF CANDIDA-ALBICANS ISOLATES FROM THE ORAL CAVITIES OF PATIENTS WITH AIDS

Sixty-two Candida albicans isolates from the oral cavities of 28 patients with AIDS who were receiving fluconazole therapy were typed by restriction endonuclease analysis followed by pulsed-field gel electrophoresis; these isolates were then tested for fluconazole susceptibility by a standard broth dilution method. Sequential isolates (range, 2-4) were evaluated for 22 patients; only one isolate was evaluated for six patients. DNA subtyping revealed a total of 37 different DNA subtypes. Twelve (54.5%) of 22 patients with multiple episodes of oropharyngeal candidiasis were infected with a single DNA subtype throughout the observation period. Ten (45.5%) of 22 patients with multiple episodes of oropharyngeal candidiasis were infected with two or three DNA subtypes during the observation period. In vitro susceptibility tests revealed that MICs of fluconazole ranged from less than or equal to 0.125 mu g/mL to 64 mu g/mL, with an MIC(50) of 0.5 mu g/mL and an MIC(90) of 4 mu g/mL. A significant increase in the MICs (fourfold or greater) of fluconazole for sequential C. albicans isolates was found for 66.6% of the patients infected with a single DNA subtype and for 50% of the patients infected with multiple DNA subtypes. Despite a limited number of patients and isolates, our data suggest that C. albicans isolates that are susceptible to fluconazole at MICs of greater than or equal to 8 mu g/mL in vitro will be less susceptible in vivo to standard doses (100-200 mg/d) of this drug.