Activity of fluconazole againstCandida albicansisolates from HIV + patients in a digestive candidosis turkey model

Variation in fluconazole efficacy for Candida albicans strains sequentially isolated from oral cavities of patients with AIDS in an experimental murine candidiasis model

Four strains of Candida albicans, isolated from two patients with AIDS who had undergone prolonged fluconazole therapy for oral candidiasis, were studied in a model of disseminated murine candidiasis. Pre- and posttreatment isolates from each patient were genetically related, and the fluconazole MICs for the strains had increased significantly, from 0.25 to 32 micrograms/ml for the strains isolated from patient 1 and from 1.0 to 16 micrograms/ml for the strains isolated from patient 2. Mice were infected intravenously and were treated orally with fluconazole. For survival studies, mice were treated from day 1 to day 10 postinfection and were observed through day 30. The fluconazole dosages were as follows: 0.25, 0.5, 1.0, and 5.0 mg/kg of body weight twice a day. For tissue burden studies, two groups of mice (each group received fluconazole at 0.25 or 5.0 mg/kg) were treated from day 1 to day 7 and were sacrificed 1 day later for quantitative tissue cultures of the spleen and both kidneys. For pretreatment isolates from both patients, all fluconazole dosing regimens were effective at prolonging survival compared with the survival of the control groups. For posttreatment isolates, only fluconazole at 5.0 mg/kg was effective at prolonging survival. Both fluconazole dosing regimens used in the tissue burden studies significantly reduced the counts of the pretreatment isolate from patient 1 in the spleen and kidney, while fluconazole at 5.0 mg/kg was effective at reducing the counts of the posttreatment isolate. For both isolates from patient 2, only fluconazole at 5.0 mg/kg was effective at reducing the counts in the spleen and kidney. The study indicates that C. albicans mutation to resistance to fluconazole may play a critical role in fluconazole-refractory oral candidiasis in AIDS patients.

Relationship between fluconazole sensitivity of Candida albicans isolates from HIV positive patients and serotype, adherence and CD4+ lymphocyte count

The sensitivity of fluconazole, serotype and adherence to buccal epithelial cells of 46 Candida albicans isolates was studied in vitro. Strains were isolated from 18 HIV-positive patients with variable CD4+ lymphocyte counts who were receiving long-term fluconazole therapy. Results showed that sensitivity to fluconazole correlated with serotype. Of the sensitive isolates 81.5% were serotype A and 18.5% serotype B, whereas of the resistant isolates 37.5% were serotype A and 62.5% serotype B. Sensitivity to fluconazole also correlated with adherence capacity, resistant isolates showing slightly less adherence to buccal epithelial cells than sensitive isolates. Weakly adherent isolates represented 87% of resistant isolates and only 63% of sensitive isolates. Resistant strains were isolated in highly immunocompromised patients. All strains isolated in patients with CD4+ lymphocyte counts above 200 lymphocytes/microliters were sensitive, whereas intermediate and resistant strains were isolated in patients with counts below 200 lymphocytes/microliters. Statistical analyses showed no correlation between adherence of isolates to buccal epithelial cells and CD4+ lymphocyte counts.