Background: Oropharyngeal candidiasis and antifungal drug resistance are major problems in HIV positive patients. The increased reports of antifungal resistance and expanding therapeutic options prompted the determination of antifungal susceptibility profile of Candida species isolates in Iranian patients living with HIV/AIDS (PLWHA) in the present study.

Methods: One hundred fifty oral samples from Iranian HIV positive patients were obtained and cultured on CHROMagar and Sabouraud's dextrose agar. All isolates were identified according to assimilation profile, germ tube, colony color and other conventional methods. Disk diffusion testing and Broth Microdilution of six antifungal agents were performed according to the methods described in CLSI.

Results: Candida albicans (50.2%) was the most frequent isolated yeast, followed by C. glabrata (22%). Non-Candida albicans species were isolated from 71 (61%) positive cultures. 25.7% of Candida albicans isolates were resistant to fluconazole (MIC≥64 µg/ml) as were 21.9% and 16.4% to ketoconazole and clotrimazole (MIC>0.125 µg/ml), respectively. Resistance to polyene antifungals including amphotericin B and nystatin, and caspofungin were scarce. 57.7% of candida glabrata isolates were resistant to fluconazole, 31% to ketoconazole and 35% to clotrimazole.

Conclusion: Screening for antifungal resistant candida isolates by disk diffusion or broth dilution methods in clinical laboratories is an ideal surveillance measure in the management of oral thrush in patients with HIV/AIDS. Although nystatin is widely used in clinical practice for HIV positive patients, there was no evidence of enhanced resistance to it. Regarding no resistance to caspofungin, its administration is suggested.