Effect of antifungal treatment on the prevalence of yeasts in HIV-infected subjects

Abstract

Oral candidiasis, the most common opportunistic infection in patients with HIV infection, is usually associated with Candida albicans. Several factors may influence the carriage of Candida, including immunocompromised conditions and HIV infection, colonization by yeasts from different geographical areas and antimycotic treatment. This study investigated the Candida carrier rate, level and types of yeast in HIV-positive and -negative subjects, and the effect of previous exposure to antifungal drugs on the level of yeasts in HIV-positive patients in Gauteng, South Africa. Unstimulated saliva was collected from 332 HIV-positive patients and 100 HIV-negative subjects and cultured for yeasts. The number and species of yeast were determined. HIV-positive patients who carried yeasts were divided into two groups depending upon their previous antifungal drug exposure, and the level of Candida carriage in each group was compared. The Candida carrier rate in the HIV-positive patients (81.3 %) was slightly higher than previously reported and significantly higher (P<0.001) than in the HIV-negative group (63 %). The carrier rate in the HIV-negative group was also higher than in earlier studies. Fourteen per cent of the HIV-positive patients carried more than 10 000 c.f.u. ml−1 whereas none of the HIV-negative subjects carried this large a number of yeasts (P<0.001). Seventy per cent of the yeasts were identified as C. albicans and approximately 30 % as non-albicans species. In conclusion, the Candida carrier rate is higher in the South African population than elsewhere. HIV-positive patients carry more and a greater variety of yeasts than HIV-negative subjects. Exposure to antifungal drugs has no effect on the level of yeast carriage in HIV-positive patients.