Abstract
Oral candidiasis is the most common oral manifestation of HIV infection, but it is unclear whether, in addition to immune dysfunction, this predisposition is related to changes in the biotypes or genotypes of infecting Candida. The objective of this study was to compare the genetic variability of Candida albicans isolated from 50 HIV infected patients (25 Candida carriers and 25 candidiasis patients) and 50 age and candidiasis matched control subjects. Candidal DNA was extracted, purified, cleaved with Bg/II and electrophoresed on agarose gels to reveal restriction fragment length polymorphism (RFLP) banding patterns. Analysis of the RFLP patterns revealed a total of 16 genotypes that could reproducibly be identified: designated genotypes A to P. Genotypes A and B predominated, accounting for 48 per cent and 30 per cent, respectively, of all isolates analysed. C. albicans isolated from control subjects showed comparatively little genetic diversity, regardless of the presence of candidiasis. In contrast, isolates from HIV infected patients indicated an increase in the number of unique, genetically diverse genotypes and a reduction in the proportion of genotype B isolates, especially in HIV candidiasis patients (P < 0.05). This apparent selection of Candida isolates in HIV infection may be associated with the emergence of strains with an enhanced ability to cause disease in the presence of immune dysfunction.