Genetic similarity and maintenance of Candida albicans strains from a group of AIDS patients, demonstrated by DNA fingerprinting.

By using the computer-assisted Dendron system to analyze the patterns of Southern blots probed with the repetitive sequence Ca3, we have compared oral isolates of Candida spp. from a group of 11 nonhospitalized patients with AIDS suffering from recurrent episodes of oral thrush in Leicester, England, with oral isolates from a group of control individuals. Genetic diversity among the AIDS strains was significantly reduced compared with that of control strains. In addition, the same strains persisted through recurrent infections in patients with AIDS. Although AIDS strains were genetically less diverse than either control strains or oral commensal strains analyzed in previous studies, the majority did not form a genetically distinct group. The results of this study suggest that in the majority of patients with AIDS in this group from Leicester, original commensal strains were replaced, replacement occurred early in the manifestation of AIDS, and replacement occurred only once.