Clonal and spontaneous origins of fluconazole resistance in Candida albicans

The genotypes and susceptibilities to fluconazole of 78 strains of the huma n pathogenic yeast Candida albicans were compared. The strains comprised tw o sets of samples from Durham, N.C.: one from patients infected with the hu man immunodeficiency virus (HIV) and the other from healthy volunteers. For each strain, the MIC of fluconazole was determined by the standard Nationa l Committee for Clinical Laboratory Standards protocol. Genotypes were dete rmined by PCR fingerprinting,vith five separate primers. The analysis revea led little evidence for genotypic clustering according to HN status or body site. However, a small group of fluconazole-resistant strains isolated fro m patients infected with HIV formed a distinct cluster. In addition, two fl uconazole-resistant strains were isolated from individuals who never took f luconazole, one from a patient infected with HIV and the other from a healt hy person. The results suggest both clonal and spontaneous origins of fluco nazole resistance in C. albicans.