Genotyping fluconazole resistant Candida albicans from human immunodeficiency virus positive patients

Abstract

Pulsed field gel electrophoresis (PFGE) after restriction with the enzyme sfiI, restriction fragment length polymorphism (RFLP) with the enzyme EcoRI, random amplification of polymorphic DNA (RAPD) with the probes 5′−3′ GCTGGTGG and GCG CAC GG and Southern blot hybridization with the species specific DNA probe 27A were used to type 19 fluconazole resistant, MIC ≥ 12.5 μg/ml, isolates of Candida albicans. These were associated with ten HIV positive patients where there had been a clinical failure on fluconazole and who were present concurrently in Monsall Hospital. Seventeen of the isolates were biotype 1. This study demonstrated that each patient was infected by a strain with a unique genotype and there was no evidence of crossinfection. Toothbrushes and, for fluconazole sensitive isolates, bed cups were heavily contaminated emphasising the need for their safe disposal. Low discrimination was produced by PFGE (2 types) based on changes in band pattern after variation in the unstable ribosomal chromosome had been excluded. Better discrimination was obtained with RFLP (10 types) RAPD (10 types) PFGE incorporating changes in band width and position (11 types) of SfiI digestion (11 types) and by Southern blot hybridization (12 types).