Epidemiological analysis of Candida albicans strains by multilocus enzyme electrophoresis.

Genotypic diversity in a collection of 98 isolates of Candida albicans was assessed by multilocus enzyme electrophoresis. Four of the 10 enzyme loci studied were polymorphic. The electrophoretic patterns observed were compatible with those expected for a diploid organism. The 98 isolates were assigned to 14 electrophoretic types, each of which was represented by from 1 to 21 isolates. Samples from various clinical sites of seven bone marrow transplant patients treated in the same unit within a 13-month period were obtained repeatedly. Three patients were found to be colonized with more than one strain. In one patient, flucytosine-resistant strains were isolated after systemic antifungal treatment was started. These isolates had electrophoretic types different from those of the strains that colonized the patient before treatment. There was no evidence that cross-infection between these patients occurred in the hospital. The population structure of C. albicans is discussed in regard to the multilocus genotype data.