Parity among the randomly amplified polymorphic DNA method, multilocus enzyme electrophoresis, and Southern blot hybridization with the moderately repetitive DNA probe Ca3 for fingerprinting Candida albicans

Abstract

Randomly amplified polymorphic DNA (RAPD) analysis, multilocus enzyme electrophoresis (MLEE), and Southern blot hybridization with moderately repetitive DNA probes have emerged as effective fingerprinting methods for the infectious fungus Candida albicans. The three methods have been compared for their capacities to identify identical or highly related isolates, to cluster weakly related isolates, to discriminate between unrelated isolates, and to assess microevolution within a strain. By computing similarity coefficients between 29 isolates from three cities within the continental United States, strong concordance of the results is demonstrated for RAPD analysis, MLEE, and Southern blot hybridization with the moderately repetitive probe Ca3, and weaker concordance of the results is demonstrated for these three fingerprinting methods and Southern blot hybridization with the moderately repetitive probe CARE2. All methods were also demonstrated to be able to resolve microevolution within a strain, with the Ca3 probe exhibiting the greatest resolving power. The strong correlations demonstrated between polymorphic markers assessed by the four independent fingerprinting methods and the nonrandom association between loci demonstrated by RAPD analysis and MLEE provide evidence for strong linkage disequilibrium and a clonal population structure for C. albicans. In addition, a synapomorphic allele, Pep-3A, was found to be present in all members of one of the three clusters discriminated by RAPD analysis, MLEE, and Ca3 fingerprinting, supporting the concordance of the clustering capacities of the three methods, the robustness of the clusters, and the clonal nature of the clusters.