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A simple electrophoretic method for yeast identification was evaluated. Whole cells were extracted by SDS and the protein profiles obtained in SDS-PAGE after Coomassie blue staining were compared for 52 strains from 9 species of yeast or yeast-like fungi commonly isolated from man (Candida albicans, C. glabrata, C. guilliermondii, C. krusei, C. parapsilosis, C. pseudotropicalis, C. tropicalis, Geotrichum candidum, Saccharomyces cerevisiae). The corresponding patterns showed 30 to 45 polypeptides in the range 95-20 kDa and were clearly different for the 9 species. No differences could be detected between strains from the same species. The characteristic patterns were obtained within 24 h allowing rapid identification of the most commonly encountered clinical yeast isolates.

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The use of rRNA gene restriction fragment length polymorphism analysis (ribotyping) to subtype Streptococcus pyogenes strains was investigated. Sixty-eight S. pyogenes strains, including 17 reference strains and 51 isolates from blood, acute or chronic pharyngitis, and food-borne outbreaks, were characterized by determination of both their rDNA restriction fragment length polymorphism profiles and their serotypes (T and M). Total DNA was cleaved with five selected restriction enzymes and then probed with a digoxigeninlabeled stretch of 1,063 bp hybridizing with 16S rRNA genes. Fifteen and nine distinct patterns were generated with Sacl and XhoI, respectively, and five patterns were generated with each of the three additional restriction enzymes. With the combination SacI-XhoI, a total of 21 distinct ribotypes were obtained among the 68 isolates. This number was not increased by the results obtained with the other restriction enzymes. All strains tested were typeable. All isolates from each food-borne outbreak belonged to the same ribotype, and all isolates (preand posttreatment) from each child with chronic pharyngitis also belonged to the same ribotype, suggesting antibiotic treatment failures. A discriminatory index was calculated for the 47 isolates which were epidemiologically unrelated, using the Hunter-Gaston formula. This index reached 0.955 when the combination SacI-XhoI was used, showing the good discriminatory power of this typing method. Therefore, ribotyping proved to be a molecular method of interest to subtype S. pyogenes. Moreover, there was some correlation between ribotyping and serotyping, as several ribotypes were related to a unique distinct M serotype.