Simplified Identification of Yeasts by a Serological Technique

A scheme is described for comparison of yeast colonies isolated on normal or selective media or by membrane filtration. By streak culture of each colony, or of a selection of each type of colony, on Oxoid WL medium followed by serological and morphological testing of the cultures, the different species present are detected with minimal effort. Colonies of the same species are identical in appearance, and in serological and morphological properties of the cells; therefore if a complete identification is desired, only one colony need be tested of each type. This saves the effort of fermentation and other tests on a large number of colonies, but results of morphological and serological tests alone normally provide sufficient information for identification of taxonomic groups of yeasts, if not of individual species. Three examples of the use of the method are described: identification of the various yeast species of the sherry flor complex, and identification of yeasts in samples of clean and polluted water.