Taxonomic studies of micrococci and staphylococci

In the course of 3 years, 274 strains of micrococci and staphylococci were isolated from a variety of habitats, and 132 strains were obtained as pure cultures, mainly from culture collections; this gave a total of 406 strains for taxonomic studies. All 406 strains were examined for a total of 49 morphological and physiological characters, and the strains were compared for characters in common. It would found that strains with practically all combinations of characters existed, from the coagulase positive, biochemically active staphylococci, through many intermediate groupings to the biochemically weak yellow and red micrococci; a classification scheme based on a few arbitrarily ohosen main characters, as is the tradition in this group of bacteria, would be entirely artificial. After discussing some of these main characters, and finding practically all of them unsuitable as important criteria for classifying the 406 strains of micrococci and staphylococci, I decided to adopt the Adansonian approach to classification, and treated 49 morphological and physiological character as being equal. As I expected, the results of this Adansonian classification demonstrated that there was no clear division of the 406 strains into 2 main groups, equivalent to the genera Microcccus and Staphylococous, but there was a division into very many small groupings, the majority of which contained only one strain. The most important conclusion drawn from this scheme was that all micrococcus and staphylococci should be placed into one genus - Micrococcus, and it seemed unlikely that further division of this genus into natural groupings by morphological and physiological characters was possible. Consequently, other characters, in particular those demonstrated by electrophoretic methods, were examined for their suitability in classification. I studied the isozyme bands, detected by specific colour reactions in acrylamide gol slices, which contained electrophoresed cell contents of the 406 micr