Classification of 110 Strains of Staphylococcus aureus.

A collection of strains of Staphylococcus aureus was studied with a view to finding out what relationship, if any, could be detected between the agglutinative grouping and the production of polysaccharide, alpha hemolysin, or leucocidin by the various strains. A number of serological groupings for staphylococci have been described in the literature, the most recent ones being those of Blair and Hallman (1936), Yonemura (1936), Cowan (1938), and Christie and Keough (1940). The classification put forward by Cowan has probably been the most widely adopted, and is the one employed in this study. Of the polysaccharide classifications, the "A" and "B" classification of Julianelle and Wieghard (1935) remains fundamental for pathogenic staphylococci. Thompson and Khorazo (1937) have found three additional groups containing mostly non-pathogenic staphylococci, and Cowan (1938) places pathogenic strains giving irregular polysaccharide reactions into a general class "C". The Julianelle classification is the one employed for the work described in this paper. A staphylococcal leucocidin which destroys rabbit leucocytes was described by Van der Velde (1894) and studied further by Neisser and Wechsberg (1901). More recently (1936) Wright has worked with this Neisser-Wechsberg leucocidin, and she suggests, as do also Valentine (1936) and Proom (1937), that it is identical with staphylococcal alpha-hemolysin. Panton and Valentine (1932), Valentine (1936), and Valentine and Butler (1939), however, have demonstrated that certain strains of staphylococci elaborate a leucocidin which is distinct from the Neisser-Wechsberg type. The Panton-Valentine leucocidin is active against human as well as rabbit leucocytes, thus differing from the Neisser-Wechsberg leucocidin, which does not affect human leucocytes. The two leucocidins also differ in their mode of attack upon the leucocytes. Both cause disintegration of the cell nucleus, but the appearance of the damaged particles is different. Panton-Valentine leucocidin in stronger concentration produces complete disintegration of the cytoplasm. Panton-Valentine leucocidin is the one referred to in this paper. Dr. John E. Blair of the Hospital for Joint Diseases, New York, supplied us with Cowan group I and group III strains, and Dr. Champ Lyons of Harvard Medical School, the group II strain. Dr. L. A. Julianelle of Washington University School of Medicine, Saint Louis, sent us his representative polysaccharide "A" and "B" strains. All the cultures included in the study were isolated from human infections. The origin of the strains is shown in table 1.