The Survival of Staphylococci within Human Leukocytes* by David E. Rogers,~ M.d., Ai~d

The mechanisms whereby certain staphylococci are capable of initiating infection in man are poorly understood. Numerous investigations of staphylococci isolated from human infections have characterized certain biologic properties of these microorganisms as related to their pathogenicity. I t has been considered that the local initiation of staphylococcal infection is aided by the necrotizing action of exotoxin produced by certain strains (1, 2). I t has also been suggested that this process is promoted by the destruction of leukocytes as a consequence of the elaboration of "leukocidin" by staphylococci (3, 4). I t is recognized, however, that staphylococci which elaborate no demonstrable exotoxin may produce local lesions indistinguishable from those produced by strains which elaborate a potent toxin (5). Moreover, immunization against toxin and leukocidin fails to prevent the development of staphylococcal abscesses, although the immunity may serve to modify certain of the other manifestations of the experimental infection (6). A direct relationship appears to exist between the ability of a particular strain of staphylococcus to produce coagulase and the pathogenicity of that strain for man. The precise nature of this relationship, however, has not been clearly delineated. Spink and Vivino have shown (7) that coagnlase-positive (i.e. coagulase-producing) strains of staphylococcus survive incubation in whole blood (human) whereas coagnlase-negative strains fail to survive. The role of the coagulase mechanism in this is difficult to interpret, however, inasmuch as the phenomenon was observed in defibrinated blood which might be expected to provide very little if any fibrinogen as substrate for the action of coagnlase. Hale and Smith (8) have suggested that the action of coagulase may serve to protect staphylococci from phagocytosis and thereby aid in the initiation of infection. In support of this hypothesis, these investigators have reported