Mechanism of Bacteriophage Action in Staphylococcus Bacteremia. ∗

Abstract

Four young rabbits, 1100 to 1320 gm. in weight, were inoculated intravenously with a suspension of staphylococcus which had been isolated from human bacteremia. Each animal received an intravenous injection of 2 cc, equivalent to 5400 million living staphylococci. One rabbit was sacrificed 155 minutes after inoculation. Sections of spleen and liver revealed phagocyted leucocytes and partly disintegrated nuclear granules. Only one pair of cocci was recognized within a Kupffer cell after considerable search. A second animal was sacrificed 238 minutes after inoculation. Sections of the spleen revealed many phagocyted granules and nuclear fragments but no definite bacteria. In the liver, however, there were distinct and definite cocci within the somewhat swollen Kupffer cells. The third rabbit received an intravenous injection of 2 cc. undiluted asparagin staphylococcus bacteriophage 103 minutes after the bacterial inoculation and was sacrificed 131 minutes later, or 234 minutes after the bacterial inoculation. Sections of the spleen of this animal showed numerous phagocyted nuclear granules in the marginal zones about the splenic follicles and along with them poorly differentiated cocci in small numbers. In sections of the liver the phagocyted cocci were very abundant and distinctly differentiated, decidedly more abundant than in the liver of the second animal. The fourth rabbit received a similar dose of bacteriophage 106 minutes after bacterial inoculation and was sacrificed 89 minutes later or 195 minutes after the bacterial inoculation. Sections of the spleen of this animal contained unmistakable groups of micrococci within the reticular cells about the follicles and in some locations these cocci were numerous. In the liver also, the Kupffer cells contained abundant phagocyted cocci. The observations indicate that one immediate effect of intravenous injection of bacteriophage in bacteremia is to favor more rapid phagocytosis of the bacteria which are circulating in the blood.