Effect of Splenectomy on Bacterium Enteritidis Infection in White Mice

Abstract

It has been well established that removal of the spleen in many species of animals depresses the natural resistance to certain bacterial, protozoan and spirochetal infections.∗ The rôle of the spleen in the maintenance of an acquired resistance to latent piroplasmidae and bacterial infections has been demonstrated in Bartonella muris infection in the rat, in Bartonella canis infection in the dog, in Eperythrozoan coccoides and Bartonella muris infection in the mouse, in infection with Nuttalia equi in the horse, Anaplasmosis in sheep and cattle and Babesia bigeminum in cattle. 3 Removal of the spleen converts a latent infection into manifest disease, often associated with a severe fatal anemia.

Morris and Bullock studied a spontaneous epizootic infection, with Bacterium enteritidis (Gaertner), in their rat colony and noted that splenectomy conspicuously lowers the resistance of the rat to this natural infection. 4 They were unaware, however, of the occurrence of Bartonella muris anemia following removal of the spleen in almost all strains of rats.

In the experiments reported in this communication the effect of splenectomy on the course of a subsequently induced acute bacterial infection, Bacterium enteritidis, was studied in mice free of Epery-throzoan coccoides and Bartonella muris, since latent infections with these microorganisms may become active following removal of the spleen. 2

All the mice used in these experiments were kindly furnished to us by Dr. Leslie T. Webster of the Rockefeller Institute for Medical Research. Two strains of mice were used. The animals of one strain were of a selected stock which had been found in the studies of Dr. Webster to be highly resistant (termed by him, “resistant”) to spontaneous or induced infection with Bacterium enteritidis and pneumococcus.