THE SURVIVAL OF STRAINS OF ENTERIC BACILLI IN THE BLOOD STREAM AS RELATED TO THEIR SENSITIVITY TO THE BACTERICIDAL EFFECT OF SERUM

Abstract

It was determined that rabbit serum was bactericidal in vitro for the same strains of gram-negative enteric bacilli as was human serum. Pairs of bacterial strains, one member of which was sensitive to killing by serum and one resistant, were selected. These pairs of strains were injected intravenously into rabbits in nearly equal amounts and the rate of disappearance of each noted. In 10 experiments utilizing 5 bacterial combinations, the resistant strain was cleared at a slightly slower rate. In 6 instances bacteremia was present 24 hours following injection. Ordinarily the resistant strain outnumbered the sensitive about 10 to 1 and in one instance only the resistant strain was present. It is concluded that the heat-labile bactericidal properties of serum play a minor but perhaps important role in clearing the blood stream of bacteria.