Experimental Bacteremia in Normal and Irradiated Rats †

A common finding in animals which have suffered severe radiation injury is invasion of the blood stream by bacilli normally found in the intestinal tract.' Accordingly, it is generally conceded that one of the significant aspects of such injury is weakening of the normal barrier which prevents the development of infection by micro-organisms that ordinarily exist harmlessly in the bowel. This bacteremia could be due to one or more of the following: (i) continuous passage of large numbers of bacteria from the bowel into the blood stream, (ii) impaired function of the mechanism which normally effects the removal of bacteria from the circulation, or (iii) escape of a few organisms from the bowel with establishment of infection in other parts of the body and bacteremia as a result of that infection. We are reporting the results of experiments which have a bearing on this subject.