Mice on inadequate nutritional regimens were found to be more susceptible to various bacterial diseases than mice fed a complete diet containing 15 to 20 per cent casein. The tests of susceptibility included: (a) infections with virulent bacteria; (b) injection of large doses of avirulent coagulase-negative staphylococci; and (c) lethal effects of bacterial endotoxins.
The infection-enhancing effect of nutritional deficiencies could be rendered even more striking by administering the infective inoculum simultaneously with a sublethal dose of endotoxin.
Despite their great susceptibility to infection, malnourished animals retained much of their ability to eliminate bacteria from the blood, liver, spleen, kidneys, and lungs, at least during the early phases of the infectious processes. This was true even when the animals had received endotoxin simultaneously with the infective dose.
The results suggest that under the conditions of the present study, the nutritional state influenced the outcome of infection not primarily by affecting the fate of the pathogens in vivo, but rather by modifying the ability of the host to resist their toxic effects.