Nutrition of the Host and Natural Resistance to Infection

Abstract

The property of a diet of whole wheat and whole dried milk to promote a higher survival rate among a stock of heterogenetic, outbred W-Swiss mice subjected to S. enteritidis infection, over that promoted by a "synthetic" diet, has been shown to be a function of the infecting bacterial population. Broth cultures so prepared as presumably to yield S. enteritidis organisms of uniform character have consistently failed to reveal an effect of diet on natural resistance, even though the parent bacterial populations revealed a dietary effect. The dietary difference effect on natural resistance could not be demonstrated with an avirulent culture of S. typhimurium, or with a freshly prepared virulent culture of S. typhimurium presumably uniform in character. The dietary effect on natural resistance was demonstrated by employing a 1:1 mixture of avirulent and virulent cultures of S. typhimurium.

Cellular Products Affecting the Establishment of Bacteria of Different Virulence

“…This phenomenon can be explained on the basis that there is insufficient time prior to death caused by the less virulent type to permit the selective establishment of the more threonine-resistant, more virulent cell type that arises at a relatively low rate (1 X If a few cells of the latter type are initially present, however, they will be selected immediately after infection of threonine-treated animals. These observations provide a striking parallel to earlier findings of Schneider (1946) regarding the necessity of a heterogeneous parasite population for the production of nutritional modifications of the susceptibility of mice to salmonellosis. The observations on the selective effects of threonine also suggest that normally existing or nutritionally modified differences in the amino-acid levels of tissues might affect the susceptibility of the host.…”

Some Physiopathological Parameters of Natural Resistance to Infection in Murine Salmonellosis

“…From this selection it follows that we are concerned with "natural resistance," a phenomenon for which several parameters have been previously identified and others suggested. For example, in mouse salmonellosis, predicted differences in host survivorship can be arranged by either genetic (1,2) or nutritional (3)(4)(5) means. In the present investigation we have elected the genetic arrangement of host differences in survivorship.…”

Nutrition of the Host and Natural Resistance to Infection

“…Further evidence that the laboratory culture of MT-1 was not homogeneous, but heterogeneous, was obtained in our laboratory in 1944 (2).…”