Susceptibility to Infection as a Function of Postirradiation Time Following Oral Challenge

Abstract

Summary Total body x-irradiation (300–350 r) resulted in increased susceptibility of mice to infections induced by the gastric instillation of Streptococcus hemolyticus (Group C), paracolon bacilli, Salmonella typhimurium and Escherichia coli on the first, third, fourth, and fifth postirradiation days. No difference in mortality was observed if mice were challenged at later dates (between the sixth and twenty-fifth postirradiation days) or 1, 2, or 3 days prior to x-irradiation. Analysis of the data indicates that increased susceptibility to infection via the oral route following irradiation is dependent upon early damage to the gastrointestinal tract in conjunction with the depression of cellular and humoral defenses which develop at later postirradiation times.