Interaction between Salmonella enteritidis and Candida albicans

Abstract

Summary

Injection of Candida albicans ic facilitated establishment of disease as evidenced from the LD₅₀ studies. The LD₅₀ at 14 days for mice injected ic with C. albicans was log 5.2 ± 0.5 cells and log 7.2 ± 0.5 cells when injected ip. The LD₅₀ at 14 days for Salmonella enteritidis injected ic was log 6.6 ± 0.5. Interaction between mixed cultures of C. albicans and S. enteritidis was studied under various environmental conditions. Retardation of growth of C. albicans was noted in broth in presence of actively growing S. enteritidis. Cell-free culture filtrates of S. enteritidis or of C. albicans failed to inhibit proliferating cells of competing organisms. Also, test cultures grew commensally on all plates incubated aerobically as well as under anaerobic or microaerophilic conditions.

Proliferation of S. enteritidis in the spleen, ceca, kidneys, and liver depended upon number of cells injected. Several organ tissues showed the presence of large populations of S. enteritidis when infected ip with log 6.0 or more S. enteritidis cells. No deaths occurred among animals receiving log 5.0 S. enteritidis cells. The spleen and blood of mice infected with C. albicans were able to eliminate the organisms rapidly. When mice received only C. albicans (log 5.0 cells), large populations of the organism were noted in both kidney and cecum. Lower concentrations of C. albicans were readily eliminated by these organs. Mice infected with S. enteritidis 24 hr prior to infection with C. albicans exhibited three conditions depending upon the numbers of cells of S. enteritidis. High numbers (above log 7.0) of S. enteritidis cells produced greater mortality rates in infected animals similar to those where no C. albicans were injected. Log 6.0 S. enteritidis cells plus log 5.0 C. albicans cells (lethal dosages) prevented mortality to mice. Lower numbers of S. enteritidis (log 5.0 or less) did not produce disease syndrome in mice and did not alter lethal effect of C. albicans. Organ tissues of mice preinfected with log 6.0 S. enteritidis and then injected with log 5.0 C. albicans cells showed a decrease in growth of C. albicans. The cecum of these mice did not support growth of Candida. Evidence indicated that interaction between these test cultures prevented invasion of the tissues by C. albicans.