Influence of long-term cadmium and selenite exposure on resistance to Listeria monocytogenes during acute and chronic infection in mice

Abstract

The aim of the present study was to evaluate the effect of long-term exposure to cadmium and selenite ions on the BALB/c mice resistance to experimental Listeria monocytogenes infection. A low-dose six-week exposure to cadmium ions (10 mg/l in drinking water) decreased the clearance of listeria from mice liver and spleen at 24 h in the early phase of infection. Long-term treatment of mouse with selenite ions (0.15 mg/l) did not activate the elimination of bacteria from the organs. Eight weeks of poisoning with high doses (100 mg/l) of cadmium during chronic infection affected the growth rate and survival of mice while selenite ions increased tiese parameters. Long-term Cd2+ and SeO3 2- exposure increased (p < 0.05) the number of bacteria carriers in all the experimental groups of mice. Higher doses of Cd2+ increased listeria persistence in liver as compared to lower Cd2+ doses, but the difference was not significant. The titer of anti-listerial antibodies in blood serum in the group treated with SeO3 2- was lower (p < 0.05) than in the control group, but higher than in the mice intoxicated with Cd2+. In conclusion, mice intoxicated with high doses of cadmium were more susceptible to L. monocytogenes infection than non-intoxicated mice or intoxicated with a small concentration of cadmium ions. Selenite ions did not reduce the negative effect of cadmium on the resistance of mice to bacterial infection, although increased the production of antibodies to L. monocytogenes. Keywords: cadmium, selenite, experimental mice, infection, Listeria monocytogenes