Effect of cyclosporine A (CsA), cyclophosphamide (Cy) and azathioprine (Aza) on the survival of Listeria innocua in mice.

Immunosuppressors reducing the defensive mechanisms of the organism make favourable conditions for the development of different infections, particularly for intracellular facultative bacteria such as Listeria. In this paper, the effects of different doses of cyclosporine A (CsA), cyclophosphamide (Cy) and azathioprine (Aza) on the survival of Listeria innocua, a nonpathogenic strain, in the peritoneal cavity and spleen of BALB/c mice, were investigated. It was found that CsA and Aza, applied on total doses: 50-250 micrograms/g or 20-100 micrograms/g respectively, before or on the day of bacteria injection, prolong their longer survival as a result of reduced elimination. In CsA treated animals the number of survived Listeria is higher in the spleen while in Aza treated animals--in the peritoneal cavity. The Cy effect appeared to be the weakest because only the immunosuppressive (300 micrograms/g) dose was able to significantly enhance the survival of L. innocua both in the peritoneal cavity and the spleen. The results are a warning for clinicians applying the immunosuppressor treatment.