Clindamycin in a murine model of toxoplasmic encephalitis.

We investigated the efficacy of clindamycin in a murine model of toxoplasmic encephalitis using direct intracerebral inoculation. Clindamycin reduced mortality from 40% in normal mice and 100% in cortisone-treated mice to 0% in both groups. Although we were unable to document appreciable levels of clindamycin in the brains of infected mice, the histological features of cerebral infection were markedly altered. The formation of large numbers of cysts and the intense inflammatory response seen in the brains of normal mice and the unchecked infection and tissue necrosis in the brains of cortisone-treated mice were absent in the brains of clindamycin-treated mice. Enumeration of cysts in the brains of mice 10 weeks after infection revealed a significantly lower number in the clindamycin-treated mice. Spread of infection to other organs was also decreased during clindamycin administration. These observations suggest that clindamycin may have a role in the therapy of toxoplasmic encephalitis.