Survival of Listeria monocytogenes in experimentally infected mice.

Physiological saline was found to be very detrimental to the viability of Listeria monocytogenes. The LD(50) value was substantially reduced when peptone was used as the suspending fluid rather than saline. Normal splenic tissue was not inhibitory to the survival of Listeria. In experimentally infected mice, L. monocytogenes survived for 8 days in the peritoneal cavity and for at least 11 days in the spleen.