Evaluation of hepatic disease in mice following intradermal inoculation with Corynebacterium pseudotuberculosis.
OBJECTIVE
To evaluate clinical, microbiologic, and pathologic outcomes in mice after inoculation with 4 equine-origin Corynebacterium pseudotuberculosis strains.


METHODS
15 C3H/HeJ mice.


METHODS
In a preliminary study, the optimum route of inoculation was determined. In the main study, mice were allocated to 4 treatment groups (3 mice/group). One slow- or rapid-growing equine-origin C pseudotuberculosis strain was inoculated ID into the mice of each treatment group.


RESULTS
All 4 strains had distinct tropism for the liver. Histologic lesions associated with rapid-growing strains included focally extensive unencapsulated areas of acute, massive coagulative necrosis of hepatocytes with intralesional colonies of bacteria and variable portal hepatitis characterized by accumulations of mononuclear and polymorphonuclear inflammatory cells. In contrast, the livers of mice inoculated with slow-growing strains had multiple discrete, randomly distributed foci of hepatocellular necrosis and neutrophilic hepatitis that were considerably less severe than the lesions in the mice inoculated with the rapid-growing strains. Significantly more bacterial colonies were recovered from the organs of mice inoculated with rapid-growing than with slow-growing strains of bacteria. Bacteria were isolated from the liver, spleen, lungs, and mesenteric lymph nodes of mice inoculated with rapid-growing strains and from the liver and lymph nodes of mice inoculated with slow-growing strains.


CONCLUSIONS
Study of host-bacteria interactions in hosts that are naturally infected with C pseudotuberculosis is difficult because of underlying genetic variability among animals, expense, and requirements for multiple replicates and control animals. The C3H/HeJ mice may provide a useful means for studying virulence mechanisms of C pseudotuberculosis.
Nieto
Nathan C
NC
Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Foley
Janet E
JE
MacLachlan
N James
NJ
Yuan
Tom
T
Spier
Sharon J
SJ
D000818:Animals; D003354:Corynebacterium Infections / Q000150:complications*; D016925:Corynebacterium pseudotuberculosis; D008099:Liver / Q000382:microbiology / Q000473:pathology*; D008107:Liver Diseases / Q000209:etiology* / Q000473:pathology*; D051379:Mice; D008817:Mice, Mutant Strains; D009336:Necrosis