Nonhuman primate model for the study of respiratory Klebsiella pneumoniae infection.

Squirrel monkeys were inoculated by the intratracheal inoculation of 700 Klebsiella pneumoniae organisms and developed lobar pneumonia in about 24 h. Characteristic clinical findings were fever, anorexia, and coughing. Laboratory findings included leukocytosis or leukopenia (with the latter more prominent in ultimately fatal infections), bacteremia, and shedding of bacteria into the pharynx. Infected monkeys showed increased plasma lysozyme activity as well as increased plasma ceruloplasmin, haptoglobin and alpha1-antitrypsin. The mortality rate was 60%, and the mean time of death was 50.5 h. Pathologically, the disease spread by means of Kohn's pores and other pathways that generally did not involve airways as a means of dissemination until about 30 h. Squirrel monkeys seem to be better models for human respiratory K. pneumoniae infection than rats or mice.