Haemophilus influenzae meningitis in infant rats: role of bacteremia in pathogenesis of age-dependent inflammatory responses in cerebrospinal fluid.

Abnormalities in cerebrospinal fluid associated with meningitis due to Haemophilus influenzae type b were characterized in infant rats. After intranasal inoculation of bacteria, the development of intense bacteremia (greater than 10(4) colony-forming units/ml) correlated with cultures of cerebrospinal fluid positive for H. influenzae, with pleocytosis, and with hisotologic evidence of meningitis. The degree of pleocytosis was related to the age of the animal, the amount of time since inoculation, and the severity of the meningitis.