HEMATOGENOUS BACTERIAL-MENINGITIS IN AN INTERCELLULAR-ADHESION MOLECULE-1-DEFICIENT INFANT MOUSE MODEL

Mice genetically deficient in the gene encoding for intercellular adhe sion molecule-1 (ICAM-1) production were compared with wild-type mice after injection with Haemophilus influenzae type b (Hib) or Streptococ cus pneumoniae. The incidence of Hib bacteremia was greater in the ICA M-1-deficient mice than wild-type mice (P = .007), but mortality was g reater for wild-type mice at 24 h (P = .03). In contrast, the incidenc e of S. pneumoniae bacteremia was equivalent but mortality was greater in ICAM-1-deficient mice at 24 h (P = .0003), More ICAM-1-deficient m ice had cerebrospinal fluid cultures (CSF) positive for Hib (P = .04), whereas all animals at sacrifice had CSF cultures positive for S. pne umoniae, CSF white blood cell counts and histology of the meninges and cochlea were no different between groups for either organism. ICAM-1 deficiency may be protective early in Hib infection but has a detrimen tal effect in S. pneumoniae infection.