title: Hematogenous pneumococcal meningitis in the infant rat: description of a model.
abstract: Sensorineural deafness occurs in 20%-30% of children after Streptococcus pneumoniae meningitis. An infant rat model of S. pneumoniae meningitis was developed to study the pathogenesis of inner ear invasion by S. pneumoniae. S. pneumoniae type 6 was administered intraperitoneally (inoculum: 1-10 x 10(8) cfu) every 24 h for 3 days to 5-day-old rats. Bacteremia (12 [50%] of 24) and meningitis (11 [46%] of 24) were detected most frequently 4 days after the three doses. The mean cerebrospinal fluid (CSF) white blood count for rats with positive CSF cultures was 7271/mm3 (range, 81-20,475). Hematoxylin-eosin-stained brain tissue from the 11 rats with positive CSF cultures showed inflammation in the meninges and scala tympani in 9 each (82%), and scala vestibuli in 6 (55%), but none in the scala media. Gram's-stained brain and inner ear sections from the same 11 rats showed organisms in the meninges in 5 (45%) and scala tympani or vestibuli in 2 (18%). Perilymphatic inflammation occurred significantly (P less than .001) more than did endolymphatic inflammation.
authors.affiliation: Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030.
authors.forename: A F
authors.initials: AF
authors.lastname: Rodriguez
authors.forename: S L
authors.initials: SL
authors.lastname: Kaplan
authors.forename: E P
authors.initials: EP
authors.lastname: Hawkins
authors.forename: E O
authors.initials: EO
authors.lastname: Mason
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D016470:Bacteremia / Q000150:complications; D003638:Deafness / Q000209:etiology*; D004195:Disease Models, Animal; D007762:Labyrinthitis / Q000209:etiology*; D008586:Meningitis, Pneumococcal / Q000150:complications*; D051381:Rats; D013047:Specific Pathogen-Free Organisms