Objective: To create an experimental model of Streptococcus pneumoniae type 3 meningogenic labyrinthitis (a leading cause of deafness) similar to that in human disease. Design: Cohort analytic study of guinea pigs that were inoculated intrathecally with varying dilutions of S pneumoniae type 3; the progress of the disease was compared with that in saline solution-inoculated control animals. Subjects: Healthy adult Hartley guinea pigs without clinical evidence of middle ear disease that were conveniently sampled. Interventions: Intrathecal inoculation of 104 to 106 colony-forming units of S pneumoniae type 3 into 13 guinea pigs; signs and symptoms of meningitis/labyrinthitis were observed for 15 days and compared with those in two saline solution- inoculated control animals. Main Outcome Measures: Morbidity-labyrinthitis, meningitis; end point-death. Results: The 104 to 106 colony-forming units of S pneumoniae type 3 caused inflammation that extended from the meninges to the inner ear via the cochlear aqueduct within 3 days after inoculation; a dose of 107 killed animals within 12 hours after inoculation. Three of five animals that were inoculated with a 106 dose died 3 days after inoculation; two of three animals that were inoculated with a 105 dose lived to 15 days after inoculation. One of two animals that were inoculated with a 104 dose did not become infected. Inflammation extended to the middle ear by round- window destruction. Reactive bone formation simulated labyrinthine osteosclerosis. Observers assessed histologic slides 'blindly.' Conclusion: Guinea pigs can survive 15 days after intrathecal inoculation of a 105 dose, with morphologic features similar to those in human disease. This is an effective model for this study of meningogenic labyrinthitis.
|Original language||English (US)|
|Number of pages||5|
|Journal||Archives of Otolaryngology--Head and Neck Surgery|
|State||Published - Dec 1994|
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