Acute Streptococcus pneumoniae meningogenic labyrinthitis. An experimental guinea pig model and literature review.
OBJECTIVE
To create an experimental model of Streptococcus pneumoniae type 3 meningogenic labyrinthitis (a leading cause of deafness) similar to that in human disease.


METHODS
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.


METHODS
Healthy adult Hartley guinea pigs without clinical evidence of middle ear disease that were conveniently sampled.


METHODS
Intrathecal inoculation of 10(4) to 10(6) 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.


METHODS
Morbidity--labyrinthitis, meningitis; end point--death.


RESULTS
The 10(4) to 10(6) 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 10(7) killed animals within 12 hours after inoculation. Three of five animals that were inoculated with a 10(6) dose died 3 days after inoculation; two of three animals that were inoculated with a 10(5) dose lived to 15 days after inoculation. One of two animals that were inoculated with a 10(4) 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."


CONCLUSIONS
Guinea pigs can survive 15 days after intrathecal inoculation of a 10(5) dose, with morphologic features similar to those in human disease. This is an effective model for this study of meningogenic labyrinthitis.
Blank
A L
AL
Department of Otolaryngology, Albert Einstein College of Medicine, Bronx, NY.
Davis
G L
GL
VanDeWater
T R
TR
Ruben
R J
RJ
D000208:Acute Disease; D000818:Animals; D003638:Deafness / Q000209:etiology; D004195:Disease Models, Animal; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D007762:Labyrinthitis / Q000150:complications / Q000382:microbiology / Q000401:mortality / Q000473:pathology; D007928:Lethal Dose 50; D008297:Male; D015588:Observer Variation; D010026:Osteosclerosis / Q000209:etiology; D011008:Pneumococcal Infections / Q000150:complications / Q000382:microbiology / Q000401:mortality / Q000473:pathology; D012720:Severity of Illness Index; D015996:Survival Rate