Comparison of Otitis Media Due to Types 3 and 23 Streptococcus pneumoniae in the Chinchilla Model

Only a few pneumococcal serotypes are responsible for the majority of cases of acute otitis media due to Streptococcus pneumoniae in children. The immunopathogenesis of otitis media cause by two serotypes, type 3 and 23, was studied in chinchillas. Chinchillas with type 23 pneumococcal otitis media were capable of clearing the infection over a six-week period without treatment, whereas the type 3 infection persisted throughout the six-week study. In addition, bacteremia or meningitis occurred more frequently and earlier with type 3 pneumococcal otitis media than with type 23. The resolution of the type 23 pneumococcal infection paralleled the development of type-specific antibody, as measured by radioimmunoassay, whereas type 3 infection was associated with a fall in serum antibody to low levels. Since the pathogenesis of pneumococcal otitis media in the chinchilla differs between pneumococcal serotypes, it may be important to correlate pneumococcal serotypes with sequealae and recurrence of otitis media in children.