Related Experiment Videos
A rat model for bacterial otitis media
A Hermansson1, P Emgård, K Prellner
1Department of Oto-rhino-laryngology, University of Lund, Sweden.
Abstract:
Rat middle ear was exposed to challenge with viable pneumococci, type 3 and 6A, and the course of changes in the middle ear was observed by otomicroscopy and analysis of bacterial samples from blood, nasopharynx and middle ear effusions. Microscopical examination of changes in the middle ear mucosa during and after the acute infection was also made. Depending on the type and concentration of pneumococci, three different results were observed: otitis media with purulent effusion, otitis media with serous effusion, or no reaction at all. The mortality rate was low and most animals recovered within 10 days without postinfectional changes visible by otomicroscopy. The microscopical examination of the middle ear mucosa revealed distinct changes. Inoculation of rat middle ear with pneumococci causes a self-limiting infection that closely resembles acute otitis media in the human. Thus the rat would seem to be a suitable animal model for the study of bacterial otitis media.
Insights
This study shows that inoculating rat middle ears with pneumococci creates a self-limiting infection, similar to human acute otitis media. Rats are a suitable animal model for studying bacterial otitis media.
Area of Science:
- Otolaryngology
- Microbiology
- Animal Models
Background:
- Bacterial otitis media is a common infection.
- Understanding its pathogenesis requires suitable animal models.
Purpose of the Study:
- To evaluate the rat middle ear as a model for bacterial otitis media.
- To observe the effects of pneumococcal challenge on the rat middle ear.
Main Methods:
- Rats' middle ears were challenged with viable Streptococcus pneumoniae (types 3 and 6A).
- Otomicroscopy and bacterial sample analysis (blood, nasopharynx, middle ear effusions) were performed.
- Microscopical examination of middle ear mucosa changes was conducted.
Main Results:
- Infection outcomes varied (purulent effusion, serous effusion, no reaction) based on pneumococcal type and concentration.
- Low mortality and rapid recovery (within 10 days) were observed.
- Distinct microscopic changes in the middle ear mucosa were evident despite otomicroscopic recovery.
Conclusions:
- Pneumococcal inoculation in the rat middle ear induces a self-limiting infection.
- The observed infection closely mimics human acute otitis media.
- The rat serves as a suitable animal model for studying bacterial otitis media.