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Pseudomonas otitis media after eustachian tube obstruction
P J Antonelli1, S K Juhn, M V Goycoolea
1Otitis Media Research Center, University of Minnesota School of Medicine, Minneapolis.
Abstract:
Previous experiments have shown that Pseudomonas aeruginosa may infect the middle ears of chinchillas by way of the eustachian tube and that chinchillas with acute otitis media (AOM) are more susceptible to pseudomonas infection than animals without AOM. The purpose of this experiment was to examine the effects of otitis media with effusion (OME), induced by means of eustachian tube obstruction, on middle ear susceptibility to nasal inoculation of P. aeruginosa. Chinchilla eustachian tubes were obstructed with silicone rubber sponge bilaterally; OME developed in eight animals (11 ears)--three bilaterally and five unilaterally--and persisted for 6 months. Ten chinchillas with normal eustachian tube function served as controls. All animals were nasally inoculated with 5 x 10(6) colony-forming units of P. aeruginosa. Pseudomonas otitis media developed in eight of 11 OME ears with effusion, none of five ears without OME, and four of 20 control ears (chi 2 = 11.782, p = 0.003). Therefore, P. aeruginosa can infect the middle ear by way of the eustachian tube. Tubal dysfunction may lead to the development of chronic suppurative otitis media by increasing tubotympanic susceptibility to opportunistic pathogens.
Insights
Otitis media with effusion (OME) increases middle ear susceptibility to Pseudomonas aeruginosa infection. This suggests tubal dysfunction may contribute to chronic suppurative otitis media development.
Area of Science:
- Otolaryngology
- Microbiology
- Infectious Diseases
Background:
- Pseudomonas aeruginosa can infect the middle ear via the eustachian tube.
- Acute otitis media (AOM) increases susceptibility to Pseudomonas infection.
Purpose of the Study:
- To investigate the impact of otitis media with effusion (OME) on middle ear susceptibility to P. aeruginosa.
- To determine if eustachian tube obstruction influences Pseudomonas infection risk.
Main Methods:
- Chinchilla eustachian tubes were obstructed to induce OME.
- OME was confirmed in 8/11 animals and persisted for 6 months.
- Animals (OME and control) were nasally inoculated with P. aeruginosa.
Main Results:
- Pseudomonas otitis media developed in 8/11 OME ears versus 4/20 control ears (p=0.003).
- No infections occurred in OME ears without effusion.
- This confirms P. aeruginosa can infect the middle ear through the eustachian tube.
Conclusions:
- Eustachian tube dysfunction, leading to OME, increases middle ear susceptibility to P. aeruginosa.
- Tubal dysfunction may predispose to chronic suppurative otitis media by enhancing susceptibility to opportunistic pathogens.