Hearing loss with semicircular canal fistula in exotoxin A-deficient Pseudomonas otitis media.

Yunus, Tariq M; Molina, Rolando M; Prevatt, Angela R; Gajewski, Byron J; Sedwick, Jack D; Antonelli, Patrick J · Otolaryngol Head Neck Surg · 2004

other · Level V

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Abstract

The study goal was to compare the severity of hearing loss with semicircular canal injury in the presence of otitis media (OM) due to an exotoxin A-producing strain of Pseudomonas aeruginosa (PA+) and an exotoxin A-deficient daughter strain (PA-). PA+ or PA- was injected bilaterally into guinea pig ears. Three days later, unilateral lateral semicircular canal transection was performed. Hearing was tested before and after transection. PA OM was induced in all injected ears. Significant elevation of click and 12-kHz thresholds (P < 0.0001) were encountered in PA+-infected ears. No significant threshold elevations were encountered in PA--infected ears. Hearing loss resulting from canal injury in the presence of Pseudomonas OM may be mediated by exotoxin A. Treatment to neutralize the effects of exotoxin A may minimize the risk of hearing loss with canal fistula in chronic OM.

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