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


METHODS
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.


RESULTS
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.


CONCLUSIONS
Hearing loss resulting from canal injury in the presence of Pseudomonas OM may be mediated by exotoxin A.


CONCLUSIONS
Treatment to neutralize the effects of exotoxin A may minimize the risk of hearing loss with canal fistula in chronic OM.
Yunus
Tariq M
TM
Department of Otolaryngology,University of Florida, Gainseville, FL 32610-0264, USA.
Molina
Rolando M
RM
Prevatt
Angela R
AR
Gajewski
Byron J
BJ
Sedwick
Jack D
JD
Antonelli
Patrick J
PJ
D036002:ADP Ribose Transferases / Q000502:physiology*; D000818:Animals; D001427:Bacterial Toxins; D005098:Exotoxins / Q000502:physiology*; D005260:Female; D005402:Fistula / Q000150:complications*; D006168:Guinea Pigs; D006319:Hearing Loss, Sensorineural / Q000150:complications / Q000382:microbiology* / Q000503:physiopathology*; D007759:Labyrinth Diseases / Q000150:complications*; D008297:Male; D010033:Otitis Media / Q000150:complications / Q000382:microbiology* / Q000503:physiopathology; D012665:Semicircular Canals; D037521:Virulence Factors / Q000502:physiology*; D000097668:Pseudomonas aeruginosa Exotoxin A
D036002:ADP Ribose Transferases; D001427:Bacterial Toxins; D005098:Exotoxins; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A