title: Ototoxicity resulting from intracochlear perfusion of Streptococcus pneumoniae in the guinea pig is modified by cefotaxime or amoxycillin pretreatment.
abstract: Acute changes in the electrophysiology and ultrastructure of the organ of Corti were studied after microperfusion of c. 5 x 10(6) CFU of serotype 2 Streptococcus pneumoniae D39 or Escherichia coli K-12 directly into the scala tympani of guinea pigs. Hearing loss was assessed by recording the auditory nerve compound action potential response to a 10 kHz tone pip. Mean hearing loss 3 h after pneumococcal perfusion (n = 4) was 44 dB, compared to 6 dB after E. coli perfusion (n = 4) (P<0.001). After pneumococcal perfusion, scanning electron microscopy revealed damage to hair cell stereocilia and cratering of the apical surface of supporting cells. Intraperitoneal injection of 100 mg/kg cefotaxime (n = 4) or 100 mg/kg amoxycillin (n = 4) 30 min before perfusion of pneumococci significantly reduced mean hearing loss to 23 dB (P=0.01) or 20 dB (P=0.01), respectively, and diminished ultrastructural damage. The data suggest that if pneumococci invade the inner ear during meningitis, cochlear deafness may rapidly ensue.
authors.affiliation: Department of Infection, University of Birmingham, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Winter
authors.forename: S D
authors.initials: SD
authors.lastname: Comis
authors.forename: M P
authors.initials: MP
authors.lastname: Osborne
authors.forename: T L
authors.initials: TL
authors.lastname: Hayward
authors.forename: J
authors.initials: J
authors.lastname: Stephen
authors.forename: M J
authors.initials: MJ
authors.lastname: Tarlow
mesh_terms: D000658:Amoxicillin / Q000627:therapeutic use*; D000818:Animals; D019072:Antibiotic Prophylaxis; D002439:Cefotaxime / Q000627:therapeutic use*; D002511:Cephalosporins / Q000627:therapeutic use*; D004427:Ear Diseases / Q000150:complications / Q000473:pathology / Q000517:prevention & control; D004594:Electrophysiology; D004926:Escherichia coli / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000188:drug therapy; D006168:Guinea Pigs; D006198:Hair Cells, Auditory / Q000473:pathology / Q000648:ultrastructure; D006313:Hearing Loss, Central / Q000382:microbiology; D008855:Microscopy, Electron, Scanning; D010406:Penicillins / Q000627:therapeutic use*; D011008:Pneumococcal Infections / Q000188:drug therapy* / Q000517:prevention & control; D012533:Scala Tympani / Q000382:microbiology*; D013296:Streptococcus pneumoniae / Q000472:pathogenicity*
chemical_list: D002511:Cephalosporins; D010406:Penicillins; D000658:Amoxicillin; D002439:Cefotaxime