title: Auditory function after application of ototopical vancomycin and mupirocin solutions in a murine model.
abstract: OBJECTIVE
  To determine whether mupirocin (440 µg/mL) and vancomycin otic drops (25 mg/mL) show evidence of ototoxicity in CBA/J mice immediately following a 7-day course of daily intratympanic (IT) injections and 1 month following treatment.
  
  
  METHODS
  Nonrandomized controlled trial.
  
  
  METHODS
  Academic hospital laboratory.
  
  
  METHODS
  Twenty CBA/J mice.
  
  
  RESULTS
  Mean auditory brainstem response (ABR) thresholds increased in all drug- and saline-treated ears immediately after 7 days of IT injections but returned to baseline for most stimulus frequencies by 30 days later. This finding appeared to be correlated with the presence and subsequent resolution of tympanic membrane (TM) perforations and granulation tissue at the injection sites. Mupirocin-treated ears showed no significant difference in ABR thresholds compared to saline-treated ears. No significant differences were noted between vancomycin- and saline-treated ears, but there was a significant interaction between testing day and stimulus frequency (P < .001). Further analysis revealed that ABR thresholds at 32 kHz remained significantly elevated in vancomycin-treated mice despite the resolution of TM perforations and granulation tissue 30 days after completion of IT injections (95% confidence interval, -13.5 to -5.5, P < .01).
  
  
  CONCLUSIONS
  Although IT application of mupirocin solution (440 µg/mL) caused no significant change in the ABR thresholds in a murine model, vancomycin solution (25 mg/mL) resulted in high-frequency threshold elevations in both the ear directly injected and the contralateral ear. Mupirocin solution may be beneficial in managing otitis externa and media caused by resistant pathogens. Further studies of ototopical vancomycin are needed to define parameters governing its safe use.
authors.affiliation: University of Connecticut Health Center, Division of Otolaryngology-Head & Neck Surgery, Farmington, Connecticut 06030, USA. krutherford@resident.uchc.edu
authors.forename: Kimberley D
authors.initials: KD
authors.lastname: Rutherford
authors.forename: Katherine
authors.initials: K
authors.lastname: Kavanagh
authors.forename: Kourosh
authors.initials: K
authors.lastname: Parham
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects*; D005260:Female; D006097:Granulation Tissue; D015552:Injections, Intralesional; D051379:Mice; D008808:Mice, Inbred CBA; D016712:Mupirocin / Q000008:administration & dosage*; D010033:Otitis Media / Q000188:drug therapy; D014640:Vancomycin / Q000008:administration & dosage*
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin; D016712:Mupirocin