title: Meningitis and a safe dexamethasone-eluting intracochlear electrode array.
abstract: OBJECTIVE
  To evaluate the potential risk of pneumococcal meningitis associated with the use of a dexamethasone-eluting intracochlear electrode array as compared with a control array.
  
  
  METHODS
  In two phases, adult Hooded-Wistar rats were implanted via the middle ear with an intracochlear array and were inoculated with Streptococcus pneumoniae 5 days post-surgery. Phase I created a dosing curve by implanting five groups (n = 6) with a control array, then inoculating 5 days later with different numbers of S. pneumoniae: 0 CFU, 10(3) CFU, 10(4) CFU, 10(4) CFU repeated, or 10(5) CFU (colony forming units). A target infection rate of 20% was aimed for and 10(4) CFU was the closest to this target with 33% infection rate. In phase II, we implanted two groups (n = 10), one with a dexamethasone-eluting array, the other a control array, and both groups were inoculated with 10(4) CFU of S. pneumoniae 5 days post-surgery.
  
  
  RESULTS
  The dexamethasone-eluting array group had a 40% infection rate; the control array group had a 60% infection rate. This difference was not statistically significant with a P value of ≥0.5.
  
  
  CONCLUSIONS
  The use of a dexamethasone-eluting intracochlear electrode array did not increase the risk of meningitis in rats when inoculated with S. pneumoniae via the middle ear 5 days following implantation.
authors.forename: Dimitra
authors.initials: D
authors.lastname: Stathopoulos
authors.forename: Scott
authors.initials: S
authors.lastname: Chambers
authors.forename: Louise
authors.initials: L
authors.lastname: Adams
authors.forename: Roy
authors.initials: R
authors.lastname: Robins-Browne
authors.forename: Christopher
authors.initials: C
authors.lastname: Miller
authors.forename: Ya Lang
authors.initials: YL
authors.lastname: Enke
authors.forename: Benjamin P C
authors.initials: BP
authors.lastname: Wei
authors.forename: Stephen
authors.initials: S
authors.lastname: O'Leary
authors.forename: Robert
authors.initials: R
authors.lastname: Cowan
authors.forename: Carrie
authors.initials: C
authors.lastname: Newbold
mesh_terms: D000818:Animals; D019929:Cochlear Implantation / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D003054:Cochlear Implants / Q000009:adverse effects*; D003907:Dexamethasone / Q000627:therapeutic use*; D005938:Glucocorticoids / Q000627:therapeutic use*; D008297:Male; D008586:Meningitis, Pneumococcal / Q000453:epidemiology* / Q000209:etiology; D016459:Prosthesis-Related Infections / Q000453:epidemiology* / Q000209:etiology; D051381:Rats; D017208:Rats, Wistar; D013296:Streptococcus pneumoniae
chemical_list: D005938:Glucocorticoids; D003907:Dexamethasone
keywords: Cochlear implant; Corticosteroid; Dexamethasone; Drug delivery; Meningitis; Rat; Streptococcus pneumoniae