title: Detection of bacterial biofilm on cochlear implants removed because of device failure, without evidence of infection.
abstract: OBJECTIVE
  To investigate the formation of bacterial biofilms on the surface of the electrode array of cochlear implants (CI) explanted because of device failure, without evidence of infection, by use of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM).
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Patients from 2 tertiary-care referral centers.
  
  
  METHODS
  CIs were explanted from 9 patients because of device failure. Specimens were immediately snap-frozen in cold isopenthane, stored at -80°C and examined with SEM and CLSM by 3 investigators.
  
  
  METHODS
  Presence of bacterial biofilm ascertained by SEM and CSLM.
  
  
  RESULTS
  One specimen showed the formation of a bacterial biofilm on the middle ear part of the electrode array. No biofilm formation was found in the inner-ear part of electrode arrays. In the middle-ear part of the electrode array, a cylindrical cover of human muscular tissue was seen plugging the cochleostomy.
  
  
  CONCLUSIONS
  This is the first study demonstrating that bacterial biofilms may exist on the surface of the electrode array of CIs explanted because of device failure but not infection. We found 1 case of biofilm formation in 9 explanted CIs. Further studies with larger series of CIs are required to investigate biofilm formation on the surface of CI electrode arrays to address both the pathophysiology of bacterial biofilms and prevention of device-related infections in CI patients.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Lariboisière Hospital, Assistance Publique des Hôpitaux de Paris & CNRS CESEM 8194, University Paris VII, Paris, France. katell.ruellan@lrb.aphp.fr
authors.forename: Katell
authors.initials: K
authors.lastname: Ruellan
authors.forename: Johan H M
authors.initials: JH
authors.lastname: Frijns
authors.forename: Guido V
authors.initials: GV
authors.lastname: Bloemberg
authors.forename: Charlotte
authors.initials: C
authors.lastname: Hautefort
authors.forename: Thierry
authors.initials: T
authors.lastname: Van den Abbeele
authors.forename: Gerda E M
authors.initials: GE
authors.lastname: Lamers
authors.forename: Philippe
authors.initials: P
authors.lastname: Herman
authors.forename: Patrice Tran Ba
authors.initials: PT
authors.lastname: Huy
authors.forename: Romain E
authors.initials: RE
authors.lastname: Kania
mesh_terms: D000328:Adult; D000368:Aged; D018441:Biofilms; D002648:Child; D002675:Child, Preschool; D003054:Cochlear Implants / Q000382:microbiology*; D004868:Equipment Failure; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D011446:Prospective Studies; D016459:Prosthesis-Related Infections / Q000382:microbiology*