ABSTRACT
BACKGROUND: Cochlear implant (CI) drug delivery (DD) may improve electrophysiological outcomes, but it may also increase the risk of suppurative complications. The aim of this study was to evaluate the development of bacterial biofilms on DD ports when subjected to varying types of penetration. METHODS: Silastic models were constructed to represent CIs with a DD channel, with an intact port, a widely opened port, a noncoring needle penetrating the port, and a noncoring needle removed from the port. CIs were exposed to a culture of a biofilm-forming strain of Staphylococcus aureus for 5 days. Biofilm formation was assessed with quantitative bacterial counts (after eliminating planktonic bacteria) and scanning electron microscopy. RESULTS: Bacterial counts were significantly higher in CIs with widely fenestrated ports than all other port conditions (P = 0.0003). CONCLUSIONS: Biofilm formation may be minimized on CIs with DD by using fine, noncoring needles and limiting the duration of port penetration.
Subject(s)
Anti-Bacterial Agents/administration & dosage , Biofilms , Cochlear Implants , Drug Delivery Systems , Staphylococcus aureus/physiology , Drug Delivery Systems/instrumentation , Equipment Design , Microscopy, Electron, Scanning , Models, Anatomic , NeedlesABSTRACT
BACKGROUND: Cochlear implant (CI) recesses, such as the removable magnet pocket, appear to harbor more biofilm than smooth surfaces. The aim of this study was to examine the impact of removable magnets on biofilm formation in an in vitro model. METHODS: Silastic models were constructed to represent CIs with and without a magnet pocket and with and without a titanium blank in the pocket. CIs were exposed to a culture of a biofilm forming strain of Staphylococcus aureus. Adherence of planktonic bacteria and biofilm formation were assessed with quantitative bacterial counts and scanning electron microscopy. RESULTS: Adherent bacterial counts were significantly higher in CI models with an empty magnet pocket (P = 0.0097). Biofilm formation was significantly lower in CI models without a magnet pocket (P = 0.0121). CONCLUSIONS: CI magnet pockets harbor bacteria that can increase biofilm development in an in vitro model.
