Bacterial biofilms on cochlear implants – visualization of an altered morphology after the application of bioactive glass (BAG)

Introduction Bacterial biofilm formation on medical devices, such as cochlear implants (CI), can lead to chronic infections. Interestingly, bioactive glass (BAG) of type S53P4 seems to be a promising tool for use in the reduction of biofilm development. The aim of this investigation was to visualize changes in biofilm morphology via scanning electron microscopy (SEM) before and after the application of bioactive glass.

Methods Primarily, four bacterial species known to cause implant-related infections, P. aeruginosa (ATCC9027), S. aureus (ATCC6538), Staphylococcus epidermidis (ATCC12228) and Streptococcus pyogenes (ATCC19615) were analyzed regarding their capacity to form biofilm on CI components manufactured from three kinds of material: silicone, platinum and titanium. Subsequently, P. aeruginosa and S. aureus biofilms were visualized using scanning electron microscopy, comparing BAG-treated biofilm with non-treated biofilm.

Results The four bacterial species presented biofilm-forming capabilities in a species and surface dependent manner. S. aureus and P. aeruginosa showed the highest rate of biofilm formation on polystyrene surfaces. For both species, SEM revealed altered biofilm morphology after treatment of S53P4 BAG.

Conclusion This study indicates that bacterial biofilm formation and structure on CI components is dependent on the surface composition. After application of BAG, changes in biofilm morphology on CI components were observed. These data highlight the impact of BAG on bacterial biofilm morphology.

Publication History

Article published online:
10 June 2020