Introduction The formation of bacterial biofilm on cochlear implants can lead to refractory
infections. Little is known about its specific morphology on cochlear implants. In
this study, bacterial biofilm on both implant and speech processor was quantified
and visualized by scanning electron microscopy.
Materials and Methods Four primary bacterial strains were tested on implant and speech
processor components from three manufacturers: Pseudomonas aeruginosa (ATCC9027),
Staphylococcus aureus (ATCC6538), Staphylococcus epidermidis (ATCC12228), and Streptococcus
pyogenes (ATCC19615). Biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa
(ATCC9027) was secondarily visualized by scanning electron microscopy.
Results The highest biofilm formation was observed with S. aureus and P. aeruginosa.
Higher biofilm formation was seen on the components of the implant compared to the
speech processor. The specific morphology of the bacterial cell surface as well as
the extracellular matrix could be visualized by scanning electron microscopy.
Discussion: The present study could demonstrate that the surface characteristics of
cochlear implants favor the formation of bacterial biofilm, which can be visualized
by scanning electron microscopy. The implant seems to be more susceptible to biofilm
formation than the speech processor.
