Imaging studies of bacterial biofilms on cochlear implants—Bioactive glass (BAG) inhibits mature biofilm

Abstract

The capability of Pseudomonas aeruginosa and Staphylococcus aureus to form biofilm on varying CI component materials differs in the presence and absence of bioactive glass (BAG). The application of BAG induces significant changes in biofilm morphology which can be visualized via scanning electron microscopy (SEM). Bacterial biofilm formation on medical devices, such as cochlear implants (CI), can lead to chronic infections. Interestingly, BAG of type S53P4 seems to be a promising tool for use in the reduction of biofilm development. 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. The four bacterial species presented biofilm-forming capabilities in a species and surface dependent manner. Metal CI components allowed for the greatest proliferation of biofilm. 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. This study indicates that bacterial biofilm formation and structure on CI components is dependent on the surface composition, altering between metal and silicone surfaces. After application of BAG, changes in biofilm morphology on CI components were observed. These data highlight the impact of BAG on bacterial biofilm morphology.

Biofilm-Forming Potential of Ocular Fluid Staphylococcus aureus and Staphylococcus epidermidis on Ex Vivo Human Corneas from Attachment to Dispersal Phase

“…However, temporal dynamics of the biofilm formation by ocular Staphylococcal spp. from attachment to dispersal phase were rarely monitored [ 53 , 54 , 58 ]. Hou et al [ 54 ] using SEM, observed that ocular biofilm-positive staphylococcal strains go through a phase of adhesion and accumulate as small monolayer sheets which then get transformed into multilayer sheets enclosed in the self-secreted EPS.…”

“…Staphylococcus aureus and S. epidermidis are also commonly found infecting the anophthalmic cavity of ocular prosthesis users [ 51 , 52 ]. Some or all the previous studies on biofilm formation in S. aureus and S. epidermidis used non-clinical strains [ 53 ], whereas, in this study, both S. aureus and S. epidermidis were of clinical origin, isolated from patients with infectious Endophthalmitis. Biofilm formation was monitored by Congo red (CR) method as in the previous studies [ 54 ]; but, for monitoring the temporal dynamics of biofilm formation, we used the Crystal violet (CV) method [ 54 ] and also the XTT method [ 55 ].…”

“…In this study, Confocal laser scanning microscopy (CLSM) was used to monitor the temporal changes in the thickness of the biofilm [ 56 , 57 ]. Additionally, scanning electron microscopy (SEM) was used to visualize the biofilm from attachment to dispersal phase as in a few earlier studies [ 53 , 54 , 58 ]. A unique feature of this study is that in addition to using cover slips, human donor corneas were also used as a substratum for monitoring biofilm formation.…”

Titanium Implants and Local Drug Delivery Systems Become Mutual Promoters in Orthopedic Clinics

“…The biofilm forms a microenvironment that supports the bacteria and protects them from host defense systems and antibacterial drugs. As the metabolic activity of biofilm-resident bacteria decreases, their sensitivity to most antimicrobial agents also decreases [ 36 ]. A structured layer of bacterial biofilm is shown in Figure 2 A [ 37 ].…”

Preventing Biofilm Formation and Development on Ear, Nose and Throat Medical Devices

“…Studies found patterns of biofilm formations for species and materials [111]. There are great examples of bioglass such as S53P4, which contains sodium oxide, phosphorus pentoxide, silicon dioxide, and calcium oxide and has been tested successfully for osteoinduction and reduction of bacteria [112,113].…”