Preventing Implant-Associated Infections by Silver Coating

Abstract

d Implant-associated infections (IAIs) are a dreaded complication mainly caused by biofilm-forming staphylococci. Implant surfaces preventing microbial colonization would be desirable. We examined the preventive effect of a silver-coated titanium-aluminum-niobium (TiAlNb) alloy. The surface elicited a strong, inoculum-dependent activity against Staphylococcus epidermidis and Staphylococcus aureus in an agar inhibition assay. Gamma sterilization and alcohol disinfection did not alter the effect. In a tissue cage mouse model, silver coating of TiAlNb cages prevented perioperative infections in an inoculum-dependent manner and led to a 100% prevention rate after challenge with 2 ؋ 10 6 CFU of S. epidermidis per cage. In S. aureus infections, silver coating had only limited effect. Similarly, daptomycin or vancomycin prophylaxis alone did not prevent S. aureus infections. However, silver coating combined with daptomycin or vancomycin prophylaxis thwarted methicillin-resistant S. aureus infections at a prevention rate of 100% or 33%, respectively. Moreover, silver release from the surface was independent of infection and occurred rapidly after implantation. On day 2, a peak of 82 g Ag/ml was reached in the cage fluid, corresponding to almost 6؋ the MIC of the staphylococci. Cytotoxicity toward leukocytes in the cage was low and temporary. Surrounding tissue did not reveal histological signs of silver toxicity. In vitro, no emergence of silver resistance was observed in several clinical strains of staphylococci upon serial subinhibitory silver exposures. In conclusion, our data demonstrate that silver-coated TiAlNb is potent for prevention of IAIs and thus can be considered for clinical application.

Biomimetic antimicrobial cloak by graphene-oxide agar hydrogel

“…Substances exploited for coating include antibiotics 9 , silver 10 , titanium 11 , hydroxyapatite 12 , and the fluoride ion 13 . For a prolonged effect, the treatment must be repeated 14, 15 with severe cumulative toxic effects on patients 16 .…”

Options and Limitations in Clinical Investigation of Bacterial Biofilms

“…Rat models are in constant use due to their amenability to wound and infection site colonization without the requirement of disturbing factors (foreign bodies or diabetes mellitus induction), allowing a correlation with rat age, location of the wound, and size of the inoculum (348). Mouse models employing tissue cages and catheter infection can provide information about the antimicrobial efficacy of biomaterial coatings and host-pathogen interactions (349,350). In the field of implanted device-associated infections, a major model involves totally implantable venous access ports (TIVAPs) implanted in rats.…”

Fluorescence-tunable Ag-DNA biosensor with tailored cytotoxicity for live-cell applications

“…In the past years, silver has been increasingly used in cosmetics, clothes, implant coatings, and for burn wound dressings, to obtain an antibacterial effect17181920. Its inherent toxicity makes the metal a particularly promising alternative to antibiotics, as bacterial resistances rise2122, as well as an anti-cancer agent232425.…”