Silver-Containing Hydroxyapatite Coating Reduces Biofilm Formation by Methicillin-Resistant Staphylococcus aureus In Vitro and In Vivo

Abstract EN

Biofilm-producing bacteria are the principal causes of infections associated with orthopaedic implants.

We previously reported that silver-containing hydroxyapatite (Ag-HA) coatings exhibit high antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA).

In the present study, we evaluated the effects of Ag-HA coating of implant surfaces on biofilm formation.

Titanium disks (14-mm diameter, 1-mm thickness), one surface of which was coated with HA or 0.5%–3.0% Ag-HA with a thermal spraying technique, were used.

In vitro, the disks were inoculated with an MRSA suspension containing 4×105 CFU and incubated for 1-2 weeks.

In vivo, MRSA-inoculated HA and 3% Ag-HA disks (8.8–10.0 × 108 CFU) were implanted subcutaneously on the back of rats for 1–7 days.

All disks were subsequently stained with a biofilm dye and observed under a fluorescence microscope, and biofilm coverage rates (BCRs) were calculated.

The BCRs on the Ag-HA coating were significantly lower than those on the HA coating at all time points in vitro (p<0.05).

Similar results were observed in vivo (p<0.001) without argyria.

Ag-HA coating reduced biofilm formation by MRSA in vitro and in vivo; therefore, Ag-HA coating might be effective for reducing implant-associated infections.