Silver-Containing Hydroxyapatite Coating Reduces Biofilm Formation by Methicillin-ResistantStaphylococcus aureusIn Vitro and In Vivo

Abstract

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.

Antibacterial Activity of Ag‐Hydroxyapatite Coating Against Hematogenous Infection by Methicillin‐ResistantStaphylococcus aureusin the Rat Femur

“…The MRSA strain used in this study, UOEH6 (University of Occupational and Environmental Health Hospital, Fukuoka, Japan), had been isolated from a blood sample of a septic patient. Bacteria were incubated overnight in trypticase soy broth (Eiken Chemical, Tokyo, Japan) at 37°C.…”

“…We previously developed a novel coating technology for the production of Ag‐containing hydroxyapatite (Ag‐HA) based on thermal spraying . Ag‐HA has been shown to release silver ions and possess antibacterial activity as well as inhibit adhesion and growth of methicillin‐resistant Staphylococcus aureus (MRSA) on the surface of implant materials both in vitro and in vivo. In addition, Ag‐HA coating shows good biocompatibility, good osteoconductivity, and low toxicity in vitro and in vivo.…”

Biofilms in Periprosthetic Joint Infections: A Review of Diagnostic Modalities, Current Treatments, and Future Directions

“…Silver oxide particles have been shown to inhibit biofilm formation on catheters 110 and titanium implants in a rabbit model, 111 while in vivo and in vitro data on silver oxide particles demonstrated reduced MRSA biofilm formation. 112 Silver oxide containing hydroxyapatite coated implants are currently being investigated as a coating for total hip arthroplasty implants, although this study is still in the pilot stage. 113 Iodine-coated titanium implants had significantly lower bacteria attachment compared with noniodine coated implants, and no viable bacteria were found on iodine-coated implants, including biofilm-forming bacteria MRSA, P. aeruginosa, and S. epidermidis.…”

Synthesis and Properties of Zinc-Modified Hydroxyapatite

“…The vast majority of studies [20,22,23,[26][27][28] of zinc-substituted HA indicate zinc content in the concentration range 0.1-4%. The best results in terms of biocompatibility, osteoconductivity and antimicrobial activity are achieved at a Zn 2+ content of 1-2% [20,21,24]. It is noteworthy that in vivo tests on model animals showed the ability of ZnHA to accelerate the formation of new bone compared with pure HA during implantation in rats [29] and rabbits [30] for one and two months, respectively.…”

“…HA doped with zinc has been confirmed as an effective antimicrobial agent against gram-positive and gram-negative bacteria that are often found at the implantation site: for example, S. aureus, Streptococcus mutans, Staphylococcus epidermidis, Enterobacter aerogenes, E. coli [2,[20][21][22][23][24][25]. The release of Zn 2+ ions acted against fungal infection, and after 72 h the C. albicans biofilm decreased significantly, with a zinc content of 3% [26].…”