Antimicrobial Silver Multilayer Coating for Prevention of Bacterial Colonization of Orthopedic Implants

Abstract

Due to increasing rates of periprosthetic joint infections (PJI), new approaches are needed to minimize the infection risk. The first goal of this study was to modify a well-established infection model to test surface-active antimicrobial systems. The second goal was to evaluate the antimicrobial activity of a silver multilayer (SML) coating. In vitro tests with SML items showed a >4 Log reduction in a proliferation assay and a 2.2 Log reduction in an agar immersion test (7 d). In the in vivo model blank and SML coated K-wires were seeded with ~2 × 104 CFU of a methicillin-sensitive Staphylococcus epidermidis (MSSE) and inserted into the intramedullary tibial canal of rabbits. After 7 days, the animals were sacrificed and a clinical, microbiological and histological analysis was performed. Microbiology showed a 1.6 Log pathogen reduction on the surface of SML items (p = 0.022) and in loosely attached tissue (p = 0.012). In the SML group 7 of 12 SML items were completely free of pathogens (cure rate = 58%, p = 0.002), while only 1 of 12 blank items were free of pathogens (cure rate = 8%, p = 0.110). No silver was detected in the blood or urine of the SML treated animals and only scarcely in the liver or adjacent lymph nodes. In summary, an in vivo infection model to test implants with bacterial pre-incubation was established and the antimicrobial activity of the SML coating was successfully proven.

Interplay of phosphate and carbonate ions with flavin photosensitizers in photodynamic inactivation of bacteria

“…In principle, the applied method concerning cultivation and evaluation of the microbial reduction is a adaption of a method initially described by Bechert and co-workers [ 29 ] and has been successfully used for example by Bruenke et al . [ 30 ]. Doubling time was calculated for an optical density of 0.2 and 0.4.…”

“…20 μl of this reacting solution were transferred to 180 μl preheated Mueller-Hinton bouillon and cultivated at 37˚C for 48 h. A plate reader measured the optical density at 600 nm which was used to calculate the bacterial reduction as described in detail elsewhere [28]. In principle, the applied method concerning cultivation and evaluation of the microbial reduction is a adaption of a method initially described by Bechert and co-workers [29] and has been successfully used for example by Bruenke et al [30]. Doubling time was calculated for an optical density of 0.2 and 0.4.…”

Silver ion doped hydroxyapatite-coated titanium pins prevent bacterial colonization

“…aureus. [ 21 ] The most important findings of the study are that the bacterial growth was statistically higher in the broth containing uncoated pins, compared to the broth media containing silver ion doped HA-coated and pure HA-coated pins. No free silver ions were present in broth media containing silver-coated pins by atomic absorption method.…”

Titanium for Orthopedic Applications: An Overview of Surface Modification to Improve Biocompatibility and Prevent Bacterial Biofilm Formation

“…It is widely accepted that silver possesses antimicrobial properties. Titanium wire coated with a silver multilayer coating showed >4 log reduction when tested using a proliferation assay, compared with the untreated titanium against methicillin-sensitive S. epidermidis ( Fabritius et al., 2020 ). Titanium/silver hard coatings have demonstrated reduced adherence of both S. aureus and K. pneumoniae , while displaying no cytotoxic potential in vitro .…”