Testing of antibiotic releasing implant coatings to fight bacteria in combat-associated osteomyelitis – an in-vitro study

Purpose Surgical procedures to prevent osteomyelitis after trauma can be supported by local application of antibiotics. This in-vitro study investigated the release and impact of antibiotics from implant coatings against bacteria associated with combat-related osteomyelitis. Methods K-wires were coated with poly(D,L-lactide) and ciprofloxacin, gentamicin, colistin, daptomycin or cefoxitin in different concentrations. The release was quantified and antimicrobial activity tested for different gram-positive or gram-negative bacteria, alone and in combination. To exclude toxic effects, primary osteoblast-like cells were exposed to antibiotic coating concentrations. Results All antibiotics alone and in combination showed an initial burst release with dose dependent antimicrobial activity and no negative effects on osteoblast-like cells, except for cefoxitin. Conclusions Implant coatings can be customized with single or double antibiotic coatings to effectively fight different bacteria and also mixed infections in the treatment of a combat-acquired osteomyelitis. However, optimal drug load and degradation behaviour of individual antibiotics have to be considered.