Novel Antibiotic-loaded Point-of-care Implant Coating Inhibits Biofilm

Abstract

Background Orthopaedic biomaterials are susceptible to biofilm formation. A novel lipid-based material has been developed that may be loaded with antibiotics and applied as an implant coating at point of care. However, this material has not been evaluated for antibiotic elution, biofilm inhibition, or in vivo efficacy.Questions/purposes (1) Do antibiotic-loaded coatings inhibit biofilm formation? (2) Is the coating effective in preventing biofilm in vivo? Methods Purified phosphatidylcholine was mixed with 25% amikacin or vancomycin or a combination of 12.5% of both. A 7-day elution study for coated titanium and stainless steel coupons was followed by turbidity and zone of inhibition assays against Staphylococcus aureus and Pseudomonas aeruginosa. Coupons were inoculated with bacteria and incubated 24 hours (N = 4 for each test group). Microscopic images of biofilm were obtained. After washing and vortexing, attached bacteria were counted. A mouse biofilm model was modified to include coated and uncoated stainless steel wires inserted into the lumens of catheters inoculated with a mixture of S aureus or P aeruginosa. Colony-forming unit counts (N = 10) and scanning electron microscopy imaging of implants were used to determine antimicrobial activity. Results Active antibiotics with colony inhibition effects were eluted for up to 6 days. Antibiotic-loaded coatings inhibited biofilm formation on in vitro coupons (log-fold reductions of 4.3 ± 0.4 in S aureus and 3.1 ± 0 for P aeruginosa in phosphatidylcholine-only coatings, 5.6 ± 0 for S aureus and 3.1 ± 0 for P aeruginosa for combinationloaded coatings, 5.5 ± 0.3 for S aureus in vancomycinloaded coatings, and 3.1 ± 0 for P aeruginosa for amikacinloaded coatings (p \ 0.001 for all comparisons of antibiotic-loaded coatings against uncoated controls for both bacterial strains, p \ 0.001 for comparison of antibioticloaded coatings against phosphatidylcholine only for S aureus, p = 0.54 for comparison of vancomycin versus combination coating in S aureus, P = 0.99 for comparison of antibiotic-and unloaded phosphatidylcholine coatings in P aeruginosa). Similarly, antibiotic-loaded coatings reduced attachment of bacteria to wires in vivo (log-fold

Surface Treatments and Functional Coatings for Biocompatibility Improvement and Bacterial Adhesion Reduction in Dental Implantology

“…Using as a carrier a novel lipid-based material that may be applied as an implant coating at point of care, antibiotics such as amikacin and vancomycin were loaded and tested against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa [89]. Very promisingly, antibiotic-loaded coatings reduced attachment of bacteria in vivo, although future evaluations are needed to include preclinical models to confirm therapeutic efficacy.…”

Impact of sarA and Phenol-Soluble Modulins on the Pathogenesis of Osteomyelitis in Diverse Clinical Isolates of Staphylococcus aureus

“…Our laboratories have placed a major emphasis on overcoming this problem by exploring alternative means for early diagnosis (3,10), developing improved methods for localized antibiotic delivery for the prevention and treatment of infection (11)(12)(13)(14), and identifying the bacterial factors that contribute to the prominence of S. aureus as an orthopedic pathogen. With respect to the last area of exploration, our studies have led us to place a primary emphasis on the staphylococcal accessory regulator (sarA), mutation of which limits biofilm formation to a greater degree than mutation of any other regulatory locus that we have examined (11,15).…”

CORR Insights®: Antibiotic-tolerant Staphylococcus aureus Biofilm Persists on Arthroplasty Materials

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