Working in a mouse model, scientists from The Johns Hopkins University have demonstrated that their novel nanofiber coating has successfully eradicated all traces of bacteria. The researchers indicate that their coating could be applied to a wide variety of orthopedic prostheses. A report on the study was published online the week of October 24, 2016 in Proceedings of the National Academy of Sciences.
Co-senior study author Lloyd S. Miller, M.D., Ph.D. is an associate professor of dermatology and orthopedic surgery at the Johns Hopkins University School of Medicine. He commented to OTW, “Prior to this work, most approaches only deliver a single antibiotic at a time—and the release rate of the drug is typically not well controlled.”
For three years, Dr. Miller worked with Hai-Quan Mao, Ph.D., a professor of materials science and engineering at the Johns Hopkins University Whiting School of Engineering, to create the new coating. Dr. Miller told OTW, “Our goal was to make a coating that would conform to any implant. We also wanted to effectuate a controlled delivery of two antibiotics. We used two biocompatible and bioresorbable polymers, both of which have a long safety track record and are FDA-approved for other indications. We loaded the nanofiber coating with the antibiotic rifampin in combination with one of three other antibiotics: vancomycin, daptomycin or linezolid.”
“It was necessary to combine the two antibiotics for effectiveness. Rifampin has an excellent biofilm penetrating capability, but it needs to be mixed with something that has a broad-spectrum release that lasts longer. Using rifampin alone is problematic because antibiotic resistance develops fairly quickly.”
“After two weeks, the rodents’ joints and adjacent bones were removed. We found that the bone loss that often occurs near infected joints was nonexistent in the mice that received the antibiotic-loaded coating. Past technologies have only reduced the overall bacterial burden. In this study, we were able to eradicate any trace of bacteria. There was none left on the metal or on bone.”
