NEW YORK (Reuters Health) - In a rabbit model of deep bone infection caused by Staphylococcus aureus, local delivery of ciprofloxacin via a bioabsorbable implant containing bone defect fillers efficiently treated the infection, Finnish researchers report in the April issue of Antimicrobial Agents and Chemotherapy.
“This novel multifunctional implant,” senior investigator Dr. Hannu T. Aro told Reuters Health, “consists of a bioresorbable polymer with optimal properties for controlling the sustained release of the antibiotic.” The composite also contains a silica-based biomaterial component, “for promotion of bone repair” after eradication of the infection.
“Pilot studies,” he added, “have shown that the implant releases the antibiotic into the bone at therapeutic levels in a controlled manner over a period of 300 days and there is no significant systemic exposure measured from circulating blood.”
Dr. Aro of the University of Turku and colleagues report that bacteriological analysis confirmed the eradication of S. aureus from bone in all actively treated animals but in none of the sham-treated and untreated control animals.
However, the authors point out that three animals given the implant developed soft tissue infections, “confirming that there is still a need for systemic antimicrobial treatment in addition to local therapy for a certain time period.”
They investigators also “verified the osteoconductive properties of the bioactive glass microspheres within the composite,” but say long-term follow-up of the osteoconductive response is needed to make any definitive conclusions about the bone-restoring potential.
Summing up, Dr. Aro noted that “despite continuous advances in the surgical and antimicrobial armamentarium, the treatment of bone infections remains a challenge even in specialized centers.”
This multifunctional implant, he concluded, “represents a novel targeted therapy for bone infections and may ultimately cut the high costs of the current treatment protocols and fight against the spread of resistant bacterial strains.”
Source: Antimicrob Agents Chemother 2005;49:1502-1508. [ Google search on this article ]
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