BackgroundImplant-related infections represent one of the most severe complications in orthopaedics. A fast-resorbable, antibacterial-loaded hydrogel may reduce or prevent bacterial colonization and biofilm formation of implanted biomaterials.Questions/purposesWe asked: (1) Is a fast-resorbable hydrogel able to deliver antibacterial compounds in vitro? (2) Can a hydrogel (alone or antibacterial-loaded) coating on implants reduce bacterial colonization? And (3) is intraoperative coating feasible and resistant to press-fit implant insertion?MethodsWe tested the ability of Disposable Antibacterial Coating (DAC) hydrogel (Novagenit Srl, Mezzolombardo, Italy) to deliver antibacterial agents using spectrophotometry and a microbiologic assay. Antibacterial and antibiofilm activity were determined by broth microdilution and a crystal violet assay, respectively. Coating resistance to press-fit insertion was tested in rabbit tibias and human femurs.ResultsComplete release of all tested antibacterial compounds was observed in less than 96 hours. Bactericidal and antibiofilm effect of DAC hydrogel in combination with various antibacterials was shown in vitro. Approximately 80% of the hydrogel coating was retrieved on the implant after press-fit insertion.ConclusionsImplant coating with an antibacterial-loaded hydrogel reduces bacterial colonization and biofilm formation in vitro.Clinical Relevance A fast-resorbable, antibacterial-loaded hydrogel coating may help prevent implant-related infections in orthopaedics. However, further validation in animal models and properly controlled human studies is required.

Microbiological investigations showed a positive culture in 430 out of 1540 venous catheters and shunts for dialysis. In 21 cases, a mixed culture with two different specific organisms was present. Of the total of 451 isolated organisms, 362 were gram-positive cocci and only 56 gram-negative bacillaceae. Staphylococcus epidermidis was by far the most frequent pathogen (n = 228), staphylococcus aureus in second place (n = 94). Among the gram-negative organisms, germs of the Klebsiella-Enterobacter group and Pseudomonas aeruginosa dominated. Staphylococcus aureus represented 31% of all germs isolated from Scribner shunts and Brescia fistulas. On the other hand the causative organism could be isolated in only 18% of the infected venous catheters. Staphylococcus aureus was the most frequent pathogen in septicemia due to catheters; in 16 out of 24 patients this microorganism was found in both cultures drawn from the blood and from the catheter. In 16 cases, a venous catheter led to septicemia, a shunt for chronical dialysis in 2 cases only. The frequency of infections caused by catheters can be significantly lowered by prudent care of the site of insertion, sterile handling and short indwelling time.