Anti-biofilm activity of antibiotic-loaded Hylomate®

The identity of implant materials governs the antimicrobial efficacy of SET-M33

The physical and chemical properties of implanted materials play a key role in their interaction with synthetic peptides that exert antimicrobial activity. In this study, we explored the diffusion properties and efficacy of the SET-M33 antimicrobial peptide in combination with artificial substrates, comprising cardiac implantable electronic devices (CIEDs) or porous protective envelopes. We found that porous materials, such as biosynthesized cellulose, polymeric meshes, and electrospun membranes, were conducive to SET-M33 diffusion. The diffusion dynamics was controlled by the intrinsic fibrous architecture of the materials. Biosynthesized cellulose supported the peptide's antimicrobial activity against E. coli and S. aureus. The efficacy of SET-M33 was instead reduced when combined with the other tested porous membranes and non-porous CIED interfaces, such as titanium and silicone. On the other hand, the low porosity of biosynthesized cellulose membranes, while effective in retaining the drug, diminished diffusion and thus peptide availability. In light of these findings, the implications for the use of antimicrobial peptides in the prevention of CIED surgical pocket infections are discussed.

Impact of Healthcare-Associated Infections Connected to Medical Devices-An Update

Healthcare-associated infections (HAIs) are caused by nosocomial pathogens. HAIs have an immense impact not only on developing countries but also on highly developed parts of world. They are predominantly device-associated infections that are caused by the planktonic form of microorganisms as well as those organized in biofilms. This review elucidates the impact of HAIs, focusing on device-associated infections such as central line-associated bloodstream infection including catheter infection, catheter-associated urinary tract infection, ventilator-associated pneumonia, and surgical site infections. The most relevant microorganisms are mentioned in terms of their frequency of infection on medical devices. Standard care bundles, conventional therapy, and novel approaches against device-associated infections are briefly mentioned as well. This review concisely summarizes relevant and up-to-date information on HAIs and HAI-associated microorganisms and also provides a description of several useful approaches for tackling HAIs.

On the function of biosynthesized cellulose as barrier against bacterial colonization of VAD drivelines

Bacterial colonization of drivelines represents a major adverse event in the implantation of left ventricular assist devices (L-VADs) for the treatment of congestive heart failure. From the external driveline interface and through the skin breach, pathogens can ascend to the pump pocket, endangering the device function and the patient’s life. Surface Micro-Engineered Biosynthesized cellulose (BC) is an implantable biomaterial, which minimizes fibrotic tissue deposition and promotes healthy tissue regeneration. The topographic arrangement of cellulose fibers and the typical material porosity support its potential protective function against bacterial permeation; however, this application has not been tested in clinically relevant animal models. Here, a goat model was adopted to evaluate the barrier function of BC membranes. The external silicone mantle of commercial L-VAD drivelines was implanted percutaneously with an intervening layer of BC to separate them from the surrounding soft tissue. End-point evaluation at 6 and 12 weeks of two separate animal groups revealed the local bacterial colonization at the different interfaces in comparison with unprotected driveline mantle controls. The results demonstrate that the BC membranes established an effective barrier against the bacterial colonization of the outer driveline interface. The containment of pathogen infiltration, in combination with the known anti-fibrotic effect of BC, may promote a more efficient immune clearance upon driveline implantation and support the efficacy of local antibiotic treatments, therefore mitigating the risk connected to their percutaneous deployment.