Evaluation of a Murine Model for Testing Antimicrobial Implant Materials in the Blood Circulation System

Abstract

Medical device-related infections are becoming a steadily increasing challenge for the health care system regarding the difficulties in the clinical treatment. In particular, cardiovascular implant infections, catheter-related infections, as well as infective endocarditis are associated with high morbidity and mortality risks for the patients. Antimicrobial materials may help to prevent medical device-associated infections and supplement the currently available therapies. In this study, we present an easy-to-handle and simplified in vivo model to test antimicrobial materials in the bloodstream of mice. The model system is composed of the implantation of a bacteria-laden micro-stent scaffold into the murine tail vein. Our model enables the simulation of catheter-related infections as well as the development of infective endocarditis specific pathologies in combination with material testing. Furthermore, this in vivo model can cover two phases of the biofilm formation, including both the local tissue response to the bacterial biofilm and the systemic inflammatory response against circulating bacteria in the bloodstream that detached from a mature biofilm.

Novel dalbavancin-PLLA implant coating prevents hematogenous Staphylococcus aureus infection in a minimally invasive mouse tail vein model

“…Further examination did not reveal any major histological differences between the rifampicin/ minocycline and the dalbavancin groups (Figure 5). Unlike in the study by Moerke et al (Moerke et al, 2021), in which sterile and contaminated implants were used without antibiotic coating, considerable differences were observed between the groups in terms of the formation of inflammatory aggregates and the disintegration of surrounding tissue (Figure 5).…”

“…Trichrome staining showed an intact vascular endothelium at both time points examined, with no evidence of a local inflammatory reaction. In contrast, without antibiotics a marked inflammatory reaction was observed ( Figure 5 ) ( Moerke et al, 2021 ).…”

“… Histological trichrome staining of tail cross sections was performed after 6 and 48 h. Representative images of mice tails that received implants without antibiotic coating (excerpted from Moerke et al ( Moerke et al, 2021 )), coated with rifampicin/minocycline, and dalbavancin are shown; bars 100 µm or 50 μm; Magnification, × 200 or x 400. Different color expression is due to performing the staining on different days.…”

“…We expanded this study and developed an in vivo contamination model to test the anti-microbial potential of implant materials ( Moerke et al, 2021 ). In association with the validation of the in vivo model, the aim of this present study was to compare a novel antibiotic coating based on dalbavancin as a long shelf-life single agent with a well described local drug depot of rifampicin and minocycline.…”

In Situ Imaging and Anti-inflammation of 3D Printed Scaffolds enabled by AIEgen

“…[16][17][18] Bacteria can also form colonies, so-called "biofilms", on the implanted devices, which can cause widespread infections such as endocarditis. [19] Given the production process and components, it is difficult for naked 3D printed scaffolds to own antibacterial properties. [20][21][22] Antibiotics are often used clinically for sterilization, but the special location of scaffolds and the drug resistance of bacteria result in low efficacy for treatment of bacterial inflammation caused by implanted scaffolds.…”