A rising prevalence of cardiovascular disease has generated substantial growth in the use of medical implants, such as vascular grafts. Unfortunately, the increased use of implanted devices has been accompanied by more device-associated infections, serious complications, and death. A study in The American Journal of Pathology reports the detrimental aftereffects of infected grafts, including the formation of biofilms that can shelter bacteria and function as a source of recurrent infection. This new research should enable researchers to develop better strategies to diagnose and manage vascular graft infections.
"Staphylococcus aureus (S. aureus) is one of the leading causes of infected grafts because it readily adheres to the surface of the implanted device and forms thick biofilm layers. Biofilms can shelter bacteria from the patient's immune responses or antibiotic treatment. These biofilm layers are difficult to detect because they are often unaccompanied by clinical symptoms," noted lead investigator Bettina Löffler, MD, director of the Institute of Medical Microbiology, Jena University Hospital in Germany. "Currently, there are no effective treatment strategies against these infections. Biofilms require antibiotic concentrations up to 1000 times higher than normal and these concentrations are not clinically feasible. It is of great importance to understand the underlying pathogenesis of biofilm formation on vascular grafts in order to find quick and effective treatment possibilities without having to resort to invasive procedures such as surgical removal."
The researchers developed a new mouse model that more closely mimics the human condition. The catheter is placed within a blood vessel (the right carotid artery) and bacteria reach the catheter via the blood stream (bacteria are introduced into tail veins seven days after the catheter is inserted). "Just as in humans, with this model the bacteria need to overcome the stress of the blood flow, the shear stress induced by the blood flow, and the host's immune system to form a biofilm infection on the catheter," explained Löffler. By establishing this novel model in mice investigators opened up the possibility to use the vast array of genetically manipulated mice available, which will allow the study of many different aspects of the disease and identification of better and more reliable treatment and detection strategies for vascular graft infections.
An interesting finding of the study was that all S. aureus strains tested formed biofilms in vivo, regardless of whether they formed high biofilm levels in cell culture. This finding demonstrates that colonization of vascular grafts in vivo is a general characteristic of all S. aureus infections and that these bacteria are highly adaptive to their environment.
Using PET imaging, the investigators discovered a high level of inflammation at the site of the catheter during vascular graft infections. MR imaging revealed that blood flow velocity was decreased through the catheter due to infection and biofilm formation.
"Our model takes all steps of the pathogenesis of infected implants into account and closely represents the clinical situation," said Löffler. "It provides a solid platform for microbiological and immunological experiments that could provide crucial insights into the pathogenesis as well as the diagnosis and treatment of these devastating infections."
Source: Elsevier Health Sciences
Product Locator: Spring and Early Mother's Day Gift Guide for Infection Prevention Personnel
March 27th 2024Whether it's a spring holiday, birthdays, or no reason at all, infection prevention personnel love to give and receive gifts that help at the end of a stressful day. Infection Control Today® offers some gift ideas for infection prevention personnel and their families.
Catching Up With Vangie Dennis, AORN 2022-2023 President at AORN 2024
March 26th 2024Infection Control Today (ICT) had the privilege of catching up with Vangie Dennis, MSN, RN, CNOR, CMLSO, at the Association of periOperative Registered Nurses' (AORN’s) International Surgical Conference & Expo 2024. As the former president of AORN and an esteemed figure in perioperative services, Vangie Dennis shared insights into her recent endeavors and the exciting new chapter she's embarked upon.
How To Optimize Your Time Management Strategies for the Busy Infection Preventionist
March 25th 2024Is your calendar resembling a chaotic masterpiece of overlapping tasks? Join the club of infection preventionists striving to balance responsibilities. Dive into proven strategies from a fellow infection preventionist to reclaim control of your time, streamline tasks, and boost productivity effectively. This is an IP Lifeline article.
CenTrak Unveils Revolutionary BLE Multi-Mode Platform for Health Care RTLS Solutions
March 22nd 2024CenTrak, the industry leader in real-time location technology, introduces the groundbreaking BLE Multi-Mode Platform, setting a new standard for Real-Time Location Systems (RTLS) in health care. Discover how this innovative solution enhances location data precision and streamlines operations for health care organizations.