May 2022

In the United States, 1 in every 25 patients contracts a healthcare-associated infection (HAI), leading to almost 100,000 deaths per year.

A main cause of HAIs is biofilm-forming indwelling medical devices. Indwelling medical devices (also called invasive devices) are instruments placed within an organ, tissue, or bodily passage for a long period of time.

Examples include urinary and vascular catheters, intracardiac devices, prosthetic mesh, endotracheal tubes, and wound drains. If not properly designed and maintained, these devices can become a perfect breeding ground for microbes. Indwelling devices colonized by bacteria as biofilms cause chronic local infections and increase the likelihood of sepsis from bacteria spilling into the bloodstream.

To prevent infections, many indwelling medical devices now incorporate antimicrobial agents that prevent microbial adhesion and growth. Active ingredients for such applications must be chemically stable, exert antimicrobial activity across a broad range of microbes, and have minimal toxicity to the tissues they contact. Common active ingredients include silver, chlorhexidine, and various antibiotics.

Indwelling devices with antimicrobial-treated materials require extensive testing to demonstrate efficacy, generally under laboratory conditions simulating patient use. Our Medical Device Efficacy Team tests a device or article’s antimicrobial performance using modifications of various standardized test methods or completely customized procedures when needed:

  • ISO 22196: This method was developed for plastic and non-porous surfaces. It challenges a device or article’s ability to inhibit or kill microorganisms with a 24-hour contact period. The method can be easily modified to simulate patient use, such as by adding human serum during the challenge period. This test can also be extended to other items such as metals, and even for viral testing.
    AATCC 100: Some medical polymers and wound dressings behave like porous fabrics, so this method, originally designed for textiles, is often a good starting point. The method is applicable to devices with infused antimicrobials as well as textile-like devices woven with a certain proportion of antimicrobial threads.
    Medical manufacturers continue to develop novel antimicrobial technologies and delivery systems to remain competitive in the industry. The research and product development these companies do is critical to infection prevention.

To learn more about medical device testing, please contact Hannah Klug, our Medical Device Efficacy Team Lead at [email protected].