42nd ICAAC, September 27-30, 2002 San Diego, California

Interscience Conference on Antimicrobial Agents and Chemotherapy, a meeting for the American Society for Microbiology

Protecting medical devices from infection: A pre-emptive strike  (Paper K-1375, Session 152)  Abstract

Lori Burrows
U. of Toronto
Toronto, ON
Canada
(416) 813-7546
lori.burrows@sickkids.ca
 
Modern health care requires the frequent use of a myriad of medical devices ranging from intravenous and urinary catheters to artificial organs. A common problem with medical devices is that they provide a place for microorganisms to attach and grow, leading to drug-resistant infections. One strategy to prevent such infections is killing microorganisms as soon as they attach to the surface of the device, before they have a chance to get established. We have developed a coating for medical devices that acts as a glue for drugs, allowing various types of antibiotics and antimicrobial substances to bind to a surface and then release slowly over several days to weeks, killing microorganisms. This coating is a versatile drug delivery system that can be applied to many medical devices that are prone to infection.

The development of this coating arose through a collaboration between biochemists, microbiologists and physicians at the University of Toronto, and has led to the formation of a start-up company called UroTeq Inc. A presentation describing the coating’s drug-binding capacity is taking place at the 42nd Annual Meeting of the Interscience Conference on Antimicrobial Agents and Chemotherapy in San Diego, California on September 29, 2002.

The research team showed that several chemically-distinct antimicrobial substances or combinations of substances can bind to the coating and subsequently be released over time, killing bacteria in the immediate environment. Plastic surfaces treated with the coating were incubated in solutions containing serial dilutions of antibiotics, disinfectants or antimicrobial peptides.

After allowing the drugs to bind to the coating, the surfaces were rinsed to remove unbound drug and immersed in a suspension of bacteria. The ability of the coating to kill bacteria both floating in the suspension and attempting to attach and grow on the plastic surface was measured by counting the number of bacteria surviving in each phase after an overnight incubation. Silicone catheter segments treated with the coating were also incubated and monitored. The coating was able to bind and then release each of the chemically diverse compounds, showing its versatility.

Researchers also demonstrated that the coating has no harmful effects on tissue in an animal model of urinary catheterization. The animal models were catheterized for five days with either regular silicone catheters or catheters treated with the coating and incubated in ciprofloxacin. Examination of the animals’ urethras and bladders after removal of the catheters showed no difference between treated and control animals.
This coating is able to bind and deliver structurally unrelated substances and will be useful for the generation of antimicrobial versions of pre-existing medical devices. The ability of the coating to bind a variety of compounds could be extended in the future to include other therapeutic substances.