PROVIDENCE – Brown University researchers have developed a new antibacterial coating for intravascular catheters that could help prevent catheter-related blood infections, the most common type of hospital-acquired infection.
Venous access by catheter is used for hemodynamic monitoring, renal replacement therapy, nutritional support, and medication administration, according to the National Institutes of Health. More than 150 million intravascular catheters are implanted each year in the United States, and infections stemming from implants develop in 250,000 patients a year, according to the NIH. Such infections are fatal in up to 25 percent of cases, and even when successfully treated can add up to millions of dollars in extended hospital stays, according to Brown University’s statement on the research.
“These kinds of infections are a major burden for hospitals, health care providers and most of all for patients,” said Anita Shukla, an assistant professor of engineering at Brown and corresponding author of a new paper describing the work. “We wanted to develop a coating that could both kill planktonic [free-floating] bacteria and prevent colonization of bacteria on surfaces. The initial data that we gathered for this paper shows that we have something really promising.”
In the paper, the researchers show that a polyurethane coating that can be readily applied to medical surfaces gradually releases a drug called auranofin that can kill methicillin-resistant Staphylococcus aureus, or MRSA, bacteria for nearly a month in lab tests. Other antibacterial coatings tend to lose their effectiveness after two weeks at most, often because they release their drug payload too quickly. Other coatings also tend to use traditional antibiotics, raising concerns about antibiotic resistance over long-term use.
The tests also showed that the coating could prevent the formation of MRSA biofilms, which, once established, are especially resilient to antimicrobial treatment, according to Brown’s announcement.
Auranofin was originally developed and approved by the U.S. Food and Drug Administration to treat arthritis, but studies by Warren Alpert Medical School’s Dr. Eleftherios Mylonakis and Beth Fuchs and others have shown that the drug is also effective at killing MRSA and other dangerous microbes. It also works in ways that make it hard for bacteria to evolve a natural resistance, according to Brown.
To make the coating, the researchers dissolved polyurethane and concentrations of auranofin in a solution, which was then deposited onto a catheter. The solvent is then evaporated away, leaving a stretchable yet durable polymer coating, according to the university’s announcement.
To test the coating’s effectiveness, the researchers placed coated catheters in MRSA both in solution and on agar plates, where MRSA bacteria thrive. The experiments showed that the coatings were able to inhibit MRSA growth for up to 26 days, depending on the initial concentration of auranofin used in the coating. The researchers also used bioluminescence imaging to look for signs of biofilm formation. Those experiments showed that the coatings prevent any trace of biofilm. For comparison, the researchers also tested a catheter loaded with a more traditional antibiotic, highly effective against free-floating MRSA, which proved unable to prevent biofilm formation.
The research, which is published in Frontiers in Cellular and Infection Microbiology, is a collaboration between Shukla’s lab in Brown’s School of Engineering and the labs of Mylonakis and Fuchs in the Division of Infectious Diseases in Brown’s Warren Alpert Medical School, according to the statement.
“It’s a perfect collaboration between medicine and engineering,” Shukla said of the partnership. “[Mylonakis and Fuchs] come to us with the types of problems that they commonly see in the clinic. As an engineering lab focused on developing new biomaterials for drug delivery, we can then work on engineering solutions to the problems they bring us.”
Rob Borkowski is a PBN contributing writer.
