PULLMAN, Wash. — Washington State University and Mayo Clinic researchers have developed an electrochemical catheter hub that could someday help prevent deadly central line-associated bloodstream infections (CLABSIs) that annually kill thousands of people around the world.
Reporting in the journal, Biotechnology and Bioengineering, the researchers showed that their e-catheter hub showed "significant antimicrobial activity," killing off a common type of bacteria that is responsible for hospital infections.
"Our idea was to produce hypochlorous acid, a common disinfectant, at a very low concentration to prevent CLABSI. It eliminated infection," said Haluk Beyenal, professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering and corresponding author on the paper.
Central venous catheters, flexible tubing that are used in many medical procedures to administer fluids or medications, are responsible for about 20 percent of bloodstream infections.
While hospitals often try to prevent the infections with careful protocols and preemptive antibiotics, the catheters can still be a breeding ground for bacteria, including varieties that are antibiotic-resistant. People handling catheters can easily introduce pathogens when they are connected or disconnected at their hubs, and the danger of infection increases for patients who have a prolonged catheterization. Bloodstream infections can become serious, leading to sepsis which causes thousands of deaths annually and are one of the top causes of death in several North American and European countries.
"During COVID-19, CLABSI rates rose by more than 50% and CLABSIs were significant contributor to increased mortality. In other words, some of the mortalities were due to CLABSI," said Beyenal.
The WSU researchers have been working for several years to use electric current to create a continual disinfectant to prevent and treat infections.
"The key challenge was whether we could make it usable and if we could control it," said Beyenal. "We needed to generate a low concentration without generating toxicity but eradicate pathogens."
The researchers used 3D printing to create a catheter hub, then incorporated small, battery-powered wearable electronics that control electrodes to produce an electrochemical reaction. The electrodes are tiny wires made of gold or titanium. When controlled electric power is added to the electrodes, a reaction occurs, converting salt water in the catheter hub to hypochlorous acid, the bacteria-killing disinfectant.
"When you use a catheter hub system, you always have to fill it up with a solution that generally includes sodium chloride (salt)," said Beyenal. "We simply use the chloride in the sodium chloride."
Hypochlorous acid is commonly used in cleaning products, including in some hand sanitizers. It is also produced naturally by white blood cells of healthy people to fight bacteria, fungi, and viruses. Instead of one application that one might use with a hand sanitizer, the e-catheter hub is able to continually produce the disinfectant.
The researchers showed the e-catheter hub killed one variety of a common bacteria that cause blood infections. The gold-based electrodes worked best for maintaining steady production of hypochlorous acid and continual killing of bacteria.
"We chose that type of bacteria (to test) because of its resistance to multiple antibiotics, its widespread presence in central venous catheters, and its ability to persist on hospital surfaces and equipment for extended periods," said Majid Al-Qurahi, first author on the paper and a graduate student in the Voiland School.
The researchers will soon be testing the catheter hub in animals and with other varieties of bacterial infection and at higher levels. They also are investigating the maximum concentration of disinfectant that they can produce to kill off bacteria without causing any bodily harm.
"The catheter is like a direct gateway to the bloodstream, so we need to make sure everything is safe," said Al-qurahi. The work was funded by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health.
