Infections following surgery are a serious and potentially fatal complication. Current methods of combatting infections, especially drug-resistant pathogens, often fall short. New research, looking at a narrow band of ultraviolet light might offer a safe and simple solution.
A clean surgery refers to an operation carried out in a sterile environment where no inflammation, infection, or unexpected tissue damage occurs.
Even in these ideal situations, an estimated 0.5-10 percent of procedures result in surgical-site infections (SSI).
That equates to around 275,000 patients in the United States per year. Individuals with SSIs have a mortality rate twice that of someone without an infection.
A patient with an SSI stays in hospital, on average, 1 week longer than someone without an infection. In total, SSIs cost the U.S. up to $10 billion a year in patient hospital costs.
An estimated 8,200 deaths are attributed to SSIs each year in the U.S.
Efforts to reduce the number of infections have had limited success; with the rise of drug-resistant bacteria, such as MRSA (methicillin-resistant Staphylococcus aureus), the problem shows no signs of slowing, and some scientists are concerned that the issue may worsen.
Researchers at Columbia University Medical Center have turned their attention to ultraviolet (UV) light as a way to fight these surgical invaders.
Scientists have known for some time that UV light has the ability to kill bacteria, even pathogens like MRSA, referred to as “superbugs.” However, the UV lamps required for this type of treatment also pose a significant health threat to patients and medical staff. They can cause a number of health issues, most often damaging the eyes and skin. For instance, UV light is known to induce skin cancer and cataracts.
Over the last few years, researchers led by David J. Brenner, Ph.D., have investigated narrower bands of UV light to find an alternative that is still toxic to pathogens (cytotoxic), but safe for human skin and eyes.
Brenner decided to investigate “far-UVC light,” a narrow band of UV light with a wavelength of around 200 nanometers.
They chose this specific range of light because it cannot penetrate the dead layer of skin that coats living, growing skin, or the outer layer of the eye. Light of wavelengths around 200 nanometers is safely absorbed by proteins and other molecules in the skin and is unable to reach the nucleus of the cells.
However, bacterial cells are 10-25 times smaller than human cells and, therefore, still susceptible to the far-UVC’s damaging rays.
In a previous study, the team found that this far-UVC light is just as effective at killing MRSA as conventional germicidal UV light. The positive results spurred the team on to investigate whether this range of wavelength might be beneficial in a clinical setting.
Although Brenner and his team had previously shown that far-UVC light did not seem to cause damage in a 3-D model of human skin, they wanted to investigate its effects on living skin. To do this, they used hairless mice, whose skin is known to respond in a very similar way to humans’.
The findings demonstrated that far-UVC light did not damage healthy skin cells.
“Our findings offer a potential practical pathway towards significantly reducing surgical site infection rates without risk to the health and safety of patients and medical personnel.”
David J. Brenner, Ph.D., lead author
Next, the team plans to extend this research to surgical settings and larger animals, including humans. Further down the line, they hope to investigate the use of far-UVC in the battle against airborne pathogens, such as tuberculosis and influenza.
If results of the next phases of trials are successful, they could herald a safer, more cost-effective way of managing infections and pathogens in a number of settings. The authors are quick to note that far-UVC light will not completely remove the risk of SSIs, but they also hope that it will save a significant amount of time, money and, most importantly, lives.