Hospitals are places of healing, but each year about 200,000 to 300,000 patients pick up infections in their surgical wounds, making them 60% more likely to spend time in the ICU than infection-free patients, and contributing to $3 billion to $10 billion annually in health care costs.
Doctors have long used ultraviolet light at 200 nanometers (nm) to 400 nm to zap bacteria that might be residing on surgical instruments; but the UV wavelengths are too damaging to human DNA to use in patient settings. The genetic scrambling triggered by the light can lead to cancer and cataracts.
But researchers from Columbia University Medical Center have found that a narrow spectrum of UV light — at 207 nm — can kill bacteria like methicillin-resistant S. aureus (MRSA) while leaving human skin unharmed. The scientists report in the journal PLOS ONE that UV exposure at this level does not invade the nucleus of human cells, where its DNA is housed, and does not reach cells in the skin and eyes that are particularly sensitive to ultraviolet damage.
The experiment was done on cell cultures that modeled human skin, but the team was encouraged by the fact that the 207 nm light effectively dispatched MRSA with a 1,000-fold lower rate of destroying the skin cells. More tests are needed before the lamp can be tested on patients, but it could be the first step toward shining light on the problem of hospital infections.