Blue light could be a new weapon against drug-resistant bacteria.
Other researchers are investigating whether combinations of existing antibiotics might be more effective against certain superbugs.
Some scientists are looking to innovative technologies, striving to find alternative methods to destroy these increasingly deadly pathogens.
Recently, scientists from Purdue University in West Lafayette, IN, and Boston University in Massachusetts investigated the potential power of blue light. They recently published their findings in the journal Advanced Science.
Why blue light?
The scientists focused their research on, arguably, the most well-known strain of antibiotic-resistant bacteria — methicillin-resistant Staphylococcus aureus (MRSA).
Doctors can treat most of these infections successfully, but severe MRSA infections can result in amputation or even death.
S. aureus, along with other strains of bacteria, produces pigments that play a role in protecting the bacteria from attack.
Scientists have found that S. aureus contains a golden pigment called staphyloxanthin (STX) that protects it against neutrophils — a type of white blood cell that plays a pivotal role in the fight against pathogens.
A process called photobleaching can reduce levels of this pigment. This weakens the bacterium's membrane, which makes it easier to kill; this limits the amount of damage that the bacteria can cause.
Some researchers have already looked for ways to knock out STX using medication. One study, for instance, looked at an existing antifungal drug. However, drug-based approaches have not, so far, yielded improved treatments for antibiotic-resistant infections. Finding a way to remove STX's teeth without drugs might provide a new approach to these difficult-to-treat pathogens.
The scientists found, accidentally, that if they photobleached MRSA using blue light, they could break down STX. The photobleaching caused their membrane to become more permeable, rendering the bacteria defenseless.
After photobleaching, the bacteria were susceptible to even relatively mild antiseptics, such as hydrogen peroxide.
They tested the blue light approach in a range of scenarios, including cultured bacteria, MRSA-infected immune cells, biofilms of S. aureus, and two models of wound infection in mice.
Perhaps the most interesting part of this discovery is the simplicity of the technology. Prof. Seleem explains that "[t]he device itself is very small and easy to use. We're hoping that in the next few years, anyone could carry it around in their purse."
"This new tool can treat any superficial wound infected with MRSA, which are typically very difficult to treat."
Prof. Mohamed Seleem
The authors also hope that in the future, this technology might be useful against other types of bacteria because "pigmentation is a hallmark of multiple pathogenic microbes."
Of course, before medical practitioners can use the device, researchers will need to carry out extensive clinical trials in humans. Although this process is likely to take some time, the principal is intriguing.
If scientists can find a way to weaken drug-resistant bacteria in a way that does not cause adverse events, it would be a substantial step forward in the war against superbugs.