The advantages of blue light are that while most light spectra at high irradiance can reduce miucrobial populations by inducing cell death (a photothermal effect), it is blue light which shows the greatest promise. Research suggests that blue light has a strong efficacy over a range of bacterial species, such as identified pathogens like Pseudomonas aeruginosa, Helicobacter pylori, and methicillin-resistant Staphylococcus aureus (MRSA). These bacterial-killing effects are observed even at the low irradiance.
One reason why there is interest in blue light is due to the rise in multi-drug antimicrobial resistance among pathogenic organisms, leading to a situation where infections that were one straightforward to treat are now proving challenging. Furthermore, rates of antimicrobial resistance are increasing in most parts of the world. Concerning, patterns of resistance are increasing among bacteria that cause common infections, such as pneumonia, urinary tract, cutaneous, and mucosal infections.
New research looking at the application of blue light comes from the University of Trieste in Italy. Here the researchers report on the application of blue laser light for eradicating Pseudomonas aeruginosa cells, including cells in mature biofilms, with minimal toxicity to mammalian cells. The findings suggest that inducing oxidative stress is the mechanism by which bbacterial cells are killed via the blue light. The technique has future therapeutic potential in the form of blue laser phototherapy for the treatment of highly-infected wounds.
The research is published in the journal NPJ Biofilms and Microbiomes, titled “Blue laser light inhibits biofilm formation in vitro and in vivo by inducing oxidative stress.”
A further application using light relates to a technique of using gold nanoparticles in light-heat conversion processes, to help reduce infection rates when a medical device is inserted into a patient’s body. The use of light helps bacteria to detach from surfaces, making them easier to kill.
