Using oxygen to kill pathogenic bacteria

Scientists have turned to an unusual source in order to tackle the problem of pathogenic bacteria – oxygen. This is in relation to MRSA, which is associated with hospital derive infections, in particular.

The scientists have reported their research findings to the 256th National Meeting & Exposition of the American Chemical Society, which took place in mid-August 2018. The meeting attracted around estimated 13,000 chemists, chemical engineers, academicians, graduate and undergraduate students, and other related professionals.

The new method makes use of light to activate oxygen. This leads to the death of bacteria, including the means to destroy antibiotic-resistant bacteria. The research is focused on the inactivation of methicillin-resistant Staphylococcus aureus (MRSA).

MRSA is responsible for several difficult-to-treat infections in humans. MRSA infections mainly affect people who are staying in hospital. Infections can be serious. Treatment is through antibiotics, but there is a growing concern that some types of pathogenic bacteria are increasingly resistant to antibiotics.

Commenting on the research to Biotechniques.com, lead researcher Professor Peng Zhang, from the University of Cincinnati, said: “Instead of resorting to antibiotics, which no longer work against some bacteria like MRSA, we use photosensitizers, mostly dye molecules, that become excited when illuminated with light.”

Photodynamic inactivation of bacteria is considered as one of the promising approaches to overcome the problem of drug resistance. The process utilizes a photosensitizer, oxygen, and light of appropriate wavelength.

With the method, the photosensitizers (a molecule that produces a chemical change in another molecule in a photochemical process) convert oxygen into reactive oxygen species that attack the bacteria. Reactive oxygen species can trigger significant damage to cell structures. This process was improved by the researchers through the inclusion of metal nanoparticles, which promote the generation of more reactive oxygen species and direct the process of cell killing to specific sites on the bacterial cell wall. The application of red light further boosts the efficiency of the kill process.

There is also a potential future application with the technology in terms of treating cancer by oxidizing cancerous cells. The technology is being developed in both gel and spray form.
Posted by Dr. Tim Sandle, Pharmaceutical Microbiology