Shining Light on New Treatment for Antibiotic Resistant Superbugs

In this file image an agar plate of the superbug Staphylcocus epidermidis is examined in Melbourne on Sept. 4, 2018. William West/AFP/Getty Images
Updated:
Superbugs face a new threat as scientists from the University of South Australia (UniSA) develop a light-activated treatment that destroys some of the most infamous and potentially deadly bacteria globally.
The antimicrobial light therapy was tested on defiant infections caused by antibiotic-resistant (AMR) strains of staphylococcus aureus (Golden Staph) and pseudomonas aeruginosa, two of the six most lethal superbugs in 2019.  The treatment was discovered to eliminate staphylococcus aureus and pseudomonas aeruginosa by 500,000-fold and 100,000-fold, respectively.
Lead researcher at UniSA, Muhammed Awad PhD, said in a university release that the new treatment could be a game-changer for millions of people globally.

“Golden staph and pseudomonas aeruginosa are both highly transmissible bacteria, commonly found on people’s skin," Awad said.

“But if they get into the blood, they can lead to sepsis or even death,” he continued.

According to Awad, hospital patients, particularly those with wounds or catheters, or those on ventilators, are at a higher risk of being subjected to these bacteria. He said that although antibiotics may help, their extensive use has led to waves of microbial resistance, often making them ineffective.
AMR makes infections increasingly more difficult or sometimes impossible to treat, resulting in the deaths of many people. In 2019, an estimated 1.27 million people died as a result of antimicrobial resistance, exceeding the death tolls of HIV/AIDS and malaria. Additionally, of those 1.27 million deaths, 929,000 were caused by the six most lethal superbugs, a group that includes staphylococcus aureus and pseudomonas aeruginosa.
The World Health Organisation declared in 2019 that antimicrobial resistance is one of the top 10 threats to global public health.
A researcher holding a petri dish at the microbiology lab of the Universitair Ziekenhuis Antwerpen in 2010 after a man died in Belgium following infection by a superbug, NDM-1, that is resistant to almost every antibiotic. (Jorge Dirkx/AFP/Getty Images)

Performing the Treatment

Awad said that the photodynamic technology used in this treatment works differently from antibiotics, harnessing light energy to generate highly reactive oxygen molecules. These highly reactive oxygen molecules destroy microbial cells and kill deadly bacteria without harming human cells.

Senior researcher at UniSA, Prof. Clive Prestidge, said that the new therapy is created in oil and is painted on a wound as a lotion.

“When laser light is applied to the lotion, it creates reactive oxygen species which act as an alternative to conventional antibiotics,” he said.

“The term oil used is for simplification,” said Awad in an email to The Epoch Times. “The more precise term is nanocarriers made up of food grade oils.”

Awad said that this study used a LED blue light lamp, the fluence—the energy of laser pulse per unit area illuminated—which varied depending on the target bacteria. He said that further details on the laser are mentioned in the research team’s published articles.
A laser tests the optical waveguide of a chip for quantum computing in a laboratory in Stuttgart, southern Germany, on Sept. 14, 2021. (Thomas Kienzle/AFP via Getty Images)
A laser tests the optical waveguide of a chip for quantum computing in a laboratory in Stuttgart, southern Germany, on Sept. 14, 2021. Thomas Kienzle/AFP via Getty Images

Treatment Advantages

Prestidge said that this new therapy has some key advantages over conventional antibiotics and other light therapies. He said that current photoactive compounds suffer from poor solubility in water, which limits their clinical application.

“Our approach uses food-grade lipids to construct nanocarriers for the photoactive compound, which improves its solubility and antibacterial efficiency far beyond that of an unformulated compound.

Awad said that employing nanocarriers to improve the solubility of the photoactive compound used in this treatment, gallium protoporphyrin (GaPP), permits the compound’s interaction with light and oxygen. He said that it also improves the antibacterial efficiency of gallium protoporphyrin by delivering it into bacterial communities known as biofilms.

“These molecules target multiple bacterial cells at once, preventing bacteria from adapting and becoming resistant. So, it’s a far more effective and robust treatment,” Prestidge said.

Bottles of antibiotics line a shelf at a Publix Supermarket pharmacy in Miami, Fla., on Aug. 7, 2007. (Joe Raedle/Getty Images)
Bottles of antibiotics line a shelf at a Publix Supermarket pharmacy in Miami, Fla., on Aug. 7, 2007. Joe Raedle/Getty Images

Safety of the Treatment

Awad said that the safety of the treatment was tested on a defined population of human cells as well as in animal models, and the produced ROS showed a positive safety profile in both models.

“Importantly, the human skin cells involved in the wound healing process showed enhanced viability, while the antibiotic-resistant bacteria were entirely eradicated,” Prof. Prestidge said.

“The lifetime of produced ROS is estimated in microseconds, and their production ceases once the light is switched off,” Awad said.

Awad added that further investigations are ongoing to ensure the safety of this technology.

A Scientist looks at cells through a fluorescent microscope at the laboratories at Cancer Research U.K. Cambridge Institute, in Cambridge, England, on Dec. 9, 2014. (Dan Kitwood/Getty Images/Cancer Research U.K.)
A Scientist looks at cells through a fluorescent microscope at the laboratories at Cancer Research U.K. Cambridge Institute, in Cambridge, England, on Dec. 9, 2014. Dan Kitwood/Getty Images/Cancer Research U.K.

Highly Reactive Oxygen Species

Awad said that the principle of the reaction depends on using gallium protoporphyrin as an antenna molecule that transfers the energy of light to molecular oxygen —the oxygen that we breathe.

He said that upon this energy transfer, the non-active oxygen molecules are activated into highly reactive oxygen species that can disrupt bacterial membranes and kill them.

Awad said that immune cells do produce reactive oxygen species (ROS) as a defence mechanism, but this technology produces higher amounts of ROS that targets localized infection.

“In addition, the major challenge to antibiotics and immune cells is biofilms, i.e. sessile mode of growth of bacteria, where they attach to surfaces and produce protective slime of extracellular matrix.”

“This matrix prevents antibiotics and immune cells from reaching the embedded bacteria.”

However, Awad said that this treatment successfully disrupted the biofilm matrix and killed embedded bacteria without harming human cells.

Lily Kelly
Lily Kelly
Author
Lily Kelly is an Australian based reporter for The Epoch Times, she covers social issues, renewable energy, the environment and health and science.
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