Researchers have discovered how bacteria commonly found in hospitals spread using ‘nano-weapons,’ providing valuable insights in the battle against antibiotic-resistant superbugs. The study, led by the Monash Biomedicine Discovery Institute (BDI) and published in Nature Communications, focused on the hospital bacterium Acinetobacter baumannii.
Acinetobacter baumannii (A. baumannii) is a highly opportunistic bacterium known for infecting individuals already suffering from conditions such as pneumonia, urinary tract infections, or wounds. It can colonize the lungs and cause infections in the body’s organs or on the skin. Its ability to survive on dry surfaces for up to a month, along with its presence on the skin of healthcare workers, contributes to its high transmissibility.
Furthermore, its resistance to common antibiotics makes infections difficult to treat. As a result, the World Health Organization has classified it as a top-priority critical bacterium, emphasizing the urgent need for new treatments.
Researchers at Monash University have made a significant discovery in the fight against harmful bacteria. Their study revealed that A. baumannii is able to outcompete other bacteria by employing a needle-like nano “machine” to inject deadly toxins into nearby bacteria. This discovery opens the door to new strategies for combating these harmful germs.
“We learned how this toxin, called Tse15, is attached to the needle and then delivered to other bacteria to kill them. We showed that the toxin is stored in a protective cage-like structure inside A. baumannii, preventing it from harming the bacterium itself. When ready to attack other bacteria, the toxin must be released from the cage,” said study co-first author Brooke Hayes.
“This happens through a series of interactions between the toxin, the exterior of the cage, and the T6SS needle. Once the needle injects the toxin into a competitor, the toxin activates and kills the other bacterium, allowing A. baumannii to take over that surface.”
Now that scientists have unlocked the secrets of A. baumannii’s weaponry, they believe they can discover ways to combat the bacteria and potentially harness them for beneficial purposes. Understanding how to disable its weapon system could lead to more effective methods of eliminating it. Moreover, researchers suggest that they might also be able to modify the bacteria to deliver different toxins to neighboring bacteria, enlisting them in the fight against other harmful invaders.
This breakthrough would complement other strategies in development to combat superbugs, such as using a molecular wedge to make them vulnerable to antibiotics, employing mechanical destruction methods to thwart their ability to evolve, and utilizing a combination approach to overwhelm disease-causing bacteria and prevent them from defending themselves.
Journal reference:
- Brooke K. Hayes, Marina Harper, Hariprasad Venugopal, Jessica M. Lewis, Amy Wright, Han-Chung Lee, Joel R. Steele, David L. Steer, Ralf B. Schittenhelm, John D. Boyce & Sheena McGowan. Structure of a Rhs effector clade domain provides mechanistic insights into type VI secretion system toxin delivery. Nature Communications, 2024; DOI: 10.1038/s41467-024-52950-x