Parasites of viruses drive superbug evolution
Published: 04 Aug 2023
Assistant Professor John Chen from the Department of Microbiology and Immunology and the Infectious Diseases Translational Research Programme at the NUS Yong Loo Lin School of Medicine (NUS Medicine), and lead researcher of the study, observing the exchange of dangerous genes by a deadly pathogen, Staphylococcus aureus.
In a study published today in Cell, one of the most prominent peer-reviewed scientific journals in the field of Biochemistry & Molecular Biology, scientists from the National University of Singapore (NUS) and Imperial College London have discovered a new way by which bacteria transmit their genes, enabling them to evolve much faster than previously understood.
Led by Assistant Professor John Chen from the Department of Microbiology and Immunology and the Infectious Diseases Translational Research Programme at the NUS Yong Loo Lin School of Medicine (NUS Medicine), the insights could help scientists to better understand how pathogenic bacteria evolve and become increasingly virulent and resistant to antibiotics.
The ability to share genetic material is the major driver of microbial evolution because it can transform a benign bacterium into a deadly pathogen in an instant. Phages, the viruses of bacteria, can act as conduits that allow genes to transfer from one bacterium to another by a process known as genetic transduction.
The new process is termed lateral cotransduction, and the architects behind this new frequency and speed in bacterial evolution are the Staphylococcus aureus pathogenicity islands (SaPIs), which are selfish DNA elements that exploit and parasitise phages and are commonly found integrated into the chromosomes of S. aureus isolates. S. aureus is a type of bacteria that can cause Staph infections in humans and animals. SaPIs are significantly more potent and efficient in transmitting bacterial genes.
Prof Chng Wee Joo, Vice-Dean (Research) at NUS Medicine, said, “This groundbreaking discovery will impact the way we understand how bacteria evolves through gene transfer, and their potential implications on bacterial infections and diseases. This research is also paramount in informing safe treatment decisions in clinical settings, and it is an absolute honour to have our work published in this prestigious journal.”
The rise of superbugs has called for new ways to treat antibiotic-resistant strains. Phage therapy involves the use of phages to eliminate harmful bacteria in infections and diseases. However, instead of just fighting bacteria, some therapeutic phages could turn out to be the unwitting accomplices of SaPIs or other related elements capable of lateral cotransduction.
“They (phages) could be used to destroy bacteria in the short term but end up spreading harmful genes to other cells in the long term, which could prove to be disastrous. With this new way of understanding the evolutionary mechanisms of disease-causing organisms, it is important for therapeutic phages to be carefully vetted before they are used for therapy,” said Asst Prof Chen.
Read more in the press release here.
