HAMILTON, Ontario — The key to beating deadly antibiotic-resistant bacteria may be a toxin coming from a very unlikely source — pneumonia.
The discovery by researchers from McMaster University opens the door to a generation of more effective antibiotics. Estimates predict that 10 million people will die of untreatable infections by 2050 unless more effective drugs are available.
Pseudomonas aeruginosa is a pathogen that causes hospital-acquired infections, including pneumonia. It contains a compound that has evolved to destroy other microbes, including species too strong for normal medication. The crucial aspect of this toxin is its mechanism, according to lead author John Whitney.
“This research is significant, because it shows that the toxin targets essential RNA molecules of other bacteria, effectively rendering them non-functional,” says Whitney, associate professor for the Department of Biochemistry and Biomedical Sciences, in a media release.
“Like humans, bacteria require properly functioning RNA in order to live.”
It has structural similarities to DNA, turning genetic information into proteins.
“It’s a total assault on the cell because of how many essential pathways depend on functional RNAs” adds first study author Nathan Bullen, a graduate student in McMaster’s Department of Biochemistry and Biomedical Sciences.
“This toxin enters its target, hijacks an essential molecule needed for life, and then uses that molecule to disrupt normal processes.”
Superbugs a ‘threat to mankind’
Researchers identified its three-dimensional shape by examining crystals of the purified toxin under a state-of-the-art scanner at McMaster. The Canadian team have been working with colleagues at Imperial College London for nearly three years to understand exactly how the toxin functions at a molecular level.
Rigorous experimentation on common targets such as proteins and DNA molecules led to testing it against RNA. The breakthrough shatters well-established precedents set by toxins secreted by other bacteria, such as those that cause cholera and diphtheria.
The study, published in the journal Molecular Cell, reveals that it holds great potential for solving the infectious diseases crisis — described by the World Health Organization as “one of the biggest threats to mankind.”
Currently, superbugs cause an estimated 700,000 deaths annually, a figure set to soar almost by nearly 15 times over the next three decades. Over-prescribing medication, people not taking antibiotics properly, and farmers feeding antibiotics to animals are all among the suspects factors which are making medicines weaker.
Part of the problem is the ability of bugs to evolve after exposure to small amounts of antibiotics. They learn how to survive these attacks. The new compound’s “mode” of activity can help future antibiotics, as it kills bacteria in a different way, Prof. Whitney concludes.
South West News Service writer Mark Waghorn contributed to this report.
