AUG 20, 2016 3:48 AM PDT

Salt Discovery Could Prevent Food Poisoning from MRSA

Can the staph superbug, also known as MRSA, be brought down by salt? Scientists finally expose a key weakness in these bacteria that makes them susceptible to dehydration from high salt concentration. And this could mean an antibiotic-free alternative to thwarting this superbug.

The formidable methicillin-resistant Staphylococcus aureus (MRSA) bacteria account for over 80,000 hospital-acquired infections, leading to over 11,000 deaths every year. MRSA infections take a serious turn when the bacteria invade the bloodstream and major organs, and antibiotics available in doctors’ arsenals can’t seem to contain them. This is the case with some MRSA strains, which have developed resistance to vancomycin, one of the most valuable antibiotics against staph infections.
To explore other ways to target staph bacteria, scientists at the Imperial College London looked at how the bacteria regulate its salt balance, since high salt can cause cells to lose water and die. They found that S. aureus is notoriously good at protecting itself against dehydration via a signaling molecule known as cyclic di-AMP. Targeting this signaling molecule appeared to break the bacteria’s defenses against water loss, making it more susceptible to high salt concentrations.

"The Staphylococcus aureus bacterium is a key pathogen and causes many serious infections in patients. With this research we now have a better understanding of how the bacteria cope with salt stress. Although this research is at an early stage, we hope this knowledge will someday help us to prevent food borne staphylococcal infections, as well as open new possibilities for a type of treatment that may work alongside antibiotics,” said Angelika Gründling, senior author of the study.

The research findings could have direct health impacts through the foods we eat. "Many food preservation methods use salt to keep food fresh and prevent bacteria from multiplying. However, there are always some bacteria such as Staphylococcus aureus that are resistant to these high salt levels, and survive,” said Christopher Schuster, the study’s first author.
Indeed, food poisoning from lingering staph bacteria is all too common. “But if we can develop some form of treatment that interrupts these signaling molecules, we could ensure salt kills all of the bacteria,” Schuster explained.
This mechanism may even apply more broadly to other bacteria. In experiments, other researchers have also shown that Listeria bacteria also use a similar coping mechanism. 

Additional source: Imperial College London
About the Author
Doctorate (PhD)
I am a human geneticist, passionate about telling stories to make science more engaging and approachable. Find more of my writing at the Hopkins BioMedical Odyssey blog and at
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