Infectious bacteria using milk protein to survive in cows
The bacteria is able to release nutrients from cows' udders.
An infectious bacteria has adapted to using a milk protein to survive and persist in dairy cows.
Researchers from the Roslin Institute discovered that Staphylococcus aureus has gone through metabolic changes to release nutrients in cows’ udders.
The bacteria, a widespread cause of human disease, is also a leading cause of mastitis in dairy cows. When moving from humans into cattle, it is evolving new ways to get nutrients from cow milk.
Researchers have used genetic analysis of bacterial strains from affected people and cattle to assess how it is making the transition to cattle.
The bacteria has been found to evolve an enhanced ability to break down casein, which is the most abundant protein in milk. This is allowing the bacteria to thrive in the udder while accessing nutrients to support growth.
It achieves this through an increased expression of aureolysin, a bacterial enzyme which breaks the casein to fragments. These fragments are then used as nutrients for growth during infection.
This strategy has developed in several bovine strains of S. aureus. This strong evolutionary pressure is helping the bacteria adapt to multiple environments and species.
It is hoped that these findings will suggest new potential ways to control mastitis in dairy cattle and target pathways that will are important to growth.
Amy Pickering, BBSRC fellow at the Roslin Institute, said: “Understanding how pathogens adapt after jumping between species is crucial for tackling infectious disease. Our research provides a clear example of how genetic changes can promote the successful transition to a new species.”
Ross Fitzgerald, professor of molecular bacteriology, added: “By understanding the mechanisms underpinning successful host-adaptation, we can start to think about novel ways to control infection. These findings provide insights into where future treatments could intervene.”
The full study can be found in the journal Science Advances.
Image © Shutterstock.com/ Clara Bastian
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