13 June 2011

New strain of MRSA discovered in UK dairy cows

Need another reason not to drink cow's milk? A new strain of methicillin-resistent Staphylococcus aureus (MRSA) has been detected in dairy cows.

A study led by Dr. Mark Holmes, from the University of Cambridge, found the new strain in dairy cows while he was studying S. aureus, a bacterium that causes infection in cows' udders. It is undetectable using the normal tests because of its genetic makeup, which differs from other strains.

Dr. Laura García-Álvarez, also involved in the study, discovered the new strain while pursuing her PhD at the University of Cambridge Veterinary School. She said, "To find the same new strain in both humans and cows is certainly worrying. However, pasteurization of milk will prevent any risk of infection via the food chain. Workers on dairy farms may be at higher risk of carrying MRSA, but we do not yet know if this translates into a higher risk of infection. In the wider UK community, less than 1% of individuals carry MRSA – typically in their noses – without becoming ill."

Tests have revealed that not only is this strain present in cows, it's also present in humans. Samples from residents living in European countries showed the existence of the new strain.

"This situation boils down to the question of whether humans are infecting cows or cows are infecting humans, said Holmes. "...it does appear that the numbers are rising. The next step will be to explore how prevalent the new strain actually is and to track where it is coming from. If we are ever going to address the problem with MRSA, we need to determine its origins."

Geanna Marek | @greenvegnliving
Geanna has been a vegan for over 3 years. She lives in the very veg-friendly city of Portland, Oregon, where she works as a freelance writer and library assistant. She is also currently training to run the Portland Marathon this fall. In her spare time, she enjoys spending time outdoors, reading, eating, and traveling. Find Geanna at greenveganliving.com.

Photo Credit: cc: flickr.com/photos/jahnke_adam