New MRSA 'superbug' discovered in cows, humans

The new MRSA strain, according to the scientists, is immune to antibiotics and is impossible to detect with the standard tests performed in hospitals due to its unusual genetic make-up.

Researchers from Cambridge University have stumbled on the new microorganism while studying bovine mastitis, a fatal bacterial infection observed in dairy cows.

The research lead and a senior lecturer in preventive veterinary medicine at Cambridge University, Mark Holmes, stated that the unseen variant "potentially poses a public health problem."

Discovery is worrying but infection risk is low
Scientists conducted a study with 940 samples for mastitis, and discovered the MRSA bacteria in 13 of the samples.

They also conducted tests on people who were treated for MRSA, and observed the same bacteria in subjects from Scotland, England, and Denmark.

Standard molecular test detects the mecA gene present in the normal MRSA bacteria but failed to identify the new strain as its mecA gene has only 60 percent similarity.

Dr Laura Garcia-Alvarez, who first discovered the strain during her Ph.D. study at the university, said, “To find the same new strain in both humans and cows is certainly worrying.”

She added, ''However, pasteurization of milk will prevent any risk of infection via the food chain.”

Future study to find the source
Garcia-Alvarez said, ''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.”

Holmes added, "Although there is circumstantial evidence that dairy cows are providing a reservoir of infection, it is still not known for certain if cows are infecting people, or people are infecting cows. This is one of the many things we will be looking into next."

''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,'' Holmes said.

The findings have been published in the journal ‘The Lancet Infectious Diseases.’