A new strain of methicillin-resistant Staphylococcus aureus, or MRSA, has turned up in European dairy cows and some humans. Researchers first detected the novel MRSA strain in the United Kingdom, but the bacterium was subsequently found in Denmark, Germany and Ireland as well, according to Science. Scientists identified the new strain by noting that samples containing it were resistant to antibiotics normally fatal to S. aureus. But PCR could not detect a gene, mecA, commonly used to confirm the presence of MRSA. That was due to the fact that the new strain of MRSA contained a new mecA variant that eluded the PCR test. Although the same MRSA strain and mecA variant have been identified in both humans and cows, it is not likely pose a public health risk because pasteurization of infected milk completely kills any MRSA present. The people most likely to be infected with the strain found in cows are farm workers in close contact with the animals, the authors of The Lancet Infectious Diseases paper announcing the discovery of the new strain told Science. Read the Antimicrobial Agents and Chemotherapy paper reporting the presence of the new mecA variant in samples taken from patients in Irish hospitals here.