A new form of drug-resistant Staphylococcus aureus (MRSA) has been found in dairy cows and humans in the U.K. and Denmark, providing more evidence that animals could be passing this superbug on to people-not just the other way around.
The new methicillin-resistant bacterial strain was found in tests of raw milk by a team looking for another infection among the herds. Pasteurization kills off the bacteria, making milk products-even from a cow infected with this antibiotic-resistant strain-safe for consumers, the researchers explain.
But one thing does trouble scientists: this new strain would be missed by the newest types of MRSA testing because it contains a new variant of the known resistance gene. These genetic tests have, until now, been considered the new gold standard of detection and are now widely used in many hospitals in continental Europe.
"Those DNA tests, they all missed this," says Tara Smith, an assistant professor of epidemiology at the University of Iowa. "The gene they were looking for wasn't there."