New research from the U.K. supports the theory that antibiotic-resistant bacteria in livestock can be transmitted to humans. Scientists at the University of Edinburgh studied the evolutionary history of methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 398 (CC398), mapping the full genetic code of the strains from the U.K. and comparing them with published genetic data on CC398 bacteria from humans and livestock around the world. Although people and animals generally carry distinct variants of CC398, the researchers found multiple instances of transmission from livestock to humans and from country to country. In particular, they found the livestock-associated strain in isolates from hospitals and newborn babies. In addressing the use of antibiotics on farms, the researchers wrote that their analysis “revealed significant differences in the dynamics of resistance to methicillin and tetracycline related to contrasting historical patterns of antibiotic usage between the livestock industry and human medicine.” The study was funded by the European Commission Framework Programme 7, the Biotechnology and Biological Sciences Research Council, the Wellcome Trust, the Scottish Universities Life Sciences Alliance, Pfizer and the Medical Research Council.