MRSA Strain Associated with Pigs Adapts to Humans

Methicillin-resistant Staphylococcus aureus (MRSA) clonal-complex (CC) 398 is the dominant MRSA in European livestock and a growing cause of human infections. A new study fully characterizes the evolutionary dynamics of the mobile genetic elements—agents of horizontal gene transfer—whose presence or absence distinguishes CC398 from a closely related and less antibiotic-resistant human-associated population. To do this, the researchers used a collection of 1180 CC398 genomes, sampled from livestock and humans, over 27 years.