MRSA Infections in Horses and Other Animals

Infections caused by methicillin-resistant Staphylococcus aureus, or MRSA, were found in horses, cats, and dogs included in a recent study in Germany. Between 2010 and 2013, researchers checked more than 5,200 swabs from infected wounds treated at 1,170 veterinary facilities. Out of 604 swabs from horses, those from 138 equines (23%) showed the presence of S. aureus. Swabs positive for S. aureus were also taken from 6% of the dogs and 12% of the cats in the study.

S. aureus bacteria are widespread in the environment, but not all S. aureus are of the MRSA strain. MRSA was identified in 63% percent of the relevant dog swabs, 46% of the cat swabs, and 41% of the equine swabs. Human-associated MRSA strains were most common in the infections in dogs and cats in the study, while nearly 90% of the equine MRSA was identified as the CC398 lineage. Previous to this study, horses with MRSA were most often infected with the CC8 lineage.

The researchers suggested that further studies in both humans and animals could trace the sources of MRSA infections, enabling better risk assessment and possibly leading to ways to limit the spread of the MRSA strains. Scientists from the Free University Berlin, IDEXX Laboratories, and the Department of Infectious Diseases Epidemiology at the Robert Koch Institute in Berlin cooperated in the study.