Cookies on VetMed Resource

Like most websites we use cookies. This is to ensure that we give you the best experience possible.

Continuing to use www.cabi.org means you agree to our use of cookies. If you would like to, you can learn more about the cookies we use.

News Article

Humans and companion animals share MRSA isolates from the same population

Companion animals may act as a reservoir for human MRSA infection and vice versa.

A shared population of methicillin-resistant Staphylococcus aureus (MRSA) bacteria circulates in humans and companion animals, according to a study published in mBio.

"Our study demonstrates that humans and companion animals readily exchange and share MRSA bacteria from the same population," says senior author Mark Holmes, senior lecturer in preventive veterinary medicine at the University of Cambridge, UK. MRSA naturally lives on the skin and also causes difficult-to-treat infections in humans and animals. "It also furthers the 'one health' view of infectious diseases that the pathogens infecting both humans and animals are intrinsically linked, and provides evidence that antibiotic usage in animal medicine is shaping the population of a major human pathogen."

Holmes and colleagues sequenced the genomes of 46 MRSA samples from cats and dogs, collected between August 2003 and August 2007 from two large veterinary hospitals and several smaller veterinary practices throughout the UK. The samples were found to be similar to those associated with MRSA strains in humans, with most coming from wound infections or skin and soft tissue infections. Additional samples were from the animals' urine; cerebrospinal fluid; nasal wash or discharge; and bloodstream, heart valve or joint infections.

Comparing the samples to a global collection of human MRSA samples sequenced as part of other studies and evaluating the evolution of the bacteria, the investigators found that all animal infections fell in the same family: Epidemic MRSA 15 (EMRSA-15) (sequence type ST22), a common strain of MRSA first detected in the UK in the 1990s that spread throughout Europe. The bacteria were interspersed throughout the EMRSA-15 genetic family tree. Nearly all samples were genetically similar to human bacteria, and their place in the family tree showed that the companion animal bacteria most likely originated in humans.

Researchers also observed that samples from the same veterinary hospitals clustered together genetically, suggesting that as in human hospitals, MRSA can be readily transmitted in veterinary hospital settings.

"It's a reminder that constant vigilance and high levels of hygiene are just as important when treating cats and dogs as with humans," Holmes says.

Analysis of the genomes showed very little genetic discrimination between bacteria samples from humans and animals, indicating that the MRSA from cats and dogs had not undergone extensive adaptation to the companion animals, suggesting this type of MRSA has a broad host range. But the animal MRSA were significantly less likely than those from humans to have resistance to the antibiotic erythromycin, used rarely in UK veterinary practices. Instead, these MRSA from animals were more likely to contain mutations making them resistant to the antibiotic clindamycin, used widely in veterinary medicine in the UK.

Read article: A Shared Population of Epidemic Methicillin-Resistant Staphylococcus aureus 15 Circulates in Humans and Companion Animals by Ewan M. Harrison, Lucy A. Weinert, Matthew T. G. Holden, John J. Welch, Katherine Wilson, Fiona J. E. Morgan, Simon R. Harris, Anette Loeffler, Amanda K. Boag, Sharon J. Peacock, Gavin K. Paterson, Andrew S. Waller, Julian Parkhill and Mark A. Holmes, published in mBio (2014) vol. 5 no. 3 e00985-13, doi: 10.1128/mBio.00985-13

Article details

  • Date
  • 14 May 2014
  • Source
  • American Society for Microbiology
  • Subject(s)
  • Dogs, Cats, and other Companion Animals