A shared population of methicillin-resistant Staphylococcus aureus (MRSA) bacteria circulates both in humans and companion animals, according to a study published this week in mBio®, the online open-access journal of the American Society for Microbiology.
"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 in England. 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 United Kingdom.
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 United Kingdom 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 English 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 United Kingdom.
Holmes says pet owners don't need to worry.
"MRSA infection in cats and dogs is still extremely rare," Holmes says. "There is very little risk of owners getting ill from their pets." In addition, he says, healthy pets are not likely to pick up MRSA from their human companions but if a pet already is ill or its health is severely compromised, MRSA patients should inform their pets' veterinarians.
The study was supported by a Medical Research Council Partnership grant held between the Department of Veterinary Medicine and the School of Clinical Medicine at the University of Cambridge, the Moredun Research Institute and the Wellcome Trust Sanger Institute.
mBio® is an open access online journal published by the American Society for Microbiology to make microbiology research broadly accessible. The focus of the journal is on rapid publication of cutting-edge research spanning the entire spectrum of microbiology and related fields. It can be found online at http://mbio.asm.org.
The American Society for Microbiology is the largest single life science society, composed of over 39,000 scientists and health professionals. ASM's mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.
Jim Sliwa | Eurek Alert!
Understanding a missing link in how antidepressants work
25.11.2015 | Max Planck Institute of Psychiatry, München
Plant Defense as a Biotech Tool
25.11.2015 | Austrian Centre of Industrial Biotechnology (ACIB)
The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...
Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.
In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...
In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.
Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...
Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a...
AWI researchers’ unique 15-year observation series reveals how sensitive marine ecosystems in polar regions are to change
The warming of arctic waters in the wake of climate change is likely to produce radical changes in the marine habitats of the High North. This is indicated by...
25.11.2015 | Event News
17.11.2015 | Event News
21.10.2015 | Event News
25.11.2015 | Agricultural and Forestry Science
25.11.2015 | Earth Sciences
25.11.2015 | Physics and Astronomy