New blog on animal health including MRSA

Dr. J. Scott Weese of the Ontario Veterinary College (author of many important papers, discussed in many posts here, on MRSA in food and companion animals) has started a blog on animal-health issues. Here is a recent post on tracking down the source of a MRSA infection when there is a pet in the house.

The blog is called Worms and Germs and I've added it to the blogroll at right.

Much more on MRSA and animals

Again from the 108th General Meeting of the American Society for Microbiology: new findings on the complex interaction of MRSA in humans, pets and food animals.

• From the University of Iowa, the first finding of MRSA in US pigs, on seven farms in Iowa and Illinois. The abstract doesn't say what subtype of MRSA was found, but a new strain of MRSA was found last year in pigs in the Netherlands and both that strain and a known human strain have been found in pigs in Canada. Carriage rates among the Midwestern pigs: from 100% of very young animals to 36% among adult swine. (Poster 983, first author AL Harper)
• From Nicholls State University and two veterinary practices in southern Louisiana, results of screening tests on pets show high rates of carriage of methicillin-resistant Staph species. The pets carried both S. aureus and S. intermedius. (Poster 1017, first author T. Rachal.) For an earlier post on pets harboring MRSA, look here.
• And from the University of Georgia, an analysis of MRSA strains isolated from 50 humans and 60 companion animals (dogs, cats, horses, birds) found the same strains in both: SCCmec type II, a hospital strain, and SCCmec type IV, the main community strain. Human carriage rates: 78% type IV, 22% type II. Animal carriage rates: overall, 40% type IV and 60% type II, but with some important differences between species — all of the cats and birds harbored type II, while the dog isolates were overwhelmingly II and the horses overwhelmingly IV. Of greatest importance, the types did not have identical resistance patterns: In humans, the type IV was sensitive to vancomycin and tetracycline, but the animal IV was sensitive to vanco only, suggesting that MRSA may be evolving differently in its transient animal hosts — an especial concern if the animal-carried strains pass back to humans. (Poster 1027, first author S. Sanchez.)

MRSA and animals and hospitals

I am at the annual meeting of the Association of Health Care Journalists, where last night we heard actor Dennis Quaid discuss the severe medical error that led to his infant twins being given 1000x the appropriate dose of heparin - twice. (Interesting tidbit: The twins were in the hospital because of a staph infection.) Quaid and his wife have set up a foundation that will work to reduce medical errors and is soliciting stories from victims and families.

Later today I'll be moderating a panel on mandatory reporting of hospital infections that we hope will provoke an, ahem, free and frank exchange of views. More on that to come.

Meanwhile, though, a wrinkle in the possibility that companion animals might spread MRSA: What if they are therapy animals?

An international collaborative group has contemplated that question and come out with a thoughtful set of guidelines that are published in this month's issue of the American Journal of Infection Control. The guidelines address both official therapy animals and also pets who live in long-term care facilities or are brought to visit patients.

Key considerations: Animals could not only spread disease to patients because they are colonized; they may also become colonized because they are handled by patients. Because transmission and colonization may be so dynamic, the most important preventive measure will be hand hygiene rather than attempting to evaluate the animal's bacterial carriage at any single point. And key points: To minimize opportunities for transmission, exclude animals that have come directly from a shelter or pound; animals that eat a raw-food diet; animals that haven't been or can't be housebroken or litter-trained.

The guidelines are here, and there's a good MSM summary by Helen Branswell of the Canadian Press here.

More on pets and staph

I am at the International Conference on Emerging Infectious Diseases, a biannual meeting sponsored by the CDC that is a disease geek's dream of heaven. The days are extremely packed — about 2,000 attendees and presentations every 15 minutes for most of three days — so blogging may be a little light. Lots of MRSA news here though, so there will be a lot to catch up on.

Here's one example: Engeline Van Duijkeren of Utrecht University reported this afternoon on an outbreak of Staphylococcus intermedius, a staph species that colonizes and causes disease in dogs and cats but is rarely found in humans. Between late 2006 and early 2007, the lab at Utrecht received samples for analysis from six animals, all of which had surgery at the same veterinary hospital: five dogs with orthopedic surgery, one cat with abdominal surgery. The samples yielded identical strains of S. intermedius that were all methicillin-resistant — and resistant to a host of other drugs as well, from 3d and 4th generation cephalosporins to clindamycin to tetracycline to Bactrim.

The lab group found the case cluster and the resistance pattern so striking that they looked around for a common source, including among the clinic's veterinary personnel. They swabbed the surgeon, six technicians, two healthy dogs who lived in the clinic, and the local environment. They found the identical strain in the noses of the surgeon, three of the technicians, and one of the house dogs. Conclusion, van Duijkeren said: The humans (who were colonized, not sick) picked up the strain and redistributed it to the animals under their care. It's the first recorded transmission of MRSI between humans and animals.

(Worth noting: A questioner from the University of Pennsylvania, which has done a lot of work on staph in animals, rose during the Q/A to suggest that the hospital was experiencing a clonal cluster of cases that arose independently, rather than a chain of transmission. Oooh, more fodder.)