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Issue: 59 - Nov 15, 2013
MRSA: A New Zoonotic Threat?
By: By: Chery F. Kendrick, DVM, MPVM, MLT, CFS
Kendrick Technical Services, LLC

We see a lot in the news these days about MRSA, defined by the CDC (Centers for Disease Control) as:

“Methicillin-resistant Staphylococcus aureus, a type of staph bacteria that is resistant to many antibiotics”

So when an announcement came across my desk that “MRS is up 30% in dogs” I took special care to read the alert, and carefully analyze the data to see what I needed to include in my ‘Updates on Zoonosis’ OSHA Training.

What I found was indeed interesting, and I have included this information in the updated zoonotic training for our clinics and clients, however I am relieved that the facts do Not warrant the level of concern elicited at first reading.

Here are the facts:

  1. MRS (Methicillin Resistant Staph) infections in dogs and cats are indeed increasing. According to local dermatology specialist Keith A. Hnilica DVM,MS,DACVD there has been a 30% increase in MRS infections
  2. The MRS seen in these animals however is NOT MRSA but rather two other families of Staph namely MRStaph pseudintermedius (MRSP) and MRStaph schleferi (MRSS)
  3. While both are indeed equally zoonotic and are indeed Methicillin resistant they do Not pose the zoonotic hazard of the MRS aureus type.

Let’s look at two critical issues here:

1)  MRSP is no more likely to cause a post-surgical infection than methicillin-susceptible S. pseudintermedius.  It's just harder to kill when an infection occurs.

2)  Methicillin-susceptible S. pseudintermedius can be found on almost all dogs.

So why all the confusion? Is there a need for concern?

The reason for confusion lies in the simple fact of misinformation, a lack of education in simple microbiology.

This is fueled by the media’s reporting without fact checking or educating.

A great example of misinformation and resulting panic was in the story that spread like wild fire this past June 2013. That story arose from a disgruntled ex-shelter worker in Miami FL reporting to the media that they had “an outbreak of MRSA virus”. This story that was reported by local media then went national was a great example of misinformation especially the confusion regarding “virus” isolation.

(I can feel you all sighing and nodding your heads in this, our constant struggle to educate the public on the difference between bacteria and virus).

What was especially sad were that the quotes by a veterinarian and director were equally confusing to say the least and the resulting stories that emerged were egregiously inaccurate.

The story originated from the disgruntled ex-employee and was blown up by an overly aggressive reporter who did not take the time to research the issue himself, educate himself on the facts underlying the story- instead he did what so many do today- run with the sensational- Facts be damned!

(No there was no MRSA, yes there was a disgruntled ex-employee, yes the director and veterinarian panicked when approached by the media and no the news station Never clarified but simply allowed misinformation to spew.)

This media circus was a great example of why it is critical to educate- of course we begin with our staff and they in turn help us to educate our clients.

The critical area of discussion should begin with a review of the difference between species of bacteria, the simple biology of antibiotic susceptibility and resistance and the fact that most people (and animals) are totally unaffected by MRS of any species.

30% of humans and animals carry staph species on them and 1% of humans carry Staph aureus with NO harmful effect

Staph aureus is mainly a problem in immunocompromised patients. MRSA in dogs is a concern because it is an important cause of infection in both people and animals however it is an opportunist, meaning it typically does Not cause disease in normal healthy people and animals. In fact most are regularly exposed to MRSA and less than 1% of those exposures result in infections.

While we need to right balance in the discussion of MRS it is also a good time to remind our staff that THIS is exactly why we have the infectious disease protocol in place, to protect our patients as well as our staff from pathogens. It is always good to also take his opportunity to educate our clients on the measures we take to ensure the safety of their pet while in our facility as well as our concern for their whole family’s health.

Remember we play a role as educators in the community especially in regards to zoonotic diseases.

And an important part of that education for both staff and public should include basics on different species and potential zoonotic risk. According to infectious disease control specialist Dr. Scott Weese: “the first thing I ask is what staph species was isolated? Most often it is Staph pseudintermedius or another staph. While these are still relevant they do NOT carry the same human health risk as MRSA.”

Now be sure to remind your staff during their zoonotic training that every dog is carrying lots of different bacteria that cause infection at any time. This is why we have the antisepsis protocol in place – clipping, scrubbing, sterile instruments, properly cleaned surgical suite and properly gowned and gloved techs and surgeons. This is also why we glove up when treating skin infections. But as for the doom and gloom zoonotic risk- it simply is not warranted.

Here are some good references for you to use for your staff zoonotic updates:

Be sure to share with your staff these awesome articles on Staph in animals:

Stay safe out there- and stay informed!


Be sure to come by our booth at the Virtual Trade Show Tuesday and Wednesday the 12th and 13th of November and say “Hi”! Also ask about our New OSHA GHS/Labeling and SDS training! The ONLY Veterinary specific GHS training available!

Chery F. Kendrick, DVM, MPVM, MLT, CFS is a writer, educator, speaker and consultant. She is the nation’s leading veterinary regulatory control and OSHA expert. Her time spent in Washington D.C. as an advocate for the veterinary profession with OSHA and other regulatory agencies has resulted in many positive compliance changes for our industry. She has the only manuals and training programs are used by clinics and animal care facilities nationwide. She speaks at association meetings and conferences nationwide. Her well attended workshops are constantly praised as powerful resources for practice managers, veterinarians and their staffs.

Please feel free to contact her at  with your questions and visit her web site at

For information on Dr. Kendrick’s workshops and workbooks or OSHA onsite consulting services please contact her at Kendrick Veterinary Consulting Group, LLC 865-405-4255 or