Does My Dog Have MRSA? Is it contagious?

Canine Skin Solutions, Inc.                    Karen Helton Rhodes, DVM, DACVD

www.HealthySkin4Dogs.com        Terri Bonenberger, DVM, DACVD

Does My Dog Have MRSA?  Is it contagious?

Ok, let’s talk about resistant bacterial infections (methicillin resistant staphylococcus infections) in your dog.  First and foremost, DON’T PANIC!

MRSA vs. MRSP:  MRSA (methicillin resistant staphylococcus aureus) is the bacterium commonly found in people.  Not the dog.  Typically, isolates from the dog are MRSP (methicillin resistant staphylococcus pseudintermedius). 

 

What does “MRS” mean?  MRS stands for “Methicillin Resistant Staph”.  Methicillin is an antibiotic that is the used as a marker to indicate multi-drug resistance.  So, the better terminology would probably be “multi-drug resistance”.   

Staphylococcus pseudintermedius  is a common bacteria found on the surface of the skin, or in the ear, mouth, nose or intestinal tract of 50% or more of healthy dogs.  Just because your dog is colonized with staph bacteria does not mean your dog is sick or has an “infection”.  These bacteria are considered normal flora….they should be present.  Not all Staphylococcus pseudintermedius are methicillin resistant (or multi-drug resistant).  The strains that are methicillin resistant are simply harder to treat due to a limited selection of appropriate antibiotics.  This is when topical therapy becomes vital to success!

Staph bacteria cause problems by taking advantage of the body’s weakened defenses.  For example, an allergy patient is prone to getting staph infections of the hair follicles (folliculitis).  A cancer patient receiving chemotherapy is more prone to infections; both skin and internal.  Thus, we would classify staph bacteria as an “opportunistic pathogen”:  typically causing no problem yet taking advantage of opportunities to overgrow.

 

What does the term colonized mean?  Is that the same as infected?  No, the terms are not the same.  Those dogs (or people) that carry the bacteria on their skin or nasal passages but have NO signs of any problem or infection are said to be colonized.  An infection would be characterized by inflammation (red, heat, swelling, pain, fever, discharge, etc).

 

How is MRSA different from MRSP (both are multidrug

1.  People: MRSA is a huge concern but MRSP is minor.  2.  Dogs:  MRSP is a major concern but MRSA is not.

3.  MRSA can affect both people and dogs

4.  MRSA can be transmitted from people to dogs and vice versa.

5.  MRSP can be transmitted from pets to people BUT this seems to be very rare!

*The zoonotic risk (people contracting MRSP from their dog) is very low.  This organism is not well adapted to cause disease in people.  Dog owners are exposed on a daily basis and there have only been a couple of reported cases of MRSP infection in people worldwide.  So, the risk is not zero but close!

How did my dog get MRSP?

The bacteria are transmitted from animal to animal via direct contact.  Healthy colonized animals are likely the ones spreading the bacteria.   De-colonization of these animals is impossible and attempts would likely lead to more antimicrobial resistance!

How can I limit my exposure to MRSP?  MRSP can survive in the environment for only a limited amount of time.  Luckily, disinfectants, such as bleach, are still effective in killing the bacteria.  Frequent hand-washing is still the single most important thing a person can do to prevent problems. 

How is MRSP diagnosed? By culture and sensitivity.  A small sample is obtained from a lesion via a swab and placed on culture medium.  The sample is then placed in an incubator and allowed to grow.  The colony is then identified and exposed to various antibiotics to determine susceptibility. 

 

What is the appropriate treatment for MRSP? Both oral & topical therapy are necessary!

Oral antibiotics are selected by the culture’s sensitivity (susceptibility pattern) and are used for an extended period of time…typically 4 weeks or longer.  Sometimes, the stain of bacteria is resistant to almost every antibiotic choice…thus the term “multi-drug resistance”.

Topical therapy is a vitally important part of the protocol.  Bleach (Na Hypochlorite) baths are used in human patients!  Canine Skin Solutions recovery Shampoo and Spray are comparable products for dogs with Na Hypochlorite as an active ingredient mixed with ceramides and essential oils to protect the skin surface……and there is no mixing.  

Is Quarantine of my dog necessary? No! MRSP is widespread in the population so strict quarantine is not necessary.  However, I would recommend common sense to help reduce the likelihood of transmission to other animals.  If your dog has been diagnosed with MRSP: 10 Safety Steps

1.  Avoid dog parks

2.  Avoid puppy classes

3.  Avoid doggie day care facilities

4.  Promptly remove stool from public places (MRSP can be shed in feces)

5.  Do not let your dog off-leash

6.  Avoid people or dogs that may have a compromised immune system

7.  Avoid direct contact with your dog’s nose, mouth, or anus

8.  Don’t let your dog lick a person’s face

9.  Toys and bedding should be regularly cleaned or  changed

10.  Keep MRSP positive pets off of people’s beds 

* Remember, hand hygiene is the MOST important means of preventing transmission!!

You cannot prevent your pet from getting MRSP because it is carried by so many healthy animals…..so relax.

Prudent use of antibiotics is the single most important fact that the medical community and the public must endorse.  The right dose of antibiotic, the right duration of therapy, and the right disease (not viral respiratory or otic disorders)!