Most readers have heard of MRSA (methicillin-resistant Staphylococcal Aureus.) This “superbug” has been in the human medical news a lot, as several reports of deaths (often among younger athletes who contracted the bacterium from “work-out” facilities) have been reported. Yet it may surprise you the MRSA and related bacteria are increasing among pets as well. This article will teach you what you need to know about MRSA and how to deal with a MRSA pet infection.
MRSA is the acronym for Methicillin-Resistant Staphylococcal Aureus. Staph aurues is a common human bacterium that can occur on pets as well (although pets, particularly dogs, are usually infected with a related Staph bacterium called Staph Pseudintermedius.) Methicillin is an antibiotic, but methicillin-resistant Staph are not killed by methiciliin or other antibiotics that typically are used to treat Staph. These methicillin-resistant Staph are considered “superbugs” because they can be hard to treat, take a long time to treat, often require treatment with very expensive antibiotics (and it’s become harder to find antibiotics that kill MRSA,) and as a result are more likely to be fatal then non-MRSA bugs. This means prevention, when possible, and early diagnosis and aggressive treatment are a must in order to protect your pet and yourself.
Staph aureus is a common human pathogen, and many people (estimates are 33% of people carry Staph in their nasal passages and 2% carry MRSA) carry the bacterium harmlessly in their nasal cavities. IF the bacteria leave the nasal cavity and infect another part of the body (as through a cut in the skin) they can quickly invade the bloodstream and cause septicemia, a deadly and often fatal infection of the entire body. In people this typically happens when handwashing is not done properly and the nasal MRSA is spread by touching another person or inanimate object that can then cause an infection when a susceptible person encounters the bacteria.
In pets, usually dogs, either Staph aureus (MRSA) or more commonly Staph intermedius (MRSI) infections can occur. Dogs and people can become infected through environmental contamination or by infecting each other (people can infect other people or dogs and dogs can infect other dogs or people.)
How Do I Know if My Dog Has MRSA?
Usually MRSA presents as a skin infection since most Staph infections in dogs tend to present with a dermatitis. Staph skin infections can appear in several forms. Typically small pustules (pimples) occur, although because they are fragile they easily rupture, leaving a red or dark inner circle surrounded by scale (a bull’s eye lesion.) Small red bumps, called papules, may also be present; these lesions most commonly occur on the less-haired areas of the body such as the abdomen and groin. In some dogs, typically shorter-haired breeds such as Labrador retrievers, they exhibit a moth-eaten appearance of partial areas of circular hair loss (alopecia) over their sides and their backs. Many dogs with Staph infections are itchy. Many dogs with (chronic) skin infections also have other diseases such as allergies and thyroid or adrenal dysfunction.
MRSA infections look just like “plain old” Staph infections, but there is an important difference. MRSA infections don’t get better when treated with antibiotics (or they improve but never really heal and continue to be present.) The only way to diagnose MRSA is through a skin culture. This can be done simply by swabbing the skin surface or through a skin biopsy (a biopsy is recommended for chronic skin disease, skin disease that doesn’t look typical, or if a culture of a skin swab is negative and MRSA is still suspected.)
I have also diagnosed some of these infections in the bladder and ears as well as the more common skin presentation.
How is MRSA Treated?
As a holistic veterinarian, I am encouraged that my traditional dermatology colleagues are finally recommending NOT using antibiotics for routine, simple skin infections. Instead they recommend frequent bathing with topical antimicrobial shampoos (but recommend not using injectable or oral antibiotics.) Research shows that simple, uncomplicated skin infections will heal without using oral antimicrobials if treated early and aggressively. Holistic veterinarians also use various herbs (astragalus, Echinacea,) for immune support and natural herbal antimicrobials (olive leaf, Oregon grape, etc.) to encourage quicker and longer-lasting healing.
Because MRSA is a tough bug to kill, and because it often develops when inappropriate and long term antibiotic treatment is used to treat any problem, specific antibiotics must be used, along with topical shampoos and herbal remedies, in order to kill MRSA. A sensitivity test, done alongside the skin culture, suggests which antibiotics MIGHT be helpful in killing MRSA. In general most antibiotics that are routinely used in veterinary practice are ineffective against MRSA. MRSA is typically only sensitive to expensive “human” antibiotics that must be given for 1-2 months or longer. Because MRSA can be fatal, especially in humans, it is recommended to save the “newer” more aggressive antibiotics for life-threatening infections in people and not use them to treat skin infections in pets.
Due to increased resistance to the Staph and because antibiotics must be used for extended periods in order to kill the Staph; probiotics should also be provided to the pet. Because the infection can be transmitted by objects, anything that pet has contacted such as blankets, pillows, or toys should be washed thoroughly and regularly.
Treatment is continued until the skin looks normal AND a repeat culture fails to identify the Staph bacterium. Ongoing care with regular bathing and herbs or homeopathics are used as dictated by each case.
The takeaway message is this:treat skin infections early and aggressively without using antibiotics except for serious infections. If the infection is not better the skin may need to be biopsied and cultured to confirm the diagnosis. Regardless of whether or not antibiotics are needed or are used, regular bathing and the use of immune-stimulating herbs and probiotics are essential.
Note-This photo shows one of the many faces of MRSA. This pet was diagnosed with “allergies and infection” but failed to improve until I properly diagnosed its MRSA infection.