MRSA/MRSP (Methicillin-Resistant Staphylococcus aureus (MRSA), Methicillin-Resistant Staphylococcus pseudointermedius (MRSP))
We receive many phone calls from clients asking us to refill antibiotics, oral or topical, for their pets for problems that occur frequently, such as skin and ear infections, sneezing, or urinary tract infections. Antibiotics at our office are generally not refilled without checking your pet. We need to see your pet before refilling antibiotics, which can cause confusion and frustration for our owners.
Concerns about often expressed are:
- Why not just refill our antibiotics when they worked last time?
- Why do we need to spend money to have you see our pet when the antibiotics worked last time?
The answer…multi-drug resistant bacteria (MRSA/MRSP), or SUPERBUGS.
These bacteria aren’t called superbugs for no reason. They are normal bacteria that have mutated to become resistant to multiple antibiotics. The reasons for the mutation is simple…misuse of antibiotics. Misuse refers not only to the judicious refilling of antibiotics, but also not finishing a course of antibiotics as prescribed, reusing leftover antibiotics (including ear medications), or not using antibiotics at the proper dose or duration.
The development of superbugs is not one to take lightly as these infections are becoming common not only in veterinary medicine, but also in human medicine. In addition, MRSA and MRSP can spread to humans from their pets and vice versa.
What is this MRSA/MRSP?
Staphylococcus aureus is a common bacteria that lives on people, normally on the skin or in the nose, and can be spread from people to their pets. Staphylococcus pseudointermedius is a similar bacteria that normally lives on dogs. In some pets, both of these “normal” Staph bacteria can cause infections, usually of the skin or ears.
MRSA and MRSP are Staphylococcus aureus and Staphylococcus pseudointermedius that have developed resistance to multiple antibiotics. MRSA and MRSP can be found on healthy pets and are usually harmless. Pets that are sick, hospitalized, or taking antibiotics are prone to infections from MRSA and MRSP. The bacteria most commonly cause skin or ear infections similar to “normal” Staph bacteria. However, since MRSA and MRSP are resistant to multiple antibiotics, infections need to be identified for proper treatment.
Other infections, such as urinary tract infections or pneumonia, can also be caused by MRSA and MRSP. If left untreated, MRSA and MRSP can lead to other serious disease such as sepsis.
What are some common signs of this condition?
- Crusts, bumps on the skin
- Draining discharge from the skin or a wound
- Hair loss or redness of the skin
- Redness, discharge, or foul odor from the ear
- Straining to urinate, blood in the urine, and an increase in thirst/urination if your pet has a urinary tract infection
- Coughing, sneezing, difficulty breathing, and rapid breathing if your pet has a respiratory tract infection
Infections with “normal” Staph bacteria and infections with MRSA/MRSP appear identical.
What causes MRSA/MRSP?
Staphylococcus aureus and Staphylococcus pseudointermedius mutate to form MRSA and MRSP. The mutation allows the bacteria to survive typical antibiotic treatments. Causes of mutation may include misuse of antibiotics, exposure to several types of antibiotics, and recent antibiotic administration.
Pets with infections from MRSA and MRSP usually have an underlying cause that must be identified and treated, if possible. Examples of underlying causes include allergies, parasites, thyroid or adrenal gland diseases, diabetes, skin disorders, or immunosuppressive therapies.
Pets undergoing surgery or hospitalization are also more prone to infections from MRSA and MRSP.
How is MRSA/MRSP diagnosed?
In addition to the signs listed above, your veterinarian will also need to know your pet’s history of previously treated skin or ear infections. Your veterinarian will also need to know if you are currently treating your pet for other diseases such as thyroid disease or diabetes.
Your veterinarian might recommend one or more of the following tests to help confirm your pet’s diagnosis:
- Cytology – A microscopic examination of the bacteria, yeast, and cells on your pet’s skin and/or ears will determine if only bacteria is involved or if other infections need to be treated.
- Culture and Sensitivity – A swab of your pet’s skin and/or ears will be taken. A urine sample will be collected if your pet has a urinary tract infection. The bacteria will be identified with a culture. A sensitivity will determine which antibiotics can be used to treat your pet’s infection and to determine whether or not it is MRSA or MRSP.
Your veterinarian might recommend one or more of the following tests to help rule out any other conditions:
- Blood Chemistry – A blood chemistry will help evaluate organ function and assess for disease elsewhere in the body.
- Complete Blood Count (CBC) – A CBC will evaluate your pet for conditions such as anemia, inflammation, or immunosuppression.
- Thyroid or Adrenal Testing – Dogs with thyroid or adrenal gland disease are prone to infections from normal bacteria.
- Additional Skin Testing – Parasites can be identified microscopically with a skin scrape, and a ringworm culture may be recommended to rule out fungal disease. A biopsy of the skin may also be recommended to rule out other skin disorders as the underlying cause.
- Other diagnostics – Your veterinarian may recommend further testing such as a urinalysis or x-rays depending on other signs your pet may be showing.
What are some of the treatment options?
- Topical therapy – Repeated, long-term treatment with medicated cleansers, ointments, shampoo, mousse, sprays, and/or wipes for skin and ear infections.
- Oral antibiotics – Your veterinarian may also prescribe several weeks of oral antibiotics depending on your pet’s signs and the severity of your pet’s infection.
- Repeated follow-up testing – A cytology and culture/sensitivity may help determine proper length of treatment and whether your pet is responding to the treatment appropriately.
- Underlying Conditions – Specific treatment may be started, such as thyroid medications or treatment for parasites.
What does this mean for my pet?
- The prognosis for MRSA and MRSP infection is good; however, your pet can continue to carry the resistant bacteria well after the infection has resolved
- It is very important to finish all medications as prescribed by your veterinarian. Do not stop treatment even if your pet’s signs appear improved.
- It is important to return for recheck exams and diagnostics as recommended by your veterinarian as the signs may be resolving, but only your veterinarian can determine if the treatment duration was appropriate based on their findings.
- Reinfection is possible if the underlying cause is not identified or treated. Lifelong treatment of the underlying cause may be required
When do I need to call the veterinarian?
If your pet shows any of the following signs, or if you have any concerns about your pet, call your veterinarian as soon as you can:
- Your pet’s condition does not improve or worsens
- Your pet develops side effects on oral antibiotics (vomiting, diarrhea, not eating, and any other side effects as explained by your veterinarian)
- Your pet does not behaviorally tolerate the topical treatments well
- Your pet develops other signs that may indicate spread of infection such as pain, lethargy, vomiting, diarrhea, weakness, or a decreased appetite.
Where can I find additional reliable information about this condition?
The Centers for Disease Control
Are there any human health concerns to consider?
- Both MRSA and MRSP can be spread to humans from their pets and vice versa. Humans can become infected with MRSA, but rarely become ill from MRSP. However, humans can spread MRSP to their other pets.
- Regular hand-washing is important to prevent spread of the bacteria.
- It is important to clean bedding and toys with soap and hot water at least weekly during treatment.
- If you or your pet have been diagnosed with MRSA or MRSP, be sure to cover your wounds with bandages until completely healed.
- Pets infected with MRSA/MRSP should be kept away from people that are immunocompromised.
- See your physician with any health concerns that you have that may be linked to MRSA or MRSP