Antibiotic-Resistant Infections in Dogs

MRSA is caused by bacteria that is resistant to antibiotics. This happens because every time your dog gets sick and is treated with antibiotics, there are always a few survivors (bacteria) that now are resistant to that antibiotic. These bacteria will pass on the resistance to other bacteria and this will keep happening until there are millions of bacteria that are drug resistant. Consequently, when your dog gets an injury or illness these bacteria will then take advantage your dog’s weakened immune system.

The Staphylococcus bacteria is often found on people and dogs without causing illness. You can be a carrier and not even know, but if you come in contact with your dog when he is sick or has an open wound he may get MRSA. Two and a half million people in the U.S. are carriers of the MRSA bacteria and they do not even know it, but they can pass it on to others with weakened immune systems or injuries. Actually, the majority of cases reported were caused by contact with a person who has or is a carrier of MRSA.

Antibiotic-resistant infection or methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common causes of antibiotic resistance in dogs. MRSA infection can be life threatening because it is hard to get rid of as it resists the antibiotics that veterinarians usually prescribe such as penicillin and amoxicillin. Your dog can be infected through a skin abrasion, cut, incision from surgery, or from your dog’s ears or nose. This is most often seen in animals that have been treated with antibiotic therapy or those in crowded situations, such as a breeder. MRSA is extremely contagious and can be passed from people to dogs and vice versa.

The most commonly recognized symptoms of MRSA are sores or injuries on the skin that will not heal. Some of the other symptoms of MRSA are:

• Abscesses or ulcers
• Pimples
• Rashes
• Skin peeling
• Bald patches anywhere on the body
• High body temperature
• Frequent infections – can be any infection from a mild skin infection to a life-threatening lung infection like pneumonia
• Secondary infections – more than one infection (i.e. skin and urinary infections, bloodstream and lung infection) at the same time
• Unusual infections – pyomyositis (infection of the skeletal muscles), endocarditis (heart muscle infection), and tuberculosis

MRSA is caused by contact with someone who either has or is a carrier of MRSA. The most common cause of MRSA in dogs is people. Here are some risk factors to avoid to keep your dog from getting MRSA:

• Exposing your dog to others when he has an injury or illness that lowers his resistance
• Using kennels or doggy day care when your dog has an open sore or illness
• Repeated use of antibiotics
• Stopping antibiotics before they are gone; always give your dog all of the medication the veterinarian gives you

Your veterinarian will need to do a complete physical examination, which will include weight, body temperature, blood pressure, and heart rate. He will check your dog’s entire body for skin lesions or rashes as well as inside your dog’s mouth, nose, and ears. Be sure to tell your veterinarian if your dog has had any injuries or illnesses recently, or if he has been exposed to others who may have MRSA. You should also let the veterinarian know if your dog has gone to doggy day care or a kennel recently. List the symptoms you have noticed, when they started, and if they have gotten any worse.

The veterinarian will need to run some tests on your dog to rule out other illnesses. Some of those tests are a complete blood count (CBC), glucose test, urinalysis, and fecal exam. A nasal swab will be taken for a bacterial culture, which is the most important test to diagnose MRSA. The veterinarian may also get a swab from one of the infected wounds or sores on your dog.

The veterinarian will start with a bacterial culture and sensitivity test to choose the best antibiotic, and prescribe a special shampoo and topical medication to treat any sores or open wounds. Some of the antibiotics commonly used for MRSA are Clindamycin, Doxycycline, Rifampin, Fluoroquinolones, and Minocycline. Many times, your veterinarian may suggest or prescribe probiotics for your dog to take daily. If your dog has any lesions, the veterinarian will prescribe a topical antibiotic such as Neomycin.

Your veterinarian may prescribe a medicated shampoo with chlorhexidine to bathe your dog once or twice a day as long as he thinks it is needed. Be sure to wear gloves when bathing your dog, changing bandages, or washing your dog’s belongings because MRSA is very contagious between dogs and people.

Wash all of your dog’s bedding, food dishes, leash and collar, toys, etc. Throw away bones or chews that your dog chews on. Clean any lesions and surgical incisions with 70% alcohol. If your dog has abscesses or open skin wounds that will not heal, your veterinarian may decide to do surgery to drain or remove the wound.

Since MRSA is resistant to many of the commonly used antibiotics (i.e. amoxicillin, ampicillin, penicillin), your veterinarian will have to use a stronger medication such as oxacillin, clindamycin, or doxycycline. Since it is so difficult to treat MRSA, a small infection on the skin can turn into a deadly infection of your dog’s heart valves, joints, bones, and bloodstream. That is why it is so important to take your dog to the veterinarian if you see a sore that is taking too long to heal.