MRSA in a Pet Dog

Case History:

Angus, a two year old neutered male Yorkie presented to us in July for a wound on his back. The owner was unsure as to what caused the lesion, but did say that possibly it happened from a fight with the other dog in the house or a scrape from his kennel. At the time of presentation, Angus was mildly dehydrated and his blood work revealed no other significant abnormalities. The wound was approximately 2 inches by 2 inches. The wound was cleaned and Angus was sent home on antibiotics and pain control.

Showing Sides & Back covered in Wounds, several days into treatment

On the recheck exam 3 days later, the wound had become quite extensive and areas of the skin on his back were dying and falling off. An additional antibiotic and anti inflammatory medication was started and the wound was thoroughly cleaned and bandaged. Additional testing was submitted to check for Valley Fever and Addison’s disease; both of those tests later came back negative.

Progressing well, lots of healthy tissue

On his recheck exam in 3 days, the skin around the wound had become affected and his entire back was red and the skin was raised. The skin of the presenting wound continued to peel off as it was no longer healthy. With the wound becoming substantially more severe and not improving with his current therapy, a skin biopsy was submitted as well as a fungal and bacterial culture of the wound to try and determine the underlying cause so that the appropriate therapy could be initiated. The bacterial culture came back that he had a Methicillin-Resistant Staph Aureus infection, or MRSA. The importance of diagnostic testing cannot be reinforced more strongly than by looking at the case of Angus and his skin wound.

The treatment plan for Angus was altered by changing his antibiotics to Clindamycin and Doxycycline, both antibiotics were useful in treating his strain of MRSA. His wound had become quite extensive and a large portion of skin on his back had fallen off. Daily bandage changes and wound care were performed to keep the wound as clean as possible and promote good tissue healing. When the skin was healthy enough and the dying portions had fallen off, the skin was closed surgically and wound management was continued post surgery. Angus was cared for approximately 7 weeks and he is healing extremely well and now has hair growing back over the previous lesion. Nasal and rectal culture swabs were taken and no MRSA was isolated from those samples. Angus is a happy, healthy boy at this time and is thankful for the care he was give here at Alta Mesa Animal Hospital.

MRSA Information:

A little about MRSA…(information taken from www.aahanet.org and more information can be found by searching that site)

Methicillin Resistant Staph Aureus is a bacterial strain that cannot be treated by the Penicillin class of antibiotics. This bacterial strain has developed resistance to antibiotics often used, thus making it more difficult to treat. MRSA has become a very serious cause of infections in human medicine and is responsible for many nosocomial infections, or infections acquired while in the hospital. Bacterial infections can be diagnosed by taking a sample and submitting it to a lab where they can perform a culture to determine what bacteria is present and a sensitivity to see what antibiotics will be appropriate for getting rid of that type of bacterial infection. In our animal patients, MRSA should always be considered when dealing with non-healing or necrotic skin wounds. Proper hand washing hygiene and isolation protocols should be taken whenever you suspect a possible MRSA infection. Contact your veterinarian if your pet has a skin infection and make sure to contact your human physician if you have any concerning lesions yourself.

By: Andrea L. Swisher, DVM

UPDATE: Angus fully recovered and repeatedly tested negative for MRSA on culture. He was adopted to a wonderful new family.