MRSA & Therapets

Over recent years there have been a number of reports of the presence of Methicillin Resistant Staphylococcus Aureus (MRSA) in dogs (ref. 1.and 2.); of suspected transmission of MRSA between pets and humans in veterinary clinics and in the household (ref. 3. and 4.); of asymptomatic carriage of MRSA by a pet dog associated with MRSA infection in humans (ref. 5.); and of MRSA carriage in a pet therapy dog (ref. 6.).

Canine Concern Scotland Trust (CCST) is a charity which manages the activities of 511 Therapets working throughout Scotland. All of these Therapets make regular visits to old peoples' homes, to hospitals where they mainly visit the chronically sick or elderly, and in some cases to hospices. A minority of Therapets also visits schools and youth organisations to promote education in responsible dog ownership.

All of the Therapets are owned by Therapet visitors who have agreed to abide by the CCST Therapet Health Protocol. This requires that each Therapet must have annual vaccinations against common canine infections including Kennel Cough (Bordetella) vaccination; regular deworming; preventative control for fleas, ticks and other external parasites; an annual health check by a veterinary surgeon who will be informed by the Therapet visitor that the dog will be visiting chronically ill and potentially immuno-compromised patients, and ask for special attention to be paid to dental health and ear, eye and nose conditions; regular grooming and bathing with antiseptic shampoos; and bactericidal wipes for the face and heads of Therapets to be used between patients when they are visiting.  All Therapets who have been unwell for any reason are withdrawn from visiting.

With the recent reports of MRSA in dogs, and the likelihood of Therapets being exposed to human MRSA infection when visiting, the Trustees of CCST agreed to conduct a sample survey of Therapets throughout Scotland to check if within the sample there was any evidence of MRSA carriage states having been established. 50 dogs were selected, and they were taken to six veterinary centres in Grantown on Spey (Highland), Aberdeen (North-East Scotland), Edinburgh, Broxburn (Lothians), Glasgow and Dumfries (South Scotland) between 13th February and 22nd February 2007. At these veterinary centres buccal and nasal swabs were taken from each dog, and the swabs were sent in transport medium to Nationwide Laboratories for examination.

The 50 Therapets selected consisted of 25 male and 25 female dogs, and their average age was 7.3 years old.

The swabs were streaked onto Baired parker agar with ciprofloxacin, and the heads were snapped off into Giolotti-Cantoni broth, and the subcultured on to Baired parker agar with ciprofloxacin (ref. 7.) 4 of the 50 samples showed weak positive results on the Mastalex MRSA latex agglutination kit. After further investigations, however, it was determined that these isolates were not MRSA. The four Therapets who initially showed weak positives were withdrawn from duties for 1 month and then retested. A 51st Therapet who shared a household with one of the four weak positives was also tested. All five of these further tests were negative for MRSA using the same test procedure.

This survey shows that, while working in a challenging environment where the risks of acquiring MRSA is greater than normal, the 51 Therapets selected were clear of MRSA at the time of testing. It also suggests that, with the application of an effective Therapet Health Protocol and the use of reasonable bio-security measures, the risk of MRSA establishing either a transient or permanent carriage state in a Therapet can be minimised.