MRSA THE FACTS
The letters MRSA are enough to strike fear in the hearts of many people but just how dangerous is the bug and are our pets at risk? Vet Roberta Baxter addresses these fears - and aims to separate the facts from the fiction.
Ever since we first heard about so-called flesh-eating bugs we've all been concerned about MRSA in humans. But, in fact, it has long been known that these bugs can affect other species too, including dogs. The public are now much more aware of MRSA, thanks to media attention and, in many ways, this is a good thing. However, over-sensational reporting can create fear and make dog owners worry either that their pets could infect them, or lose faith in their vets to the detriment of their dogs' welfare.
This article aims to clarify the situation and allay unnecessary fears. What is MRSA?
MRSA stands for methicillin resistant staphylococcus aureus; methicillin being a type of antibiotic and staphylococcus aureus (SA) a bacteria. Staphylococcus bacteria are found widely in all species. They are relatively common in humans but rather less so in dogs who more often have other staphylococcal bacteria. Though many people carry staphylococcus bacteria in their nose and throat and on their skin, our immune system is normally good at ensuring they cause no symptoms.
However, they may be associated with diseases such as acne, spots, boils and impetigo which are usually relatively easy to treat. Staphylococcus bacteria really only become problematic in rare cases where they gain access to deeper skin tissues or the bloodstream, for instance during an operation, or when contracted by someone who is already sick and has a suppressed immune system. In such cases they can cause infections of wounds and internal tissues. In most cases these infections respond well to antibiotics.
Like humans, many dogs have staphylococcus bacteria living on their skin with no symptoms, while others, who, for whatever reason, have reduced skin immunity (caused by an underlying skin problem such as an allergic disease, for example), may develop infections. Dogs who have surgery or are immunosuppressed occasionally develop deeper infections; again these usually respond well to antibiotics. However, some staphylococcus bacteria carry a gene which makes them resistant to some or all commonly-used antibiotics and, of these, methicillin resistant staphylococcus aureus are some of the most difficult to treat.
Two main types of human MRSAs exist: one is associated with resistance to antibiotics and is most commonly picked up in human hospitals, and another is less widely resistant to antibiotics and is usually found in the wider community. These bugs are no more infectious or 'vigorous' than other SAs, it's just that in the wrong individual (one who is immunosuppressed) or the wrong situation (a surgical wound) they become problematic because they are difficult to treat.
Where do infections come from? Although MRSA has been documented in humans since the 1960s and was first identified in animals in the early 1970s, it has recently become more of a problem due to an increase in its occurrence in the general population. Approximately 30 per cent of people in this country now carry MRSA with no signs of disease and although opinions vary as to the proportion of dogs who carry the infection it is thought that around two per cent do.
Exact identification of the types of MRSA involved in infected dogs show some interesting results. Many owners assume the most significant risk to their dog is the veterinary hospital, since infections occur most after operations. However, while some dogs go down with strains that appear to come from a veterinary environment, others contract human 'hospital' strains that can be traced to their owners and other handlers who have been in contact with a human hospital.
It therefore appears that some dogs going to the vets will be carrying MRSA (with no symptoms) which has come from their handlers. Even with the best hygiene practices this infection can then relocate through the bloodstream from the throat or skin to the site of surgery to cause a problem. Prevention of veterinary-acquired infections can be achieved by good hygiene practices. Although 30 per cent of humans appear to carry these bacteria, transmission from vets and nurses to dogs may be prevented by regular handwashing and, where necessary, the use of gloves and face masks during surgery.
Dog-to-dog transmission can be prevented by thorough cleaning of operating rooms and kennel areas - contrary to many people's understanding, many commonly-used antiseptics and disinfectants can kill these bacteria. In addition, attention should be paid to thorough preparation of the skin before surgery and good surgical hygiene.
However even the cleanest veterinary hospital deals with animals who carry enormous numbers of bacteria on their coats and are difficult to keep clean. It may only take a dog scratching off a dressing with a dirty nail to put bacteria into a wound and this is hard to prevent. Prevention of infections resulting from bugs already present in the dogs nose and throat is even more difficult but can be helped by ensuring dogs are as healthy as possible before surgery. Identification of possible carrier dogs can allow special care to be taken with them (such as isolation) and in some cases swabs can be taken from 'at risk' dogs to try to identify and treat any problems prior to surgery.
MRSA associated disease in pets is extremely rare but in some cases is sadly fatal due to the infection spreading through the bloodstream, damaging the heart and other organs, or the pain of a chronically infected wound. When dogs develop MRSA their chance of survival is best where the infection is recognized and treated rapidly. So any concerns about dogs who have had surgery should be addressed quickly. Signs of infection such as oozing of pus or mucusy discharge from the wound, inflammation around the wound, pain or depression and illness should all be investigated as soon as possible
However it is important not to panic - most types of wound infection won't be MRSA and will be easy to treat. Rarely, MRSA may also be associated with skin infections in dogs who have not had surgery; these may be difficult to treat and operations should be avoided in these animals. If MRSA is suspected, the vet can take a swab and send it for laboratory examination. This can identify the type of bacteria present. However, although finding out the type should be straightforward, identification of its resistance to various antibiotics can be less accurate and may take time.
Use of antibiotics other than penicillin and methicillin may therefore be a good idea while the results are awaited. Concerns regarding dogs suffering adverse reactions from such medicines have been voiced in the press but most of the antibiotics used are extremely safe. Treatment of dogs with MRSA is based on the use of alternative antibiotics and, where appropriate, topical antiseptics. In many cases treatment can be successful.
What about the human risk? Because MRSA is a risk to humans, particularly the very old and very young, and those who are immunosuppressed or about to have an operation, handling of infected dogs should be avoided, particularly by high-risk humans. Although we are far more likely to infect our dogs (infection is more common people) than vice versa, they can pa infections to their handlers. One documented case involved a family dog who was infected by his owner. The dog then passed the disease back to the owner so that although the dog showed no symptoms, the owner had a recurrent MRSA infection.
A similar case involved a cat in an old people's home who became a carrier and passed it t residents. However it only takes good hygiene to prevent this type of transmission and in most cases preventing contact between humans and pets is not justified. Those pets who come into contact with high-risk humans can be screened to ensure they are not carriers. So, should we be worried?
Undoubtedly canine MRSA infection extremely problematic when it happens and devastating when it proves fatal. However the risk of contracting it remains low at the present time and operations should not be avoided because of the fear of MRSA infection Instead, it is important owners work with their vets to ensure dogs receive the care they need to keep them as healthy as possible.
I WATCHED HER DETERIORATE BEFORE MY EYES.
Bella, a ten-year-old Samoyed, is believed to be one of the first dogs to die of MRSA in the UK. Owner Jill Moss of Edgware, London, has since launched a website (www. pets-mrsa.com) to educate owners and vets about the risks to animals. She is campaigning to bring about a change in veterinary standards relating to infection control.
Jill has received messages of interest and support from dog owners all over the world and Claire Rayner, best known as one of the UK's top agony aunts and who herself has been infected with MRSA, has agreed to become the honorary patron of Pets-mrsa. Jill said: "I was out walking Bella back in July last year when she chased a squirrel and ruptured her cruciate ligament. I took her straight to the vet who said she needed an operation immediately. "She had the emergency surgery and I knew that it would take her some time to recover.
"I took her home but she wasn't eating and seemed to be in a lot of pain so I called the vet out to check on her. After several days she got up and the wound burst so I took her back to the vet's. They kept her in for a week; she had a very high temperature and seemed to be quite distressed. She was put on a course of antibiotics and the veterinary staff kept squeezing the wound in order to expel the pus.
"I was getting very concerned about her condition and kept asking if they could refer her to a specialist but I was told there was no need. In the end, after I found out the wound had become infected, I took her to a specialist vet who rushed her in for emergency surgery. Unfortunately Jill's traumatic experience didn't stop there. She had been walking around barefoot while in the consulting room with Bella. Jill had a small cut on her foot and later discovered that she had become infected with MRSA herself.
She said: "The whole experience has left me feeling traumatized and angry. I don't have any children and I am not married so Bella was very important to me; she was my life. I didn't leave her side throughout and watched her deteriorate in front of my eyes. I feel she has been taken away from me unnecessarily and there's also a sense of guilt. If I had known there was a chance she had been infected with MRSA I might have been able to have done something more for her.
"The experience left me determined to warn other owners in the hope of preventing what happened to Bella happening to other much-loved pets which was why I set up the website. Since then I have been inundated with queries from owners all over the world concerned about MRSA. "I want to work with owners and vets to bring about better care and treatment for our pets - they deserve it."