Visiting Veterinarian : Resistant bacteria
A mere 80 years ago, people often died from relatively minor wounds if they became infected with Staphylococcus aureus - a common bacteria usually referred to simply as "staph." Childbirth, surgery, lacerations, broken bones, pneumonia - any event allowing bacteria to penetrate the body could result in death from infection. Then, in 1928, Alexander Fleming, a bacteriologist at St. Mary's hospital in London noticed that mold on a discarded culture plate was inhibiting bacterial growth. His observation eventually led to the discovery of penicillin and other antibiotics. Literally translated as "against life," antibiotics are drugs that selectively kill bacteria or inhibit their growth. As doctors began prescribing antibiotics, the death rate from infections dropped dramatically and life expectancy rose. Some scientists even predicted the "end of infectious diseases." Alexander Fleming was more cautious. In 1945 he wrote in The New York Times: "The greatest possibility of evil in self-medication is the use of too small doses so that instead of clearing up infection the microbes are educated to resist penicillin and a host of penicillin-fast organisms is bred out which can be passed to other individuals and from them to others until they reach someone who gets a septicaemia or pneumonia which penicillin cannot save."
He was right. Today we have MRSA. Methicillin-resistant Staphylococcus aureus. Quite a mouthful. What does it mean? Let's start with plain old staph. These bacteria are normally found on many people's skin or the lining of their noses. It's thought that about one third of the population carry staph without any signs of illness. Such individuals are said to be "colonized" rather than "infected." If bacteria enters the body through an injury, it can cause infection. If the patient in question has a weakened immune system, this can be serious, even fatal.
In the beginning days of antibiotic usage, the majority of staph infections could be cured with penicillin. But Mother Nature is crafty. By the 1950s, some populations of staph had mutated to be resistant to penicillin. So scientists developed new, stronger types of penicillin, such as methicillin. And the bacteria mutated again. And again. Today, these "MRSA superbugs" are resistant not only to all types of penicillin but to many other antibiotics as well. And they can kill you, just like they did back before Fleming and his moldy culture plate.
Most MSRA infections in humans occur in hospitalized patients or those who have had surgery, but recently cases have started to pop up in people who do not fit this picture. This new form, called "community-associated" or CA-MRSA, didn't originate from hospitals. It is a different strain and it's showing up in places like military barracks, prisons, athletic locker rooms, even schools...places where people are crowded together, where there is skin-to-skin contact, where small skin wounds and abrasions may occur. Poor hygiene and contaminated surfaces like athletic equipment or tattooing instruments probably contribute. Although usually not life-threatening, CA-MRSA can be fatal. Last year a 17-year-old boy died in Virginia from an infection traced to his school, and there is growing concern in the medical community about the rise in MRSA prevalence and the dearth of effective treatment.
What in the world does this have to do with veterinary medicine? A few things. In recent years there have been increasing reports of dogs, cats, horses, even rabbits, affected with MRSA. Are they responsible for this new CA-MRSA? Epidemiological studies suggest it's more likely the other way around. As CA-MRSA spreads among people, we pass it to our pets. Many colonized animals self-cure without treatment but an unknown number become asymptomatic chronic carriers. Rarely, an animal will develop clinical disease. As with people, these cases are most frequently associated with wounds and surgery, particularly in immune-compromised individuals. Diagnosis is made by culturing the affected site and testing the bacteria for antibiotic sensitivity.
Another way veterinary medicine impacts MRSA is through our reliance on antibiotics. Just as you shouldn't ask your doctor for antibiotics for a cold or the flu (these are viruses and antibiotics won't help anyway), don't ask your veterinarian for them for your pets in instances when they assure you such treatment is unwarranted. Veterinarians need to resist the pressure to prescribe "something" to reassure an owner, even though we know a pet is likely to self-cure with a little T.L.C. and tincture of time. On the other hand, if your physician or veterinarian does prescribe antibiotics, follow the instructions exactly. Underdosing or not finishing the prescribed course can contribute to resistance as much as overuse does. Veterinarians also need to work with scientists, farmers, and government agencies that are working to address the problem of misuse and overuse of antibiotics in food animals and livestock.
What about therapy dogs that visit patients in the hospital, the cat that lives with grandma at the nursing home, the ponies used in therapeutic riding programs? These animals should avoid contact with MRSA-infected patients to reduce the risk of getting colonized and spreading the bacteria to others. Conversely, animal visits to high-risk humans should be cleared with their physicians. Veterinary offices have a higher infection rate than many other venues, so we need to be extra thoughtful about not spreading bacteria between patients. Now I'm not suggesting you stop patting your puppy, cuddling the cat, or grooming that pony, nor do our pets pose any great risk to the majority of people. What I am suggesting is that we act locally to deal with this global issue of antibiotic-resistant bacteria.
Use common hygiene practices recommended by physicians, such as not sharing personal items such as towels, sheets, and clothing. Use Band-Aids on your boo-boos. Check with your physician if a wound is red, swollen, warm, tender, or drains pus. What about Fido's boo-boos? Wear gloves if you need to clean or medicate a wound topically. Be extra careful if you are in a high-risk group. If the boo-boo is draining pus, seek veterinary care.
Finally, wash your hands. Really. It's one of the best things you can do to prevent bacterial spread. Do it right. Use soap. Not anti-bacterial soap. According to the Mayo Clinic, these are no more effective than regular soap and may contribute to the problem of resistance. Scrub. At least 15 to 20 seconds. Be thorough. Make your kids wash up too. For small children, specialists suggest having them sing a short song to be sure they scrub long enough. I think I'd better try that too. Okay. All together...row, row, row, your boat...
