Let's start with MRSA. I'll translate, first from alphabet to medicalese, to English. French translation will require a different author. The initials stand for Methecillin Resistant Staph. Aureus. Staph. Aureus is a round (cocci) bacteria commonly found on the skin. While we used to think that all of these potentially disease causing cocci were Staph aureus, it turns out that this is a pathogen of people and other species have there own species of Staph. Here is group of Staph as seen under the microscope, a Staph meeting as it were.
The M is for methecillan, an antibiotic and the R is for resistant. MRSA is resistant to, that is not killed by methecillin or any penicillin type antibiotic. The problem is that many of these bacteria also develope multi drug resistance, that is that many antibiotics will not affect them. As you can see this can cause a big problem.
MRSA has become a huge source of complications in human hospitals as this is a place were there are alot of sick people, and bacteria, and antibioitics to stimulate resistance. (We can talk about how bacteria become resistant in another post if anyone comments and is interested)
Dogs can get colonized by MRSA. They get it from their owners and it might not ever cause a problem. However, if they should have some weakening in their immune system, allowing these bugs to get a foothold, then we can have a problem. At our practice, we have seen several cases of MRSA recently. In each case we were able to trace the source of infection back to an owner that had been treated in some sort of health care facitlity.
What about the other intitials you ask? Well, as I alluded to earlier, other species of animals have there own staph bacteria. In dogs they were reclassified as Staph. intermedious (SI) and most recently, Staph. pseudintermedious. Here is a picture of staph, closer up. Can you tell what species it is? No one can just by looking. Special tests are needed.
In fact, you can't tell if this is a resistant staph or just a plain old staph just by looking at a photo micrograph. Sensitivity to antibiotics is determined by doing cultures and sensitivities in the clinical path lab. We have seen an increase in the number of MRSP infections in our practice over the last few months. I'm not sure if that is because more of our staph infections are resistant to methecillin, or if we are just more aware and doing more cultures. These animal staphs can colonize people and cause diseae if the opportunity arises.
Now, were do we see most of these resistant staph infections in our animal patients? The number one location is in the ear. That is why your veterinarian should not just look at an ear like this and send you home with anti biotics.
Here is the other very common location for bacterial infection, the skin. People often mistake this type of lesion as ringworm (another topic for another day) but this is a classic presentation for a staph infection in a dog. These also need to be treated with appropriate antibiotics, both topical and systemic.
WASH YOUR HANDS!! Do it frequently and do it well. Use antibacterial soap. Use the hand sanitizer stations that popped up during the swine flu scare. These will kill bacteria as well as flu viruses.
Keith Niesenbaum, VMD