Culture Club: Why More Careful Testing Means Better Medicine (and Saves You Money, Too)
For some reason I’ve always been attracted to dermatology. I find it challenging and endlessly fascinating. Though I recognize that plenty of my colleagues think it a girly art better suited to the tender sex (relative to surgery, for example), the truth is that derm is a thoughtful, intellectual pursuit that most alpha male veterinarians couldn’t even begin to wrap their heads around.
Case in point: I recently attended an interesting local lecture on how MRSA (methicillin-resistant staphylococcus aureus) and MRSI (methicillin-resistant staphylococcus intermedius) infections are wreaking havoc among more of our patients than ever before.
No, it’s not just humans; animals are suffering a higher rate of these bugs, too. Which is one reason why veterinarians are increasingly relying on cultures to make appropriate antibiotic decisions.
So it is that when your cat goes in for the standard lower urinary tract disease issue, it’s no longer good enough to start the Clavamox (augmentin) and hope for the best. Not when it’s a good possibility that she doesn’t even have an infection. Getting a sample of urine (admittedly challenging) is the ideal approach. This gives us the ability to know, a) whether antibiotic therapy is even appropriate, and b) which antibiotic is likely to kill this bug best.
The problem with this scenario (be it urinary tract disease or a life-threatening pneumonia) is that waiting two or three days for an inkling as to how best approach these cases isn’t feasible, not when treating her with something (anything!) has a chance of making her feel better NOW.
When quality (not to mention survival) of life is crucial, any broad spectrum antibiotic with general effectiveness against the kinds of bacteria known to most commonly populate these areas (be they bladders, skin, lungs or teeth) is often indicated … immediately.
But there are grey areas … and uncertainties … which is why there are cultures.
Cultures are pretty simple: Your veterinarian gets a sample from the abscess or pustule on the skin, the ear discharge or the nasal discharge. Perhaps she sends a sample of urine or sputum to the lab.
The lab, in turn, smears these ill-gotten gains onto a petri dish, incubates them so they can grow willy-nilly, and later applies drug "patches" to the growth to see which drugs best affect the offending bacteria. Pretty simple, right? It’s just painstakingly meticulous work that most of us prefer to outsource to specialists (i.e., microbiologists).
Which is why it’s so expensive. And that’s largely why your veterinarian might not be in the habit of ensuring that each and every possible infection is tested for the presence of bacteria … and for the likelihood that said potential bacteria will actually respond (as in, ultimately be killed) by the antibiotic that’s been prescribed.
But back to the lecture I attended.
The whole point of the talk (offered by a local dermatologist and sponsored by a big-name drug company) was that veterinarians NEED to culture skin more assiduously. Too many of the infections we’re attempting to treat with broad-spectrum antibiotics are increasingly incapable of killing the bacteria we’re confronting.
Culturing the skin means being able to adjust course with more appropriate antibiotics as soon as possible so that a minimum of potential resistance is incurred in the process (inappropriate antibiotics = antibiotic resistance).
Sure, it’s more expensive for the client in the short-run, but it’s undeniably the best course when it comes to both human and animal safety in the emerging war against MRSA and MRSI infections.
Unfortunately, the well-referenced and compelling lecture ended in the drug rep’s painful diatribe on how a system-by-system chart detailing which antibiotics are best represented the ideal approach to antibiotic selection, totally undermining the entire point of the dermatologist’s lecture.
Indeed, it was so sad (for the derm) that I could only ask (in my most innocent manner possible): "Isn’t it best for us to do what Dr. X says and culture first so we only dispense a minimal amount of the trial antibiotic while we await the microbiology results? I mean, relying on a chart is so 'old school,' right?"
With the same drug rep approach pervasive in human medicine — not to mention animal agriculture — is it any wonder MRSA and MRSI infections are on the rise in humans and animals?
But then, I’m just a girl. What do I know?
Dr. Patty Khuly
Pic of the day: Micrograph of methicillin-resistant Staphylococcus aureus bacteria, courtesy of CDC Public Health Image Library