Tuesday, October 7, 2008

Musings about MRSA

A friend recently asked me (yet again) about the "MRSA thing" and what can he do to prevent it?

Okay. MRSA has been around, and known about, since the 1970s at least. It stands for Methicillin Resistant Staphylococcus Aureus. It is a variant of the normal Staph A that every one of us already has on our bacteria-laden human bodies. What makes MRSA special is that R. Resistant. Bacteria gain resistance by several methods.

1. Antibiotics. In the good ol' days, patients could pressure their docs to write antibiotic prescriptions for viral issues like the common cold. Placebo effect, to be sure, for the cold. But the bacteria, they learn.

2. Antibiotics. Again. Patient is sick, takes antibiotics, feels better, stops taking antibiotics even though full prescribed course is not done. Patient may think 'I'll save these for later, in case I get sick again.' Uh-huh. By not finishing the antibiotics, some bacteria are left alive and kickin'... or actually, dividin', and they learned a lot about surviving that particular antibiotic. And what they know, so do their neighbors and offspring.

3. Bacterial communication. Okay, I know, it's strange to think that a bacterium, a simple single-celled organism, can talk. But it does. At least, it talks to other bacteria. They swap DNA frequently. We shake hands when we meet, and bacteria rub their membranes together and trade DNA snippets in lieu of discussing the weather. As a result, your new resistant friend set up from #2 doesn't keep the resistance a secret.

4. Darwin. Darn that man, it's all his fault. Whether you agree with him or not, life does adapt, evolve, and change. And with bacteria that change can be rapid. If they weren't microscopic, I'd have said visible. E. coli, for example, can divide every 20 minutes. This is exponential growth. 1, 2, 4, 8, 16... and so on until the bacteria run out of nutrients. The only growth curve in all of nature that can match the bacterial curve is ours. We are also reporducing exponentially. (I wonder if we'll die off when the nutrients are all consumed?) But because of that rapid growth, adaptation can occur at a high rate. Like all life, it appears to be imbued with a will to live. So the bacteria can learn resistance from natural selection processes as well.

But there's good news. Really. Because of #4, resistant bacteria do not reproduce as well as non-resistant strains. So take all of the antibiotic prescribed, even if you feel better. Invest in hand sanitizer. And eat that activa yogurt to re-establish the good bacteria before another resistant strain sets up. Resistant strains can't compete with the normal strains in a non-antibiotic laden system. And yes, that's why antibiotics cause diarrhea. They're not very specific about which bacteria they kill.

Furthermore, the bacteria is cultured out and then resistance-sensitivity tests are run on your personal infecting bacteria. The antibiotics you are given are specific to that strain of bacteria.

I laughed a lot when the media fastened onto MRSA like it was the next pandemic. MRSA is small potatoes in the hospital setting these days.
It's community acquired.
It's been around for decades.

Vancomycin kills it.

What the media failed miserably at noticing was the bacterium that scares even the ICU staff.
That would be VRSA.
Vancomycin Resistant Staphylococcus Aureus.
MRSA has a new family member.
Be afraid.

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