CA-MRSA, Bogeyman Extraordinaire

There's been a ton of news recently with regards to community-acquired MRSA--school closings, cancellation of sports events, deaths, rioting in the streets, mass panic. See this NY Times article.

The CDC has adroitly headlined recommendations on their website. One wonders how many hits they've gotten recently.

Wouldn't want to catch MRSA. It can kill you, you know. Keep your kids home from school. Keep them out of sports.

MRSA is now the most common cause of skin infections seen in the ED. It's a common question for med students--how would you treat CA-MRSA versus hospital-acquired MRSA, which is still much more common? The answer is a drug switch: Bactrim or clindamycin instead of vancomycin. Patients in contact isolation for MRSA are common. One of my first patients was a woman who likely turned septic and developed MRSA tracheobronchitis. Not so easy to treat; she was in the ICU for weeks. I've seen her since for a hysterectomy, and she seemed well. She had MRSA from her chronically open and weeping leg wounds. She was immobile.

Superbugs are scary, I admit. Clostridium dificile is scarier to me than MRSA because sepsis and invasive disease can just as easily be caused by bugs that are susceptible, and kill you anyway. So, MRSA is more difficult to treat--but the main problem with early invasive disease is recognizing it and treating it supportively until the correct antibiotic can be chosen. I therefore rate it as about the same on the scariness scale as susceptible staph infections, invasive strep infections like toxic shock syndrome, or meningitis--the kind that kills teenagers. Very scary. But not very common.

A recent JAMA article (not permalinked, may expire) placed the incidence of invasive CA-MRSA infections at 3 to 5 per 100,000 by examining 7 LARGE areas--for example, the whole state of Connecticut. Compare that to the incidence (i.e., only new cases) of diabetes, now at over 7 per 1000, or 200 times more common than invasive CA-MRSA infections. And diabetes is less scary but, over the long run, still loaded with significant morbidity and mortality. It is the leading cause of limb amputations in the US.

What about mortality? The mortality rate from what I can tell for CA-MRSA is 0.5 per 100,000 in the JAMA study above. Heart disease mortality, by contrast, was from 239 to over 430 per 100,000 depending on demographics in the year 2000.

It may well be that resistant infections turn out to be the defining adversary of our generation in health care. For now, though, I wonder if they don't just make good news. Even the CDC, who quotes the rising rates for MRSA infections overall, doesn't advocate the closing of schools. Even if you could eradicate MRSA from all surfaces, I have a feeling it just might be back as soon as the kids return.

So--Purell kills MRSA--wash your hands. And keep living. Because, like it or not, this bug--which lives on everyone's skin, for crying out loud--isn't leaving.