Mike the Mad Biologist

So I was at the ASM meeting last week, and one of the talks I heard was by Kim Ware about Clostridium difficile infection control: how one hospital learned to contain and prevent outbreaks (Note: these are from my notes; I haven’t downloaded the presentation yet). C. difficile is a bacterium that causes diarrhea and more serious intestinal conditions such as colitis. It is often associated with antibiotic therapy and stays in healthcare environments: this is primarily a ‘hospital disease.’ While most cases result in diarrhea (which isn’t trivial if you’re already very sick), eleven percent of cases lead to severe cases that can result in removal of the colon or even death.

The economic costs are considerable. According to Ware, the average cost of treating an infection is between $2,500-$7,500. In the U.S., there are several thousand patient deaths annually in the U.S. associated with C. difficile.

When I write that C. difficile (‘CD’) is a healthcare-associated disease, some data explain what I mean. According to Ware, in hospitals where less than a quarter of environmental samples (e.g., counter swipes) are positive for CD, no staff (yes, staff) carry CD on their hands. When more than fifty percent of environmental samples test positive, a third of staff carry CD on their hands. We also know that there is a positive feedback between CD patients and increased CD disease: even with ‘strict’ isolation, patients still are transported all over the hospital (and staff, despite precautions, are more likely to carry CD).

Since it’s primarily a healthcare-associated disease, and most healthcare institutions try not to kill their patients, there’s been a lot of study about the practices hospitals should use and the practices they do use. Sadly, these two sets don’t overlap as much as one would like. The best strategy to date is a tiered approach, which has two categories of precautions: routine and outbreak/heightened. Routine precautions entail the following*:

•Private rooms for CD patients (to the extent possible). Older hospitals often don’t have this capacity.
•’Special’ CD patient bathrooms (CD is found in feces).
•Dedicated equipment for CD patients. Don’t use the same rectal probes–I’m not kidding. Really. I’m not kidding.
•All personnel must wear gowns and gloves upon entry into the patient’s room (or CD ward). Despite beliefs to the contrary, staff will touch surfaces in the room, and pick up CD.
•Don’t use bleach to clean surfaces (by the way, studies show that only half of high-contact surfaces are reguarly cleaned…).
•Soap and water for hand washing is recommended, but not required. After all, we isolate CD by suspending stool in 95% ethanol (which kills off the other bacteria)–what is a 65% hand solution going to do?
•Once CD is not detected once and there is no diarrhea for 48 hours, patients can be treated as ‘cleared.’

Under outbreak or heightened CD conditions (how we determine that in a little bit), the following additional measures were adopted:

•Soap and water for handwashing is required. Incidentally, Ware’s team discovered that they had to put up signs altering staff to do this, otherwise they didn’t know they had to do this.
•All diarrhea cases are presumed to be CD and isolated.
•Bleach is used. This was very interesting. Only a ten percent bleach solution should be used. More bleach doesn’t disinfect any better, but it does cause respiratory distress in some critical patients. Also, bleach is really bad at cleaning things. The staff need to be alerted that they have to clean surfaces and then disinfect them.
•All visitors, including family, must wear gloves and gowns.
•Patients should have private rooms.

So how does a hospital know when it has to adopt outbreak measures? Surveillance, surveillance, surveillance (and then more surveillance). And surveillance doesn’t just mean more cases of CD observed in the microbiology lab. It also means monitoring diarrheal cases and colectomies: increases in either could mean a CD outbreak. Amazingly, most hospitals don’t keep track of these. Also, the staff need to help the surveillance efforts. For instance, stool samples shouldn’t be left out at room temperature for hours, but need to be refrigerated–leading to the slogan “Cool your stool.” (Again, not kidding). Staff should also know what the lab can and can’t use. Said Ware, “If it’s moon rocks or rolls around in the cup, I don’t what to test it.”

There are a couple of unresolved issues. First, should nurses be able to order CD tests without physician approval? Second, given the importance of handwashing, facilities need to make it easier to get to a sink (a few feet can make a big difference). Third, public reporting should be mandatory, but most legislators aren’t familiar with CD–they need to be educated about the disease.

Anyway, that’s what I learned about CD, to the best of my recollection. Discuss.

*Different organizations have different guidelines. I’m describing what Ware adopted and instituted in other hospitals in Maine.

Comments

  1. #1 cicely
    June 1, 2010

    Is this clostridium what causes ulcerative colitis, or is that caused by something else?

  2. #2 cicely
    June 1, 2010

    *sigh* Tag-closure fail.

  3. #3 JohnV
    June 1, 2010

    Cicely I double checked this in pubmed. Short answer is “I don’t think so”. Long answer:

    I was familiar with C. difficile causing pseudomembranous colitis (575 refs for difficile and “pseudomembranous colitis”). I checked for difficile and “ulcerative colitis” and got 118 refs. If you leave the quotes out it goes to ~2360 and 123.

    The papers with “ulcerative colitis” hits didn’t seem to be of the “C. difficile causes ulcerative colitis” nature. A number of them talk about C. difficile showing up in inflammatory bowel disease. But I’m too lazy to look into IBD.

    Also since I’m flexing my clostridial knowledge, I’d like to nitpick this quoted statement “After all, we isolate CD by suspending stool in 95% ethanol (which kills off the other bacteria)–what is a 65% hand solution going to do?”

    In fact, 95% ethanol probably does kill C. difficile vegetative cells, just like its killing all the other vegetative cells. You’re just left with spores of all the Clostridia in the gut persisting in the ethanol. (although in patho lab I taught in and the C. perfringens lab I worked in we always used 70% and not 95% for some arcane reason about its sterilization ability). And also to pimp the microbe that I rode to a PhD, enterotoxin-producing strains are also implicated in nosocomial diarrhea, although with much less severe outcomes that are typical of the C. difficile 027 ribotype epidemic.

  4. #4 Steve
    June 2, 2010

    I work for a British bio-decontamination company and our experiences here sound similar. Our problem is getting into patient areas to decontaminate the environment as our traditional hospital design tends to be 6 bed bays and siderooms. We don’t use bleach, we use hydrogen peroxide vapour generators and it kills everything in the deployed area. We have done some studies in the USA. Check our website, http://www.bioquell.com

  5. #5 cicely
    June 2, 2010

    Thanks, JohnV. :)

  6. #6 JohnV
    June 4, 2010

    You’re welcome, my knowledge doesn’t come in handy very often :P

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