C. diff Epidemic: What You Must Know
Why C. diff Is Spreading, Why It's More Deadly, How to Protect Your Family
WebMD News Archive
Can you get C. diff from food?
There's troubling evidence that at least a few cases come from food. There are two reasons to think this might happen:
- In 2005, Canadian researchers bought 53 packages of beef and seven packages of veal from five grocery stores in Ontario and in Quebec. One out of five packages carried C. diff. Two-thirds of the C. diff isolates were similar to the NAP1 strain.
- C. diff isolates from human patients are quite similar to isolates found in pigs and cattle. Some of the pig isolates are almost indistinguishable from human isolates.
The CDC's McDonald says there is "at least the appearance" of "migration" of strains epidemic in food-producing animals to humans. That's because the animal epidemics occurred before the human epidemic.
"We think that direct transmission from animals to humans via the food supply, IF it occurs at all -- no one has proven this -- would account for a very small proportion of overall human C. diff infection," McDonald writes in an email to WebMD.
The CDC, together with academic researchers, is culturing samples of retail meats; results of these studies are expected soon. Eventually the CDC will look at dietary risk factors associated with community-acquired C. diff infection.
Even if you can get C. diff from food, the vast majority of infections come from person-to-person transmission (see below).
How do you get C. diff?
Even many health care professionals wrongly think everyone carries C. diff in their intestines and that the bug only overgrows when antibiotic therapy or illness disrupts the normal gut ecology and gives it room to grow.
That's not the case. Only 5% of the population is "colonized" by C. diff. And because population studies have only looked at one point in time, even most of these people may only be having a temporary infection.
Even so, more than half of Americans show evidence of a previous C. diff infection some time in their lives. This often happens soon after birth. But infants only rarely get C. diff disease. The reason for this isn't clear, but there's evidence from animal models that C. diff toxins have trouble binding to the immature gut.
C. diff bacteria are very sensitive to oxygen. But C. diff spores are another matter. They are nearly indestructible and can survive for months on dry surfaces. The CDC recommends disinfecting surfaces with bleach, because the usual hospital disinfectants don't affect it.
People with C. diff infection have millions of C. diff spores in their feces. These spores carry the infection to others via what experts indelicately call fecal-oral contact. Careful hand washing rinses the spores from contaminated hands, but alcohol gels won't do the trick.
Two things have to happen for you to get C. diff disease:
- You have to ingest C. diff spores.
- Something has to disturb the ecological balance of the normal bacteria living in your colon.