Spore Wars Help Fend Off Life-Threatening Bacterial Infections

C. difficile bacteria, shown in yellow, are common in hospitals and nursing homes, and very difficult to treat. (Science Source)
C. difficile bacteria, shown in yellow, are common in hospitals and nursing homes, and very difficult to treat. (Science Source)

Infections with the bacteria Clostridium difficile are a big problem, killing 29,000 people a year. Many of those people got infected while in the hospital. And antibiotics often don't work.

So how about this: Take spores from a harmless version of C. difficile and use them to fight off the bad bugs?

That's just what researchers at the VA hospital in Hines, Ill., did.

The concept had been tried decades ago in mice, but it took at lot of time and testing to figure out which strains were truly harmless in humans while still being tough enough to beat up on the nasty strains.

"The key thing here is being able to use a spore-forming bacteria," says Dr. Dale Gerding, a researcher at the Veterans Administration who has spent his career trying to come up with effective treatments for C. difficile. Not only are spores a lot easier to manage, they survive the trip through stomach acid to the gut where C. difficule wreaks its havoc, causing debilitating diarrhea and nausea.

Then the researchers had to find a company to turn the concept into a treatment. "That was quite a struggle," Gerding says. "It took about 10 years."

Spore treatment in hand, Gerding and colleagues tested it in 157 people who had recently had a bout of C. difficile. Half of them took the spores in a water solution, and the other half took a watery placebo. Eleven percent of people given spores became reinfected with C. difficile, compared to 30 percent of the people on placebo. Sixty percent of the placebo patients had at least one more bout of diarrhea, compared to 46 percent of spore-takers.

The results were reported Tuesday in JAMA, the journal of the American Medical Association.

Preventing recurrent infections would be great because they're so common, but Gerding says the real dream would be to prevent getting infected at all. "Basically, beat the toxigenic strain to the patients and keep them from getting C. difficle in the hospital."

This was a Phase 2 study to test the treatment's effectiveness and safety, so it would have to be tested on more people and compared to existing treatments before it could be approved by the Food and Drug Administration.

This is just one form of biotherapy that's being tried for C. difficile. Another is fecal transplants — giving a sick person an infusion of fecal matter from a healthy person, so that the healthy bacteria nudge out the bad.

Fecal transplants do work for people with recurrent C. difficile infections, according to a review of research published Monday. But the reviewers found just two randomized controlled trials testing the therapy. That's not much of a track record, and they didn't look at whether fecal transplants would work to on initial infections, or whether differences in donors or techniques matter. The study was published in Annals of Internal Medicine.

But fecal transplants have their downsides; they're complicated and have a substantial "ick" factor. Here's one workaround: frozen poop pills.

Last fall we reported on efforts at Massachusetts General Hospital to test the poop pill concept. They filled capsules with fecal contributions from healthy volunteers and gave them to 20 people with recurring C. diff infections. The pills worked immediately for 14 of the patients. Four more got relief by taking another two-day course of the pills.

Some researchers are experimenting with freeze-dried poop pills, which would be easier to store and transport than the frozen versions.

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