Probiotic Proves Deadly Against Clostridium Difficile

In the fight against bacterial pathogens, researchers are finding new weapons in “good” bacteria, as a new study suggests that probiotics may be used to kill dangerous Clostridium difficile bacteria.

According to the Centers for Disease Control and Prevention (CDC), the United States sees nearly 500,000 C. difficile infections each year. The “superbug” is one of the biggest drug-resistant threats plaguing the country’s healthcare system, killing an estimated 14,000 individuals each year and costing about $1 billion annually in medical expenses. C. difficile infections typically occur in individuals who have recently taken antibiotics to fight another infection, as the antibiotics kill off the beneficial bacteria in the gut and thus, make patients more susceptible to infection if they come into contact with contaminated surfaces. C. difficile spores can also be spread by healthcare workers’ hands. The pathogen leads to inflammation in the colon, and symptoms of an infection include watery diarrhea, fever, nausea, and loss of appetite; such infections are becoming increasingly drug-resistant and recurrent. In addition, more than 80% of deaths caused by C. difficile infections occur in adults who are 65 or older.

In a new study published in the journal Infection and Immunity, researchers from the Baylor College of Medicine examined how next generation probiotics can be used along with antibiotics to fight C. difficile. The study team identified the probiotic Lactobacillus reuteri as a candidate for adjunct therapy to be used with antibiotics such as vancomycin, metronidazole, and fidaxomicin against C. difficile.

“We wanted to find an alternative treatment, a prophylactic strategy based on probiotics that could help prevent C. difficile from thriving in the first place,” said the study’s lead author, Jennifer Spinler, PhD, in a recent news release.

The researchers studied the effects of L. reuteri on C. difficile grown in a laboratory, and found that when the probiotic was supplemented with glycerol, it converted it into the broad-spectrum antimicrobial compound reuterin. The reuterin acted as an antimicrobial agent, and worked as well as vancomycin to inhibit C. difficile growth. In addition, the researchers found that glycerol or L. reuteri alone were not effective against C. difficile, and that the reuterin did not harm the good bacteria in the complex gut community. "Probiotics are commonly used to treat a range of human diseases, yet clinical studies are generally fraught by variable clinical outcomes and protective mechanisms are poorly understood in patients,” explained senior author Tor Savidge, PhD. “This study provides important clues on why clinical efficacy may be seen in some patients treated with one probiotic bacterium but not with others.”

While the results are preliminary, the authors note that their findings suggest that the combination of L. reuteri and glycerol could be used as a novel treatment against C. difficile infections as well as preventatively in patients before they receive antibiotics. The new study is part of a growing body of research supporting the use of beneficial bacteria against antibiotic-resistant pathogens as an alternative to antibiotic drugs.