Drug Used For Deworming Could Stop Deadly C. Difficile Superbug Without Harming Healthy Gut Flora

The CDC calls C. difficile an “urgent threat” to public health, even though many in the general public may have never even heard of it. C. difficile, often called C. diff, is a bacteria that now causes half of a million infections a year in the United States and kills 15,000. In the United States, 29,000 patients died within 30 days of the initial diagnosis of C. difficile, and more than half of those patients died directly from their Clostridium difficile infection. The general public may not hear about C. diff as often as they hear about measles and mumps, but in the U.S., it’s silently killing thousands.

Antibiotics are often effective, but the CDC says that about 20 percent of patients treated for C. diff experience a recurrence of their symptoms thanks to the emergence of “hypervirulent” strains.

“1 out of every 5 patients with a healthcare-associated C. difficile infection experienced a recurrence of the infection and 1 out of every 9 patients aged 65 or older with a healthcare-associated C. difficile infection died within 30 days of diagnosis.”

Now, researchers from The Scripps Research Institute (TSRI) in San Diego say that some forms of deworming medications (salicylanilides) have been shown to stop the growth of numerous C. difficile strains. Earlier research into some salicylanilide anthelmintic drugs found the medications were shown to be potential weapons against the superbug MRSA, according to PLoS One.

Senior author Kim D. Janda, director of the Worm Institute for Research & Medicine, and the team at TSRI say that salicylanilides may be a handy weapon in the fight against C. difficile infection. Janda’s research was brought on by a personal battle with C. difficile infection. They figured out that a salicylanilide called closantel (a dewormer used in cattle, sheep, and goats) showed some effectiveness against the killer bacteria. More testing showed that three other salicylanilides (rafoxanide, niclosamide, and oxyclozanide) also showed effectiveness.

The deworming medications the team manipulated and tested even stopped a hypervirulent strain, and sometimes the dewormers were even more effective than the currently prescribed antibiotics, according to Medical News Today.

C. difficile strains with lessened susceptibility to metronidazole, vancomycin or fidaxomicin already exist. The salicylanilides, though, show “bactericidal activity against stationary-phase cultures of hypervirulent C. difficile–a property that is not exhibited by many antibiotics including metronidazole and vancomycin,” Scientific Reports explained. Stationary-phase cells make toxins that create toxins. The toxins trigger inflammation in the colon. In the hypervirulent strains of C. diff, the cells can be active enough to lead to death. These cells even make what Medical News Today calls “spores” that can survive on toilets, sinks, and other surfaces.

The researchers think that the deworming drugs may modify the electrical properties of the C. diff‘s membrane. When they modified the dewormers so the membrane-altering effects were greater, the dewormers had an even greater ability to stop the growth of the C. difficile.

Perhaps the best thing about these altered deworming medicines is that they appear to have very little impact on the gut bacteria that benefits human health, and C. difficile does not seem to be able to develop resistance to it.

The team is now testing the adapted deworming drugs on animal models of C. difficile infections, and negotiations to license the salicylanilides to a pharmaceutical company are underway, according to a press release.

[Image by corgaasbeek/ Pixabay]