Salicylanilides, a class of drugs often used in animals to kill parasitic worms, may be an effective tool to combat strains of Clostridium difficile that are resistant to antibiotics and cause thousands of frequently fatal hospital infections annually, according to a new study from The Scripps Research Institute in La Jolla, Calif.
"These salicylanilide compounds have all the right features, and they've long been used in animals, so I think they can be quickly repurposed against C. difficile infections in people," senior author Kim D. Janda, PhD, said in a statement. Even when antibiotics are viable to use against a C. diff strain about one in seven patients will experience a recurrent infection.
Dr. Janda said the discovery came about almost by accident when his institute researched effective C. diff treatments using salicylanilides as a control. Once the team noticed how effective this class of drugs was, they expanded testing to investigate the efficacy of other anti-worm drugs and isolated a number of them that inhibited C. diff growth to a degree that rivals the antibiotics traditionally used to fight it. Two salicylanilides — closantel and rafoxanide — were effective against a non-growing form of C. diff. The researchers say this finding was important because the most toxins and inflammation are produced during this stationary phase of cell growth.
The research team also created new salicylanilides as part of their study, one of which they plan to license to a pharmaceutical company for new drug development.