Antibiotic Resistance in Clostridioides difficile

C. difficile is a Gram-positive, spore-forming anaerobic and toxin-producing bacillus. It is the most common cause of nosocomial antibiotic-associated diarrhea and the etiologic agent of pseudomembranous colitis with about 453,000 cases and 29,000 deaths yearly in the U.S. as reported by CDC in 2015. Central to the predisposition to C. difficile infection (CDI) is the disruption of the gut microbiota by antibiotics. C. difficile is intrinsically resistant to a number of antibiotics used to treat other infections. Treatment of CDI usually involves oral metronidazole or vancomycin as first-line therapy. None of these is fully effective. Moreover, an estimated 15-35% of those infected with C. difficile relapse following treatment. The recently approved fidaxomicin has improved efficacy in preventing recurrence. However, the high cost of this antibiotic precludes its routine use. Treatment of recurrent CDI is one of the major challenges in the field. CDC has listed C. difficile as one of the top antibiotic-resistant threats in the 2013 report. More alarmingly, significantly decreased susceptibility to metronidazole and vancomycin has been reported. However, new trends of antibiotic resistance epidemiology and mechanisms involved in antibiotic resistance in C. difficile are under study.

The purpose of this Research Topic is to discuss recent advances in understanding antibiotic resistance mechanisms and new trends of antibiotic resistance epidemiology in C. difficile.

This Research Topic covers the following themes:
• Mechanisms involved in antibiotic resistance in C. difficile
• Epidemiology with regard to antibiotic resistance in C. difficile
• Novel therapies targeting antibiotic resistance in C. difficile