Fixing the microbiota to treat Clostridium difficile infections

Despite the existence of numerous antibiotics, recurrence of certain infections, such as those caused by Clostridium difficile, remains a clinical challenge. The root of the problem is the detrimental effect of antibiotics on the function and composition of intestinal commensals. To tackle C. difficile refractoriness to treatment and infection recurrence, scientists are trying to understand how a healthy microbiota may keep this pathogen at bay to identify the microbial contributors of protection and to develop targeted probiotic-based therapies. In 'Bedside to Bench', Ying Taur and Eric Pamer discuss the potential of fecal microbiota transplantation (FMT) and peruse mechanisms to explain its efficacy. Alteration of bile salts, which are involved in germination of C. difficile spores, by the healthy microbiota may explain why microbiome depletion upon antibiotic treatment can lead to pathogen overgrowth. In 'Bench to Bedside', Ruth Ley peruses a recent study suggesting that sialic acids increasingly released by gut commensals after antibiotic treatment may play a crucial part in boosting C. difficile growth. Starving the pathogen of this carbohydrate in the gut by FMT or, more specifically, with engineered probiotics that can outcompete the pathogen for sialic acids may prove effective to treat or even prevent C. difficile infection.