A Clostridium difficile -Specific, Gel-Forming Protein Required for Optimal Spore Germination

The spore-forming bacterium Clostridium difficile is a leading cause of health care-associated infections. While a subset of antibiotics can treat C. difficile infections (CDIs), the primary determinant of CDI disease susceptibility is prior antibiotic exposure, since it reduces the colonization resistance conferred by a diverse microflora. Thus, therapies that minimize perturbations to the gut microbiome should be more effective at reducing CDIs and their recurrence, the main source of disease complications. Given that spore germination is essential for C. difficile to initiate infection and that C. difficile uses a unique pathway to initiate germination, methods that inhibit distinct elements of germination could selectively prevent C. difficile disease recurrence. Here, we identify GerG as a C. difficile-specific protein that controls the incorporation of germinant signaling proteins into spores. Since gerG mutant spores exhibit germination defects and are less responsive to germinant, GerG may represent a promising target for developing therapeutics against CDI.