Clostridioides difficile (C. difficile) is a bacterium that can infect the large intestine, with symptoms ranging from diarrhea to life-threatening colon damage. A study published May 11 in PLOS Biology by Ophelia Venturelli at University of Wisconsin-Madison, U.S., and colleagues suggests that between-species interactions within the gut microbiome may impact the efficacy of antibiotics aimed at treating C. difficile infections.