Which bacteria are commonly associated with antibiotic-associated diarrhea?

Clostridium difficile is the bacterium most commonly associated with antibiotic-associated diarrhea. This association is primarily due to the antibiotic-induced disruption of normal intestinal flora, which allows C. difficile to proliferate and produce toxins that lead to diarrhea.

When antibiotics are taken, they can decrease the diversity of gut microbiota, including beneficial bacteria that help keep C. difficile in check. In cases of overgrowth, the toxins produced by C. difficile can cause inflammation of the intestinal lining, resulting in symptoms ranging from mild diarrhea to severe colitis.

While other bacteria listed may also cause gastrointestinal symptoms under different circumstances, they are not typically linked to antibiotic-associated diarrhea in the same way as C. difficile. Bacillus cereus may cause foodborne illnesses, Escherichia coli includes various strains that can lead to different types of infections, and Salmonella enterica is often associated with foodborne illness as well. However, they do not have the specific association with antibiotic-induced changes in the gut flora that C. difficile exhibits.