Which genera of the Enterobacteriaceae are known to cause diarrhea and are considered enteric pathogens?

• A. Enterobacter, Klebsiella, Providencia, and Proteus
• B. Escherichia, Salmonella, Shigella, and Yersinia
• C. Pseudomonas, Moraxella, Acinetobacter, and Aeromonas
• D. Enterobacter, Citrobacter, and Morganella

Answer: (B)

The genera known to cause diarrhea and considered enteric pathogens include Escherichia, Salmonella, Shigella, and Yersinia. These organisms are specifically adapted to the gastrointestinal tract and are frequently associated with gastrointestinal infections.

Escherichia coli, particularly certain pathogenic strains such as E. coli O157:H7, are well-documented for causing foodborne illnesses characterized by diarrhea. Salmonella species are also major causes of gastroenteritis and can be transmitted through contaminated food and water. Shigella is known for causing bacillary dysentery, marked by severe diarrhea, and Yersinia enterocolitica can lead to gastroenteritis, particularly in children.

The other options include genera that do not primarily cause diarrhea or are not classified as enteric pathogens. The genera mentioned in the other choices may be associated with different types of infections but are not primarily linked with diarrheal disease caused by enteric bacterial pathogens. This makes the choice of Escherichia, Salmonella, Shigella, and Yersinia the correct response, as these are well-recognized enteric pathogens directly associated with diarrheal illnesses.