Diarrhea, Acute (Community-Acquired)

PATHOGENS

Most common pathogens:

• Bacterial
  • Campylobacter jejuni
  • Salmonella species
  • E. coli: multiple classified by mechanism
    • Most important are enterotoxigenic (ETEC), enterohemorrhagic (EHEC) or Shiga toxin E. coli (STEC).
      • The most common STEC is E. coli 0157:H7
  • Shigella species
  • Yersinia spp. (non-plague)
  • Vibrio spp.
  • Cryptosporidia and Isospora
  • Listeria
  • E. histolytica
  • Plesiomonas shigelloides(controversial)
  • C. difficile
  • Aeromonas species (2% of traveler’s diarrhea, usually watery diarrhea with fever and abdominal cramps)
• Parasites: more typical to consider with diarrhea lasting > 14d (sub-acute or chronic).
  
  • Giardia
  • Entamoeba histolytica
  • Strongyloides stercoralis
• Viral:
  • Norovirus (a leading cause)
  • Adenovirus
  • Astrovirus
  • Coronavirus
  • Enterovirus
  • Calicivirus
  • Rotavirus

• Non-infectious causes: adverse drug reactions (e.g., antibiotic-associated), irritable bowel syndrome, inflammatory bowel disease (ulcerative colitis or Crohn’s disease), radiation or ischemic bowel disease, partial bowel obstruction, small bowel overgrowth, laxative abuse, collagen colitis, tube feeding and endocrine disorders among others.