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Acute infectious diarrhea in adults

IDSA-based assessment, rehydration, selective stool testing and antibiotic stewardship for acute diarrhea in US and travel settings.

JurisdictionUnited States
Source check2026-08-20
Clinical reviewiatroX editorial team 路 Clinical editorial review 路 reviewed 2026-08-20 路 due 2027-08-20
AudienceUnited States healthcare professionals
This is an iatroX educational summary of named United States sources, not an official guideline. It does not replace the complete source documents, local policy, specialist advice or clinical judgement. Use the named authority, current FDA labeling, applicable state law, payer rules and local protocol where relevant.

Scope of this summary

Adults with acute diarrhea likely to be infectious. The IDSA guideline covers adults and children; this page is bounded to adult ambulatory and emergency recognition. Clostridioides difficile, persistent diarrhea, inflammatory bowel disease, immunocompromised hosts, pregnancy and outbreak control require additional source-specific guidance.
sources for this section:IDSA infectious diarrhea 2017

The Bottom Line

  • Assess dehydration and replace fluid first, using oral rehydration solution for mild to moderate dehydration and isotonic intravenous crystalloid for shock, severe dehydration, altered mental status or failed oral therapy.
  • Test stool for major bacterial pathogens, Shiga toxin and C. difficile when diarrhea includes fever, blood or mucus, severe abdominal tenderness or sepsis features; broaden testing from travel, immune status and outbreak exposure.
  • Avoid routine stool testing and antibiotics for most short, uncomplicated watery diarrhea because supportive care is usually sufficient and unnecessary treatment causes adverse effects and resistance.
  • Do not give antibiotics when Shiga-toxin-producing Escherichia coli O157 or a strain producing Shiga toxin 2 is suspected or confirmed because treatment can increase harm.
  • Use exposure history鈥攖ravel, food, untreated water, animal contact, sexual exposure, healthcare, antibiotics and sick contacts鈥攖o guide the organism, public-health and infection-control pathway.
sources for this section:IDSA infectious diarrhea 2017

Practical clinical workflow

1
Record onset, frequency, volume, blood, fever, vomiting, urine output, travel, food and water, antibiotics, healthcare, immunosuppression and shared illness; assess orthostasis, mucosa, perfusion and abdominal signs.
2
Start oral rehydration and continued age-appropriate nutrition when safe; correct electrolyte and glucose disturbances and avoid antimotility medicine in inflammatory diarrhea or toxic illness.
3
Order targeted stool molecular or culture testing for severe, inflammatory, persistent, outbreak-associated or high-risk disease; understand that multiplex detection may require culture for susceptibility and public health.
4
Use empiric antibiotic only in the limited source-defined situations, considering travel region, resistance, immune status and sepsis; narrow or stop treatment when the organism and susceptibility are known.
5
Give clear return advice, report notifiable infection, exclude high-risk food handling or healthcare work under local rules and reassess persistent symptoms for parasites, postinfectious illness or a noninfectious diagnosis.
sources for this section:IDSA infectious diarrhea 2017

Safety boundaries and escalation

  • Shock, severe dehydration, confusion, oliguria, peritonitis, toxic megacolon, severe sepsis or inability to maintain oral hydration requires emergency assessment.
  • Bloody diarrhea with severe abdominal pain and little fever can indicate Shiga-toxin-producing E. coli; avoid antibiotics and antimotility agents while urgent diagnostic and renal monitoring proceeds.
  • Monitor for hemolytic uremic syndrome with falling hemoglobin or platelets, rising creatinine or reduced urine after diarrheal illness, and arrange immediate hospital care.
  • Older adults, pregnant patients, immunocompromised people and those with major comorbidity have lower thresholds for testing and escalation; generic traveler treatment is not sufficient.
sources for this section:IDSA infectious diarrhea 2017

Localization

US state and local health departments determine reporting, outbreak testing and work exclusion. Use current CDC travel notices and local antimicrobial resistance with the IDSA guideline.
sources for this section:IDSA infectious diarrhea 2017

Source documents

Use the linked source documents for complete recommendations, evidence grading, exclusions and implementation detail.

  1. Infectious Diseases Society of America2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious DiarrheaDOI 10.1093/cid/cix669 路 published 2017-10-19 路 accessed 2026-08-20
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