Although the highest morbidity and mortality occurs in low- to middle-income nations, infectious diarrhea accounts for approximately 180 million illnesses annually in the US, according to a recent clinical guideline developed by the Infectious Disease Society of America (IDSA). Risk factors such as international travel, antibiotic use, child care settings, and exposure to animals modify the potential pathogens, for which there may be nuanced differences in testing and management recommendations. Key recommendations in this guideline—which targets infants, children, adolescents, and adults in the US with acute or persistent infectious diarrhea—include:

• Test stool for bacterial pathogens in patients with fever, bloody or mucoid stools, severe abdominal cramping or tenderness, or signs of sepsis.
• Avoid antimicrobials for most patients with acute watery diarrhea or bloody diarrhea who are healthy and age ≥3 months.
• Avoid antimicrobials for patients with Escherichia coli O157 or Shiga toxin 2–producing organisms or if the toxin genotype is unknown.
• Use reduced-osmolarity oral rehydration solution (ORS) as first-line therapy for mild to moderate dehydration, even with vomiting.
• Administer isotonic intravenous fluids for severe dehydration, shock, or altered mental status and failure of ORS therapy or ileus.
• Oral zinc supplementation reduces the duration of diarrhea in children age 6 months to 5 years who may have a zinc deficiency.
• Report all nationally notifiable organisms to territorial, state, or local health departments to ensure infection control and prevention practices.