Antibiotic Use in Diarrhea

Patient Selection

• The Infectious Diseases Society of America recommends prescribing antibiotics in diarrhea only when there is evidence of invasive bacterial infection, documented fever >38.5°C, symptoms of dysentery, or in immunocompromised patients with severe disease 1
• Antibiotics should be considered in infants under 3 months with suspected bacterial etiology, immunocompromised patients with severe disease and bloody diarrhea, patients with suspected bacillary dysentery, recent international travelers with a body temperature ≥38.5°C and/or signs of sepsis, and patients with suspected typhoid fever and clinical signs of sepsis 1
• Asymptomatic contacts of individuals with bloody diarrhea should be considered for antibiotic treatment, while patients with STEC O157 and other STEC producing Shiga toxin 2 infections should not be treated with antibiotics due to the increased risk of hemolytic uremic syndrome 1

Treatment

• The Infectious Diseases Society of America recommends azithromycin as the first option for children and in areas with fluoroquinolone resistance, while azithromycin should not be used as a first-line treatment for acute watery diarrhea in immunocompetent patients 1
• Antidiarrheal agents like loperamide should be avoided in patients with bloody or inflammatory diarrhea, and antibiotics should not be used in STEC infections producing Shiga toxin 2 1

• The following antibiotic therapies are recommended:

  | Type of Diarrhea | Recommended Antibiotic Therapy | | --- | --- | | Severe diarrhea | Azithromycin | | Cholera | Azithromycin | | Invasive bacterial diarrhea | Azithromycin or fluoroquinolones | | C. difficile infection | Vancomycin or fidaxomicin | | STEC infections | No antibiotic therapy recommended | 2, 3, 4, 5

  Management

• The Infectious Diseases Society of America recommends oral rehydration solution with reduced osmolarity as the first-line treatment for mild to moderate dehydration, and treatment should be adjusted or suspended when a clinically plausible organism is identified 1
• Patients should be reevaluated if symptoms persist, including assessment of fluid and electrolyte balance, nutritional status, and optimal dose and duration of antimicrobial therapy 1
• The American Gastroenterological Association recommends maintaining adequate fluid intake with glucose-containing fluids and electrolyte-rich soups, while the American Society of Clinical Oncology suggests eliminating lactose-containing products and high-osmolar dietary supplements 6, 7
• Loperamide can be used at 4 mg initially, then 2 mg every 4 hours or after each unformed stool (maximum 16 mg/day), but should be discontinued after being diarrhea-free for at least 12 hours and is contraindicated in patients with bloody diarrhea, suspected inflammatory diarrhea, and children under 18 years 7, 1, 2, 8
• Vancomycin and metronidazole can be used as first-line treatments for certain infections, with dosages and administration routes varying depending on the patient's condition and ability to take oral medications 9
• The Infectious Diseases Society of America recommends limiting antibiotic therapy to 4-7 days, and in many cases, single doses or short courses of 3 days are sufficient 10

Monitoring and Prevention

• Warning signs and symptoms include fever >38.5°C, severe abdominal pain, bloody stools, signs of dehydration, and leukocytosis >15×10⁹/L, and patients should be monitored for frequency and consistency of stools, vital signs, fluid balance, weight, and serum electrolytes 9, 1, 8
• Antiperistaltic agents should be avoided in suspected inflammatory or infectious diarrhea, and levofloxacin and other antibiotics should be avoided in patients with STEC infections that produce Shiga toxin 2 due to the increased risk of hemolytic uremic syndrome 9, 1
• Indiscriminate use of antibiotics should be avoided to prevent antimicrobial resistance and antibiotic-associated diarrhea, including C. difficile infection, and good hand hygiene should be maintained to prevent C. difficile transmission 7
• Surgery is only indicated for perforation or ischemia, and patients should be monitored for indications for surgical intervention, such as persistent GI bleeding, free intraperitoneal perforation, abscess formation, or clinical deterioration 11, 8, 1
• Probiotics can be considered to reduce the duration and severity of symptoms, although the strength of evidence is moderate, and neutropenic enterocolitis requires prompt recognition and treatment, including bowel rest, nasogastric decompression, and serial abdominal examinations 2, 8, 1