When should antibiotics be prescribed for bacterial enteritis?

When to Prescribe Antibiotics for Enteritis

Antibiotics should NOT be routinely prescribed for most cases of enteritis, but are indicated for specific high-risk scenarios including bloody diarrhea with fever and systemic toxicity (presumed Shigella), immunocompromised patients with severe illness, infants <3 months with suspected bacterial etiology, and recent international travelers with fever ≥38.5°C or sepsis. 1

Watery Diarrhea (Non-Bloody)

Do not prescribe empiric antibiotics for acute watery diarrhea in immunocompetent patients without recent international travel 1

Exceptions for watery diarrhea:

• Immunocompromised patients who appear ill 1
• Young infants who are ill-appearing 1
• Avoid empiric treatment if watery diarrhea persists ≥14 days 1

Bloody Diarrhea (Dysentery)

Empiric antibiotics are NOT recommended for most immunocompetent patients with bloody diarrhea while awaiting culture results 1

Clear indications for empiric antibiotics in bloody diarrhea:

Treat immediately if:

• Infants <3 months with suspected bacterial etiology 1
• Bacillary dysentery syndrome (frequent scant bloody stools, fever, abdominal cramps, tenesmus) presumed to be Shigella 1
• Recent international travel with fever ≥38.5°C and/or signs of sepsis 1
• Immunocompromised patients with severe illness and bloody diarrhea 1

Empiric antibiotic choices:

Adults:

• Fluoroquinolone (ciprofloxacin) OR azithromycin, depending on local resistance patterns and travel history 1

Children:

• Third-generation cephalosporin for infants <3 months or those with neurologic involvement 1
• Azithromycin for others, based on local susceptibility and travel history 1, 2

Pathogen-Specific Considerations

Shigella

• Always treat proven or strongly suspected shigellosis promptly 3, 2
• Azithromycin is the preferred agent 3, 2

Salmonella

• Do NOT treat uncomplicated Salmonella gastroenteritis in healthy hosts 3, 4, 2
• Treat only severe cases or high-risk patients (infants, elderly, immunocompromised, those with prosthetic devices) 3, 2
• Use ceftriaxone or ciprofloxacin when treatment is indicated 2

Campylobacter

• Treat only if diagnosed early in the course 3, 2
• Azithromycin is preferred due to increasing fluoroquinolone resistance 2

STEC (Shiga toxin-producing E. coli)

• AVOID antibiotics for STEC O157 and other STEC producing Shiga toxin 2 (or unknown toxin genotype) 1
• Risk of precipitating hemolytic uremic syndrome 1

Enteric Fever (Typhoid/Paratyphoid)

Treat empirically if clinical features suggest enteric fever with sepsis 1

• Obtain blood, stool, and urine cultures first 1
• Use broad-spectrum therapy initially, then narrow based on susceptibilities 1

Critical Pitfalls to Avoid

• Never treat asymptomatic contacts empirically 1
• Do not use antibiotics for STEC infections producing Shiga toxin 2 1
• Avoid routine treatment of uncomplicated Salmonella in healthy hosts—this prolongs carriage 3, 4
• Timing matters: Empiric treatment is most effective when started within 48 hours of symptom onset in severely ill patients 5
• Consider non-infectious causes (IBD, IBS, lactose intolerance) if symptoms persist ≥14 days 1

Duration of Treatment

• Shigellosis: Short course (typically 3-5 days with azithromycin) 2
• Severe Salmonellosis: 7-14 days 2
• Campylobacter: 3-5 days if treated 2

Special Populations Requiring Lower Threshold

Consider antibiotics more readily in:

• Immunocompromised patients (HIV/AIDS, transplant recipients, chemotherapy) 1
• Infants <3 months of age 1
• Patients with prosthetic devices or valvular heart disease 3
• Sickle cell disease patients 2