What is the recommended treatment for Shigella infections?

Treatment of Shigella Infections

For Shigella infections, azithromycin is the first-line treatment of choice, with ciprofloxacin as an alternative depending on local susceptibility patterns. 1

First-Line Treatment Options

Adults:

• Azithromycin (first choice) 1
• Ciprofloxacin (alternative): 500 mg twice daily for 5 days 1, 2
• TMP-SMX: 160 mg TMP and 800 mg SMX twice daily for 5 days (if susceptible) 1

Children:

• Azithromycin (first choice) 1, 3
• Ceftriaxone (especially for infants <3 months or with neurologic involvement) 1
• TMP-SMX: 10 mg/kg/day TMP and 50 mg/kg/day SMX in two divided doses for 5 days (if susceptible) 1

Treatment Algorithm

1. Initial assessment:

   • Evaluate for dehydration (highest priority for reducing mortality) 1
   • Check for fever, bloody or mucoid stools, and abdominal pain 1
   • Assess for signs of sepsis or systemic illness 1

2. Laboratory confirmation:

   • Stool culture and susceptibility testing when possible 1
   • Test for Shiga toxin if bloody diarrhea is present 1

3. Treatment initiation:

   • For mild-moderate disease: Begin antimicrobial therapy based on local susceptibility patterns
   • For severe disease: Consider hospitalization and parenteral therapy

4. Treatment monitoring:

   • If no clinical response within 2 days, change to an alternative antibiotic 1
   • If no improvement after an additional 2 days, consider referral for stool microscopy to rule out resistant shigellosis or amebiasis 1

Special Considerations

Antimicrobial Resistance

Resistance to traditional antibiotics is increasingly common in Shigella species 4:

• Avoid fluoroquinolones if ciprofloxacin MIC is ≥0.12 μg/mL even if reported as susceptible 1
• Periodic susceptibility testing is advisable due to rapidly emerging resistance 1

Immunocompromised Patients

• HIV-infected patients should receive treatment for all Shigella infections due to higher risk of bacteremia 1
• Longer treatment courses (7-14 days) may be needed for immunocompromised patients 1

Contraindications

• Antimotility agents are contraindicated in shigellosis 5
• Mass prophylaxis or prophylaxis of family members is not recommended 1

Supportive Care

• Rehydration: Critical for preventing complications and death, especially in young children and elderly 1
• Electrolyte management: Monitor and correct imbalances 1
• Nutritional support: Continued feeding during and after shigellosis is important 5

Common Pitfalls to Avoid

1. Delaying treatment: Appropriate antimicrobial therapy decreases severity, duration of illness, and pathogen excretion 1

2. Overuse of fluoroquinolones: Despite effectiveness, fluoroquinolones should be used judiciously due to increasing resistance 4

3. Inadequate follow-up: If symptoms persist after initial therapy, reevaluate for resistant organisms or alternative diagnoses 1

4. Ignoring local resistance patterns: Treatment should be guided by local susceptibility data whenever possible 1

5. Failure to consider Shiga toxin: When treating bloody diarrhea, test for Shiga toxin to rule out STEC, as antimicrobial therapy is contraindicated in STEC infections 1

The evidence strongly supports prompt antimicrobial treatment for Shigella infections to reduce morbidity, mortality, and transmission. The choice of antibiotic should be guided by local susceptibility patterns, with azithromycin and ciprofloxacin being the most recommended options in current guidelines.