What is the recommended treatment for Shigella infections?

Recommended Treatment for Shigella Infections

For Shigella infections, ciprofloxacin is the first-line treatment for adults (500 mg twice daily for 3-7 days), while azithromycin is preferred for children (10 mg/kg on day 1, followed by 5 mg/kg once daily for 4 days). 1

Treatment Recommendations by Population

Adults

• First-line: Ciprofloxacin 500 mg twice daily for 3-7 days 1
• Alternative options:
  • Trimethoprim-sulfamethoxazole (TMP-SMX) 160 mg TMP and 800 mg SMX twice daily for 5 days 1, 2
  • Azithromycin 500 mg once daily for 3 days 1
  • Nalidixic acid 55 mg/kg/day in four divided doses for 5 days 1
  • Tetracycline 50 mg/kg/day in four divided doses for 5 days 1

Children

• First-line: Azithromycin 10 mg/kg on day 1, followed by 5 mg/kg once daily for 4 days 1
• Alternative option: Ceftriaxone 1
• Note: Fluoroquinolones are not first-line for children due to concerns about arthropathy, though they can be used when necessary 1
• TMP-SMX dosing for children: 40 mg/kg sulfamethoxazole and 8 mg/kg trimethoprim per 24 hours, given in two divided doses every 12 hours for 5 days 2

Special Populations

Immunocompromised Patients

• HIV-infected patients may require extended treatment for up to 14 days 1
• Patients with bacteremia may also need extended treatment for up to 14 days 1

Food Handlers and Healthcare Workers

• May require follow-up stool culture to ensure clearance before returning to work 1

Treatment Considerations

Antibiotic Resistance

• Multiresistant strains of Shigella are widespread globally 1
• High rates of resistance to ampicillin and TMP-SMX have been reported 1
• Increasing resistance to fluoroquinolones observed in some regions 1, 3
• Ciprofloxacin remains effective in many regions with resistance rates as low as 2.6-7% across different Shigella species 3

Treatment Failure

• If no clinical response occurs within 2 days, change to another recommended antibiotic 1
• If no improvement after an additional 2 days, refer for stool microscopy 1

Practical Treatment Algorithm

1. Identify patient age and risk factors
2. For adults:
   • Start ciprofloxacin 500 mg twice daily for 3-7 days
   • If contraindicated or unavailable, use azithromycin or TMP-SMX
3. For children:
   • Start azithromycin 10 mg/kg on day 1, followed by 5 mg/kg once daily for 4 days
   • If contraindicated or unavailable, consider ceftriaxone
4. Monitor response:
   • Assess for clinical improvement within 48 hours
   • If no improvement, switch to alternative antibiotic
5. Special considerations:
   • Extend treatment duration for immunocompromised patients or those with bacteremia
   • Consider local resistance patterns when selecting empiric therapy

Important Caveats

• Mass prophylaxis or prophylaxis of family members is not recommended 1
• Local susceptibility patterns should guide therapy choice, particularly for empiric treatment 1
• Antibiotics should be avoided for STEC O157 and other Shiga toxin 2-producing E. coli infections, as antimicrobial therapy may increase the risk of hemolytic uremic syndrome (HUS) 1
• Despite concerns about arthropathy with fluoroquinolones in children, studies have shown ciprofloxacin to be safe and effective in pediatric shigellosis when necessary 4