What is the recommended treatment for bacillary dysentery?

Treatment for Bacillary Dysentery

Azithromycin is the first-line treatment for bacillary dysentery, with a recommended dosage of 1000 mg as a single dose or 500 mg daily for 3 days. 1, 2

Diagnostic Approach

• Bacillary dysentery (shigellosis) is characterized by bloody diarrhea, abdominal cramps, fever, and tenesmus
• When possible, stool specimens should be examined by microscopy to rule out amebic dysentery 1
• If microscopy is unavailable or trophozoites are not seen, patients with bloody diarrhea should be treated empirically for shigellosis 1

Treatment Algorithm

First-Line Treatment

• Azithromycin:
  • Adults: 1000 mg single dose OR 500 mg daily for 3 days 1, 2, 3
  • Children: Appropriate weight-based dosing

Alternative Options (Based on Local Susceptibility Patterns)

1. Fluoroquinolones (if local resistance patterns permit):

   • Ciprofloxacin: 500 mg twice daily for 3 days 1, 4, 5
   • Ofloxacin: 300 mg twice daily for 3 days 1
   • Levofloxacin: 500 mg once daily for 3 days 3

2. If resistance to above options is documented:

   • TMP-SMX (if susceptible): 160/800 mg twice daily for 3-5 days 1
   • Ampicillin (if susceptible): 500 mg four times daily for 5 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

Important Considerations

Antimicrobial Resistance

• Fluoroquinolone resistance is increasingly common, particularly in Southeast Asia and among Campylobacter species 1, 3
• Multidrug-resistant strains of Shigella are widespread 1, 6
• Periodic antibiotic susceptibility testing is advisable in endemic regions 1

Treatment Duration

• For immunocompetent patients: 3-5 days of therapy is typically sufficient 1
• For immunocompromised patients: Consider extending treatment to 7-10 days 1

Adjunctive Therapy

• Rehydration: Maintain adequate fluid intake; oral rehydration solutions for mild to moderate dehydration 1, 2
• Antimotility agents:
  • Traditionally contraindicated in dysentery
  • However, recent evidence suggests loperamide combined with effective antibiotics may be safe and can reduce duration of symptoms 4
  • Use with caution and only when combined with appropriate antibiotic therapy

Special Populations

• Children: Adjust antibiotic dosages appropriately based on weight
• Pregnant women: Azithromycin is preferred due to safety profile
• Immunocompromised: Longer treatment duration may be necessary 1

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 further evaluation 1
• Consider resistant shigellosis or alternative diagnoses such as amebiasis 1

Prevention Measures

• Proper handwashing and food safety practices
• Safe water consumption
• Proper sanitation and hygiene
• Food workers with diarrhea should be prohibited from working 1

Remember that antibiotic selection should be guided by local resistance patterns, and treatment should be promptly initiated to reduce the severity and duration of illness, as well as to prevent complications and further transmission.