What is the first-line antibiotic for enteritis?

First-Line Antibiotic Treatment for Enteritis

For mild to moderate enteritis, amoxicillin-clavulanic acid is the first-line antibiotic treatment, while azithromycin is recommended for severe cases or when fluoroquinolone-resistant pathogens are suspected. 1, 2

Treatment Algorithm Based on Severity

Mild to Moderate Enteritis

• Amoxicillin-clavulanic acid as first-line therapy 1
• Alternative options:
  • Ampicillin + gentamicin + metronidazole 1
  • Ciprofloxacin + metronidazole (second choice due to resistance concerns) 1

Severe Enteritis

• Azithromycin 500 mg daily for 2-5 days (IV initially, then oral when tolerated) 2
• Alternative options:
  • Cefotaxime or ceftriaxone + metronidazole 1
  • Piperacillin-tazobactam for more severe cases 1

Pathogen-Specific Considerations

When Campylobacter is Suspected/Confirmed

• Azithromycin is superior to fluoroquinolones with 100% clinical and bacteriological cure rates in areas with high fluoroquinolone resistance 2, 3
• Single dose 500 mg for acute watery diarrhea or 1000 mg for dysentery 3

When Shigella is Suspected/Confirmed

• Azithromycin demonstrates effective cure rates 2
• Ceftriaxone is more effective than fluoroquinolones for confirmed Shigella infections 1

When Salmonella (Enteric Fever) is Suspected/Confirmed

• Azithromycin shows lower risk of clinical failure (OR 0.48) and shorter hospital stays compared to fluoroquinolones 4
• Azithromycin or ceftriaxone is first-line for quinolone-resistant strains 4

Special Considerations

Antibiotic Resistance Patterns

• Fluoroquinolone resistance is increasingly common worldwide, particularly among Campylobacter species 2, 3
• Ciprofloxacin resistance was detected in 4% of Campylobacter strains in one study 5
• Local resistance patterns should guide empiric therapy choices 1

When to Use Antibiotics

• Most viral and mild bacterial gastroenteritis cases do not require antibiotic treatment 2
• Antibiotic treatment is warranted for:
  • Severe symptoms (dysentery or incapacitating diarrhea) 2, 3
  • Immunocompromised patients 1
  • Patients with prostheses or valvular heart disease 1

Combination Therapy

• Loperamide in combination with antibiotic treatment can further reduce gastrointestinal symptoms and duration of illness 3
• For intra-abdominal infections, metronidazole should be added to cephalosporins to provide anaerobic coverage 1

Clinical Pearls and Pitfalls

• Bacterial confirmation should ideally be obtained before treatment, but empiric therapy is warranted in severe cases 2
• Antibiotic treatment significantly reduces symptom severity and duration of illness in bacterial enteritis 3
• Empirical treatment with ciprofloxacin has been shown to reduce the duration of diarrhea and other symptoms regardless of whether a pathogen was detected 5
• Gastrointestinal side effects may occur with antibiotic treatment, which can be exacerbated by the primary infection 2