When are antibiotics appropriate for gastritis and food‑borne illness?

Antibiotics for Gastritis and Food Poisoning

Antibiotics are NOT routinely indicated for uncomplicated gastritis or most cases of food poisoning—the vast majority of foodborne illnesses are self-limited and require only supportive care with rehydration. 1, 2

When Antibiotics Are NOT Needed

Most foodborne bacterial gastroenteritis does not require antibiotic therapy. The decision to withhold antibiotics is based on:

• Self-limited nature: Most infections resolve spontaneously within 3-7 days without antimicrobial intervention 2
• Resistance concerns: Empiric antibiotic use drives antimicrobial resistance and should be avoided when not clinically indicated 3, 2
• Lack of mortality benefit: Uncomplicated gastroenteritis in immunocompetent patients does not benefit from antibiotics in terms of morbidity or mortality 1, 2

When Antibiotics ARE Indicated

Antibiotic therapy should be reserved for specific clinical scenarios where bacterial infection is severe, invasive, or occurs in high-risk patients. 1, 2

Clinical Indicators for Antibiotic Treatment:

• Severe systemic illness: High fever (>38.5°C), signs of sepsis, or hemodynamic instability 1, 2
• Bloody diarrhea with fever: Suggests invasive bacterial infection (Salmonella, Shigella, Campylobacter) 1, 2
• Immunocompromised patients: Including those on chemotherapy, post-transplant, or with HIV/AIDS 3, 2
• Suspected Salmonella bacteremia: Particularly high risk in elderly, infants, or those with vascular grafts 3, 4
• Prolonged symptoms: Diarrhea persisting beyond 7-10 days warrants investigation and possible treatment 1, 2

Empiric Antibiotic Selection (When Indicated):

For suspected invasive bacterial gastroenteritis with systemic features:

• First-line: Ciprofloxacin 500mg twice daily OR Levofloxacin 500mg once daily for 3-5 days 3, 1
• Alternative (if fluoroquinolone resistance suspected): Ceftriaxone 1-2g IV daily 3
• For Salmonella bacteremia: Ceftriaxone PLUS ciprofloxacin initially to prevent treatment failure before susceptibility results, then de-escalate to monotherapy 3

Common pitfall: Avoid fluoroquinolones in areas with high resistance rates or if recent quinolone exposure 3

Gastritis-Specific Considerations

H. pylori-Associated Gastritis:

All patients with peptic ulcer disease or gastritis should be tested for H. pylori, and if positive, eradication therapy is mandatory to prevent recurrent disease and reduce mortality from complications. 3

Standard triple therapy (14 days) in areas with low clarithromycin resistance (<15%): 3

• PPI (standard dose twice daily)
• Clarithromycin 500mg twice daily
• Amoxicillin 1000mg twice daily

Sequential therapy (10 days) if high clarithromycin resistance: 3

• Days 1-5: PPI + Amoxicillin 1000mg twice daily
• Days 6-10: PPI + Clarithromycin 500mg twice daily + Metronidazole 500mg twice daily

Second-line therapy (if first-line fails): 3

• PPI (standard dose twice daily)
• Levofloxacin 500mg once daily
• Amoxicillin 1000mg twice daily for 10 days

Critical point: Start H. pylori eradication therapy 72-96 hours after IV PPI administration in bleeding peptic ulcer patients 3

Non-H. pylori Gastritis:

Antibiotics are NOT indicated for non-infectious gastritis (NSAID-induced, stress-related, autoimmune) unless there is evidence of perforation with peritonitis. 3

Complicated Gastritis with Perforation

If gastric perforation occurs, this becomes a surgical emergency requiring source control PLUS antibiotics: 3

For immunocompetent, non-critically ill patients with adequate source control:

• Amoxicillin/Clavulanate 2g/0.2g every 8 hours for 4 days 3
• Beta-lactam allergy: Eravacycline 1mg/kg every 12 hours OR Tigecycline 100mg loading dose, then 50mg every 12 hours 3

For critically ill or immunocompromised patients:

• Piperacillin/tazobactam 4g/0.5g every 6 hours (or continuous infusion) for up to 7 days 3
• If septic shock: Meropenem 1g every 6 hours by extended infusion 3

Key Clinical Pitfalls to Avoid

• Never use antibiotics empirically for simple gastroenteritis without clear indications—this increases resistance without improving outcomes 3, 2
• Do not continue antibiotics beyond 5-7 days without diagnostic investigation for persistent symptoms, as this suggests treatment failure or alternative diagnosis 3
• Avoid treating non-typhoidal Salmonella gastroenteritis with antibiotics in immunocompetent patients—this may prolong carrier state without clinical benefit 3, 2
• Never assume all gastritis requires antibiotics—only H. pylori-positive cases or complicated perforations need antimicrobial therapy 3
• Source control is mandatory in perforated gastritis—antibiotics alone without surgical intervention result in therapeutic failure and increased mortality 3