What antibiotic treatment is recommended for a patient with vomiting, suspected to be caused by a bacterial infection, such as food poisoning or bacterial gastroenteritis?

Antibiotic Treatment for Vomiting

Antibiotics are generally NOT recommended for vomiting caused by gastroenteritis, as 70% of cases are viral and antibiotics provide no benefit. 1, 2

When Antibiotics Are NOT Indicated

• Do not give empiric antibiotics for typical watery diarrhea with vomiting, as the majority of acute gastroenteritis is viral and self-limiting 1, 2
• Rehydration with oral rehydration solution (ORS) is the cornerstone of treatment, not antibiotics 1, 3
• Antibiotic therapy for uncomplicated gastroenteritis does not improve outcomes and may cause harm in certain infections 4

When to Consider Antibiotics

Empiric antimicrobial therapy should only be given for specific high-risk scenarios: 1, 2

High-Risk Populations Requiring Treatment:

• Infants <3 months of age with suspected bacterial etiology 1
• Immunocompromised patients with severe illness and bloody diarrhea 1
• Pregnant women with Salmonella gastroenteritis (to prevent extraintestinal spread) 1
• Patients with fever, abdominal pain, bloody diarrhea, and bacillary dysentery presumptively due to Shigella 1, 2

Empiric Antibiotic Choices When Indicated:

For Adults: 1, 2

• Ciprofloxacin (fluoroquinolone) OR
• Azithromycin (preferred if fluoroquinolone resistance suspected)

For Children: 1, 2

• Azithromycin (first-line) OR
• Third-generation cephalosporin (ceftriaxone or cefotaxime)

Pathogen-Specific Recommendations:

According to the Infectious Diseases Society of America: 5

• Campylobacter: Azithromycin (first choice) or ciprofloxacin
• Shigella: Azithromycin, ciprofloxacin, or ceftriaxone (avoid fluoroquinolones if MIC ≥0.12 μg/mL)
• Salmonella (nontyphoidal): Usually NOT indicated for uncomplicated infection 5
• Salmonella typhi/paratyphi: Ceftriaxone or ciprofloxacin 5

Critical Pitfalls to Avoid

• NEVER use antibiotics for STEC O157 or other Shiga toxin-producing E. coli, as this increases the risk of hemolytic uremic syndrome 1
• Avoid fluoroquinolones if local E. coli resistance is >10% (quinolone-resistant E. coli are common in many communities) 5
• Do not use loperamide in children <18 years - deaths have been reported in 0.54% of children given loperamide 3

Supportive Management Priority

The primary treatment for vomiting from gastroenteritis is rehydration, not antibiotics: 1, 2

• Oral rehydration solution (ORS) 50-100 mL/kg over 3-4 hours for mild-moderate dehydration 1
• Ondansetron may be given to children >4 years and adults to facilitate oral rehydration 2, 3
• Resume age-appropriate diet immediately during or after rehydration 1, 2
• Continue breastfeeding throughout illness in infants 1

When to Reassess

If clinical symptoms worsen despite appropriate supportive care, consider: 5

• Stool culture and susceptibility testing
• Evaluation for C. difficile if healthcare exposure or recent antibiotics
• CT or ultrasound imaging if persistent symptoms after 5-7 days suggest complicated infection 5