Treatment of Salmonella-Positive Patients
For immunocompetent adults and children over 3 months with uncomplicated Salmonella gastroenteritis, do NOT give antibiotics—provide only oral rehydration and supportive care. 1, 2, 3
When Antibiotics Are Required
Treatment is mandatory in these specific populations:
- Infants <3 months of age: Bacteremia risk reaches 45% in neonates and 11% in older infants, with high risk of meningitis and osteomyelitis 2, 3, 4
- All immunocompromised patients: Including HIV/AIDS, transplant recipients, chronic immunosuppression, or malignancy 1, 3, 5
- Documented bacteremia or sepsis: Any patient with positive blood cultures 3, 5
- Severe invasive disease: Patients requiring hospitalization with fever ≥38.5°C, signs of sepsis, or suspected enteric fever 1, 3
- Pregnant women: Risk of placental infection and pregnancy loss 3, 5
First-Line Antibiotic Regimens
For Adults (Immunocompetent)
- Ciprofloxacin 500 mg PO twice daily for 7-14 days 3, 5
- Alternative: Azithromycin based on local resistance patterns 1
For Adults (Immunocompromised/HIV)
- Ceftriaxone 2 g IV once daily PLUS ciprofloxacin 500 mg PO twice daily until susceptibilities available 3, 5
- Duration: 2-6 weeks for advanced HIV (CD4+ <200 cells/μL) 3, 5
- Long-term suppression: Consider ciprofloxacin 500 mg twice daily for ≥2 months after initial treatment to prevent recurrence 3
For Infants <3 Months
- First-line options: TMP-SMX, ampicillin, cefotaxime, or ceftriaxone based on local susceptibility 2, 3
- Avoid fluoroquinolones due to cartilage toxicity risk 2, 5
- Duration: 7-14 days minimum 2
For Children >3 Months (If Treatment Required)
- TMP-SMX, ceftriaxone, or cefotaxime as first-line 2, 3
- Azithromycin as alternative based on travel history and local resistance 1, 2
- Never use fluoroquinolones except in life-threatening situations with no alternatives 2, 5
For Pregnant Women
Critical Supportive Care (All Patients)
- Reduced osmolarity ORS as first-line for mild-moderate dehydration until clinical correction, then continue to replace ongoing losses 1, 2
- Resume age-appropriate diet immediately after rehydration—do not delay feeding 2
- Continue breastfeeding throughout illness if applicable 2
Medications to Absolutely Avoid
- Antimotility agents (loperamide): Strong contraindication in all children <18 years—can precipitate toxic megacolon and worsen invasive disease 1, 2
- Antibiotics in uncomplicated cases: Prolong fecal shedding (mean 41.3 days with ampicillin vs 20.9 days with placebo), increase relapse rates (53% vs 0%), and cause more adverse effects without shortening illness duration 6, 7
Why Antibiotics Harm in Uncomplicated Cases
The evidence is unequivocal: In immunocompetent patients with mild gastroenteritis, antibiotics provide no clinical benefit (length of illness -0.07 days, 95% CI -0.55 to 0.40) but significantly increase adverse effects (OR 1.67,95% CI 1.05-2.67) and bacteriologic relapse 6. Ampicillin/amoxicillin studies show 53% relapse rates versus 0% with placebo, with no reduction in diarrhea duration 7. This harm occurs even when organisms remain susceptible in vitro 7.
Treatment Failure Definition
Lack of clinical improvement AND persistent positive blood cultures after completing therapy 3. When this occurs:
- Evaluate for malabsorption of oral antibiotics 3
- Search for undrained abscess or sequestered infection 3
- Consider co-infection (C. difficile) 3
- Reassess antimicrobial susceptibility 1
Special Considerations
- Expect persistent fever for 5-7 days despite appropriate antibiotic therapy 3
- Follow-up stool cultures NOT required if complete clinical response demonstrated 3
- Screen household contacts for asymptomatic carriage in immunocompromised patients to prevent reinfection 2, 3
- Avoid STEC treatment: If Shiga toxin-producing E. coli cannot be excluded, withhold antibiotics until ruled out 1