Management of Bacterial Gastroenteritis
The primary treatment for bacterial gastroenteritis is oral rehydration therapy with reduced osmolarity oral rehydration solution, while antimicrobial therapy should be reserved for specific indications and pathogens. 1
Rehydration Therapy
- Reduced osmolarity oral rehydration solution (ORS) is the first-line therapy for mild to moderate dehydration in both children and adults with bacterial gastroenteritis 1
- For patients with severe dehydration, shock, altered mental status, or ileus, isotonic intravenous fluids (lactated Ringer's or normal saline) should be administered until clinical improvement occurs 1
- Nasogastric administration of ORS may be considered for patients who cannot tolerate oral intake but have moderate dehydration 1
- Once rehydrated, maintenance fluids should be provided and ongoing stool losses replaced with ORS until diarrhea resolves 1
- Age-appropriate diet should be resumed during or immediately after rehydration is completed 1
Antimicrobial Therapy
General Principles
- Empiric antimicrobial therapy is generally not recommended for most cases of bacterial gastroenteritis 1
- Antimicrobial therapy should be considered in specific situations:
Specific Antimicrobial Regimens Based on Pathogen
Non-critically ill patients with community-acquired infections:
- Amoxicillin/clavulanate 1.2-2.2 g 6-hourly, OR
- Ceftriaxone 2 g 24-hourly + Metronidazole 500 mg 6-hourly, OR
- Cefotaxime 2g 8-hourly + Metronidazole 500 mg 6-hourly 2
For specific pathogens:
- Salmonella: Ciprofloxacin 400 mg bid IV or 500 mg bid PO; alternatives include levofloxacin 500 mg daily PO, amoxicillin 500 mg tid PO, or TMP-SMZ 160/180 mg bid PO/IV 2
- Shigella: Fluoroquinolone (e.g., ciprofloxacin 400 mg bid IV or 500 mg bid PO) or azithromycin 500 mg daily IV/PO 2
- Campylobacter: Azithromycin 500 mg daily IV/PO; alternative: fluoroquinolone (though 19% resistance rate noted) 2
- Yersinia: Fluoroquinolone (e.g., ciprofloxacin 400 mg bid IV or 500 mg bid PO); alternatives: TMP-SMZ 160/180 mg bid PO/IV or doxycycline 100 mg bid IV/PO 2
Duration of Therapy
- For uncomplicated cases with adequate source control, a short course of antibiotic therapy (3-5 days) is recommended 2
- For acute stomach and proximal jejunum perforations with source control within 24 hours, prophylactic anti-infective therapy for 24 hours is adequate 2
- Patients with ongoing signs of peritonitis or systemic illness beyond 5-7 days of antibiotic treatment should warrant diagnostic investigation 2
Supportive Care
- Antimotility drugs (e.g., loperamide) should not be given to children under 18 years with acute diarrhea 1
- Loperamide may be given to immunocompetent adults with acute watery diarrhea, but should be avoided in cases of inflammatory diarrhea or diarrhea with fever 1
- Antiemetics (e.g., ondansetron) may be given to facilitate oral rehydration in children over 4 years and adolescents with vomiting 1
- Probiotic preparations may be offered to reduce symptom severity and duration in immunocompetent patients 1
Monitoring and Follow-up
- Continue monitoring hydration status until symptoms resolve 1
- Antimicrobial therapy should be modified or discontinued when a specific pathogen is identified from diagnostic tests 1
- For persistent symptoms, reassessment of fluid and electrolyte balance, nutritional status, and antimicrobial therapy is recommended 1
Common Pitfalls to Avoid
- Avoid antimotility agents in children under 18 years and in patients with bloody diarrhea or fever due to risk of complications 1
- Avoid antibiotics for STEC O157 infections as they may increase the risk of hemolytic uremic syndrome 1
- Do not delay rehydration while waiting for diagnostic test results 1
- Recognize that most patients with bacterial gastroenteritis do not present with high fever or bloody diarrhea, but generally have quite severe diarrhea 3
- Be aware that stool cultures do not change management for most patients (88.5% in one study) 3