Treatment of Shiga Toxin-Producing Escherichia Coli (STEC) Infections
The primary treatment for STEC infections is supportive care with careful fluid management, while antimicrobial therapy should be avoided for STEC O157 and other STEC that produce Shiga toxin 2 due to increased risk of hemolytic uremic syndrome (HUS). 1
Supportive Care
Fluid Management
- Early and aggressive parenteral volume expansion is crucial in STEC infections to prevent complications, especially in patients at risk for HUS 1, 2
- Reduced osmolarity oral rehydration solution (ORS) is recommended as first-line therapy for mild to moderate dehydration 1
- For severe dehydration, shock, altered mental status, or failure of oral rehydration therapy, isotonic intravenous fluids such as lactated Ringer's or normal saline should be administered 1
- Early volume expansion (increasing body weight by approximately 10%) has been shown to reduce central nervous system involvement, need for renal replacement therapy, and hospitalization duration 2
Monitoring
- Close monitoring for development of HUS is essential, particularly in children under 5 years who are at highest risk 1
- Monitor for thrombocytopenia, hemolytic anemia, and renal failure, which characterize HUS 1, 3
- Watch for extrarenal complications including neurological manifestations (altered mental status, seizures), gastrointestinal complications, and cardiac involvement 3
Antimicrobial Therapy Considerations
Contraindications
- Antimicrobial therapy should be avoided in infections caused by STEC O157 and other STEC that produce Shiga toxin 2 1
- Multiple retrospective studies have shown higher rates of HUS in patients treated with antimicrobials 1
- In vitro data indicate that certain antimicrobial agents can increase Shiga toxin production 1
Special Populations
- For immunocompromised patients with severe illness and bloody diarrhea, empiric antibacterial treatment may be considered, but the risks of HUS development must be carefully weighed 1
- Asymptomatic contacts of people with STEC infection should not receive antimicrobial therapy 1
Adjunctive Therapies
Contraindicated Treatments
- Antimotility agents should not be used in suspected or documented STEC infections as they may increase the risk of HUS 1
Emerging Therapies
- For severe cases of STEC-HUS unresponsive to supportive care, eculizumab (a terminal complement inhibitor) has shown promise in case reports, though it is not yet standard of care 4, 5
- Research is ongoing into Shiga toxin-neutralizing monoclonal antibodies, though these remain investigational 5, 6
Prevention of Complications
- Prompt and accurate diagnosis is crucial for appropriate management and prevention of complications 1
- Early volume expansion may reduce thrombus formation and ischemic organ damage, improving both short and long-term outcomes 2
- For patients developing HUS, specialized care including possible dialysis and intensive supportive measures may be required 3, 5
Common Pitfalls to Avoid
- Administering antibiotics for STEC O157 infections, which may increase the risk of HUS 1
- Using antimotility agents, which can worsen outcomes 1
- Inadequate fluid resuscitation in the early stages of infection 2
- Failure to monitor for development of HUS, especially in high-risk populations such as children under 5 years 1