Enteropathogenic E. coli Infection

Enteropathogenic Escherichia coli (EPEC) adheres to enterocytes via bundle forming pili and intimin, producing attaching and effacing lesions with loss of microvilli.

• It mainly affects infants under 2 years in low income countries, with high mortality in the 1950s to 1970s and still significant in Africa.
• Spread is faecal-oral, via contaminated feeds, bottles, water and hospital outbreaks.
• Typical EPEC (with bundle forming pili) is more virulent than atypical EPEC.

Watery, often mucoid diarrhoea with vomiting, low grade fever and dehydration in infants.

• Diarrhoea can persist beyond 14 days with malabsorption, weight loss and failure to thrive.
• Differential diagnosis: rotavirus, enterotoxigenic E coli, cholera, Shigella, Cryptosporidium, cow's milk protein intolerance, lactose intolerance, HIV enteropathy.
• Complications: dehydration, electrolyte disturbance, persistent diarrhoea, malnutrition, secondary lactose intolerance, nosocomial outbreaks in neonatal units.

Clinical assessment of hydration and nutritional status (weight, mid upper arm circumference).

• Stool PCR for eae gene with absence of Shiga toxin genes; serotyping is of historical use only.
• Electrolytes, urea and glucose in dehydrated infants; HIV test for persistent diarrhoea.
• Stool microscopy and culture to exclude other pathogens.

Supportive

• Low osmolarity oral rehydration solution, 50 to 100 mL/kg over 4 hours in moderate dehydration; Ringer lactate 30 mL/kg over 30 minutes then 70 mL/kg over 2.5 hours (infants under 12 months: 30 mL/kg over 1 hour then 70 mL/kg over 5 hours) for severe.
• Continue breastfeeding and age appropriate feeding; lactose free formula only if persistent diarrhoea with lactose intolerance.
• Zinc 20 mg daily for 10 to 14 days (10 mg under 6 months).

Pharmacological

• Antibiotics for severe or persistent disease and in neonatal outbreaks: azithromycin 10 mg/kg once daily for 3 days (day 1 up to 20 mg/kg if needed), or cotrimoxazole 4 mg/kg trimethoprim twice daily for 5 days if the isolate is susceptible.
• Gentamicin 5 to 7.5 mg/kg daily IV for 5 to 7 days if systemic features in neonates (adjust for age).
• Vitamin A 100,000 IU (6 to 11 months) or 200,000 IU (12 months and above) once for persistent diarrhoea in deficiency settings.

Special groups: neonates (barrier nursing, cohort care), HIV exposed children (antiretroviral therapy, cotrimoxazole prophylaxis), malnourished children (inpatient care with therapeutic milk feeds providing 75 kcal/100 mL initially, then 100 kcal/100 mL).

Red flags: severe dehydration, lethargy, bloody stool, persistent diarrhoea beyond 14 days, severe acute malnutrition.

Follow-up: weight check at 1 week; catch-up feeding; reinforce handwashing, safe water, exclusive breastfeeding to 6 months.