Treatment of Enteropathogenic E. coli (EPEC) Infection
For suspected EPEC infection in immunocompetent patients, treat with TMP-SMZ 160/800 mg twice daily for 3 days (if susceptible) or a fluoroquinolone such as ciprofloxacin 500 mg twice daily for 3 days. 1
Treatment Algorithm
First-Line Antibiotic Options
Immunocompetent patients should receive one of the following regimens 1:
- TMP-SMZ (trimethoprim-sulfamethoxazole): 160/800 mg twice daily for 3 days (if organism is susceptible)
- Fluoroquinolones (if TMP-SMZ resistance or allergy):
Immunocompromised patients should receive the same antibiotics but treatment should be extended to 7-10 days 1.
Important Clinical Considerations
Obtain stool cultures before initiating antibiotics to identify the organism and determine susceptibility patterns, as local resistance patterns should guide therapy 1, 2. However, treatment may be initiated empirically while awaiting culture results 2.
For empiric treatment of febrile dysenteric diarrhea when invasive bacterial enteropathogens are suspected (including EPEC), adults may receive azithromycin 1000 mg as a single dose 4.
Critical Distinction: Rule Out STEC
Do NOT treat if Shiga toxin-producing E. coli (STEC/enterohemorrhagic E. coli) is suspected, as antibiotics may increase the risk of hemolytic uremic syndrome (HUS) 1. STEC typically presents with low-grade or absent fever in patients with acute dysentery, unlike EPEC which causes fever 4. When STEC is suspected, stool should be tested for E. coli O157:H7 and Shiga toxin directly 1, 4.
Pathophysiology Context
EPEC causes attaching and effacing (A/E) lesions on intestinal epithelium, leading to destruction of microvilli, loss of glycocalyx, villous atrophy, and severe malabsorption 5, 6, 7. The organism adheres throughout the entire intestinal tract from jejunum to rectum, causing protracted diarrhea that can be severe, particularly in infants 6. In adults, EPEC can cause chronic diarrhea lasting weeks and may be associated with significant electrolyte abnormalities including hyponatremia 8.
Monitoring and Follow-up
Stool should be collected early in the illness (ideally before antibiotic administration) as bacteria become difficult to detect after 1 week of illness 1. For patients with persistent symptoms despite appropriate therapy, consider nutritional support with lactose-free formulas or protein hydrolysates, as secondary food intolerance may perpetuate diarrhea 5.