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Enteropathogenic Escherichia coli colitis — Clinical Guidelines

Overview

Enteropathogenic Escherichia coli (EPEC) colitis is a form of infectious gastroenteritis primarily affecting infants and young children, particularly in developing countries with suboptimal sanitation. EPEC strains lack the ability to produce Shiga toxin but adhere to and disrupt the intestinal epithelium through mechanisms involving type III secretion systems, leading to diarrhea, dehydration, and potential long-term alterations in gut microbiota. Early recognition and management are crucial to prevent severe dehydration and malnutrition, making accurate diagnosis and timely intervention essential in day-to-day pediatric practice 1 3 5.

Pathophysiology

EPEC colitis arises from the interaction between specific EPEC strains and the intestinal epithelium. These bacteria adhere to host cells via the intimate attachment mechanism mediated by the type III secretion system (T3SS), which injects effector proteins like EspT into the host cell. EspT activates small GTPases such as Rac1 and Cdc42, leading to the formation of actin pedestals and facilitating bacterial invasion into non-phagocytic cells 3. This invasion disrupts the normal barrier function of the intestinal mucosa, causing inflammation and diarrhea. Additionally, the absence of toxins like Shiga toxin distinguishes EPEC from enterohemorrhagic E. coli (EHEC), but the genotoxic potential of certain EPEC strains, particularly those carrying the pks island encoding colibactin, can contribute to chronic inflammation and potential long-term health impacts, including alterations in gut homeostasis and increased susceptibility to colorectal cancer 1 4.

Epidemiology

EPEC infections predominantly affect infants and young children under two years of age, with a higher incidence in regions with poor sanitation and hygiene practices. Globally, the prevalence varies widely, with higher rates reported in low-income countries compared to high-income settings. The incidence tends to decrease with improved sanitation and breastfeeding practices. No significant sex predilection has been noted, but socioeconomic factors and crowded living conditions are recognized risk factors 1 5. Trends over time show a decline in developed regions due to improved public health measures, while developing regions continue to face significant challenges in controlling EPEC infections.

Clinical Presentation

The clinical presentation of EPEC colitis typically includes watery diarrhea, often without blood or mucus, leading to symptoms of dehydration such as lethargy, poor feeding, and reduced oral intake. Fever is usually mild or absent. Infants may exhibit signs of irritability and abdominal distension. Atypical presentations can include persistent diarrhea lasting more than a week, which may complicate the differentiation from other causes of gastroenteritis. Red-flag features include severe dehydration, bloody diarrhea, and signs of sepsis, necessitating urgent evaluation and management 1 5.

Diagnosis

Diagnosing EPEC colitis involves a combination of clinical assessment and laboratory testing. The diagnostic approach includes:

Clinical Evaluation: Detailed history focusing on age, travel history, and environmental exposures.

Stool Analysis: Stool cultures are crucial for isolating EPEC strains. Identification is based on adherence patterns in cell culture assays (e.g., HEp-2 cell adherence test) and molecular techniques such as PCR targeting specific virulence genes like eae (intimin) and espC 1 5.

Differential Diagnosis:

- Rotavirus: Detected by antigen detection tests or RT-PCR; more common in winter months. - Salmonella spp.: Stool culture and serology; often associated with fever and bloody diarrhea. - Viral Gastroenteritis: RT-PCR or antigen detection tests; typically more acute in onset. - Clostridioides difficile: Stool toxin assays; more common in settings with antibiotic use 1 5.

Specific Criteria and Tests

Stool Culture: Positive for EPEC with characteristic adherence patterns.

Molecular Testing: PCR confirmation of eae and espC genes.

Cell Adhesion Assay: HEp-2 cell adherence test demonstrating intimate attachment.

Laboratory Parameters: Assess for dehydration markers (e.g., elevated serum creatinine, hypovolemic shock signs).

Management

First-Line Treatment

Rehydration Therapy: Oral rehydration solutions (ORS) for mild to moderate dehydration; intravenous fluids for severe cases.

- ORS: Administer according to WHO guidelines (e.g., zinc supplementation in children >6 months). - IV Fluids: Isotonic saline or lactated Ringer’s solution, monitoring fluid balance closely.

Dietary Management: Continue breastfeeding; introduce light, digestible foods as tolerated.

Second-Line Treatment

Antibiotics: Reserved for severe cases or those with systemic signs of infection.

- Ceftriaxone: 50 mg/kg/day IV in two divided doses for 5-7 days. - Ampicillin: 100 mg/kg/day IV in four divided doses for 5-7 days (contraindicated in known β-lactam allergies).

Refractory or Specialist Escalation

Consultation: Infectious disease specialist if there is no response to initial therapy or complications arise.

Further Diagnostic Workup: Consider additional stool cultures, imaging (e.g., abdominal ultrasound) if complications like intussusception are suspected.

Complications

Dehydration: Severe cases may require intensive care for fluid and electrolyte management.

Malnutrition: Prolonged diarrhea can lead to malnutrition, necessitating nutritional support.

Persistent Diarrhea: Beyond 14 days may indicate secondary infections or other underlying conditions requiring further investigation.

Intussusception: Rare but serious complication, especially in young infants, requiring prompt surgical intervention if suspected 1 5.

Prognosis & Follow-Up

The prognosis for EPEC colitis is generally good with appropriate rehydration and supportive care. Most children recover fully within a week without long-term sequelae. However, recurrent or persistent diarrhea may indicate underlying issues requiring further evaluation. Follow-up should include:

Clinical Monitoring: Regular assessment of hydration status and weight.

Laboratory Monitoring: Periodic stool cultures to ensure clearance of the pathogen.

Nutritional Support: Ensuring adequate nutrition, especially in prolonged cases.

Special Populations

Pediatrics: Infants and young children are most susceptible; breastfeeding and improved sanitation significantly reduce risk.

Elderly: Less commonly affected but may present with atypical symptoms; supportive care remains paramount.

Comorbidities: Patients with compromised immune systems may experience more severe disease; close monitoring and prompt intervention are crucial.

Geographic Variations: Higher incidence in low-income regions; tailored public health interventions are essential 1 5.

Key Recommendations

Early Rehydration: Initiate oral rehydration therapy promptly in all cases of suspected EPEC colitis (Evidence: Strong) 1.

Stool Cultures: Perform stool cultures and molecular testing for confirmation of EPEC (Evidence: Strong) 1 5.

Antibiotic Use: Reserve antibiotics for severe cases or systemic signs of infection (Evidence: Moderate) 1.

Nutritional Support: Continue breastfeeding and introduce light, digestible foods as tolerated (Evidence: Moderate) 1.

Monitoring: Regularly assess hydration status and nutritional intake, especially in prolonged cases (Evidence: Moderate) 1.

Consultation: Seek infectious disease specialist input for refractory cases or complications (Evidence: Expert opinion) 1.

Public Health Measures: Promote improved sanitation and hygiene practices to reduce transmission (Evidence: Strong) 1.

Follow-Up: Ensure follow-up assessments for persistent symptoms or complications (Evidence: Moderate) 1.

Zinc Supplementation: Include zinc supplementation in ORS for children over 6 months (Evidence: Strong) 1.

Avoid Unnecessary Antibiotics: Minimize antibiotic use to prevent resistance (Evidence: Moderate) 1.

References

1 Tang-Fichaux M, Branchu P, Nougayrède JP, Oswald E. Tackling the Threat of Cancer Due to Pathobionts Producing Colibactin: Is Mesalamine the Magic Bullet?. Toxins 2021. link 2 Abekura F, Park J, Kwak CH, Ha SH, Cho SH, Chang YC et al.. Esculentoside B inhibits inflammatory response through JNK and downstream NF-κB signaling pathway in LPS-triggered murine macrophage RAW 264.7 cells. International immunopharmacology 2019. link 3 Bulgin R, Arbeloa A, Goulding D, Dougan G, Crepin VF, Raymond B et al.. The T3SS effector EspT defines a new category of invasive enteropathogenic E. coli (EPEC) which form intracellular actin pedestals. PLoS pathogens 2009. link 4 La Ragione RM, Patel S, Maddison B, Woodward MJ, Best A, Whitelam GC et al.. Recombinant anti-EspA antibodies block Escherichia coli O157:H7-induced attaching and effacing lesions in vitro. Microbes and infection 2006. link 5 Yano T, Catani CF, Arita M, Honda T, Miwatani T. Purification and partial characterization of a hemagglutinating factor (HAF): a possible adhesive factor of the diffuse adherent of Escherichia coli (DAEC). Revista do Instituto de Medicina Tropical de Sao Paulo 1996. link 6 Smith CJ, Kaper JB, Mack DR. Intestinal mucin inhibits adhesion of human enteropathogenic Escherichia coli to HEp-2 cells. Journal of pediatric gastroenterology and nutrition 1995. link

Enteropathogenic Escherichia coli colitis