What is Enteroinvasive Escherichia coli (E. coli)?

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Last updated: May 9, 2025View editorial policy

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From the Guidelines

Enteroinvasive Escherichia coli (EIEC) infections should be treated with antibiotics such as trimethoprim-sulfamethoxazole (TMP-SMZ) or fluoroquinolones, as outlined in the guidelines for immunocompetent patients 1. The treatment approach for EIEC infections is based on the severity of the illness and the patient's immune status.

  • For immunocompetent patients, the recommended treatment is TMP-SMZ, 160 and 800 mg, respectively, twice daily for 3 days, or fluoroquinolone, such as 300 mg ofloxacin, 400 mg norfloxacin, or 500 mg ciprofloxacin, twice daily for 3 days, as indicated in the guidelines 1.
  • The choice of antibiotic should be guided by local resistance patterns and the severity of the infection.
  • It is essential to note that the treatment of EIEC infections with antibiotics can help alleviate symptoms and reduce the risk of complications, but it is crucial to use antibiotics judiciously to minimize the development of antibiotic resistance.
  • In addition to antibiotic treatment, supportive care with fluid and electrolyte replacement is essential to manage symptoms and prevent dehydration.
  • Prevention measures, such as proper handwashing, consuming thoroughly cooked foods, drinking purified water, and careful food handling, are also crucial to prevent the spread of EIEC infections 1.

From the Research

Characteristics of Enteroinvasive E. coli

  • Enteroinvasive Escherichia coli (EIEC) is an intestinal pathogen that causes enteritis with a similar pathogenic mechanism to Shigella, leading to epithelial invasion of the large bowel, inflammation, and ulceration of the mucosa 2.
  • EIEC strains are atypical in their biochemical reactions, may ferment lactose late or not at all, are lysine decarboxylase negative, and non-motile 2.
  • Most EIEC strains express somatic antigens that are either strongly related or identical to Shigella antigens 2.

Epidemiology of Enteroinvasive E. coli

  • EIEC has been isolated with some regularity in South America, the Extreme Orient, and Eastern Europe 2.
  • In Spain, the incidence of enteroinvasive E. coli is extraordinarily low (0.2%), with the serogroup O124 being the most frequently isolated 2.
  • EIEC enteritis has been associated with sporadic cases in travelers, and occasional outbreaks have been reported related to ingestion of contaminated water or food and person-to-person transmission 2.
  • A study in northern coastal Ecuador found a high prevalence of EIEC, with 3.2 cases per 100 persons, making it the most frequently identified pathogenic E. coli 3.

Antibiotic Resistance and Treatment

  • While there is limited data on the antibiotic resistance of EIEC specifically, a study on invasive E. coli infections found that 9.18% of cases were resistant to extended-spectrum cephalosporins, 28.22% to fluoroquinolones, and 0.14% to carbapenems 4.
  • Another study on Enterococcus bacteraemia found that amoxicillin use was associated with a better outcome, highlighting the importance of appropriate antibiotic therapy 5.

Emerging Trends and Biofilm Formation

  • A recent study identified an emergent EIEC serotype O96:H19 that is capable of forming biofilms, which may contribute to its virulence and disease severity 6.
  • This biofilm-forming EIEC (BF-EIEC) has been recognized in Europe, Colombia, and Uruguay, and is associated with moderate-to-severe gastroenteritis in children under 5 years of age 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Epidemiology of Invasive Escherichia coli Infection and Antibiotic Resistance Status Among Patients Treated in US Hospitals: 2009-2016.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2021

Research

Antibiotic therapy for Enterococcus bacteraemia: warning for the antimicrobial stewardship team.

European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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