Escherichia coli (diarrhoea)

Various strains of E. coli may cause diarrhoea by differing mechanisms.

Escherichia coli (E. coli) are gram negative, rod-shaped bacteria commonly found in the intestines of humans and animals making up part of the normal gut flora. Most are harmless;
however, certain types of E. coli are harmful to humans.

Traditionally, the specific strain was identified by serotype - 'O' somatic antigen - but increasingly, diagnosis is based on the direct demonstration of toxins - either their effect on cell cultures or immunologically - or by detection of the genes coding for them.

• E. coli causing gastroenteritis may be classified as
  • Enterohemorrhagic Escherichia coli (STEC, EHEC)
    • the enterohaemorrhagic E. coli (EHEC) are now generally referred to as Shiga toxinproducing E. coli (STEC). They are capable of producing the toxins Shiga toxin 1 (stx1) and Shiga toxin 2 (stx2) (named due to their similarity to the toxin produced by Shigella dysenteriae type 1).
    • STEC replaces the previous terminology ‘verocytotoxin-producing E. coli (VTEC)’.
    • Shiga toxin can be produced by both O157 and non-O157 serotypes. All O157 types (stx +ve and –ve) and non-O157 STEC (i.e. stx +ve) infections require urgent Public Health action
      
      
  • Enterotoxigenic (ETEC)
    
    
  • Enteropathogenic (EPEC)
    
    
  • Enteroinvasive (EIEC)
    
    
  • Enteroaggregative (EAEC, EAggEC)
    
    
  • Diffuse-adherent (DAEC) or Cytolethal distending toxin producing (CDT producing)

Treatment is usually supportive. Adequate fluid intake must be ensured. Codeine phosphate or loperamide may be given for symptom control but must never be used in children. Seek expert advice regarding use of antibiotics for this condition.

Reference:

• PHE (2019). Recommendations for the Public Health Management of Gastrointestinal Infections