Escherichia coli

Please note: This is for information only.

Refer to local guidelines for treatment recommendations


  • A Gram-negative bacillus - the principal member of the enterobacteria family (Coliforms).
  • A common commensal in the gastro-intestinal tract.
  • The most common organism encountered in urinary tract infections.
  • Some biotypes of E coli are also enteric pathogens, causing diarrhoea. In particular, E coli O157 which causes haemorrhagic colitis and haemolytic uraemic syndrome. Infection control precautions are required for these strains.

Main clinical infections:

  • Urinary tract infections (principal cause).
  • Intra-abdominal infections e.g. appendicitis, perforations, peritonitis.
  • Ventilator-associated pneumonia. (Other chest infections are very rare.)

Usually sensitive to:

  • Trimethoprim
  • Cephalosporins
  • Quinolones (Ciprofloxacin, Levofloxacin)
  • Aminoglycosides (Amikacin, Gentamicin, Tobramycin)

Usually resistant to:

  • Amoxicillin : resistance is common (50-60%).
  • Resistance against trimethoprim and quinolones is also on the increase.