Enterobacter: Genus-Escherichia
13 August 2020 14:11
The Enterobacteriaceae -Genus: Escherichia
The Escherichia coli was first isolated in 1919, by Theodor Escherich. E. coli is one of the five species
of the genera Escherichia: E.albertii, E.coli, E.fergusonii, E.hermannii, E.vulneris. All these species are
capable of causing disease in human.
E. coli colonises mammalian GI tract a few hours after birth and maintains regular presence over
lifetime. There are more than 700 different serotypes (antigens), O, H, K which are mostly harmless.
Pathogenic Escherichia strains are assigned to 'pathotypes' based on the type of disease they cause
and the virulence factors they harbour.
E.coli pathotypes associated with disease
Intestinal Infections (inside the intestine):
• Enteroaggregative E.coli (EAggEC)
• Enterotoxigenic E.coli (ETEC)
• Enteroinvasive E.coli (EIEC)
Attaching and effacing E.coli:
• Shiga toxin-producing E.coli (STEC) or Enterohaemorrhagic E.coli (EHEC)
• Enteropathogenic E.coli (EPEC)
Extra-intestinal infections (outside the intestine):
• Septicaemia E.coli (SEPEC)
• Meningitis-associated E.coli (MNEC)
• Uropathogenic E.coli (UPEC)
Serotype: serotype is the term used to refer to a group of organisms within a species that have the
same type and number of surface antigens.
These pathotypes causes these following diseases in mammals:
- Gastrointestinal disease (caused by EIEC, STEC/ EHEC, EAggEC, ETEC, EPEC)
- Urinary tract infections (caused by UPEC)
- Meningitis (caused by MNEC)
Urinary tract Infections (UTIs)
• 50% of women get UTI in their lifetime
• 75% of UTIs are caused by Uropathogenic E.coli (UPEC)
• UTI infection: 14x more common in females (shorter urethra)
• In the pre-antibiotic era, 15% of UTI cases were fatal
Types of UTI include:
○ Asymptomatic bacteriuria (1% normally, 20% elderly)
○ Cystitis (bladder infection)
○ Pyelonephritis (upper ureter infection, kidney infection)
Mechanism of UPEC infection
Gastrointestinal of healthy individuals is colonised by UPEC. Normally, UPEC are found in individuals
intestine. Periurethral contamination with UPEC can occur after a bowel movement.
1) Contamination of the periurethral area with a uropathogen from the gut.
2) Colonisation of the urethra and migration to the bladder.
3) Colonisation and invasion of the bladder, mediated by pili and adhesins. Inflammatory
response in the bladder and fibrinogen accumulation in the urinary catheter.
4) Neutrophil infiltration (damage)
5) Bacterial multiplication and immune system subversion (failure)
6) Biofilm formation
7) Epithelial damage by bacterial toxins and proteases.
E-Escherichia Page 1
13 August 2020 14:11
The Enterobacteriaceae -Genus: Escherichia
The Escherichia coli was first isolated in 1919, by Theodor Escherich. E. coli is one of the five species
of the genera Escherichia: E.albertii, E.coli, E.fergusonii, E.hermannii, E.vulneris. All these species are
capable of causing disease in human.
E. coli colonises mammalian GI tract a few hours after birth and maintains regular presence over
lifetime. There are more than 700 different serotypes (antigens), O, H, K which are mostly harmless.
Pathogenic Escherichia strains are assigned to 'pathotypes' based on the type of disease they cause
and the virulence factors they harbour.
E.coli pathotypes associated with disease
Intestinal Infections (inside the intestine):
• Enteroaggregative E.coli (EAggEC)
• Enterotoxigenic E.coli (ETEC)
• Enteroinvasive E.coli (EIEC)
Attaching and effacing E.coli:
• Shiga toxin-producing E.coli (STEC) or Enterohaemorrhagic E.coli (EHEC)
• Enteropathogenic E.coli (EPEC)
Extra-intestinal infections (outside the intestine):
• Septicaemia E.coli (SEPEC)
• Meningitis-associated E.coli (MNEC)
• Uropathogenic E.coli (UPEC)
Serotype: serotype is the term used to refer to a group of organisms within a species that have the
same type and number of surface antigens.
These pathotypes causes these following diseases in mammals:
- Gastrointestinal disease (caused by EIEC, STEC/ EHEC, EAggEC, ETEC, EPEC)
- Urinary tract infections (caused by UPEC)
- Meningitis (caused by MNEC)
Urinary tract Infections (UTIs)
• 50% of women get UTI in their lifetime
• 75% of UTIs are caused by Uropathogenic E.coli (UPEC)
• UTI infection: 14x more common in females (shorter urethra)
• In the pre-antibiotic era, 15% of UTI cases were fatal
Types of UTI include:
○ Asymptomatic bacteriuria (1% normally, 20% elderly)
○ Cystitis (bladder infection)
○ Pyelonephritis (upper ureter infection, kidney infection)
Mechanism of UPEC infection
Gastrointestinal of healthy individuals is colonised by UPEC. Normally, UPEC are found in individuals
intestine. Periurethral contamination with UPEC can occur after a bowel movement.
1) Contamination of the periurethral area with a uropathogen from the gut.
2) Colonisation of the urethra and migration to the bladder.
3) Colonisation and invasion of the bladder, mediated by pili and adhesins. Inflammatory
response in the bladder and fibrinogen accumulation in the urinary catheter.
4) Neutrophil infiltration (damage)
5) Bacterial multiplication and immune system subversion (failure)
6) Biofilm formation
7) Epithelial damage by bacterial toxins and proteases.
E-Escherichia Page 1
