- Enterotoxigenic E.coli contributes to undifferentiated neonatal calf diarrhoea, a mixed viral enteritis in calves.
- Colibacillosis.
- Histiocytic ulcerative colitis in the dog and cat.
- Causes secretory diarrhoea
- Causes peritonitis in dogs and peritonitis in pigs
- In osteomyelitis
- In neonatal polyarthritis of calves
- In arthritis of horses
Eschericia coli (E. coli) overview
- Member of Enterobacteriacae family of Gram-negative bacilli
- Facultative anaerobe
- One of predominant bacterial species in colonic flora
- Abundant in the environment
- Found in many non-specific, endogenous infections, eg. wound infections and upper respiratory tract infections and septicaemia
- Also and enteropathogen
E. coli characteristics
- Oxidase negative (do not possess cytochrome C oxidase)
- Grow on MacConkey agar (in presence of bile salts)
- Reduce nitrates to nitrits and ferment glucose to produce acid and gas
- Possess a lipolysaccharide (O) antigen, a flagellate (H) antigen, polysaccharide capsule (K) antigens and fimbrial (F) antigens
- Epidemiological typing of E. coli uses antigen combinations, eg. O125:K12:H42
Extra-intestinal infection
- Soft tissue infections in adult animals
- Most common organism infecting urinary tract
- Causes pyometra in the dog and cat and pyelonephritis
- Acute mastitis in lactating animals
- Pathogenesis:
- Produces an alpha-haemolysin which may be cytotoxic
- Iron aquisition system
- K antigens prevent phagocytosis or mimic host antigens and resist complement
- Fimbriae permit adhesion to mucosal surfaces
- May enter blood to cause septicaemia
- Clinical infections:
- Avian colibacillosis:
- Septicaemia in newly-hatched chickens
- Infection enters via faecal contamination of the egg surface or via the ovary of the hen
- Infection enters via the respiratory tract
- A bacteraemia develops
- Acute colisepticaemia, subacute fibrinopurulent serositis or chronic granulomatous disease of the viscera
- Occurs in older birds via inhalation of E. coli in dust; respiratory infection spreads to the blood to cause acute colisepticaemia
- Airsacculitis, pericarditis and perihepatitis during acute phase
- Often secondary to virus or mycoplamsa infection or environmental stress
- Colisepticaemia:
- Systemic disease in young calves, piglets, foals, lambs
- Penetration of intestinal mucosa and entrance into the blood
- Invasive strains survive the host defences
- Virulence related to adhesive properties, complement resistance and ability for iron aquisition
- Ammonia, dust, viral infections and temperature changes enhance likelihood of disease
- Avian colibacillosis: