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→Pathogenesis
===''Eschericia coli'' (''E. coli'') overview===
===''Eschericia coli'' (''E. coli'') overview===
[[File:Ecoli.jpg|200px|right]]
*Member of ''Enterobacteriacae'' family of Gram-negative bacilli
*Member of ''Enterobacteriacae'' family of Gram-negative bacilli
*'''Facultative anaerobe'''
*'''Facultative anaerobe'''
*Capsular polysaccharides produced by some strains prevent phagocytosis and interfere with complement
*Capsular polysaccharides produced by some strains prevent phagocytosis and interfere with complement
*Endotoxin is a lipolysaccharide component of the cell wall of Gram-negative bacteria, composed of lipid A, a core polysaccharide and various side chains
*Endotoxin is a lipolysaccharide component of the cell wall of Gram-negative bacteria, composed of lipid A, a core polysaccharide and various side chains
*'''Endotoxin''' is realeased when bacteria die, and causes endothelial damage leading to [[Thrombosis - Pathology#Disseminated Intravascular Coagulation|'''disseminated intravascular coagulation''']] and e'''ndotoxic shock'''; it is also a '''pyrogen'''
*'''Endotoxin''' is realeased when bacteria die, and causes endothelial damage leading to [[Disseminated Intravascular Coagulation|'''disseminated intravascular coagulation''']] and '''endotoxic shock'''; it is also a '''pyrogen'''
*Enterotoxins, verotoxins and cytotoxic necrotising factors produced by many pathogenic ''E. coli''; these produce cell damage at their site of action
*Enterotoxins, verotoxins and cytotoxic necrotising factors produced by many pathogenic ''E. coli''; these produce cell damage at their site of action
*'''Alpha-haemolysin''' may increase iron availability for invading organisms
*'''Alpha-haemolysin''' may increase iron availability for invading organisms
*'''Siderophores''' are made by certain pathogenic strains, and are responsible for iron aquisition; they include aerobactin and enterobactin
*'''Siderophores''' are made by certain pathogenic strains, and are responsible for iron aquisition; they include aerobactin and enterobactin
==Extra-intestinal infection==
==Extra-intestinal infection==
***Most common organism infecting urinary tract
***Most common organism infecting urinary tract
***Ascending infections of urinary tract
***Ascending infections of urinary tract
***Causes pyometra in the dog and cat and [[Kidney Tubulointerstitial Disease - Pathology#Pyelonephritis|pyelonephritis]]
***Causes pyometra in the dog and cat and [[Pyelonephritis|pyelonephritis]]
***Cystitis in the bitch
***Cystitis in the bitch
***Prostatitis in dogs via opportunistic infection
***Prostatitis in dogs via opportunistic infection
***Morbidity and mortality high
***Morbidity and mortality high
** [[Inflammatory Bowel Disease#Histiocytic Ulcerative Colitis|Histiocytic ulcerative colitis]] in the dog and cat.
** [[Inflammatory Bowel Disease#Histiocytic Ulcerative Colitis|Histiocytic ulcerative colitis]] in the dog and cat.
** Causes [[Peritonitis - Cats and Dogs|peritonitis in dogs]] and [[Peritonitis - Pathology#In pigs|peritonitis in pigs]]
** Causes [[Peritonitis - Cats and Dogs|peritonitis in dogs]] and [[Peritonitis#In pigs|peritonitis in pigs]]
**Found in [[Bones Inflammatory - Pathology#Osteomyelitis|osteomyelitis]]
**Found in [[Osteomyelitis|osteomyelitis]]
**Associated with neonatal [[Joints Inflammatory - Pathology#In Cattle|polyarthritis of calves]]
**Associated with neonatal [[Infectious Arthritis#In Cattle|polyarthritis of calves]]
**In [[Bacterial skin infections - Pathology#Deep pyoderma|deep pyoderma]]
**In [[Deep Pyoderma|deep pyoderma]]
**Found in [[Joints Inflammatory - Pathology#In Horses|arthritis of horses]]
**Found in [[Infectious Arthritis#In Horses|arthritis of horses]]
==Intestinal infection==
==Intestinal infection==
*''E. coli'' is part of the flora of the large intestine, but is not usually found in the small intestine
*''E. coli'' is part of the flora of the large intestine, but is not usually found in the small intestine
*Some strains possess fimbrae which attach the bacteria to the small intestinal epithelium of particular animal species
*Some strains possess fimbrae which attach the bacteria to the small intestinal epithelium of particular animal species
*''E. coli'' may cause diarrhoea via attaching and effacing lesions, where bacteria adhere intimately to the enterocyte, and cause localised effacement of the brush border microvilli; the epithelial erosion causes [[Haemorrhage - Pathology#Dysentery|dysentery]]
*''E. coli'' may cause diarrhoea via attaching and effacing lesions, where bacteria adhere intimately to the enterocyte, and cause localised effacement of the brush border microvilli; the epithelial erosion causes [[Haemorrhage#Dysentery|dysentery]]
**Strains do not product LT or ST and are not enteroinvasive
**Strains do not product LT or ST and are not enteroinvasive
**Attaching and effacing lesions, unrelated to toxin production
**Attaching and effacing lesions, unrelated to toxin production
**[[Thrombosis - Pathology#Disseminated Intravascular Coagulation|Disseminated intravascular coagulation]] and thrombus formation
**[[Disseminated Intravascular Coagulation|Disseminated intravascular coagulation]] and thrombus formation
**''E. coli'' O157:H7 causes haemorrhagic collitis-haemolytic uraemic syndrome in humans
**''E. coli'' O157:H7 causes haemorrhagic collitis-haemolytic uraemic syndrome in humans
**Important virulence factors include toxin and fimbriae
**Important virulence factors include toxin and fimbriae
==in cattle==
*Neonatal polyarthritis:
**[[Escherichia coli|'''''Coliforms''''']]
***Localises in joints and meninges in severe non-fatal neonatal colibacillosis
***May remain as chronic arthritis in larger joints
[[Category:Enterobacteriaceae]]
[[Category:Enterobacteriaceae]]
[[Category:To_Do_-_Bacteria]]
[[Category:To_Do_-_Bacteria]]