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− | <big><center>[[Enterobacteriaceae|'''BACK TO ENTEROBACTERIACEAE''']]</center></big>
| + | {{review}} |
− | <big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big>
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− | <big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big>
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| ===''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''' |
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| *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 '''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 |
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| ==Extra-intestinal infection== | | ==Extra-intestinal infection== |
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| ***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#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 |
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| ***Death within 24-48 hours during peracute disease | | ***Death within 24-48 hours during peracute disease |
| ***Animals depressed with sunken eyes | | ***Animals depressed with sunken eyes |
− | **[[Intestines - Catarrhal Enteritis#Colibacillosis|'''Colibacillosis''']]: | + | **[[Colibacillosis|'''Colibacillosis''']]: |
| ***Avian: | | ***Avian: |
| ****Septicaemia in newly-hatched chickens | | ****Septicaemia in newly-hatched chickens |
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| ****Occurs in older birds via inhalation of ''E. coli'' in dust; respiratory infection spreads to the blood to cause acute colisepticaemia | | ****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 | | ****Airsacculitis, pericarditis and perihepatitis during acute phase |
− | ****Often secondary to virus or [[Mycoplasmas|''mycoplasma'']] infection or environmental stress | + | ****Often secondary to virus or [[:Category:Mycoplasmas|''mycoplasma'']] infection or environmental stress |
| **'''Colisepticaemia''': | | **'''Colisepticaemia''': |
| ***Systemic disease in young calves, piglets, foals, lambs | | ***Systemic disease in young calves, piglets, foals, lambs |
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| ***Virulence related to adhesive properties, complement resistance and ability for iron aquisition | | ***Virulence related to adhesive properties, complement resistance and ability for iron aquisition |
| ***Ammonia, dust, viral infections and temperature changes enhance likelihood of disease | | ***Ammonia, dust, viral infections and temperature changes enhance likelihood of disease |
− | **[[Stomach and Abomasum - Inflammation#Oedema Disease In The Pig|'''Oedema disease of pigs''']]: | + | **[[Oedema Disease|'''Oedema disease of pigs''']]: |
− | ***Acute, frequently fatal enterotoxaemia of weaned pigs
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− | ***Associated with particular haemolytic serotypes of ''E. coli''
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− | ***Verotoxin (Shiga toxin II e) released in the small intestine and carried in the bloodstream
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− | ***Haemolysin production
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− | ***Subcutaneous and subserosal oedema
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− | ***Peracute disease affecting particulary healthy piglets
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− | ***Mortality rate 30%-90%
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− | ***Antimicrobial treatment effective if administered in time
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| **'''Watery mouth of lambs''': | | **'''Watery mouth of lambs''': |
| ***Affects lambs under three days old | | ***Affects lambs under three days old |
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| ***Severe depression, anorexia, salivation and abdominal distension | | ***Severe depression, anorexia, salivation and abdominal distension |
| ***Morbidity and mortality high | | ***Morbidity and mortality high |
− | ** [[Intestines - Inflammatory Bowel Disease And Related Conditions#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 [[Peritoneal cavity - inflammatory#In dogs|peritonitis in dogs]] and [[Peritoneal cavity - inflammatory#In pigs|peritonitis in pigs]] | + | ** Causes [[Peritonitis - Cats and Dogs|peritonitis in dogs]] and [[Peritonitis#In pigs|peritonitis in pigs]] |
− | **Found in [[Bones - inflammatory#Osteomyelitis|osteomyelitis]] | + | **Found in [[Osteomyelitis|osteomyelitis]] |
− | **Associated with neonatal [[Joints - inflammatory#In Cattle|polyarthritis of calves]] | + | **Associated with neonatal [[Infectious Arthritis#In Cattle|polyarthritis of calves]] |
− | **Found in [[Joints - inflammatory#In Horses|arthritis of horses]] | + | **In [[Deep Pyoderma|deep pyoderma]] |
| + | **Found in [[Infectious Arthritis#In Horses|arthritis of horses]] |
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− | ===Intestinal infection===
| + | ==Intestinal infection== |
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| *''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 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]] |
− | *Enterotoxigenic ''E. coli'' (ETEC): | + | |
| + | |
| + | *'''Enterotoxigenic ''E. coli'' (ETEC)''': |
| **General: | | **General: |
− | *** Contributes to [[Intestines - Catarrhal Enteritis#Undifferentiated Neonatal Calf Diarrhoea|undifferentiated neonatal calf diarrhoea]], a mixed viral enteritis in calves, also known as enteric colibacillosis | + | *** Contributes to [[Calf Diarrhoea, Undifferentiated Neonatal|undifferentiated neonatal calf diarrhoea]], a mixed viral enteritis in calves, also known as enteric colibacillosis |
| ***Causes scours in pigs, calves and lambs | | ***Causes scours in pigs, calves and lambs |
| ***'Traveller's diarrhoea' in humans | | ***'Traveller's diarrhoea' in humans |
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| ***K88 (F4) is associated with adhesion to the small intestinal mucosa of pigs | | ***K88 (F4) is associated with adhesion to the small intestinal mucosa of pigs |
| ***K99 (F5) associated with adhesion in pigs and cattle (these fimbrial adhesins were originally thought to be capsular (K) antigens) | | ***K99 (F5) associated with adhesion in pigs and cattle (these fimbrial adhesins were originally thought to be capsular (K) antigens) |
− | ***The fimbriae are encoded by plasmids | + | ***The '''fimbriae are encoded by plasmids''' |
| ***These strains carry a plasmid which encodes an enterotoxin | | ***These strains carry a plasmid which encodes an enterotoxin |
− | ***Two types of enterotoxin: heat-labile (LT) and heat-stable (ST) toxins | + | ***Two types of '''enterotoxin: heat-labile (LT) and heat-stable (ST) toxins''' |
− | ***The plasmids which produce these toxins are responsible for the pathogenicity of these strains | + | ***The '''plasmids''' which produce these toxins are '''responsible for the pathogenicity''' of these strains |
− | ***LT is an oligometric toxin composed of an enzymatically-active A subunit (30KDa; 2 fragments - A1 and A2) and 5 identical B subunits (12KDa) forming the binding portion (B oligomer) | + | ****'''LT''' |
− | ***It attaches to the brush border of the epithelial cells of the small intestine | + | *****An oligometric toxin composed of an enzymatically-active A subunit (30KDa; 2 fragments - A1 and A2) and 5 identical B subunits (12KDa) forming the binding portion (B oligomer) |
− | ***LT causes ADP-ribosylation of the stimulatory subunit of guanine nucleotide binding proteins of the adenylate cyclase complex in eukaryotic cell membranes | + | *****It attaches to the brush border of the epithelial cells of the small intestine |
− | ***This causes irreversible activation of adenylate cyclase in target cells | + | *****Causes ADP-ribosylation of the stimulatory subunit of guanine nucleotide binding proteins of the adenylate cyclase complex in eukaryotic cell membranes |
− | ***This raises the cAMP level and causes hypersecretion of water and chloride ions into the lumen of the small intestine and inhibits reabsorption of sodium | + | *****This causes irreversible activation of adenylate cyclase in target cells |
− | ***ST activates guanylate cyclase in enteric epithelial cells, stimulating fluid secretion | + | *****This raises the cAMP level and causes hypersecretion of water and chloride ions into the lumen of the small intestine and inhibits reabsorption of sodium |
| + | ****'''ST''' |
| + | *****Activates guanylate cyclase in enteric epithelial cells, stimulating fluid secretion |
| **Clinical signs: | | **Clinical signs: |
− | ***The gut becomes distended with fluid and a [[Intestines - diarrhoea#Secretory Diarrhoeas|secretory diarrhoea]] which lasts several days results | + | ***The gut becomes distended with fluid and a [[Diarrhoea#Secretory Diarrhoeas|secretory diarrhoea]] which lasts several days results |
| ***Watery diarrhoea, dehydration, acidosis, death | | ***Watery diarrhoea, dehydration, acidosis, death |
− | **Immunuty: | + | **Immunity: |
| ***LT is antigenic | | ***LT is antigenic |
| ***Immunity is developed via production of antibody to LT protein and fimbrial antigen | | ***Immunity is developed via production of antibody to LT protein and fimbrial antigen |
| ***Parenteral vaccination of pigs and cattle protects offspring from scours via antibody production in the colostrum (passive immunity) | | ***Parenteral vaccination of pigs and cattle protects offspring from scours via antibody production in the colostrum (passive immunity) |
| ***ST is not immunogenic; it is small, with only 19 amino acids | | ***ST is not immunogenic; it is small, with only 19 amino acids |
− | *Enteropathogenic ''E. coli'' (EPEC): | + | |
− | **Attching and effacing strains of ''E. coli'' | + | |
| + | *'''Enteropathogenic ''E. coli'' (EPEC)''': |
| + | **Attaching and effacing strains of ''E. coli'' |
| **Attach to small intestinal epithelial cells and cause necrosis of enterocytes and stunting and fusion of villi | | **Attach to small intestinal epithelial cells and cause necrosis of enterocytes and stunting and fusion of villi |
| **Possess ''E. coli'' adherence factor plasmid | | **Possess ''E. coli'' adherence factor plasmid |
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| **Intracellular calcium levels increase and production of protein kinase C causes loss of chloride ions and water from the intestinal epithelial cells | | **Intracellular calcium levels increase and production of protein kinase C causes loss of chloride ions and water from the intestinal epithelial cells |
| **Diarrhoea results | | **Diarrhoea results |
− | *Enteroinvasive ''E. coli'': | + | |
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| + | *'''Enteroinvasive ''E. coli''''': |
| **Cause colisepticaemia in calves during their first week of life; occasionally in lambs, piglets and puppies | | **Cause colisepticaemia in calves during their first week of life; occasionally in lambs, piglets and puppies |
| **Infection via ingestion or umbilicus; inadequate colostrum increases susceptibility | | **Infection via ingestion or umbilicus; inadequate colostrum increases susceptibility |
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| **Abscesses, pneumonia in long term | | **Abscesses, pneumonia in long term |
| **Death occurs in absense of treatment | | **Death occurs in absense of treatment |
− | *Enterohaemorrhagic ''E. coli'': | + | |
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| + | *'''Enterohaemorrhagic ''E. coli''''': |
| **Possibly carried by cattle | | **Possibly carried by cattle |
| **Produce shiga-like toxin, a vero toxin | | **Produce shiga-like toxin, a vero toxin |
| **Plasmid-coded fimbriae important for virulence | | **Plasmid-coded fimbriae important for virulence |
− | **Intimin produced allowing intimate attchment to intestinal epithelial cells | + | **Intimin produced allowing intimate attachment to intestinal epithelial cells |
| **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 |
− | **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 |
− | *Cytotoxin necrotising factor-producing ''E. coli'' | + | |
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| + | *'''Cytotoxin necrotising factor-producing ''E. coli''''' |
| **Infrequently cause diarrhoea in calves, pigs and humans | | **Infrequently cause diarrhoea in calves, pigs and humans |
| **Important virulence factors include toxin and fimbriae | | **Important virulence factors include toxin and fimbriae |
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| + | ==in cattle== |
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| + | *Neonatal polyarthritis: |
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| + | **[[Escherichia coli|'''''Coliforms''''']] |
| + | ***Localises in joints and meninges in severe non-fatal neonatal colibacillosis |
| + | ***May remain as chronic arthritis in larger joints |
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| + | [[Category:Enterobacteriaceae]] |
| + | [[Category:To_Do_-_Bacteria]] |