Lecture 17 - Escherichia Coli Flashcards
Enterobacteriacea: gram
negative
Enterobacteriacea: morphology
rods
Enterobacteriacea: catalase
positive
Enterobacteriacea: oxidase
negative
E. Coli: fermentation
Lactose
E. Coli: hemolysis
Beta
What is E. coli commonly responsible for? (very basic answer, think location)
Extraintestinal disease
What is important to know about E. coli that causes enterocolitis?
NOT normal flora
What are the four serotypes in e. coli?
O - H - K - F
E. Coli: O antigen
Somatic - LPS
E. Coli: H antigen
Flagellar - Protein
E. Coli: K antigen
Capsular - polysacchrides
E. Coli: F antigen
Fimbrial - Protein
What is the major E. coli responsible for zoonosis?
E. Coli O157:H7
What does E. coli O157: H7 cause?
Hemorrhagic colitis
Hemolytic uraemic syndrome
What is the usual source of E. coli outbreaks?
Manure + Fecal material of infected cows
What are the two groups of E. coli’s?
Enteric + Extraintestinal
What are the enteric strains of E. coli?
ETEC
AEEC
EAggEC
What does ETEC stand for?
Enterotoxigenic
What does AEEC stand for?
Attaching and Effacing
What does EAggEC stand for?
Enteroaggregative
What are the types of AEEC?
EPEC + STEC
What does EPEC stand for? What are the subtypes?
Enteropathogenic - Atypical and Typical
What does STEC stand for? What are the subtypes?
Shiga-toxin producing - EHEC EnteroHEMOrrhagic
What are the extraintestinal strains of E. Coli?
APEC
SEPEC
UPEC
What does APEC stand for?
Avian Pathogenic
What does SEPEC stand for?
Septicemic pathogenic
What does UPEC stand for?
Uropathogenic
What are the four categories of virulence factors?
Capsular polysaccharides
Endotoxins
Fimbrial attachments
Secreted toxins
What types of toxins are secreted from E. coli?
Enterotoxin
Shigatoxin
Cytotoxic necrotizing factors
What is another name for shigatoxin?
Verotoxin
What is the function of the fimbrial attachments?
Attachment to mucosal + epithelium surfaces
What is another type of adhesion besides fimbrial?
Intimin + EAF + CS31A
What does the attachment of the bacteria cause in the host?
Actin pedestals form the actin rearrangement
What is LPS (endotoxin) made up of?
Lipid A - Polysaccharide + Side chains
What does LPS cause in the body?
Pyrogenic activity
Vascular coagulation
Shock
What does the capsule do in aidding in infection of E. Coli?
Makes the bacteria slippery
Complement + Phagocytes can’t bind
What E. Coli uses Cs31A adhesion?
SEPEC - sepecemtic pathogen
Where is the surface antigen for CS31A found?
Calves
What E. Coli uses EAF?
EPEC - Enteropathogenic
What E. Coli uses Fimbrial adhesions?
EAggEC - AA fimbriae
What E. coli uses Intimin?
AEEC - Attaching and effacing
How does intimin work?
Attaches to host cell and via T3SS will inject Tir proteins
Host cell will present Tir receptors
E. Coli attaches –> actin pedestal forms
What does the actin pedestal allow for?
Very strong adhesion by E. Coli
Prevents washing off
What does the actin pedestal cause pathogenically in the animal?
Premature enterocyte exfoliation - diarrhea
What genetic feature do AEEC have?
Pathogenicity islands LEE
What are pathogencitiy island LEE required for?
needed for bacteria to be virulent
What does LEE stand for?
Locus of enterocyte effacement
What does LEE encode for?
Intimin + TiR + T3SS
What are the two categories of enterotoxins, besides cytotoxic necrotizing factors?
Heat-labile (LT) + Heat-stable (ST)
What types of E. coli enterotoxins are Heat-labile?
Shigatoxin + LT1 + LT2
What types of E. Coli enterotoxins are Heat-stable?
STa + STb + EAST1
What are the two E. Coli strains that have LT toxins?
STEC - Shiga toxin producing
ETEC - Enterotoxigenic
What animals are affected by the LT toxins?
Pigs + Cattle
What LT toxin affects cattle? What E. coli strain?
LT2 - ETEC (enterotoxigenic)
What are the two toxins that affect pigs? What E. Coli strains?
STEC - Shiga-toxin
ETEC - LT1
What does LT1 bind to in pigs?
K88 receptor
What does LT1 binding induce?
Hypersecretion of fluids
What does Shigatoxin cause in pigs?
Enterocytotoxic + Neurotoxic
Hemorrhage + Edema + Thrombosis
What does shigatoxin do biochemically?
Binds to and inactivates ribosomes
Stop protein synthesis –> cellular death
What point in a pigs life cycle are K88 receptors expressed the most?
Young
What E. coli strain contains STa?
ETEC - enterotoxigenic
What animals does the STa toxin infect?
Cattle + Pigs + Sheep
What does STa toxin cause?
Hypersecretion + Malabsorption of fluid
What does the STb toxin cause?
Hypersecretion + Malabsorption
What does EAST1 stand for?
Enteroaggregative heat stable toxin
What E. coli contains EAST1 toxin?
ETEC - enterotoxigenic
EPEC - Enteropathogenic
EHEC - Enterohemorrhagic
EAggEC - Enteroaggregative
What is important to note about EAST1 toxin?
ENHANCES hypersecretion + malabsorption
Does not produce problems on its own
What two animals most commonly experience enteric colibacillosis?
Pigs + Calves
When do pigs come down with enteric colibacillosis? What are the symptoms?
Within 24 hours of birth
Watery diarrhea + Dehydration + Weakness + Death
What is seen in calves with enteric colibacillosis?
Dehydration + Death + Diarrhea
What is a big sign that your calf has enteric colibacillosis?
Diarrhea is watery + pasty + white/yelllow + Rancid
What two E. coli are responsible for enteric colibacillosis?
AEEC + ETEC
What does AEEC cause in enteric colibacillosis?
Necrosis of enterocytes + loss of microvilli
What does ETEC bind to in enteric colibacillosis?
K88 + K99 fimbrial adhesins
What two toxins does ETEC secrete that cause enteric colibacilosis?
LT1 + STa
What is another term for diarrhea in pigs and cattle?
Scour
What animals do you see Colisepticemia?
Lambs + Calves + Poultry
What disease is seen in lambs with colisepticemia?
Watery mouth
What are the symptoms of Water mouth in lambs?
Profuse salivation + Distended abdomen
Endotoxic shock
High mortality
What does the severity of colisepticemia in calves correspond with?
Degree of hypo-Ig
What do you see in calves that have recovered from colisepticemia?
Post-septicemic localization to joints
What is seen in poultry with colisepticemia?
Airsacculitis
Pericarditis
Coligranuloma
What disease does Coligranuloma cause in poultry with colisepticemia?
Hjarre’s disease
Chronic inflammation
What animal do you see edema disease in?
Pigs
What causes the onset of edema disease?
Shigatoxin in the blood stream leading to perivascular edema
What is a sign that a pig is suffering from edema disease?
Eyelid swelling
Hoarse squeal due to swelling of the larynx
When does edema disease in pigs tend to occur?
1 to 2 weeks post weaning
What happens within 36 hours of edema disease onset?
Paralysis - peracute death
What happens commonly when a pig survives edema disease?
CNS defects
What is seen in cattle that are affected with e. coli (females)?
Coliform mastitis
What do the milk secretions look like in cattle with e.coli infections?
Watery with white flakes
How long does coliform mastitis become fatal in cattle?
24 to 48 hours
What does a cattle with coliform mastitis look like physically?
Depressed
Drooping ears + sunken eyes
What kind of urogenital infections does E. Coli cause?
UTI + Cystitis
Pyometra
Prostatitis
What animals experiences post-weaning diarrhea from E. coli?
Pigs
What e. coli strains are responsible for PWD?
ETEC - enterotoxigenic
EPEC - enteropathogenic
What is big sign that a pig is suffering from PWD?
Diarrhea with purple discolored patches of skin
How do you know that the pig is suffering from PWD rather then Salmonella?
Purple patches all over rather then just ears
What specific assay is for E. Coli?
Vero cell assay
What specific characteristics does e. coli have?
Motile Lactose fermentation Imdole Methyl-red Lysine decarboxylase
What does E. Coli look like when it grows on MacConkey?
Red agar/colonies
Lactose fermentor
What are the TSI results for E. Coli?
All yellow
No H2S production
GAS!
What is an important way to prevent E. Coli infections in cattle?
COLOSTRUM!
What animals have access to E. Coli vaccines?
Cattle + Pigs + Poultry