E.Coli Flashcards
Ferment lactose rapidly
Produce indole
There are over 150 strains of “O, K and H antigens
E. Coli
one of the most important virulence factor of E.coli
PILI (virulence factor) express tropism
What type of Pili binds to D-mannose
Type 1 Pili
Important type of pili that adheres to Digalactoside (Gal-gal)
binds to “uroepithelial” cells
P type pili
Name the major toxins of E.coli
Alpha hemolysin
CNF
Shiga toxin
LT -labile
ST -stable
Mechanism:
Alpha hemolysin: pore forming
CNF: A,B toxin interupts G protein (activation and inactivation states)
Shiga: produced by Shigella and e.coli
LT: + Adenylate Cyclase causes watery diahrhea (water and electrolyte loss)
ST: + Guanylate Cyclase: small peptide cause diarrhea (water and electrolyte loss)
Manifestations of E.coli in newborns
NOTE: involves sirface antigen K capsule identical to meningococcus
sepsis
Meningitis
because of bacterial colonization of the mother’s vagina
Uropathic strains characterized by pili with adhesin proteins bind to specific receptors on urinary tract epithelium:
The binding site consist of what ?
The pili is called P fimbria associated with pyelonephritis
Dimers
Gal-gal
Causes uncomplicated UTI to travel up the kidneys
Treatment for E.Coli uncomplicated UTI
Cystitis
Trimethorphim-Sulfamethoxazole or Nitrofurantoin
- Treatment for E.coli pyelonephritis
- Tx for neonatal meningitis
1.Cipro
Ceftriaxone
2. Ampicillin and Cefotaxime
Diagnosis of E.Coli
Traits
blood agar plate
Mac Conkey
green sheen
produces tryptophan
decarboxylate lysin
motile
Trait: Green sheen
Types of E.coli INTESTINAL infections
ETEC: toxigenic: associated with traveller’s diarrhea
EPEC: pathogenic Cytoskeleton modification A/E lesion
EHEC: hemorrhagic ( HUS)
These are caused by exotoxin produced by E.coli enterotoxin
Common manifestations to keep in mind
Meningitis in neonates
UTI (cystitis)
traveler’s diarrhea
pyelonephritis
Major virulence factor is pili type 1 and P pili
