E. Coli Flashcards
Questions to ask How can u prevent it? is there a vaccine? Who's at risk/ what's the epi? How do u treat it? how do u diagnose it? Pathogensis? symptoms/ disease? I. Mechanisms of Pathogenesis A. Type 3 Secretion System (T3SS) common pathogenic mechanisms emerge, including interference with the host cell cytoskeleton to promote attachment and invasion, interference with cellular trafficking processes, cytotoxicity and barrier dysfunction, and immune system subversion. http://cmr
STEC
shiga-toxin producing E.Coli
also known as EHEC
EHEC
enterohemorrhagic
only hemhorragic strain
EPEC
enteropathogenic e. coli
diarrheogenic
EAEC
enteroaggregative e. coli
diarrheogenic
EIEC
enteroinvasive e. coli
diarrheogenic
ETEC
enterotoxigenic e. coli
diarrheogenic
path: HUS- hemolytic uremic syndrome
the infection stimulates platelet formation in microvasculature. movement past the platelets shears red blood cells
shishtocytes
path: microangiopathy
platelets lodged in microvasculature shear RBCs into fragments called schistocytes
path: schistocytes
red blood cell fragments produced during HUS
path: T3SS
Type III Secretion System
bacteria are able to directly inject bacterial proteins called effectors into host cells across bacterial and host membranes, where they can manipulate host cell function.
common pathogenic mechanisms emerge, including interference with the host cell cytoskeleton to promote attachment and invasion, interference with cellular trafficking processes, cytotoxicity and barrier dysfunction, and immune system subversion.
path: G3b
the receptor for shiga toxin (vascular endothelium)
*cattle are different/ resistant
path: STX (shiga-like toxin) B subunit
binding subunit (vascular endothelium)
path: STX (shiga-like toxin) A subunit
halts protein synthesis inside vascular endothelial cells
path: LEE
locus of enterocyte effacement
a pathogenecity island
path: T3SS effectors
injected proteins
ex. tir and intimin
path: RTX
repeats in toxin
pore forming proteins
path: k-antigen
capsule
path: LT toxin
targets cAMP and leads to excess secretion of Cl- secretion
*similar to cholera toxin
EAST
enteroaggregative stable toxin
path: plasmid encoded toxin
poorly characterized
EHEC: path
- shiga toxin
- hemolysins
- A/E
EPEC: path
A/E, bfp
ETEC: path
- ST: heat-stable toxin
- LT; heat labile toxin
- fimbrae
EAEC: path
- hemolysins
2. EAST
EIEC: path
- nonfimbrae adhesins
DAEC: path
diffuse-adherence factors
DAEC: presentation
diarrhea in children
EIEC: presentation
watery diarrhea with blood and mucus
EPEC: presentation
infantile diarrhea
ETEC: presentation
traveler’s diarrhea
EHEC: presentation
- bloody diarrhea
2. HUS
EAEC: presentation
EPEC
watery diarrhea in children of developing countries
EHEC: treatment
supportive care only
ETEC: treatment
- loperamide
- azithromycin
- rifaximin
EPEC: treatment
anti-biotics based on susceptibility tesitng
EAEC: treatment
fluorquinolones
