Facts about Pathogenic Escherichia coli: Flashcards
what important common features does pathogenic Escherichia coli strains have?
- Lactose Fermenter (pink on MacConkey)
- Strict pathogens cause GI infections
all strains will be identified using what E. coli biology facts?
Gram negative bacilli
Motile
Lactose fermenter
Oxidase negative
Catalase +
what are the 4 clinical diseases Escherichia coli causes?
1) Entero Toxin E. coli (ETEC)
2) Entero Pathogenic E. coli (EPEC)
3) Entero-Invasive E. coli (EIEC)
4) Entero-Hemorragic E. coli (EHEC)
how does EPEC spread?
fecal-oral in developing countries
how does ETEC spread?
fecal-oral in developing countries
how does EIEC spread?
fecal-oral in developing countries
how does EHEC spread?
through fecal-oral found in beef or produce
In ETEC, what is another name for entero-toxigenic E. coli?
traveler’s diarrhea
what is another name for ETEC, other than traveler’s diarrhea?
Montezuma’s Revenge
what does Entero-toxigenic E. coli do?
it attaches to the small intestine using fimbreae
what 2 entero toxins will cause the symptoms seen with ETEC?
- LT (heat-liable toxin)
- ST (heat-stable toxin)
what is the presentation of Entero-toxic E.coli?
self-resolving profuse watery secretory diarrhea without fever
how does the LT toxin from ETEC cause diarrhea?
it increases levels fo cAMP through activation of adenylyl cyclase.
how does the ST toxin cause profuse watery diarrhea in ETEC?
it activates guanylate cyclase and increases cGMP
what is another name for EPEC (entero-pathogenic e.coli)?
Pediatric diarrhea
where is EPEC common?
in developing countries
what is the pathogenic mechanism of action in EPEC?
EPEC attaches to small intestine using T3SS (attaching and effacing lesions and kills microvilli.
leads to reduced absorption of water leading to symptoms
how does EPEC present clinically?
self-resolving secretory watery diarrhea without fever
what is another name for EIEC?
invasive diarrhea
what is the pathological presentation of EIEC?
EIEC attaches to colon using fimbriae and it rockets from cell to cell causing severe destrion of epithelial layer and releases hemolysin killing RBC’s
what is the clinical presentation fo EIEC?
dysentery (low volume bloody stool with WBC present) with high fever
what is another name for EHEC?
hemorrhaging diarrhea
outbreaks in the US is due to what?
bacteria uses cattle as a reservoir
what is the pathological presentation of EHEC?
EHEC forms A/E lesions in the small intestine causing the diarrhea, then is uses shiga-toxin to destroy endothelial cells leading to the blood in the stool
the shiga toxin found in EHEC, can spread to what other organ endothelial tissue?
kidney
what is the clinical presentation of EHEC?
watery diarrhea followed by profuse bloody diarrhea without fever or WBC
what can EHEC lead to after a while?
Hemolytic Uremic Syndrome
what is EHEC serotype O157:H7 named after?
named based on LPS O and H antigen on its flagella
is EHEC invasive? how is your answer related to fever?
no, which is why fever is most often absent
what symptom is shiga-toxin responsible for?
it is responsible for the destruction of endothelial cells which leads to hemorrhaging
what does shiga toxin do to kill intestinal villi?
cleaves hosts 28s RNA ribosome
on who is hemolytic uremic syndrome most common?
5 years or less on TMP/SMX antibiotics
what is the clinical presentation for hemolytic uremic syndrome?
thrombocytopenia
Microangiopathic hemolytic anemia
Neurological manifestations
in EHEC, where will it not ferment? colonies will look how?
Sorbitol-MacConkey agar (S-Mac), colonies look white
can other e.coli ferment Sorbitol-MacConkey agar (S-Mac)?
yes
what e.coli is this?
EHEC
on what food is EHEC mostly found?
burgers
