escherichia Flashcards
Escherichia are gram what?
gram-negative
Escherichia shape
bacilli
what temp do Escherichia like
mesophilic
do Escherichia form spores
No
Escherichia relationship with oxygen
facultative anaerobes
Escherichia make up what % of human GI flora
0.1 %
what is the “claim to fame” of Escherichia
conversion of digested K1 into K2
Vitamin K2 is
it’s active form in humans
how many species in the Escherichia genus
5-6 known
Escherichia can divide in
just 20 minutes
a newborn’s intestine will typically be colonized with Escherichia within
40 hours of birth
who discovered Escherichia
Theodor Escherich in 1886
E. coli is most linked to what categories of disease
- infection of GI tract
- Urinary Tract Infection
- Meningitis
E. coli cause infection of the GI tract gist
colonization of virulent strain in GI tract can cause bad things
what bad things can colonization of virulent strains of E. coli in GI tract cause
diarrhea and dysentery
dysentery
diarrhea with blood
E. coli is responsible for how much of UTIs
about 85%
how does E. coli cause a UTI
passed from the fecal/oral route to the urethra or bladder
E. coli is how much more commen in girls
14x … urethra is shorter
Meningitis caused by E. coli is usally only commono in
neonates, requires entry into the bloodstream plus the K1 antigen
what does the K1 antigen help E. coli do in meningitis
helps it pass through the BBB (brain blood barrier) into the meninges
how does E. coli spread
through the fecal-oral route
what does it mean that E. coli spreads through the fecal-oral route
feces of fecal matter infected materials must enter the mouth of someone
how does the fecal-oral route usually spread
dirty water or inadequate hand-washing after using the bathroom
E. coli spread is closely linked to what food
ground beef
most important species of Escherichia is
Escherichia coli
E. coli comes in many different
serotypes
serotypes
different strains catalogued by their surface antigens (think lancefield)
Escherichia coli serotypes are grouped based on what surface antigens
Oligosaccharides
Flagellal structure
Capsule
Escherichia coli serotypes are grouped based on what surface antigens KNEUMONIC
O- Oligosaccharides
H-Flagellal structure
K - Capsule
Oligosaccharides as a surface antigen of E. coli
structure of sugar chains at the outer tip of LPS
how many LPS structures known in E. coli
173
how many unique flagellal structures known of E.coli
53
Capsule E.coli
he structure of the protein on the outermost layer of E. coli
how many unique structure known capsule e. coli
60
serotypes of E. coli are another example of
antigenic variation
leading disease-causing stereotype of E. coli
E. coli O157 : H7
and K antigen does not matter in this case
O antigen is
Oligosaccharides, somatic `
E. coli, being negative…. have
many fimbriae
most important type of fimbriae that E. coli have
type I fimbriae
type 1 fimbriae
ecspecially sticky to cells that line the small intestine and/or bladder
type 1 fimbriae allow
bacteria to stick to cells that line the small intestine and/or bladder
once E.coli sticks to cells that line the small intestine and/or bladder
secrete an exotoxin
which exotoxins would E.coli secrete once attached to cells that line small intestine and or bladder
LT, STa, or STb
E.coli secreting exotoxins LT, STa, or STb»» would
increase levels of cGMP in the intestine
when levels of cGMP are increased in the intesine by E coli
- stopping water absorption in the intestines,
- leaving more fluid in the intestinal lumen and triggering diarrhea.
one dominant virulence factor of very bad E coli
Stx
Stx
shiga toxin
Virulent E. coli express that shiga toxins
Stx1 or Stx2
Stx2 compared to Stx1
400 times as potentt
what an exotoxin agin???
secreted proteins
what do Stxs first do when release
receptors on human intestinal endothelial cells to enter the cells
the receptors on intestinal endothelial cells that Stxs bind to
NOT FOUND IN ANIMALS
since the the receptors on intestinal endothelial cells that Stxs bind to are not found in animals
allows virulent strains to grow in animals harmlessly before humans consume them
when shiga toxin enters human intestinal endothelial
one part of a shiga toxin binds to and cleaves an important part of ribosomes in those endothelial cells, halts function
if endothelial cells have no functioning ribosomes
no proteins»> cell death
what receptors do shiga toxins bind to….maybe
GB3
most dangerous E. coli strains like O157 : H7 are called
enterohemorrhagic
what does it mean to be enterohemorrhagic
disrupt the GI tract and cause hemorrhage (bleeding)
what sometimes causes E. coli to be enterohemorrhagic
cell death from Shiga toxin
other times, what causes E. coli to be enterohemorrhagic
protein enterohemolysin
enterohemolysin
breaks apart blood, only acts in intestines
REALLY BAD E. COLI STRAINS
can carry both the genes for a Shiga toxin and enterohemolysin
some E. coli strains re linked to what syndrome
hemolytic uremic syndrome
in hemolytic uremic syndrome there is
broken down blood (from hemolysins) and/or tissue (from shiga toxins
hemolytic uremic syndrome broken down blood and or tissue leads too
mini-clots forming, traveling, and eventually and clogging capillaries
clots from hemolytic uremic syndrome
clots spread through the body usually have the biggest impact on kidneys
clots from hemolytic uremic syndrome effect on kidneys
begin to fail and die
end result of hemolytic uremic syndrome
blood in the urine that onsets 5-10 days after initial E. coli onset
E. coli causes what % of UTIs
85%
in UTIs caused by E. coli, bacteria
get into the urinary tract
when E. coli enters the urinary tract…
problems begin if they hit the bladder
E. coli in the urinary tract can move even
further upstream to the ureters or kidneys
symptoms of UTI caused by E. coli
- strong urge to urinate
- unproductive urination
- cloudy urine
treatment E. coli
antibiotics.. but resistance is becoming a problem…
