Bordetella, Enterobacteriaceae Flashcards
explain the structure of bordetella pertussis
EXTREMELY SMALL
gram negative
coccobacillus
what conditions does bordetella pertussis grow in? does it ferment?
STRICT AERBOBE
nonfermentive. it OXIDIZES amino acids
what is the major clinical disease caused by bordetella pertussis
whooping cough (aka pertussis)
as mentioned, bordetelle pertussis oxidizes amino acids.
this is also known as the ____ pathway. it is required for the bacteria to ______
nicotinamide pathway
required for the bacteria to GROW
is b. pertussis encapsulated
NO but it has adherence factors
as mentioned, B. pertussis does not have a capsule, but is has adhesions to adhere to the host.
name these adhesins
pertactin
filamentous hemagglutinin
fimbriae
pilli
name the toxins of b. pertussis
Pertussis toxin (A-B toxin)
adenylate cyclase toxin/hemolysin
dermonecrotic toxin
tracheal cytotoxin
LPS (lipid A or Lipid X)
explain how the pertussis toxin works
it is an A-B toxin
B subunits bind cell surface proteins
A subunit inactivates Gi (ADP ribosylation of G protein) which INCREASES CAMP and increases secretions
explain what dermonecrotic toxin and tracheal cytotoxin do
dermonecrotic toxin —-it is a heat labile toxin. could be inactivated when exposed to heat. causes VASOCONSTRICTION
tracheal cytotoxin – it is a peptidoglycan monomer. inhibits the cilia. causes the cell to get extruded out of the cellular layer and into the mucus (CELL DEATH)
What bordetella toxin EXTRUDES the cells infected with b. pertussus?
tracheal cytotoxin
is there any potential for bacteremia for bordetella pertussis?
yes
is pertussis disease fast acting or slow acting
pretty slow acting. has an incubation period of 7-10 days
during what stage of pertussis disease is the bacterial culture the HIGHEST
catahhral
what is the largest family of clinically important bacteria?
enterobacteriaceae
where are enterobacteriacea found
water, soil, and endogenous flora
how can enterobacteriaceae be classified?
3 types—
strictly pathogens (not part of commensal)
opportunistic
commensals that acquire virulence gene or novel body niche
enterobacteriaceae commensals can acquire a virulence gene if there is ____ gene transfer
horizontal
true or false
most species and subspecies of enterobacteriaceae are NOT human pathogens
true
what are the 3 medically important enterobacteriaceae?
-escherichia coli
-shigella
-salmonella
what are the diagnostic antigens of escherichia voli
O,H,K
how are different strains of escherichia coli classified?
based on their diagnostic antigens (O,H,K)
what are the 5 strains of e. coli that cause diarrheal disease?
ETEC (entertoxigenic)
EPEC (enteropathogenic)
EHEC (enterohemorrhagic)
EIEC (enteroinvasive)
EAEC (enteroaggregative)
what is the most highly infective e. coli strain, responsible for a lot of outbreaks? give details on their diagnostic antigens
EHEC (enterohemorrhagic)
O157:H7
explain the growth conditions of the enterobacteriaceae family.
do they form spores?
are they gram positive or negative?
shape?
FACULTATIVE ANAEROBED – they generally ferment
non spore forming
gram negative rods
do enterobacteriaceae contain oxidase? what about catalse?
no oxidase
yes catalase
true or false
enterobacteriacea have cytochrome oxidase activity
FALSE – they do not
are enterbacteriaceae motile?
some are motile
explain further how e. coli are classified
based on their surface antigens
O polysaccharides are a subunit of LPS
K antigens are capsule polysaccharides
H proteins are flagellar proteins
e. coli can adhere to many different cells.
explain
there are a variety of pili at one time that can be on their surface.
type 1 is the common pilli on all of the e. coli strains
what is the COMMON toxin to all e. coli strains
endotoxin – lipid A component of LPS
are all e. coli encapsulated?
yes
do e. coli have a secretion system?
which ones?
they ALL have a type 3 secretion system
what is a unique property, common to all e. coli strains
ability to do antigenic phase variation
they can turn genes on and off to express different O and H antigens, and K proteins to make their outer surface look different
true or false
all e. coli strains have a common endotoxin
TRUE – they are gram negative so they all share the lipid A component of LPS
ENTEROBACTERIACEAE ARE THE MOST COMMON GRAM NEGATIVE RODS FOUND IN ________ cases
SEPSIS —- frequently cause bacteremia
how can e. coli be transmitted
MANY different ways – through food, fecal oral route, animals, through abcesses, through vaginal cavity
what bacteria causes >80% of commonly acquired UTIs?
e. coli – specifically UPEC (uropathogenic ecoli)
what are the 3 extraintestinal diseases caused by e. coli
bacteremia
neonatal meningitis
UTI
what makes UPEC very good at causing UTIs?
they are able to adhere to the perineum through their type 1 pilli
once they make their way into the bladder, they can create a balance between ADHESION and MOTILITY by switching genes on and off.
in order to bind in the bladder, they need to find a spot with type 1 pili receptor AND p pilli receptor.
they move with their flagella until they find a spot like this. once they find it, they STOP USING THEIR FLAGELLA and TURN ON P PILLI AND TYPE 1 PILLI genes to bind
they then multiple and divide in the bladder. bc they are mobile, they can move up the ureter and establish a kidney infection as well
is mentioned, UPEC is a very common UTI infector.
name the specific infections it can cause
cystitis (bladder infection) and pyelonephritis (kidney infection)
E. coli are a major contributor to ____ illness
diarrheal
of the 5 e. coli strains that cause diarrhea, which cause watery diarrhea and which cause bloody diarrhea
watery diarrhea: ETEC, EPEC
bloody diarrhea: EHEC EIEC
watery AND bloody diarrhea: EAEC
5 strains of e.coli cause intestinal infections and diarrheal illness.
how do they come about? name 2 ways
-opportunistic commensal activity
-from contaminated food or water
which e. coli strain causes “traveler’s diarrhea”
enterotoxigenic e. coli (ETEC)
what is the ETEC pilli
CF (colonizing factor)
what are the ETEC toxins
ST (heat stable toxin)
LT-I (heat liable toxin)
explain the structure and function of heat stable toxin (ST)
what e.coli strain is it a part of?
ETEC
it is a monomeric peptide, meaning it is very hard to inactivate as opposed to a peptide. thus heat stable
it binds guanylate cyclase, leading to increased cGMP and hypersecretion of ions out of cell (same effect as hypersecretion of cAMP)
LT-I toxin (heat liable toxin) is part of which strain of e. coli?
it is similar to what other toxin?
how does it work?
ETEC
similar to cholera toxin
an exotoxin (AB toxin)
the B subunit binds surface glycoproteins
A subunit binds adenylate cyclase leading to increased cAMP and hypersecretion and decreased absorption, leading to diarrhea
what is the pilli for EPEC
bundle-forming pilli (Bfp)
which strain of e. coli has a “locus of enterocyte effacement” pathogenicity island?
what does this pathogenicity island contain?
EPEC
contains 40 genes that cause attachment and destruction of the host cell surface. they cause A/E lesions (attachment and effacing legions). the major ATTACHMENT protein is Intimin
also has a type III secretion system that injects Esps (E. coli secretion proteins) into the cell
explain how EPEC causes A/E lesions
Esps (E. coli secretion proteins) are injected into the cell with a type III secretion system (nanosyringe). this causes the proteins in the cell to remodel the cytoskeleton into a PEDESTAL in the infected cell
the presence of an intestinal cell with a pedestal indicates infection by which bacteria?
EPEC (enteropathogenic e. coli)
