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Infectious Disease Final > Bordetella, Enterobacteriaceae > Flashcards

Bordetella, Enterobacteriaceae Flashcards

1
Q

explain the structure of bordetella pertussis

A

EXTREMELY SMALL
gram negative
coccobacillus

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2
Q

what conditions does bordetella pertussis grow in? does it ferment?

A

STRICT AERBOBE
nonfermentive. it OXIDIZES amino acids

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3
Q

what is the major clinical disease caused by bordetella pertussis

A

whooping cough (aka pertussis)

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4
Q

as mentioned, bordetelle pertussis oxidizes amino acids.
this is also known as the ____ pathway. it is required for the bacteria to ______

A

nicotinamide pathway
required for the bacteria to GROW

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5
Q

is b. pertussis encapsulated

A

NO but it has adherence factors

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6
Q

as mentioned, B. pertussis does not have a capsule, but is has adhesions to adhere to the host.
name these adhesins

A

pertactin
filamentous hemagglutinin
fimbriae
pilli

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7
Q

name the toxins of b. pertussis

A

Pertussis toxin (A-B toxin)
adenylate cyclase toxin/hemolysin
dermonecrotic toxin
tracheal cytotoxin
LPS (lipid A or Lipid X)

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8
Q

explain how the pertussis toxin works

A

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

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9
Q

explain what dermonecrotic toxin and tracheal cytotoxin do

A

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)

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10
Q

What bordetella toxin EXTRUDES the cells infected with b. pertussus?

A

tracheal cytotoxin

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11
Q

is there any potential for bacteremia for bordetella pertussis?

A

yes

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12
Q

is pertussis disease fast acting or slow acting

A

pretty slow acting. has an incubation period of 7-10 days

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13
Q

during what stage of pertussis disease is the bacterial culture the HIGHEST

A

catahhral

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14
Q

what is the largest family of clinically important bacteria?

A

enterobacteriaceae

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15
Q

where are enterobacteriacea found

A

water, soil, and endogenous flora

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16
Q

how can enterobacteriaceae be classified?

A

3 types—

strictly pathogens (not part of commensal)
opportunistic
commensals that acquire virulence gene or novel body niche

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17
Q

enterobacteriaceae commensals can acquire a virulence gene if there is ____ gene transfer

A

horizontal

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18
Q

true or false

most species and subspecies of enterobacteriaceae are NOT human pathogens

A

true

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19
Q

what are the 3 medically important enterobacteriaceae?

A

-escherichia coli
-shigella
-salmonella

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20
Q

what are the diagnostic antigens of escherichia voli

A

O,H,K

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21
Q

how are different strains of escherichia coli classified?

A

based on their diagnostic antigens (O,H,K)

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22
Q

what are the 5 strains of e. coli that cause diarrheal disease?

A

ETEC (entertoxigenic)
EPEC (enteropathogenic)
EHEC (enterohemorrhagic)
EIEC (enteroinvasive)
EAEC (enteroaggregative)

23
Q

what is the most highly infective e. coli strain, responsible for a lot of outbreaks? give details on their diagnostic antigens

A

EHEC (enterohemorrhagic)
O157:H7

24
Q

explain the growth conditions of the enterobacteriaceae family.
do they form spores?
are they gram positive or negative?
shape?

A

FACULTATIVE ANAEROBED – they generally ferment

non spore forming
gram negative rods

25
Q

do enterobacteriaceae contain oxidase? what about catalse?

A

no oxidase
yes catalase

26
Q

true or false

enterobacteriacea have cytochrome oxidase activity

A

FALSE – they do not

27
Q

are enterbacteriaceae motile?

A

some are motile

28
Q

explain further how e. coli are classified

A

based on their surface antigens

O polysaccharides are a subunit of LPS
K antigens are capsule polysaccharides
H proteins are flagellar proteins

29
Q

e. coli can adhere to many different cells.
explain

A

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

30
Q

what is the COMMON toxin to all e. coli strains

A

endotoxin – lipid A component of LPS

31
Q

are all e. coli encapsulated?

A

yes

32
Q

do e. coli have a secretion system?
which ones?

A

they ALL have a type 3 secretion system

33
Q

what is a unique property, common to all e. coli strains

A

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

34
Q

true or false

all e. coli strains have a common endotoxin

A

TRUE – they are gram negative so they all share the lipid A component of LPS

35
Q

ENTEROBACTERIACEAE ARE THE MOST COMMON GRAM NEGATIVE RODS FOUND IN ________ cases

A

SEPSIS —- frequently cause bacteremia

36
Q

how can e. coli be transmitted

A

MANY different ways – through food, fecal oral route, animals, through abcesses, through vaginal cavity

37
Q

what bacteria causes >80% of commonly acquired UTIs?

A

e. coli – specifically UPEC (uropathogenic ecoli)

38
Q

what are the 3 extraintestinal diseases caused by e. coli

A

bacteremia
neonatal meningitis
UTI

39
Q

what makes UPEC very good at causing UTIs?

A

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

40
Q

is mentioned, UPEC is a very common UTI infector.
name the specific infections it can cause

A

cystitis (bladder infection) and pyelonephritis (kidney infection)

41
Q

E. coli are a major contributor to ____ illness

A

diarrheal

42
Q

of the 5 e. coli strains that cause diarrhea, which cause watery diarrhea and which cause bloody diarrhea

A

watery diarrhea: ETEC, EPEC
bloody diarrhea: EHEC EIEC

watery AND bloody diarrhea: EAEC

43
Q

5 strains of e.coli cause intestinal infections and diarrheal illness.
how do they come about? name 2 ways

A

-opportunistic commensal activity
-from contaminated food or water

44
Q

which e. coli strain causes “traveler’s diarrhea”

A

enterotoxigenic e. coli (ETEC)

45
Q

what is the ETEC pilli

A

CF (colonizing factor)

46
Q

what are the ETEC toxins

A

ST (heat stable toxin)
LT-I (heat liable toxin)

47
Q

explain the structure and function of heat stable toxin (ST)
what e.coli strain is it a part of?

A

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)

48
Q

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?

A

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

49
Q

what is the pilli for EPEC

A

bundle-forming pilli (Bfp)

50
Q

which strain of e. coli has a “locus of enterocyte effacement” pathogenicity island?
what does this pathogenicity island contain?

A

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

51
Q

explain how EPEC causes A/E lesions

A

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

52
Q

the presence of an intestinal cell with a pedestal indicates infection by which bacteria?

A

EPEC (enteropathogenic e. coli)

53
Q
A

Infectious Disease Final (13 decks)

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