Bordetella, Enterobacteriaceae

Question 1

explain the structure of bordetella pertussis

Answer 1

EXTREMELY SMALL
gram negative
coccobacillus

Question 2

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

Answer 2

STRICT AERBOBE
nonfermentive. it OXIDIZES amino acids

Question 3

what is the major clinical disease caused by bordetella pertussis

Answer 3

whooping cough (aka pertussis)

Question 4

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

Answer 4

nicotinamide pathway
required for the bacteria to GROW

Question 5

is b. pertussis encapsulated

Answer 5

NO but it has adherence factors

Question 6

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

Answer 6

pertactin
filamentous hemagglutinin
fimbriae
pilli

Question 7

name the toxins of b. pertussis

Answer 7

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

Question 8

explain how the pertussis toxin works

Answer 8

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

Question 9

explain what dermonecrotic toxin and tracheal cytotoxin do

Answer 9

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)

Question 10

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

Answer 10

tracheal cytotoxin

Question 11

is there any potential for bacteremia for bordetella pertussis?

Answer 11

yes

Question 12

is pertussis disease fast acting or slow acting

Answer 12

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

Question 13

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

Answer 13

catahhral

Question 14

what is the largest family of clinically important bacteria?

Answer 14

enterobacteriaceae

Question 15

where are enterobacteriacea found

Answer 15

water, soil, and endogenous flora

Question 16

how can enterobacteriaceae be classified?

Answer 16

3 types—

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

Question 17

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

Answer 17

horizontal

Question 18

true or false

most species and subspecies of enterobacteriaceae are NOT human pathogens

Answer 18

true

Question 19

what are the 3 medically important enterobacteriaceae?

Answer 19

-escherichia coli
-shigella
-salmonella

Question 20

what are the diagnostic antigens of escherichia voli

Answer 20

O,H,K

Question 21

how are different strains of escherichia coli classified?

Answer 21

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

Question 22

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

Answer 22

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

Question 23

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

Answer 23

EHEC (enterohemorrhagic)
O157:H7

Question 24

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

Answer 24

FACULTATIVE ANAEROBED – they generally ferment

non spore forming
gram negative rods

Question 25

do enterobacteriaceae contain oxidase? what about catalse?

Answer 25

no oxidase yes catalase

Question 26

true or false enterobacteriacea have cytochrome oxidase activity

Answer 26

FALSE -- they do not

Question 27

are enterbacteriaceae motile?

Answer 27

some are motile

Question 28

explain further how e. coli are classified

Answer 28

based on their surface antigens O polysaccharides are a subunit of LPS K antigens are capsule polysaccharides H proteins are flagellar proteins

Question 29

e. coli can adhere to many different cells. explain

Answer 29

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

Question 30

what is the COMMON toxin to all e. coli strains

Answer 30

endotoxin -- lipid A component of LPS

Question 31

are all e. coli encapsulated?

Answer 31

yes

Question 32

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

Answer 32

they ALL have a type 3 secretion system

Question 33

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

Answer 33

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

Question 34

true or false all e. coli strains have a common endotoxin

Answer 34

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

Question 35

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

Answer 35

SEPSIS ---- frequently cause bacteremia

Question 36

how can e. coli be transmitted

Answer 36

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

Question 37

what bacteria causes >80% of commonly acquired UTIs?

Answer 37

e. coli -- specifically UPEC (uropathogenic ecoli)

Question 38

what are the 3 extraintestinal diseases caused by e. coli

Answer 38

bacteremia neonatal meningitis UTI

Question 39

what makes UPEC very good at causing UTIs?

Answer 39

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

Question 40

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

Answer 40

cystitis (bladder infection) and pyelonephritis (kidney infection)

Question 41

E. coli are a major contributor to ____ illness

Answer 41

diarrheal

Question 42

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

Answer 42

watery diarrhea: ETEC, EPEC bloody diarrhea: EHEC EIEC watery AND bloody diarrhea: EAEC

Question 43

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

Answer 43

-opportunistic commensal activity -from contaminated food or water

Question 44

which e. coli strain causes "traveler's diarrhea"

Answer 44

enterotoxigenic e. coli (ETEC)

Question 45

what is the ETEC pilli

Answer 45

CF (colonizing factor)

Question 46

what are the ETEC toxins

Answer 46

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

Question 47

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

Answer 47

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)

Question 48

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?

Answer 48

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

Question 49

what is the pilli for EPEC

Answer 49

bundle-forming pilli (Bfp)

Question 50

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

Answer 50

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

Question 51

explain how EPEC causes A/E lesions

Answer 51

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

Question 52

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

Answer 52

EPEC (enteropathogenic e. coli)