GI Gram - Bacteria

Question 1

GI and extra-intestinal tract gram - rods

Answer 1

escherichia coli
salmonella (enteritidis, typhi, typhimurium)
yersinia (enterocolitica, pseudotuberculosis)
campylobacter (fetus, jejuni)

Question 2

Primary GI gram - rods

Answer 2

shigella sonnei
helicobacter pylori
vibrio (cholerae, parahaemolyticus)

Question 3

extra-intestinal gram - rods

Answer 3

enterobacter
klebsiells (oxytoca, pneumoniae)
serratia marcesens
proteus

Question 4

enterobacteriacae primary pathogens

Answer 4

shigella
salmonella
yersinia
(e. coli)
(klebsiella pneumonia)

Question 5

enterobacteriacae opportunistic pathogens

Answer 5

proteus
serratia
enterobacter
providencia
morganella
(e. coli)
(klebsiella pneumonia)

Question 6

production of H2S (fxn - high levels)

Answer 6

prevents mitochonddrial cytochrome enzymes –> stops cellular respiration

Question 7

production of H2S (fxn - low levels)

Answer 7

used as a signaling molecule in SM relaxation and memory formation

Question 8

EMB agar growth characteristics

Answer 8

(eosine methylene blue)
no gram + growth
lactose fermentation –> purple or metallic green

Question 9

MacConkey agar growth characteristics

Answer 9

no gram + growth

lactose fermentation –> pink-purple

Question 10

XLD agar growth characteristics

Answer 10

xylose lysine deoxycholate
phenol red = pH indicator
xylose fermentation lowers pH (red –> yellow)

Question 11

XLD w/ salmonella

Answer 11

yellow colonies (xylose ferm)
then red again w/ black centers

Question 12

XLD w/ shigella

Answer 12

red colonies (no xylose ferm)

Question 13

XLD w/ E. coli

Answer 13

yellow colonies, turn med yellow

Question 14

Antigens (VFs)

Answer 14

O antigen (LPS)
H antigen (flagella)
K antigen (capsule)

Question 15

endotoxins

Answer 15

LPS

Question 16

alpha-hemolysin

Answer 16

pore forming

cause cytoplasmic leakage and cell death

Question 17

cytotoxic necrotizing factor

Answer 17

A B toxins disrupts G protein signaling

increases cAMP levels

Question 18

LT

Answer 18

heat labile toxin
ribosylates G protein
up cAMP

Question 19

ST

Answer 19

heat stable toxin

targets guanylate cyclase

Question 20

shiga toxin

Answer 20

released by cellular death

A B toxin - B binds to receptor, A crosses golgi to inactivate ribosome

Question 21

pili types

Answer 21

type 1
P pili
CFA (colonization forming antigen)
BFP (bundle forming pili)

Question 22

type 1 pili

Answer 22

D-mannose; epithelial cells

Question 23

P pili

Answer 23

digalactoside

uroepithelial and RBCs in P blood group

Question 24

gram -‘s that cause secretory diarrhea

Answer 24

enterotoxigenic E. coli

V. cholera

Question 25

gram -‘s that cause inflammatory diarrhea

Answer 25

enteroinvasive E. coli
shigella
salmonella

Question 26

gram -‘s that invade lymph nodes

Answer 26

salmonella typhi
yersinia enterocolitica
campylobacter jejuni

Question 27

gram - invasion of lymph nodes Sx

Answer 27

fever, headache, WBC elevation

lymph node enlargement, bacteremia, sepsis

Question 28

dysentery

Answer 28

inflammatory response in colon
blood and pus in stool
inflammation caused by cytotoxins (shiga)

Question 29

enteric fever

Answer 29

systemic disease that starts in intestine

then invade lymphoid + reticuloendothelial system

Question 30

enterotoxigenic E. coli ST/LT mech

Answer 30

ST –> up cGMP
LT –> up cAMP
–> active secretion of ions/water

Question 31

enterotoxigenic E. coli syndrome

Answer 31

traveler’s diarrhea

rice water diarrhea

Question 32

enterotoxigenic E. coli effect on intestinal mucosa

Answer 32

prevent Na and Cl reabsorption

stim Cl and HCO3 secretion

Question 33

enteropathiogenic E. coli syndrome

Answer 33

watery diarrhea, mostly in inffants

Question 34

enteropathiogenic E. coli VFs

Answer 34

BFP

shiga-like toxins

Question 35

enteropathiogenic E. coli transmission

Answer 35

in utero or at birth

Question 36

enterotoxigenic E. coli transmission

Answer 36

eat food/water contaminated w/ human waste

person-to-person

Question 37

enterohemorrhagic E. coli syndrome

Answer 37

bloody diarrhea
hemorrhagic colitis
hemolytic uremic syndrome

Question 38

enterohemorrhagic E. coli transmission

Answer 38

may have cattle reservoir

hamburger meat

Question 39

enterohemorrhagic E. coli mech

Answer 39

shiga-like toxin binds to 60S ribosome –> intestinal epi cell death

Question 40

hemolytic uremic syndrome Sx

Answer 40

hemolytic anemia
acute renal failure
low platelet count

Question 41

hemolytic uremic syndrome mech

Answer 41

shiga-like toxin damage endothelial cells of glomerulus

Question 42

enteroinvasive E. coli

Answer 42

shigella-like ddysentery w/ fever and bloody stools

may not ferment lactose

Question 43

enteroadherent E. coli

Answer 43

causes traveler’s diarrhea and persistent diarrhea in infants

Question 44

extra-intestinal E. coli infections

Answer 44

usually caused by own flora

ex: UTIs, neonatal meningitis, nosocomial infections, sepsism pneumonia

Question 45

salmonella characteristics

Answer 45

motile
no lactose ferm
makes H2S
grow on Hektoen agar

Question 46

salmonella VFs

Answer 46

Vi antigen

Question 47

salmonella mech

Answer 47

1. salmonella enters intestinal 2. cells by endocytosis
2. go through to submucosa
3. get taken up by macs and carried to reticuloendothelial system
4. multiply intracellularly –> lymphoid hyperplasia/hypertrophy
5. reenter bowel by liver/gallbladder

Question 48

salmonella typhi causes

Answer 48

enteric (typhoid) fever

Question 49

shigella mech

Answer 49

1. enter cells by endocytosis
2. escape vesicles and multiply in cells (no macs)
3. invade neighboring cells
4. cells die - cause abscess, bloody diarrhea
5. WBC inflamm

Question 50

vibrio cholera mech

Answer 50

1. cholera toxin bind to receptor
2. A subunit enters cell - activates adenylate cyclase
3. cAMP up
4. massive ions/water secretion