Lower GI Bacteria Review

Question 1

Reactive arthritis is possible complication of

Answer 1

Salmonella enterica

Question 2

Distinguishing molecular features of salmonella vs shigella

Answer 2

salmonella is H2S positive and has flagella

salmon swim AND stink like sulfur

Question 3

Which bugs can cause HUS?

Answer 3

Shigella (Shiga toxin)

EHEC (STEC) E. coli (Shiga-like toxin)

Question 4

How do shiga toxin and shiga-like toxin work

Answer 4

inactivates 60S ribosome
Shigella: intracellular, invasive
EHEC: extracellular –> toxin pushed into cell
BOTH cause HUS (hemolytic uremic syndrome)

Question 5

ETEC vs EHEC (STEC)

Answer 5

ETEC: traveller’s diarrhea, cAMP –> CFTR activation, ie watery diarrhea

EHEC: dysentery, necrosis and inflammation from toxin

Question 6

HUS (hemolytic uremic syndrome)
cause
effect

Answer 6

HUS

cause: cytokine release from Shiga toxin from Shigella or Shiga-like toxin from EHEC
effect: anemia, thrombocytopenia, acute renal failure (microthrombi in kidney)

Question 7

EHEC diarrhea

Answer 7

bloody, shiga-like toxin

Question 8

Shigella diarrhea

Answer 8

bloody, shiga-toxin

Question 9

Salmonella enterica diarrhea

Answer 9

sometimes bloody

Question 10

Salmonella typhi diarrhea

Answer 10

constipation followed by diarrhea

very high fever

Question 11

Clostordium perfringes

transmission

Answer 11

SPORES!!

Question 12

Clostridium perfringes most commonly found here

due to:

Answer 12

cafeterias

due to ability of spores to grow bacteria while all warm and cozy

Question 13

Clostridium perfringes morphology

Answer 13

Gram +, bacilli, spore-forming

Question 14

Campylobacter jejuni morphology

Answer 14

Gram -, bacilli/spirilli (S- or comma-shaped)

Question 15

Gullian-Barré is complication of

Answer 15

campylobacter jejuni

Question 16

Listeria morphology

Answer 16

Gram +
bacilli
non-fastidious

Question 17

What genus causes cholerae?

Answer 17

Vibrio

Question 18

Vibrio morphology

Answer 18

Gram -
vibrio (curved rod)
facultative anaerobes
flagellates, mobile
oxidase + (Kovács oxidase reagent --> purple)
Vibrio spp

Question 19

How to identify vibrio ssp

Answer 19

Kovács reagent (turns purple)

b/c vibrio is oxidase +

Question 20

Vibrio cholerae

how it causes cholera

Answer 20

permanently activates Gs, increase cAMP, rice water diarrhea

Question 21

Vibrio parahaemolyticus

toxin

Answer 21

enterotoxin-mediated

pores formed in RBCs and epithelial cells

Question 22

Vibrio parahaemolyticus

Sx

Answer 22

mild bloody diarrhea
N/V
fever

Question 23

2 Vibrio species

Answer 23

cholerae

parahaemolyticus

Question 24

Bacillus cereus

carrier

Answer 24

rice

Question 25

Bacillus cereus

2 manifestations and pathologies

Answer 25

emetic: pre-formed cereulide toxin, perfs membranes
diarrhea: not pre-formed toxin, fluid secretion in small intestine

Question 26

Bacillus cerus

spores or not?

Answer 26

spore-forming

Question 27

3 forms of boulisum

Answer 27

infantile: ingesting spores in honey
foodborne: ingesting toxin in food
wound: toxin generation in wound

Question 28

C. bontulinum toxin

mechanism

Answer 28

blocks ACh release at motor end plate

–> flaccid paralysis (floppy baby syndrome)