GI Acute Non-Inflammatory Bacteria

Question 1

E. coli are (G-ve/G+ve) and facultative anaerobes

Answer 1

E. coli are G-ve and facultative anaerobes

Question 2

E. coli are G-ve and (aerobes/facultative anaerobes)

Answer 2

E. coli are G-ve and facultative anaerobes

Question 3

____ is the primary cause of “Traveller’s diarrhea”

Answer 3

Enterotoxigenic E. coli (ETEC)​ is the primary cause of “Traveller’s diarrhea”

Question 4

Enterotoxigenic E. coli (ETEC) is transmitted via ___ and ____

Answer 4

ETEC is transmitted via contaminated food and water

Question 5

describe the pathogenesis of Enterotoxigenic E. coli (ETEC)

Answer 5

Question 6

ETEC reach the ___ and colonize by using ____

Answer 6

ETEC reach the SI and colonize by using CFA (colonization factor antigens - fimbriae)

Question 7

once ETEC colonizes the SI wall, it produces ____

Answer 7

once ETEC colonizes the SI wall, it produces 2 plasmid-encoded enterotoxins (LT and ST)

Question 8

LT activates ___

while

ST activates ____

explain how this causes diarrhea

Answer 8

LT (heat labile) activates adenylate cyclase

while

ST (heat stable) activates guanylate cyclase

Question 9

Enteropathogenic E. coli (EPEC) can lead to ____ and is significant in ____

Answer 9

Enteropathogenic E. coli (EPEC) can lead to infantile diarrhea (childhood diarrhea) and is significant in developing countries

Question 10

describe the steps of pathogenesis in EPEC

Answer 10

1. ingestion of pathogen
2. colonization of SI
   
   • plasmid-borne enteric adherence factor (EAF) bundle-forming pilus (BFP)
3. effacement of microvilli
4. osmotic imbalance → watery diarrhea

Question 11

EPEC possess ____/____ which leads to the effacement of ____

Answer 11

EPEC possess plasmid-borne enteric adherence factor (EAF)/bundle-forming pilus (BFP) which leads to the effacement of microvilli

Question 12

the management of EPEC is with ____

Answer 12

the management of EPEC is with rehydration therapy

Question 13

describe the family Vibrionaceae

Answer 13

• single curved G-ve rods
• motile (single polar flagellum)
• non-spore forming
• oxidase +ve

Question 14

describe the Sketchy

Answer 14

Question 15

Vibrio cholerae ferments ___ and ___ but not ____

is ___ sensitive

and ___tolerant

Answer 15

Vibrio cholerae ferments sucrose and mannose but not arabinose

is acid sensitive

and halotolerant

Question 16

describe the pathogenesis of V. cholerae

Answer 16

1. ingestion
   
   • liquid = higher infective dose required
   • solid = lower infective dose bc food helps buffer low pH of stomach (since V. cholerae is acid-sensitive)
2. colonization of SI
3. production of cholera toxin
   
   1. bacteriophage-encoded AB toxin
4. action similar to LT toxin of ETEC
5. loss of H2O, Na, K, Cl, HCO3
6. profuse watery diarrhea

Question 17

V. cholerae produces ___ which is ___ encoded ____

Answer 17

V. cholerae produces cholera toxin which is bacteriophage encoded AB toxin

Question 18

the action of cholera toxin is similar to ___ of ____

Answer 18

the action of cholera toxin is similar to LT of ETEC

Question 19

describe the pathophysiological effects of V. cholerae

Answer 19

• dehydration: isotonic fluid loss
• hypokalemia: K+ ion loss
• metabolic acidosis: HCO3- loss

Question 20

describe the management of cholera

Answer 20

• management:
  
  • replace ionic loss
    
    • oral and/or IV admin. of glucose

Question 21

____ and ____ are involved in the prevention of cholera

Answer 21

sanitation and hygiene are involved in the prevention of cholera

Question 22

describe the diagnosis and identification of cholera

Answer 22

Question 23

describe the Sketchy

Answer 23

Question 24

name the 2 different diseases caused by C. perfringens

Answer 24

• necrotic enteritis
  
  • C. perfringens strain type C
• type A food-borne infxn (food poisoning)
  
  • • C. perfringens strain type A

Question 25

describe the pathogenesis of C. perfringens

Answer 25

Question 26

C. perfringens cytotoxic activity causes ____ in the membrane

Answer 26

C. perfringens cytotoxic activity causes pore formation in the membrane

Question 27

describe the symptoms of C. perfringens

Answer 27

watery diarrhea & severe abdominal pain

NO fever, nausea, vomiting

Question 28

describe Bacillus cereus

Answer 28

• G+ve rods
• arranged in chains
• aerobic or facultative
• spore-former
• emetic toxin & enterotoxin

Question 29

compared to C. perfringens, ____ is quicker and ___ is shorter for B. cereus foodborne illness

Answer 29

compared to C. perfringens, onset time is quicker and duration is shorter for B. cereus foodborne illness

Question 30

describe the pathogensis of B. cereus

Answer 30

1. ingestion of pathogen
2. colonization of SI and production of LT enterotoxin
3. acts on adenyl acyclase-cAMP