Remaining Bacterial Agents causing Afebrile Diarrhea (not due to food)

Question 1

ETEC Characteristics

Answer 1

GNR, motile by flagella (H antigen) or non-motile, non-fastidious, facultative anaerobe, Oxidase (-), Coliform!

Question 2

ETEC is a coliform, meaning:

Answer 2

ferments lactose with acid and gas production

Question 3

ETEC on MacConkey agar will grow

Answer 3

PINK colonies

Question 4

What other organism is a coliform?

Answer 4

Aeromonas

Question 5

Salmonella, Shigella, Yersinia would all grow what color on MacConkey agar?

Answer 5

White!

Question 6

ETEC has what antigens

Answer 6

O, H, K, pili/fimbriae

Question 7

Risk factors for ETEC infection

Answer 7

Poor sanitation, contaminated water/food

Question 8

ETEC infections are commonly called

Answer 8

Traveler’s diarrhea, weanling diarrhea, montezuma’s revenge, etc

Question 9

Transmission of ETEC is

Answer 9

HIGH dose: fecal-oral (not p-to-p)

Question 10

Reservoir of ETEC is

Answer 10

human and animal GIT

Question 11

What allow ETEC to attach to small intestine?

Answer 11

Fimbriae/Colonization Factor Antigen (CFA)

Question 12

ETEC virulence factors?

Answer 12

CFA/fimbriae, LT toxin, and ST toxin

Question 13

ETEC LT toxin mechanism

Answer 13

heat-labile enterotoxin w/ same mechanism as Cholera toxin CT-1/2 (binds Gm1 ganglioside, blocks GTPase, activates A.C. and cAMP, hyper secretion of Cl-, HCO3-, H2O = diarrhea)

Question 14

ETEC CFA mechanism

Answer 14

fimbriae that allows ETEC to adhere to small bowel

Question 15

ETEC ST toxin mechanism

Answer 15

heat-stabile enterotoxin that binds guanylate cyclase, activates cGMP, Phosphorylates Cl- channel–> Cl- secretion and blocks Na+ absorption

Question 16

Immunity for ETEC is partially provided by?

Answer 16

O1 cholera vaccine

Question 17

ETEC inhabits the

Answer 17

small intestines

Question 18

Incubation period of ETEC

Answer 18

1-2 days

Question 19

Duration of illness from ETEC

Answer 19

1-3 days; self-limiting

Question 20

Main symptoms from ETEC infection

Answer 20

abrupt onset of mild-severe afebrile watery diarrhea

Question 21

Diagnosis is made from

Answer 21

History; lab results of little value

Question 22

Culture ETEC on what media?

Answer 22

Non-fastdious, ALSO a COLIFORM (lactose fermenter) –> PINK on MacConkey

Question 23

Treatment for ETEC infection

Answer 23

Replace fluids/electrolytes, pepto bismol

Question 24

Should you give abx for ETEC infection?

Answer 24

NO, unless severe case

Question 25

Prevention of ETEC

Answer 25

O1 Cholera vaccine has some cross-coverage, pepto-bismol, abx protection for traveler's

Question 26

EAEC is a subgroup of

Answer 26

ETEC

Question 27

EAEC has the ability to

Answer 27

adhere to epithelial cells such as Hep-2 in a "stacked-brick" pattern

Question 28

EAEC symptoms

Answer 28

PERSISTENT diarrhea (>14 days)

Question 29

Newer strains of EAEC can produce

Answer 29

Shiga toxins

Question 30

EAEC strains have adapted

Answer 30

from cattle GIT pathogens to HUMAN GIT pathogens

Question 31

Aeromonas hydrophila Characteristics

Answer 31

GNR, Mesophilic to psychrophilic (RT to cold temperatures), resistant to Cl-, Oxidase +, coliform

Question 32

Aeromonas hydrophila causes up to ___% of gastritis in the world

Answer 32

13

Question 33

Aeromonas hydrophila is also associated with what type of infections

Answer 33

cellulitis

Question 34

Aeromonas hydrophila is found primarily in

Answer 34

fresh-water sources

Question 35

Aeromonas hydrophila can be isolated from many environments due to

Answer 35

its ability to survive and proliferate in cold temperatures

Question 36

Main symptoms of Aeromonas hydrophila

Answer 36

afebrile, watery diarrhea

Question 37

Duration of symptoms of Aeromonas hydrophila

Answer 37

1-3 days

Question 38

Virulence factors of Aeromonas hydrophila

Answer 38

Enterotoxin (cholera/CT-like toxin)

Question 39

Transmission of Aeromonas hydrophila

Answer 39

fecal-oral (contaminated water/food source)

Question 40

Culture of Aeromonas hydrophila is normally on

Answer 40

Blood agar w/ ampicillin (MDR)

Question 41

Treatment of Aeromonas hydrophila

Answer 41

Rehydrate

Question 42

Should Aeromonas hydrophila be treated w/ abx?

Answer 42

No, it's usually MDR anyways

Question 43

Main risk factor of Aeromonas hydrophila

Answer 43

ingestion of fresh-water or brackish water contaminated food/water