Bacterial Infections of GI II

Question 1

What stains red (positive) on MacConkey agar

Answer 1

E. coli

Question 2

What stains white (negative) on MacConkey agar

Answer 2

salmonella, shigella

Question 3

What stains red (positive) on Indole test

Answer 3

e. coli, vibrio spp.

Question 4

What stains the same (negative) on indole test

Answer 4

salmonella

Question 5

What is the Hydrogen Sulfite test, test between

Answer 5

salmonella and shigella

Question 6

What produces black precipicate on H2S test

Answer 6

salmonella

Question 7

What doesn’t produce a precip. on H2S test

Answer 7

shigella

Question 8

Characteristics of EPEC

Answer 8

gram neg
facilitative anaerobe
moderately invasive

Question 9

What does EPEC usually affect

Answer 9

kids - pediatric

Question 10

What is the main symptom of EPEC

Answer 10

watery diarrhea

Question 11

How does EPEC cause diarrhea

Answer 11

destroys microvilli by acing with BfpA, injects Tir, causes protein to it. F actin at the end of Tir causes loss of microvilli

Question 12

How can do you test for EPEC

Answer 12

ferments lactose (red on MacConkey agar)
indole positive
PCR

Question 13

How do you treat EPEC

Answer 13

supportive therapy

Question 14

Characteristics of ETEC

Answer 14

gram negative
facilitative anaerobe
non-invasive

Question 15

Who does ETEC usually affect

Answer 15

travelers

Question 16

What does ETEC cause

Answer 16

watery diarrhea

Question 17

How does ETEC cause diarrhea

Answer 17

attaches to fimbriae

releases LT and ST toxins

Question 18

LT toxin

Answer 18

AB toxin

increases cAMP

Question 19

ST toxin

Answer 19

non-AB toxin

increases cGMP

Question 20

How do you diagnosis ETEC

Answer 20

history

DNA probes to detect LT and ST encoding genes

Question 21

How do you treat ETEC

Answer 21

supportive therapy

Question 22

Characteristics of Salmonella Typhi

Answer 22

gram neg
facilitative anaerobe
motile rods, flagellates H antigen
acid tolerant

Question 23

Who is the reservoir of salmonella typhi

Answer 23

humans

Question 24

How is Salmonella typhi transmitted

Answer 24

fecal-oral

Question 25

What are the symptoms of salmonella typhi

Answer 25

fever with headache fever increased over 3 days typhoid fever for ~4 weeks GI symptoms

Question 26

How does Salmonella Typhi causes disease

Answer 26

adhers to M-cells and enterocytes. Uses T3SS to get into the cell. ruffles take it into the cell, macrophage takes it to the lymph nodes where it escapes

Question 27

How do you diagnose Salmonella Typhi

Answer 27

culture stool and blood

Question 28

How do you treat salmonella typhi

Answer 28

fluoroquiolones, trimethoprim-sulfamethoxazole, or broad spectrium cephlosporin

Question 29

How do you prevent Salmonella Typhi

Answer 29

Avoid water in countries that are full of it | Vax

Question 30

What is the Salmonella typhi vax

Answer 30

Ty21A, ViCPS

Question 31

Characteristics of Nontyphoidal Salmonella

Answer 31

gram neg, facultative anaerobe motile rods, flagellated H antigen acid tolerant same as S. typhi but not as human adapted

Question 32

What are the reservoirs of nontyphoidal salmonella

Answer 32

many animal reservoirs - often in reptiles

Question 33

How does nontyphoidal salmonella get transmitted

Answer 33

``` contaminated food (eggs) human to human transmission is unlikely ```

Question 34

What are the symptoms of nontyphoidal salmonella

Answer 34

nausea, vomiting, cramps, watery diarrhea can have bloody stool or not 50% have fever resolves in about a week

Question 35

Pathogenesis of Nontyphoidal salmonella

Answer 35

starts the same as s. typhi | either kills the macrophage or uses the macrophage to get to other parts of the body

Question 36

How do you diagnosis nontyphoidal salmonella

Answer 36

detect anti-Vi antigen antibodies non-lactose fermenting produces H2S

Question 37

How do you treat salmonella gastroenteritis

Answer 37

electrolyte replacement | NO antibiotics!!!

Question 38

How do you treat salmonella systemic infection

Answer 38

antibiotics

Question 39

Is there a vax for nontyphoidal salmonella

Answer 39

no

Question 40

Characteristics of campylobacter jejuni

Answer 40

gram negative rod - sea-gull shaped | microaerophilic

Question 41

Resevoirs of campylobacter jejuni

Answer 41

many animals -turkeys, pets

Question 42

Diseases of campylobacter jejuni

Answer 42

ulceration and acute enteritis sepsis sequelae

Question 43

Guillain-Barre Syndrome

Answer 43

acute immune-mediated polyneuropathy

Question 44

What are the symptoms of Guillain-Barre syndrome

Answer 44

progressive, symmetric muscle weakness, accompanied by absent or depressed deep tendon reflexes

Question 45

How do you treat campylobacter jejuni

Answer 45

supportive | antibiotic (macrolides)

Question 46

How do you diagnosis campylobacter jejuni

Answer 46

culture (look for microaerophilic environment growth)