Enterobacterales (Exam 3)

Question 1

The order Enterobacteriacae is made up of (gram-positive/gram-negative) (rods/cocci/spirochetes).

Answer 1

gram-negative rods

Question 2

Enterobacteriacae are oxidase (negative/positive).

Answer 2

negative

Question 3

What is the classification of Enterobacteriacae in terms of what oxygen conditions they grow best?

Answer 3

facultative anaerobe

Question 4

All species within Enterobacteriacae ferment _______ while only some ferment _______.

Answer 4

glucose
lactose

Question 5

Where is the normal location for Enterobacterales?

Answer 5

GI tract

Question 6

Enterobacterales typically have (systemic/local) effects.

Answer 6

systemic

Question 7

What is the route of transmission for Enterobacteriaceae?

Answer 7

fecal-oral contamination

Question 8

What two ways do Enterobacteriaceae have antibiotic resistance?

Answer 8

1. ESBL (extended-spectrum beta-lactamases)
2. R-factor plasmids

Question 9

Of the family Enterobacteriaceae, what four genera are commonly isolated from diseases in vet med?

Answer 9

1. Escherichia
2. Klebsiella
3. Salmonella
4. Proteus

Question 10

What diagnostic test is used for Enterobacteriacae?

Answer 10

triple sugar iron agar (TSI)

Question 11

_______ agar is selective against gram positive bacteria, and therefore used to help identify Enterobacteriacae.

Answer 11

macconkey

Question 12

Which agar is selective for Salmonella? Which two allow enrichment for Salmonella (growth advantage)?

Answer 12

brilliant green

selenite broth
tetrathionate broth

Question 13

IMViC tests separate _______ from other fecal source bacteria in water analysis based on metabolic products.

Answer 13

Escherichia coli

Question 14

What 4 tests does a IMViC include?

Answer 14

1. indole
2. methyl red
3. voges-proskauer
4. citrate

Question 15

List the 4 varying surface antigens of Enterobacteriaceae family.

Answer 15

O, H, K, F

Question 16

The variations of O, H, K, and F surface antigens on Enterobacteriaceae determine different ________.

Answer 16

serotypes

Question 17

Match each surface antigen to its description:

1. flagella
2. capsule
3. fimbria/pili
4. region 1 of LPS

Answer 17

1. H
2. K
3. F
4. O

Question 18

(T/F) Enterobacteriaceae usually do not cause disease.

Answer 18

True

Question 19

What kind of diseases are most commonly caused by Enterobacteriaceae?

Answer 19

GI disease

Question 20

Clinical signs are very similar between genus and species of Enterobacteriaceae unless _______ are present.

Answer 20

exotoxins

Question 21

What two methods are used to help diagnose Enterobacteriaceae?

Answer 21

1. TSI agar
2. oxidase test

Question 22

(T/F) Bacteria of the family Enterobacteriaceae have highly reactive LPS/endotoxin which causes similar disease manifestations.

Answer 22

True

Question 23

(T/F) There is high variation in surface structures leading to “variants” of Enterobacteriaceae.

Answer 23

True

Question 24

Which species of Enterobacteriaceae is pathogenic and a significant animal and human health concern due to widespread outbreaks?

Answer 24

Escherichia coli

Question 25

What 3 species of Enterobacteriaceae are present with fecal contamination of water?

Answer 25

Escherichia Enterobacter Klebsiella

Question 26

All _______ of E. coli worsen infection.

Answer 26

exotoxin / enterotoxin

Question 27

What are the 2 types of exotoxins of E. coli?

Answer 27

1. enterotoxins 2. shiga toxins

Question 28

_______ are secreted by live bacteria into the cell directly or into the circulation.

Answer 28

exotoxins

Question 29

What do endotoxins, secreted after bacteria die, induce?

Answer 29

systemic inflammatory effect

Question 30

Which exotoxin of E. coli is cytotoxic, and therefore, has concern for endothelial damage?

Answer 30

shiga toxin

Question 31

Regarding enterotoxins of E. coli, there are two types: _____ toxin is small peptide which is non-immunogenic while _______ toxin is an AB type protein than is immunogenic.

Answer 31

stable labile

Question 32

Grossly, what do shiga toxins cause?

Answer 32

bloody diarrhea

Question 33

Enterotoxins cause hypersecretion of ________ and _______ in the small intestine.

Answer 33

water electrolytes

Question 34

Heat-labile enterotoxins activate ________ which generates ______, causing hypersecretion in the small intestine.

Answer 34

adenylyl cyclase cAMP

Question 35

Heat-stabile enterotoxins have two units, STa which activates _______ and hypersecretion, and STb which causes ion imbalance, ________ production, and disruption of barrier function leading to hypersecretion.

Answer 35

guanylyl cyclase prostaglandins

Question 36

What do the following tests look for? Ligated gut loop test Infant mouse test Y-1 mouse adrenal cell test PCR

Answer 36

production of enterotoxin

Question 37

(T/F) Shiga toxin is an AB toxin and the A domain is the active form.

Answer 37

True

Question 38

What does STEC stand for?

Answer 38

shiga toxin producing E. coli