Lecture 3 Part 3: Corynebacterium, Listeria & Bacillus

Question 1

What are the two types of spore-forming Gram-positive rods?

Answer 1

Aerobes – Bacillus anthracis
Anaerobes – Clostridium difficile

Question 2

Which Gram-positive rod is an aerobic spore-former?

Answer 2

Bacillus anthracis

Question 3

Which Gram-positive rod is an anaerobic spore-former?

Answer 3

Clostridium difficile

Question 4

What are the two types of non-spore-forming Gram-positive rods?

Answer 4

Uniform shape – Listeria
Coryneform (irregular) shape – Corynebacterium

Question 5

Which non-spore-forming Gram-positive rod has a uniform shape?

Answer 5

Listeria

Question 6

Which non-spore-forming Gram-positive rod has an irregular (Coryneform) shape?

Answer 6

Corynebacterium

Question 7

What is the Gram reaction and catalase activity of Corynebacterium diphtheriae?

Answer 7

Gram-positive (+)
Catalase-positive (+)

Question 8

Is Corynebacterium diphtheriae aerobic or anaerobic?

Answer 8

Aerobic

Question 9

What is the shape of Corynebacterium diphtheriae?

Answer 9

club shaped rods

Question 10

Does Corynebacterium diphtheriae form spores?

Answer 10

it is Non-spore forming

Question 11

What metabolic byproduct does Corynebacterium diphtheriae produce?

Answer 11

lactic acid

Question 12

Where is Corynebacterium diphtheriae commonly found in humans?

Answer 12

on skin and nasal mucosa

Question 13

What is the only known reservoir for Corynebacterium diphtheriae?

Answer 13

humans

Question 14

true or false
Corynebacterium diphtheriae primarily causes disease in adults.

Answer 14

FALSE

It is primarily a pediatric disease

Question 15

What is the major virulence factor of Corynebacterium diphtheriae?

Answer 15

Diphtheria toxin

Question 16

What type of toxin is the diphtheria toxin?

Answer 16

exotoxin

Question 17

What is the function of the B subunit of diphtheria toxin?

Answer 17

Binds to epidermal growth factor receptor (EGFR)

Question 18

What does the A subunit of diphtheria toxin do?

Answer 18

Inactivates elongation factor-2 (EF-2), blocking protein synthesis

Question 19

What is the sudden onset disease caused by Corynebacterium diphtheriae that affects the respiratory system?

Answer 19

Respiratory Diphtheria

Question 20

What is the primary site of colonization for Corynebacterium diphtheriae in respiratory diphtheria?

Answer 20

Pharyngeal epithelium (pharyngitis)

Question 21

What does the diphtheria toxin do in respiratory diphtheria?

Answer 21

Mediates tissue damage and causes the formation of a thick exudate (pseudomembrane)

Question 22

What is the pseudomembrane in respiratory diphtheria made of?

Answer 22

White blood cells (WBCs), fibrin, and debris

Question 23

What serious complication can the pseudomembrane in respiratory diphtheria cause?

Answer 23

Obstructs the airway, leading to respiratory obstruction

Question 24

What is a common symptom of respiratory diphtheria due to the dislodging of epithelial cells?

Answer 24

severe coughing

Question 25

What cardiovascular complication can occur in severe respiratory diphtheria?

Answer 25

acute myocarditis

Question 26

How does cutaneous diphtheria present clinically?

Answer 26

It involves the invasion of subcutaneous tissue, resulting in the development of pustules and ulcers.

Question 27

What type of bacteria is Listeria monocytogenes?

Answer 27

Gram-positive rods

Question 28

Is Listeria monocytogenes an obligate aerobe or facultative anaerobe?

Answer 28

Facultative anaerobe

Question 29

What kind of pathogen is Listeria monocytogenes?

Answer 29

intrcelluar pathogen

Question 30

Does Listeria monocytogenes form spores?

Answer 30

it is non-spore forming

Question 31

What hemolytic pattern does Listeria monocytogenes show?

Answer 31

Weakly β-hemolytic

Question 32

How does Listeria monocytogenes typically appear under the microscope?

Answer 32

Often in pairs and motile at temperatures below 37°C

Question 33

What unique growth properties does Listeria monocytogenes have?

Answer 33

It can grow at 4°C, across a wide pH range, and in high salt concentrations

Question 34

How is Listeria monocytogenes primarily transmitted?

Answer 34

Transmitted by exposure to contaminated food

Question 35

How does Listeria monocytogenes adhere to host cells?

Answer 35

adhere to host cell via internalins binding E-cadherin

Question 36

How is Listeria monocytogenes transported into host cells?

Answer 36

It is transported into enterocytes or M cells.

Question 37

What does Listeria monocytogenes use to burst phagolysosomes?

Answer 37

It uses a pore-forming cytolysin called listeriolysin O (LLO).

Question 38

true or false Listeria monocytogenes can survive in macrophages after lysis of phagolysosomes.

Answer 38

true

Question 39

What is the result of Listeria monocytogenes infection in host cells?

Answer 39

Invasion, phagolysosome lysis, bacterial replication, and reinfection

Question 40

What is a common clinical disease caused by Listeria monocytogenes in neonates?

Answer 40

Neonatal disease can include amnionitis, stillbirth, meningitis, and meningoencephalitis.

Question 41

What are the symptoms of Listeria monocytogenes infection in adults?

Answer 41

Influenza-like illness with possible gastroenteritis.

Question 42

What is a severe complication of Listeria monocytogenes infection in adults?

Answer 42

Bacteremia

Question 43

What type of bacteria is Bacillus anthracis?

Answer 43

Gram(+) rods, aerobic or facultative.

Question 44

Is Bacillus anthracis motile?

Answer 44

it is non-motile

Question 45

true or false Bacillus anthracis can survive for decades in spore form

Answer 45

true

Question 46

What is the function of the polypeptide capsule of Bacillus anthracis?

Answer 46

it evades phagocytosis

Question 46

Is Bacillus anthracis non-hemolytic?

Answer 46

yes

Question 47

What is a characteristic appearance of Bacillus anthracis colonies?

Answer 47

They form a "Medusa head" pattern

Question 48

What type of toxin does Bacillus anthracis produce?

Answer 48

Produces potent exotoxin complex

Question 49

How is Bacillus anthracis transmitted?

Answer 49

Transmitted through contact with infected animals & animal products

Question 50

Why is Bacillus anthracis a bioterrorism threat?

Answer 50

Because it can cause pulmonary anthrax

Question 51

Name the 4 virulence factors for bacillus anthracis

Answer 51

1. Edema factor (EF) 2. Lethal factor (LF) 3. Protective antigen (PA) – binds receptor 4. glutamic acid capsule

Question 52

What is the function of the protective antigen (PA) in Bacillus anthracis?

Answer 52

binds to host receptor

Question 53

What does the edema factor (EF) and lethal factor (LF) do in Bacillus anthracis?

Answer 53

They increase adenylate cyclase activity and inactivate host protein production.

Question 54

What is the capsule of Bacillus anthracis made of?

Answer 54

A glutamic acid capsule that helps it evade phagocytosis

Question 55

TRUE OR FASLE Bacillus anthracis causes hemorrhagic pneumonia.

Answer 55

TRUE

Question 56

true or false Skin lesions caused by Bacillus anthracis are known as malignant pustules.

Answer 56

TRUE

Question 57

true or false Bacillus anthracis can lead to meningitis.

Answer 57

TRUE