Chp 15 Part II

Question 1

What is virulence?

Answer 1

The tendency of a pathogen to cause damage/disease to the host.

Question 2

What makes one bacterium more virulent than another?

Answer 2

The presence or absence of virulence factors.

Question 3

Give an example of a highly virulent bacterium.

Answer 3

Staphylococcus aureus.

Question 4

What are virulence factors?

Answer 4

Any pathogenic attribute that promotes colonization, immunoevasion, or obtaining nutrition from the host.

Question 5

What are examples of virulence factors?

Answer 5

Adhesion factors, exoenzymes, toxins, and antiphagocytic factors.

Question 6

What is adhesion in microbial pathogenesis?

Answer 6

The process by which microorganisms attach themselves to cells.

Question 7

Why is adhesion important?

Answer 7

It is required to establish colonies successfully within the host.

Question 8

What are adhesion factors?

Answer 8

Specialized structures like ligands that bind to host cell receptors.

Question 9

What happens if a microorganism cannot make adhesins?

Answer 9

It becomes avirulent and cannot establish infection.

Question 10

What are exoenzymes?

Answer 10

Extracellular enzymes released by pathogens to break down host structures and evade defenses.

Question 11

Give two examples of exoenzymes.

Answer 11

Hyaluronidase and collagenase.

Question 12

What does hyaluronidase do?

Answer 12

Digests hyaluronan, the ‘glue’ that holds animal cells together.

Question 13

What does collagenase do?

Answer 13

Breaks down collagen, a major structural protein in the body.

Question 14

What are bacterial toxins?

Answer 14

Chemicals that harm tissues or trigger immune responses that cause damage.

Question 15

What is toxemia?

Answer 15

The presence of toxins in the bloodstream.

Question 16

What are the two types of bacterial toxins?

Answer 16

Exotoxins and endotoxins.

Question 17

What is an exotoxin?

Answer 17

A toxin secreted by bacteria that can cause severe damage.

Question 18

What are the three types of exotoxins?

Answer 18

Cytotoxins, neurotoxins, and enterotoxins.

Question 19

What is the function of cytotoxins?

Answer 19

They kill host cells or affect their function.

Question 20

What do neurotoxins target?

Answer 20

They specifically interfere with nerve cell function.

Question 21

What do enterotoxins affect?

Answer 21

They affect cells lining the gastrointestinal tract.

Question 22

What is an A-B toxin?

Answer 22

A type of exotoxin where the A component is active and the B component binds to the host cell.

Question 23

Give an example of an A-B toxin.

Answer 23

Botulinum toxin produced by Clostridium botulinum.

Question 24

How does botulinum toxin affect the body?

Answer 24

It prevents muscle contraction, causing flaccid paralysis.

Question 25

What are endotoxins composed of?

Answer 25

Lipopolysaccharides (LPS) from the outer membrane of Gram-negative bacteria.

Question 26

What is the toxic component of endotoxin?

Answer 26

Lipid A.

Question 27

What symptoms can endotoxins cause?

Answer 27

Fever, inflammation, diarrhea, hemorrhaging, shock, and blood coagulation.

Question 28

How are endotoxins released?

Answer 28

When Gram-negative bacteria die and their cell walls break apart.

Question 29

What is the pyrogenic response?

Answer 29

A fever-inducing mechanism triggered by endotoxins.

Question 30

What are antiphagocytic factors?

Answer 30

Factors that prevent phagocytosis by host immune cells.

Question 31

Why do some bacteria have capsules?

Answer 31

Capsules help bacteria evade immune cells by making them hard to recognize or engulf.

Question 32

What is antigenic variation?

Answer 32

A mechanism where pathogens alter their surface proteins to evade the immune system.

Question 33

Which bacterium uses antigenic variation through homologous recombination?

Answer 33

Neisseria gonorrhoeae.

Question 34

What is bacterial gastroenteritis?

Answer 34

Inflammation of the stomach or intestines caused by bacteria, often due to contaminated food or water.

Question 35

What is the primary transmission route for bacterial gastroenteritis?

Answer 35

Fecal-oral route.

Question 36

Which bacterium causes cholera?

Answer 36

Vibrio cholerae.

Question 37

What is the main virulence factor of Vibrio cholerae?

Answer 37

Cholera toxin, an A-B toxin.

Question 38

What are 'rice-water stools'?

Answer 38

Watery diarrhea characteristic of cholera infection.

Question 39

How does cholera toxin affect the body?

Answer 39

It activates chloride channels, leading to rapid water loss and dehydration.

Question 40

What is STEC?

Answer 40

Shiga toxin-producing E. coli.

Question 41

What are symptoms of STEC infection?

Answer 41

Diarrhea, severe cramping, and sometimes hemolytic uremic syndrome (HUS).

Question 42

What is HUS?

Answer 42

A condition where damaged red blood cells build up in the kidneys, potentially leading to kidney failure. Also a potential symptoms of STEC.

Question 43

How is STEC transmitted?

Answer 43

Mostly through contaminated food, especially undercooked beef.

Question 44

What is Clostridium difficile (C. diff) infection associated with?

Answer 44

Antibiotic use, which disrupts normal gut microbiota.

Question 45

What are symptoms of C. diff infection?

Answer 45

Watery diarrhea, colitis, and in severe cases, pseudomembranous colitis.

Question 46

What are the two main toxins of C. diff?

Answer 46

Toxin A (causes fluid loss) and Toxin B (kills colon cells).

Question 47

Why is C. diff difficult to control in hospitals?

Answer 47

It forms endospores, allowing it to survive harsh conditions.

Question 48

How can bacterial gastroenteritis be prevented?

Answer 48

Proper food handling, sanitation, and clean water sources.

Question 49

What is septicemia?

Answer 49

A severe bloodstream infection where bacteria multiply in the blood, leading to shock.

Question 50

Types of virulence factors

Answer 50

Endotoxin, exotoxin, antiphagocytosis, antigenosis, exoenzymes