Bacterial Path and Host Defense Mechs

Question 1

What the three mechanisms of disease for bacteria?

Answer 1

Toxicity, Host Immune Response, and Colonation and Proliferation.

Question 2

What is LPS and where is it found?

Answer 2

LPS is an endotoxin and found on gram (-) bacteria.

Question 3

Name some virulence factors found in salmonella.

Answer 3

• Toxins (enterotoxin, endotoxin, and cytotoxin).
• Iron-chelating siderophores.
• Cell surface polysaccharide O antigen, flagellar H antigen, and fimbriae all enhance adherence.
• Capsular Vi polysaccharide inhibits complement binding and antibody-mediated killing.
• Salmonella contains at least two pathogenicity islands known as Salmonella pathogenicity island 1 and 2 (SPI1 and SPI2). Responsible for invasion, systemic disease, and host-immune evasion.
• Salmonella plasmids contain drug resistance genes.

Question 4

What does O antigen do?

Answer 4

Inhibits phagocytic killing of bacteria.

Question 5

Name the three types organisms that have Hemolysins and an example of each.

Answer 5

Alpha: Will damage but not kill RBC, strep-virdans (mouth)
Beta: Completely destroys RBC, strep-pyrogenase
Gamma: No hemolysin, staph-epidermis

Question 6

With AB toxins, the B portion binds to a receptor protein while the A portion shuts down protein synthesis in the cell. (T/F)

Answer 6

T

Question 7

How does the botulinum toxin affect muscle?

Answer 7

It blocks the release of Acetylcholine and therefore muscles can’t contract.

Question 8

How does the tetanus toxin affect muscle?

Answer 8

It binds to inhibitory interneurons and prevents the release of glycine, thus, preventing the relaxation of muscle.

Question 9

What causes random T Cells and MHC molecules to bind incorrectly, thus increasing inflammation?

Answer 9

Superantigens (an exotoxin)

Question 10

What is the difference between type 2 and type 3 hypersensitivity?

Answer 10

Type 2: Ab are made, but also binds to self