Pathogensis Model

Question 1

What are the characteristics of Corynebacterium Diptheriae?

Answer 1

• gram positive
• club shaped rods
• non motile
• non sporing
• aerobic
• Strict pathogen (obligate parasite:typically causes disease when present)

Question 2

Where does Corynebactirum Diptheriae colonize on the body?

Answer 2

-nasopharynx/ skin

Question 3

What are the virulence factors of Corynebacterium Diptheriae?

Answer 3

• fimbraie (attachment)

- A-B exotoxin (binds to human cells, catalyst enzyme)

Question 4

Which organs/tissues can be damaged by Corynebacterium Diptheriae?

Answer 4

-throat, heart, kidney, brain

Question 5

What is fibro-fatty infiltration?

Answer 5

-when dead cells get replaced by scar tissue

Question 6

Explain what the A:B toxin is

Answer 6

• A-chain enzyme: stops eukaryotic translation(protein synthesis)=cell dies
• B-chain enzyme: binds heparin-binding epidermal growth factor found on many cells

Question 7

How is Corynebacterium Diptheriae prevented?

Answer 7

-use of vaccines; although, does not prevent carriage

Question 8

How do bacteriophages relate to Corynebacterium and Cutaneous Diptheriae?

Answer 8

-Bacteriophages can sometimes infect a bacterial cell, and then the DNA from the bacteriophage infects into the bacterial cells chromosomes

Question 9

What does Diptheria toxin (DTx) do when it enters its target cell?

Answer 9

-toxin genes are carried to bacteria by Beta-Phage, a virus (bacteriophage) which infects Corynebacterium.

Question 10

Diptheria Toxin attacks what organs?

Answer 10

• heart (cardiotoxicity, myocarditis)
• kidneys (nephrotoxicity)
• brain (neurotoxicity)

Question 11

How does the Diptheria vaccine work?

Answer 11

-the vaccine pre-educates the immune system, and equips the adaptive immune system to fight pathogens pre-infection

Question 12

What is the difference between the Diptheria vaccine vs antitoxin?

Answer 12

• vaccines stimulate antibody production (long term)

- antitoxins are pre made antibodies that neutralize toxins when injected (short term)

Question 13

What is the difference between Cutaneous Diptheriae vs Corynebacterium Diptheriae

Answer 13

• Cutaneous Diptheriae
  
  • wound/skin lesion infection
  • slow healing ulcer
  • toxin stays local, damage limited
• Corynebacterium Diptheriae
  
  • nasopharynx/ skin infection
  • transmitted through droplets, nasal secretion

Question 14

Why doesn’t the Diptheria vaccine prevent people from carrying. Corynebacterium diptheriae

Answer 14

-a toxoid isn’t directly injecting the antibodies, its stimulating antibody production

Question 15

A true/strict pathogen need to have what criteria? (2)

Answer 15

• be an obligate parasite: causes disease when present in/on human
• a specialist on humans

Question 16

What is a facultative parasite?

Answer 16

• life cycle does not have to damage host

- can switch to becoming a parasite when on/in a person

Question 17

What are commensalism opportunists (pathogen)?

Answer 17

-normal micro flora that have been displaced and now cause disease

Question 18

Where is staphylococcus epidermidis found?

Answer 18

• normally found on the surface of the skin

Question 19

Describe the structure of Staphylococcus epidermidis. What type of pathogen is this?

Answer 19

• Bacterial

- gram positive cocci

Question 20

What are 2 diseases caused by staph. epi.?

Answer 20

• furuncle (skin infection)

- infective endocarditis (destroys heart valves)

Question 21

Name 7 virulence factors of S. Epidermidis

Answer 21

• exopolymers (capsule, biofilm)
• adhesions (proteins attach)
• staphyloferrins ( iron siderophores)
• complement (c5) protease: digests immune system proteins called ‘complement’
• cytolosins:increase inflammation by stimulating neutrophils;also cause cell lysis
• antimicrobial protein (AMP) protease
• antibiotic resistant strains common

Question 22

What are the function of heart valves?

Answer 22

-provide a one way flow of blood so there wouldn’t be a back flow

Question 23

What is an endocardium? Endocarditis?

Answer 23

• Endocardium: the lining of the hollow parts of the heart, where the blood makes contact with the blood
• Endocarditis: when that lining becomes imflammed including the valves

Question 24

How is the overall pathogenicity of S. Epidermidis? What factors make it more likely to develop a serious infection?

Answer 24

-Very rare; Only becomes an infection under the right conditions

Weakened immune system

Question 25

Summarize the complement system of proteins

Answer 25

-is a system of plasma proteins that can be activated directly by pathogens or indirectly by pathogen-bound antibody, leading to a cascade of reactions that occurs on the surface of pathogens and generates active components with various effector functions

Question 26

What is an environmental opportunist? Name one example

Answer 26

-pathogens that have the ability to grow in the outside host environment and invade their host in favorable conditions Ex. Pseudomonas aeruginosa

Question 27

Where are 3 places you might come in contact with P. Aeruginosa?

Answer 27

- normally found in soil - drain of a sink - hot tub (inadequately treated with chlorine)

Question 28

Describe the structure of P. Aeruginosa. What kind of pathogen is it?

Answer 28

- bacterial pathogen - gram negative rod - has flagella - does not do photosynthesis

Question 29

What color does P. Aeruginosa appear when growing in a culture? What makes it turn this color?

Answer 29

- greenish color (not a photosynthesis pigment) | - the pigment increases inflammation, and is called pyocyanin (pho=pus, cyan=bluish color)

Question 30

Describe 2 ways that long, dense LPS chains affect the ability of P. Aeruginosa to cause disease

Answer 30

- good at establishing biofilm - can resist many disinfectants - resist attacks from the complement system

Question 31

List 5 virulence factors of P. Aeruginosa

Answer 31

- biofilm - pyocyanin pigment (increases inflammation_ - pillis/fimbriae (attachment) - neurominidase enzyme (enhances binding of fimbriae) - LPS (resist attacks from complement system)

Question 32

Name 6 anatomical locations where P. Aeruginosa commonly causes infections

Answer 32

- ear (swimmers ear; outer ear canal infection) - hair follicles (hot tub folliculitis) - skin (would and burn infections) - bladder (urinary tract infections) - lining of the heart (heart damage) - lungs (lung infection)

Question 33

What is zoonosis?

Answer 33

-a disease which can be transmitted to humans from animals | Ex. Rabies

Question 34

What is another name for a neuron? What is its function?

Answer 34

- nerve cells | - receive incoming signals and sends outgoing signals to target cells

Question 35

What is the name of the narrow gap found between neurons?

Answer 35

-synapse

Question 36

At which point of a rabies infection can the immune system possibly intercept the virus?

Answer 36

- the synapse before it reaches into the CNS, 10 day period | - treatment: post exposure prophylaxis

Question 37

What does the post exposure prophylaxis treatment consist of?

Answer 37

- Rabies vaccine (active immunization): stimulate patient to make their antibodies to bind rabies virions - rabies immunoglobulin (passive immunization): pre-formed antibodies that bind rabies virions

Question 38

Based on the lecture material, what is an example of a commensalism opportunist, zoonotic pathogen, strict/true pathogen, and a environmental opportunist?

Answer 38

- Commensal Opportunist: Staphylococcus epidermidis - zoonotic pathogen: rabies virus - strict/true pathogen: Corynebacterium diptheriae - environmental opportunist: Pseudomonas aeruginosa