CH. 15 Methods of Pathogenicity

Question 1

What are the three portals of entry?

Answer 1

1. Mucus Membrane: open to outside.
2. Skin: 1st line of defense.
3. Parenteral Routs: bites, cuts, allow org. to live under the skin.

Question 2

Numbers of Pathogens
LD50:
ID50:

Answer 2

• lethal dose for 50% of hosts/ indicates virulence.

- dose needed to produce infection in 50% host / used to compare toxicity.

Question 3

How do Pathogens penetrate the host?

Answer 3

1. Capsules
2. Cell wall structure
3. Enzymes
4. Wax

Question 4

1. Capsules

Answer 4

• impairs phagocytosis
• antibodies against capsule
• s. pneumonie, klebsiella, pneuomoniae

Question 5

2. Cell Wall Structure

Answer 5

• M protein in some= attachment, protection to heat

- streptococcus pyogenes

Question 6

3. Enzymes

Answer 6

• leukocides
• hemolysins
• Coagulase - fibrinogen; allows a wall off (hide)
• Kinases - breaks down collagen fibers.
• Hyaluronidase: breaks down, hyouronic acid
• Collagenase- breaks down collagen

Question 7

4. Wax

Answer 7

• found in some cell walls
• resist digestion by some phagocytes
• Myobacterium tuberculosis can divide inside a white blood cell

Question 8

Direct Damage:

Answer 8

pathogen invades hosts cell

Question 9

Toxin Production
Toxingenicity:
Toxemia:
Exotoxins:

Answer 9

• ability to produce toxins
• found in blood

-produced during normal growth and metabolism.
(most lethal toxin known to humans : clostridium)

Question 10

Cytotoxins:

Neurotoxins:

Enterotoxins:

Antitoxins:

Answer 10

• kills host cells
• attack nervous system
• attack lining of digestive tract
• antibodies made against toxin not bacteria

Question 11

Diphtheria-

Erythrogenic Toxin-

Botulism Toxin-

Tetanus Toxin-

Staph Toxin-

Answer 11

• clostridium diphtheriae
• S. pyogenes
• C. botulinum
• C. tetani
• S aureus

Question 12

Pathogenic Properties of other Microbes

1. Viruses

Answer 12

-attachment sites mimic substances useful to the host cell
-Nuerotransmitters
-Cytocidal vs. non-cytocidal
kills host cells. does not kill host cells

Question 13

Pathogenic Properties of other Microbes

2. Fungi

Answer 13

• candida albicans produces protease

- ergot - toxin produced by a fungol plant pathogen ingest = causes hallucinations

Question 14

Aflotoxin:

Mycotoxin:

Answer 14

• grains, seeds, carcinogen

- in mushroom deadly

Question 15

Pathogenic Properties of other Microbes

3. Protozoan

Answer 15

-single cell, more complex than bacteria eukarya.

transmitted by vectors: sand flies, mosquitoes

Question 16

Pathogenic Properties of other Microbes

4. Helminthes

Answer 16

-small part of life cycle is microscopic

deprive host of nutrients; movement through digestive system