Lecture 15 - Microbial Mechanisms of Pathogenicity

Question 1

Describe the difference and relationship between INFECTION and DISEASE

Answer 1

Infection occurs when a pathogen gains access to a part of the body where it shouldn’t be or in abnormally high numbers and can cause disease once the pathogen causes cellular damage

Question 2

What is the most important determinant of a disease outcome?

Answer 2

the host’s immune system

Question 3

pathogenicity

Answer 3

the ability of a microbe to cause disease

Question 4

virulence

Answer 4

the relative degree of pathogenicity

(the relative degree of the ability of a microbe to cause disease)

Question 5

Name the 4 Main Steps that Must Occur for a Pathogen to Cause Disease

Answer 5

1 - Pathogen must gain access to the host through a portal of entry
2 - Pathogen must be able to adhere/stick to the body
3 - Pathogen must be able to penetrate and evade host’s immune defenses
4 - Pathogen must damage the host’s tissues

Question 6

Name 3 Portals of Entry Specific to Women

Answer 6

• Mammary Glands
• Vagina
• Placenta

Question 7

List Common Portals of Entry

Answer 7

• eyes
• ears
• mouth
• nose
• broken skin
• urethra
• anus

Question 8

mucous membranes

Answer 8

membranes lining body cavities that have an opening to the outside

(i.e. entire GI tract, urinary tract, bronchi)

Question 9

Parental Route of Entry

Answer 9

when a break in the skin becomes a portal of entry for a microbe

(i.e. dog bite, insect bite, cut/scrape, contaminated needle)

Question 10

Lethal Dose

Answer 10

the number of microbes it would take to kill half of the exposed population

Question 11

Infective Dose

Answer 11

The dose that will cause disease in 50% of the population

Question 12

ID

Answer 12

Infective Dose

Question 13

LD

Answer 13

Lethal Dose

Question 14

adhesin

Answer 14

found on the surface of bacterial cell walls which helps them adhere to the host’s membranes

• this aids the bacteria in resisting the normal flow of body fluids so that it can cause an infection

Question 15

Can staphylococcus aureus form a capsule?

Answer 15

Yes

Question 16

phagocytosis

Answer 16

cell eating

Question 17

Name 2 Components of a Cell Wall that are Anti-Phagocytic

Answer 17

• LPS (Lipopolysaccharide)
• Mycolic Acid

Question 18

LPS

Answer 18

Lipopolysaccharide

Question 19

Where is LPS (Lipopolysaccharide) Found?

Answer 19

the cell walls of Gram-Negative bacteria

Question 20

Name a Genus of Bacteria that Produces Mycolic Acid

Answer 20

Mycoplasma

Question 21

coagulase

Answer 21

an enzyme produced by some bacteria causing blood to clot

Question 22

fibrinolysin

Answer 22

an enzyme secreted by some bacteria to break down clots

Question 23

streptokinase

Answer 23

a type of fibrinolysin

Question 24

hyaluronidase

Answer 24

an enzyme secreted by some bacteria to break down hyaluronic acid in the body

Question 25

collagenase

Answer 25

an enzyme secreted by some bacteria to break down collagen

Question 26

IgA protease

Answer 26

an enzyme secreted by some bacteria to destroy IgA antibodies

Question 27

antigen

Answer 27

foreign substance that induces an immune response

Question 28

antigenic variation

Answer 28

occurs when an antigen mutates in such a way that the body cannot readily recognize it and initate an effective immune response rapidly

Question 29

How is it that viruses mutate so well?

Answer 29

RNA viruses are replicated by RNA Polymerase which is fairly error-prone. When RNA Polymerase makes a mistake it can change the RNA in such a way that it may code for different spike proteins

Question 30

Is COVID an RNA or DNA Virus?

Answer 30

RNA

Question 31

Membrane Ruffling

Answer 31

A method in which bacteria can pass into a huaman cell.

Question 32

siderophore

Answer 32

Molelcule secreted by bacteria that attach to Iron (Fe). The bacteria then reabsorb the siderophore attached to the Fe.

Question 33

LPS contains which endotoxin?

Answer 33

Lipid A

Question 34

Name two categories of Microbial Toxins

Answer 34

Endotoxins & Exotoxins

Question 35

Where are the genes for most exotoxins found?

Answer 35

Plasmids or Prophages

Question 36

Toxin Produced by Streptococcus pyogenes

Answer 36

Erythrogenic Toxin

Question 37

Toxin Produced by Clostridium botulinum

Answer 37

Botulinum Toxin

Question 38

Toxin Produced by Clostridium Tetani

Answer 38

Tetanus Toxin AKA Tetanospasmin

Question 39

Neurotoxins

Answer 39

exotoxins that attack nerve cells

Question 40

Enterotoxins

Answer 40

exotoxins that attack the intestines

Question 41

Leukocidin

Answer 41

an exotoxin which attacks and kills WBCs by disrupting the cell membrane

Question 42

-cide

Answer 42

to kill/destroy

Question 43

leuk/o

Answer 43

white

Question 44

WBC

Answer 44

White Blood Cells

Question 45

Hemolysin

Answer 45

an exotoxin which destroys RBCs

Question 46

RBC

Answer 46

Red Blood Cells

Question 47

hemo-

Answer 47

blood

Question 48

Gram-Negative Bacteria Stains

Answer 48

Pink

Question 49

Gram-Positive Bacteria Stains

Answer 49

Purple

Question 50

Is Clostridium geneus Gram-Positive or Negative?

Answer 50

Gram-Positive

Question 51

Do Gram-Negatives have endotoxin in their cell walls?

Answer 51

Yes - Lipid A

Question 52

pyrogen

Answer 52

fever-causing

Question 53

Are Endotoxins pyrogens?

Answer 53

Yes

Question 54

Are Exotoxins pyrogens?

Answer 54

Not necessarily

Question 55

Idiopathic Miscarriages may be associated with _____.

Answer 55

Endotoxins

Question 56

DIC

Answer 56

Disseminated Intravasular Coagulation

Question 57

What is DIC (Disseminated Intravascular Coagulation)?

Answer 57

tissue death caused by endotoxins causing numerous little blood clots which block off capillaries and consequently cause tissue death

Question 58

Hypersensitivity Reactions

Answer 58

immune responses that are more damaging than good (i.e. autoimmune reactions, transplant rejections, severe allergies)

Question 59

describe the tell-telll symptoms of shingles

Answer 59

rash or blistery-sores generally presenting only on one half of the body

Question 60

List a Few Pathogenic Properties of Fungi

Answer 60

- capsules - production of toxins - induction of hypersensitivity reactions

Question 61

Which portal of exit on a person is most common?

Answer 61

Respiratory (i.e. coughing and sneezing)