Infection (Bailey)

Question 1

What is the most common reason people seek treatment for infectious disease?

Answer 1

Oral infections

Question 2

What are the six steps in the infectious disease process?

Answer 2

1. Encounter
2. Entry
3. Colonization and/or invasion
4. Multiplication and/or spread
5. Damage
6. Outcome

Question 3

Does encountering an infectious microbe always result in infection?

Answer 3

No.

Some diseases are grown from within

Question 4

Although the oral cavity and alimentary canal are inside the body, what is special about this canal?

Answer 4

It is connected to the outside world on both ends

Question 5

What are the two major ways a pathogen will adhere to a host tissue?

Answer 5

1. Nonspecific adherence: reversible docking

2. Specific adherence: irreversible anchoring with adhesins

Question 6

Why does streptococcus mutans bind to the tooth pellicle?

Answer 6

It has an adhesin that specifically binds to tooth pellicle (specific adherence)

Question 7

What is needed for a pathogen to colonize?

Answer 7

Must be able to live in the environment it wants to colonize

Question 8

What are three ways bacteria take up nutrients?

Answer 8

1. Carrier-mediated diffusion
2. Phosphorylation-linked transport
3. Active transport

Question 9

What allows a pathogen to invade after colonization?

Answer 9

Specific virulence factors that allow for invasions

Question 10

What are the two major mechanisms for disease multiplication?

Answer 10

1. Lateral propagation to contiguous tissues (multiply -> spread)
2. Dissemination to distant sites (spread -> multiply)

Question 11

What are two major types of toxins during infection?

Answer 11

1. Endotoxins: component of cell wall

2. Soluble substances secreted into host tissues

Question 12

What makes a microbe a pathogen?

Answer 12

1. Adheres
2. Colonizes
3. Replicates in given niche
4. Causes damage

Question 13

T/F: No microorganism is intrinsically benign or pathogenic

Answer 13

TRUE

Question 14

T/F: Obligate anaerobes are bacteria that must have oxygen to grow.

Answer 14

FALSE.

Obligate anaerobes: cannot tolerate oxygen

Strict aerobes: must have oxygen to grow

Question 15

Which bacteria can grow with or without oxygen?

Answer 15

Facultative anaerobes

Question 16

What is unique about oligotrophs?

Answer 16

Can grow with limited nutrients

Question 17

What is unique about microaerophiles?

Answer 17

Require some oxygen, but not a lot

Question 18

What is unique about mesophiles?

Answer 18

Grow well in mild temperature

Question 19

T/F: Gram-positive bacteria have a much thicker cell wall than gram-negative.

Answer 19

TRUE

Question 20

What differs in the structure of the cell wall between gram-positive and gram-negative bacteria?

Answer 20

Murein in gram-negative contains DAP

Question 21

Which type of bacteria has techoic acid at the surface?

Answer 21

Gram-positive

Question 22

What is the importance of the techoic acid and lipopolysaccharide?

Answer 22

They are considered PAMPs that the immune system can recognize

Question 23

What pattern recognition receptor recognizes LPS?

Answer 23

Toll-like receptor 4

Question 24

T/F: Toll-like receptors 2 and 6 recognize teichoic acids together.

Answer 24

TRUE

Question 25

What is the function of fimbriae (or Pili)?

Answer 25

Involved in attachment to other surfaces. Contain adhesins

Question 26

What are the two processes by which a pathogen can enter a host?

Answer 26

1. Through body opening (mouth, nose, etc.) | 2. By piercing epithelia (insect bites, cuts, etc.)

Question 27

What are the two steps of penetration into epithelial cells?

Answer 27

1. Attachment | 2. Internalization

Question 28

________ size is very important in establishing an infection.

Answer 28

Inoculum

Question 29

What are the possible outcomes of a host-parasite infection?

Answer 29

1. Host clears out infection 2. Parasite overcomes host 3. Host and parasite adapt to each other 4. Chronic infection - no one wins

Question 30

Which has more Murien (peptidoglycan): gram positive or gram negative?

Answer 30

Gram positive

Question 31

Which type of bacteria has an outer membrane made up of LPS?

Answer 31

Gram-negative

Question 32

What makes up LPS?

Answer 32

A lipid region that faces the membrane and a polysaccharide that faces out

Question 33

What part of the LPS is highly variable and antigenic?

Answer 33

Outer region (O-antigen)

Question 34

T/F: LPS is an endotoxin.

Answer 34

TRUE

Question 35

What are sex pili?

Answer 35

Connect cells during DNA transfer

Question 36

What happens when a flagella rotates clockwise? Counterclockwise?

Answer 36

Clockwise: Tumbling Counterclockwise: Movement

Question 37

What type of movement is used by bacteria for chemotaxis?

Answer 37

Flagellar movement

Question 38

What is special about obligate intercellular parasites?

Answer 38

Can only grow inside host cells

Question 39

What four things must an infectious agent do to survive?

Answer 39

1. Avoid being washed away 2. Find a niche with proper nutrition 3. Survive host defense 4. Transfer to new host

Question 40

What are some ways that an infection can damage a host?

Answer 40

1. Cell death 2. Alter metabolism 3. Mechanical causes 4. Host response 5. Toxins

Question 41

What are the structures on bacterial surface recognized by the body?

Answer 41

PAMPs

Question 42

What are some common antigens recognized by pattern receptor proteins?

Answer 42

LPS - O antigen, Receptor 4 Flagella - H antigen Capsule - K antigen