Bailey Study Guide Bacterial Infection

Question 1

What are the six steps to the infectious disease process?

Answer 1

1. encounter
2. entry
3. colonization and/or invasion
4. multiplication and/or spread
5. damage
6. outcome

Question 2

Describe an encounter with an infectious agent.

Answer 2

Coming in contact with an infectious agent

*encounter DOES NOT ensure infection

Question 3

For an infection to take hold the step after encounter is known as ___, where bacteria find their way into the body.

Answer 3

entry

Question 4

Pathogens must first ___ a surface before causing disease.

Answer 4

colonize (adhere to host tissue)

Question 5

What are the different kinds of colonization?

Answer 5

1. nonspecific adherence
   - reversible adherence
   - docking
   ex) Brownian movement (random interactions), electrostatic attractions, interactions with glycocalyx or extraceullar matrices
2. Specific adherence: adherence involving adhesins
   - irreversible
   - anchoring

Question 6

Where are adhesions usually found and are the interactions between them usually specific or nonspecific?

Answer 6

• adhesions are often found on fimbrae (pili) but can be found in capsules or cell surface
• interactions are specific- adhesin receptors are specific for adhesins

Question 7

Why does S mutans (the cause of carries) bind to tooth pellicle?

Answer 7

the adhesin is Glucosyl transferase which binds to salivary protein that is involved in pellicle formation

Question 8

Some pathogens only ___, but most ___.

Answer 8

colonize

invade

Question 9

Entry into a host can be thought of as two different processes. Describe each.

Answer 9

1. ingress of microorganisms into body cavities that are contiguous with the outside (inhalation or ingestion)
2. penetration or microorganisms into deeper tissues after crossing an epithelial barrier (insect bites, cuts, organ transplants, blood transfusion)

Question 10

The nose, mouth, respiratory tract, alimentary canal, anus, female genital tract, and urinary tract are all in direct contact with the exterior and therefore are generally not considered inside the body.

Answer 10

just know that

Question 11

Penetration of bacteria into epithelial cells usually involves two steps: ___ to specific receptors followed by ___.

Answer 11

attachment

internalization

Question 12

How do bacteria take up nutrients?

Answer 12

1. carrier-mediated diffusion (facilitated)
   - concentration gradient
2. phosphorylation-linked transport (group translocation)
3. Active transport (energy dependent)

Question 13

To invade, pathogens must have specific virulence factors that allows them to invade the host. These are generally referred to as ___.

Answer 13

invasins

Question 14

Secreted ___ can facilitate invasions.

Answer 14

enzymes

Question 15

The ___ of microbes is important for disease progression and often occurs with multiplication

Answer 15

spread

Question 16

Describe the two mechanisms of spread.

Answer 16

1. lateral propagation to contiguous tissues (multiply then spread)
2. Dissemination to distant sites (spread then multiply)

Question 17

What are the different causes of damage due to infection?

Answer 17

• Host response: phagoctyes, cytotoxic T cell activity

- infectious organism: lytic viral infections, invasins damage host tissue, toxin producing microbes

Question 18

Disease symptoms are often dependent upon pathogen ___.

Answer 18

density

Question 19

What are the was damage can be caused to the infected organism?

Answer 19

• host response: phagocytes, cytotoxin T cell activity

- Infectious organism: lytic viral infections, invasins damage host tissue, toxin producing microbes

Question 20

What are the different types of toxins?

Answer 20

• endotoxins: component of cell wall (the term endotoxin generally reserved for lipopolysaccharide)
• Exotoxins: soluble substances secreted into host tissue
  
  • cytotoxins: lyse cells
    
    • hemolysis: lyse RBCs
    • leukocidins: lyse white blood cells
  • enterotoxins: affect intestinal cells
  • neurotoxins: affect neurons

Question 21

The ___ is the end result of an infection, wether it be no disease, disease, death, etc.

Answer 21

outcome

Question 22

___ size is important in establishing an infection (varies with different organisms)

Answer 22

inoculum

Question 23

What are the 4 possible outcomes of a host-parasite interaction?

Answer 23

1. the host wins and clears the infection
2. the parasite overcomes the host
3. the host and parasite adapt to each other
4. neither host or parasite win. this chronic infection can continue indefinitely

Question 24

Most microorganisms are ___. They coexist without causing harm

Answer 24

commensal

Question 25

What is a category of microbes that can grow with limited nutrients?

Answer 25

oligotrophs

Question 26

What type of microbe require some oxygen, but lower levels of oxygen.

Answer 26

microaerophiles

Question 27

What type of microbe grow well in mild temperatures (15-45 degrees C)

Answer 27

mesophiles

Question 28

Gram ___ bacteria hace a thick cell wall made up of murein (peptidoglycan).

Answer 28

positive

Question 29

___ is made up of long chains of N-acetylmuramic acid and N-acetylglucosmine linked together by short polypeptides

Answer 29

Murein

Question 30

Gram ___ bacteria have a thin layer of murein between two membranes (lipid bilayers)

Answer 30

negative

Question 31

The outside of the outer membrane of gram negative bacteria is made up of ____ that is different for different bacteria.

Answer 31

lipopolysaccharide (LPS)

Question 32

LPS is an ___ even in it purified form

Answer 32

endotoxin

Question 33

LPS is made up of a lipid region (fatty acids attached to a phosphorylated disaccharide) that faces into the membrane and a ___ region that faces out

Answer 33

polysaccharide

Question 34

The outer ___ region is highly variable and antigenic

Answer 34

O-antigen

Question 35

What are some extracellular structures pathogens can have?

Answer 35

1. pili (fimbrae) 2. flagella 3. glycocalyx

Question 36

___ are involved in the attachment of bacteria to cells and other surfaces

Answer 36

pili (fimbrae)

Question 37

___ are specialized proteins that are more specifically developed for adherence

Answer 37

adhesins (on tip of fimbrae)

Question 38

Bacteria can have one flagella, known as ___, a few known as ___, and a lot known as ___.

Answer 38

monotrichous, lophotrichous, peritrichous

Question 39

Flagella cause movement when they rotate ___, and tumbling when they rotate ___.

Answer 39

counterclockwise | clockwise

Question 40

When movement by bacteria is directed, it is referred to as ___.

Answer 40

taxis

Question 41

Taxis can be directed toward or away from a stimuli. Some examples of the different kinds of taxis are ___, ___, ___, and ___.

Answer 41

chemotaxis, aerotaxis, osmotaxis, thermotaxis

Question 42

___ is a substance that surrounds a cell.

Answer 42

glycocalyx

Question 43

Glycocalyx that is well organized, firmly attached is called ___.

Answer 43

capsule

Question 44

Capsules are usually made of ___, but can include ___ and ___.

Answer 44

polysaccharides, monosaccharides, and glycoproteins

Question 45

Glycocalyx that is not well organized or firmly attached is called a ___.

Answer 45

slime layer

Question 46

Why are capsules beneficial to pathogens?

Answer 46

For some bacteria, encapsulation is necessary for the virulence factor. ex) strep pneumoniae

Question 47

Can the immune system ever recognize a bacterium that has a capsule?

Answer 47

yes, troll like receptor 5 can recognize flagella and sometimes the capsular polysaccharide can be recognized