Lecture 7

Question 1

Normal Flora:

Answer 1

endogenous microorganisms that live on another living

organism without causing disease

Question 2

Pathogen:

Answer 2

an organism that can cause disease

Question 3

Opportunistic pathogen

Answer 3

are usually non-pathogenic organisms that
cause serious disease in immuno-compromised individuals or when in
other locations

Question 4

Virulence Factors

Answer 4

are bacterial features that contribute to infection

Question 5

Pathogenesis -

Answer 5

is the mechanism by which infections lead to symptoms

Question 6

Microbiome

Answer 6

microorganisms and their genes

Question 7

Microbiota

Answer 7

refers to the microbes

themselves

Question 8

How does normal flora prevent colonization of pathogens

Answer 8

competing with them
for essential nutrients and attachment
sites

Question 9

What normal flora can be found on the skin

Answer 9

Staphylococcus

Question 10

What normal flora can be found in the stomach

Answer 10

E.coli

Question 11

dysbiosis

Answer 11

When the body has altered microbiota

Question 12

Give an example of dysbiosis

Answer 12

Clostridium difficile infection

Question 13

How does clostridium difficile cause infection

Answer 13

• it contains endospores that can survive the acidity of the stomach
• It flourishes in the colon
• Toxins A and B cause mucosal damage

Question 14

Primary infection:

Answer 14

Initial infection with an

organism in the host. E.g., “Strep” throat

Question 15

Reinfection:

Answer 15

Subsequent infection by the

same organism in the host (after recovery)

Question 16

Secondary infection:

Answer 16

An infection that follows
on from, or is the indirect result of another
infection

Question 17

Superinfection:

Answer 17

Secondary infection that
occurs during treatment of a primary
infection

Question 18

what are examples of virulence factors

Answer 18

• adhesion
• invasion
• competition
• resistance
• secretion factors

Question 19

What structures mediate the

attachment of bacteria to mucosal or other surfaces

Answer 19

Pilli or fimbriae

Question 20

What structure mediates motility of bacteria

Answer 20

Flagella

Question 21

True or false shigella is amphitrichous

Answer 21

False , it does not have any flagella

Question 22

The difference between Monotrichous and Lopotrichous

Answer 22

• Mono means 1 flagella

- Lopo means more than one

Question 23

Slime Layer

Answer 23

not well organized

Question 24

Capsule

Answer 24

well organized

Question 25

How does a capsule or slime layer help an organism

Answer 25

Helps it resist environmental insults

Question 26

when are bacterial endospores formed

Answer 26

Formed during harsh environmental growth conditions

Question 27

why are bacterial endospores highly resistant to desiccation, chemicals, hot/cold temps

Answer 27

Dipicolinic acid

Question 28

which two Gram-positive genera form spores:

Answer 28

* Bacillus | * Clostridium

Question 29

Bacterial Biofilm

Answer 29

``` Slimy extracellular matrix produced by the bacteria • Biofilm composed of extracellular polymeric substances (EPSs) ```

Question 30

Type 3 Secretion System T3SS

Answer 30

acts as a “needle” to inject effector proteins into host and modifying host cellular characteristics -found in gram negative bacteria

Question 31

Hyaluronidase

Answer 31

a bacterial enzyme which breaks down the connective tissue component

Question 32

Hemolysins

Answer 32

a bacterial enzyme which break down a variety of | host cells, including red blood cells

Question 33

Exotoxins

Answer 33

Toxins produced by bacteria that are secreted into | the environment

Question 34

A/B-type Toxin(exotoxin)

Answer 34

: A “active” subunit and B “binding” subunit

Question 35

B-subunit

Answer 35

binds to specific host cell receptor, leading to internalization

Question 36

A-subunit

Answer 36

disassociates from B-subunit in host cell and targets cellular function

Question 37

Membrane disrupting toxin(exotoxin)

Answer 37

* Cytotoxin secreted by bacteria from local infection * Toxin acts by forming pores in host cell membrane * Cytotoxin causes localized inflammation and damage

Question 38

Super-Antigen (exotoxin)

Answer 38

Non-specific activation of T cells leads to massive cytokine | release, causing Toxic Shock

Question 39

• Enterotoxins

Answer 39

found in the intestinal mucosa (e.g., | in the pathogenesis of Vibrio cholera)

Question 40

• Neurotoxins:

Answer 40

which occur in nerve tissues where they cause neurological damages (e.g., in the pathogenicity of Clostridium tetani)

Question 41

• Cytotoxins

Answer 41

are normally found in the general tissues of the body where they cause a series of local and systemic damages

Question 42

Lytic Cycle

Answer 42

DNA replication of virus takes place independently from the host DNA replication

Question 43

Lysogenic Cycle

Answer 43

DNA replication of the virus takes place along with the host DNA replication

Question 44

Endotoxins

Answer 44

microbial toxins which are produced only on cell lysis (cell death) -can cause sepsis

Question 45

How do endotoxins produce their effect

Answer 45

activating the | complement system by the alternative pathway

Question 46

Describe the multi disease process

Answer 46

- incubation period (no symptoms) - prodromal period - illness - decline - convalescence