Host parasite relationships

Question 1

What is the term microbiota?

Answer 1

Normal flora basically

Question 2

What is medical microiology?

Answer 2

Study of dyamins interaction between microbes and the human host

Question 3

What is a symbiosis?

Answer 3

Close and prolonged association between 2 or more organisms of different species

Question 4

What is commensalis?

Answer 4

Host gets no benefits to symbiosis, but is not harmed either

Question 5

What is mutualism?

Answer 5

Both host and microorganisms benefit

Question 6

What is parasitism?

Answer 6

Microorganisms benefits, but the host is harmed

Question 7

What is a niche?

Answer 7

A shelter/physical space in the body that provides nutrients

Question 8

What is the normal microbiota?

Answer 8

Commensal or mutual symbionts that are adapted to specific niches

Question 9

True or false: the normal microbiota tend to avoid directly injuring the host?

Answer 9

True

Question 10

What are bacteriosins?

Answer 10

Toxins that bacteria produce that are toxic only to other bacteria

Question 11

What type of microrganisms in the lungs?

Answer 11

None, usually considered sterile

Question 12

How much bacteria do the stomach and the esophagus have?

Answer 12

Very little

Question 13

Why do PPIs change the microbiota?

Answer 13

Change the pH, change the bacteria

Question 14

True or false: fetueses are generally sterile?

Answer 14

True

Question 15

Where do the bacteria come from just after birth?

Answer 15

Either from the vagina, or from the environment

Question 16

True or false: The urinary bladder is generally considered sterile

Answer 16

True for boards, but not really

Question 17

Why does the normal microbiota change as we grow?

Answer 17

Developing immunity, then decreasing

Question 18

What are resident vs transient members of the microbiota?

Answer 18

Resident- long term occupation of niches

Transient = opposite

Question 19

Why are some bacteria transient members?

Answer 19

Competition from resident bacteria

Immune system target

Chemical changes in the body

Question 20

Where does staphloccous epidermidiis live? Gram positive or negative? Cocci or baccili?

Answer 20

Skin, nose, ears

Gram +, cocci

Question 21

What are group A streptococcus pyogenes?Gram positive or negative? Cocci or baccili?

Answer 21

Gram + cocci in chaines that colonize the oropharynx of children

Causative agent of strep throat

Question 22

What are pathogens?

Answer 22

Microorganisms that have the ability to cause disease

Question 23

What are strict pathogens?

Answer 23

Organisms that are always associated with disease

Question 24

What are opportunistic pathogens?

Answer 24

normal micobiota that take advantage of preexisiting

Question 25

Are most infectious disesaes caused by opportunistic infections or by strict pathoges?

Answer 25

Opportunistic infections

Question 26

What is pathogenicity?

Answer 26

The ability of a microorganisms to cause disease

Question 27

What is virulence?

Answer 27

A measurement of pathogenicity

Question 28

What are virulence factors?

Answer 28

Factors produced by organisms that enable it to infect, cause disease, and/or kill a host

Question 29

UIs are generally caused by what bacteria?

Answer 29

E.coli

Question 30

What is the causative agaent of pseudomembrane colitis? Cause?

Answer 30

C. diff, (normal microbiota) Abx use kills microbiota

Question 31

What is the cause of OM? (3)

Answer 31

Strep pneumonia, haemophilus influenza, and moraxella catarrhalis

Question 32

Why do children develop OM?

Answer 32

Tensor veli palatini muscle is not develop, and cannot close the eustaian tube

Question 33

What is a carrier?

Answer 33

An asmptomatic individual but has the ability to transmit the pathogens to others

Question 34

Can you be a permanent carrier of disease?

Answer 34

Yes

Question 35

What is a zoonotic entry into a human?

Answer 35

Animal to human

Question 36

What is a vector?

Answer 36

Like an asymptomatic carrier

Question 37

What are the commensal barriers to entry into a host?

Answer 37

niche bacteria killing off bad bacteria through competition

Question 38

What is the first step that a pathogen does in order to infect?

Answer 38

Adhesion through adhesins or attachment proteins on pilli

Question 39

Why do pathogenic bacteria only infect a certain area of the body?

Answer 39

Specific adhesion molecules only in certain areas in the body

Question 40

What is plaktincally?

Answer 40

Free moving in solution. Most bacteria are not free--they are stationary

Question 41

What are biofilms?

Answer 41

Bacteria encased in an exopolmeric substance of their own making

Question 42

What is the source of dental caries?

Answer 42

Biofilm that turns to acid

Question 43

How do biofilms protect bacteria from abx?

Answer 43

Slows the diffusion of abx, increased genetic exchange

Question 44

True of false: biofilms play a small role in infections?

Answer 44

False

Question 45

What are the sites that are considered sterile in the human body? (4)

Answer 45

Internal organs Upper urogenital tract Lungs Circulatory system

Question 46

What are the three factors that prevent transient bacteria from becoming resident members?

Answer 46

1. Immune responses 2. Competition from bacteria 3. Chemical changes

Question 47

What is the causative agent of strep throat? Is this a normal member of the microbiota?

Answer 47

Streptococcus Pyogenes

Question 48

What determines the tropism of a bacteria?

Answer 48

The specific adhesion molecules it has

Question 49

True or false: The majority of bacteria in nature do not live planktonically (i.e. freely moving or swimming

Answer 49

True

Question 50

What are the factors that bacteria in a biofilm have that prevents them from being affected by abx? (3)

Answer 50

1. Lower metabolism 2. Increase in genetic exchange 3. Slow diffusion of chemicals through the biofilm

Question 51

What are intracellular pathogens?

Answer 51

Bacteria that replicate inside a host cell

Question 52

What are the ways in which bacteria are toxic to a host?

Answer 52

1. Release toxins | 2. Byproducts of growth

Question 53

What are exotoxins?

Answer 53

are bacterial proteins that directly harm tissue or lead to destructive biological activities

Question 54

What is the AB binding toxin family?

Answer 54

An AB toxin is comprised of an A subunit that possesses the toxic activity and a B subunit that is responsible for binding to a host cell recepto

Question 55

What are endotoxins? What type of bacteria posses these?

Answer 55

Toxins on the outer surface leaflet of gram-negative bacteria

Question 56

What is the effect of a capsule on the bacteria's ability to evade the host immune system?

Answer 56

Increases it since the polysaccharide makes a poor antigen

Question 57

What is antigenic mimicry?

Answer 57

When bacteria produce/coat themselves in compounds that the host immune system recognizes as self

Question 58

Where are staph aureus bacteria usually found on the human body?

Answer 58

Nose, skin

Question 59

Where are staph aureus epidermisusually found on the human body?

Answer 59

Nose, skin,

Question 60

Where are diptheroids bacteria usually found on the human body?

Answer 60

Nose, urethra and vagina, skin,

Question 61

Where are streptococci bacteria usually found?

Answer 61

nose, mouth, throat, skin, urethra and vagina

Question 62

Where are strep mutans bacteria usually found on the human body?

Answer 62

teeth

Question 63

Where are strep viridan, pyogenes, and pneuumoniae bacteria usually found on the human body?

Answer 63

Throat

Question 64

Where are neisseria bacteria usually found on the human body?

Answer 64

Throat

Question 65

Where are haemophilus influenzae bacteria usually found on the human body?

Answer 65

Throat

Question 66

Where are pseudomonas aeruginosa bacteria usually found on the human body?

Answer 66

skin

Question 67

Where are Torulopsis bacteria usually found on the human body?

Answer 67

skin

Question 68

Where are Pityrosporum bacteria usually found on the human body?

Answer 68

skin

Question 69

Where are candida usually found on the human body?

Answer 69

mouth, skin,

Question 70

What are the bacteria that are found in the staomach?

Answer 70

Lactobacilli

Question 71

What are the bacteria that are found in the duodenum, jejunum, and ileum? (4)

Answer 71

Lactobacilli Streptococci Enterobacteria Baceroides

Question 72

What are the bacteria that are found in the large bowel? (10)

Answer 72

``` Strep E.coli bacteroides fusobacterium lactobacillus clostridium Staph auerues enterobacteria pseudomonas Salmonella ```

Question 73

Infections with staph epidermis are associated with what?

Answer 73

Prosthetic devices and IV catheters

Question 74

What are the opportunistic infections that are associated with IV catheters?

Answer 74

``` Staph epidermis Staph aureus (MRSA) ```

Question 75

What are the opportunistic infections associated with wound/surgical site infections?

Answer 75

Staph auerus Klebsiella pneumoniae Pseudomonas aeruginosa

Question 76

What are the opportunistic infections associated with bacterial endocarditits?

Answer 76

Strep viridans

Question 77

What are the opportunisitic infections associate with aspiration pneumonia?

Answer 77

Polymicrobial

Question 78

What types of bacteria are responsible for OM? (3)

Answer 78

Step penumoniae Haemophilus influenza Moraxella catarrhalis

Question 79

True or false: bacteria only produce pathology at the sites of infection

Answer 79

False- can produce toxins that disseminate

Question 80

How can bacteria evade IgA antibodies?

Answer 80

Secreting proteases

Question 81

How can bacteria resist complement?

Answer 81

By preventing complement from directly interacting with the membrane (capsule, long O-antigen on LPS) or through degradation of complement components.

Question 82

What is the MOA of diptheria toxin?

Answer 82

AB protein binds to cell surface, and inhibits EF-2

Question 83

What is the MOA of cholera?

Answer 83

AB binding protein increases adenylate cyclase activity by biding the G proteins and preventing inactivation of the cAMP producing protein

Question 84

What is the MOA of C. tetani?

Answer 84

Produce tetanospasmin that inhibits inhibitory transmitter release (tense paralysis)

Question 85

What is the MOA of c. botulinum?

Answer 85

Release toxin that blocks the release of ACH (flacid paralysis)

Question 86

What are superantigens?

Answer 86

Proteins that bind to MHC class II without requiring an antigen, and provoke an anaphylactic response

Question 87

What is antigenic variation?

Answer 87

Bacteria that quickly change their antigenic makeup, due to many recombination of silent and active genes

Question 88

What is quorum sensing?

Answer 88

A way for bacteria to sense the size of their population by secreting chemicals at appropriate times

Question 89

What are the ways that bacteria can escape phagocytic clearance?

Answer 89

``` Inhibit opsonization Inhibit chemotaxis Kill phagocyte Inhibit lysosomal fusion Escape lysosome Resistant antibacterial lysosomal action ```