export_hostparasite relationships

Question 1

Symbiosis

Answer 1

Prolonged association between two different species

Question 2

Commensalism

Answer 2

One organism benefits, the other is not affected

Question 3

Niche

Answer 3

Shelter where nutrients are provided

Question 4

Normal microbiota

Answer 4

“Flora”
Commensal or mutual symbionts
Compete with pathogenic microorganisms

Question 5

What part of our body is generally considered to be sterile?

Answer 5

Lungs (all tissue below the trachea)

Question 6

What part of your body is the microbiota variable, and why?

Answer 6

Skin

Can change based on what you touch

Question 7

Fetal microbiota

Answer 7

Generally sterile

Question 8

Neonate microbiota

Answer 8

Colonized during birth (vaginally)

Rapidly after delivery (C-section)

Question 9

Neonate sterile fields

Answer 9

Internal organs and tissues

Urinary bladder!

Question 10

Resident microbiota

Answer 10

Long-term members of the body’s normal microbiota

Question 11

Transient microbiota

Answer 11

Organisms that attempt to colonize the body, but fail due to competition, the immune system, or characteristics of body changes prevent growth

Question 12

Staphyloccous epidermis

Answer 12

Resident microbiota
Gram positive cocci, in clusters

Skin, nose, ears

Question 13

Group A Strep

Answer 13

Transient microbiota
Streptococcus pyogenes
Gram positive cocci, in chains

Question 14

Strict pathogens

Answer 14

Organisms always associated with disease

Not normal flora, such as mycobacterium tuberculosis, etc.

Question 15

Opportunistic pathogens

Answer 15

Tends to be members of normal microbiota

Take advantage of immunosuppression, etc., such as candida

Question 16

What kind of pathogens cause most infectious disease?

Answer 16

Opportunistic

Question 17

Pathogenicity

Answer 17

The ability of a microorganism to cause disease

Question 18

Virulence

Answer 18

Measure of pathogenicity

Question 19

Virulence factors

Answer 19

Toxins, etc., produced by organisms that enable it to infect, cause disease, or kill a host

Question 20

Carrier

Answer 20

Asymptomatic, but host to pathogen - potential to transmit

Can be transient, semi-, or permanent

Question 21

Transplacental entry

Answer 21

Mother to fetus

Ex. HIV, listeriosis, etc.

Question 22

Secretion entry to host

Answer 22

Mucosal - genital, nasal, GI, respiratory

Question 23

Stool entry to host

Answer 23

Fecal to oral

Question 24

Skin entry to host

Answer 24

Cuts, injury

Question 25

Blood entry to host

Answer 25

STIs, IV drug use

Question 26

Zoonotic entry to host

Answer 26

Animal to human, may be vector

Question 27

Arthropod entry to host

Answer 27

May be a reservoir or vector

Question 28

Barriers to prevent entry to host

Answer 28

Mechanical (skin, cilia) Enzymatic (lysozyme) Chemical (acidic pH) Immunity (complement, Ab) Commensals (niche environment) Physical (sheer forces, peristalsis)

Question 29

What must a bacteria do after entry to host to cause disease?

Answer 29

Adhesion

Question 30

Adhesion of bacteria

Answer 30

Binding of bacterial adhesin to host cell surface

Question 31

Tropism

Answer 31

Specific adhesin and receptor combinations

Question 32

Adhesins

Answer 32

Attachment proteins | Often associated with bacterial pili (fimbrae)

Question 33

How do most bacteria live?

Answer 33

Sessile (stationary) | NOT typically planktonic (freely moving)

Question 34

Biofilm

Answer 34

Bacteria encased in a substance (polysaccharide, DNA, etc.) of their own making Commonly moist and wet - showers, teeth, etc.

Question 35

How do bacterial cells in a biofilm differ from planktonic bacteria?

Answer 35

Generally slower metabolism Increased resistance to antibiotics Increased genetic exchange Resistance to disinfection = decreased diffusion, increased organic matter

Question 36

What do most bacterial infections have in common?

Answer 36

A biofilm | Ex. wound infection, otitis media, gingivitis, endocarditis

Question 37

Bacterial invasion into cells

Answer 37

Can hijack cells and mature in phagosome to promote survival | Can move between adjacent cells and get into blood without immune interaction

Question 38

Bacterial dissemination

Answer 38

Cause disease from sites metastatic to original infection

Question 39

Endotoxin

Answer 39

Lipid A portion of LPS

Question 40

Exotoxin

Answer 40

Directly harms tissue or destroy biologic activity Cytolytic enzymes Receptor binding proteins initiate toxic reactions

Question 41

AB toxins

Answer 41

``` A = active (carriers out destructive effects) B = binding (binds to receptor, allowing A site to carry out effects) ```

Question 42

Inhibition of protein synthesis exotoxin

Answer 42

Ex. Diphtheria | Blocks EF-2, preventing protein synthesis by ribosome

Question 43

Hyperactivation exotoxin

Answer 43

Ex. cholera Hijack cellular machinery and increases adenylate cyclase Results in massive cAMP production

Question 44

Nerve-muscle exotoxins

Answer 44

Ex. Tetanus or Botulism Tetanus - blocks inhibitory transmitter Botulism - inhibits ACH release from vesicles

Question 45

Superantigens

Answer 45

Bind both TCR and MHCII without Ag | "Cytokine storm" - life-threatening autoimmune-like response

Question 46

Bacterial encapsulation

Answer 46

Generally poorly antigenic | Prevents Ab or complement from binding

Question 47

Ag mimicry

Answer 47

Bacteria can produce compounds that the immune system sees as self

Question 48

S. pyogenes capsule

Answer 48

Hyaluronic acid

Question 49

S. areus protein A

Answer 49

Binds Fc portion of Ab and coats bacteria in host protein

Question 50

Ag variation/shift

Answer 50

Bacteria can quickly change Ag of cell surface proteins | "Moving" target for immune system

Question 51

Neisseria gonorrhoeae type IV pili

Answer 51

Many "silent" copies | Recombination between "silent" and "expressed" copies results in a highly variable Ag

Question 52

Inactivation Ab

Answer 52

Secretion of proteases that degrade a specific Ig

Question 53

Resistance to complement-mediated killing

Answer 53

Limiting access to membrane | Degradation of components of complement

Question 54

Bacteria escaping phagocytic clearance

Answer 54

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

Question 55

Regulation of virulence factors

Answer 55

Bacteria usually don't constitutively produce virulence factors

Question 56

Quorum sensing

Answer 56

Bacteria can sense the size of their population Regulation of gene expression in response to population size - bacteria acts as a group as opposed to individuals, to save on resources

Question 57

Bacteria that cause opportunistic infection in IV catheters

Answer 57

Staph. epidermis | Staph. aureus (MRSA)

Question 58

Bacteria that cause opportunistic infection in wound/surgical infections

Answer 58

Staph. aureus Klebsiella pneumoniae Pseudomonas aeruginosa

Question 59

Bacteria that cause opportunistic infection in endocarditis

Answer 59

Strep. viridans

Question 60

Bacteria that cause opportunistic infection in UTI

Answer 60

E. coli

Question 61

Bacteria that cause opportunistic infection in colitis

Answer 61

Clostridium difficile