Final; Invasive Pathogens of Mucosal Surfaces

Question 1

What are the seven Fs of transmission

Answer 1

feces
food
fluids
fingers
flies
fomites
fornication

Question 2

For some bacteria, as few as how many organisms can cause disease

Answer 2

50-100

Question 3

How many organisms does it typically take to cause disease

Answer 3

millions

Question 4

What three things work to prevent infection in humans

Answer 4

natural barrier defenses
innate immunity
adaptive immunity

Question 5

What assists in creating a physical barrier defense

Answer 5

natural anatomical and physiological properties

i.e. acidity (pH 1-2 to 9)

Question 6

How many cell layers protect the interior of the body from billions of microbes on mucosal surfaces

Answer 6

single cell layer

Question 7

What are the layers of the natural barrier

Answer 7

water layer
mucous
glycocalyx
microvili

Question 8

What are the two ways in which the pathogens can pass through the epithelial layer

Answer 8

invade the epithelial cells

cleave tight junctions

Question 9

What is a main reason we are not always infected with gram-negative pathogens

Answer 9

there are so many normal flora bacteria in out intestines; out-compete infectious agents

Question 10

What appears when there is a suppressed microbiota

Answer 10

pores; of which the infectious agents can get in

Question 11

This cleaves the β 1,4-glycosidic linkages between NAM and NAG

Answer 11

lysozyme (aka muramidase)

Question 12

This has a bacteriostatic effect via sequestering iron

Answer 12

lactoferrin

Question 13

This disrupts the bacterial membranes of GM- and GM+ (as well as fungi)

Answer 13

cathelicidin

Question 14

This creates pores in microbes (all microbes can be affected)

Answer 14

defensisn

Question 15

α-defensins are produced by which cells

Answer 15

neutrophils and paneth cells (in the intestines)

Question 16

β-defensins are produced by which cells

Answer 16

epithelial cells

Question 17

Microboes with a low infectious dose tend to be what

Answer 17

acid resistant

Question 18

Microbes use this to adhere to tissue to resist being shed

Answer 18

fimbriae/pili

Question 19

This in microbial cell membranes effects of cationic antimicrobial peptides

Answer 19

cationic amino acids

Question 20

These sequester iron in low iron environments

Answer 20

siderophores

Question 21

These recognize microbes via PRRs

Answer 21

macrophages

Question 22

Recognition of a PRR activates what

Answer 22

the microphages and the ability to kill many microbes

and the inflammatory response

Question 23

These are part of the inflammatory response that also initiate the adaptive immune response and recruit other cells

Answer 23

cytokines

Question 24

Which TLR is the most important for the pathogens we discussed

Answer 24

TLR-4

Question 25

Inflammatory cytokines such as what can disrupt the tight junctions between epithelial cells

Answer 25

TNF-α; this opens a pathway for additional microbes

Question 26

Microbes can develop this to resist phagocytosis

Answer 26

capsule

Question 27

Microbes can develop mechanisms capable of neutralizing what

Answer 27

the phagocytic compartment of macrophages

Question 28

The densest clusters of lymph nodes are found where

Answer 28

near mucosal tissues

Question 29

This is generated in the lymph nodes

Answer 29

adaptive immune response

Question 30

True or False | Every mucosal surface is similar in all defensive mechanisms

Answer 30

True

Question 31

What are the two main types of invasive bacterial pathogens

Answer 31

salmonella spp. | shigella spp.

Question 32

What type of symptoms are a result of invasive bacterial pathogens

Answer 32

small volume of stool bloody stool leukocytes in stool tissue ulcerations

Question 33

In which part of the intestine are invasive bacterial pathogens found

Answer 33

large intestine

Question 34

What are the four species of Shigella that are distinguished by the O antigen

Answer 34

S. dysenteriae S. flexneri S. boydii S. sonnei

Question 35

How large is the inoculum size for Shigella

Answer 35

very small; 100-1000

Question 36

This trait of Shigella facilitates survival through the stomach

Answer 36

acid resistance

Question 37

This is controlled by a global regulatory system of genes under the control of RpoS made in the stationary phase

Answer 37

acid resistance

Question 38

Acid resistance occurs when Shigella are grown in which condition

Answer 38

anaerobically

Question 39

Shigella will do what in the colon

Answer 39

multiply and colonize

Question 40

What is the series of events that happens when Shigella grows in an anaerobic condition

Answer 40

it will first turn on virulence genes that aid in acid resistance then when it reaches the acid, it turns on invasion genes

Question 41

The mucosal surface is resistant to a Shigella invasion, but what is not

Answer 41

the basal surface

Question 42

Shigella enters via which cells via what

Answer 42

M cells; via outer membrane proteins called invasion plasmid antigens

Question 43

Shigella is released where and causes what

Answer 43

released into lamina propria, ingested by the macrophages and inflammation causes illness

Question 44

When the neutrophils get into the lumen and attack a pathogen, what happens

Answer 44

it loosens the tight junctions

Question 45

These cells will ingest Shigella facilitated by bacterial factors

Answer 45

epithelial cells

Question 46

These lyse the phagosomal vesicle

Answer 46

bacterial proteins

Question 47

Intracellular spread facilitated by this,

Answer 47

IcsA; an ATPase that causes actin polymerization

Question 48

True or False | IcsA can actually go into adjacent epithelial cells by passing lamina propria

Answer 48

True

Question 49

This develops when invaded cells die and slough off

Answer 49

an ulcer

Question 50

True or False | All species of Shagella induce inflammatory diarrhea with leukocytes in the stool

Answer 50

True

Question 51

What is different about S. dysenteriae type 1

Answer 51

it produces shiga toxin; which kills intestinal epithelial and endothelial cells and disrupts Na absorption

Question 52

These diseases are caused by salmonella

Answer 52

gastroenteritis | typhoid fever

Question 53

How is salmonella spread

Answer 53

fecal (human or animal) - oral transmission

Question 54

How large of an inoculum is required for salmonella

Answer 54

relatively large; 10-100 million

Question 55

Which microbe is more acid sensitive; salmonella or shigella

Answer 55

salmonella

Question 56

Salmonella in a low pH triggers what

Answer 56

expression of at least 40 proteins found on pathogenicity islands on large virulence plasmids

Question 57

When salmonella approaches the cells surface, what happens

Answer 57

induces the activity of cell signaling pathways and cause an increase in cellular Ca++

Question 58

When salmonella induces the cell signaling and Ca increase, what also happens

Answer 58

it induces surface ruffles and uptake of the organisms (microbe directed phagocytosis)

Question 59

Unlike shigella, salmonella does what upon entering vesicles

Answer 59

remains within the vesicle for many hours

Question 60

Once salmonella is released into lamina propria what happens

Answer 60

it induces NaCl loss from the host cell

Question 61

Macrophages engulf most of the salmonella, but some escape and cause what

Answer 61

transient bacteremia

Question 62

What is different about typhoid

Answer 62

it will enter the lymphatic system and will survive and grow in macrophages throughout the body

Question 63

What is dangerous about the typhoid spread

Answer 63

strictly a human reservoir asymptomatic carriers (typhoid Mary) carriers have colonized gall bladders

Question 64

True or False | Invasive enteric pathogens are not able to respond to environmental changes

Answer 64

False; they do respond

Question 65

How are invasive enteric pathogens identified

Answer 65

based upon symptoms and stool cultures

Question 66

Antibiotic resistance was first identified where

Answer 66

in Shigella