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SP14 Microbiology > Final; Invasive Pathogens of Mucosal Surfaces > Flashcards

Final; Invasive Pathogens of Mucosal Surfaces Flashcards

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Biology 101 flashcards
1
Q

What are the seven Fs of transmission

A 
feces
food
fluids
fingers
flies
fomites
fornication
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2
Q

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

A

50-100

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3
Q

How many organisms does it typically take to cause disease

A

millions

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4
Q

What three things work to prevent infection in humans

A

natural barrier defenses
innate immunity
adaptive immunity

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5
Q

What assists in creating a physical barrier defense

A

natural anatomical and physiological properties

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

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6
Q

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

A

single cell layer

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7
Q

What are the layers of the natural barrier

A

water layer
mucous
glycocalyx
microvili

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8
Q

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

A

invade the epithelial cells

cleave tight junctions

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9
Q

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

A

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

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10
Q

What appears when there is a suppressed microbiota

A

pores; of which the infectious agents can get in

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11
Q

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

A

lysozyme (aka muramidase)

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12
Q

This has a bacteriostatic effect via sequestering iron

A

lactoferrin

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13
Q

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

A

cathelicidin

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14
Q

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

A

defensisn

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15
Q

α-defensins are produced by which cells

A

neutrophils and paneth cells (in the intestines)

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16
Q

β-defensins are produced by which cells

A

epithelial cells

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17
Q

Microboes with a low infectious dose tend to be what

A

acid resistant

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18
Q

Microbes use this to adhere to tissue to resist being shed

A

fimbriae/pili

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19
Q

This in microbial cell membranes effects of cationic antimicrobial peptides

A

cationic amino acids

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20
Q

These sequester iron in low iron environments

A

siderophores

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21
Q

These recognize microbes via PRRs

A

macrophages

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22
Q

Recognition of a PRR activates what

A

the microphages and the ability to kill many microbes

and the inflammatory response

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23
Q

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

A

cytokines

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24
Q

Which TLR is the most important for the pathogens we discussed

A

TLR-4

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25
Q

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

A

TNF-α; this opens a pathway for additional microbes

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26
Q

Microbes can develop this to resist phagocytosis

A

capsule

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27
Q

Microbes can develop mechanisms capable of neutralizing what

A

the phagocytic compartment of macrophages

28
Q

The densest clusters of lymph nodes are found where

A

near mucosal tissues

29
Q

This is generated in the lymph nodes

A

adaptive immune response

30
Q

True or False

Every mucosal surface is similar in all defensive mechanisms

A

True

31
Q

What are the two main types of invasive bacterial pathogens

A

salmonella spp.

shigella spp.

32
Q

What type of symptoms are a result of invasive bacterial pathogens

A

small volume of stool
bloody stool
leukocytes in stool
tissue ulcerations

33
Q

In which part of the intestine are invasive bacterial pathogens found

A

large intestine

34
Q

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

A

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

35
Q

How large is the inoculum size for Shigella

A

very small; 100-1000

36
Q

This trait of Shigella facilitates survival through the stomach

A

acid resistance

37
Q

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

A

acid resistance

38
Q

Acid resistance occurs when Shigella are grown in which condition

A

anaerobically

39
Q

Shigella will do what in the colon

A

multiply and colonize

40
Q

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

A

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

41
Q

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

A

the basal surface

42
Q

Shigella enters via which cells via what

A

M cells; via outer membrane proteins called invasion plasmid antigens

43
Q

Shigella is released where and causes what

A

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

44
Q

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

A

it loosens the tight junctions

45
Q

These cells will ingest Shigella facilitated by bacterial factors

A

epithelial cells

46
Q

These lyse the phagosomal vesicle

A

bacterial proteins

47
Q

Intracellular spread facilitated by this,

A

IcsA; an ATPase that causes actin polymerization

48
Q

True or False

IcsA can actually go into adjacent epithelial cells by passing lamina propria

A

True

49
Q

This develops when invaded cells die and slough off

A

an ulcer

50
Q

True or False

All species of Shagella induce inflammatory diarrhea with leukocytes in the stool

A

True

51
Q

What is different about S. dysenteriae type 1

A

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

52
Q

These diseases are caused by salmonella

A

gastroenteritis

typhoid fever

53
Q

How is salmonella spread

A

fecal (human or animal) - oral transmission

54
Q

How large of an inoculum is required for salmonella

A

relatively large; 10-100 million

55
Q

Which microbe is more acid sensitive; salmonella or shigella

A

salmonella

56
Q

Salmonella in a low pH triggers what

A

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

57
Q

When salmonella approaches the cells surface, what happens

A

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

58
Q

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

A

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

59
Q

Unlike shigella, salmonella does what upon entering vesicles

A

remains within the vesicle for many hours

60
Q

Once salmonella is released into lamina propria what happens

A

it induces NaCl loss from the host cell

61
Q

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

A

transient bacteremia

62
Q

What is different about typhoid

A

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

63
Q

What is dangerous about the typhoid spread

A

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

64
Q

True or False

Invasive enteric pathogens are not able to respond to environmental changes

A

False; they do respond

65
Q

How are invasive enteric pathogens identified

A

based upon symptoms and stool cultures

66
Q

Antibiotic resistance was first identified where

A

in Shigella

SP14 Microbiology (31 decks)

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