Final; Invasive Pathogens of Mucosal Surfaces Flashcards Preview

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

Flashcards in Final; Invasive Pathogens of Mucosal Surfaces Deck (66):
1

What are the seven Fs of transmission

feces
food
fluids
fingers
flies
fomites
fornication

2

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

50-100

3

How many organisms does it typically take to cause disease

millions

4

What three things work to prevent infection in humans

natural barrier defenses
innate immunity
adaptive immunity

5

What assists in creating a physical barrier defense

natural anatomical and physiological properties
i.e. acidity (pH 1-2 to 9)

6

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

single cell layer

7

What are the layers of the natural barrier

water layer
mucous
glycocalyx
microvili

8

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

invade the epithelial cells
cleave tight junctions

9

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

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

10

What appears when there is a suppressed microbiota

pores; of which the infectious agents can get in

11

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

lysozyme (aka muramidase)

12

This has a bacteriostatic effect via sequestering iron

lactoferrin

13

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

cathelicidin

14

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

defensisn

15

α-defensins are produced by which cells

neutrophils and paneth cells (in the intestines)

16

β-defensins are produced by which cells

epithelial cells

17

Microboes with a low infectious dose tend to be what

acid resistant

18

Microbes use this to adhere to tissue to resist being shed

fimbriae/pili

19

This in microbial cell membranes effects of cationic antimicrobial peptides

cationic amino acids

20

These sequester iron in low iron environments

siderophores

21

These recognize microbes via PRRs

macrophages

22

Recognition of a PRR activates what

the microphages and the ability to kill many microbes
and the inflammatory response

23

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

cytokines

24

Which TLR is the most important for the pathogens we discussed

TLR-4

25

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

TNF-α; this opens a pathway for additional microbes

26

Microbes can develop this to resist phagocytosis

capsule

27

Microbes can develop mechanisms capable of neutralizing what

the phagocytic compartment of macrophages

28

The densest clusters of lymph nodes are found where

near mucosal tissues

29

This is generated in the lymph nodes

adaptive immune response

30

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

True

31

What are the two main types of invasive bacterial pathogens

salmonella spp.
shigella spp.

32

What type of symptoms are a result of invasive bacterial pathogens

small volume of stool
bloody stool
leukocytes in stool
tissue ulcerations

33

In which part of the intestine are invasive bacterial pathogens found

large intestine

34

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

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

35

How large is the inoculum size for Shigella

very small; 100-1000

36

This trait of Shigella facilitates survival through the stomach

acid resistance

37

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

acid resistance

38

Acid resistance occurs when Shigella are grown in which condition

anaerobically

39

Shigella will do what in the colon

multiply and colonize

40

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

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

41

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

the basal surface

42

Shigella enters via which cells via what

M cells; via outer membrane proteins called invasion plasmid antigens

43

Shigella is released where and causes what

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

44

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

it loosens the tight junctions

45

These cells will ingest Shigella facilitated by bacterial factors

epithelial cells

46

These lyse the phagosomal vesicle

bacterial proteins

47

Intracellular spread facilitated by this,

IcsA; an ATPase that causes actin polymerization

48

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

True

49

This develops when invaded cells die and slough off

an ulcer

50

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

True

51

What is different about S. dysenteriae type 1

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

52

These diseases are caused by salmonella

gastroenteritis
typhoid fever

53

How is salmonella spread

fecal (human or animal) - oral transmission

54

How large of an inoculum is required for salmonella

relatively large; 10-100 million

55

Which microbe is more acid sensitive; salmonella or shigella

salmonella

56

Salmonella in a low pH triggers what

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

57

When salmonella approaches the cells surface, what happens

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

58

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

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

59

Unlike shigella, salmonella does what upon entering vesicles

remains within the vesicle for many hours

60

Once salmonella is released into lamina propria what happens

it induces NaCl loss from the host cell

61

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

transient bacteremia

62

What is different about typhoid

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

63

What is dangerous about the typhoid spread

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

64

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

False; they do respond

65

How are invasive enteric pathogens identified

based upon symptoms and stool cultures

66

Antibiotic resistance was first identified where

in Shigella