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MicroBiology Exam 2 > 2/27: mucosal surfaces, enterobacteriaceae-diarrheal diseases > Flashcards

2/27: mucosal surfaces, enterobacteriaceae-diarrheal diseases Flashcards

1
Q

Name 3 members of the enterobacteriaceae family that cause diarrhea

A
  1. e. coli
  2. salmonella species
  3. shigella species
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2
Q

Mucosal surface definition and examples

A

any surface that interacts with air and has glands that secrete mucous

examples: oral cavity, respiratory tract, repro/urinary tract, GI

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3
Q

What are the defenses of mucosal surfaces?

A

innate immunity, adaptive immunity and non-specific barriers (the cells themselves, mucous are physical barriers against infection)

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4
Q

E. Coli 0104:H4 OUtbreak
caused by ____
3500 causes, 800 caused by ____
32 people died, surprising because ____

A

caused by alfalfa sprouts, cucumbers
800 cases associated with hemolytic uremic syndrome
32 death is surpsing because this is rare for e. coli infections

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5
Q

E. Coli 0:26 outbreak
caused by ____
produced ____ (associated with bloody diarrhea)
mortality?

A

caused by chipotle
produced shiga toxin (associated w/ bloody diarrhea)
50 cases, half hospitalized, nobody died

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6
Q

Why do oral healthcare practitioners care about GI diseases?

A

they originate in the ORAL CAVITY due to fecal matter contamination
How does it get there? 7 F’s

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7
Q

What are the 7F’s?

A

how fecal matter contamination enters the oral cavity

feces
food
fluids
fingers
fomites
fornication
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8
Q

What is an inoculum size?

Low inoculum size range? spread by?

high inoculum size range? spread by?

A

inoculum size = amount of bacteria it takes to make someone sick (ID, infectious dose)

low ID: 50-100, usually spread by fomites or fingers so it doesn’t take as much

high ID: require millions of organisms to cause disease, so you would need bacteria to be in your food/drink

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9
Q

Name the 5 natural barrier defenses of the GI system

A
  1. natural anatomical and physiological properties
  2. acidity (and change in acidity) (stomach = 1-2, duodenum = 9)
  3. motility (chime moves through stomach and small intestine quickly, so bacteria need to be able to directly adhere to epithelium or mucous layer)
  4. mucous layer
  5. tight junctions hold epithelial cells together, prevent penetration of bacteria
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10
Q

normal flora in GI provides a physical barrier by ____

A

competing with pathogens for nutrients and oxygen

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11
Q

Name the 6 secretory antimicrobial compounds found in the GI system

A
  1. lysozymes
  2. lactoferrin
  3. cathelicidin
  4. alpha defensins
  5. beta defensins
  6. secretory Igs
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12
Q

Describe how lysozymes defend against bacterial invasion of GI tract

A

cleaves NAG and NAM linkage (although the murein isn’t directly exposed in gram Negs it still works)

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13
Q

Describe how lactoferrin defend against bacterial invasion of GI tract

A

sequesters/hides iron from bacteria

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14
Q

Describe how cathelicidin defend against bacterial invasion of GI tract

A

disrupts gram pos and gram neg membranes

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15
Q

Describe how alpha defensins defend against bacterial invasion of GI tract

made by ____

A

create pores in microbes

made by neutrophils and intestinal paneth cells

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16
Q

Describe how beta defensins defend against bacterial invasion of GI tract

made by ____

A

creates pores in microbes

made by epithelial cells

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17
Q

Describe how Igs defend against bacterial invasion of GI tract

A

secretes IgA specifically

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18
Q

What are the 3 ways that pathogenic bacteria overcome the innate barrier defenses of GI tract?

A
  1. acid resistance
  2. fimbriae/pilli
  3. bacterial structures
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19
Q

how does acid resistance help bacteria overcome innate barrier defenses in GI?

how does ID # play a role?

A

just enough acid resistance to get them through the stomach and into duodenum

microbes with low ID tend to be more acid resistant

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20
Q

How do fimbriae/pilli help bacteria overcome innate barrier defenses in GI?

A

helps microbe adhere to tissues

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21
Q

How do bacterial structures help bacteria overcome innate barrier defenses in GI?

A

bacteria can slightly change their cell membranes to evade bactericidal compounds, can incorporate cationic amino acids into cell membrane to reduce effect of cationic antimicrobial peptides

can sequester iron through siderophores

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22
Q

Macrophages are important for mucosa immunity because they recognize _____

TLR4 recognizes ____

A

macrophages recognize PAMPs and activate and kill many of the microbes

TLR4 recognizes LPS of gram negative bacteria

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23
Q

Describe the enteroibacteriaceae family general info

A

gram negative
range from coccobacilli to elongated rods
facultative aerobes
don’t form spores
ALL HAVE ENDOTOXIN LPS, some produce and secrete exotoxin

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24
Q

Enterobacteriaceae family all have cell wall components that are antigenic. 3 main types:

A
  1. O antigen (outer antigen, LPS)
  2. K antigen (polysaccharide capsule, not all have)
  3. H antigen (flagella)
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25
What is a serotype? Define e.coli O157:H7
variations within a bacterial species due to the difference in cell wall surface antigens e.coli O157:H7 mean O-antigen LPS is type 157 and H-antigen flagella is type 7
26
Escherichia coli most ferment ___ and produce ___
ferment lactose | produce indole
27
Escherichia coli serotypes are determined by ___ antigens
O, K, H
28
Most common type of pili on escherichia coli is ____
type 1
29
Type 1 pili on escherichia coli binds ____
d-mannose on epithelial cells this has an on/off switch that turns ON in presence of ACID
30
The p pili on escherichia coli binds ____
digalactoside in urinary tract and in some erythrocytes
31
Other pili (not type 1 or p pili) on escherichia coli are common to _____ and bind to ____
common to diarheal strains bind enterocytes
32
What are the 3 main toxins associated with scherichia coli?
1. alpha-hemolysin 2. CNF (cytotoxic necrotizing factor) 3. shiga toxin
33
Alpha-hemolysin toxin of e.coli forms ___
pores
34
CNF (cytotoxic necrotizing factor) toxin of e.coli does what?
a-b toxin produces g proteins disrupts intracellular signaling
35
Shiga toxin of e.coli does what?
a-b toxin | blocks protein synthesis by modifying ribosomes
36
"Pathogenic e. coli is SELF LIMITING" | what does this mean?
bacteria are being flushed out and cell turnover is very high in the colon so anything tha tattahces will be gone soon
37
What are exceptions to "pathogenic e. coli is self limiting"
EAEC = diarhea for weeks EPEC = can be chronic EHEC and EIEC = bloody diarhea bc shiga toxin
38
EPEC (enteropathogenic e. coli) has ___ ID causes ___ outbreaks occur in _____
high ID affects SMALL INTESTINE outbreaks in nurserys and developing countries
39
What are the pili for EPEC (enteropathogenic e.coli)
Bfp (bundle-forming pili) | adheres to distal small intestine enterocytes
40
EPEC (enteropathogenic e.coli) uses ___ secretion system
type III | injects e.coli secretion proteins into host cell
41
EPEC (enteropathogenic e.coli) uses specific protein intimin-Tir What does this do?
it is injected into the cell, goes to the membrane and allows bacteria to attach to the cell this facilitates actin polymerization to form a "pedestal" for the bacteria to sit in
42
What toxin does EPEC produce?
none. | doesn't invade = doesn't produce toxin
43
EPEC likely causes diarrhea due to ____
defacement of microvili and tight junctions
44
``` EHEC (enterohemerrhagic e.coli) has ___ ID causes ___ ___ toxin occurs in ___ ```
``` low id shiga toxin causes bloody diarrhea occurs in developed countries comes from animal products or vegetables/fruits due to cow manure fetilizer ```
45
EHEC has shiga toxin which produces bloody diarrhea. | This can lead to _____
hemolytic uremic syndrome
46
EIEC (enteroinvasive e.coli) is similar to ____ infection
similar to shigella infections | causes milder form of shigellosis
47
EIEC (enteroinvasive e.coli) is acquired through ____
contaminated food/water | humans are the only reservoir
48
EIEC (enteroinvasive e.coli) attaches to the host cell and.....
evades the endosome multiplies inside cytoplasm uses host cell actin to push through neighboring cells
49
EAEC (enteroaggregative e.coli) leads to ____ that lasts ____
watery diarrhea that lasts up to 2 weeks | involved tight adherence of bacteria to epithelial cells in "stacked brick pattern"
50
E.coli o104:h7 was which strain of e.coli?
eaec
51
What is shigella?
specialized e.coli that only has O and K antigens because no H antigen = no flagella (non motile)
52
All species of shigalla are einvasive and multiply within ___
epithelial cells
53
Do all forms of shigella produce the shiga toxin?
no
54
What are the 4 species of shigella?
shigella dysenteriae - type 1, most serious, bloody diarrhea shigella flexner - most common shigella boydii shigella sonnei - common, no bloody diarrhea
55
Shigellosis strictly infects ___ __ ID ___ resistant
strictly infects humans ID = 10 low acid resistant
56
Shigellosis pathogenesis: | attaches to __ cells via ___
attaches to M cells via Ipa (invasion plasmid antigens)
57
Shigellosis pathogenesis | Where in an M cell is it going to invade?
after shigella escapes the phagosome, it kills the macrophage. now it can get to the LAMINA PROPRIA
58
Shigellosis uses ___ secretion system this helps inject ____ into what part of an enterocyte?
type III helps inject IpaA and IpaD into BASOLATERAL SURFACE OF ENTEROCYTE
59
Shigella injects IpaA and IpaD into ____ of enterocyte
basolateral surface of enterocyte
60
How does shigella get from the basolateral surface of enterocyte into the enterocyte?
it properls itself into the enterocyte using host cytoskeletal rearrangement
61
Once inside the enterocyte, how does shigella move around? because no h antigen = no flagella = non motile
moves around using HOST ACTIN
62
When shigella-invaded cells die and are sloughed off, what hapepns?
ulcer is formed at site of enterocyte death diarrhea results from infalmmation presents as CLASSIC DYSTENTERY (small volume diarrhea + leukocytes + RBC)
63
Immunity against shigellosis?
produces antibodies | not protective over other serotypes
64
How do you diagnose shigellosis?
stool culture or O-antigen agglutination
65
Salmonella typhimurium causes ___ ID _____ acquired from ____
gastroenteritis ID ranges from high to low acquired from egg/poultry dishes
66
Which is more acid sensitive: shigella or salmonella?
salmonella
67
T/F: Salmonella typhimurium is transmitted via fecal-oral transmission from human to human
false fecal-oral transmission from huamnd or animals
68
Salmonella typhimurium bacteria attaches to ___ cells uses ___ secretion system to inject proteins into host
M cell Type III secretion system
69
Salmonella typhimurium bacteria causes a ___ apperance of host cell
ruffled as it uptakes the bacteria
70
Salmonella typhimurium bacteria remains in the host cell to multiply for hours. it is then released into the ____, stimulating a ____ response
lamina propria stimulating an inflammatory response bacteria is then taken up by phagocytes (mostly macrophages)
71
If salmonella typhimurium escapes phagocytosis in the lamina propria, what does it do?
causes bacteremia
72
T/F salmonella typhi is strictly human pathogen that can have asymptomatic carriers
true
73
Where do salmonella typhi multiply? | how?
in macrophages | by inhibiting oxidative bursts
74
What immune response oes salmonella typhi cause?
th1 and th2
75
diagnosis of salmonella typhi?
stool sample or blood to identify the O serogroup

MicroBiology Exam 2 (8 decks)

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