Mucosal surfaces, Enterobacteriacea-diarrheal diseases Salmonella and Shigella- invasive bacterial pathogens MM (2/27/18) Flashcards
(113 cards)
1
Q
types of gram-negative pathogens
A
Enterobacteriaecaeae
Vibrinoaceae
2
Q
what is mucosal surface
A
interacts with air and secretes mucus
3
Q
defense of mucosal surface
A
innate immunity, adaptive immunity, nonspecific barriers
4
Q
why study GI diseases
A
lots of people get it, 500,000 in hospital, 5000 deaths
$10 bill in treatment\
begin in the oral/fecal route
5
Q
why E. Coli outbreak in germany in 2011
A
alfa sprouts
852 cases of hemolyric uremic syndrome and 32 people died
6
Q
E. Coli in chipotle
A
53 cases, 20 hospitalization
0 death
shiga toxin
7
Q
how gram negative mucosal pathogens leaves the feces to get to your mouth
A
feces food fluid fingers flies formites fornication
8
Q
inoculum size
A
how many needed to cause disease (some low-shigella and EHEC, EIEC, others high-ETEC, EPEC,vibrio)
9
Q
natural barrier defences in GI
A
acidity:1-2 in stomach then 9 in Small intensine
Motility: stuff moves through Small intestine fast so bacteria can’t atach
Mucous layer and underlying glycocalyx
Tight juntion
10
Q
where in the GI do we get lots of bacteria
A
near the end
11
Q
what blocks infection with gram negative pathogen
A
normal flora natural defenses of GI Lysozymes (doesn't work too well against gram negative though to unexposed cell wall) Lactoferrin Cathelicidin Defensins Secretory immunoglobulins
12
Q
action of lysozyme
A
cleaves beta 1,4-glycosidic linkage between N-acetylnuramic acid and N-acetylglucosamine
13
Q
action of lactoferrin
A
stops bacteria by sequestering iron
14
Q
action of cathelicidin
A
disrupts bacterial membrane of Gm- and Gm+ and fungi
15
Q
action of Defensins
A
creates pores on all microbes
16
Q
who produced alpha-defensins
A
neutrophils and paneth cells (intestine
17
Q
who produced beta defenisn
A
epithelial cells
18
Q
how do bacteria overcome innate barrier defneces
A
acid resitance
Fimbriae/pili_adhere to tissue and avoid being spread
BActerial strucutre
19
Q
what bacterial tend to be acid resitant
A
low infectious dose (Shigella and Enteroinvasive E Coli
20
Q
What bacterial strucutres aid in overcoming pathogenic innate barrier densences
A
gram-/gram+ cell membrane sesnitive to bactericidal compounds
Cationic amino acids into cell membrane to reduce efects of cationic antimicrobial peptides
Siderophoers sequester iron
21
Q
what immunity are macrophages part of
A
cell mediated immunity via TH1
use PAMPS
22
Q
whta receptor is activated by gram negative bacteria
A
TLR4
23
Q
activation of pattern recognition receptors on macrophages laed to
A
inflammatory response
24
Q
morphology of enterobacteriaceae family
A
gram -
no spor
non acid fast
rods (coccobacilli to elongate filamentous rods)
25
growth of enterobacteriaceae family
faculataticve growth and visible after 12-18 hours
26
toxins on enterobacteriaceae
all endotoxin, some secrete exotoxin
27
cell wall components of enterobacteriaceae family
antignic:
o- outer antigen, LPS
k- polysaccharide capsule
H- flagella
28
source of serotypes of in bacterial species due to
cell surface antigens
29
where do enterobacteriaceae infections come from
external from environment and animal
| not: salmonella ser typhi and shigella: strickly human
30
how does enterobacteriaceae cause a pathogen
opportunistic
31
most common infections by enterobacteriaeceae
UTI's and acute diarrhea
32
what do E. Coli ferment
lactose
33
what do E. coli produce
indole
34
how to determine serotype of E. coli
O, K, and H antigens
35
E coli pili
type 1: most common, bind D mannose residues on epitheliail cells with an on/off
p pili: bind digalactoside found within urinary tract and erythrocytes
other: common to diarrheal binding to erythrocytes
36
E. coli toxins
alpha hemolysisn
Cytoxoic necrotizing factor
Shiga toxin
37
action of alpha-hemolysin
pore forming
38
action of cytoxoic necrotizing factor (CNF)
A-B toxin that produces G proteins (disrupt intraceullar signalling)
39
action of shiga toxin(Stx)
A-B toxin that blocks pr synth by ribosomal modification
40
pathogenic E coli
```
UropathogenicE. coli (UPEC)
EnterotoxigenicE. coli (ETEC)
EnteropathogenicE. coli (EPEC)
EnteroinvasiveE. coli (EIEC)
EnterohemorrhagicE. coli (EHEC)
EnteroaggregativeE. coli (EAEC)
```
41
Enteropathogenic E. Coli (EPEC) causes
common causative agenet of nursery outbreaks in developing coutnries
42
adult inoculum of Enteropathogenic E. Coli (EPEC)
10^8 to 10^10 CFU
43
how does Enteropathogenic E. Coli (EPEC) attach to distal small intestinal enterocytes
bundle-forming pili (Bfp)
44
how does Enteropathogenic E. Coli (EPEC) inject into host cell
Type III secretion system to inject over 30 E. Coli secretion proteins(not toxin though)
45
how does Enteropathogenic E. Coli (EPEC) formation of attaching and effacing (A/E) lesion
Intimin-Tir interaction
46
how do we think Enteropathogenic E. Coli (EPEC) cause diarrheal disease
effacement of the microvilli and disruption of tight junctions
47
where does Enterohemorrhhagic E. Coli (EHEC) occur
developed countries
48
source of Enterohemorrhhagic E. Coli (EHEC)
animal products, unpasteurized juice, fresh veggies
49
inoculum of Enterohemorrhhagic E. Coli (EHEC)
100 CFU
50
what genes does Enterohemorrhhagic E. Coli (EHEC)
similar to EPEC (eae genes)
51
what toxin does Enterohemorrhhagic E. Coli (EHEC) produce
toxin the leads to hemolytic uremic syndrome (bloody diarrhea)
52
most notorious Enterohemorrhhagic E. Coli (EHEC)
E. coli O157:H7
53
primary reservoid of Enterohemorrhhagic E. Coli (EHEC)
cattle
54
how does Enterohemorrhhagic E. Coli (EHEC) cause problems
causes attaching effacing lesion in colon via long polar fimbriae leading to A/E lesion similar to EPEC
Shiga toxin: hemorrhagic colitis, Hemolytic uremic syndrome
55
what does Enterohemorrhhagic E. Coli (EHEC) act on
shiga toxinthe blood vessels under the epithelial cells of the villus
56
what does Enteroinvase E coli (EIEC) cause
similar to shigella, mild version of shigellosis
57
who gets Enteroinvase E coli (EIEC)
children under 5 in developing countires
58
where is Enteroinvase E coli (EIEC) found
contaminated food and water
| humans the only reservoid
59
what does Enteroaggregative E. coli (EAEC) cause?
watery diarrhea that last longer than 14 days
60
how does Enteroaggregative E. coli (EAEC) do to cause problems
tight adherence to epithelial cells in a stacked brick pattern
61
symptoms of intestinal E. Coli infections
```
usually a couple days after inoculation and self limiting
Except::
EAEC: can last for weeks
EPEC: can be chronic
EHEC and EIEC: bloody diarhhea
```
62
diagnosis of E. Coli mediated disease
not best to use culture because we have it in our bottle as part of the flora
assays available to detect toxins/genes with virulences
Screening tests
63
why not do assays
healthy people can test positive
| Expensive
64
how to do a screening test for O157:H7
grown on MacConkey agar supplemented with sorbital (not lactose). cannot ferment sorbital so colonies will have no color
65
how to treat diarrheal disease
supportive therapy, keep hydrated
66
treating hemorrhagic colitis/HUS
hemodialysis/hemapheresis
67
why not use antimotility agenst on diarrheal disease
because it keeps the bacteria from leaving
68
what is shigella
specialized E coli
69
antigens of shigella
O and K, but no H (O is main)
70
do shigella invade cells
yes, and multiple within epithelial cells
71
what toxin does shigella produce
shiga toxin
72
4 types of shigella
* Shigelladysenteriae(serogroup A) –Type 1 causes most severe disease
* Shigellaflexneri(serogroup B) –Most common
* Shigellaboydii(serogroup C)
* Shigellasonnei(serogroup D) –Most common
* Subgroups found within each of these.
73
who does shigellosis infect
strictly human (150 million cases) and 600k global deaths per year
74
how id shigellosis spread
food.water contamination by humans
75
incidence and prevalence of shigellosis is related to whay
personal and community sanitiation, so wars enable outbreak
76
inoculum of shigellosis
as little as 10 organisms
77
what does shigellosis resist
acid resistant
78
pathogensis of shigella
infect M cells via invasion plasmid antigenin colon and pyers patch
enter macrophage, and lyse phagosome, killing macrophage
enters in the lamina propria to infect the basal part of enterocyte using invastion plasmid antigens (IpaA and IpaD) using type 3 secretion
uses actin fillaments to move around into new cells
eveutally killls epitehlial cells
79
shigella infection cycle is like
Listeria monocytogenes
80
diseases of shigella
ulcer develops when invaded cells die and foll off
| Diarrhead as response of inflammatory response
81
what do ulcers do for shigella
allow shigela to reach lamina propria
82
what kind of diarrhea is a reuslt of shigella
classic dysentery - small volume diarrhea, leukocytes, and RBC's
83
Shigella dysenteriae type 1 mortality rate
high mortality even with adults, alwaus have shiga toxin
84
shigella dysenteriae type 1 results in
kills intestinal epithelial and endothelial cells
Disrupts Na absorption
Toxin can be systemic
85
immunologic protection of shigella
does produce immunological protection, but no cross protection
86
diagnosis of shigella
stool culture, O antigen aglutination tests to determine serotype
87
how to treat diseases by shigella
self limiting, but antibiotics like ciproflaxacin and azithromycin can shorten illness time
88
vaccine for shigella
no, but in the works
89
two types of salmonella
S. bongori
| S. enterica
90
medicall important infections arise from what salmonella
S. enterica
91
subspecies of S. enterica
multiple: medicall importatn belong to the enterica subspecies
92
naming salmonella species
diff subspecies have different disease
go by species name, subspecies, then serotype
but sorten to jus first part of species name, then serotype
93
salmonella enterica gastroenteritis occures where and why
industrialized nation and improper food handling, food born, eggs and poltry
94
inoculum range of salmonella enterica gastroenteritis
200-10^6, due to acid amount
95
symptoms of salmonella enterica gastroenteritis
abdominal pain, nausea, vomiting, and diarrhea
96
how long does salmonella stay in yo
recover after 3-4 days, but cary for 20 weeks (5% OF PATIENTS)
97
how to get salmonella
fecal (human or animal)-- oral transmission
98
acid sensitivey of salmonella vs shigellae
more acid sensitive than shigellae
99
low pH causes salmonella to do what
express 40 PR found on pathogenicity islands on large virulence plasmds
100
where does salmonella infections colonize
small intestine
101
how does sallmonella infect
1. Organism makes contact with M cell (likely via Type 1 pili) and injects effector molecules into cell with Type III secretion system.
2. These events induce surface “ruffles” and uptake of the organisms (microbe-directed phagocytosis).
3. Multiplies and remains within cell vesicles for many hours (unlike Shigella).
4. Organisms released to lamina propria, inflammatory response is activated, ingested by phagocytes, then kills phagocyte.
5. Macs engulf most, but some escape to cause a transient bacteremia
- -the typhoid serovarswill survive and grow within the macrophages
102
why does Salmonella typhi cause
no animal reservoid, sticktly human
| but also asymptomatic carriers
103
salmonella typhi carries have what colonized in them
gall bladders, and organisms can be cultured from their feces
104
typhi can surive how long in the macrophage
long time due to inhibiting oxidative burst
105
how does salmonella typhi enter the lymph
via macrophage via mesenteric lymph nodes, spleen, liver, bone marrow, then blood
106
whay of typhi causes fever
endotoxin
107
how long can typhi fever last
weeks if untreated
108
prolonged infected by typhi results in
perforated bowel
109
immunity of salmonella
Humoral (Th2 and cell-mediated (Th1)
110
what does salmonella do with host response to survive long
exploit host response
111
how to identity salmonella
culture from stool or blood, identify O serogroup
112
how to treat gastroenteritis from salmonella
fluid/electrolyte replacement
| (antibioitcs for severe cases cuz it can increase the duration of infection and the incidence of the carrier state
113
how to treat typhoid fever
antibiotics such as ciproflaxacin in the first line
