lecture 21 chapter 24 Flashcards
(226 cards)
1
Q
long term solution of cholera outbreak in Haiti
A
improvements to country’s water treatment and sanitation facilities
2
Q
digestive tract
A
hollow tube from mouth to anus
3
Q
gastrointestinal tract refers to
A
stomach and intestines
4
Q
accessory organs of digestive system
A
salivary glands, liver, pancreas
5
Q
function of digestive system is to
A
convert foods into absorbable nutrients to use for energy and raw materials for growth
6
Q
mucous membranes are _____ thick and operates microbial population from underlying tissue
A
one cell layer
7
Q
damage to mucosal barrier allows ____ to penetrate
A
microbes
8
Q
ingested pathogens often have mechanisms to breach the ______
A
mucosal barrier
9
Q
causative agent of helicobacter pylori gastritis
A
helicobacter pylori
10
Q
bacterial characteristics of helicobacter pylori gastritis
A
short, curved, gram-negative microaerophile with multiple sheathed polar flagella
11
Q
signs and symptoms of helicobacter pylori gastritis
A
most infections are asymptomatic, gastritis with belching and vomiting may occur
12
Q
chronic gastritis can lead to _____
A
stomach cancer
13
Q
peptic ulcers produce _______
A
localized abdominal pain, tenderness, bleeding
14
Q
helicobacter pylori survives acidic environment of _____
A
stomach
15
Q
helicobacter pylori produces _____
A
urease
16
Q
bacterium burrows within _____ that coats stomach lining
A
mucus layer
17
Q
______ promotes flow of urea, induces apoptosis in epithelial cells, interferes with T cells
A
VacA (vacuolating cytotoxin)
18
Q
______ in strains with higher risk of cancer; alters host cytoskeleton, cell signaling
A
CagA (cytotoxin-associated gene)
19
Q
damage to epithelial cells and inflammatory response results in
A
decreased mucus production, cell damage
20
Q
_____ of those effected with stomach cancer are infected with helicobacter pylori gastritis
A
90%
21
Q
about _____ adults in US infected with H. pylori
A
1 in 5
22
Q
infection rates of helicobacter pylori gastritis highest in
A
low socioeconomic groups
23
Q
helicobacter pylori gastritis likely transmitted via
A
fecal-oral route
24
Q
helicobacter pylori gastritis often found in
A
well water
25
treatment and prevention of helicobacter pylori gastritis
antibiotics plus medication to inhibit acid production
26
incubation period of helicobacter pylori gastritis
usually undetermined
27
signs and symptoms of gastroenteritis
diarrhea, loss of appetite, nausea, vomiting, sometimes fever
28
incubation period of gastroenteritis
1-3 days
29
if gastroenteritis in small intestine, then
abundant, watery diarrhea (bacterial or viral)
30
if gastroenteritis in large intestine, then
small amounts of diarrhea with mucus, pus, and sometimes blood (mostly bacteria)
31
dysentery is
blood and pus in feces
32
virulence genes are often shared by ______ across different species
horizontal transfer
33
infectious dose typically related to ______, organisms must survive passage through stomach
acid tolerance
34
attachment of ______ needed for infection
pathogen
35
gastroenteritis disrupts _____ in small intestine; can result in dehydration; potentially fatal, especially in the very young and very old
fluid exchange
36
gastroenteritis causes _______ in large intestine
strong inflammatory response
37
mechanisms of gastroenteritis include
alteration of intestinal epithelial cells, cell invasion, exotoxin production
38
enterotoxins cause
water and electrolyte loss
39
cytotoxins cause
cell death
40
some cytoxins can be absorbed into bloodstream, causing
systemic effects
41
how is diarrheal disease transmitted?
fecal-oral (ingestion of contaminated food/water, sexual practices with oral-anal contact)
42
pathogens with low infectious dose can be transmitted by _______
person-to-person contact
43
________ are important control measures for diarrheal disease
sewage treatment, hand washing, chlorination of drinking water
44
_______ in the US is a DNA subtyping resource that helps track illness caused by specific intestinal pathogens
PulseNet
45
treatment and prevention of diarrheal diseases
oral rehydration therapy (ORT)
46
oral rehydration therapy is mixture of
glucose and salts
47
is there a treatment for viral diarrhea?
no
48
antimicrobial medications can sometimes prolong bacterial infection as they suppress _______, zinc supplements may decrease severity of disease
normal microbiota
49
causative agent of cholera
vibrio cholerae
50
bacterial characteristics of vibrio cholerae
curved, gram-negative rod
51
several serotypes of vibrio cholerae grouped by
O antigen
52
01 serotype responsible for
a previous pandemic
53
cholera is ____ and can grow in alkaline conditions
halotolerant (salt tolerant)
54
incubation period of cholera
18-48 hours
55
"rice water stool" appearance can amount to _______ a day in cholera; dehydration can lead to organ failure and death
20 liters
56
signs and symptoms of cholera
vomiting may occur at onset; severe muscle cramps result from loss of fluids and electrolytes
57
cholera is sensitive to ____, so large numbers of pathogenesis must be ingested
acid
58
cholera pathogenesis adheres to epithelial cells of ______, establish infection, produce cholera toxin, an A-B toxin
small intestine
59
B portion of cholera pathogenesis attaches to
receptors of microvilli
60
after cholera pathogenesis attaches to receptors of microvilli, what occurs?
A portion enters cells, activates a G protein that turns on adenylate cyclase to convert ATP to cAMP
61
high cAMP in cholera pathogenesis causes cell to secrete
chloride ions
62
what happens in cholera pathogenesis after chloride ions are secreted
sodium and other ions follow, and water follows the salts, yielding outpouring from cells
63
cholera pathogenesis toxin does not affect ____, but volume of fluid is too much to be absorbed, causing diarrhea
large intestine
64
cholera pathogenesis toxin encoded by ______: lysogenic conversion
bacteriophage
65
_____ is most common source for cholera
fecally contaminated water
66
foods including ________ are also causes for cholera
crab, oysters, vegetables
67
a person can discharge a ______ or more vibrio cholerae cells in each milliliter of feces
million
68
_____ can eliminate spread of cholera
effective wastewater treatment
69
_____ is the paradigm of "watery diarrhea"
cholera
70
rapid replacement of ______ and ______ given before damage to vital organs can occur (cholera)
fluids, electrolytes
71
intravenous or oral rehydration therapy can decrease mortality in cholera from over _____ to less than ____
30%, 1%
72
clean water and adequate sanitation are key control measures for
cholera
73
vaccines for cholera are available in many parts of world, however these do not induce _____
long-term immunity
74
in 2016, FDA approved ______ against serotype O1 intended for travelers to endemic areas; moderately effective in reducing incidence of watery diarrhea
live attenuated oral vaccine
75
signs and symptoms of shigellosis
dysentery, diarrhea (multiple low volume episodes a day), headache, vomiting, fever, stiff neck, convulsions, joint pain
76
______ is often fatal for infants in developing countries
shigellosis
77
incubation period of shigellosis
1-3 days
78
causative agents of shigellosis
gram-negative rods: s, dysenteriae, s.flexneri, s.boydii, s. sonnei
79
______ is the most virulent species of shigellosis
s. dysenteriae
80
_____ is the least virulent species of shigellosis
s. sonnei
81
______ and ______ are the most common species of shigellosis in developing countries
s. dysenteriae and s. flexneri
82
_______ causes over 2/3 of cases of shigellosis in U.S.
s. sonnei
83
_______ passes through the stomach, multiplies in the small intestine and migrates to the large bowl where it enters the epithelium
shigella
84
shigella taken up using antigen sampling function of _____
M cells
85
Shigella multiply inside ______, released at bases of epithelial cells after macrophages die
macrophages
86
shigella attach to specific receptors, inducing uptake by ______, multiply, cause actin polymerization to propel cell to cell
epithelial cells
87
shigella invasion results in death of _______, soughing of patches of epithelium; strong inflammatory response
epithelial cells
88
some strains of shigella produce ______, an A-B toxin responsible for hemolytic uremic syndrome
Shiga toxin
89
______ of shiga toxin binds to endothelial cells lining small blood vessels
B subunits
90
______ of shiga toxin halts protein synthesis, leading to cell death
A subunit
91
HUS may cause _____ and _______; often fatal
anemia, kidney failure
92
action of shiga toxin
the STX A subunit cleaves a specific adenine nucleoubase from the 28S RNA of the 60S subunit of the ribosome, thereby halting protein synthesis, and killing the target cell
93
shigellosis is transferred by
fecal-oral route
94
does shigellosis have a very low or very high infectious dose?
very low (10-100 organisms)
95
shigella is highly resistant to
stomach acid
96
shigella spreads rapidly in populations with
poor sanitation
97
some strains of shigella spread in
daycare facilities
98
some causes of shigellosis include
fecally contaminated food and water, anal intercourse
99
treatment and prevention of shigellosis
antimicrobials shorten duration; some strains are resistant
sanitary measures control spread
100
signs and symptoms of escherichia coli gastroenteritis
depends on the strain; some cause watery diarrhea, others cause a shigellosis-like dysentery
one group causes hemolytic uremic syndrome (HUS)
101
causative agent of escherichia coli gastroenteritis
escherichia coli
102
is escherichia coli gastroenteritis gram negative rod, or gram positive rod?
gram negative rod
103
escherichia coli gastroenteritis is closely related to ______
shigella
104
unlike shigella, most strains of escherichia coli ferment _______
lactose
105
_____ strains food borne; colonize large intestine; epidemics have involved ground beef, unpasteurized milk, bean sprouts, leafy vegetable, others
STEC
106
____ of patients with STEC strain develop Hemolytic Uremic Syndrome-can be fatal
roughly 10%
107
_____ strains cause diarrhea in infants in developing countries, also visitors; relatively high infectious dose; "travelers diarrhea"
ETEC
108
_____ primarily cause disease in young children in developing countries; not easily spread by direct contact
EIEC
109
______ strains important in infants; antibodies in breast milk protective; relatively low infectious dose
EPEC
110
_____ strains infect children, travelers, AIDS patients
EAEC
111
______ strains have caused outbreaks in children
DAEC
112
characteristic features of e.coli DAEC strain
Grows as a diffuse layer in a thick mucus-associated biofilm on the intestinal epithelium; produces toxins
113
characteristic features of e.coli EAEC strain
Grows in brick-like aggregations in a thick mucus-associated biofilm on the intestinal epithelium; produces toxins
114
characteristic features of e.coli EIEC strain
nvades the intestinal epithelium, causing a disease, very similar to shigellosis
115
characteristic features of e.coli EPEC strain
colonizes the small intestine; induces changes in actin filaments, causing the microvilli to be replaced by pedestals under the bacterial cells (A/E lesions)
116
characteristic features of e.coli ETEC strain
Colonizes the small intestine and produces toxins, one nearly identical to cholera toxin
116
characteristic features of e.coli STEC strain (shiga toxin)
Same as EPEC, except it produces Shiga toxin and colonizes the large intestine rather than the small intestine
117
symptoms of e.coli DAEC strain
diarrhea, particularly in children
118
symptoms of e.coli EAEC strain
variable symptoms; nausea, watery diarrhea (both acute and persistent)
119
symptoms of e.coli EIEC strain
fever, cramps, diarrhea containing blood and pus
120
symptoms of e.coli EPEC strain
fever, vomiting, watery diarrhea containing mucus
121
symptoms of e.coli ETEC strain
nausea, vomiting, abdominal cramps, massive watery diarrhea leading to dehydration
122
symptoms of shiga toxin producing e.coli (STEC)
Fever, abdominal cramps, bloody diarrhea
without pus; some patients develop hemolytic
uremic syndrome; most strains identified in
outbreaks are serotype O157:H7
123
treatment and prevention of escherichia coli gastroenteritis
replacement of lost fluid, antibiotics not routinely used since most cases are self-limiting, hand washing, pasteurization of drinks, cooking of food
124
widespread use of ______ to prevent diarrhea has promoted development of resistant strains of e.coli
antibiotics
125
incubation period of escherichia coli gastroenteritis
2 hours to 6 days
126
how many cases are there in the US of salmonella gastroenteritis a year?
1.2 million
127
most salmonella gastroenteritis outbreaks are due to
foods: meat, milk, eggs, etc.
128
signs and symptoms of salmonella gastroenteritis
diarrhea, abdominal cramps, nausea, vomiting, headache, fever
129
salmonella gastroenteritis is often ______ and ____ depending on strain and dose
short-lived and mild
130
incubation period of salmonella gastroenteritis
12 hours to 3 days
131
causative agent of salmonella gastroenteritis
salmonella enterica
132
bacterial characteristics of salmonella enterica
gram-negative rod; member of the neterobacteriaceae family
133
there are more than ______ serotypes of salmonella gastroenteritis based on somatic (O), flagellar (H), and capsular (K) antigens
2,400
134
pathogenesis of salmonella gastroenteritis
most are sensitive to acid, so requires a high infectious dose (about 10^6 bacteria)
135
salmonella enterica attach to epithelial cells of distal _______; effector proteins via type III secretion system induce _______
small intestine, endocytosis
136
inflammatory response of salmonella gastroenteritis causes
diarrhea
137
inflammation of salmonella gastroenteritis also produces ______ that salmonella can use in anaerobic respiration
tetrathionate
138
most cases of salmonella gastroenteritis come from
nonhuman animal sources
139
bacteria of salmonella gastroenteritis can survive for months in
soil and water (untreated manure can spread)
140
______ is typically the source of contaminated food products (especially poultry) in salmonella gastroenteritis cases
manure fertilizer
141
children commonly infected with salmonella gastroenteritis by handling
pet reptiles
142
treatment and prevention of salmonella gastroenteritis
most recover without antibiotics; many strains are antibiotic resistant
sanitary handling of food (cook to 160 degrees fahrenheit)
143
systemic diseases that originate in the intestine
enteric fevers
144
typhoid and paratyphoid fevers signs and symptoms
progressively increasing fever over a number of days, severe headache, constipation, abdominal pain
in severe cases; intestinal rupture, bleeding, shock, death
145
incubation period of typhoid and paratyphoid fevers
1-4 weeks
146
causative agent of typhoid fever
salmonella serotype Typhi
147
causative agent of paratyphoid fever
salmonella serotype paratyphi
148
typhoid and paratyphoid fevers are confirmed by
blood culture
149
systemic infection of typhoid and paratyphoid fevers causes
fever, abscesses, sepsis, and shock, often with little or no diarrhea
150
in typhoid and paratyphoid fevers, ______ sometimes destroyed, leading to rupture of intestine, hemorrhage, and death
Peter's patches
151
typhoid and paratyphoid fevers toxins produced when cells are
within a host cell
152
_______ caused by bacteria that colonize intestines, cross mucous membrane via M cells, multiply within macrophages, and are carried in bloodstream throughout the body
enteric fevers
153
______ are the only known host of typhoid and paratyphoid fevers
humans (so it spreads person to person often via contaminated food or water)
154
some survivors of typhoid and paratyphoid fevers remain colonized in _______; can shed high numbers for years
gallbladder
155
treatment and prevention of typhoid and paratyphoid fevers
antibiotics; some strains are resistant
surgical removal of gallbladder and months of antibiotic therapy often necessary to rid carriers of infection
156
two vaccines against salmonella typhi, each approximately ______ effective; attenuated live oral or injectable capsular polysaccharide
50-75%
157
there is no vaccine against _______
salmonella paratyphi
158
incubation period of campylobacteriosis
1-11 days, usually 2-5 days
159
most common form of bacterial gastroenteritis is
campylobacteriosis
160
symptoms of campylobacteriosis
fever, vomiting, diarrhea, abdominal cramps, dysentery in about half the cases
161
causative agent of campylobacteriosis
campylobacter jejuni
162
bacterial characteristics of campylobacter jejuni
curved, gram-negative rod first isolated in 1972
can be cultivated under microaerophilic conditions with a selective medium
163
______ penetrates epithelial cells of small and large intestines, cause localized inflammatory reaction
campylobacter jejuni
164
up to 40% of ______ cases preceded by campylobacteriosis; automimmunity is likely involved
Gullian-barre syndrome (reversible partial paralysis)
165
estimated 1.3 million cases and approximately 100 deaths/year in US for _______, most in elderly or immunodeficient
campylobacteriosis
166
numerous ____ and ______ outbreaks reported for campylobacteriosis, although most cases are sporadic
foodborne, waterborne
167
_______ lives in intestines of domestic animals
c jejuni
168
poultry is the most common source of infection for _______, with up to 90% containing it
campylobacteriosis
169
campylobacteriosis has a _____ infectious dose
low (approximately 500 organisms)
170
treatment of campylobacteriosis
typically self-limiting, leaves patient immune
antibiotics used for severe cases
171
prevention of campylobacteriosis
cooking and proper handling of raw poultry
hand washing after animal feces contact
keeping outdoor areas free of bird droppings
chlorinating drinking water pasteurizing beverages
172
clostridioides difficile infection (CDI) is
antibiotic-associated diarrhea, increasing in incidence and severity since early 2000s
173
signs and symptoms of clostridioides difficile infection (CDI)
rashes widely in severity, mild cases characterized w fever, pain beginning less than a week after infection
more serious cases progress to colitis, sometimes with pseudomembranes
severe cases can be life threatening
174
causative agent of clostridioides difficile infection (CDI)
clostridioides difficile (c.diff)
175
bacterial characteristics of clostridioides difficile
gram-positive, obligate anaerobic rod
176
c. diff forms _____ highly resistant to disinfectants, environmental conditions, so control is difficult
endospores
177
ingested endospores of clostridioides difficile infection (CDI) develop into ______ that sometimes colonize large intestine
vegetative cells
178
there are _____ of clostridioides difficile infection (CDI), differ in pathogenicity
many strains
179
strains causing CDI produce ______; hyper virulent strains increasing in prevalence
toxins
180
clostridioides difficile infection (CDI) is resistant to
fluoroquinolones
181
CDC considers C. diff an
urgent health threat
182
_______ due to antibiotic use allows proliferation of C. difficile
dysbiosis (microbial imbalance)
183
two toxins of clostridioides difficile infection (CDI) (ToxA and ToxB) are lethal to
intestinal epithelium
184
toxins of clostridioides difficile infection (CDI) disrupt _____ and induce ______
host cell actin polymerization, strong inflammatory response
185
binary toxin of clostridioides difficile infection (CDI) produced by ______; interferes with host actin polymerization
hypervirulent strains
186
clostridioides difficile infection (CDI) is primarily in _________
hospitalized patients on antibiotic therapy
187
C. difficile can grow to high numbers when ______ is disrupted
normal microbiota
188
infectious endospores of clostridioides difficile infection (CDI) are shed in
feces
189
common antibiotics used in clostridioides difficile infection (CDI)
nacomycin, metronidazole, or fidaxomicin
190
in which disease may it be beneficial to stop antibiotics because symptoms often disappear?
clostridioides difficile infection (CDI)
191
fecal microbiota transplant (FMT) repairs _____
dysbiosis (stool replacement therapy)
192
preventive measures for clostridioides difficile infection (CDI)
minimizing use of antibiotics, hand washing, wearing gloves, disinfectants
193
rotavirus gastroenteritis is the _______ gastroenteritis around the world in infants and children
most viral
194
signs and symptoms of rotavirus gastroenteritis
abrupt vomiting, slight fever, followed shortly by produce watery diarrhea
195
incubation period of rotavirus gastroenteritis
24-48 hours, usually clear within a week, but fatal dehydration can occur if fluids are not replaced
196
causative agent of rotavirus gastroenteritis
rotaviruses
197
bacterial characteristics of rotaviruses
Non-enveloped with double-walled capsid and double-stranded segmented RNA genome (11 segments)
Major subgroup of Reoviridae
198
rotavirus gastroenteritis damages lining of _____; less fluid is absorbed
upper small intestine
199
in rotavirus gastroenteritis, viral protein acts as
enterotoxin
200
rotavirus gastroenteritis is transmitted via
fecal-oral route
201
if not vacccinated, most children before the age of are infected with
rotavirus gastroenteritis
202
infection of rotavirus gastroenteritis yields
some immunity (later infections are milder)
203
rotavirus gastroenteritis is about 25% of
travelers diarrhea
204
_______ Infects variety of other animals; most do not also infect humans, but genetic re-assortment could occur
rotavirus gastroenteritis
205
are there specific diagnostic measures taken for rotavirus gastroenteritis?
No, positive diagnosis does not change treatment regimen; therefore its not typically done
206
treatment of rotavirus gastroenteritis
no direct treatment, infants and small children are sometimes hospitalized and given intravenous fluids
207
prevention of rotavirus gastroenteritis
handwashing, disinfectant use, other sanitary measures
attenuated vaccines administered to infants result in substantial decline in incidence
208
most common cause of viral gastroenteritis in US with about 21 million cases annually
norovirus gastroenteritis
209
norovirus gastroenteritis is a ______ agent due to easy spread and rapid and severe debilitation of patients
class B bioterrorism
210
signs and symptoms of norovirus gastroenteritis
abrupt onset of nausea, vomiting (more severe in older children and adults), watery diarrhea
211
incubation period of norovirus gastroenteritis
1-2 days
212
causative agent of norovirus gastroenteritis
noroviruses
213
bacterial characteristics of noroviruses
non-enveloped, single-stranded RNA viruses in Caliciviridae
214
new strains of ______ frequently emerge
noroviruses
215
_______ infect epithelium of upper smaller intestine, causing cell death and decreased production of digestive enzyme
norovirus gastroenteritis
216
epithelium of norovirus gastroenteritis recovers fully within about
2 weeks
217
natural immunity of norovirus gastroenteritis is
short-lived
218
transmission of norovirus gastroenteritis
primarily fecal-oral, but also via aerosols and contaimined surfaces
219
norovirus gastroenteritis is highly contagious, infectious dose of
fewer than 20 virions
220
visions of norovirus gastroenteritis resists ______, stable in environment
destruction
221
epidemics of norovirus gastroenteritis common on
cruise ships, dormitories, military barracks
222
more than 50% of food borne disease outbreaks due to
norovirus
223
_______ established in 2009 to trace strains of norovirus
CaliciNet
224
treatment of norovirus gastroenteritis
no proven medications, no vaccine
225
prevention of norovirus gastroenteritis
handwashing w soap and water
disinfectants, other sanitary measures
infected food worked should be restricted from working for 72 hours after symptoms subside
