Bacterial and Viral GI Infections (Quiz 2) Flashcards

1
Q

what feature of GI bacteria allows them to live in the stomach and survive stomach acid

A
  • those without envelopes (have sturdy capsids)
  • secretion of enzymes to buffer pH (H. pylori & urease)
  • inherent acid resistance (Shigella spp.)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how does bacterial overgrowth syndrome occur

symptoms it can cause

A
  • decrease amount of acidity in the stomach
  • increase number of microbes
  • grow further into the stomach/small intestine
  • vitamin deficiencies
  • fat malabsorption
  • malnutrition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

which classification of enteric bacterial pathogens is caused by facultative intracellular pathogens and relies on invasion of host cells

examples and gram stain

A
  • enteroinvasive
  • Salmonella enterica (gram -)
  • Shigella (gram -)
  • Yersinia enterocolitica
  • Campylobacter jejuni (gram -)
  • Listeria monocytogenes (gram +)
  • Enteroinvasive E. coli

ENTEROINVASIVE BACTERIA ARE CLESSY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

which classification of enteric bacterial pathogens is caused by bacteria that produce enterotoxin and invasion does NOT play a role in disease

examples and gram stain

A
  • Enterotoxic
  • Vibrio cholerae (gram -)
  • ETEC
  • C. diff

VEC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

which classification of enteric bacterial pathogens is caused by bacteria that destroy epithelium and invasion does NOT play a role in disease

example and gram stain

A
  • Enteropathogenic
  • EPEC (gram -)
  • EHEC (gram -)
  • H. pylori

HEE!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

which classification of enteric bacterial pathogens does invasion play a role in disease

A
  • Enteroinvasive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

rice water stool associated with which bugs

A
  • V. cholerae, ETEC

they secrete bacterial toxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Typhoid group of Salmonella enterica affects what species

what about nontyphoid salmonella enterica

A
  • humans only

- animals and humans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Salmonella enterica serovar typhi is a _________ pathogen

states of typhoid fever

where does it colonize?

describe its infection

A
  • obligate human
  • carrier state with shedding of bacteria
  • biliary duct
  • starts out as GI infection and disseminates to other organs in a systemic infection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

infectious dose of S. enterica typhoid variant

what about non-typhoid

A
  • low

- high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

are antibiotics recommended as treatment for S. enterica typhi

which ones?

what about non-typhoid variants

A
  • yes
  • Ciprofloxacin or Ceftriaxone
  • no
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

where does Shigella colonize
how?

motility patterns of Shigella spp

any animal reservoirs?

how is it transmitted

treatment

A
  • lower intestine of humans
  • acid resistant
  • nonmotile
  • no animal reservoirs
  • person-person
  • rehydration +/- Antbiotics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

where would you find:

S. sonnei
S. flexneri
S. dysenteriae

A
  • US and developed world
  • developing world
  • epidemics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

why do we generally not give people with shigellosis antibiotics

which antibiotic

A
  • can cause hemolytic uremic syndrome

- ciprofloxacin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Shiga toxin of S. dysenteriae and EHEC

where is its G3b receptor expressed

A
  • A+B toxin
  • blocks absorption of glucose, electrolytes, and amino acids
  • associated with development of HUS
  • endothelial cells of intestine, kidney, and brain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

C. jejuni requires what kind of agar to grow

A
  • charcoal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the most common bacterial cause of diarrheal disease in the US

shape

what is its infectious dose

treatment

A
  • Campylobacter
  • cork-screw rod
  • low infectious dose
  • rehydration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

which bacteria grows at refrigerator temp

hosts

treatment for invasive infections

A
  • Listeria monocytogenes
  • range of hosts, humans, birds, fish
  • IV antibiotics (ampicillin and gentamicin) for 14-21 days
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

motility pattern of L. monocytogenes

A
  • actin-based

- propels from one cell to another using host actin so it doesn’t have to enter extracellular environment

20
Q

how Listeria is spread

common objects?

A
  • foodborne
  • mother-child
  • dairy
  • processed meats
21
Q

what population do we worry about with listeria

why

A
  • pregnant women
  • they may have mild flu-like symptoms but can cause series defects for their baby like miscarriages, stillbirth, and pre-term labor
  • can also cause CNS infection in neonates
22
Q

where do you normally find Vibrio in the environment

any infected animal hosts?

important shape of vibrio

transmission by

A
  • fresh, brackish or marine water
  • on shells of crustaceans
  • no (humans only)
  • comma-shaped rod
  • contaminated water or food
23
Q

how do cholera toxin and ETEC labile toxin work

A
  • A+B toxin

- activates adenylate cyclase which results in secretion of electrolytes and water resulting in profuse, watery diarrhea

24
Q

what do Enterotoxigenic E. coli do

A
  • deliver enterotoxin
25
Q

what do Enteropathogenic E. coli do

A
  • adhere to and damage epithelium, but don’t invade
26
Q

what do Enteroinvasive E. coli do

A
  • invade, escape phagosome, and spread to adjacent cells
27
Q

what do Enterohemorrhagic E. coli do

A
  • deliver shiga toxin
28
Q

what enteric viruses has

dsRNA, segmented

dsDNA virus

ss+RNA viruses

A
  • rotavirus
  • adenovirus
  • norovirus
  • astrovirus
  • enteroviruses
29
Q

how do enteric viruses differ from enteroviruses

A
  • with enteroviruses, infection and disease occurs in other sites after GI replication
30
Q

what are the enteric viruses

A
  • rotavirus
  • norovirus
  • astrovirus
  • adenovirus
31
Q

what are the enteroviruses

A
  • poliovirus
  • coxsackievirus
  • hepatitis A
32
Q

which virus has a viral protein that acts like an enterotoxin

what viral protein

what does it do

A
  • rotavirus
  • NSP4
  • affects Ca2+ flux in uninfected enterocytes
33
Q

Rotavirus mostly affects what age group

A
  • 6 mo - 2 years
34
Q

seasonal epidemic of rotavirus

A
  • fall - SW

- spring - NE

35
Q

treatment of rotavirus

A
  • rehydration
36
Q

is there a vaccine for rotavirus?

which ones?

A
  • yes, there are two
  • Rotarix
  • RotaTeq
37
Q

which virus is the most common cause of viral gastroenteritis in adults and adolescents

what part of the body does it infect

treatment

A
  • norovirus
  • villi in jejunum
  • rehydration
38
Q

importance of poliovirus

A
  • can cause poliomyelitis - inflammatory disease of gray matter in spinal cord
39
Q

which polio vaccine is the inactivated vaccine

what kind of antibody response does it generate?

what does it protect against

A
  • Salk
  • IgG; no IgA induced
  • paralytic polio
40
Q

which polio vaccine is the oral polio live vaccine virus

what antibodies does it stimulate

do we use it in the US? Why?

A
  • Sabin
  • oral and duodenal IgA, serum IgG
  • why? Can mutate back to neurovirulence
41
Q

what does Coxsackie virus cause

A
  • hand-foot-mouth disease
42
Q

non-polio enterovirus infections are generally during which seasons

where are they normally found

A
  • summer to fall

- water supplies

43
Q

two types of damage for enteric GI pathogens

A
  • inflammatory

- secretory diarrhea

44
Q

what bacteria will grow on Lactose MacConkey agar

A
  • gram negatives
45
Q

how does Salmonella enterica survive gastric passage

A
  • acid-tolerant
46
Q

Salmonella enterica affects what species

Salmonella bongori affects what species

A
  • mammals and reptiles

- replies only

47
Q

which virus are outbreaks more common in infants or elderly

A
  • astrovirus