Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Bacteriology > Salmonella, Shigella Campylobacter, Helicobacter, Yersinia > Flashcards

Salmonella, Shigella Campylobacter, Helicobacter, Yersinia Flashcards

1
Q

What is a way that many people have been contracting Salmonella recently?

A

Backyard poultry flocks

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

What two organisms cause the most foodborne outbreaks?

A

Salmonella and Campylobacter

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

Which species of Salmonella has Vi capsule?

A

S. Typhi

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

What is the clinical presentation of Non-typhoid Salmonella (NTS)?

A

Typical gastroenteritis
Diarrhea
Caused by many serotypes

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

What is the clinical presentation of typhoid Salmonella?

A 
Systemic syndrome (malaise, headache, cough, etc.)
Enteric fever
Rose spots
Hepatosplenomegaly
Caused by S. Typhi and S. parathyphi
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do you treat Typhoid v. non-Typhoid Salmonella?

A

Typhoid - antibiotics

Non-typhoid - no antibiotics

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

What are the reservoirs for Typhoid v. non-Typhoid Salmonella?

A

Typhoid - only humans

Non-typhoid - animals

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

What is the mechanism by which people are carriers of S. Typhi?

A

S. typhi gets associated with gall stones (biofilm)

Can have asymptomatic excretion from gallbladder colonization

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

What is a major complication of S. Typhi infection?

A

Intestinal hemorrhage and perforation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the virulence factors of Salmonella?

A

Pathogenicity islands
Two Type III secretion systems:
- One allows bacteria into cell (affects actin)
- Second ejects effectors into cytosol and prevents lysosomal fusion
Can then multiply in vacuole

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

How does host response differ from Typhoidal v. non-typhoidal salmonella?

A

Typhoidal - minimal intestinal inflammation, not many neutrophils
Non-typhoidal - lots of inflammation, lots of neutrophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the purpose of the Vi capsule in S. Typhi?

A

Prevents immune system from recognizing TLR4 (with capsule, TLR4 cannot bind LPS on bacterial surface)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does Typhoidal Salmonella prevent inflammatory response?

A

Capsule, evades TLR4

Downregulation of flagellin gene, evades TLR5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is the inflammation produced in non-typhoidal salmonella beneficial?

A

Expresses Salmochelin and can use tetrathionate

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

What is the mechanism of salmochelin?

A

In response to inflammation, host produces lipocalin, that binds siderophores produced by other enteric bacteria like E. Coli. Siderophores bring iron to the bacteria, so lipocalin binding to siderophores = no iron. Salmonella produces salmochelin (it’s own siderophore) that cannot be bound by lipocalin, so more iron for Salmonella = advantage over other gut microbes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the morphology of Salmonella?

A

Gram neg rod

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

What is the morphology of Shigella?

A

Gram neg rod

18
Q

What is the most common Shigella species in the US?

A

Shigella sonnei

19
Q

What is the most common Shigella species worldwide?

A

Shigella flexneri

20
Q

What is the reservoir for Shigella?

A

Humans only (no animal reservoir), transmitted person to person

21
Q

Is the infectious dose of Shigella large or small?

A

Very small! Similar to EHEC

22
Q

What are characteristics of dysentery?

A

Scanty stools of blood and mucus
Tenesmus
Abdominal cramps
Many fecal leukocytes on microscopy

23
Q

What are major complications of Shigella?

A

Severe Colitis
Persistent diarrhea and dehydration
Rectal prolapse
Reactive arthritis

24
Q

Does Salmonella affect large or small bowel?

A

Small

25
Q

Does Shigella affect large or small bowel?

A

Large

26
Q

What is the pathogenesis of Shigella?

A

Invades M cells using Type III secretion system
Propel from basolateral side (unique) into cytoplasm, rockets through lateral membranes from one cell through to the other
Does this using nucleation of the actin cytoskeleton behind one pole.

27
Q

What are the virulence factors of Shigella?

A

Virulence plasmid containing genes for Type III secretion system, effectors, enterotoxins

28
Q

What makes Shigella dysenteriae the most virulent and infectious?

A

Secretes Shiga toxin

29
Q

What other organism expresses Shiga toxin besides Shigella dysenteriae?

A

EHEC (Enterohemorrhagic E. Coli)

30
Q

What are the two species of Yersinia that cause gastroenteritis?

A

Y. enterocolitica
Y. pseudotuberculosis
(NOT Y. pestis)

31
Q

What is the pathogenesis of Yersinia?

A

Enters M cells
Injects effectors via Type III secretion system (resists phagocytosis, downregulates inflammation)
Colonizes Peyers patches and mesenteric lymph nodes

32
Q

What food is Campylobacter associated with?

A

Raw milk

33
Q

How do Campylobacter appear on culture?

A

Curved gram negative (sea gull)
Microaerophilic
Flagellated

34
Q

What is the clinical presentation of Campylobacter?

A

Causes inflammatory diarrhea much like Non typhoidal salmonella and Shigella

35
Q

When should antibiotics be used for Campylobacter?

A

Very early in the infection, otherwise ineffective

36
Q

What is a complication of Campylobacter?

A

Guillain-Barre syndrome

37
Q

What is the pathogenesis of Guillain-Barre syndrome?

A

Lipooligosaccharides (LOS) on outside of Campylobacter look similar to nerve gangliosides. Immune system makes antibodies to the LOS, end up cross-reacting with the gangliosides

38
Q

What makes Helicobacter pylori unique?

A

Pathogen of the stomach

39
Q

What is the clinical presentation of H. pylori?

A

Can by asymptomatic!
Gastritis
Duodenal Ulcers
Gastric carcinoma

40
Q

What is the key virulence factor of H. pylori?

A

Urease

Allows H. pylori to neutralize low pH of stomach and then attach and invade gastric mucosa.

41
Q

What is the treatment for H. pylori?

A

Triple drug therapy

Bacteriology (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions