Brainscape's Knowledge GenomeTM

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


See full index

CSIM 1: Microbiology Strand > CSIM 1.54: Major Bacteria Producing Gastroenteritis > Flashcards

CSIM 1.54: Major Bacteria Producing Gastroenteritis Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is gastroenteritis?

A

Inflammation of the stomach and intestines

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

What parasitic causes of GI illness exist?

A
  • Protozoa

* Helminths

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

What are the common bacterial causes of gastroenteritis?

A
  • Salmonella
    • E. coli
    • Shigella
    • Clostridium difficile
    • Campylobacter
    • S. aureus
    • Vibrio cholerae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the host-related factors which control whether someone is likely to get bacterial gastroenteritis?

A
  • Age
    • Immune factors (e.g. IgA levels)
    • Host receptors for microbial toxins
    • Host receptors for microbial adhesion
    • Intestinal motility
    • Nutritional status
    • Gastric acidity
    • GI flora competition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What foods most frequently contain bacteria capable of causing gastroenteritis?

A
  • Dairy products
    • Eggs
    • Meat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the pathogenic process of bacterial gastroenteritis

A

1) Bacteria escape the gastric acidity
2) Adhesion to the intestinal receptors allows establishment, multiplication and competition with existing gut flora
3) • Here, some bacteria invade into epithelial cells and submucosa towards lymph nodes causing abdominal pain
• Some bacteria invade the bloodstream, causing fever and systemic illness
• All bacteria produce toxins, which can lead to diarrhoea and vomiting

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

What is a coliform and which bacterial causative agents of gastroenteritis can be described as coliforms?

A

Rod-shaped, gram-negative bacteria:
• E. coli
• Salmonella enterica
• Shigella

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

In terms of gastroenteritis, what do the following do?

1) Enterotoxins
2) Cytotoxins

A

1) A toxin which leads to fluid secretion without mucosal damage (–> diarrhoea)
2) Mucosal damage causing dysentry (blood in stools)

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

What is food poisoning?

A

A lay term referring to gastroenteritis caused by contamination by:
• Bacteria
• Bacterial toxins

NB: BACTERIA DONT HAVE TO BE PRESENT, toxins are enough to cause food poisoning

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

What are the two prominent serotypes of Salmonella enterica? How many serotypes are there?

A
  • Typhimurium
    • Enteritidis

2000 serotypes

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

What does Salmonella enterica typhimurium do? What is the incubation period for this?

A

Invades the bloodstream from the gut, causing typhoid (fever with an eruption of red spots on the chest and abdomen and severe intestinal irritation)
• 10-14 days incubation (invasion after first week

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

How long does salmonella food poisoning take to take affect?

A

Incubation period: 8-48 hours

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

What is the most common cause of dysentry in the UK?

A

Bacillary dysentry by the four Shigella species releasing CYTOTOXINS

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

How many species of Shigella are there?

A 
four:
  •  S. dysentriae
  •  S. flexneri
  •  S. boydii
  •  S. sonnei
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is E. coli serotyped

A 
Based on:
  •  Lipopolysaccharide antigen (LBS
  •  Somatic antigen (O) 
  •  Flagella antigen (F) 
  •  Capsular antigen (K)

E.g.: O157:H7

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

How does E. coli gastroenteritis often present?

A

Bloody diarrhoea (dysentry) due to cytotoxin release

17
Q

What is ‘rice water diarrhoea’ and what causes it? What are the other symptoms?

What pathogenesis causes these symptoms?

A

Completely white diarrhoea, caused by Vibrio cholerae
• Vomiting
• Hypovolumic shock
• Muscle cramps
• Death in 12-24 hours without treatment

Penetration of the mucous later of gut and release of cholera toxin 01
• Causes excessive loss of water and electrolytes from the gut
• Overproduction of cAMP causing reduced uptake of NaCl and increased secretion of bicarbonate and chloride ions

18
Q

Describe Vibrio genus:
• Gram
• Motility
• Shape

A
  • Gram-negative
    • Motile
    • Curved rods
19
Q

How is cholera treated?

A
  • Fast rehydration therapy
    • Oral rehydration therapy
    • Antibiotics
20
Q

Which antibiotics are effective in the treatment of cholera?

A
  • Tetracycline
    • Chloramphenicol
    • Co-trimoxazole
21
Q

What is the main source of infection of Campylobacter?

A

animals (60% chickens)

22
Q

Is Campylobacter often a source of food poisoning? Why?

A

No - does not multiply in foods as it is fragile

23
Q 
Describe the genus Clostriudium
  •  Gram
  •  Shape
  •  Aerobicity 
  •  Spores

What are the predominant species of Clostridium?

A
  • Gram positive
    • Bacilli
    • Anaerobes
    • Spore forming

Clostridium:
• C. difficile
• C. perfringens
• C. sporogenes

24
Q

Describe how Clostridium perfringens often causes infection

What are the symptoms of C. perfringens?

A
  • Creates heat-resistant spores, which are difficult to cook in bulk cooking
    • Spores germinate and multiply when food is consumed
    • The bacteria release endotoxin

Fever, D&V

25
Q

What is the cause of antibiotic-associated bacteria? Describe what this means

What does this bacterium produce?

How is this treated?

A

C. difficile:
• Antibiotics disrupt the gut flora
• This allows C. diff an opportunity to proliferate with little competition

Two enterotoxins:
• Enterotoxin A
• Enterotoxin B

Treated with:
• Oral/IV metronidazole
• Oral vancomycin

26
Q 
Describe the pathogenesis of S. aureus gastroenteritis, including:
  •  Transmission
  •  Toxin
  •  Incubation
  •  Symptoms
  •  Resolution
A
  • Food-bourne
    • Enterotoxin B-mediated
    • 2-4 hour incubation
    • Violent vomiting and then profuse diarrhoea
    • Self-limiting within 24 hours
27
Q

Which bacterium causes fried rice food poisoning? Gram and shape?

A

Bacillus cereus. Gram positive bacilli.

28
Q

Which antibiotics are overall used for severe gastrointestinal infection?

A
  • Ciprofloxacin
    • Azithromycin
    • Doxycycline
    • Metronidazole
29
Q

How is rehydration achieved?

A
  • Oral rehydration solution

* IV Ringer’s lactate

CSIM 1: Microbiology Strand (18 decks)

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