Brainscape's Knowledge GenomeTM

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


See full index

MCDone > Community Acquired Bacterial Infections > Flashcards

Community Acquired Bacterial Infections Flashcards

1
Q

Define virulence factor.

A

Molecules produced by pathogens that contribute to the pathogenicity of the organism

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

List some common bacterial virulence factors and include their function.

A

Flagella – movement and attachment
Pili – adherence factors
Capsule – protects against phagocytosis
Endospores – metabolically dormant forms of bacteria – they are heat, cold, desiccation and chemical resistant
Biofilms – organised aggregates of bacteria embedded in a polysaccharide matrix – antibiotic resistant

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

Give examples of bacteria that have capsules

A

S. pneumoniae

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

What are exotoxins?

A

A toxin released by a living bacterial cell into its surrounding

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

What are the five different types of exotoxin?

A 
Neurotoxins 
Enterotoxins 
Pyrogenic toxins  
Tissue invasive toxins  
Miscellaneous
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an endotoxin?

A

This is the lipid A part of lipopolysaccharide that is found on the outer membrane of Gram-negative cells

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

Why can treating patients with Gram-negative infection sometimes worsen their condition?

A

Antibiotics can cause lysis of the bacteria meaning that the endotoxins are released into the circulation in large quantities
This can trigger an immune response that leads to SEPTIC SHOCK

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

What is an outbreak?

A

A greater than normal or greater than expected number of individuals infected or diagnosed with a particular infection in a given time period, or a particular place, or both

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

How can an outbreak be identified?

A

Surveillance

Good and timely reporting systems are necessary

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

What was the 2011 E. coli outbreak in Germany caused by?

A

Enteroaggregative shiga toxin producing E. coli

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

What were the symptoms of Shiga Ecoli bacterium?

A

Gastroenteritis

Haemolytic uraemia syndrome (acute renal failure + haemolytic anaemia + thrombocytopenia)

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

What was special about the bacterial strain that caused by outbreak?

A

The bacterial strain was an enteroaggregative E. coli strain (EAEC) that had acquired the ability to produce shiga toxin (through phagetransfer)
Shiga toxin production is a feature of Enterohaemorrhagic E. coli(EHEC)
This produced a new strain called Enteroaggregative haemorrhagic E. coli (EAHEC

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

Describe the structure of shiga toxin.

A

There is an A subunit that is non-covalently associated with a pentamer of protein B

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

Describe the action of shiga toxin.

A

Subunit A is the enzymatically active domain
Subunit B is responsible for binding to the host cell membrane
Subunit A cleaves 28S ribosomal RNA in eukaryotic cells thus inhibiting protein synthesis
Bacterial ribosomes are also a substrate for subunit A so it can lead to decreased proliferation of susceptible bacteria (e.g. commensal microflora of the gut)

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

How was the shiga toxin gene transferred between bacteria?

A

Bacteriophage

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

What is the important virulence factor in EAEC?

A

Aggregative adherence fimbriae (AAF) – this is required for adhesion to enterocytes

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

What type of bacterium is Legionella pneumophila and what is the route of infection?

A

Gram negative

It is transmitted through inhalation of contaminated aerosols

18
Q

Which cells within the human host does L. pneumophila infect and grow inside?

A

Alveolar macrophages

19
Q

What is the important virulence factor for L. pneumophila?

A

Type IV secretion system

20
Q

What feature of Mycobacterium tuberculosis makes it more difficult to treat?

A

It has a mycolic acid outer membrane – this prevents normal antibiotics from getting into the cell- note is gram positive

21
Q

State three bacterial sexually transmitted diseases including the species of bacteria that cause the diseases.

A

Chlamydia - Chlamydia trachomatis
Syphilis –Treponema pallidum
Gonorrhoea –Neisseria gonorrhoeae

22
Q

What is a major consequence of Chlamydia in the developing world?

A

Blindness (due to eye infection)

23
Q

How does N. gonorrhoeae establish infection in the urogenital tract?

A

It interacts with non-ciliated epithelial cells

24
Q

What are the important virulence factors of N. gonorrhoeae?

A

Pili

Antigenic variation escapes detection and clearance by the immune system

25
Q

What is the most commonly reported infectious GI disease in theEU?

A

Campylobacter jejuni

26
Q

What is the route of infection of Campylobacter and Salmonella?

A

Ingestion of undercooked poultry

27
Q

State some important virulence factors of Campylobacter jejuni.

A

Adhesion and invasion factors
Type IV secretion system
Toxin

28
Q

Which subset of the population has the highest incidence of Salmonella and Campylobacter infection?

A

Young children (0-4 years)

29
Q

What is an important virulence determinant of Salmonella sp.?

A

Type III secretion system

NOTE: Salmonella sp. can cause outbreaks whereas Campylobactertends to be sporadic cases

30
Q

What are the important virulence factors of Vibrio cholerae?

A

Cholera toxin

Type IV fimbria

31
Q

Explain how cholera toxin works.

A

It has A and B subunits
A is the active toxin
B allows entry of the toxin into the epithelial cell
The A subunit activates adenylate cyclase, thus increasing the production of cAMP
The cAMP then binds to CFTR and causes Cl- efflux
Water follows the ion movement so you get massive movement of water into the lumen of the intestine

32
Q

Give bacteria that have endospores

A

Bacillus sp.

Clostridium sp.

33
Q

Give bacteria that have biofilms

A

P. aeruginosa

S. epidermidis

34
Q

Bacteria producing neurotoxins

A

Tetanus

Botulinum

35
Q

Bacteria producing enterotoxins-> diarrorhoea

A

Cholera
E-coli
Shigella

36
Q

Bacterai producing enterotoxins-> food poisoning

A

Bacilus cereus

Staph A

37
Q

What are pyrogenic etotoxins

A

Stimulate release of cytokines

38
Q

Bacteria producing pyrogenic etotoxins

A

Staph aureus

Strep pyogenes

39
Q

What do tissue invasion etotoxins do

A

Allow bacteria to destroy and tunnel through tissue - destroy collagen, blood cells, DNA or fibrin eg

40
Q

Bacteria producing tissue invasion etotoxins

A

Staph aureus
Strep pyogenes
Clostridium

MCDone (43 decks)

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