Brainscape's Knowledge GenomeTM

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


See full index

MCD Microbiology > Community acquired bacterial infections > Flashcards

Community acquired bacterial infections Flashcards

1
Q

Name some examples of cocci bacteria

A

Staphylococci, streptococci, sarcina and tetrad

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

Name some examples of bacilli bacteria?

A

Coccobacillus, bacillus, diplobacilli, palisades, streptobacili

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

Name the common virulence factors

A 
Secretion systems
Flagella
Pili
Capsule
Endospores - resistant to heat, cold, desiccation and chemical resistant 
Exotoxins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the different types of exotoxins?

A

Neurotoxins- Act on nerves or motor endplates to cause paralysis e.g. tetanus and botulinum toxin
Enterotoxins- GI tract to cause diarrhoea- inhibit NaCl resorption, activate NaCl secretion or kill intestinal epithelial cells- commune end result is osmotic pull of fluid into the intestine which causes diarrhoea
Pyrogenic exotoxins- stimulate release of cytokines and can cause rash, fever and toxic shock syndrome
Tissue invasive exotoxin
Miscellaneous exotoxin

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

How does infectious diarrhoea occur?

A

Bacteria colonise and bind to the GI tract, continuously releasing their enterotoxin locally. Diarrhoea will continue until bacteria are destroyed by the immune system or antibiotics

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

Give some examples of infectious diarrhoea diseases?

A

Vibro cholera
Escherichia coli
Campylobacter jejuni
Shigella dysenteriae

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

Describe the process of food poisoning?

A

Bacteria grow in food and release enterotoxin into the food. The enterotoxin is ingested resulting in diarrhoea and vomiting for less than 24 hours

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

Give some examples of food poisoning bacteria?

A

Staphylococcus aureus and bacillus cereus

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

What are endotoxins?

A

Lipid A part of LPS, component of gram negative bacterium

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

What is septic shock?

A

Sepsis that results in dangerous drops in blood pressure and organ dysfunction

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

What is septic shock also known as?

A

Endotoxin shock because endotoxin often triggers the immune response that results in sepsis and shock (but adverse effects in gram-positive bacteria or even fungi can trigger adverse immune response)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
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 period of time or a particular place or both

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

How can an outbreak be identified?

A

Surveillance systems provide an opportunity to identify outbreaks- report to a central system to identify the spread
Good and timely reporting systems are instrumental

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

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

A

Entero-aggregative shiga-toxin producing e coli

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

What did the E.coli outbreak lead to?

A

Gastroenteritis and haemolytic-uremic syndrome

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

What was the e.coli outbreak spread by?

A

Consumption of sprouts

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

What is haemolytic-uremic syndrome?

A

Acute renal failure, haemolytic anaemia and thrombocytopenia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Who is HUS normally found in?

A

Children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the normal reservoir for HUS?

A

Cattle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does infection occur of HUS in humans?

A

Inadvertent ingestion of decal matter and secondary through contact with infected humans- very rare in adults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What do you need to define an outbreak?

A

Cause, characteristics, scale, time-frame, source, illness, involvement of different strains, symptoms to look for etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What can you do once you know the genome of the bacteria to detect the outbreak strain?

A

Do PCR in stool samples etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the structure of shiga/vero toxin?

A

Subunit a (StxA) is non covalently associated with a pentamer of protein B (StxV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the role of StxA?

A

Enzymatically active domain- it is an enzyme that cleaves the 28S ribosomal RNA in eukaryotic cells leads to inhibition of protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the StxB pentamer responsible for?

A

Binding to host cell receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are bacterial ribosomes a substrate for and what is the effect?

A

StxA and it will result in decreased proliferation of susceptible bacteria which might affect the commensal microflora in the gut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are shiga toxins encoded on?

A

A bacteriophage (highly mobile genetic element which contributes to horizontal gene transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What caused the outbreak in Germany?

A

Horizontal gene transfer of shiga toxin from EHEC strain to EAEC strain of coli, which also has a virulence factor- aggregative adherence fimbriae (AAF) which is required for adhesion to to enterocytes in gut. It also stimulates a strong IL-8 response which allows biofilm formation and additional virulence factors.

29
Q

What are the different types of communicable disease in Europe?

A

Respiratory tract infections
Sexually transmitted infections, including HIV and blood-borne viruses
Food and waterborne diseases and zoonoses
Emerging and vector borne diseases
Vaccine preventable diseases
Antimicrobial resistance and healthcare associated infections

30
Q

Give examples of respiratory tract infections?

A

Influenza (human, avian and animal)
Legionnaire’s disease
Tuberculosis

31
Q

What type of bacteria is legionella pneumophila?

A

Gram-negative bacterium

32
Q

Where is legionella pneumophila?

A

Lives in amoeba in ponds, lakes, air conditioning units, whirlpools etc

33
Q

What is the infection route of legionella pneumophila?

A

Inhalation of contaminated aerosols

34
Q

What does L. pneumophila affect in humans?

A

It will infect and grow in alveolar macrophages

35
Q

What is the important virulence factor in l.pneumophila?

A

Type IV secretion system which allows secretion of effector proteins to cytoplasm of host cells which allows legionella to replicate in a legionella containing vacuole within the host cell

36
Q

What sort of bacteria are mycobacterium tuberculosis?

A

It groups with gram positive but are structurally very different as they have a cell wall with an extra lipid layer. This makes treatment more difficult

37
Q

What is the latent state of TB?

A

Evidence of infection by immunological tests but no clinical signs and symptoms of active disease

38
Q

What makes treatment of TB difficult?

A

There is often a mixture of active and latent so it is difficult to treat bacteria in different states

39
Q

What is the treatment success rate of TB (for 1st and then second infection)?

A

It is 78% and decreases to 53% for 2nd infection as well as further decreasing to 32% in multi drug resistant TB

40
Q

Give examples of sexually transmitted infections?

A 
Chlamydia trachomatis infection
Gonorrhoea
Hepatitis B
Hepatitis C
HIV/AIDS
Syphilis
41
Q

What type of bacteria is chlamydia trachomatis and what does this mean?

A

It is an obligate intracellular gram negative pathogen so can’t culture it outside host cell

42
Q

What is the most frequent STI in europe?

A

Chlamydia 350,000 cases/year

43
Q

How is the infection rate of chlamydia changing?

A

Increasing

44
Q

What percentage of the worlds blindness is chlamydia responsible for?

A

More than 3%

45
Q

What type of bacteria is neisseria gonorrhoeae?

A

Gram negative diplococcus

46
Q

How does neisseria gonorrhoeae establish infection?

A

It establishes infection in urogenital tract by interacting with non-ciliated epithelial cells

47
Q

What is the important virulence factor for gonorrhoea?

A

Pili

48
Q

Give some examples of food and waterborne diseases and zoonoses?

A 
Campylobacter sp
Salmonella sp
Bacillus anthracis
Vibro cholera
Listeria monocytogenes
49
Q

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

A

Campylobacteriosis (sporadic cases not outbreaks)

50
Q

What is the highest risk group of campylobacter?

A

Children aged 0-4 years

51
Q

What is infection of campylobacter most likely from?

A

Undercooked poultry

52
Q

What is the virulence factor involved in campylobacter?

A

Adhesion and invasion factors, flagella motility, type IV secretion system, toxin

53
Q

What is salmonella sp. caused by?

A

Undercooked poultry

54
Q

What is the most at risk group of salmonella infection?

A

Small children aged 0-4

55
Q

What is the important virulence factor involved in salmonella?

A

Type III secretion systems (encoded on pathogenicity islands= SPI)- two islands:
SPI1 is required for invasion
SPI2 is for intracellular accumulation

56
Q

How is bacillus anthraces usually transmitted?

A

It is very rare and usually transmission to humans from animals e.g. sheep and cattle
Outbreak in 2009 in UK- IV drug users

57
Q

How does bacillus anthraces cause infection?

A

Infectious particles endospores (high mortality if untreated)

58
Q

What virulence factors are involved in bacillus anthracis?

A

Toxin and capsule (encoded on plasmids)

59
Q

What is cholera?

A

Acute, severe diarrheal disease

60
Q

What can happen without prompt rehydration in cholera?

A

Death can occur within hours of onset of symptoms

61
Q

What is the important virulence factor in cholera?

A 
Type IV fimbria
Cholera toxin (carried on phages)
62
Q

What else does type IV fimbria (TCP phage) serve as apart from a colonisation factor?

A

A receptor for CTX phage encoding cholera toxin- Both bacteriophages can integrate into bacterial genome and form episomal replication intermediates and this is dependent on secretin

63
Q

What does the cholera toxin do?

A

Makes the cell produce cyclic AMP which activates transporters leading to efflux of chloride ions with water movement following

64
Q

What is the risk group for listeria monocytogenes?

A

Immunocompromised, elderly, pregnant and their fetus

65
Q

Why is listeria a big problem?

A

It can cross three tight barriers- intestinal, blood/brain and materno/fetal

66
Q

What has studying listeria allowed understanding of?

A

Actin-based cell mobility

67
Q

What emerging and vector borne diseases are there?

A

Plague (yersinia pestis, gram negative)
Q fever (coxiella burnetti, gram negative)
Smallpox (eradicated)

68
Q

What do vaccine preventable diseases include?

A 
Diphtheria
Invasive haemophillus influenza disease
Invasive meningococcal disease
Invasive pneumococcal disease
Pertussis
Tetanus

MCD Microbiology (6 decks)

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