MICROBIOLOGY- Classification and identification of bacteria of medical importance Flashcards

1
Q

Name the three types of microorganisms

A
  1. Eukaryotes
  2. Prokaryotes
  3. Viruses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name the most abundant micro organism on earth

A

Bacteria

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

Name the two types of bacterial cell structure

A

Gram positive

Gram Negative

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

Describe the structure of gram negative bacteria

A

They have a thin cell wall surrounded by a phospholipid membrane

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

How do we study bacteria

A

We need to isolate them in a pure culture

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

Can all bacteria be cultured

A

No as we can’t re create the environment for some bacteria to grow

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

State different initial characteristics we look at when studying bacteria

A
  1. Colony morphology

2. Cell morphology

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

What can we look at when studying bacterial colony morphology

A
  1. Shape
  2. Haemolysis
  3. Pigment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Name the 3 categories we can put bacteria in when looking at haemolysis

A
  1. Alpha haemolysis
  2. Beta haemolysis
  3. Gamma haemolysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is alpha haemolysis?

A

A partial or “green” hemolysis associated with reduction of red cell hemoglobin.

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

What is beta haemolysis?

A

complete lysis of red cells in the media around and under the colonies: the area appears lightened (yellow) and transparent

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

What can we look at when studying bacterial cell morphology

A
  1. Shape
  2. Spores
  3. Gram stains
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do we carry out gram staining

A
  1. Fixation : isolate a colony and place it on a glass slide
  2. Flood the surface of the glass slide with Crystal violet
  3. Rinse
  4. Flood the surface of the glass slide with Iodine
  5. Gram negative will Decolourise and the gram positive will turn purple
  6. Counter stain to identify gram negative
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Following a Gram staining what colour will gram positive bacteria be?

A

Purple/ violet

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

Following a Gram staining what colour will gram negative bacteria be?

A

Pink

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

List differential characteristics we can look at when studying bacteria

A
  1. Metabolic activities
  2. Antigens
  3. Cellular composition
  4. DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How do we describe a bacterias metabolic activities?

A
  1. Fermentations
  2. Gas or gas production
  3. Enzymes
  4. utilisation of carbohydrates and proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Name some Molecular techniques we can use to look at bacterial DNA

A
  1. PCR
  2. Nucleic acid sequences
  3. Homology
  4. Probes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Name different tests we use to classify bacteria

A
  1. The Ziehl-Neelsen stain
  2. Catalase test
  3. Coagulase test
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is another name for the Ziehl-Neelsen stain ?

A

The acid fast stain

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

What do bacterial cell walls contain high concentration of?

A

Lipid

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

Name the 3 steps of the Ziehl-Neelsen stain

A
  1. Staining using carbon fuchsin (pink)
  2. Decolorisation
  3. Staining using methyl blue (blue)
  4. Oxidase test
23
Q

How do we carry out the catalase test?

A
  1. Take a sample of a colony and place it onto an agar plate
  2. Make a smear of the colony into a glass slide
  3. Add hydrogen peroxide
  4. If the catalase enzyme is produced by the enzyme it will hydrolyse the hydrogen peroxide into H20
  5. This will show up as bubbles on the glass slide (catalase positive)
24
Q

What does the catalase test show?

A

If the bacteria in question produces the catalase enzyme

25
Q

What does the coagulase test show?

A

If the bacteria in question produces the coagulase enzyme

26
Q

Why do we carry out the coagulase test?

A

To see if the bacteria we are testing is staphylococcus aureus

27
Q

What is the oxidase test used to determine?

A

If the bacteria in question can produce cytochrome c oxidases

28
Q

How do we carry out the oxidase test?

A

We use tetra methyl para phenyl di amine

If it turns blue then the bacteria is oxidase positive

29
Q

Give examples of gram positive bacilli

A
  1. Mycobacterium tuberculosis,
  2. Mycobacterium leprae.
  3. M§ycobacterium avium-intracellulare
  4. Nocardia spp
30
Q

Give examples go spore producing gram positive bacilli

A
  1. Bacillus anthracis
  2. Bacillus cereus
  3. Clostridium spp
  4. Clostridium tetani
  5. Clostridium botulinum
31
Q

What does Bacillus anthracis cause?

A

Anthrax

32
Q

What does Bacillus cereus

A

Food poisoning

33
Q

What does Clostridium tetani cause?

A

Tetanus

34
Q

What does Clostridium botulinum cause?

A

Botulism

35
Q

Give examples of motile and non sporing bacilli

A

Listeria spp eg Listeria monocytogenes

36
Q

Where is Listeria monocytogenes found and what does it cause?

A

In foods such as cheese and pâtés, it causes listeriosis.

37
Q

Give examples of non motile and non sporing bacilli

A
  1. Corynebacteria
  2. Propionibacteria
  3. Lactobacilli
38
Q

What does Corynebacteria cause?

A

diphtheria

39
Q

What does Propionibacteria cause?

A

Acne

40
Q

Give examples of gram positive cocci

A
  1. staphylococci

2. streptococci

41
Q

Give examples of gram negative cocci

A
  1. Veillonella spp
  2. Parvobacteria
  3. acinobacters
  4. Neisseria spp.
  5. Neisseria spp.
42
Q

What do Neisseria spp cause?

A

meningococcal meningitis

43
Q

Give examples of gram negative bacilli

A
  1. Haemophilus spp.
  2. Legionella spp.
  3. Bordetella spp.
44
Q

What do Haemophilus spp cause?

A

associated with respiratory infections

May also cause epiglottitis

45
Q

What can Legionella pneumophila cause

A

Can cause Legionaire’s disease

46
Q

What can Bordetella spp.

A

Bordetella pertussis causes whooping cough.

47
Q

Give examples of gram negative bacilli

A
  1. Escherichia coli
  2. Yersinia pestis
  3. Shigella dysenteriae
  4. Salmonella spp.
  5. Providencia spp.
48
Q

What did Yersinia pestis cause?

A

Plague

49
Q

What is Shigella dysenteriae responsible

A

Responsible for bacterial dysentery

50
Q

What can Salmonella enterica

cause

A

gastroenteritis

51
Q

What can Salmonella typhi cause?

A

Typhoid fever

52
Q

What can Providencia spp cause

A

Members of this genus cause urinary tract infections

53
Q

What can Campylobacter spp cause

A

Bacterial diarrhoea

54
Q

What can Brucella spp cause

A

brucellosis (“undulant fever”).