(Laboratory) Identification of Staphylococcus Flashcards
1
Q
List down the step-by-step procedure in the Collection of the Bacterial Sample for Staphylococcus.
A
- Use sterile cotton swab to collect bacterial sample in the skin/nasal cavity
- Inoculate the sample in MSA
- Incubate at 37C for 18-24 hours
- Observe for growth and color development
2
Q
What do we use to collect a bacterial sample for the patient?
A
Sterile Cotton Swab
3
Q
Site where we collect the bacterial sample from the patient.
A
Skin or Nasal Cavity
4
Q
What medium is used to inoculate the sample from the collected bacterial sample?
A
MSA or Mannitol Salt Agar
5
Q
Incubation period from the collected bacterial sample in MSA.
A
37C for 18-24 hours
6
Q
Positive result in the Collection of Bacterial Sample
A
Yellow colonies
7
Q
List down the step-by-step procedure in the Colonial Morphology.
A
- Get an inoculum and streak the BAP using multiple interrupted streak method
- Incubate at 37C for 18-24 hours
- Examine the colonies and describe
8
Q
Medium used in the Colonial Morphology.
A
BAP (Blood Agar Plate)
NA (Nutrient Agar)
9
Q
Incubation period for Colonial Morphology.
A
37C for 18-24 hours
10
Q
List down the step-by-step procedure in the Cell Morphology on Gram stain.
A
- Using a sterile loop, place a loopful of saline into a labelled slide
- Emulsify a colony into the saline
- Air dry and heat fix
- Stain with gram stain
- View under microscope (OIO)
11
Q
What is seen on Cell Morphology on Gram Stain of Staphylococcus?
A
Gram positive cocci in clusters
12
Q
List down the step-by-step procedure in the Oxidase Test.
A
- Using a sterile loop/applicator stick, rub a colony into the oxidase strip
- Observe for color change
13
Q
What is the positive result in the Oxidase Test?
A
Purplish to black
14
Q
What is the negative result in the Oxidase Test?
A
No color change
15
Q
List down the step-by-step procedure in the Catalase Test.
A
- Place 1 drop of 3% hydrogen peroxide reagent in a glass slide
- Emulsify a colony using applicator stick
- Observe
16
Q
How many drops of the 3% hydrogen peroxide reagent is added in the Catalase Test procedure?
A
1 drop
17
Q
Reagent used in the Catalase Test.
A
3% hydrogen peroxide reagent
18
Q
What is the positive result in the Catalase Test?
A
Bubble Formation
19
Q
What is the negative result in the Catalase Test?
A
No gas bubbles
20
Q
List down the step-by-step procedure in the DNAse Test.
A
- Using bacteria from a plate, inoculate the DNAse medium in a straight line
- Incubate the DNAse medium for 18-24 hours
- After incubation, add a small amount of 1N HCl to the plate, flooding the colonies.
- Discard the excess acid and observe the media surrounding the colonies.
21
Q
Incubation period in the DNAse Test.
A
18-24 hours
22
Q
What is added to the plate of the DNAse medium after the incubation?
A
1N HCl (1 Normal Hydrochloric acid)
23
Q
Positive result in the DNAse Test.
A
Clearing surrounding the colonies
24
Q
Screening Coagulase Test
A
Slide Coagulase
25
Confirmatory Coagulase Test
Tube Coagulase Test
26
What is added on the "T" portion on the slide of the Slide Coagulase Test?
Plasma
27
What is added on the "C" portion on the slide of the Slide Coagulase Test?
Saline
28
The "T" on the slide for the Slide Coagulase Test means _____
Test
29
The "C" on the slide for the Slide Coagulase Test means _____
Control
30
Positive result in the Slide Coagulase Test
Clumping
31
Negative result in the Slide Coagulase Test
No Clumping
32
A negative control in the Slide Coagulase Test should show (clumping or no clumping).
No clumping
33
List down the step-by-step procedure in the Tube Coagulase Test.
1. Add 0.5 mL of plasma into a tube
2. Inoculate a loopful of bacteria
3. Incubate for 2 hours and observe for clot formation
4. If no clot is observed, incubate for another 2 hours and observe for clot formation
5. If no clot is observed after a total of 4 hours incubation, incubate further up to 18-24 hours
34
Specimen used in the Tube Coagulase Test (In Laboratory Setting)
0.5 mL of Plasma
35
Positive result in the Tube Coagulase Test
Coagulum
36
Negative result in the Tube Coagulase Test
No Coagulum
37
An enzyme that catalyzes the release of oxygen from hydrogen peroxide (H2O2)
Catalase
38
A test that demonstrate the presence of catalase
Catalase Test
39
Reagent used for the routine culture of Catalase Test
3% H2O2
40
Reagent used for the detection of catalase in anaerobe
15% H2O2
41
An enzyme-like protein and causes plasma to clot by converting fibrinogen to fibrine
Coagulase
42
Best single pathogenicity test for Staphylococcus aureus
Coagulase Test
43
Specimen used in the Slide Method of Coagulase Test? (According to the Recorded Lecture)
Plasma
44
A method under the Coagulase Test that detects bound coagulase
Slide Method
45
Positive result in the Slide Method of Coagulase Test
Agglutination
45
Positive result in the Slide Method of Coagulase Test
Agglutination
45
Positive result in the Slide Method of Coagulase Test
Agglutination
46
Specimen used in the Tube Method of Coagulase Test? (According to the Recorded Lecture)
0.5 mL rabbit’s plasma
47
A method under the Coagulase Test that detects unbound coagulase (staphylocoagulase)
Tube Method
48
Positive result in the Tube Method of the Coagulase Test
Coagulum/Clot
49
Medium used in the Oxidation-Fermentation (O/F) Reactions Test
O/F Glucose Medium or the Hugh and Leifson’s Medium
50
How many tubes are needed in the Oxidation-Fermentation (O/F) Reactions Test?
2 tubes
51
Describe the 2 tubes in the Oxidation-Fermentation (O/F) Reactions Test.
1st Tube: Overlaid with mineral oil or melted paraffin (Anaerobic Environment)
2nd Tube: Left open in the air (Aerobic Environment)
52
Oxidative utilization of the carbohydrate will result in acid production or color yellow in _____
Open tube only
53
Fermentative utilization of the carbohydrate will result in acid production or yellow in _____
Both open and closed tubes
54
pH indicator in the Oxidation-Fermentation (O/F) Reactions Test
Bromthymol blue
55
The pH indicator bromthymol blue changes into color _____ when it detects acid
Yellow
56
In the Oxidation-Fermentation (O/F) Reactions Test, if the closed tube is positive, what does it indicates?
Yellow Color
Fermentative
57
In the Oxidation-Fermentation (O/F) Reactions Test, if the open tube is positive, what does it indicates?
Yellow Color
Oxidative
58
In the Oxidation-Fermentation (O/F) Reactions Test, if both the open and closed tube is positive, what does it indicates?
Staphylococci specie
59
In the Oxidation-Fermentation (O/F) Reactions Test, if the open tube is positive and the closed tube is negative, what does it indicates?
Micrococcaceae specie
60
Active chemical component in the Modified Oxidase Test
Tetramethyl-para-phenylenediamine dihydrochloride
61
A reagent impregnated disc recommended for use in qualitative procedures to aid in the differentiation of Staphylococcus and Micrococcus by the detection of the oxidase enzyme.
Microdase disc
62
Positive result in the Modified Oxidase Test
Blue to purple to black complex
Micrococci specie
63
Negative result in the Modified Oxidase Test
No color change
Staphylococcus
64
Medium used in the Mannitol Fermentation Test
MSA (Mannitol Salt Agar)
65
Positive result in the Mannitol Fermentation Test
Yellow color
Staphylococcus aureus
66
Negative result in the Mannitol Fermentation Test
Pink color
Coagulase-negative Staphylococci specie
67
pH indicator in the Mannitol Fermentation
Phenol red
68
Phenol red turns _____ when it detects acid
Yellow
69
Medium used in the DNAse Test
DNAse medium
70
Positive result in DNAse Test
Staphylococcus aureus
71
Negative result in DNAse Test
Staphylococcus epidermidis
72
A test used to determine the ability of an organism to hydrolyze DNA and utilize it as a source of carbon and energy for growth.
DNAse Test
73
Medium used in the Gelatin Liquefaction/Hydrolysis Test
12% Gelatin Medium
74
Incubation period in Gelatin Liquefaction/Hydrolysis Test
35ºC for 16-18 hours
75
Positive result in Gelatin Liquefaction/Hydrolysis Test
Staphylococcus aureus
76
Negative result in Gelatin Liquefaction/Hydrolysis Test
Staphylococcus epidermidis
77
A protein derived from the connective tissues of vertebrates that is collagen
Gelatin
78
These are proteases secreted extracellularly by some bacteria which hydrolyze or digest gelatin.
Gelatinases
79
Staphylococcus aureus is coagulase (positive or negative)
Coagulase positive
80
Staphylococcus epidermidis is coagulase (positive or negative)
Coagulase negative
81
Staphylococcus saprophyticus is coagulase (positive or negative)
Coagulase negative
82
Staphylococcus aureus is novobiocin (susceptible or resistant)
Novobiocin susceptible
83
Staphylococcus epidermidis is novobiocin (susceptible or resistant)
Novobiocin susceptible
84
Staphylococcus saprophyticus is novobiocin (susceptible or resistant)
Novobiocin resistant
85
Sugar fermentation is of no diagnostic value except for _____, which is usually fermented anaerobically by Staphylococcus aureus but not by other species
Mannitol
