MIDTERMS: L1 - STREAKING TECHNIQUE Flashcards

1
Q

The process of growing microorganisms in culture by taking bacteria from the infection site( in vivo environment) and Growing microorganisms in an artificial environment in the laboratory (in vitro)

A

Cultivation

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2
Q

Survival depends on the availability of essential nutrients and appropriate environmental conditions. T OR F

A

True

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3
Q

First and most important steps required for bacterial identification and characterization.

A

Ability to select pure (individual) colonies

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4
Q

If sufficient inocula for testing can be obtained from the primary media, then subculture is NOT necessary. T or F

A

True

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5
Q

Steps in pour plate method

A
  1. Inoculate an empty plate
  2. Add melted nutrient agar
  3. Swirl to mix
  4. Colonies grow in and on solidified medium
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6
Q

Steps in spread plate method

A
  1. Inoculate plate containing solid medium
  2. Spread inoculum over surface evenly
  3. Colonies grow only on surface of medium
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7
Q

For isolation and semiquantitative of bacterial

colonies

A

Dilution streak technique

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8
Q

Plates inoculated for quantitation are usually streaked with a 1:100 or 1:1000 loop. T or F

A

True

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9
Q

Specimens plated quantitatively

A

Urine culture and tissues from burned patients

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10
Q

A technique used to isolate pure strain from a

single species of microorganisms

A

Streaking

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11
Q

1st quadrant: Heavy confluent growth
2nd quadrant: discrete colonies
MOTF

A

1st true, 2nd false (4th quadrant = discrete colonies)

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12
Q

Lawn Streaking Technique is used for antimicrobial susceptibility testing
T or F

A

True

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13
Q

Stab and Streak Method is commonly used for biochemical testing of enteriobacterciae

A

True

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14
Q

Difference between TSI and LIA in terms in stabbing or streaking

A

TSI - stab streak

LIA - stab streak stab

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15
Q

Urase and Citrate medium - stabbing the center

Sulfide Indole Motility medium - zigzag needle

MOTF

A

Both False (Urease and Citrate - zigzag, SIM - stab the center)

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16
Q
Pathogenic bacteria (Mesophilic) - prefer 30 to 45 degree celcius
Skin Pathogens - 30 degree celcius

MOTF

A

Both T
(Others:
Thermophlies - >40 degree celcius
Psychrophiles - 4 to 20 degree celcius)

17
Q

Most of the incubators in the laboratory are set at what temperature

A

35 degrees celsius ± 2 degrees celsius - to meet the preferred temperature of most internal human pathogens

18
Q

Plates SHOULD NOT be STACKED in piles of MORE THAN SIX

T or F

19
Q

The media should be poured in the petri plates at a

specific temperature usually at ______

A

45 degree celcius

20
Q

To prevent contamination from moisture during incubation: petri dishes should be placed at

A

Inverted position

21
Q

Anaerobic cultures are incubated for a longer period, ranges from 3 to 6 days
T or F

22
Q

Gram positive bacteria generally produce bigger colonies than gram
negative bacteria
T or F

A

False - GP produce smaller colonies

23
Q

Relative terms of colony size:

A

Punctiform or pinpoint, small, medium, large

24
Q

Colony pigmentation of Serratia marcescens and Pseudomonas aeruginosa

A

SM - RED

PA - GREEN

25
Pseudomonas aeruginosa illustrating the _________ in blood agar plate (BAP)
Metallic sheen and green pigmentation of colonies
26
Brick red pigment of Serratia marcescens which is evident on what agar
MacConkey | Additional info: dditional incubation at room temperature enhances the brick-red pigmentation.
27
Enumerate three colony shape
Form, Elevation, and Margin
28
The edge of the colonies should be observed in the form or margin T or F
True (Form - smooth, filamentous, rough, or irregular)
29
Colonies of _______on visual examination are described as “medusa heads” because of the filamentous appearnce
Bacillus anthracis
30
The elevation of colonies should be determined by | __________
Tilting the culture plate and looking at the side of the colony
31
Umbonate is described as a depressed center, concave on the inside Umbilicate is described as having a bulging center and convex on the outside MOTF
Both False - Umbilicate is described as a depressed center, concave on the inside - Umbonate is described as having a bulging center and convex on the outside
32
Streptococcus pneumoniae produces umbilicate colonies | T or F
True
33
Colony margin (enumerate the types)
Entire or smooth, and irregular
34
To see the differences in the density of colonies, it is useful to look through the colonies while using _______
Transillumination - passing of bright light through the bottom of the plate
35
Translucent colonies allow some light to pass through the colonies and opaque colonies do not T or F
True
36
Hemolysis is helpful in the presumptive identification of Streptococci and Enterococci T or F
True
37
Alpha hemolysis- partial lysis of RBCs in a BAP around and under the colony that results in a green discoloration of the medium Beta hemolysis- complete hemolysis of RBCs in a BAP around or under the colony Gamma hemolysis- no hemolysis MOTF
All True
38
Odor: S. aureus P. mirabilis Nocardia spp.
S. aureus - old sock P. mirabilis - putrid Nocardia spp. Freshly plowed field
39
Odor: P. aeruginosa- Haemophilus spp. -
P. aeruginosa- fruity or grapelike | Haemophilus spp. - mousy