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1
Q

What rapid tests are used in the lab?

A

Immuno-based assays

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2
Q

What are rapid strep tests for?

A

Diagnosis of Strep. Pyogenes

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3
Q

what type of antigens do strep tests look for?

A

group A strepococcal antigens

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4
Q

what binds to an antigen when it has dye attached?

A

antibodies

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5
Q

what is being detected in an immuno-based assay test?

A

a protein that is specific to a pathogen or a condition

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6
Q

what is the most common point-of-care testing format?

A

rapid immunoassays that employ test strips

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7
Q

what are point-of-care tests?

A

tests that are conducted by healthcare workers or patient without the need for any other lab equiptment

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8
Q

if the specimen being tested contains Group A strep bacteria, the strep antigens extracted from the throat swab will what?

A

bind to these antibodies

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9
Q

what is the “test” region for the strep test?

A

retention of the dye-colored antigen/antibody complexes

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10
Q

what indicates that the sample is positive for Group A strep?

A

colored line at the test line region

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11
Q

what does the test region also contain in the strep A test?

A

fixed antibodies that will bind directly to dye-labeled antibodies

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12
Q

what does a strep test positive result look like?

A

2 lines running through the test region and control region

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13
Q

what does a strep negative result look like?

A

one line in the control region

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14
Q

what does an invalid result look like in a strep test?

A

one line in the test region

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15
Q

are rapid strep tests foolproof?

A

no

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16
Q

what is involved in a rapid staph test?

A

latex bead agglutination tests

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17
Q

how is a rapid staph test done?

A

coated latex beads are mixed with the test organism and allows to interact

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18
Q

what does a positive rapid staph test look like?

A

beads will appear and clump up

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19
Q

what does a negative rapid staph test look like?

A

the beads will reman in a a homogenous suspension

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20
Q

what type of species is the rapid staph test specific to?

A

staph. aureus

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21
Q

what do all pathogenic strains of S. aureus produce?

A

a bound coagulase and contain Protein A on their cell surface

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22
Q

what are the latex particles in a rapid staph test coated with?

A

human fibrinogen and IgG

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23
Q

what are the steps of a rapid strep test?

A
  1. add 4 drops of regeant A to the tube
  2. add 4 drops of reagent B to the tube
  3. place throat swab in the tube
  4. squeeze the swab against the tube
  5. remove group A test strip and put into tube
  6. read results
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24
Q

what color will the solution be after adding reagent A in a rapid strep test?

A

light red

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25
Q

what color will the solution be after adding the reagent B in a rapid strep test?

A

will turn a pale yellow

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26
Q

how many times do you agitate the swab in the tube for the rapid strep test?

A

10 times

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27
Q

how long is the throat swab left in the tube of the strep test?

A

1 minute

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28
Q

what is the correct end of the group A test strip?

A

wavy lines

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29
Q

how long does it take to read the results of a rapid strep test? when do you not read the results?

A
  • 5 min

- 10 min

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30
Q

what are the steps of a rapid staph test?

A
  1. make sure the card is flat
  2. dispense 1 drop of test latex onto both of the circles on the reaction card
  3. dispense 1 drop of negative control solution onto one circle on the reaction card
  4. use a sterile loop and smear a colony onto the other test-latex-containing circle
  5. pick up a hand rock card
  6. dispose of the card
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31
Q

how long should you hand rock the rapid staph test card?

A

20 seconds

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32
Q

should the control latex agglutinate?

A

no

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33
Q

why is the test region placed before the control region on the rapid strep test?

A

so the antibodies can reach the test region but not reach the control region

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34
Q

what is critical throughout the unknown project?

A

to use appropriate aseptic technique to prevent introducing environmental organisms into your cultures

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35
Q

what is the initial step of the unknown isolation?

A

gram staining

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36
Q

what is an essential step for most microbial identification strategies?

A

obtaining pure cultures

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37
Q

what are the steps of part 1 of the unknown project?

A
  1. observation of mixed culture by gram staining
  2. obtaining isolated colonies
  3. identify isolated colonies that are pure by observing gram stains
  4. inoculate stock slants with bacteria from a isolated and pure colony
  5. confirm the purity of your stock slants
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38
Q

why do we gram stain our unknown project in the beginning?

A

to confirm mixed culture and assess arrangement

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39
Q

what are the 3 types of agars we use in our isolation streaks?

A
  1. nutrient/ TSA
  2. PEA
  3. MacConkey
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40
Q

is the TSA gram positive, negative or both?

A

both

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41
Q

is the PEA gram positive, negative or both?

A

gram positive

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42
Q

do we use the MacConkey agar to identify pure colonies?

A

no

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43
Q

what type of test did we do to properly classify gram positive organisms?

A

catalase test

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44
Q

what is the catalase test used to do?

A

differentiate staphlyococcal species from strep/enterococcal species

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45
Q

what is the catalase test based on?

A

how these organisms detoxify hydrogen peroxide

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46
Q

what exactly is catalase?

A

an enzyme that converts hydrogen peroxide into water and molecular oxygen

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47
Q

what is the catalase test’s first step?

A

collect a sample of gram positive organism

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48
Q

what is the catalase test’s 2nd step?

A

place 2 drops of 3% hydrogen peroxide into end of swab

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49
Q

what is the last step in the catalase test?

A

immediately look for bubbling reaction and record results

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50
Q

what is the presence of bubbles mean in the catalase test?

A

indicates the presence of catalase and positive test result

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51
Q

is the novobiovin sensitivity and growth characteristics on MH agar s catalase positive or catalase negative test?

A

catalase positive

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52
Q

what plate is divided in two sections in the Novobiocin sensitivity test?

A

Muller-hinton plate

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53
Q

what does college gram positive culture create?

A

a bacterial lawn on top portion

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54
Q

what do you put on the top half of the MH plate?

A

Novobiocin

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55
Q

is the DNAse agar plate preformed for a catalase positive or negative test?

A

catalase positive

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56
Q

how is the DNAse agar plate test done?

A
  1. collect gram positive and inoculate the DNAse agar plate

2. tape the plate closed and incubate at 37C

57
Q

what are the steps in the Mannitol salt agar plate?

A
  1. label
  2. inoculate the MSA with a straight line streak
  3. tape plate closed
58
Q

what are the steps in the PYR broth?

A
  1. label
  2. inoculate the broth
  3. incubate
59
Q

what are catalase positive tests?

A
  • Novobiocin sensivity
  • DNAse agar streak
  • MSA agar
  • PYR broth
60
Q

what does the PYR broth test for?

A

aminopeptidase PYR

61
Q

what does the MSA agar plate test for?

A

Mannitol Fermentation

62
Q

what does the DNAse agar test for/

A

DNAse activity

63
Q

what does the MH agar plate test for?

A

Novobiocin sensitivity or resistance

64
Q

what are the types of catalase negative tests?

A
  • STX sensitivity test
  • BEA slant streak
  • PYR broth
65
Q

what type of bactrim STX grow on?

A

blood agar

66
Q

what type of media is blood agar?

A

differential and enriched

67
Q

what is beta hemolysis?

A

complete lysis of red blood cells

68
Q

what is alpha hemolysis?

A

partial hemolysis of red blood cells

69
Q

what are the three types of hemolysis in bacterium STX test?

A
  1. beta
  2. alpha
  3. none
70
Q

what type of medium is BEA?

A

selective and differential

71
Q

what does the BEA test focus on?

A

positive or negative for esculin hydrolysis

72
Q

what is considered a positive test in the BEA slant?

A

50% of slant should be grey/black

73
Q

is the PYR broth a test in both gram positive cocci tests?

A

yes

74
Q

what does a positive result look like in the PYR broth?

A

a red color will be produced

75
Q

what does a negative result look like in the PYR test?

A

light orange color

76
Q

what does a positive novobiocin sensitivity test?

A

zone of inhibition > 16mm

77
Q

what is a negative novobiocin sensitivity test?

A

less than 16mm it is resistant

78
Q

what is a positive DNAse agar test results look like?

A

a clear zone is observed

79
Q

what is a positive MSA result look like?

A

zone of inhibitation >20mm

80
Q

what is a negative blood agar plate result look like?

A

less than 20mm is resistant

81
Q

what type of media is MSA?

A

selective and dfferential

82
Q

what does the MSA contain?

A

7.5% NaCl

83
Q

what is a positive result of MSA test?

A

phenol red turns yellow

84
Q

colonies that are >3mm are considered?

A

large

85
Q

colonies that are <1mm are considered?

A

small

86
Q

what is the universal virulence factor in all gram-negative bacteria?

A

LPS in outer membrane

87
Q

what does the universal virulence factor cause?

A

morbidity and mortality

88
Q

what is the collection of biochemical tests called that we did on gram negatives?

A

microgen GNA-ID system

89
Q

what species of gram negatives did the collection of biochemicals test identify?

A

enterobacteriaceae species

90
Q

how many wells were there in the microgen GNA-ID system?

A

12 wells

91
Q

what did each well contain?

A
  • dehydration substrates

- indicators in saline

92
Q

what is the purpose of well 1?

A

to determine if the organism is able to carry out lysine decarboxylation

93
Q

why was well 1 overlaid with mineral oil?

A

to generate an anaerobic environment

94
Q

what is the purpose of well 2?

A

to determine if the organism is able to carry out ornthine decarboxylation

95
Q

why was well 2 overlaid with mineral oil?

A

well 2 is anaerobic

96
Q

what is the purpose of well 3?

A

to see which organisms produce the enzyme thiosulfate reductase

97
Q

Does Well 3 need an anaerobic or aerobic environment? How is this solved?

A
  • anaerobic

- overlaying mineral oil

98
Q

what do wells 4,5,6 test for?

A

the organisms ability to metabolize various carbohydrates

99
Q

what does well 7 contain?

A
  • ONPG

- nitrate

100
Q

how many tests does well 7 provide?

A

2 tests

101
Q

what does well 7 test for/

A

first is the apperance of Beta-galactosidase activity

102
Q

how is the nitrate reduction test preformed in well 7?

A
  • second test after ONPG
  • nitrate reagent A added first
  • nitrate reagent B added
103
Q

what happens if no color appears in the nitrate reduction test in well 7?

A

add a pinch of zinc and it is negative

104
Q

what is the purpose of well 9?

A

to detect urease activity

105
Q

what is the purpose of well 10?

A

to detect bacteria that ferment glucose but only produce one acid end produce

106
Q

what test is done in well 10?

A

VP test

108
Q

how long does the VP test in well 10 take?

A

15-30 min

109
Q

what does well 8 test for?

A
  • presence of tryptophanase

- indole production

110
Q

what is added to well 8?

A

kovac’s reagent

111
Q

what does well 11 test for?

A

citrate utilization

112
Q

what does well 12 test for?

A

trypotphan deaminase activity

113
Q

define bioinformatics

A

the use of computational tools to address biological questions

114
Q

what is our primary collections of bioinformatics tools?

A

NCBI

115
Q

what is the NCBI a division of?

A

the national library of medicine

116
Q

what does the NCBI serve as?

A

a gateway for researchers to access informatio

117
Q

what does BLAST stand for?

A

basic local alignment search tool

118
Q

define BLASTn

A

uses a neucleotide sequence and searches a nucleotide database

119
Q

define BLASTp

A

A nucleotide or amino-acid sequence information

120
Q

what sequence should the Query sequence be entered in?

A

FASTA format

121
Q

define electrophoresis

A
  • a technique that separates molecules

- based on size

122
Q

define PCR

A

a technique that can exponentially amplify a fragment of DNA in a test tube

123
Q

what type of PCR reaction will we preform on our unknown?

A

in silico

124
Q

how is the amplicon determined in the PCR reaction?

A

by primers

125
Q

define sanger sequencing

A

technique to sequence DNA

126
Q

what is important when running a PCR test?

A

dispense the master mix back into PCR tube

127
Q

what electrodes should be properly connected?

A

black and red

128
Q

When the dark blue running dye has travelled ___ of the length of the gel, turn the power supply off and disconnect the _____

A
  • 3/4

- electrodes

129
Q

what is fermentation?

A

a collection of bacterial metabolic processes that engage when respiration (aerobic or anaerobic) is not possible

130
Q

what does fermentation result in?

A

the production of acidic waste products

131
Q

What does the production of acidic products such as lactic acid, propionic acid, and acetic acid through fermentation result in?

A

conditions that alter the characteristics of the raw food product

132
Q

Fermentation not only increases the concentration of _____ or _______ (SCFAs), but also the diversity of ______ products

A
  • lactate
  • short-chain fatty acids
  • metabolic
133
Q

what are the most commonly comsumed fermented products?

A

diary

134
Q

what does adding salt do in vegetable ferments?

A

support the production of a brine

135
Q

what illness continue to be a significant source of bacterial disease in he US?

A

foodborne

136
Q

what are S&S agar plates selective for?

A

enteric gram negative organisms

137
Q

Escherichia species are ____ ____ and appear as ____ colonies on S&S Agar

A
  • lactose positive

- red

138
Q

Both Salmonella and Shigella species are _____ ___ and appear as __________ colonies on S&S Agar

A
  • lactose negative

- clear/tan

139
Q

Foodborne Pathogens Lab steps

  1. Take a ________ __ plate and divide the plate in ___.
  2. Using a ____, roll over the _____ sample to collect organisms. Then swab the ____ portion of the S&S plate.
  3. Using a sterilize ____ to collect some bacteria from the ____ of the plate and streak them out across the _____ half of the plate to obtain _______ _____
  4. Using ______, securely close the plate prior to incubating at 37oC for 48 hours
A
  • S&S agar, half
  • swab, meat, loop-loop, top, lower, isolated colonies
  • parafilm

Microbiology lab practical #2 (1 decks)

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