Day 2: Interpretation Flashcards

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1
Q

What is a positive DN’ase test

A

Zone of clearance around colonies

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2
Q

What is a negative DN’ase test

A

No zone of clearance around the colonies

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3
Q

What organisms produce a positive DN’ase result

A

S. aureus
M. Catarrhalis

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4
Q

What organisms produce a negative DN’ase result

A

S. epidermidis, S. saprophyticus

N. species e.g. N. meningitidis,

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5
Q

What is a positive mannitol salt agar test

A

Yellow colonies on mannitol agar indicate mannitol fermenter and salt tolerant

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6
Q

What is a negative mannitol salt agar test

A

Red colonies on mannitol salt agar indicate non mannitol fermenter but salt tolerant

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7
Q

What species are positive on mannitol salt - yellow/pink and growth?

A

S. aureus

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8
Q

What species are negative on mannitol salt - red/pink but growth

A

S. epidermidis or S. saprophyticus

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9
Q

What does it mean if an organism doesn’t grow on mannitol agar

A

It is not salt tolerant i.e. its a staphylococcus

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10
Q

What does pink colonies on SAIDE agar indicate

A

Staphylococcus aureus

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11
Q

What is a negative Staphaurex plus result

A

No agglutination

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12
Q

What is a positive Staphaurex plus result

A

Agglutination

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13
Q

What species will give a positive Staphaurex plus result

A

Only S. aureus

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14
Q

What species of staphylococcus give a negative staphaurex plus result?

A

Coag negative staph e.g. S. epidermidis or S. saprophyticus

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15
Q

What is a positive result for optochin susceptibility?

A

Susceptibility -> zone of no growth around optochin disk

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16
Q

What is a negative result for optochin susceptibilty?

A

Resistance -> growth around optochin disk

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17
Q

What species will give a positive optochin result?

A

S. pneumonia (susceptible)

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18
Q

What species will give a negative optochin result?

A

S. viridans (resistant)

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19
Q

What is a positive Lancefield test?

A

Agglutination

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20
Q

What is a negative Lancefield test?

A

No agglutination

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21
Q

What does a Lancefield group A indicate?

A

Streptococcus pyogenes

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22
Q

What does a Lancefield group B indicate?

A

Streptococcus agalactiae

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23
Q

What does Lancefield group C indicate?

A

Streptococcus equi (most probable)

Streptococcus epidemicus

Streptococcus equisimilis

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24
Q

What does Lancefield group D indicate?

A

Streptococcus bovis

Or the more probable Enterococcus -> E. faecalis

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25
Q

What does Lancefield group F indicate?

A

Streptococcus anginosus

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26
Q

What does Lancefield group G indicate?

A

Streptococcus canis

Streptococcus dysgalactiae

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27
Q

What is a positive bacitracin test?

A

Susceptible to bacitracin

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28
Q

What is a negative bacitracin test?

A

Resistant to bacitracin

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29
Q

What species give a positive bacitracin test?

A

Streptococcus pyogenes (susceptible)

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30
Q

What species give a negative bacitracin test?

A

Enterococcus species

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31
Q

What is a positive result for MacConkey agar?

A

Pink colonies

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32
Q

What is a negative result for MacConkey agar?

A

Yellow colonies

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33
Q

What species will give a positive result on MacConkey?

A

Enterococci

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34
Q

What species will give a negative result on MacConkey?

A

Streptococci

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35
Q

What is a positive bile aesculin test?

A

Blackening of the medium

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36
Q

What is a negative bile aesculin result

A

No blackening of the medium

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37
Q

What species will give a positive result on bile aesculin agar?

A

Enterococci

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38
Q

What species will give a negative result on bile aesculin agar?

A

Streptococci

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39
Q

What TAXO sugars does N. Meningitidis utilise?

A

Glucose

Maltose

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40
Q

What TAXO sugars does N. Gonorrhoeae utilise?

A

Glucose

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41
Q

What TAXO sugars does N. flavescens utilise?

A

None

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42
Q

What TAXO sugars does N. lactamica utilise?

A

Glucose

Maltose

Lactose

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43
Q

What TAXO sugars does N. sicca utilise?

A

Glucose

Maltose

Sucrose

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44
Q

What Neisseria species ferments glucose only?

A

Gonorrhoeae

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45
Q

What Neisseria species ferments none of the TAXO sugars ?

A

N. flavescens

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46
Q

What Neisseria species ferments glucose and maltose?

A

N. meningitidis

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47
Q

What Neisseria species ferments glucose, maltose and lactose?

A

N. lactamica

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48
Q

What Neisseria species ferments glucose, maltose and sucrose?

A

N. sicca

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49
Q

What is a positive result for the TAXO sugar test?

A

Yellow colour -> colour change from red to yellow upon addition of the phenol red indicator

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50
Q

What is a negative result for the TAXO sugar test

A

Red colour -> no colour change upon addition of the phenol red indicator

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51
Q

What is a positive catarrhalis disc test?

A

Blue-green colour development

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52
Q

What is a negative catarrhalis disc test?

A

No colour development within 2 minutes

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53
Q

What species will give a positive catarrhalis disc test?

A

M. catarrhalise

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54
Q

What species will give a negative catarrhalis disc test?

A

Neisseria species

55
Q

What is a positive lecithinase reaction on PEMBA agar?

A

Zone of clearance around colonies

56
Q

What is a negative lecitihinase reaction on PEMBA agar?

A

No zone of clearance around colonies

57
Q

What is a positive mannitol fermentation reaction on PEMBA agar?

A

Yellow colonies

58
Q

What is a negative mannitol fermentation reaction on PEMBA agar?

A

Blue colonies

59
Q

What bacillus species will grow on PEMBA agar as blue colonies with a zone of clearance?

A

B. cereus or B. thuringenesis

60
Q

What bacillus species will grow on PEMBA agar as blue colonies with a variable narrow zone of clearance?

A

B. anthracis

61
Q

What bacillus species will grow on PEMBA agar as yellow colonies with no zone of clearance?

A

B. subtilis

62
Q

How does B. cerues and B. thuringensis look on PEMBA agar?

A

Blue colonies with a zone of clearance

63
Q

How does B. anthracis look on PEMBA agar?

A

Blue colonies with a narrow zone of clearance

64
Q

How does B. subtilis look on PEMBA agar?

A

Yellow colonies with no zone of clearance

65
Q

What exactly does motility look like?

A

Movement in a definite direction

66
Q

What species of bacillus are motile

A

B. cerues
B. thuringenesis
B. subtilis

67
Q

What species of bacillus are non motile

A

B. anthracis

68
Q

What is a positive trehalose test

A

Yellow colour change

69
Q

What is a negative trehalose test

A

No colour change = pink colour

70
Q

What is a positive urease test

A

Pink colour change

71
Q

What is a negative urease test

A

No colour change = yello

72
Q

What species of Corynebacteria will give a positive trehalose and positive urease test?

A

C. ulcerans

73
Q

What species of Corynebacteria will give a negative trehalose and a negative urease test?

A

C. diptheria

74
Q

What species of Corynebacteria will give a negative trehalose and positive urease

A

C. pseudotuberculosis

Diptheroids

75
Q

How will C. ulcerans look in the trehalose and urease tests?

A

Trehalose = yellow = positive
Urease = pink = positive

76
Q

How will C. diptheria look in the trehalose and urease tests?

A

Trehalose = pink = negative
Urease = yellow = negative

77
Q

How will C. pseudotuberculosis and the diptheroids look on the trehalose and urease tests?

A

Trehalose = pink = negative
Urease = pink = positive

78
Q

What species will grow on Tinsdale agar?

A

Only Corynebacteria will grow on Tinsdale

79
Q

How does C. diptheriae/C. ulcerans appear on Tinsdale medium?

A

Black colonies with brown halos

80
Q

How do the diptheroids look on Tinsdale medium

A

Dark brown colonies without halos

81
Q

What species grows on Tinsdale medium with black colonies and no discoloration of the medium?

A

Diptheroids such as haemophilus, klebsiella, neisseria, staphylococcus and streptococccus

82
Q

What species of Corynebacteria grows on Tinsdale medium with black colonies and brown halos/discoloration of medium?

A

C. diptheria
C. ulcerans

83
Q

What is a positive result for lactose fermentation in the lactose-gelatin tubes?

A

Yellow colour

84
Q

What is a negative result for lactose fermentation in the lacctose-gelatin tubes?

A

Red colour

85
Q

What is a positive result for gelatinase in the lactose-gelatin tubes?

A

Liquid formation

86
Q

What is a negative result for gelatinase in the lactose-gelatin tubes?

A

Gel formation

87
Q

How does C. perfringens appear in the lactose-gelatin tubes

A

Yellow liquid

Lactose fermentation - positive = yellow
Gelatinase - positive = liquid

88
Q

How does C. tetani/ C. difficile appear in the lactose-gelatin tubes?

A

Red gel

Lactose fermentation - negative = red
Gelatinase - negative = gel

89
Q

How does C. botulinum/ C. sporogenes appear in the lactose-gelatin tubes?

A

Red liquid

Lactose fermentation - negative = red
Gelatinase - positive = liquid

90
Q

Which species will appear as a yellow gel in the lactose-gelatin tubes?

A

E. coli

91
Q

Which species will appear as a yellow liquid in the lactose-gelatin tubes?

A

C. perfringens

92
Q

Which species will appear as a red gel in the lactose gelatin tubes

A

C. tetani
C. difficile

93
Q

Which species will appear as a red liquid in the lactose gelatin tubes?

A

C. botulinum and C. sporogenes

94
Q

What is a positive lecithinase result for the egg yolk agar

A

opaque diffuse zone

95
Q

What is a negative lecithinase result for the egg yolk agar

A

No opaque diffuse zone

96
Q

What is a positive lipase result for the egg yolk agar?

A

Pearly/shiny layer

97
Q

What is a negative lipase result for the egg yolk agar?

A

Absence of pearly/shiny layer

98
Q

Which species will give a positive lecithinase but a negative lipase result on egg yolk agar?

A

C. perfringens

99
Q

Which species will give a negative lecithinase and negative lipase result on egg yolk agar?

A

C. tetani
C. difficile

100
Q

Which species will give a variable amount of lecithinase activity and a positive lipase result on egg yolk agar?

A

C. botulinum

101
Q

Which species will give a negative lecithinase and a positive lipase result on egg yolk agar?

A

C. sporogenes

102
Q

What is a positive Naglar test result

A

Disappearance of opacity

103
Q

What is a negative Naglar test result

A

No disappearance of opacity

104
Q

How does B. fragilis appear on the MID8 mastring test?

A

Erythromycin = Occassionally susceptible
Rifampicin = Susceptible
Colistin sulphate = Ocassionally resistant
Penicillin = Resistant
Kanamycin = Resistant
Vancomycin = Resistant

105
Q

What growth factors does H. influenzae need?

A

X factor and V factor

106
Q

What growth factors does H. parainfluenzae need?

A

V factor only

107
Q

What growth factors does H.ducreyi need?

A

X factor only

108
Q

What growth factors does H. aegyptius need?

A

X factor and V factor

109
Q

What growth factors does H. aphrophilus need?

A

Variable growth with X only

110
Q

What haemophilus species need both X and V factors to grow

A

H. influenzae
H. aegyptius

111
Q

What haemophilus species need V factor only to grow

A

H. parainfluenzae

112
Q

What haemophilus species need X factor only to grow

A

H. ducreyi
H. aphrophilus (variable growth with X only)

113
Q

What is a positive result for King’s A Medium

A

P. aeruginosa grows at 37 degrees with green fluorescence

114
Q

What is a negative result for King’s A Medium

A

P. fluorescence will grow but won’t be fluorescent green

E.Coli will not grow at all

115
Q

What does pink/red on Brilliance chromagar suggest?

A

E. Coli

116
Q

What does turquoise/blue-green indicate on brilliance chromagar?

A

Enterococcus species

117
Q

What does dark blue/purple indicate on brilliance chromagar

A

Colliforms -> enterobacteroides

118
Q

What does brown halos indicate on brilliance chromagar

A

Proteus
Morganella
Providencia

119
Q

What does brown/green translucent indicate on brilliance chromagar

A

Pseudomonas

120
Q

What does non pigmented indicate on brilliance chromagar

A

Staphylococci
Streptococci

121
Q

What does pink indicate on brilliance chromagar

A

S. saprophyticus

122
Q

What is a positive citrate test

A

Colour change from green to blue

123
Q

What is a negative citrate test

A

No colour change - green colour

124
Q

What is a positive indole test?

A

Cherry red colour development after addition of 8 drops kovaks reagent

125
Q

What is a negative indole test?

A

No colour development after addition of Kovaks reagent

126
Q

What is a positive MR test?

A

Maintenance of red colour following addition of MR solution

127
Q

What is a negative MR test?

A

A yellow colour persists following addition of MR solution

128
Q

What is a positive VP test?

A

Red colour development after addition of the VP reagent 1 and 2

129
Q

What is a negative VP test?

A

No red colour development after addition of the VP reagents 1 and 2

130
Q

What is a positive dulcitol test?

A

Colour change from pink to yellow

131
Q

What is a negative dulcitol test?

A

No colour change -> pink colour

132
Q

What is a positive decarboxylase test?

A

Purple colour

133
Q

What is a negative decarboxylase test?

A

Yellow colour