Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

[9a] MODULE 6 UNIT 1: Enterobacteriaceae and Other Related Enterobacteria > LABORATORY > Flashcards

LABORATORY Flashcards

1
Q

Specimen for diagnosing Enterobacteriaceae and Other Related Enterobacteria

A

Urine, blood, pus, spinal fluid, sputum

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

Gram Negative Enterobacteriaceae

A 
Escherichia coli
Shigella dysenteriae
Salmonella typhi
Klebsiella pneumoniae
Proteus vulgaris
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Cultural Method for Enterobacteriaceae spp

A 
BAM
MAC 
SSA
EMB
Broth culture
35-37 oC
24-48 hours
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

On MAC:

Typical strong lactose fermenters produce

Slow or weak lactose fermenters produce

Non-lactose fermenters produce

A

red colonies surrounded by a zone of precipitated bile.

light pink colonies or colonies that are clear at the periphery and have pink centers.

colorless colonies or transparent colonies

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

On EMB:

Typical strong lactose fermenters produce

Slow or weak lactose fermenters produce

Non-lactose fermenters produce

A

black with metallic sheen

pink to purple colonies

colorless colonies or transparent colonies

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

On SSA:

Slight growth of lactose fermenters that produce

Salmonella and Proteus colonies are

Shigella colonies are

A

pink or red colonies.

colorless with black centers.

colorless with no blackening.

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

stabbing the butt (or deep) to within 2-3 mm

streak over the agar surface (or slant) with a back-and-forth motion

A

Triple Sugar Iron Agar Reactions

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

stabbing to two-thirds of the distance to the

bottom in the center of the butt (or deep).

A

Sulfide-Indole-Motility Test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

stabbing the butt (or deep) twice

streak over the agar surface (or slant).

A

Lysine Iron Agar Reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Incubation period for TSIA, SIM Test, and LIA Reactions

A

35-37oC for 18-24 hours

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

indicated by the retention of the original red color of the medium

A

Alkalinization or nonfermentation of the carbohydrates

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

designates alkaline reaction

A

“K”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

indicated by a change in the color of the medium from red to yellow

A

Acid production from fermentation of carbohydrate(s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

designates acidic reaction

A

“A”

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

indicated by gas bubbles or spitting of the agar in the butt portion

A

Gas production

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

indicated by a black discoloration of the medium which first appears or remains confined in the butt portion

A

Hydrogen sulfide (H2S) production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

alkaline slant and butt, no gas and H2S production

alkaline slant, acid butt, with gas and H2S production

acid slant and butt, with gas, no H2S production

A

K/K

K/Ag + H2S

A/Ag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Diffuse growth outward from the stab line or turbidity throughout the medium

A

Motility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Blackening of the medium (or along the stab line)

A

H2S production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

To detect indole production, add 3-4 drops of Ehrlich’s or Kovac’s reagent, and observe for a pink to red color

A

Indole production

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

is detected in the butt by an alkaline (purple) slant

A

Lysine decarboxylation

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

is detected by a red slant.

A

Lysine deamination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

detected by formation of a black precipitate.

A

Hydrogen sulfide (H2S) production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

alkaline slant and butt, and NO H2S production

alkaline slant and butt butt, and H2S production

Red slant, acid butt, and NO H2S production

alkaline slant, acid butt, and NO H2S production

alkaline slant, acid butt, and H2S production

A

K/K

K/K + H2S

R/A

K/A + H2S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

INDOLE TEST: Reagent

A

15 drops of Ehrlich’s + 1 ml of xylene or chloroform

Kovac’s reagent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

INDOLE TEST: Positive result

A

Bright fuschia red color

*at the interface of the reagent and the broth (or xylene layer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

INDOLE TEST: Negative result

A

Yellow color or no color change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

METHYL RED TEST: Reagent

A

5 drops of methyl red indicator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

METHYL RED TEST: Positive result

A

Red color on the surface of the medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

METHYL RED TEST: Negative result

A

Yellow to orange color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

VOGES-PROSKAUER TEST

A
  1. 6 ml of 5% alpha-naphthol

0. 2 ml of 40% KOH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

VOGES-PROSKAUER TEST: Positive result

A

Red color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

VOGES-PROSKAUER TEST: Negative result

A

Yellow color or no color change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

SIMMON’S CITRATE UTILIZATION TEST: Reagent

A

no indicator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

SIMMON’S CITRATE UTILIZATION TEST: Positive result

A

Prussian blue or deep blue color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

SIMMON’S CITRATE UTILIZATION TEST: Negative result

A

No color change (retention of green color)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

The presence of large capsules, which can be observed as colorless to light pink halo around the bacilli, is suggestive of

A

Klebsiella species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

A basic fuchsin-methylene blue, ethyl alcohol phenol microscopic staining procedure.

A

Wayson staining for Yersinia species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Useful alternative for Gram staining.

A

Wayson staining for Yersinia species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

show bipolar purple staining with a central vacuole giving a characteristic “safety pin” appearance.

A

Yersiniae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Used as an enrichment medium for the isolation of Salmonella from feces, urine, water, food and other materials.

A

Selenite broth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Selenite broth: inhibitor

A

Sodium selenite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Incubation for Selenite Broth - because coliforms or other intestinal flora may overgrow the pathogens within a few hours.

A

8-12 hours at 35 oC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Overheating of Selenite Broth may produce a visible [?], making it unsatisfactory for use.

A

precipitate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Used as an enrichment medium for the recovery of Salmonella and Shigella from clinical and nonclinical specimens.

A

GN (Hajna) broth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

[?], in a higher concentration than glucose, enhances the growth of Salmonella and Shigella.

A

Mannitol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

GN (Hajna) broth: inhibitor

A

Sodium citrate and sodium desoxycholate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Incubation for GN (Hajna) broth - because of relatively low concentration of desoxycholate, it is less inhibitory to E. coli and other coliforms.

A

4-6 hours at 35 oC,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Used as a selective enrichment for Salmonella species.

A

Tetrathionate broth, with iodine-iodide solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

formed in the medium by the addition of iodine-iodide solution

A

tetrathionate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

tetrathionate broth: inhibitor

inhibits the normal intestinal flora of fecal specimens.

A

bile salt, tetrathionate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Incubation for Tetrathionate broth, with iodine-iodide solution

A

18-24 hours at 35 oC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

heat the broth base to [?], add the

iodine solution

A

boiling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Colonies are usually large, white or gray, smooth, shiny, circular, raised colonies which may or may not be hemolytic.

A

Blood agar medium (BAM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Used for selective isolation of G- enteric bacilli by incorporation of agent/s inhibitory to G+ bacteria; may be slightly selective, moderately selective, or highly selective.

A

SELECTIVE MEDIA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Are also generally differential plating media to distinguish between coliforms (lactose-fermenting) from noncoliforms (non-lactosefermenting) enteric bacilli

A

SELECTIVE MEDIA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

MacConkey Agar (MAC): inhibitor

A

Crystal violet dye and bile salts i

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

MAC: pH indicator

A

neutral red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

is a selective and differential medium for the detection of sorbitol-nonfermenting Escherichia coli serotype O157:H7 associated with hemorrhagic colitis that results from the action of a shiga-like toxin
(SLT)

A

MacConkey Agar with Sorbitol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

On standard MacConkey Agar containing [?], this strain is indistinguishable from other lactose-fermenting E. coli.

A

lactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Unlike most E. coli strains, E. coli O157:H7 ferments [?] slowly or not at all.

A

sorbitol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

efficacy of MacConkey Agar containing sorbitol instead of lactose as a [?] for the detection of E. coli O157:H7 in stool cultures was determined.

A

differential medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Salmonella Shigella Agar (SSA): inhibitor

A

Bile salt salts, brilliant green and citrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

SSA: pH indicator

A

neutral red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

SSA: Sulfur Source

A

Sodium thiosulfate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

SSA: H2S indicator

A

ferric citrate - black precipitate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

During preparation, heat to boiling to completely dissolve the agar.

A

SSA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

XLD: inhibitor

A

Bile salts (sodium desoxycholate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

XLD: pH indicator

A

phenol red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

is fermented by practically all enterics except for the shigellae. This property enables differentiation of Shigella.

A

Xylose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

initially produce yellow colonies due to xylose fermentation, results in delayed red colonies due to alkaline amines produced.

A

Lysine decarboxylation by Salmonella

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

XLD: H2S indicator

A

Sodium thiosulfate and ferric ammonium citrate - black centers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

HEA: inhibitor

A

Bile salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

HEA: Carbohydrate for acid production

A

Lactose, sucrose (saccharose), and salicin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

acid fuchsin react with bromthymol blue producing a

A

yellow color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

HEA: Sulfur Source

A

Sodium thiosulfate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

HEA: HS2 indicator

A

Ferric ammonium citrate - black centers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

BSA: inhibitors

A

Bismuth sulfite and brilliant green

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

BSA: sulfur source

A

bismuth sulfite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

BSA: H2S production

A

ferrous sulfate - brown to black color with metallic sheen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

BGA: inhibitor

A

Brilliant green dye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

BSA: pH indicator

A

Phenol red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

BSA

produce white to red colonies surrounded by red zones in the medium.

A

Salmonella species (other than S. Typhi/Paratyphi)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

shows no growth to trace growth on BGA.

A

S. typhi/ paratyphi

85
Q

For fecal specimens or rectal swabs: INOCULATING MEDIUM

A

enrichment broth

  • Selenite broth
  • GN broth
86
Q

For fecal specimens or rectal swabs:

incubation for:

  • Selenite broth
  • GN broth
A
  • 35 ± 2°C for 8-12 hours

- 35 ± 2°C for 4-6 hours

87
Q

For fecal specimens or rectal swabs:

  1. Then, subculture into:
A
  • BAM

- One medium from each of the groups of selective media (MAC, EMB; SSA, XLD, HAE; BSA, BGA)

88
Q

For fecal specimens or rectal swabs:

  1. Incubate at
A

35 ± 2°C for 18-24 hours.

89
Q

For non-fecal specimens: INOCULATING MEDIUM

A
  • BAM, and

- MAC or EMB

90
Q

If negative after 24 hours, reincubate an additional [?]. Select suspicious colonies for definitive biochemical or serologic testing.

A

24 hours

definitive biochemical or serologic testing

91
Q

Most common Yersinia species isolated from humans acquired from contaminated food.

A

Yersinia Enterocolitica

92
Q

Specimen for Isolation of Yersinia Enterocolitica

A

Feces

93
Q

Cold enrichment of feces by incubating cultures at [?] in [?] enhances recovery of Y. enterocolitica.

A

4 oC for 1-3 weeks

buffered saline

94
Q

• Subculture for the Isolation of Yersinia Enterocolitica

lactose-negative colonies, flat, colorless, or pale pink, 1-2 mm diameter

A

On MAC

95
Q

• Subculture for the Isolation of Yersinia Enterocolitica

[?]

Fermentation of mannitol in the presence of [?] results in a characteristic [?] colony, colorless with red center. Selective inhibition of G+ and G- bacteria is obtained by means of [?[, [?], and [?]. Supplementation with [?] and [?] improves inhibition of normal enteric bacteria

A

On CIN (Cefsulodin-Irgasan-novobiocin) Agar

  • neutral red
  • “bull’s-eye”
  • crystal violet, sodium desoxycholate and Irgasan (triclosan)
  • cefsulodin and novobiocin
96
Q

The incorporation of four protein derivatives makes TSI nutritionally very rich.

A

beef extract
yeast extract
peptone
proteose peptone

97
Q

The lack of inhibitors permits the of all but the most fastidious bacterial species (excluding the obligate anaerobes). For this reason, TSI agar can be used only when testing a bacterial species selected from a single colony recovered on [?] or [?] agar plates.

A

primary or selective

98
Q

There are two reaction chambers within the same tube.

The [?] exposed throughout its surface to atmospheric oxygen, is aerobic;

the [?], is protected from the air and is relatively anaerobic.

It is important when preparing the media that the slant and the deep are kept equal in length, approximately [?] each

A

upper slant

lower butt or the deep

3 cm (1.5 in.)

99
Q

TSI Reactions: Acid production

[?] are evenly distributed throughout both the slant and butt (deep) portion of the tube. However, glucose is present in a [?] concentration of each of the lactose and sucrose.

A

Glucose, lactose, and sucrose

1/10

100
Q

TSI Reactions: Acid production

The phenol red indicator is yellow below a pH of

A

6.8.

101
Q

TSI Reactions: Acid production

Because the pH of the uninoculated medium is buffered at [?], relatively small quantities of acid production result in a visible color change.

A

7.4

102
Q

The organism ferments glucose, and lactose and/or sucrose producing large amounts of acids, so when examined at the end of 18-24 hours, both the slant and the butt appear yellow.

A

A/A Acid slant / Acid butt

103
Q

Glucose-fermenting organism that cannot utilize lactose and sucrose produces only a small quantity of acid from the [?] concentration of glucose in the medium.

A

0.1%

104
Q

Initially, during the first [?] hours of incubation (i), acid may be sufficient to convert both the deep and the slant color to yellow.

A

8 to 12

105
Q

When the glucose supply is exhausted, and the bacteria begin oxidative degradation of the amino acids within the slant of the tube where oxygen is present.

A

K/A Alkaline slant / Acid butt

106
Q

In the deep (anaerobic portion) of the tube, however, [?] is

insufficient to counteract the acid formed, and the medium remains yellow

A

amino acid degradation

107
Q

This indicates a lack of acid production and failure of the test organism to
ferment any of the sugars present.

A

K/K Alkaline slant / Alkaline butt.

108
Q

This results in the release of [?] that counteract the small quantities of acid present in the slant; by 18 to 24 hours (ii), the entire slant reverts to an alkaline pH, and the color returns to red.

A

amines

109
Q

Presence of cracks in the medium or the “pulling away” of the medium from the walls of the test tube.

A

TSI Reactions

Gas (H2 + CO2) production

110
Q

source of sulfur atoms used for

hydrogen sulfide production

A

Sodium thiosulfate

111
Q 
incorporated in the culture
media then react with
hydrogen sulfide to produce
an insoluble black precipitate
(ferrous sulfide).
A

Iron salts (ferrous sulfate)

112
Q

An acid environment is required for an organism to produce [?] and, therefore, a source of hydrogen ions must be provided. Because the butt of the TSI tubes becomes [?] with glucose fermentation (hydrogen ions increase), the blackening is often first seen or confined there, particularly with non–lactose-fermenting bacteria. Thus, it follows that a black deep should be read as acid even if the usual yellow color is obscured by the black precipitate.

A

hydrogen sulfide

acidic

113
Q

The formula of KIA is similar to TSI, EXCEPT that it lacks [?]and the H2S indicator is [?] instead of ferrous sulfate.

A

sucrose

ferric ammonium citrate

114
Q

When inoculating a series of tubes of differential culture media with an unknown organism, it is important that the [?] be streaked first to prevent carryover of [?] from the other media.

A

citrate medium

proteins or carbohydrates

115
Q

The MR-VP broth culture may be incubated up to

A

2-4 days

116
Q

Because indole is [?], xylene or chloroform should be added to the test medium before adding Ehrlich’s reagent

A

soluble in organic compounds

117
Q

makes extraction step is less critical for Kovac’s reagent

is used for the diluent (ethyl alcohol is used with Ehrlich’s reagent

A

amyl alcohol

118
Q

Because other organisms may produce smaller quantities of acid from the test substrate, an intermediate orange color between yellow and red may develop. This does not indicate a positive test

A

Methyl red (MR) test

119
Q

A positive VP test is represented by the development of a red color in [?] or more after addition of the reagents.

A

15 minutes

120
Q

The test should not be read after standing for over 1 hour because negative VP cultures may produce a [?] potentially resulting in a false
ositive interpretation

Name the test

A

copper-like color

Voges-Proskauer (VP) test

121
Q

sources of carbon used to detect citrate utilization by test bacteria

A

protein and carbohydrates

122
Q

When inoculating a series of tubes of differential culture media with an unknown organism, it is important that the citrate medium be streaked first to prevent [?] from the other media

A

carryover of proteins or carbohydrates

123
Q

Bacteria that possess the enzyme [?] are capable of cleaving tryptophan in tryptone, thereby producing [?]

A

tryptophanase

indole, pyruvic acid, and ammonia.

124
Q

Indole can be detected in tryptophan test medium by observing the development of a red color after adding a solution containing [?] (e.g., Ehrlich’s or Kovac’s reagent)

A

p-dimethylaminobenzaldehyde

125
Q

Bacteria that metabolize [?] formed from the fermentation of glucose via the mixed acid fermentation pathway produce sufficient strong acid to maintain a pH [?], the acid color breakpoint of the [?] indicator to change into a red color

A

pyruvate

below 4.4

methyl red

126
Q

Bacteria that metabolize pyruvate formed from the fermentation of glucose via the butylene glycol pathway results in the production of [?], a as the chief end product and form smaller quantities of mixed acids.

A

acetoin (acetyl methyl carbinol)

127
Q

In the presence of atmospheric oxygen and [?], acetoin is converted to [?], and α-naphthol serves as a catalyst to bring out a red complex

A

40% potassium hydroxide

diacetyl

128
Q

Bacteria that utilize [?] as the sole source of carbon can also use [?] as the sole source of nitrogen.

A

citrate

ammonium phosphate

129
Q

Extraction of nitrogen from the ammonium salts in the medium produce [?]and [?], which results in an alkaline pH.

A

sodium bicarbonate (NaHCO3) and ammonia (NH3)

130
Q

Alkalinization in the medium of SCU Test is represented by development of blue color with [?]—yellow [?] and blue [?]—as the indicator

A

bromthymol blue

below pH 6.0

above pH 7.6

131
Q

The ingredients in [?] Medium enable the determination of three activities by which enteric bacteria can be differentiated.

A

SIM

132
Q

are indicators of hydrogen sulfide production of SIM Test

A

Sodium thiosulfate and ferrous ammonium sulfate

133
Q

The ferrous ammonium sulfate reacts with H2S gas to produce [?], a black precipitate.

A

ferrous sulfide

134
Q

The [?] is rich in tryptophan, which is attacked by certain microorganisms resulting in the production of indole.

A

casein peptone

135
Q

The [?] is detected by the addition of chemical reagents following the incubation period.

A

indole

136
Q

detection is possible due to the semisolid nature of the medium.

from the central stab line indicates that the test organism is motile

A

Motility

Growth radiating out

137
Q

Observe for [?] first (and for ?) before the addition of Ehrlich’s or Kovac’s reagent for the detection of indole production.

Such reagent may diffuse into the medium making it [?] which may result in false motility interpretation.

A

motility

H2S production

hazy or cloudy

138
Q

Other media for motility testing:

A

Motilility Test Medium
Motility Indole Ornithine (MIO) Medium
Motility Indole Lysine Sulfide (MILS)
Medium, MIL (Motility-Indole-Lysine)

139
Q

Lysine is the substrate for use in detecting the enzymes, [?] and [?]

A

lysine decarboxylase and lysine deaminase

140
Q

Lysine decarboxylation (LDC+) by bacteria produces alkaline-reacting amine, [?], which causes the pH indicator, [?] — yellow at or [?] and purple [?]. — to change its color to purple.

A

cadaverine

bromocresol purple

below pH 5.2

at or above pH 6.8

141
Q

As decarboxylation only occurs in an acidic medium (?), the culture medium must first be acidified by [?]

A

below pH 6.0

glucose fermentation

142
Q

LDC+ reaction

A

purple butt

143
Q

LDC- reaction

A

yellow butt

144
Q

LDC- bacteria ferment [?] and cause the entire culture medium to turn yellow. On prolonged incubation of the culture medium slant may occur, resulting in a color change to violet

A

glucose

alkalinization

145
Q

[?] are indicators of hydrogen sulfide formation in LIA.

Cultures of [?] that produce hydrogen sulfide cause blackening of the medium

A

Ferric ammonium citrate and sodium thiosulfate

enteric bacilli

146
Q

Lysine deamination (LDA+) gives [?]; this compound reacts with the [?] near the surface of the medium, under the influence of [?], to form reddishbrown compounds

A

ketocarboxylic acid

iron salt

oxygen

147
Q

LDA+ reaction

A

red lant

148
Q

LDA- reaction

A

purple slant

149
Q

LIA reactions

  1. K/K
A

 Escherichia coli
 Klebsiella, Enterobacter (now Klebsiella) aerogenes
 Hafni
 Serrati

150
Q
  1. K/K+ H2S
A

 Salmonella

 Edwardsiella

151
Q
  1. K/A
A

 Shigella
 Citrobacter koseri
 Enterobacter cloacae S. Paratyphi A

152
Q
  1. K/A+ H2S
A

 Citrobacter freundii

153
Q
  1. R/A
A

 Morganella
 Providencia Proteus
o may NOT blacken LIA since acid in the butt may suppress H2S

154
Q
  1. R/A + H2S
A

 Proteus

155
Q

Decarboxylase Test: Medium,Component

A

Moeller Decarboxylase Broth

156
Q

Urease Test: Medium

A

Stuart’s Urea Broth, or Christensen’s Urea Agar

157
Q

Phenylalanine Deaminase (PAD) Test: Medium

A

Phenylalanine Agar

158
Q

Phenylalanine Deaminase (PAD) Test: Reagent

A

10% Ferric Chloride

159
Q

ONPG Test: Reagents

A

a. Sodium phosphate buffer, 1 M, pH 7.0
b. o-Nitrophenyl-β-D-galactopyranoside (ONPG), 0.75 M (Buffered ONPG tablets are commercially available.)
c. Physiologic saline
d. Toluene

160
Q

MUG Test: Reagent

A

4- methylumbelliferyl-ßD-glucuronide

161
Q

Decarboxylases react with the [?] (COOH) group of specific amino acids, forming [?] as a second product.

are the three amino acids routinely tested in the identification of the Enterobacteriaceae

A

carboxyl

alkaline-reacting amines, carbon dioxide

Lysine, ornithine, and arginine

162
Q

The specific amine products are as follows:

Lysine:
Ornithine:
Arginine:

A

Lysine → Cadaverine
Ornithine → Putrescine
Arginine → Citrulline

163
Q

The conversion of [?] to [?] is a dihydrolase, rather than a decarboxylase reaction, in which an [?] group is removed from arginine as a first step.

[?] is next converted to ornithine, which then undergoes decarboxylation to form [?]

A

arginine to citrulline

NH2

Citrulline

putrescine

164
Q

The amino acid to be tested is added to the [?] before inoculation with the test organism.

A

decarboxylase base

165
Q

A control tube, consisting of only the base without the amino acid, must also be set up in parallel. Both tubes are [?] incubated by overlaying with [?]

A

anaerobically

mineral oil

166
Q

During the initial stages of incubation, both tubes turn yellow, owing to the fermentation of the small amount of [?] in the medium. If the amino acid is decarboxylated, [?] are formed and the medium reverts to its original purple color

A

glucose

alkaline amines

167
Q

[?] enzyme possessed by many species of microorganisms hydrolyzes urea with the release of [?]. The ammonia reacts in solution to form [?], (NH4)2CO3, resulting in alkalinization of the medium

A

Urease

ammonia and carbon dioxide

ammonium carbonate

168
Q

is a compound structurally similar to lactose except that the glucose has been replaced by an o-nitrophenyl group

A

o-Nitrophenyl-β-D-galactopyranoside

169
Q

On hydrolysis, through the action of the enzyme [?], ONPG cleaves into two residues, [?]

A

β-galactosidase

galactose and o-nitrophenol

170
Q

is a colorless compound

A

ONPG

171
Q

yellow compound that provides visual evidence of hydrolysis

A

o-nitrophenol

172
Q

Lactose-fermenting bacteria possess both [?], two enzymes required for the production of acid in the lactose fermentation test

A

lactose permease and βgalactosidase

173
Q

The [?] is required for the lactose molecule to penetrate the bacterial cell where the β-galactosidase can cleave the galactoside bond, producing [?]

A

permease

glucose and galactose

174
Q

Non–lactose-fermenting bacteria are devoid of both enzymes and are incapable of producing acid from lactose. Some bacterial species appear to be non–lactosefermenters because they lack [?], but do possess [?] and give a positive ONPG test

A

permease

βgalactosidase

175
Q

So-called late lactose fermenters may be delayed in their production of acid from lactose because of [?]. In these instances, a positive ONPG test may provide a rapid identification of [?]

A

weak permease activity

delayed lactose fermentation

176
Q

is a compound structurally similar to lactose except that the glucose has been replaced by an o-nitrophenyl group

A

Nitrophenyl-β-D-galactopyranoside

ONPG

177
Q

On hydrolysis, through the action of the enzyme [?], ONPG cleaves into two residues, galactose and o
itrophenol

A

β-galactosidase

178
Q

he MUG test is based on the hydrolysis of MUG (4-methylumbelliferyl-βD
lucuronide) by [?], an enzyme produced by most strains of Escherichia coli and other Enterobacteriaceae. The end product of hydrolysis, 4-methylumbelliferone (4- MU), fluoresces blue under [?]

A

β-glucuronidase

long wavelength ultraviolet light

179
Q

From a well-isolated colony of the test
organism previously recovered on primary isolation agar, inoculate two tubes of Møller decarboxylase medium, one containing the [?] to be tested and the other to be used as a control tube devoid of amino acid

A

amino acid

180
Q

Overlay both tubes with sterile mineral oil to cover about [?] of the surface

A

1 cm

181
Q

Incubation for Decarboxylase Test, Urease Test, Phenylalanine Deaminase (PAD)
Test

A

35°C for 18–24 hours

182
Q

Incubation for ONPG Test

A

37°C

183
Q

Incubation for MUG Test

A

35°-37°C for 30 minutes

184
Q

The [?] is inoculated with

a loopful of a pure culture of the test organism; the surface of the agar slant is streaked with the test organism

A

broth medium

185
Q

Inoculate the [?] of the medium with a single colony of the test organism isolated in pure culture of primary plating agar

A

agar slant

186
Q

After incubation, add [?] directly to the surface of the agar. As the reagent is added, the tube is rotated to dislodge the surface colonies

A

4 or 5 drops of the ferric chloride

187
Q

Emulsify a loopful of bacterial growth in [?] to produce a heavy suspension. Bacteria grown in medium containing lactose, such as TSI or KIA, produce optimal results in the ONPG test

A

0.5 mL of physiologic saline

188
Q

Add one drop of [?] to the suspension and vigorously mixed for a few seconds to release the enzyme for the bacterial cells

Add an equal quantity of [?] to the suspension

A

toluene

buffered ONPG solution

189
Q

Place the mixture in a 37°C water bath.

When using ONPG tablets, a loopful of bacterial suspension is added directly to the ONPG substrate resulting from adding [?] to a tablet in a test tube. This suspension is also placed in a 37°C water bath

A

1 mL of distilled water

190
Q

a. Place a MUG disk in an empty sterile petri dish and add a drop of distilled water.
b. Smear 2-3 isolated colonies from
18-24 hour old culture on the disk. c. Place a piece of filter paper saturated with water in the lid of the petri dish to provide humid environment.
d. Incubate aerobically at 35°-37°C
for up to 30 minutes. e. Following incubation, examine the disk for fluorescence using long-wave ultraviolet light (360nm) in a darkened room.

A

Direct disk test

191
Q

a. Add 0.25ml of distilled water to a clean glass tube.
b. Make a heavy suspension with 3-4 colonies of test isolate in the tube. c. Using a forcep, place a MUG disk in the tube and shake vigorously to ensure adequate elution of substrate in the surrounding liquid.
d. Incubate aerobically at 35°-37°C for up to 1 hour.
e. Following incubation, examine the disk for fluorescence using longwave ultraviolet light (360nm) in a darkened room

A

Tube test

192
Q

(+) Purple color

(-) Yellow color

A

Decarboxylase Test

193
Q

(+) Pink-red color

(-) Yellow color

A

Urease Test

194
Q

(+) Green color

(-) No green color

A

Phenylalanine Deaminase (PAD) Test

195
Q

The rate of [?] of ONPG to o-n itrophenol may be rapid for some organisms, producing a visible yellow color reaction within 5–10 minutes

A

hydrolysis

196
Q

Most tests are positive within 1 hour; however, reactions should not be interpreted as negative [?]. The yellow color is usually distinct and indicates that the organism has produced onitrophenol from the ONPG substrate through the action of [?]

A

before 24 hours of incubation

βgalactosidase

197
Q

Alternatively, the disk can be placed directly on the agar surface. In which case, it will not require the addition of water because moisture from the medium will rehydrate the disk

A

Mug Test

198
Q

It is used to screen isolates of Escherichia coli, majority (97%) of which is [?]. Some strains of other organisms other than E. coli (e.g., [?], etc.) also possess the enzyme β-glucuronidase. Hence, the detection of the [?] enzyme is commonly employed in laboratories to identify and differentiate such organisms

A

MUG-positive

Salmonella, Shigella, Staphylococcus, Streptococcus

β-glucuronidase

199
Q

It is used for the detection of E. coli serotype [?] strains. This specific serotype is [?]

A

O157:H7

MUG negative (and sorbitol negative)

200
Q

False negative reactions may be reported when test colonies isolated from media containing [?] are used and hence it may make the interpretation difficult

A

dyes (EMB, MAC)

201
Q

is the only species in the genus Plesiomonas

A

Plesiomonas shigelloides

202
Q

oxidase- and catalase-positive
glucose-fermenting
gram-negative rod with polar flagella

A

Plesiomonas shigelloides

203
Q

Because of phenotypic characteristics, the genus Plesiomonas was formerly in the family [?], however, recent molecular genetic evidence demonstrates that the genus Plesiomonas is most closely related to the genus [?]. Thus it has recently been moved into the [?] family as the only [?] member of the group

A

Vibrionaceae

Proteus

oxidase-positive

204
Q

P. shigelloides is found in aquatic environments that are limited geographically by its minimum growth temperature of [?]. It may be found in fresh and estuarine water, usually in [?] countries

A

8° C

tropical

205
Q

P. shigelloides has emerged as a potential cause of enteric disease in humans, most often after the consumption of [?] or [?]

A

undercooked seafood or untreated water

206
Q

At least three major clinical types of gastroenteritis are caused by Plesiomonas:
‣ The more common [?
‣ A [?] that lasts from 14 days to 2 to 3 months
‣ A more invasive, dysenteric form that resembles [?]

A

watery or secretory diarrhea

subacute or chronic disease

colitis

207
Q

Plesiomonads have also been isolated from a number of extraintestinal infections, most notably

A

meningitis in neonates, septicemia and shock

208
Q

[?] can be a source of infections for veterinarians, zookeepers, aquaculturists, fish handlers, and athletes participating in water-related sports

A

Occupational exposure

209
Q

More serious infections, such as [?] and [?], usually occur only in severely immunocompromised patients or neonates

A

bacteremia and meningitis

[9a] MODULE 6 UNIT 1: Enterobacteriaceae and Other Related Enterobacteria (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions