Laboratory Diagnosis of Enterobacteriaceae Flashcards
1
Q
identify
- BAP: shiny, opaque, smooth, nonhemolytic
- MAC: NLF/LF
A
Plesiomonas shigelloides
2
Q
identify
produces flat colonies with jagged edges on MAC
A
Shigella sonnei
3
Q
identify
TSI contains 10 parts (?) : 10 parts (?) : 1 part (?) and (?)
A
- lactose
- sucrose
- glucose
- peptone
4
Q
identify
This test is used to determine the ability of an organism to utilize sodium citrate as its only carbon source and inorganic ammonium salts as its only nitrogen source
A
citrate utilization
5
Q
identify
- MAC: NLF
- HE: colorless
- XLD: red or yellow
A
Hafnia alvei
6
Q
identify
Christensen’s citrate medium incorporates phenol red (as the Ph indicator) and organic nitrogen.
At an alkaline pH, the indicator turns from yellow to (?)
citrate utilization
A
pink
7
Q
identify
- Production of hydrogen sulfide (H2S)
- Salmonella spp. appear as brown to black precipitate
isolation of Salmonella spp. & Shigella spp.
A
Bismuth sulfite agar
8
Q
identify
- H2S (TSI agar): (-)
- urease: (-)
- indole: (+/-)
- methyl red: (+)
- voges-proskauer: (-)
- citrate (simmons): (-)
- KCN: (-)
- phenylalanine deaminase: (-)
- mucate: (d)
- mannitol: (+/-)
A
Escherichieae
9
Q
identify
- Shigella spp. appear colorless
- Salmonella spp. colorless with a black center
isolation of Salmonella spp. & Shigella spp.
A
Salmonella-Shigella agar (SS)
10
Q
identify
used to differentiate sorbitolnegative E. coli O157:H7 from other strains of E. coli
A
MacConkeysorbitol agar (MAC-SOR)
11
Q
identify
reagents
rapid spot indole test
A
- kovac’s reagent
- p-dimethylaminobenzaldehyde Bio Merieux (or equivalent)
12
Q
identify
This test is helpful in initial differentiation of Proteus, Morganella, and Providencia organisms, which are positive
A
phenylalanine deaminase (PAD)
13
Q
identify
may be red pigmented, especially if plate is left at 25°C on MAC
A
Serratia marcescens
14
Q
identify
Bacteria that can grow on this medium turn the bromthymol blue indicator from green to (?)
citrate utilization
A
blue
15
Q
identify
methyl red test positive:
(?) color at surface of the medium
MR-VP medium/MR-VP broth
A
red
16
Q
identify
- H2S (TSI agar): (-)
- urease: (-/+)
- indole: (-)
- methyl red: (-)
- voges-proskauer: (+)
- citrate (simmons): (+)
- KCN: (+)
- phenylalanine deaminase: (-)
- mucate: (+/-)
- mannitol: (+)
A
Klebsielleae
17
Q
identify
Rapid development of a (?) color on the filter paper, usually within 30 seconds, is indicative of a positive test result.
rapid spot indole test
A
bright pink-red
18
Q
identify
(?) medium is an alternative test medium
citrate utilization
A
Christensen’s citrate
19
Q
identify
- MAC: NLF
- HE: green, H2S production
- XLD: red with H2S
A
Salmonella spp.
20
Q
identify
colonies on SBA are pinpoint at 24 hours but exhibit a rough, cauliflower appearance at 48 hours
A
Y. pestis
21
Q
identify
- safety pin appearance
- bipolar appearnce
A
Yersinia spp
22
Q
identify
- H2S (TSI agar): (-)
- urease: (+)
- indole: (+/-)
- methyl red: (+)
- voges-proskauer: (-)
- citrate (simmons): (-)
- KCN: (-)
- phenylalanine deaminase: (-)
- mucate: (none)
- mannitol: (+)
A
Yersiniae
23
Q
identify
Simmons Citrate Agar contains (?)
A
ammonium dihydrogen phosphate
24
Q
identify
methyl red test negative:
(?) color at surface of the medium
MR-VP medium/MR-VP broth
A
yellow
25
# identify
negative
| voges-proskauer test|results
Escherichia coli
26
# identify
* **MAC**: NLF
* **HE**: green
* **XLD**: colorless
Shigella spp.
27
# identify
**K/NC**
(glucose, lactose, and sucrose non utilizer)
| TSI agar|results
Pseudomonas aeruginosa
28
# identify
* **MAC**: most LF, some NLF, generally flat, dry, pink colonies with a surrounding darker pink area of precipitated bile salts
* **HE**: yellow
* **XLD**: yellow
Escherichia spp.
29
# identify
A **(?)** color denotes a **negative indole test** after addition of Kovacs Reagent
| SIM (sulfide, indole, motility) medium|results
yellow
30
# identify
* **H2S (TSI agar):** (+/-)
* **urease**: (+/-)
* **indole**: (+/-)
* **methyl red:** (+)
* **voges-proskauer**: (-)
* **citrate (simmons)**: (d)
* **KCN**: (+)
* **phenylalanine deaminase**: (+)
* **mucate**: (-)
* **mannitol**: (-/+)
Proteeae
31
# identify
Decarboxylates or deaminates lysine and forms hydrogen sulfide (H2S)
lysin iron agar
32
# identify
used as the **positive control**
| rapid spot indole test|quality control
E. coli ATCC 25922
33
# identify
A **negative reaction** is evidenced by no growth or growth with the medium remaining **(?)** in color
| simmons citrate agar
green
34
# identify
A **positive test for indole** is denoted when a **(?)** color band is formed at the top of the medium after addition of Kovacs Reagent
| SIM (sulfide, indole, motility) medium|results
pink to red
35
# identify
The production of **(?)** color indicates that indole has been produced from the amino acid tryptophan
| kovac's indole test
red
36
# identify
**R/A**
(lysine deamination and glucose fermentation)
Proteus vulgaris
37
# identify
* **H2S (TSI agar):** (+)
* **urease**: (-)
* **indole**: (+)
* **methyl red:** (+)
* **voges-proskauer**: (-)
* **citrate (simmons)**: (-)
* **KCN**: (-)
* **phenylalanine deaminase**: (-)
* **mucate**: (-)
* **mannitol**: (-)
Edwardsielleae
38
# identify
* **Salmonella spp.** colorless to red with black center
* **Shigella spp.** colorless to red
* Other **Enterobacteriaceae** Yellow
| isolation of Salmonella spp. & Shigella spp.
Xylose-lysine-deoxycholate agar (XLD)
39
# identify
a **selective medium** specifically used for the isolation of **Y. enterocolitica**
Cefsulodin-irgasan-novobiocin agar (CIN)
40
# identify
Cultures to be tested must be grown on media containing tryptophan.
Trypticase soy agar (TSA) with or without sheep red blood cells is suitable
rapid slot indole test
41
# identify
**K/A**
(glucose fermentation)
| lysin iron agar|result
Shigella flexneri
42
# identify
reagents
| nitrate reduction test
solution A
* sulfanilic acid
* acetic acid
solution B
* β-Naphthylamine
* acetic acid
* glacial acetic acid
* distilled water
43
# identify
voges-proskauer test:
A **positive** reaction is indicated by the development of a distinct **(?)** color which occurs within 5 minutes
| MR-VP medium/MR-VP broth
red
44
# identify
**positive**
(Change in color of slant from light orange to magenta)
| urea hydrolysis|results
Proteus vulgaris
45
# identify
positive
| voges-proskauer test|results
Enterobacter cloacae
46
# identify
N,N-dimethyl-α-naphthylamine and sulfanilic acid is added
**(?)** color indicates the presence of nitrite
| nitrate and nitrite reduction
red
47
# identify
indole negative
| kovac's indole test|results
Pneumoniae
48
# identify
Salmonella spp. appear as **white to pink or red colonies** surrounded by a **bright halo**
| isolation of Salmonella spp. & Shigella spp.
brilliant green agar
49
# identify
* **MAC**: NLF, may swarm, foul smell
* **HE**: colorless
* **XLD**: yellow or colorless, with/without H2S
Proteus spp.
50
# identify
* Gram negative bacilli
* Coccobacilli or straight rods with rounded ends
enterobacteriaceae
51
# identify
A **negative motility test** is indicated by growth confined to the **(?)**
| SIM (sulfide, indole, motility) medium|results
stab line
52
# identify
Cloudiness spreading from the inoculation line is positive for **(?)**
| sulfide-indole-motility agar
motility
53
# identify
Wright or Giemsa stain of lesions infected with **(?):**
DONOVAN Body are blue rod with prominent polar granules, giving rise to the safety-pin appearance, surrounded by a large, pink capsule.
Klebsiella granulomatis
54
# identify
A **positive motility test** is indicated by a **(?)** flaring from the line of inoculation
| SIM (sulfide, indole, motility) medium|results
diffuse zone of growth
55
# identify
Urea Agar contains **(?)** and **(?)** as the pH indicator
* urea
* phenol red
56
# identify
may be used as enrichment for the isolation of **Shigella**
* Gram-negative broth (GN)
* Selenite broth (SEL)
57
# identify
* **MAC**: LF, mucoid
* **HE**: yellow
* **XLD**: yellow
Klebsiella spp.
58
# identify
* **MAC**: NLF
* **HE**: colorless
* **XLD**: yellow or colorless
Providencia spp.
59
# identify
A **positive** **H2S test** is denoted by a **(?)** of the medium along the line of inoculation.
| SIM (sulfide, indole, motility) medium|results
blackening
60
# identify
* **H2S (TSI agar):** (+/-)
* **urease**: (+/-)
* **indole**: (-/+)
* **methyl red:** (+)
* **voges-proskauer**: (-)
* **citrate (simmons)**: (+)
* **KCN**: (+/-)
* **phenylalanine deaminase**: (-)
* **mucate**: (none)
* **mannitol**: (+)
Citrobacteriaceae
61
# identify
positive
| methyl red test|results
Escherichia coli
62
# identify
**selective agars** in addition to SBA, chocolate, and MacConkey agars
* Hektoen enteric agar (HE)
* xylose-lysine-deoxycholate agar (XLD)
* Salmonella-Shigella agar (SS)
63
# identify
**negative**
[No color change (agar slant and butt remain light
orange)]
| urea hydrolysis
Escherichia coli
64
# identify
This test is used to determine the ability of an organism to produce the enzyme urease, which hydrolyzes urea
urea hydrolysis (Christensen's method)
65
# identify
* **MAC**: NLF, may be colorless to peach
* **HE**: salmon
* **XLD**: yellow or colorless
Yersinia spp.
66
# identify
indole positive
| kovac's indole test|results
Escherichia coli
67
# identify
A **positive reaction** is indicated by growth with development of a **(?)** color reaction within the medium
| simmons citrate agar
deep blue
68
# identify
culture medias:
* SBA
* Chocolate agar
* MacConkey agar
69
# identify
**Broth cultures of Y. pestis** exhibit a characteristic **"(?)"** in which clumps of cells adhere to one side of the tube
stalactite pattern
70
# identify
The production of H2S is indicated by a black precipitate, and a pink to red color after the addition of Kovac’s reagent is positive for **(?)**
| sulfide-indole-motility agar
indole
71
# identify
The **(?)** is more sensitive than Kovac’s reagent and is preferred with nonfermentative bacteria
| indole production
Ehrlich method
72
# identify
**Selective enrichment** for the growth of Salmonella spp.
| isolation of Salmonella spp. & Shigella spp.
Selenite broth
73
# identify
Organisms capable of hydrolyzing urea form ammonia as a byproduct, thus turning the medium alkaline.
The pH indicator turns from pale yellow to **(?)** in color in these conditions
| urea agar slant
pink-red
74
# identify
A **(?)** color develops if the test result is **positive for nitrate reduction**
| nitrate reduction test|results
red
75
# identify
**A/A**
(glucose, sucrose, and/or lactose fermenter)
| TSI agar|results
Escherichia coli
76
# identify
A **negative** **H2S test** is denoted by the absence of **(?)**
| SIM (sulfide, indole, motility) medium|results
blackening
77
# identify
used as the **negative control**
| rapid spot indole test|quality control
Pseudomonas aeruginosa ATCC 27853
78
# identify
* **MAC**: late LF,
* **HE**: colorless
* **XLD**: yellow or colorless
Serratia spp.
79
# identify
**(?)** are blue rod with prominent polar granules, giving rise to the safety-pin appearance, surrounded by a large, pink capsule
DONOVAN body
80
# identify
Media that are highly selective for the isolation of **Salmonella spp.**
* CHROM agar Salmonella
* brilliant green agar
* bismuth sulfite agar
81
# identify
reagents
| kovac's indole test
* Amyl/isoamyl alcohol
* p-Dimethylaminobenzaldehyde
* Hydrochloric acid
82
# identify
Approximately 5 drops of Kovac’s reagent is added directly to the broth culture.
The tube is shaken, and if indole is present, a **(?)** color develops
| sulfide-indole-motility agar
red
83
# identify
**K/K H2S+**
(lysine decarboxylation and no fermentation of glucose, black precipitate in the butt)
| lysin iron agar|results
Salmonella typhimurium
84
# identify
No color change indicates a **(?)** test result
| rapid spot indole test
negative
85
# identify
one of the degradation products of the amino acid tryptophan
| sulfide-indole-motility agar
indole
86
# identify
**negative**
(absence of growth)
| citrate utilization|results
Escherichia coli
87
# identify
* **MAC**: LF, may be mucoid
* **HE**: yellow
* **XLD**: yellow
Enterobacter spp.
88
# identify
**Lactose fermenter**, forms **blueblack** with a **metallic green** sheen
E. coli
89
# identify
Hydrolysis of urea produces **ammonia and CO2**
The formation of ammonia alkalinizes the medium, and the pH shift is detected by the color change of phenol red from **(?)** at pH 6.8 to **(?)** at pH 8.1
| urea hydrolysis
* light orange
* magenta
90
# identify
**(?)** and **(?)** serve as indicators of acidification and H2S formation, respectively
| TSI agar
* phenol red
* ferrous sulfate
91
# identify
negative
| methyl red test|results
Enterobacter cloacea
92
# identify
Bromothymol Blue is (?) at pH **(<7.0)**
and (?) at pH **(>7.6)**
| citrate utilization
* green
* blue
93
# identify
* **MAC**: NLF
* **HE**: colorless
* **XLD**: red or colorless
Morganella spp.
94
# identify
* **MAC**: late LF (after 48 hr), colonies are light pink
* **HE**: colorless
* **XLD**: red, yellow, or colorless, with/without H2S
Citrobacter spp.
95
# identify
**K/A H2S+**
(glucose fermentation only, black precipitate in the butt)
| TSI agar|results
Salmonella typhi
96
# identify
* **MAC**: NLF
* **HE**: colorless
* **XLD**: red, yellow, colorless, with/without H2S
Edwardsiella spp.
97
# identify
stained with **Wayson stain** or **Methylene Blue stain**
Yersinia spp.
98
# identify
After incubation, α-naphthol is added first as a catalyst or color intensifier. Next, 40% potassium hydroxide (KOH) or sodium hydroxide (NaOH) is added, and the tube is gently shaken to increase oxygenation.
Under these conditions, acetoin is oxidized to diacetyl. Diacetyl in the presence of KOH and α-naphthol forms a **(?)** complex.
| voges-proskauer test
red
99
# identify
After incubation, approximately half the broth is transferred to a clean dry tube for the VP test
A **(?)** color develops after addition of the pH indicator MR
MR-negative cultures remain **(?)** after addition of the pH indicator (pH 6.0)
| methyl red test
* red
* yellow
100
# identify
A rapid indole test using p-dimethylaminocinnamaldehyde:
bacterial colonies are **smeared onto filter paper** that has been moistened with p-dimethylaminocinnamaldehyde.
The formation of a **(?)** color within 2 minutes is a positive reaction
| indole production
blue green
101
# identify
**positive**
(Growth on the medium, with or without a change in the color of the indicator. Growth usually results in the bromthymol blue indicator, turning from green to blue)
| citrate utilization|results
Klebsiella pneumoniae
102
# identify
* **H2S (TSI agar):** (+)
* **urease**: (-)
* **indole**: (-)
* **methyl red:** (+)
* **voges-proskauer**: (-)
* **citrate (simmons)**: (+)
* **KCN**: (-)
* **phenylalanine deaminase**: (-)
* **mucate**: (d)
* **mannitol**: (+)
Salmonelleae
103
# identify
No color production is a **(?)** test result and should be confirmed by the addition of zinc dust.
If unreduced nitrate is present, a **(?)** color develops, confirming the negative test result.
If **no color change occurs**, a complete reduction has occurred, and the test result is **(?)**
| nitrate reduction test|results
* negative
* red
* positive
