Biochem Rodriguez Flashcards

1
Q

Laboratory Diapnosia (Entorobacterincerel:
Specimen:

A

stool, rectal swab, blood, urine

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2
Q

Colony morphology:- BAP and CAP

A

large, gray, smooth colonies

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3
Q

Transport media

A

Amies
Cary Blair
Stuart media

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4
Q

•Optimal temp

A

35-37

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5
Q

Optimal temp for

yersinia
E. coli

A

1-5
45-50

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6
Q

Fecal pathogens are generally

A

NLFs

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7
Q

Lactose Fermenters:

A
  1. Enterobacter spp.
  2. Escherichia coli
  3. Klebsiella spp.
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8
Q

Late Lactose Fermenters:

A
  1. Citrobacter spp.
  2. S. sonnei
  3. Hafnia spp
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9
Q

Non-Lactose Fermenters:

A
  1. Edwardsiella spp
  2. Morganella spp.
  3. Proteus spp.
  4. Providencia
  5. Salmonella spp.
  6. Shigella spp.
  7. Yersinia spp.
  8. Erwinia (plant pathogen)
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10
Q

• It is used to differentiate E. coli 0157:H7 (sorbitol -) from other types of E. coli (sorbitol)

A

Mac Conkey -Sorbitol agar

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11
Q

• It is useful to isolate Salmonella spp. and Shigella spp. from heavily contaminated specimens such as stool.
• It contain hiosulfateland ferric ammonium sulfate, which produce blackening of H25-producing bacteria.

A

XLD and HE agars

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12
Q

• = LF yellow colonies (yellow with black center-C. freundil)
• colonies(green with black center-Proteus)
• = NLF red colonies (red with black center-S. enterica)

A

HEA

NLF green

XLD

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13
Q

• It is the confirmatory test for Salmonella and Shigella

A

Serotyping (Slide Agglutination Test)

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14
Q

Serotyping

• Preferred media for testing:

• The use of_____-containing media (Mac Conkey or TSI) for testing can cause the organism to autoagglutinate.

A

5% sheep’s BAP

sugar

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15
Q

Serogroups of Shigella:
1. Serogroup A -
2. Serogroup B -
3. Serogroup C -
4. Serogroup D -

A

S. dysenteriae

S. flexneri

S. boydii

S. sonnei (only one serotype)

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16
Q
  • facilitates the entry of the lactose molecule through the bacterial cell wall.
A

B-galactoside permease

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17
Q

hydrolyze lactose into glucose and galactose.

A

B-galactosidase

18
Q

• Used to determine whether a Gram-negative rod utilizes glucose and lactose or sucrose fermentatively and forms hydrogen sulfide (H25).
• ratio of sugars in TSI.

A

10:10:1 (lactose:sucrose:glucose)

19
Q

TSI

• pH indicator: pH indicator
H2Sindicators:

A

phenol red

ferrous sulfate and sodium thiosulfate

20
Q

Sulfide Indole Motility Test
tryptophan -
→ indole
• Indole production is used to determine the ability of an organism to split tryptophan to form the compound indole.
• (+) sulfide:
• (+) indole: after the addition of Kovac’s reagent.)
• (+) motility:/hazy appearance.

A

black color formation

pink to wine colored ring

spread out/movement away from the stab line

21
Q

Citrate Utilization
It is used to determine the ability of an organism to utilize sodium citrate is its
only carbon source and inorganic ammonium salts|as its only nitrogen source.
• (+) reaction:
• pH indicator:

A

from gree to blue colored slant

bromthymol blue

22
Q

• Klebsiella and Enterobacter =
• Escherichia and Edwardsiella =

A

citrate (+)

citrate (-)

23
Q

Lysine Iron Agar Test
• It is used to determine whether a Gram-negative rod decarboxylates or
deaminates lysine and forms hydrogen sulfide (H25).
• It is primarily important in differentiating…

A

Salmonella (+) from Citrobacter (-).

24
Q

LIA

• Components of LIA:
• pH indicator:

A

lysine, peptones, glucose, ferric ammonium citrate and sodium thiosulfate

bromcresal purple

25
Q

LIA

If the organism produces lysine decarboxylase, ______(purple) is formed.

A

cadaverine

26
Q

LIA

• If the decarboxylase is not produced, the butt______ - K/A.

A

remains acidic (yellow)

27
Q

LIA

If oxidative deamination of lysine occurs, it will form ______color on the slant in the presence of (2)

A

burgundy (red)

ferric ammonium citrate and flavin mononucleotide

28
Q

LIA

• If deamination does not occur, the LIA slant remains_____.

A

purple

29
Q

LIA

• When glucose is fermented, the butt of the medium becomes

A

acidic (yellow).

30
Q

ONGP

is the only ONPG-positive Salmonella serotype.

A

Salmonella arizonae

31
Q

acts on the ONPG (a colorless compound), cleaves it into galactose and orthonitrophenol, and the compound turns yellow.

A

B-galactosidase

32
Q

ONGP

• If the organism is a NLF, the compound…
• (+) result:…

A

remains colorless.

yellow color| within 20 minutes

33
Q

MRVP

• culture medium for MR test:
• VP reagents:
• _____ color - MR test (Escherichia coli) at pH 4.4 or less

A

MRVP broth/Peptone Glucose broth

40% KO and a-naphthol

(+) bright red

34
Q

= VP (+)

A

Kleb-Entero-Serratia-Hafnia group

35
Q

= MR (+) and VP(-)

A

E. coli

36
Q

• This test is helpful in the initial differentiation of Proteus, Morganella and Providencia (only PAD +) from the rest of Enterobaceriaceae.

A

Phenylalanine Deaminase

37
Q

PAD

• Is used to determine the ability of an organism to oxidatively deaminate phenylalanine to phenyl pyruvic acid.
• The phenyl pyruvic acid is detected by adding a few drops of____

A

10% ferric chloride

38
Q

PAD
• (+) result:

A

green colored complex on slant

39
Q
  • rapid urease producers
A

Proteus and Morganella

40
Q

UREASE

• If the slant turns red only -

A

K. pneumoniae.

41
Q

UREASE

• reagent:
• (+) result:

A

urea disk dissolve in 1mL distilled water

change in the color of slant from orange to magenta

42
Q

IMViC Reaction (Indole, Methyl red, Voges-Proskauer and Citrate)

• E. coli, E. tarda, M. morganii
• K. pneumoniae, Enterobacter, Serratia
• Salmonella

A

++ - -
- - ++
-+-+