Biochem Rodriguez

Question 1

Laboratory Diapnosia (Entorobacterincerel:
Specimen:

Answer 1

stool, rectal swab, blood, urine

Question 2

Colony morphology:- BAP and CAP

Answer 2

large, gray, smooth colonies

Question 3

Transport media

Answer 3

Amies
Cary Blair
Stuart media

Question 4

•Optimal temp

Answer 4

35-37

Question 5

Optimal temp for

yersinia
E. coli

Answer 5

1-5
45-50

Question 6

Fecal pathogens are generally

Answer 6

NLFs

Question 7

Lactose Fermenters:

Answer 7

1. Enterobacter spp.
2. Escherichia coli
3. Klebsiella spp.

Question 8

Late Lactose Fermenters:

Answer 8

1. Citrobacter spp.
2. S. sonnei
3. Hafnia spp

Question 9

Non-Lactose Fermenters:

Answer 9

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

Question 10

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

Answer 10

Mac Conkey -Sorbitol agar

Question 11

• 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.

Answer 11

XLD and HE agars

Question 12

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

Answer 12

HEA

NLF green

XLD

Question 13

• It is the confirmatory test for Salmonella and Shigella

Answer 13

Serotyping (Slide Agglutination Test)

Question 14

Serotyping

• Preferred media for testing:

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

Answer 14

5% sheep’s BAP

sugar

Question 15

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

Answer 15

S. dysenteriae

S. flexneri

S. boydii

S. sonnei (only one serotype)

Question 16

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

Answer 16

B-galactoside permease

Question 17

hydrolyze lactose into glucose and galactose.

Answer 17

B-galactosidase

Question 18

• 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.

Answer 18

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

Question 19

TSI

• pH indicator: pH indicator
H2Sindicators:

Answer 19

phenol red

ferrous sulfate and sodium thiosulfate

Question 20

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.

Answer 20

black color formation

pink to wine colored ring

spread out/movement away from the stab line

Question 21

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:

Answer 21

from gree to blue colored slant

bromthymol blue

Question 22

• Klebsiella and Enterobacter =
• Escherichia and Edwardsiella =

Answer 22

citrate (+)

citrate (-)

Question 23

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…

Answer 23

Salmonella (+) from Citrobacter (-).

Question 24

LIA

• Components of LIA:
• pH indicator:

Answer 24

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

bromcresal purple

Question 25

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

Answer 25

cadaverine

Question 26

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

Answer 26

remains acidic (yellow)

Question 27

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

Answer 27

burgundy (red) ferric ammonium citrate and flavin mononucleotide

Question 28

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

Answer 28

purple

Question 29

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

Answer 29

acidic (yellow).

Question 30

ONGP is the only ONPG-positive Salmonella serotype.

Answer 30

Salmonella arizonae

Question 31

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

Answer 31

B-galactosidase

Question 32

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

Answer 32

remains colorless. yellow color| within 20 minutes

Question 33

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

Answer 33

MRVP broth/Peptone Glucose broth 40% KO and a-naphthol (+) bright red

Question 34

= VP (+)

Answer 34

Kleb-Entero-Serratia-Hafnia group

Question 35

= MR (+) and VP(-)

Answer 35

E. coli

Question 36

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

Answer 36

Phenylalanine Deaminase

Question 37

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____

Answer 37

10% ferric chloride

Question 38

PAD • (+) result:

Answer 38

green colored complex on slant

Question 39

- rapid urease producers

Answer 39

Proteus and Morganella

Question 40

UREASE • If the slant turns red only -

Answer 40

K. pneumoniae.

Question 41

UREASE • reagent: • (+) result:

Answer 41

urea disk dissolve in 1mL distilled water change in the color of slant from orange to magenta

Question 42

IMViC Reaction (Indole, Methyl red, Voges-Proskauer and Citrate) • E. coli, E. tarda, M. morganii • K. pneumoniae, Enterobacter, Serratia • Salmonella

Answer 42

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