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BACTE LAB REMOVALS > Biochemical Tests > Flashcards

Biochemical Tests Flashcards

1
Q

is used to identify bacterial species based
on the differences in the biochemical reactions of each of
the different types of bacteria

A

Biochemical test

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2
Q

The is used to identify bacteria that
produce cytochrome c oxidase, an enzyme of the
bacterial electron transport chain (ETC)

A

oxidase test

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3
Q

t is based on the principle that
certain bacteria produce indophenol blue from the
oxidation of dimethyl-p-phenylenediamine and anaphtho

A

Principle of Oxidase tes

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4
Q

 Oxidase POSITIVE bacteria:

A

o Pseudomonas
o Vibro cholerae
o Neisseriae
o Campylobacter
o Helicobacter / Haemophilus
o Aeromonas
o Alcaligene

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5
Q

Precaution while performing oxidase test:

A

o Do not use nickel-base alloy wires containing
chromium and iron wire (nichrome wire).
o Interpret test within 10 seconds.
o Perform test using 5% SBA or on a medium without fermentable sugar

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6
Q

maintains osmotic pressure. in tsi

A

Nacl

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7
Q

are the fermentable
carbohydrates

A

Lactose, Sucrose, and Dextrose

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8
Q

S make H2S (Hydrogen sulfide) indicator system

A

sodium thiosulfate and ferrous sulfate

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9
Q

is reduced to H2S by several species of bacteria
and H2S combines and form insoluble black precipitates.
FeSO4 present in the medium

A

Thiosulfate

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10
Q

how long is the incubation for tsi

A

Incubation is for 18 to 24 hours in order to detect the
presence of sugar fermentation, gas production, and H2S
production

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11
Q

It is also used to distinguish the Enterobacteriaceae from other gram-negative intestinal bacilli (by their ability to catabolize glucose, lactose, or sucrose, and to liberate sulfides from ferrous ammonium sulfate or sodium thiosulfate

A

TSI

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12
Q

agar slants contain a 1% concentration of
sucrose and lactose, and 0.1% glucose

A

TSI

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13
Q

IN TSI, it is incorporated into
the medium to detect acid production from
carbohydrate fermentation.

A

phenol red

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14
Q

tsi results color

A

The indicator is pink at alkaline pH and yellow in acidic pH, at neutral pH it remains red

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15
Q

Yellow butt (A) and red slant (K)

A
  • due to fermentation of glucose (phenol indicator turns yellow due to persisting acid formation in the butt)
  • The slant remains red (alkaline) (K) because of
    limited glucose in the medium. Therefore, limited acid formation, which does not persist.
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16
Q

A yellow butt (A) and slant (A)

A

due to fermentation of lactose and/or sucrose.

  • Yellow slant and butt due to high concentration of these sugars leading to excessive acid formation in the entire medium.
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17
Q

o noted by splitting agar.

A

Gas formation

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18
Q

o seen by blackening of agar.

A

Gas formation (H2S)

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19
Q

red butt (K) and slant (K)

A

introduces that none of the sugars were fermented and neither gas nor H2S produced.

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20
Q

Slant Butt Gas H2S

of Escherihia,

A

Acid (A) Acid (A) Pos (+) Neg (-)

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21
Q

Klebsiella,

Slant Butt Gas H2S

A

Acid (A) Acid (A) Pos (+) Neg (-)

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22
Q

Enterobacte

Slant Butt Gas H2S

A

Acid (A) Acid (A) Pos (+) Neg (-)

23
Q

Slant Butt Gas H2S

shigella

A

Shigella,

Alkaline (K) Acid (A) Neg (-) Neg (-)

24
Q

Slant Butt Gas H2S

Serratia

A

Serratia
Alkaline (K) Acid (A) Neg (-) Neg (-)

25
Q

Slant Butt Gas H2S

salmonella

A

Salmonella,

Alkaline (K) Acid (A) Pos (+) Pos (+)

26
Q

Slant Butt Gas H2S

proteus

A

Proteus
Alkaline (K) Acid (A) Pos (+) Pos (+)

27
Q

Slant Butt Gas H2S

Pseudomonas

A

Pseudomonas
Alkaline (K) Alkaline (K) Neg (-) Neg (-)

28
Q

If an Enterobacteriaceae contains amino acid
decarboxylase, amines produces by decarboxylae action
cause an ________ pH, and _________

A

Amino acid decarboxylation

alkaline ph

bromocresol purple

29
Q

Amino acid decarboxylation

result

A

alkaline = purple = positive/amino acid is decarboxylated

acidic = yellow/glucose fermentation acidifie s broth

30
Q

Decarboxylation patterns are essential for the genus
identification of

A

Klebsiella, Enterobacter, Eschericia, and
Salmonella

Enterobacter aerogenes, E. cloacae,
Proteus mirabilis, and Shigella sonnei

31
Q

Aim: To differentiate gram-negative bacilli based on decarboxylation or deamination of the lysine and the formation of hydrogen sulfide (H2S).

A

Lysine Iron Agar

32
Q

Lysine decarboxylation is indicated by an increase in

A

alkaline (purple)
medium

33
Q

 Lysine deamination is detected by a

A

red slant.

34
Q

Dextrose fermentation is indicated by a

A

purple slant and a
yellow butt

lia

35
Q

deaminate lysine which
results in a distinctive red slant over an acid (yellow) butt. give example

A

Proteus and Providencia spp.

36
Q

To determine the ability of microbe to
degrade amino acid tryptophan.

A

Indole Production Test

37
Q

indole production test result

A

: Development of cherry red colour at the
interface of the reagent and the broth, within seconds after adding the Kovacs’ reagent indicates the presence of indole and the test is positive.

If no color change is observed, then the test is negative and so organisms are not
capable of producing tryptophanase

38
Q

To differentiate E. coli and E. aerogene

A

mr

e. coli +

e. aerogenes -

39
Q

determine the ability of microbes to oxidize glucose with
production and stabilization of high content of acid end
product.

A

mr

40
Q

differentiate the E.coli and E. aerogenes by the
production of 2,3-butanediol and
acetoin via glucose fermentation

A

VP

e. coli -

e. aerogenes +

41
Q

RESULT IN VP

A

nterpretation: Development of crimson red color indicates positive test for E. aerogenes; and no color indicates negative test

42
Q

Principle: This test determines the capability of some organisms to produce non-acidic or neutral end products, such as acetyl methyl corbinol (acetoin), from the organic acid that results from glucose metabolism

A

vp

43
Q

Aim: To determine the ability of the microbes to ferment
citrate as sole carbon source

A

Citrate Test

44
Q

cARBON AND NITROGEN SOURCE IN CITRATE TEST

A

Sodium citrate as the carbon source, Ammonium
(NH4
+) as a nitrogen source

45
Q

CITRATE TEST RESULT

A

+ = BLUE
- = NO COLOR

46
Q

UREASE TEST RESULT

A

+ = REDDISH PINK TO RED
- = YELLOW

47
Q

The hydrolysis of urea is catalysed by specific enzyme urease to yield

A

2 moles of ammonia, water, CO2.

48
Q

o determine the ability of
microbes to ferment sugars with the
production of an acid and/or gas

A

Sugar Fermentation Test

49
Q

If fermenting bacteria are grown in a liquid culture
medium containing the carbohydrate, they may
produce ______as by-products of the
fermentation.

A

If fermenting bacteria are grown in a liquid culture
medium containing the carbohydrate, they may
produce organic acids as by-products of the
fermentation.

50
Q

Gases produced during the fermentation process can
detect by using a small, inverted tube (Durham tube)
within the liquid culture medium

A

Sugar Fermentation TesT

51
Q

Sugar Fermentation TesT RESULT

A

Interpretation:
o If the medium changes from colorless to yellow and
gas bubble is found in Durham’s tube then it indicates
acid and gas production.
o If no change observed in the color of medium then
sugar is not degraded by the organism

52
Q

To determine the ability of some microbes to reduce
nitrate (NO3
-
) to nitrites (NO2
-
) or beyond the nitrite stage

A

NITRATE REDUCTION

53
Q

RESULT OF NITRATE REDUCTION

A

+ = RED

54
Q
A

BACTE LAB REMOVALS (6 decks)

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