Laboratory Diagnosis Flashcards

1
Q

What are the 4 common classification schemes for streptococcus?

A
  • hemolytic patter in SBA
  • physiologic characteristics
  • serologic grouping/typing pf C carbohydrate (lancefield classification)
  • biochemical characteristics
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2
Q

Four groups of physiologic characteristics of strep.

A
  • Pyogenic streptococci
  • Lactococci
  • Enterococci
  • vridans streptococci
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3
Q

How to extract the C carbohydrates from streptococci?

A

By placing the organisms in dilute acid and heat for 10 mins.

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4
Q

It has been used as an inexpensive test for presumptive identification of S. pyogenes.

A

Bacitracin Susceptibility

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5
Q

What strep is (S) and (R) to bacitracin?

A

(S)- S. pyogenes
(R)- S. agalactiae

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6
Q

This biochem. Test is used for identification of S. galactiae.

A

CAMP Test

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7
Q

3 ways to perform CAMP Test.

A
  • use of B-lysin producing strain of S. aureus
  • used of disk impregnated with the B-lysin.
  • rapid CAMP test (placing a drop of B- lysin on area of confluent growth of bacteria.
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8
Q

This biochem test is useful test for differentiating S. agalactiae from other B-hemolytic strep.

A

Hippurate Hydrolysis

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9
Q

This enzyme of S. agalactiae hydrolyze sodium hippurate.

A

Hippuricase

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10
Q

In hippurate test, when sodium hippurate is hydrolyzed by the enzyme of S. agalactiae into ___.

A
  • Sodium benzoate
  • Glycine
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11
Q

This test provides a highly probability for the presumptive identification of B- hemolytic GAS and Nonhemolytic group D.

A

Pyrrolidonyl-a-naphthylamide Hydrolysis test

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12
Q

It is the only streptococcus that is positve in PYR test.

A

Strep. pyogenes

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13
Q

What is being detected in PYR test?

A

The activity of L- Pyrrolidonyl arylamidase (pyrrolidonyl aminopeptidase)

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14
Q

What organisms are positive in PYR?

A
  • S. pyogenes
  • Enterococcus
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15
Q

It is a peptidase that hydrolyzes peptide bonds adjacent to a free amino group.

A

Leucin Aminopeptidase

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16
Q

The substrate leucine-B-naphthylamide is hydrolyzed to___.

A

B-naphthylamine

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17
Q

What reagent is added in LAP test to ptoduce red color that signifies (+) results?

A

Paradimethylaminocinnamaldehyde reagent (PDMACA)

18
Q

What organisms are LAP (+)?

A

Streptococcus, Enterococcus, Pediococcus.

19
Q

What organisms are (-) in LAP test?

A

Aerococcus
Leuconostoc

20
Q

This test is used to differentiate the small colony from large colony containing the Group C and G antigen.

A

Voge-proskauer test

21
Q

What is being detecred in VP test?

A

ACETOIN production from glucose

22
Q

In VP test, what is the temp of incubation and time requirement.

A

35°C for 6 hours

23
Q

In VP test, after the incubation period, what should be added?

A
  • 5% a-napthol
  • 40% KOH
24
Q

Positive color in VP test.

A

Red or Pink

25
Q

What is positive and negative in VP test?

A

(+) small colonies- S. anginosus
(-) large colonies

26
Q

This test detects the rxn. Of B-D-glucoronidase

A

B-D-Glucoronidase test

27
Q

What is positive and negative in B-D-Glucoronidase test?

A

(+) large colonies
(-) small colonies

28
Q

Test for identification schemes for nonhemolytic, catalase-negative, gram (+) cocci

A

Bile esculin and salt tolerance test

29
Q

Two steps in bile esculin test.

A
  1. detect the growth of bacteria in 40% bile
  2. The ability to hydrolyze esculin
30
Q

What are positive in bile esculin test?

A

D. streptococci and Enterococci

31
Q

In salt tolerance test what is the concentration of the salt?

A

6.5% NaCl

32
Q

Positive and negative in salt tolerance test.

A

(+) Enterococcus
(-) group D strep.

33
Q

It is a test that adds ethylhydrocuprein hydrochloride to the surface of SBA with a-hemolytic strep.

A

Optochin susceptibility test

34
Q

(R) and (S) in optochin test.

A

(R)- S. viridans group
(S)- S. pneumoniae

35
Q

Zone of inhibition requires to be considered as susceptible in optochin test.(measurement)

A

> 14 mm with 6mm disk or
16 mm with 10mm disk

36
Q

This test correlates with optochin susceptibility test.

A

Bile solubility

37
Q

In bile solubility test, __ took the advantage Becuase of the enzyme amidase.

A

S. pneumoniae

38
Q

In bile solubility test, S. pneumoniae in solution of ____ lyses and make the broth clear.

A

Sodium deoxycholate

39
Q

Organisms positie and negative in bile solubility test.

A

(+) S. Pneumoniae (clear)
(-) Viridans group (turbid)

40
Q

This test can be accomplished by the detection of group-specific antigen from isolates colonies.

A

Immunoassays

41
Q

T or F
Immunoassays are a speedy test, and it is also expensive.

A

True