4.2.2 Laboratory diaganosis Corynebacterium

Question 1

What is the microscopic characteristics of Corynebacterium spp.

Answer 1

• Pleomorphic Gram positive bacilli
• Irregularly staining in metachromatic areas

Question 2

What is pleomorphic?

Answer 2

Different shapes, forms or arrangement

Question 3

What is the arrangement and shape of bacteria?

Answer 3

Club shape and palisade

Question 4

What are the agar use for Corynebacterium?

Answer 4

• Tinsdale agar
• Cystine-Tellurite blood agar
• Loeffer serum agar/Pai agar

Question 5

What can be seen in Tinsdale agar?

Answer 5

Black colonies with brown halo

Question 6

What is the composition of Tinsdale agar which is responsible for producing black colonies?

Answer 6

L-cystine
Sodium thiosulfate/potassium tellurite

Question 7

What is the function of sodium thiosulfate?

Answer 7

H2S producer

Question 8

What type of agar is CTBA?

Answer 8

Nutrient agar

(Selective)

Question 9

Does CTBA contains blood?

Answer 9

No

Question 10

What is the additional composition of CTBA?

Answer 10

Bovine serum

RBC

Question 11

What is the function of potassium tellurite?

Answer 11

Inhibits non-Corynebacterium or upper respiratory tract normal flora

reduction of potassium tellurite to tellurium (Black colonies)

Question 12

Used to demonstrate pleomorphism and metachromatic granules

Answer 12

Loeffer serum agar/Pai agar

Question 13

What is being added in Pai agar to enhance growth?

Answer 13

Blood and serum

Question 14

Test the ability of a organism to produce the enzyme urease which hydrolyzes urea

Answer 14

Urease hydrolysis (Stuart broth)

Question 15

What is the indicator for Stuart broth?

Answer 15

Phenol red

Question 16

Function of urease?

Answer 16

Breakdown of urea into ammonia and CO2

Question 17

What is the positive indicator for Stuart broth?

Answer 17

orange = weak +
Pink = Strong +

Question 18

What is the negative indicator for Stuart broth?

Answer 18

Yellow

Question 19

What organisms that has orange in Stuart broth?

Answer 19

C. ulcerans,
C. pseudotuberculosis

Question 20

What organisms that has Yellow in Stuart broth?

Answer 20

C. diphtheriae

Question 21

Determines the ability of an organisms to produce proteolytic enzymes that liquefies gelatin

Answer 21

Gelatin hydrolysis

Question 22

What is the positive indicator for gelatin hydrolysis?

Answer 22

Partial or full liquefaction of inoculated tube

Question 23

What is the negative indicator for gelatin hydrolysis?

Answer 23

Complete solidification of the tube

Question 24

What organisms is positive in gelatin hydrolysis

Answer 24

C. ulcerans

Question 25

What bacteriw is negative for gelatin hydrolysis?

Answer 25

C. pseudotuberculosis

Question 26

Identification of DNA

Answer 26

PCR

Question 27

Detection of Antigen-antibody complex

Answer 27

Enzyme-linked immunoassay (ELISA)

Question 28

Test for toxigenicity of C. diphtheriae

Answer 28

Elek test

Question 29

What is the positive indicator for Elek test?

Answer 29

Precipitin line (Line of identity)

Question 30

In elek test, oraganism is streaked usually parallel _______ apart

Answer 30

10mm

Question 31

In Elek test, what is place in the middle

Answer 31

Antitoxin-impregnated filter paper

Question 32

What are the 4 streaks indicates in Elek test?

Answer 32

1. Positive control 2. Unknown toxigenic 3. Negative control 4. Unknown Non toxigenic

Question 33

In elek test, how many hours for checking?

Answer 33

18, 28, 40 (18, 24, 48 - book)

Question 34

What is the temp for incubation in elek test?

Answer 34

35C

Question 35

What is the angle for line of identity?

Answer 35

45 degrees

Question 36

What is the treatment for diphtheria?

Answer 36

Antitoxin