In What Kind Of Clinical Situation Would A Direct Smear Report From The Lab Be Of Urgent Importance

1. Following the procedures outlined in Exercise 4, steps 1 through 6 (pages 34—35), prepare a fixed smear of each culture and of the simulated clinical specimen. You will have 7 smears labeled Se, Ef, Ns, Sc, Bs, Ec, Pv, and pus. On the underside of each slide, make a code mark so that you can identify the slides after staining.

2. Stain each smear by the following procedures (this is Hucker's modification of the Gram stain):

a. Flood slide with crystal violet. Allow to stand for one minute (check with instructor; time varies with different batches of stain).

b. Wash off with tap water.

c. Flood with Gram's iodine (a mordant). Leave for one minute.

d. Wash off with tap water.

e. Decolorize with alcohol (95%) until no more color washes off (usually 10—20 seconds). This is a most critical step. Be careful not to overdecolorize, as many gram-positive organisms may lose the violet stain easily and thus appear to be gram negative after they are counterstained.

f. Wash off with tap water.

g. Apply safranin (the counterstain) for one minute.

h. Wash off with tap water.

i. Drain and blot gently with bibulous paper. Air dry the slide thoroughly before you examine the preparation under the microscope.

3. When slides are dry, label them as shown:

Name

Date

/ Stained 1

Organism

( smear j

(or specimen)

Morello-Mizer-Granato: I I. Basic Techniques of I 3. Differential Stains I I © The McGraw-Hill

Laboratory Manual and Microbiology Companies, 2003 Workbook in Microbiology, 7/e

4. Examine all slides under oil with the oil-immersion objective.

5. Record observations in table under Results.

6. Examine colorplates 1—6 and 8, noting which bacteria are gram positive or gram negative.

Results

Diagram

Name of Organism

Agar cultures

Color (Purple or Pink)

Pus specimen: Describe type(s) of organisms seen

Morello-Mizer-Granato: I I. Basic Techniques of I 3. Differential Stains I I © The McGraw-Hill

Laboratory Manual and Microbiology Companies, 2003 Workbook in Microbiology, 7/e

Questions

1. What is the function of the iodine solution in the Gram stain? If it were omitted, how would staining results be affected?

2. What is the purpose of the alcohol solution in the Gram stain?

3. What counterstain is used? Why is it necessary? Could colors other than red be used?

4. On the basis of Gram reaction, can you distinguish species of:

Staphylococcus and Streptococcus? _

Staphylococcus and Neisseria? _

Escherichia and Proteus? _

Escherichia and Bacillus? _

5. What is the size of staphylococci in micrometers? In centimeters?

Morello-Mizer-Granato: I. Basic Techniques of 3. Differential Stains © The McGraw-Hill

Laboratory Manual and Microbiology Companies, 2003

Workbook in Microbiology, 7/e

6. What is the advantage of the Gram stain over the simple stain?

7. In what kind of clinical situation would a direct smear report from the laboratory be of urgent importance?

8. What is the current theory about the mechanism of the Gram-stain reaction?

9. Describe at least two conditions in which an organism might stain gram variable.

Morello-Mizer-Granato: I I. Basic Techniques of Laboratory Manual and Microbiology

Workbook in Microbiology, 7/e

3. Differential Stains

Name

Class

Date

Exercise

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Responses

  • alexa
    When would a direct smear from the laboratory be of urgent importance?
    8 years ago
  • dionisia fanucci
    What kind of clinical situation would direct smear report be urgent?
    8 years ago
  • bellisima
    What chemical situation would a direct smear report from the lab be of urgent importance?
    8 years ago
  • olo brown
    What is the current theory about the mechanism of the gramstain reaction?
    8 years ago
  • Christian
    What clinical situation would a direct smear report be needed?
    8 years ago
  • Jennifer Weissmuller
    What kind of clinical situations would a direct smear report from the lab be of urgent importance?
    8 years ago
  • pekka
    When would a direct smear report be important?
    8 years ago
  • Aatifa
    What counterstain is used Why is it necessary?
    8 years ago
  • lochlan
    What kind of clinical situation would a direct smear report from the lab be of urgent importance?
    8 years ago
  • Olivia
    When would a direct smear report from the lab be of critical importance?
    7 years ago
  • haben
    What counterstain is used Why is it necessary Could colors other than red be used?
    7 years ago
  • dieter
    What is a negative stain in what clinical situation might it be used?
    7 years ago
  • PRIMULA
    What kind of clinical situation would a direct smear report from the laboratory of urgent importance?
    7 years ago
  • maik
    What would make a gram stain urgent?
    6 years ago
  • bell
    When will a diect smear be important or urgent?
    5 years ago
  • robinia
    What is the purpose if iodine in direct smears?
    4 years ago
  • pio
    What would make a direct smear report urgent?
    4 years ago
  • Pia
    What clinical situation would a direct smear report from the laboratory be of urgent important?
    4 years ago
  • Antonia Palermo
    When direct smear is urgent in nicrobiology?
    4 years ago
  • Timothy
    When do a smear preparation be of urgent report be of urgent important in clinical situation?
    3 years ago
  • felix
    Why might a direct smear report from the lab be of urgent importance in a clinical siutation?
    2 years ago
  • JAN
    Why would smear be marked as urgent?
    2 years ago
  • Vilma
    What is the size of staphylococci in centimeters?
    2 years ago
  • ayesha
    When would a direct smear report be urget?
    1 year ago
  • gilly
    When is a gramstain report form the laboratory be urgent?
    7 months ago

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