[2S] UNIT 4 Smear Prep & Staining Tech (Exp 6) Flashcards
Principle: Distinguish if the isolate is Gr (+) or Gr (-)
Gram staining
2 TYPES OF SMEAR
Prepared from colonies growing from plated media
Indirect Smear
GRAM STAINING
Gr (+) bacteria : stained?
Purple
GRAM STAINING
Gr (-) bacteria is stained?
Red
Based on the reaction of bacterial cell wall on staining solutions
Gram Staining
2 TYPES OF SMEAR
Prepared from clinical specimen
Direct Smear
Gram Stain Procedure
Stain:
Mordant:
Decolorizer:
Counterstain:
VIAS
Stain: Crystal Violet, 1 min
Mordant: Gram’s Iodine, 1 min
Decolorizer: Acetone-alcohol / 95% Ethanol, 10 secs
Counterstain: Safranin, 30 secs
DIRECT GRAM SMEAR
Select the ________ or ___________ of the sputum specimen using an applicator stick, pasteur
pipette, or inoculation loop
purulent or blood-tinged portion
What to do when the smear is too thick?
Pull apart method of smear preparation can be performed
Direct gram smear must be a _____ size or ____ to form a thin film of smear
thumb; 2x3 cm
How many times should you pass your direct gram smear through the flame?
4-5 times
Alternative for heat fixing in direct gram smear
Flooding with absolute methanol for 1 minute
T/F: Gram staining smear should have pink/red or clear background and cells are overlapping
F; cells should not be overlapping
Adding 1-2 drops of NSS on the slide
Indirect Gram Smear
Shape of the smear
oval
INDIRECT GRAM SMEAR (+NSS)
Fish out ___ similar looking colonies emulsify with NSS
1-2
INDIRECT GRAM SMEAR
Air dry → Pass through the flame ____
3 - 4 x
GRAM STAINING
Examine in ______ / ______ scanning
Horizontal / Vertical
MICROSCOPIC EXAMINATION : DIRECT STAINING
Microscopic structures present
HERP
Host cellular material
Epithelial cells
RBCs
PMNs
MICROSCOPIC EXAMINATION : DIRECT STAINING
Enumeration of Cells Under LPO = 1+
1+ = </LPF
MICROSCOPIC EXAMINATION : DIRECT STAINING
Enumeration of Cells Under LPO = 4+
4+ = >25/LPF
MICROSCOPIC EXAMINATION : DIRECT STAINING
Enumeration of Cells Under LPO = 2+
2+ = 1-9/LPF
MICROSCOPIC EXAMINATION : DIRECT STAINING
Enumeration of Cells Under LPO = 3+
3+ = 10-25/LPF
MICROSCOPIC EXAMINATION : DIRECT STAINING
Enumeration of Bacteria Under OIO = 1+
1+ (rare or occasional) = <1/OIF
MICROSCOPIC EXAMINATION : DIRECT STAINING
Enumeration of Bacteria Under OIO = 2+
2+ (few) = 1-5/OIF
MICROSCOPIC EXAMINATION : DIRECT STAINING
Enumeration of Bacteria Under OIO = 3+
3+ (moderate) = 6-30/OIF
Principle: For the detection of Tubercle bacilli in sputum specimen
Acid Fast Staining
MICROSCOPIC EXAMINATION : DIRECT STAINING
Enumeration of Bacteria Under OIO = 4+
4+ (heavy) = >30/OIF
AFS
Causative agent of Mycobacterium Tuberculosis (PTB & EPTB)
Tubercle bacilli
Resist decolorization w/ acid-alcohol and appear
red on a blue / green background after decolorization
Acid Fast Staining: Tubercle bacilli
AFS
Alternative for Direct Sputum Smear Microscopy
GeneXpert (Nucleic Acid Amplification Test)
AFS
Primary diagnostic and monitoring tool for TB
Direct Sputum Smear Microscopy
AFS specimen collection and time
Collected preferably early
morning
AFS
A sputum should be?
A sputum should be thick, cloudy, and sticky
AFS SMEAR PREPARATION
Using the flattened end of an applicator stick or a flamesterilized loop, pick the _______ portion of sputum sample and place it on the slide
purulent
AFS SMEAR PREPARATION
Spread until it forms an oval-shaped smear with _____ dimension
2x3 cm