2. Bacterial staining Flashcards
To study their properties and to divide microorganisms into specific groups for
diagnostic purposes, biological stains and staining procedures in conjunction with
light microscopy have become major tools in microbiology.
Bacterial staining
What are the 2 different types of bacterial stain?
Acidic and Basic stain
What is acidic stain?
- anionic
- Chromogen portion exhibits NEGATIVE charge
- strong affinity to positive constituents of the cell
What is the positive constituent that is being determine by acidic stain?
Proteins
What is basic stains?
- Cationic
- Chromogen portion that exhibits positive charge
- Strong affinity to negative constituent
What is the Negative constituent that is being determine by Basic stain?
Nucleic acid
What are the examples of Acidic stains
Picric acid
Eosin
Acid fuchsin
Rose bengal
Congo red
What are the examples of Basic stains
Methylene blue
Giemsa’s stain
Leishman’ stain
Wright’s stain
What is fixation
Aims to preserve the shape of the cell
When is heat fix incorporate in the slide?
After air drying
A type of stain that is immerse in the sample in a dye solution followed by rinsing and observation
Imparts SAME color from the reagent
Uses only one reagent
Simple stain
Example of simple stain?
Methylene blue
basic fuchsin
Uses 2 or more stains to categorized various groups of bacteria
Differential stain
Example of differential stain
Gram stain
A principal stain that s used for microscopic examination of bacteria
Provides rapid presumption identification of pathogens
Gram stain
Example of bacteria that does not use gram stains
Treponema spp
Mycobacterium spp
Chlamydia spp
What are the 4 reagents in gram staining
P - Crystal violet
M - Gram’s iodine
D - 95% ethyl alcohol/acetone
S - Safranin
What are the time frame in gram staining?
P - 1min
M - 1min
D - 10 sec (Until alcohol runs almost clear that shows blue tinge)
S - 45 sec
Bacteria that will stain and take the primary stain are gram-positive and appear
purple under the compound microscope
Gram positive
Bacteria that will stain and take the counterstain stain are gram-negative and
appear pink under the compound microscope
Gram negative
What is the characteristic of the cell in Gram positive?
Thick
What is the characteristic of the cell in Gram Negative?
Thin
What are the 2 chemical subunits in peptidoglycan?
N-acetylglucosamine
N-acetylmuramic acid
What is the most critical step in gram stain?
Decolorizer
What is being applied in between steps in gram stain
water
It can be used to fix bloody specimens instead of heat fixing
Methanol
What objective lens is used to observe bacterial gram stain
Oil immersion objectives
What are 3 methods in acid fast stains?
Ziehl-Neelsen
Kinyoun method
Auramine Rhodamine
What is the major component of acid fast bacteria?
mycolic acid
A method that use a applicator stick for sputum sample
Coiling method
What are the reagents for acid fast bacilli
P - Carbol fuchsin
D - Acid alcohol (HCL)
S - methylene blue
What is the reagent in heatless method of acid fast stain?
Tergitol for 5 - 10 mins
How many minutes for carbol fuchsin in heat?
5 mins
How many minutes for counterstain in acid fast fast stain
2 mins
What are the symptoms of AFB in the last 2 weeks
Cough
Unexplained fever
Unexplained weight loss
Night sweats
IUATLD/WHO scale of AFB
0
+n
1+
2+
3+
what is seen in +n
BFM: n AFB
200x
- 1-4 AFB in one length
400x
- 1-2 AFB/ length
What is seen in 1+?
BFM: 10-99 AFB/length
200x: 3-24 AFB/length
400x: 1-6 AFB/length
What is seen in 2+?
BFM: 1-10 AFB/50 fields
200x: 25-250/fields AFB/length
400x: 7-60 AFB/field
What is seen in 3+?
BFM: >10 AFB/20 OIF
200x: >250/fields AFB/length
400x: >60 AFB/field
A type of microscope that has increase sensitivity and can be five times faster in detecting AFB
Fluorescence microscope
How many specimen should be submitted in AFB?
2
What is the positive for AFB?
atleast 1 sputum smear
What is the Negative for AFB?
2 sputum smear
What is the specimen for children?
Nasopharyngeal aspirate
gastric lavage
aspirate
What are the examples of capsular stain?
Hiss
Tyeler
Muir
Welch
Novelli
(Hello TYLER, MUkang WELkins NO?)
What bacteria has metachromatic granules?
C. diphtheriae
Example of metachromatic granule stains?
Albert
Neisser
Lamb
Linderhen
Ljubinsky
(And NEISSER La Li Ljubinsky)
are storage granules form for inorganic phosphate and
energy which have the property of metachromasia,
Metachromatic granules
What are the examples of flagella stains?
Leifson
Gray
Silver technique
Caesars gil
Fischer and conn
(Leifson gay because he uses silver technique on Caesar gil that smells Fish and cum)
Allows bacteria to produce a dormant and highly resistant cell to preserve the
cell’s genetic material in extreme stress or starvation
Endspore
What are the examples of endospore stain
Fulton and schaeffer stain
Dolner
Wirtz conklin
Examples of Negative stain
India ink
Nigrossin stain
What bacteria can be detected in india ink?
Cryptococcus neoformans
