Bacterial staining Lab 5 AL Noor Ameer Purpose of culturing is 1 Isolation of microorganisms from a sample 2 For counting the microorganism in the sample 3 Obtain pure ID: 760454
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Slide1
Culturing methods& Bacterial staining
Lab. 5
A.L. Noor Ameer
Slide2Purpose of culturing is:
1- Isolation of microorganisms from a
sample.
2-
For counting the microorganism in the
sample.
3-
Obtain pure
cultures.
4-
To test for antibiotic
sensitivity.
Slide3Culture methods include:
1- Streaking plates: Used for the isolation of bacteria in pure culture from clinical specimens (to obtain pure colonies), include:
a- ABCD method: (by using loop
).
b- Continuous streaking (by using loop
).
Slide42- Streaking of the slant: (by using loop).
3- Stab culture (by using needle).
4- Lawn culture: (by using swab
).
5-
Pour
plate
method.
6- Spread plate
method
(glass spreading
rod)
Slide5Bacterial staining
The bacteria are stained for the following
reasons:
1- To study their shapes
2-
To differentiate the species of bacteria by using differential
stain
3-
To study the internal components of the bacterial cell
Slide6Based on the function of stain is divided into:
1- Simple stain: using of a single dye to staining the bacteria as methylene blue, safranin, and crystal violet can be used to determine cell shape, size, and arrangement.
2- Differential stain: using of more than one dye used to differentiate between different
bacteria
3- Selective stain: using of more than one dye to determine the special structure such as spore, capsule, flagella, cell wall & nucleic acid staining.
Slide7Differential stain
1- Gram staining: used to differentiate bacteria into 2 large groups Gram positive which are blue- purple in color and Gram negative bacteria are pink- red in
color
- Include stains
:
1-
Primary stain (crystal violet)
.
2-
A mordant: (iodine solution
).
3-
A decolorizing agents: ( alcohol, acetone
).
4-
Counter stain: (safranin)
Slide82- Acid- fast stain (
Ziehl
-
Neelson
stain): used to determine acid fast organisms that causes tuberculosis (Mycobacterium tuberculosis) which appear as pink bacilli - Include stains:
1-
Primary stain: (
carbol
fuchsin
).
2- A decolorizing agents: ( acid alcohol
).
3-
Counter stain: (methylene blue)
Slide9Selective stain
1-
Endospore stain:
used to distinguish between the vegetative cells and the endospores. A primary stain (malachite green) is used to stain the endospores while the safranin used as counterstain, the vegetative cells will appear pink and the spores will appear green. Ex: Bacillus &
Clostridium.
2-
Capsule staining:
used to observe bacterial capsule of
Klebsiella
pneumonia or any bacteria have a capsule by using primary stain (crystal violet for 2 minutes), the
encapsulsated
cells will have a halo appearance under the
microscop
Slide103- Flagella stain: flagella are fine, threadlike organelles and usually invisible under light microscope to observe it must be bind with chemical substances such as tannic acid & potassium alum. to increasing the thickness of flagella and then staining with basic
fuchsin
or silver nitrate
.