Remove the agar plate from its lid with the left hand. While holding the plate, inoculate the agar heavily near the periphery of the plate down to approximately a quarter size circle. (See diagram step #1.) You may use the same swab for each broth culture on several plates, as long as the swab is used in this order:, BAP,
Based on the found under #4 inoculating plates order, and the definitions above, what can you assume the order of plating cultures is based on?
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Introduction -- Microbes are around and every where in environment.
Sterile agar plates which provide the nutrients and suitable pH for bacteria to grow .
Agar --Agar is a polysaccharide derived from red algae .
Agar powder is first dissolved in a boiling liquid and then cooled to form a gelatinous solid matrix .As microbes can not digest agar so it is used commonly in laboratories to hold the nutrients which are required by bacteria for their survival .
Handling of the Agar plate -- It is very necessary to understand the handling microbiological media to obtain optimum result --
1- Microbiological media must be kept refrigerated or on ice until ready to use .
2 -The plates must be allowed to warm up to room temperature before taking a sample .
3 - Don't remove the lid plate at any time except during sampling .
4 -Adequate packing material must be sent to protect the plates .The weight of icepack can crush the plates during shipping .
5 - Plates must not come in to direct contact with the ice , as the tests will be invalid if the media freezes .
6 - If there is any delay in sending the agar plate the plates should be refrigerated until ready for delivery .
Sampling Tips -- Washing the hands with soap or sanitize before wearing the latex gloves .
Use 70% isopropyl alcohol to sterilize sample.
Place lid to Petri dish in a sterile bag during sampling .
Include an outside sample for a control and a blank .
BAP Agar -- ABAP agar is used as a general blood agar medium .
BAP agar is a different growth medium which microbiologist use to identify clinically significant bacteria from throat and sputum culture .
BAP contains 5% sheep blood i.e. trypticase soy agar ( TSA ) + 5% sheep blood .
Use - It is used for growth and testing of N meningitidis and S. pneumoniae .
MaC Agar --MacConkey Agar is a selective and differential culture medium for bacteria .It is designed to selectively isolate Gram - negative and enteric ( normally found in the intestinal tract ) bacteria and differentiate them based on lactose fermentation .
The contains bile salts as well as crystal violet dye and neutral red dye with in media prevent gram positive organisms from growing .
Use -- Using neutral pH indicator the agar distinguish Gram - negative bacteria which can ferment the sugar lactose ( Lac + )from those can not ( Lac - ).
This is known as indicator medium and a low selective medium .
Presence of bile salts inhibits swarming by Proteus species .
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