Lab__2a_Media___Culture_-_Collecting_Bacterial_Samples

It is an enriched medium that will grow even

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. It is an enriched medium that will grow even fastidious bacteria. Also contains 5% sheep blood. This media is not selective . It is enriched and differential : Certain bacteria produce enzymes (hemolysins…say hemo-lice-ins ) that act on red cells to produce either: * Beta hemolysis : Enzymes lyse the blood cells completely, producing a clear area around the colony. * Alpha hemolysis : Incomplete hemolysis produces a greenish discoloration around the colony. * Gamma hemolysis : No effect on the red cells. Blood agar is usually inoculated from a patient’s throat swab. Microbiologist are trying to detect Group A beta hemolytic Streptococcus pyogenes (a Gram-positive cocci-shaped bacteria that causes Beta hemolysis on blood agar.) Normal flora of the throat will exhibit alpha or gamma hemolysis. Images: Beta-hemolysis, Alpha-hemolysis and a sterile plate of Blood Agar , T. Port From the Virtual Microbiology Classroom on ScienceProfOnline.com Watch VIDEO : How to Interpret Blood Agar (BAP)
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Watch VIDEO : How to Aseptically Pour Bacterial Growth Media TSY
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Labeling Plates All Petri plates for this and future lab exercises should be labeled and stored in the following manner: 1. Make certain that all plates are labeled on the bottom half (i.e. the portion of the Petri plate that contains the media). 2. You can label plastic with a sharpie ; glass with a wax pencil . 3. Include the following: a. Your initials or identifying mark b. Date c. Type of specimen 4. All plates are incubated in the green storage bin (which is identified as "SAVE") in the "upside down" position . “Upside down” means that the ½ of the Petri plate with media faces up. The empty ½ of the Petri plate is down. We do not use rubber bands to hold lids in place. (Except for the plates that you may transport home) Plates will be incubated at 37° C for 24 hrs, then stored at room temperature until next week, when you will observe for results. Images: Positive & negative differential reaction on Mannitol Salt Agar , T. Port From the Virtual Microbiology Classroom on ScienceProfOnline.com
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Discard Bin at Back of Lab From the Virtual Microbiology Classroom on ScienceProfOnline.com
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Homework: Environmental Sample After agar in plate has cooled and set: Label one TSY and one MAC using a wax pen. Here’s how… Divide the bottom of each plate (the part of the plate that contains the media) into 4 pie shaped sections and label 1 through 4.
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It is an enriched medium that will grow even fastidious...

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