国外微生物学基础实验(三)-英文版
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• TURN IN: No lab report or Pre-lab due this week.
End of Today’s Lab
• After you have cleaned your lab bench, copy your Lab #2 and #3 material on to a clean copy to take home. I must see you throw out your dirty copy of Lab #2.
Gamma hemolysis: No effect on the red cells.
Blood agar is usually inoculated from a patient’s throat swab.
Getting Ready for Today’s Lab
• Grab your lab check-in card and the dirty copies of Lab #2 and #3 that we saved from last week.
• Grab your plastic box of supplies.
Βιβλιοθήκη Baidu
Blood agar
Most specimens received in a clinical microbiology lab plated onto Blood Agar, since it supports the growth of most organisms. Blood agar contains
5% sheep blood.
This media is differential because:
Certain bacteria produce enzymes (hemolysins…hemo-lice-ins) that act on the red cells to produce either:
• Put on your lab coat and have your goggles, lab card and dirty copies of lab exercises/reports on the bench next to you.
• Plug in and turn on your microincinerator.
1. What Does Selective Mean? MacConkey’s is selective media because it inhibits the growth of some organisms [Gram positive bacteria].
2. What Does Differential Mean? Because “neutral red” has been added to the media, it is also differential.
• You may turn in your dirty copy of Lab #3 to save for use next week.
• Lab Report #2 and #3 due next week, as week, as well as Pre-lab #4.
Laboratory 3
Members of the family Enterobacteriaceae (Gram negative bacilli) are the most frequently encountered bacteria isolated from many types of clinical specimens. They are most commonly lactose fermenters.
Differential Staining
G
s
u
e
Three Main Things We are Doing Today
I. Looking at Results from Last Weeks Cultures
II. Learning to use an Inoculation Loop for Streak Plate Method
Blood Agar = very dark red McConkeys = lighter, purplish-pink Mannitol Salt -= orangish-pink
MacConkey's (already prepared)
MacConkey’s is both a selective & differential media.
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.
III. Differential Stains
I. Looking at Results from Last Weeks Cultures
Other Types of Media: McConkey’s, Blood Agar & Mannitol Salt
Look at the plates on your lab bench that are red/pink In color.
- Bacteria that use lactose (a type of sugar) for food, produce acidic metabolites which causes the pH indicator neutral red to turn red.
- These “lactose fermenters” will grow in red colonies while non-lactose fermenters will be colorless and clear.
End of Today’s Lab
• After you have cleaned your lab bench, copy your Lab #2 and #3 material on to a clean copy to take home. I must see you throw out your dirty copy of Lab #2.
Gamma hemolysis: No effect on the red cells.
Blood agar is usually inoculated from a patient’s throat swab.
Getting Ready for Today’s Lab
• Grab your lab check-in card and the dirty copies of Lab #2 and #3 that we saved from last week.
• Grab your plastic box of supplies.
Βιβλιοθήκη Baidu
Blood agar
Most specimens received in a clinical microbiology lab plated onto Blood Agar, since it supports the growth of most organisms. Blood agar contains
5% sheep blood.
This media is differential because:
Certain bacteria produce enzymes (hemolysins…hemo-lice-ins) that act on the red cells to produce either:
• Put on your lab coat and have your goggles, lab card and dirty copies of lab exercises/reports on the bench next to you.
• Plug in and turn on your microincinerator.
1. What Does Selective Mean? MacConkey’s is selective media because it inhibits the growth of some organisms [Gram positive bacteria].
2. What Does Differential Mean? Because “neutral red” has been added to the media, it is also differential.
• You may turn in your dirty copy of Lab #3 to save for use next week.
• Lab Report #2 and #3 due next week, as week, as well as Pre-lab #4.
Laboratory 3
Members of the family Enterobacteriaceae (Gram negative bacilli) are the most frequently encountered bacteria isolated from many types of clinical specimens. They are most commonly lactose fermenters.
Differential Staining
G
s
u
e
Three Main Things We are Doing Today
I. Looking at Results from Last Weeks Cultures
II. Learning to use an Inoculation Loop for Streak Plate Method
Blood Agar = very dark red McConkeys = lighter, purplish-pink Mannitol Salt -= orangish-pink
MacConkey's (already prepared)
MacConkey’s is both a selective & differential media.
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.
III. Differential Stains
I. Looking at Results from Last Weeks Cultures
Other Types of Media: McConkey’s, Blood Agar & Mannitol Salt
Look at the plates on your lab bench that are red/pink In color.
- Bacteria that use lactose (a type of sugar) for food, produce acidic metabolites which causes the pH indicator neutral red to turn red.
- These “lactose fermenters” will grow in red colonies while non-lactose fermenters will be colorless and clear.