Testing Antibacterial Properties with the Kirby-Bauer Method

The video demonstrates the Kirby-Bauer method for testing antibacterial properties. It begins with labeling and inoculating a plate with bacteria using aseptic techniques. Filter paper discs are prepared with chemicals and placed on the plate. After 24 hours of incubation, the results show zones of inhibition indicating antibacterial properties of the chemicals tested.

What is the primary purpose of the Kirby-Bauer method?

• To measure the growth rate of bacteria

• To test a substance for its antibacterial properties

• To identify different types of bacteria

• To create a sterile environment

How is the plate divided for testing different substances?

• Into six sections labeled A, B, and C

• Into four sections labeled 1, 2, 3, and 4

• Into two sections labeled Left and Right

• Into three sections labeled X, Y, and Z

What is the first step in inoculating the plate with bacteria?

• Placing the plate in the incubator

• Dipping the swab in ethanol

• Flaming the top of the tube

• Labeling the plate

Why is it important to cover the entire surface of the plate with bacteria?

• To save time during the experiment

• To make the plate look uniform

• To prevent contamination

• To ensure even bacterial growth

What is used to sterilize the forceps before handling the filter paper discs?

• Bleach solution

• 95% ethanol

• Boiling water

• Hydrogen peroxide

What precaution should be taken when using ethanol near an open flame?

• Wear protective gloves

• Be careful to avoid ignition

• Use a larger amount of ethanol

• Ensure the flame is extinguished

How long should the plate be incubated, and at what temperature?

• 12 hours at 25 degrees Celsius

• 24 hours at 37 degrees Celsius

• 48 hours at 30 degrees Celsius

• 24 hours at 25 degrees Celsius

What indicates that Chemical C has antibacterial properties?

• No change in the plate

• Increased bacterial growth

• A zone of inhibition around the disc

• A change in color of the agar

What observation suggests that Chemical B lacks antibacterial properties?

• A large zone of inhibition

• Bacteria growing up to the edge of the disc

• A change in the color of the disc

• A reduction in bacterial growth

What does a small zone of inhibition around Chemical A indicate?

• Slight antibacterial properties

• No antibacterial properties

• Complete bacterial resistance

• Strong antibacterial properties