Kirby-Bauer Disk Diffusion Method

The video tutorial explains the Kirby-Bauer disk diffusion method, a technique used to determine the susceptibility of organisms to antimicrobials. It covers the principles of the method, including the creation of inhibitory zones and the importance of standardization and quality control. The process involves preparing a bacterial suspension, inoculating an agar plate, placing antimicrobial disks, and incubating the plate. The results are measured and interpreted using CLSI guidelines, which provide criteria for determining susceptibility or resistance.

What is the main purpose of the Kirby-Bauer disk diffusion method?

• To identify bacterial species

• To determine the susceptibility of an organism to antimicrobials

• To measure the growth rate of bacteria

• To test the effectiveness of disinfectants

Which factor is NOT important to standardize in the disk diffusion test?

• Media composition

• Incubation temperature

• Color of the agar

• Inoculum density

What is the first step in preparing for a Kirby-Bauer disk diffusion test?

• Inoculating the agar plate

• Making a bacterial suspension

• Measuring zone diameters

• Placing antimicrobial disks

Why is it important to vortex the bacterial suspension?

• To cool down the suspension

• To ensure a homogeneous suspension

• To sterilize the suspension

• To increase bacterial growth

What should be done before placing antimicrobial disks on the agar plate?

• Warm them to room temperature

• Freeze them for stability

• Soak them in water

• Expose them to sunlight

Why is the placement of antimicrobial disks important?

• To increase the number of disks on the plate

• To ensure they are evenly spaced

• To prevent overlapping of inhibitory zones

• To make the plate look organized

At what temperature should the agar plate be incubated?

• 40 degrees Celsius

• 25 degrees Celsius

• 30 degrees Celsius

• 35 degrees Celsius

How are the inhibitory zones measured?

• In centimeters

• In millimeters

• In meters

• In inches

What is the purpose of the CLSI guidelines?

• To list all known bacteria

• To describe the history of microbiology

• To provide recipes for agar media

• To offer interpretive criteria for susceptibility tests

What zone diameter is considered susceptible for cephalosporin in Staphylococcus suite intermedius?

• Exactly 22 millimeters

• 21 to 23 millimeters

• Less than 20 millimeters

• Greater than or equal to 24 millimeters