Question

Which method is used to determine the Minimum Inhibitory Concentration (MIC) of an antibiotic?

• A. Disk diffusion method
• B. Broth dilution method
• C. Gram staining
• D. Streak plate method

Hint:

MIC determination → Broth dilution method → Lowest concentration with no growth.

Answer 1

The Correct Option is B

Concept: Minimum Inhibitory Concentration (MIC) is the lowest concentration of an antibiotic that inhibits visible growth of a microorganism. It is an important parameter in antimicrobial susceptibility testing.
Step 1: Understanding MIC.
MIC helps determine the effectiveness of an antibiotic against a specific pathogen and guides appropriate dosage.
Step 2: Method used.
The broth dilution method is commonly used to determine MIC by preparing serial dilutions of an antibiotic in liquid growth medium.
Step 3: Procedure.

• Prepare a series of tubes with decreasing concentrations of antibiotic
• Inoculate each tube with the test microorganism
• Incubate and observe for growth
• The lowest concentration with no visible growth is the MIC

Step 4: Other methods explained.

• Disk diffusion: Gives zone of inhibition, not exact MIC
• Gram staining: Identifies bacteria type
• Streak plate: Used for isolation of colonies

Step 5: Conclusion.
Thus, the broth dilution method is used to determine MIC.