Broth Dilution Test: Unveiling the Secrets of Antibiotics

What information can the broth dilution test provide?

a. the rate of diffusion of an antibiotic.
b. the MBC (minimum bactericidal concentration), with an additional step.
c. the MIC (minimum inhibitor concentration).
d. the molecular target of an antibiotic.
e. both the MIC and the MBC (with an additional step).

Answer:

The broth dilution test can determine the MIC and MBC of an antibiotic.

Explanation:

The broth dilution test can provide information for determining the MIC (minimum inhibitor concentration), which is the lowest concentration of an antibiotic that will inhibit the visible growth of a microorganism. The test involves diluting the antibiotic in a series of broth tubes and then inoculating them with the microorganism. The tube with the lowest concentration that shows no visible growth is the MIC.

If an additional step is performed by transferring the broth from the tubes with no visible growth onto agar plates, then the broth dilution test can also determine the MBC (minimum bactericidal concentration). The MBC is the lowest concentration of an antibiotic that kills the microorganism.

Therefore, the correct answer is e. both the MIC and the MBC (with an additional step).