Question

A clinical microbiologist makes serial dilutions of several antimicrobials in broth, and then incubates each drug dilution series with a standard amount of a patient's isolated pathogen. What is this microbiologist setting up?

A. Kirby-Bauer technique
B. antibiogram
C. E-test
D. minimum inhibitory concentration (MIC) test
E. therapeutic index (TI)

Answer 1

The microbiologist is conducting a minimum inhibitory concentration (MIC) test to determine the lowest concentration of an antimicrobial that inhibits the growth of a pathogen.

Step-by-step explanation:

The microbiologist is setting up a minimum inhibitory concentration (MIC) test. By preparing a series of dilutions of antimicrobials in broth and incubating them with a pathogen, they aim to find the lowest concentration of the drug that inhibits visible bacterial growth. This is a crucial step in antimicrobial susceptibility testing. MIC is observed by the absence of turbidity in the broth, indicating that bacterial growth has been inhibited. Following this, samples from tubes without turbidity are then cultured on agar without antibiotics to determine the minimal bactericidal concentration (MBC), if needed.