Page 80 - MNU PM502 Ph. Micreo practical

Pharm D- Clinical Pharmacy Program Third Level Pharmaceutical Microbiology& Antimicrobials (PM 502)

Steps:

1. Mark the empty test tubes 2, 3, 4, 5, positive, negative control and mark the

antibiotic test

tubes 1.

2. Preparation of two-fold serial dilution for antibiotic A:

➢ Transfer 2 ml of N. broth into the empty test tubes (2, 3, 4, 5, positive and

negative control) starting with negative control.

➢ Transfer 2 ml from tube A to tube 2, mix well & from 2 to 3, mix well & repeat

this for 4 & 5, then reject 2 ml from test tube 5.

3- Add 0.2 ml culture to all tubes except negative control (tubes A, 2, 3, 4, 5 &

positive control).

4- Incubate the tubes at 37˚C for 24 h and determine the bacterial growth.

5- Calculate the MIC.

Role of Positive and Negative Controls:

Positive control: Broth+ culture

• Test the ability of the medium to grow the microorganism.

Negative control: broth only

• Test the sterility of the medium.

67