1. Melt 0.6% agar/LB (autoclaved).

2. Cool the agar/LB to ~50 °C. Add antibiotics.

3. Pipet 10 ml agar/LB/antibiotics to a sterile 15 ml culture tube.

4. Cap and lay the tubes on the side (the cap end higher) and wait until the agar sets completely (~1 hr).

5. Take a sterile inoculating loop, pick a colony (or dip into the culture). Pierce the agar to the bottom of the tube several times.

6. Incubate overnight with a loose cap at 37°C.