In this experiment we chose to grow ampicillin resistant strains of E. coli on plates of with fixed concentrations of ampicillin. By doing this, we hoped to see an increase in the resistance of the E. coli to the concentrations of ampicillin. We had a steady concentration of ampicillin, ten micrograms for each trail. We plated cultures of E. coli bacteria and then added the disc of ampicillin to the plate. During this experiment we chose to grow E. coli on agar plates with designated concentrations of ampicillin, and let them set overnight in a cool, dry place. After this time, we measured the zone of inhibition around the disc of ampicillin. Then we scraped E. coli from around the zone of inhibition and put these new bacteria into onto new agar plates, adding the same amount of ampicillin. Over two weeks we were able to get five cycles of the resistance testing in. We observed the data and got results, which were minimal. The trials at first showed signs of decreasing zones of inhibition, which is a sign of resistance, however after sometime they stopped. Around the fourth and fifth trial for much of our data we saw that the ampicillin had little effect. If was truly the result restance to ampicillin, it happened much faster than we had expected. Overall, we determined that our results needed further experimentation because the ampicillin used in the experiment had very little effect on the bacteria.

Research Done By:

Jennifer Knirk
Sterling Heights High School

Erika Penabaker
Fitzgerald High School