This experiment was conducted in order to observe the different effects that prebiotics, probiotics, and antibiotics can have on E.Coli K12 growth and development. The experiment mimics a person taking these at home, in hopes to prevent or treat pneumonia. This would hopefully help society and the medical field to decrease the chance of people getting sick and help to improve someone’s health if they are sick. It was predicted that the E.Coli K12 with the antibiotic discs would show a decreased amount of growth while the prebiotics and probiotics show an increased amount of growth. There were a total of 4 groups consisting of the control, the prebiotics, the probiotics, and the antibiotics. Different groups and brands of each variable were also compared against one another to see if one would demonstrate significant growth. A petri dish was set up containing agar and then E.Coli K12 and the variable were added which then was cultured for a day before being measured. It was found that antibiotics showed the most inhibition of E.Coli K12 while prebiotics demonstrated the most growth of the E.coli K12. Additionally there was a significant difference between the average growth demonstrated by prebiotics and probiotics. From this experiment it can be concluded that antibiotics are the best inhibitors of bacteria and would be the best option in real life circumstances.
What is the effect of antibiotics, and probiotics on the growth of E-Coli k12?
Day 1 (start trial):
Begin with four petri dishes and using a sharpie, label each with the date, the type of given variable, the brand of that variable and your group initials.
Pull hair back, and put on safety goggles, and gloves.
Remove the agar from the fridge and slightly screw off the top for gas to escape.
Take the agar and begin to slowly melt it in a microwave taking it out periodically and swirling it while wearing a hot hand to avoid the lid popping off and getting burned. (Once bubbles are noticed, or popping is heard take agar out and swirl).
Continue this until the agar is completely melted with no detectable chunks.
Let the agar cool slightly, then slowly pour the agar using the hot hands into the petri dishes until it covers the bottom completely.
Let the agar in the plates settle then flip 40 minutes later.
Day 2 (spread E.Coli and add variables):
The next day using a sterile dropper drop 4 drops of E.Coli onto the center of the agar in each petri dish. Immediately after dispose of the dropper in a biohazard bin.
Use a sterile spreader to lightly spread the E.Coli completely covering the agar in each dish. When complete instantly dispose of the sterile spreader in a biohazard bin.
Take nutrient broth and subculture the E.Coli by taking a pipette and injecting one squirt of E.Coli into the new nutrient broth (which should be labeled with the date) and put it in the incubator.
Take the assigned antibiotic disc out of the fridge and allow it to get to room temperature.
While the antibiotic is warming to room temperature take small weigh boat or weighing paper and place it on a scale.
After placing the small weigh boat or the weighing paper on the scale, zero the scale.
Take the given variable (the prebiotic or probiotic) and using the scale, measure out 1.0 grams of the given variable.
Pour that 1.0g into a mortar and pestle.
Measure 10ml of distilled water using a 10ml graduated cylinder and add it into the mortar and pestle with the given variable.
Using the mortar and pestle crush and mix the variable until it becomes a completely dissolved solution.
Using a sterile dropper put 4 drops of the given solution into the center of the assigned petri dish.
Repeat steps 12-18 for the remaining variable.
Pour the new solutions of the variables (if any) into a glass tube and label that tube with the type of variable and the brand using tape and a sharpie. Store the glass tubes the refrigerator for future testing.
Use alcohol wipes to sterilize tweezers then carefully grab a disc and place it into the assigned petri dish gently pushing it into the agar.
After all variables have been added use petri seal to seal the petri dishes shut. Then place all plates into the incubator.
Day 3 (collect data and begin a new trial):
Take the petri dishes out of the incubator.
Using the centimeter side of a ruler, measure the growth or inhibition (the diameter) and record the results in the data table.
Once all data has been collected repeat Day 1.