The ten Petri dishes that exclusively did not contain an antibiotic in the bacteria culture served as the control. There were ten trials for the control and each level of IV. The experiment began by cleaning the work area and sterilizing it with 70% ethanol. Then trypticase soy agar (TSA) was poured into six groups of 60 Petri dishes (See Appendix 1). The dishes were labeled based on the antibiotic used and were left to dry and solidify at room temperature. After an hour, the dishes were placed in a refrigerator at three degrees Celsius. If there was visible condensation on the agar plate, they were flipped to avoid the contact of heat that drove the moisture out of the agar dishes. The contents of the broth culture of E. coli was gently swirled…
coli on the plates of TSA. The swab was dipped into the test tube containing the E. coli bacteria culture and was swiped delicately over the agar surface of the 60 Petri dishes (See Appendix 2). In order to ensure that the entire surface area of the dish was covered, the E. Coli bacteria culture was swabbed in at least 3 different…
The procedure allowed for the IV to be controlled because of the incubation. This allowed the Petri dish to stay sterile and also protected against foreign bacterial exposure during the incubation. After 24 hours, the Petri dishes were removed from the incubator and were inspected for antibiotic activity. To calculate and measure the antibiotic activity, the Kirby-Bauer disc diffusion antibiotic sensitivity test was used. Each of the Petri dishes were inspected for an inhibition zone, the area around the antibiotic disc where there is no bacterial growth (See Appendix 3). This accurately and effectively measured the susceptibility of a bacteria to an antibiotic because as the antimicrobial diffused out from the disc into the agar, there was a higher concentration nearer the disk. The concentration decreased gradually, as the distance from the edge of the disc increased. As long as the concentration of antibiotic at any given distance is high enough to properly act as an antibacterial agent, no bacteria will grow at that location. Hence, if the bacteria have increased resistance, a smaller inhibition zone would be observed, and vice…
