What Is The Kirby-Bauer Method?

The results of this experiment ended up being very conclusive and not positively or negatively surprising. The data and results collected we what we had expected more importantly the ones on the X-Gal plates where the colonies were above 100. Both the stains of E. Coli grew colonies when they were in the LB. When the ampicillin was present the cells did not grow even with the X-gal. The transformed cells on the other hand grew when the ampicillin was there. When the X-gal and AMP were present the transformed cells grew and had a blue tint, which is why we call it the pBlu lab. (duh)

In order to determine which ones would be resistant, intermediate, and susceptible to our unknown strain of E. coli we had three antibiotics and one control per agar plate, and we replicated this twice. A lawn of the E. coli strand was spread evenly on each agar plate with a cotton swab. We then divided the agar plate into four halves and placed an antibiotic sample in each half with forceps. We incubated the dishes for forty-eight hours. Our independent variables are the different types of antibiotics with our known and unknown E. coli that we used to conduct the experiment and our dependent variables are the diameters of the zone of inhibition for each antibiotic.

The development of the scientific method in the late 1500’s to the early 1600’s was a crucial stepping-stone in the science community. The scientific method is based upon observations, hypotheses and experimentation. The concept is rather simple, and can be applied to many areas of study. Once an observation is made, the observer can make a hypothesis as to why that phenomenon occurs and can then design an experiment to prove whether or not that hypotheses is valid. Although the scientific method has been extremely useful in the discovery of various things from usages of medications to studying animal behavior, there are still those who question the usage of this tool. These critics claim that since

Gold standard procedures should be implemented with the aim of providing timely and accurate results. (Schentag) The culture result should be accompanied by its clinical significance, selective reporting of susceptibility testing results in accordance with hospital antimicrobial therapy guidelines and suggested management. (Schentag) This encourages appropriate prescribing and minimises unnecessary use of antimicrobials. The clinical microbiology team should also provide reports to AMS regarding resistant organisms.

Many tests were completed on the unknown such as gram staining and inspection under microscopes to find whether the bacterium is gram positive or gram negative. Chemical resistance tests were also performed to see if certain chemicals affected the unknown growth or if it didn’t affect the bacteria at all. Each biochemical test

The Kirby-Bauer antibiotic tests indicated that the unknown is susceptible to chloramphenicol and ampicillin and resistant to penicillin G and tetracycline. The disinfectant sensitivity tests indicated that C. Freundii is resistant to all four of the disinfectants.

Ampicillin, penicillin, streptomycin all sulphafurazole all were resistant to the bacteria as it may have grown a mutation.

When investigating this experiment I found many different types of antiseptics all with different effects on bacteria and the effectiveness of all these antiseptics varied. I found

The bacteria has ampicillin resistance gene and can either have no RNAi insert (control plate) or PCR product that is a portion of target gene (unc-22).

E.coli outbreaks have steadily grown over the last few decades. An expansion in big farming has led to E. coli not only being found in meat, but vegetation as well, due to waste runoff. This has increased our need for adequate antibiotics that can fight bacteria, like E. coli. The best way to pinpoint which antibiotics work is by measuring their ability to create antimicrobial agents or zones of inhibition. When a paper disc that has been saturated in an antibiotic is inserted in a solution of E.coli and medium, the zone of inhibition will be noted as the clear ring that forms around the disk. The antibiotics efficacy is then determined by measuring each disk zone of inhibition, and comparing these measurements to the zone measurements of an untreated specimen. If an antibiotic is to be deemed sufficient for treating E. coli it should show a zone of inhibition that is at least double the size of the untreated specimen.

I believe that the test that we performed was not effective in distinguishing between bacteriostatic and bactericidal agents because there is no distinguishing characteristics between the zone of inhibition of a bacteriostatic agent and a bactericidal agent.

The problem that this experiment is trying to solve is whether or not Staphylococcus epidermidis is resistant or susceptible to various antibiotics. The independent variable for the experiment is the type of antibiotic being used against the bacteria(Ampicillin, Streptomycin, Penicillin, and Tetracycline). The

There were two controls in place during this experiment. The first control was the –pGLO LB plate; which showed that without inserting a plasmid into the bacteria, that bacteria would not be able to glow. The second control was the –pGLO LB/AMP plate; which showed that bacteria that did not contain the plasmid containing the ampicillin resistant gene could not survive in an environment with ampicillin preasent. This experiment had two constants; which were, that we incubated all of the bacteria cultures at the same temperature and the fact that we used the same type of bacteria for all of the plates. A potential sources of error in this lab is that the bacteria could have gotten contaminated from being exposed to air and debri falling into the plate.

The Kirby-Bauer disc diffusion method was used to examine sensitivity of antimicrobial agents, it fast and simple way to find an antibiotic to use for a treatment of some type of infection. This method uses a plate that has been cover with the testing bacteria and small disc covered in the antibiotic to see if the bacteria is able to around the disc, it will make an even circle around the disc which is the zone of inhibition. This zone of inhibition diameter can be measured and compared to the interpretation chart to find the antibiotic sensitivity or resistance. When the zone of inhibition is very small or nonexistent this shows that bacteria is resistant to the antibiotic and will not work against this bacterial infection. If the zone is

The main objective of this experiment is to investigate the effect of different types of antibiotics on bacteria Bacillus subtilis and Escherichia coli. Some of the main methods used in this experiment