Antibiotic resistant lab

[amurali]

I am confused about effectivnes of antibiotic.
I have completed the lab and I am writing report.

My question is
How do I tell which antibiotic is most effective against this type of bacterium. Which is least effective? How did you determine the level of effectiveness?

My chart of zone of inhibiton using disk test:

Disk Trial 1 Trial 2 Trial 3 Average
A 0.9 0.8 0.7 0.8
B 1.5 1.4 1.3 1.4
C 2.1 2.2 2.2 2.2
D 3 3 3 3
E 4 3.8 3.6 3.8


Please someone explain it to me. I am a Online home schooler.

Thank You

[sunmoonstars]

Hi,

That's great, you have completed the experiment and have data. In order to answer your questions, I found this website very helpful, I want to share:
http://www.antimicrobialtestlaboratorie ... tivity.htm

Basically, the discs with your compounds on it, when placed over the agar plates, will sometimes inhibit microbes from growing there. These orgnisms are susceptible to that (antimicrobial) compound, and there is some relationship between the strength of the compound and the size of the 'zone of inhibition' (the area where nothing grows around the disc).

So, the most effective compound will be the one with the largest zone of inhibition. In order to determine from your data which one, I would average the 4 trials together for your final value.

Does that help? Let me know if you would like more help with this.

Tonya

[MadelineB]

Hello Amurali,
Another way to approach the summary of your data could be to rank the averages for the 5 disks (A through E). You didn't tell us if the antibiotic used was the same in all 5 disks or if the doses varied.

If the antibiotic was different, you could make a plot showing the results for each trial for each of the antibiotics. Alternatively, if you tested the same antibiotic but varied the dose, you could show the dose on the horizontal axis and plot the results on the vertical axis. The website provided by the previous expert explains that the larger the zone of inhibition, the more effective the antibiotic.

Your data suggested that whatever you used in the 3 trials for disk E had a larger zone and thus would seem to be more effective.

Hope this helps! Let us know if you have more questions!