Help with bacteria experiment!

[agalla]

We are wanting to test 4 different bandages to see whick will inhibit bacteria best. we plan to use petri dishes and agar. Not sure how to go about this experiment. should we place the bandage in the petri dish? Where do we get the bacteria? Help!!! Any ideas to steer us in the right direction on this project? :confused:

[ecoli]

why would you expect bandages to inhibit bacterial growth?

[agalla]

sorry...We were planning to use antibacterial bandages? I'm going into 4th grade and looking for a cool experiment in the medical field? If my bandage idea is not good ..any other ideas??? I really like science!

[ecoli]

you can buy the stuff at a relatively inexpensive cost:

http://www.hometrainingtools.com/catalog/life-science-biology/cat_agar-petri-dishes.html

 

Or here: http://www.sciencecompany.com/sci-exper/petridishes.htm

This link includes good advice on handling bacteria safely.

 

If you don't want to spend the money, there are plenty off ways you can prepare the media from materials from the kitchen: http://www.disknet.com/indiana_biolab/b029.htm

 

Good luck.

[agalla]

Thanks! I will look at those. Do you think my bandage experiment will work? or is it too lame?

[ecoli]

Thanks! I will look at those. Do you think my bandage experiment will work? or is it too lame?

If it's antibacterial then it should work. It could be interesting to compare the effectiveness between different brands.

 

You could culture bacterial samples directly from your skin (you can compare different people's skin as well) and place the bandage down on the plate.

 

Surrounding the bandage should be (if the experiment works correctly) an area where the surrounding bacteria is killed by the antibiotic (don't forget to also use a non-medicated control). By measuring the cleared area, also known as the 'zone of saturation' you can semi-quantitatively compare the effectiveness of the anti-microbials.

 

Another interesting thing you can look at (perhaps more interesting than comparing brand types) is the potential evolution of antibiotic resistance against the bandages. (I can explain further how you could potentially do this, if it sounds interesting to you).

The evolution of antibiotic resistance is a very important detail in medicine these days, as bacteria are able to overcome our medicines faster than we can design them.

If you could show that the anti-biotic bandages are not useful in protecting against bacteria in successive generations, it could help serve as a warning to those, against the overuse of anti-microbial products. (a very important lesson, indeed).

[agalla]

Thank you for the great advice!! I will look at the sites and order my materials. Wish me luck!!

[agalla]

I found out where to get the petri dishes and agar. Do you think this will work? I plan to test 4 different brands of antibacterial bandages and use 1 plain bandage as my control. I think I should remove the sticky part of the bandages using only the pads. I plan to swab my mouth for bacteria and rub onto the bandage pads and place them in the petri dish and store them in a warm place undisturbed. after about 48 hours I will check for bacterial growth. I can measure with a metric ruler? Any thoughts about if this will work as a good science project. I haven't worked with agar or petri dishes ...I want to try to do it correctly for my summer project. I am in the 4th grade

[ecoli]

no matter what way you do it, it's probably not going to work perfectly the first time you do it, so be prepared to repeat your experiment at least a couple of times.

 

I think it's a good idea to just use the soft part of the bandages, since I don't think the rest would have the antibiotics anyway.

 

So, you're project is to compare the antimicrobial activity of each brand?

 

Why would you test it from your mouth bacteria, since, the bandages are going on your skin, afterall.

[Snail13579]

To test which bacteria grows the best, look for the darkest colour.

[ecoli]

To get a semi-quantitative measurement of the relative antibiotic strength, you should measure the zone of saturation around the bandage. Bacteria away from the bandage aren't going to "get" any antibiotics, so their growth won't tell you anything about the antibiotic.

[agalla]

CooL!! I think I've got it!! One LAST question (Promise!!) Should the pads face up or down in the petri dish? I am ready to rock on this experiment!! THANK YOU FOR ALL YOUR HELP!!!

[ilovebacteria]

I wouldn't put bacteria onto the bandages - the bandages are designed to stop bacteria from growing on a wound and I doubt anything would grow on a normal bandage.

 

Check out the pic below, it shows zones of inhibition on an agar plate caused by disks containing an antibiotic. Your experiment would work the best if you try something like this. You would need to spread bacteria over an entire plate and place small pieces of your bandages face down on top. Then let the bacteria grow and then measure the zone of inhibition - this is the area where bacteria haven't been able to grow on the plate. Try with lots of pieces of bandage and work out an average, then compare to other makes of bandage.

 

 

http://en.wikipedia.org/wiki/Image:Staphylococcus_aureus_%28AB_Test%29.jpg

[ecoli]

I wouldn't put bacteria onto the bandages - the bandages are designed to stop bacteria from growing on a wound and I doubt anything would grow on a normal bandage.

 

I don't think he ever intended to. And besides, this thread is months old. I don't think the OP is coming back to read this.

[agalla]

I haven't done this experiment yet....I was just doing research on it over the summer. I will be doing it soon and let you know how it turns out . I am excited about this experiment and can't wait to get started. I wanted to do it correctly so I don't waste alot of money on supplies by not doing it right.