Micro lovers I NEED YOUR HELP PLEASE!!

Nursing Students General Students

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Specializes in Med Surg/Tele/ER.

My lab experiment was streak 3 plates one with E. coli, another with S. epidermidis & one with B. cereus. Then put 5 disks in each soaked with 95% alcohol, 50% alcohol, 3% hydrogen peroxide, 3.2% gluteraldehyde & 10% clorox.Measure the growth of bacteria for each one, peroxide inhibited the growth better than any of them. I thought that the clorox would! Now I have to write a paper & explain how this happened. I have googled myself to death & read & read and cannot explain it :crying2: . I think it has to do with the thickness of products used & the cell walls but I don't know how. I really need help if any one can explain this I will be forever grateful!! Thank you

Specializes in NICU/Neonatal transport.

Non-catalase producers possibly? I don't have my notebook right here with me with my info in it, but if they can't produce catalase, that would cause H2O2 to be very effective against them. But I could have sworn that E. coli was a catalase producer, so H2O2 shouldn't have been effective against it. E. coli is also a G- bug, which makes it harder to kill.

What were your zones of inhibition for each plate?

Specializes in NICU/Neonatal transport.

Looking it up, all three are catalase producers, which means they can deal with h202 fairly easily. Are you sure you had everything labelled correctly?

Specializes in Med Surg/Tele/ER.
Looking it up, all three are catalase producers, which means they can deal with h202 fairly easily. Are you sure you had everything labelled correctly?

E. coli S. epidermidis B.cereus

95% alcohol--- 6mm 6mm 12mm

50% alcohol--- 6mm 6mm 6mm

h2o2 3%--- 26mm 40mm 44mm

Gluteraldehyde--- 16mm 14mm 18mm

Clorox 10%--- 8mm 6mm 8mm

Yes there were correctly labeled our instructor was all over it. We then went over all our results in class & any that were out of range the instructor & student went back over them. If you have any more ideas I'm all ears. Thanks so much

Specializes in OB, lactation.

Wish I could help you... I took Micro almost 3 years ago so it's no very fresh in my memory!! Hope you figured it out. :)

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