Krista Chloe and Rachel

Project Topic: Salicylic acid and Benzoyl peroxide and their varying effectivity on Eschierichia coli
Chemistry Concept: Acids and Bases, potency


Hypothesis: Benzoyl Peroxide should have a bigger zone of inhibition compared to salicylic acid which was predicted to in the kirby-bauer zone of inhibition study on Escherischia coli because of the results found from a reliable online resource.
Salicylic acid should reduce pore size more than benzoyl peroxide because it contains more acid to dry out the skin.

Abstract:

EFFECT OF BENZOYL PEROXIDE AND SALICYLIC ACID ON ESCHERISCHIA COLI BACTERIA. Chloe Hite, Krista Viksnins and Rachel Ketz. The purpose of this study was to compare the antibiotic qualities of benzoyl peroxide medication and salicylic acid acne medication on Escherischia coli. In doing so, it was possible to infer the effect that the two medications would have on Propionibacterium, the bacteria that cause the skin condition acne vulgaris. The Kirby-Bauer zone of inhibition method was used to study how E. coli bacteria plated on agar Petri plates was either resistant or susceptible to the benzoyl peroxide and salicylic acid acne medications placed on each plate. Theoretically the Propionibacterium bacteria would be susceptible to the medications in the same way the E. coli bacteria were, as they are both gram positive bacteria. The E. coli bacteria were most susceptible to the benzoyl peroxide, as it had the largest zones of inhibition on all three plates, with radii of 9millimeters, 9 millimeters, and 7 millimeters after twenty four hours of incubation. The salicylic acid also had sizable zones of inhibition, though with slightly smaller radii on all three plates at 5, 5, and 8 millimeters respectively after twenty four hours. Therefore it can be concluded that benzoyl peroxide is more potent antibiotic than salicylic acid, though both are effective at killing and preventing growth of bacteria. Another experiment was conducted to test the two medications on chicken skin to measure the decrease in pore size. It was predicted that salicylic acid would be more effective because of its acid content in the medication, thus drying out the skin and reducing the pore size. The data results supported this because salicylic acid had average pore sizes of 4.2mm before the medication was applied and refrigerated for 24 hours, and 3.2mm after the medication was applied. The benzoyl peroxide treated chicken had pore sizes of 4.5mm before their application, and average pore sizes of only 3.9mm afterward. This data may be studied further and applied in the field of dermatology to synthesize effective anti-bacterial acne medications to prevent against the bacteria that create the common skin condition acne vulgaris.

Key words: zone of inhibition, benzoyl peroxide, salicylic acid, E. coli, Propionibacterium, gram positive, antibiotic, pH, acne vulgaris.
Journal Article:
http://web.ebscohost.com/ehost/detail?vid=4&hid=104&sid=2a5296be-a6f4-4743-89e0-fe4bc1a69971%40sessionmgr104&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=aph&AN=36551493
http://web.ebscohost.com.proxy.elm4you.org/ehost/search/basic?sid=cde3ea67-f119-4787-98c7-52ad94ba859b%40sessionmgr13&vid=1&hid=8
http://discovery.kcpc.usyd.edu.au/9.2.1-short/9.2.1_FRP.html
http://en.wikisource.org/wiki/Popular_Science_Monthly/Volume_7/October_1875/A_New_Antiseptic
http://www.hhmi.org/biointeractive/Antibiotics_Attack/bb_1.html

The two medications:
http://www.drugstore.com/products/prod.asp?pid=139460&catid=182284&aid=338666&aparam=139460
Clearasil Ultra Daily Face Wash Acne Medication
Clearasil Ultra Daily Face Wash Acne Medication

and
http://www.neutrogena.com/product/clear+pore+cleanser-mask.do?sortby=ourPicks&page=2
Clear Pore Cleanser/Mask
Clear Pore Cleanser/Mask


Bissonnette, R. R., Bolduc, C. C., Seité, S. S., Nigen, S. S., Provost, N, N., Maari, C. C., & Rougier, A. A. (2009). Randomized study comparing the efficacy and tolerance of a lipophilic hydroxy acid derivative of salicylic acid and 5% benzoyl peroxide in the treatment of facial acne vulgaris. Journal Of Cosmetic Dermatology, &(1), 19-23.

Acne. (n.d.). The American Heritage® Science Dictionary. Retrieved February 26, 2012, from
Dictionary.com website: http://www.dictionary.reference.com/browse/acne

Acne. (n.d.). University of Maryland Medical Center. Retrieved March 4, 2012, from http://www.umm.edu/altmed/articles/acne-000001.htm
"A New Antiseptic." Popular Science 7 (1875): n. pag. http://wikisource.org. Web. 5 Mar. 2012.

Bissonnette, R. R., Bolduc, C. C., Seité, S. S., Nigen, S. S., Provost, N, N., Maari, C. C., &
Rougier, A. A. (2009). Randomized study comparing the efficacy and tolerance of a lipophilic hydroxy acid derivative of salicylic acid and 5% benzoyl peroxide in the treatment of facial acne vulgaris. Journal Of Cosmetic Dermatology, &(1), 19-23.

Bowen, R. (n.d.). Free Radicals. Biomedical Sciences. Retrieved March 4, 2012, from http://www.vivo.colostate.edu/hbooks/pathphys/misc_topics/radicals.html

Brüggemann, H. (2010). Proteomic identification of secreted proteins of Propionibacterium acnes. BMC Microbiology, 10(230). Retrieved March 4, 2012, from the BMC Microbiology database.

Oh, S. (n.d.). Antibiotics attack. Biointeractive. Retrieved March 4, 2012, from http://www.hhmi.org/biointeractive/Antibiotics_Attack/bb_1.html

Lab Procedure:
-Prepare agar plates
  • Mix chemicals in flask
  • Add water
  • Cook in sealed oven
  • Allow to cool
  • Fill Petri dishes sterilely
  • Restack dishes
  • Allow agar to solidify in dishes
-insert bacteria into plates
Apply salicylic acid or benzoyl peroxide to bacteria
-record results after colonies of bacteria have been diminished and counted

Second Procedure:
-Use store-bought skin-on chicken and apply acne medications
  • smear a light layer of acne medication on the chicken
-refrigerate for 24 hours and then re-measure pore sizes with a ruler under a microscope
  • record data and depose properly


Apparatus and Chemicals Needed:
-Bunsen Burner
-oven
-Petri dishes
-agar
-live unharmful bacteria
-erlenmeyer flasks
-microscope
-crepe spreader to spread agar and anti-bacterial solution
-store bought chicken with skin

Safety Information:
-Take extra care with heated objects
-wear goggles
-sterilize everything
-be aware of flames/hot objects
-tie hair back
-be sterile with bacteria (i.e. wash hands, wear gloves, etc.)
-do not touch eyes after handling acids
-be aware of acids you are working with
-clean glassware
1. liquid broth pour onto prepared solidified agar plate (not an even lawn?)
2. mix liquid broth and cooled gelled agar and then pour on plate (burn and kill?)

Notes:
  • Bacterial plate study
  • Zone of inhibition
  • how to make agar?
  • what to do with bacteria?
  • name of spreading tool?

Our mascot:
Cute hedgehog
Cute hedgehog