1. Effects of Acne Medications on E. Coli
Lewis Richardson
Central Catholic High School
Grade 9

2. What effect do acne medications have on the survivorship of E. coli?
Problem
What effect do acne medications have on the survivorship of E. coli?

3. Hydrogen Peroxide (3%)
One of the most commonly used chemicals for sterilization.
Targets germs such as staph, strep, Salmonella, and E. coli.
Used for clearing acne, whitening teeth, lightening hair, and other common uses around the house.

4. Salicylic acid (0.5%)
One of the most commonly used chemicals for treating acne.
Colorless crystalline organic acid
Widely used in organic synthesis and functions as a plant hormone.

5. Escherichia Coli Large and diverse group of gram (-) bacteria.
Surrounded by an extra cell wall composed of lipopolysaccharides.
Free living, symbiots, or pathogens.
Common prokaryotic cell model.
Most are not pathogenic.

6. Acne Vulgaris Common human skin disease
Areas of skin with seborrhea (scaly red skin), comedones (blackheads and whiteheads), pimples, and possible scarring
Excess amount of sebum and dead skin cells: bacteria can thrive
Caused by bacteria, hormones, diet, stress, and medications
Anaerobic bacteria P. acnes, found in sebaceous glands, attributed to acne
Treated by over-the-counter and prescription medications in the form of a pill or wash

7. Purpose
Determine which type of acne medication works the best at a given concentration.

8. Previous Studies
Experiment conducted by the University of Southern California on the effects of home remedy acne methods in comparison to professional products.
Proactiv tests run using E. coli as an acne substitute

9. Hypothesis
Null: The variables will not alter the growth or survivorship of E. coli.
Alternative: increasing concentrations of the variables will significantly reduce survivorship of E. coli.

10. Materials Hydrogen Peroxide (3%) E. coli DH5 Alpha
LB agar plates
Micropipettes
Sterile Pipette tips
Sterile Test Tubes
Sterile Spreader Bars
Incubator
Bunsen burner
Hydrogen Peroxide (3%)
Salicylic Acid (0.5%)
SDF (Sterile Dilution Fluid), (100 mM KH2PO4, 100 mM K2HPO4, 10 mM MgSO4, 1 mM NaCl)
Vortex
Ethanol (sterilization of instruments)
Matches

11. Procedure
Labeled all plates and flasks before experimentation with "Control, 0.1%, 1%, 5%, & 10%."
The variables, microbe, and SDF were added to create mixtures with the desired concentrations:

12. Toxic Agent (Acne Medication)
Mixtures
Control Variable
0.1% 1%
10%
Sterile Water
9.9 mL
9.89 mL
9.8 mL
8.9 mL
Toxic Agent (Acne Medication)
0 mL
0.01 mL
0.1 mL
1 mL
E. Coli

13. Procedure (cont.)
3. Dipped spreader into ethanol and burned with matches or Bunsen burner to sterilize it.
4. Evenly spread the mixture on the plate with the sterile spreader bar.
5. Closed the plate and put into incubator to allow overnight growth
6. Counted the colonies that have grown on the plates

14. What is an ANOVA?
An ANOVA test is used to search for significant variance between data
Used to determine if there is significant variation between the mean values of groups
If the P- value is smaller than the alpha value (.05), then at least two of the means varied significantly

15. Hydrogen Peroxide Effect on E. Coli Survivorship
P Value=1.02E-14

16. Dunnett's Test (Hydrogen Peroxide)
T-Critical=4.0
Variable Concentration
T-Values
Significant?
0.1%
3.596
Not Significant 1%
32.6
Significant
10%
37.0

17. Salicylic Acid Effect on E. Coli Survivorship
P-Value=
Concentrations of acne medications

18. Dunnett's test (Salicylic acid)
T-Critical=4.0
Variable Concentration
T-Value
Significant?
0.1%
3.59
Not Significant 1%
2.80
10%
11.2
Significant

19. Conclusions
The 1% and 10% concentrations of hydrogen peroxide significantly lessened the E. Coli survivorship while 0.1% was not significant.
The 10% concentration of Salicylic acid significantly lessened the E. Coli survivorship while the 0.1% & 1% did not.
Reject the Null Hypothesis, Accept the Alternative hypothesis.

20. Limitations Only one model used
Test tubes may have been contaminated when plating mixtures.
Only survivorship was tested
Only two kinds of acne medications used

21. Extensions
More acne products could have been used with more varying concentrations.
More replicates could have been used to ensure human error or contamination was not a factor in the suvivorship.
A growth analysis could have been conducted
Synergistic effects with other drugs
Vary exposure times
Agar infusion or surface wipe exposure

22. Works Cited Salicylic Acid.” ChemistryDaily.com. Web. 24 Dec. 2014
“CLINDAMYCIN PHOSPHATE lotion CLINDAMYCIN PHOSPHATE solution CLINDAMYCIN PHOSPHATE gel” Daily Med Current Medication Information. Web. 24 Dec. 2014
Fredrick, Kurt, Shinichiro Shoji, and Sarah E. Walker. “Ribosomal Translocation: One Step Closer to the Molecular Mechanism.” ACS Chem. Biol Web. 24 Dec. 2014
Guay, David RP. “Topical clindamycin in the management of acne vulgaris.” Web. 24 Dec. 2014
Kishi, Kenji, and Kazyhiro Hirai. “Clindamycin Suppresses Endotoxin Released by Ceftazidime- Treated Escherichia coli O55:B5 and Subsequent Production of Tumor Necrosis Factor Alpha and Interleukin-1 β.” Antimicrobial Agents and Chemotherapy Web. 24 Dec. 2014
Nishijima, S, I Kurokawa, N Katoh, and K Watanabe. “The bacteriology of acne vulgaris and antimicrobial susceptibility of Propionibacterium acnes and Staphylococcus epidermidis isolated from acne lesions.” n. p. Web. 24 Dec. 2014
Owens, CD, K Stoessel. “Surgical site infections: epidemiology, microbiology and prevention.” Journal of Hospital Infection Web. 24 Dec. 2014

23. ANOVA (Hydrogen Peroxide)

24. ANOVA Salicylic Acid

25. ANOVA (0.1% concentrations)

26. ANOVA (1% concentrations)

27. ANOVA (10% concentrations)