1. Effects of Facial Cleaner on E. coli and Staph
By Ryan Dillon
Central Catholic High School
Grade 9

2. Problem
With cosmetics being investigated, does Cetaphil Facial Cleaner have an effect on normal human microbial flora?

3. To test the effects of Cetaphil facial cleaner on E.coli and Staph
Purpose
To test the effects of Cetaphil facial cleaner on E.coli and Staph

4. Microbial Flora
Little is known about the association between humans and their flora
Effects are mutualistic, parasitic, pathogenic and commensal
Provide nutritional and digestive benefits, secrete vitamins, stimulate antibody production, and protect against pathogenic microbes

5. Hypotheses
The null hypothesis of the experiment is that the facial cleaner will not have an effect on the growth of E. Coli and Staph
The alternative hypothesis is that the facial cleaner will have an effect on the growth of E. Coli and Staph

6. Escherichia Coli Major cause of food-borne illness
70,000 cases/year in U.S.
Consumption of undercooked meats
Consumption of contaminated vegetables or unpasteurized milk
Also resides in fecal matter.
Most studied bacteria
Resides in the digestive tract of animals.
Can survive outside of host organism
Not all strains of E.coli can result in sickness or disease

7. Staphylococcus Epidermidis
Staph is a Gram-positive bacterium
Part of the normal human flora, usually the skin flora
Not usually pathogenic but can be if a person with a weakened immune system is infected
Patients usually infected through hospitals

8. Prevention and Treatment of E.Coli
Washing hands
Thorough cooking of food
Washing food
Food employees washing hands and wearing gloves
Antibiotics

9. Materials Permanent Marker Vortex Incubator Sterile tips Tube Racks
Micropipettes P1000 and P200
E. coli
Staph
Sterile Luria broth Agar Plates (1% Tryptone, 0.5% Yeast Extract, 1% NaCl)
Spreaders
Ethanol
10% Stock Clearasil Facial Cleaner
Permanent Marker
Vortex
Incubator
Sterile tips
Tube Racks

10. Procedure
Both bacteria were grown until a density of 50 klett spectrophotometer density was reached. This was approximately 10^8 cells/mL
Both cultures were diluted in sterile dilution fluid to a concentration of approximately 10^5 cells/mL
Took a 10% stock of the Cetaphil Facial Cleaner
Concentrations were then added to the test tubes and then 0.1 ml of bacteria were added to their tubes.
The concentrations were vortexed then added to the plates. (Multiple people spread plates at the same time to prevent lag time)

11. Results Percentage of variable E. coli Staph Control 341 210 O.1% 299
267 1%
274
164 5% 93
140
10% 70
128

12. Number of Colonies
P-Value of Staph – 1.4e-05
P-Value of E. coli – 0

13. Dunnett’s Test Results: Staph
Concentration
T-Value
T-Critical
Results
0.10%
1.59
3.48
Non significant 1%
3.69
Significant 5%
5.60
10%
6.20

14. Dunnett’s Test Results: E. coli
Concentration
T-Value
T-Critical
Results
0.10%
1.69
3.48
Non Significant 1%
5.11
Significant 5%
18.75
10%
21.44

15. Conclusions
The conclusion of this experiment is that the higher the concentration the less bacteria could grow and survive. The alternate hypothesis was significant in all the concentrations for both bacteria besides 0.10%

16. Limitations/Extensions
Limitations: High concentrations not tested, Only two species were tested, and slight variation in the spreading of the plates.
Extensions: More trials, Different concentrations, using yeast, algae, or other bacterium, and two variables not just one

17. One-Way Anova of Staph

18. One-Way Anova of E. coli

19. Works Cited
Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 21 Dec Web. 27 Jan
"Staph Infection (Cellulitis) Contagious, Causes, Symptoms, Diagnosis, and Treatment of Staph Infections." WebMD. WebMD, n.d. Web. 27 Jan
"E. Coli Bacteria Infection Symptoms, Causes, Treatments." WebMD. WebMD, n.d. Web. 27 Jan