Effects of Acne Medications on E. Coli

Lewis Richardson Central Catholic High SchoolGrade 9

Problem

What effect do acne medications have on the survivorship of E.

coli?

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.

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.

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.

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

Purpose

Determine which type of acne medication works the best at a

given concentration.

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

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.

Materials• 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

Procedure

1. Labeled all plates and flasks before experimentation with "Control, 0.1%, 1%, 5%, & 10%."

2. The variables, microbe, and SDF were added to create mixtures with the desired concentrations:

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 0.1 mL 0.1 mL 0.1 mL 0.1 mL

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

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

Hydrogen Peroxide Effect on E. Coli Survivorship

Control 0.1% 1% 10%0

200

400

600

800

754 753

913

Concentrations of Acne Medications

Nu

mb

er

of

Su

rviv

ing

Colo

nie

s

P Value=1.02E-14

Dunnett's Test (Hydrogen Peroxide)

Variable Concentratio

n

T-Values Significant?

0.1% 3.596 Not Significant

1% 32.6 Significant

10% 37.0 Significant

T-Critical=4.

0

Salicylic Acid Effect on E. Coli Survivorship

Control 0.1% 1% 10%0

200

400

600

800

754681 697

527

Concentrations of Acne Medications

Nu

mb

er

of

Su

rviv

ing

Colo

nie

s

P-Value= 0.013546

Dunnett's test (Salicylic acid)

Variable Concentratio

n

T-Value Significant?

0.1% 3.59 Not Significant

1% 2.80 Not Significant

10% 11.2 Significant

T-Critical=4.0

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.

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

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

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. 93-107. 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. 616-622. 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 2008. Web. 24 Dec. 2014

ANOVA (Hydrogen Peroxide)

ANOVA Salicylic Acid

ANOVA (0.1% concentrations)

ANOVA (1% concentrations)

ANOVA (10% concentrations)