1. Hydrogen Peroxide Influence on Microbial Survivorship
Jacob Cebulak
Central Catholic Pittsburgh
Grade 9

2. Problem
Does hydrogen peroxide affect the survivorship of Escherichia coli and Staphylococcus Epidermidis?

3. Introduction Variable Types of Bacteria Used
Walgreens Hydrogen Peroxide 3%
First Aid Antiseptic
Types of Bacteria Used
Escherichia Coli
Staphylococcus Epidermidis

4. Walgreens Hydrogen Peroxide
First aid to help prevent infection.
For use on minor cuts, scrapes, and burns.
Aids removal of secretions in mouth.

5. E.Coli Rod shaped cells, usually 2 nanometers in length Prokaryotic
Gram-negative
Found in the intestines of many mammals
Commonly used model
Reproduces rapidly, usually within thirty minutes
Many strains, most non-pathogenic

6. Staphylococcus Epidermidis
Bacteria that is mostly harmless and lives normally on skin and mucous membranes of humans
Gram-positive
Many forms are considered non-pathogenic
Pathogenic forms can be lethal

7. Gram+ vs. Gram- Bacteria
Most pathogenic
Simple cell wall.
Antibiotics work against the formation of the cell wall.
Staphylococcus epidermidis
Gram-
The cell wall is a thin layer of lipopolysaccharide, which adds extra protection.
This layer protects the cell from certain antibiotics.
Escherichia coli

8. Recent Studies
Scientists in North Carolina explored the role of hydrogen peroxide in cell health.
Scientists in Oklahoma have studied the role of hydrogen peroxide in environmental adaptation of oral microbial communities.

9. Purpose
The purpose of this experiment was to test the survivorship of microbial bacteria when it was exposed to hydrogen peroxide.

10. Hypotheses
Null Hypothesis: Hydrogen peroxide will not reduce the survivorship of E. Coli and Staph. E.
Alternative Hypothesis: Hydrogen Peroxide will significantly reduce the survivorship of E. Coli and Staph. E.

11. Materials LB Plates Escherichia Coli Staphylococcus Epidermidis Pipets
Walgreens Hydrogen Peroxide 3% Antiseptic
Test Tubes
Vortex
Spreaders
Ethanol
Matches
Bunsen Burner
Sterile Dilution Fluid

12. Procedure
Different solutions were created; 0.001%, 0.01%, 0.1%, 0.5% concentration of hydrogen peroxide, as well as a control. Two of each of these concentrations were created.
Each solution was vortexed.
In each solution, 0.1ml of Staphylococcus Epidermidis was added.
In the other solutions, 0.1ml of the E.Coli was added.
Each solution was vortexed again.
The bacteria were exposed to the solution for 10 minutes before plating.
The solutions were vortexed again and then plated.
The solutions were spreaded immediately after the application to the plate.
The E.Coli plates were incubated for 24 hours.
The Staphylococcus Epidermidis plates were incubated for 48 hours.
Each plate was counted within 24 hours of the removal from the incubator.

13. (Sterile Dilution Fluid)
Concentration Chart
0% HP
0.001% HP
0.01% HP
0.1% HP
0.5% HP
Bacteria
0.1mL
SDF
(Sterile Dilution Fluid)
9.9mL
9.8999mL
9.899mL
9.89mL
9.85mL
(Hydrogen Peroxide)
0mL
0.0001mL
0.001mL
0.01mL
0.05mL
Total
Volume
10mL

14. Escherichia Coli Anova
Anova: Two-Factor Without Replication
SUMMARY
Count
Sum
Average
Variance
Row 1 6
4984
Row 2
2056
Row 3
1659
276.5
1493.9
Row 4
336 56
160.4
Row 5
Column 1 5
1374
274.8
Column 2
1592
318.4
Column 3
1488
297.6
Column 4
1574
314.8
Column 5
1500
300
95960
Column 6
1507
301.4
ANOVA
Source of Variation SS df MS F
P-value
F crit
Rows 4
2.06E-19
Columns
Error 20
Total 29

15. Staphylococcus Epidermidis Anova
Anova: Two-Factor Without Replication
SUMMARY
Count
Sum
Average
Variance
Row 1 6
3868
Row 2
1832
Row 3
1092
182
1003.2
Row 4
208
Row 5 12 2
19.6
Column 1 5
1066
213.2
Column 2
1140
228
Column 3
1223
244.6
Column 4
1322
264.4
Column 5
1112
222.4
Column 6
1149
229.8
ANOVA
Source of Variation SS df MS F
P-value
F crit
Rows 4
2.49E-17
Columns
Error 20
Total 29

16. E.Coli and Staph. E. Survivorship Graph

17. Conclusion
The null hypothesis that hydrogen peroxide would not affect the survivorship of Escherichia coli and Staphylococcus Epidermidis was rejected for all concentrations of H2O2.

18. Extensions Test different brands of hydrogen peroxide.
Test more concentrations of hydrogen peroxide
More replicates.
More species of bacteria

19. Limitations Only tested 2 types of bacteria.
Only had 4 different concentrations.
The plating process could have been more synchronized and careful.