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

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

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

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

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

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

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

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.

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

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.

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

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.

(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

Escherichia Coli Anova Anova: Two-Factor Without Replication SUMMARY Count Sum Average Variance Row 1 6 4984 830.6667 1725.867 Row 2 2056 342.6667 3415.467 Row 3 1659 276.5 1493.9 Row 4 336 56 160.4 Row 5 Column 1 5 1374 274.8 110691.2 Column 2 1592 318.4 125359.3 Column 3 1488 297.6 109550.8 Column 4 1574 314.8 102852.7 Column 5 1500 300 95960 Column 6 1507 301.4 112853.8 ANOVA Source of Variation SS df MS F P-value F crit Rows 2601054 4 650263.5 464.1888 2.06E-19 2.866081 Columns 5960.967 1192.193 0.851044 0.530171 2.71089 Error 28017.2 20 1400.86 Total 2635032 29  

Staphylococcus Epidermidis Anova Anova: Two-Factor Without Replication SUMMARY Count Sum Average Variance Row 1 6 3868 644.6667 4796.267 Row 2 1832 305.3333 1367.467 Row 3 1092 182 1003.2 Row 4 208 34.66667 149.8667 Row 5 12 2 19.6 Column 1 5 1066 213.2 51484.7 Column 2 1140 228 61590.5 Column 3 1223 244.6 73153.8 Column 4 1322 264.4 93676.8 Column 5 1112 222.4 55476.8 Column 6 1149 229.8 76712.2 ANOVA Source of Variation SS df MS F P-value F crit Rows 1619982 4 404995.5 285.2349 2.49E-17 2.866081 Columns 8284.667 1656.933 1.166964 0.359572 2.71089 Error 28397.33 20 1419.867 Total 1656664 29  

E.Coli and Staph. E. Survivorship Graph

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.

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

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