The Effects of antibacterial hand soap on bacteria survivorship David Lukac Grade 9 Pittsburgh Central Catholic High School

Problem People all over the world use hand soap to clean themselves Does an antibacterial hand soap significantly affect the survivorship of human microflora Problem

Escherichia coli Major cause of food-born illnesses From consumption of undercooked meats and contaminated or unpasteurized milk Not all strands of E. coli result in disease or sickness Also resides in fecal matter and digestive tract of animals Very commonly used in the lab Gram-negative bacteria Escherichia coli

Staphylococcus epidermidis Part of the normal human flora Typically the skin flora and more rarely with the mucosal flora Associated with intravascular device infections Gram-positive bacteria Staphylococcus epidermidis

Variable Personal Care antibacterial hand soap Triclosan free Active ingredient is Chloroxylenol Water, sulfate, citric acid, ammonium chloride (inactive) Use is for hand washing to decrease bacteria on the skin May cause irritation and redness Variable

To determine the effect hand soap has on the survivorship of Staph e To determine the effect hand soap has on the survivorship of Staph e. and E. coli Purpose

Null hypothesis: The antibacterial hand soap will have no significant effect on the survivorship of E. coli and Staph Alternative hypothesis: The antibacterial hand soap will have a significant negative effect on the survivorship of E. coli and Staph Hypotheses

Materials Latex gloves Spreader bar Escherichia coli (DH5-alpha) Agar plates Ethanol Matches Vortex Hand soap 0.22 Micron sterile filter 64 LB Agar Plates (0.5% yeast extract, 1% tryptone, 1% sodium chloride) Escherichia coli (DH5-alpha) Staphylococcus epidermidis Micropipettes Micro tubes Sterile dilution fluid [SDF] (100mM KH2PO4, 100mM K2HPO4, 10mM MgSO4, 1mM NaCl) Bunsen burners Materials

1. E. coli and Staph. e. were grown overnight in sterile LB media. 2. Samples of the overnight culture were added to fresh media in a sterile sidearm flask. 3. The cultures were incubated until a density of 50 Klett spectrophotometer units was reached. This represents a cell density of approximately 108-109 cells/ml. 4. The cultures were diluted in sterile dilution fluid to a concentration of approximately 105 cells/ml. 5 ) 5. The hand soap was diluted with sterile dilution fluid to concentrations of 0%, 0.1%, 1%, and 10% to total 10 mL Procedure

Table of concentrations 0% 0.1% 1% 10% Sterile fluid 9.9 mL 9.89 mL 9.8 mL 8.9 mL Hand soap 0 mL 0.01 mL 0.1 mL 1 mL Microbe Total volume 10 mL Table of concentrations

1. 0.1 ml. of cell culture was then added to the test tubes, yielding a final volume of 10 ml. and a cell density of approximately 10^3 cells/ml. 2. The tubes were allowed to incubate at room temperature for 10 minutes. 3. After vortexing to evenly suspend cells, 0.1 ml. aliquots were removed from the tubes and spread on LB agar plates. 4. The plates incubated at 37°C overnight. 5. The resulting colonies were counted. Each colony is assumed to have arisen from one cell. Procedure

P- Value: 8.9 x 10^-12 Alpha: 0.05

Concentration of hand soap T-Critical: 2.88 Alpha: 0.05 Concentration of hand soap T-Value Significant? 0.1% 7.75 Significant 1% 10.45 10% 11.81 Dunnett's test (e.coli)

P-Value: 6.12 x 10^-9 Alpha: 0.05

Concentration of hand soap T-Critical: 2.88 Alpha: 0.05 Concentration of hand soap T-Value Significant? 0.1% 5.07 Significant 1% 6.97 10% 9.1 Dunnett's test (staph)

Limitaions and extensions Limitations Extensions Only two species used Plating was not synchronized perfectly Only one type of exposure Small variation in exposure time More trials could be run to get a better evaluation of the results Vary exposure time Add another species to test Agar infusion Limitaions and extensions

Conclusion Staph. E. E. Coli Null hypothesis can be rejected Alternate hypothesis can be accepted Null hypothesis can be rejected Alternate hypothesis can be accepted Conclusion

References https://en.m.wikipedia.org/wiki/Staphylococcus_epidermi dis http://healthdefine.com/medical-advice/e-coli-7-tips-so- youll-never-get-sick http://web.uconn.edu/mcbstaff/graf/Student%20presentati ons/S%20epidermidis/sepidermidis.html http://www.midlandhardware.com/158426.html References

Surviving colony results (E. Coli) 0 % 0.1% 1% 10% 142 97 52 34 178 68 40 197 102 58 53 129 89 59 54 115 95 66 42 133 88 47 185 73 49 148 60 83 61 Surviving colony results (E. Coli)

E. Coli anova P-value was 8.9 x 10^-12 Alpha was 0.05 This number is less than 0.05 so Dunnett's tests must be run Alpha was 0.05 E. Coli anova

Surviving colony results (Staph) 0 % 0.1% 1% 10% 197 109 102 96 158 165 126 172 129 119 93 163 134 128 99 193 155 143 164 137 115 104 225 106 105 95 186 167 124 110 Surviving colony results (Staph)

Staph E. anova The p-value was 6.12 x 10^-9 Alpha was 0.05 This number is less than 0.05 so Dunnett's tests must be run Alpha was 0.05 Staph E. anova