1. The effect of different disinfectants on sterilizing the bacterial concentration of Staphylococcus epidermidis on computer keyboards Arlen Chen Spring Valley High School 120 Sparkleberry Lane Columbia, SC, 29229 1/19/06

2. Introduction o Recently, it has been discovered that potentially harmful bacteria can survive on computer keyboards and keyboard covers. o Some of the bacteria tested in the studies can cause complicated abdominal infections, pneumonia, and different skin infections. o Therefore, the disinfection of these bacteria from computer keyboards must be considered.

3. Introduction o Staphylococcus epidermidis oGram-positive, immobile, grape-like clusters oFacultative anaerobe o Ecology / Pathology oSmall, white colonies oInhabits skin of healthy humans oOnly infects immunocompromised humans oResistant to antibiotics, antibodies, phagocytosis http://www.bact.wisc.edu/Bact330/nfS.epidermidis.jpeg

4. Introduction o Staphylococcus epidermidis oInhabits skin o Infections oSkin lesions oPneumonia oMeningitis oUrinary tract infections

5. Introduction o Independent Variables oClorox oLysol oFormula 409 oDisinfectant Keywipes o Dependent Variable oStaphylococcus epidermidis colonies left after disinfection

6. Previous Research o Even though previous research was conducted on the survival of bacteria on keyboards, there has not been any research conducted on determining which disinfectant is best to sterilize the bacteria. o Therefore, the purpose of this study was to determine the ability of four disinfectants to sterilize Staphylococcus epidermidis on computer keyboards.

7. Hypothesis o Using Clorox for 10 minutes will be the most effective way of sterilizing the bacteria. o Based on the fact that Clorox contains Clorox and the halogen chlorine.

8. Materials Staphylococcus epidermidis Nutrient Agar Nutrient Broth Beakers Petri Dishes Keyboard Keys Lysol Clorox Formula 409 Disinfectant Keywipes Incubator Autoclave Sterile Cotton Swabs Sterile Disposable Inoculating Loops Hot Plate

9. Experimental Design Diagram No Disinfectant LysolCloroxFormula 409 Disinfectant Keywipes 4 Trials 5 Trials DV: Growth of bacteria C: Time incubated Time disinfectant is applied Time bacterium is applied Bacterium used on keyboards

10. Methods o Creation of nutrient agar and broth. o Staphylococcus epidermidis was transferred into the nutrient broth o Broth was spread onto each key.

11. Methods o Each disinfectant was sprayed or wiped on the five keys o Sterile cotton swabs used to swab the surface of the key and streaked onto the corresponding agar plate. o Once the streaking was completed, the agar plates were placed into the incubator at 31ºC for 24 hours.

12. Results

14. xControlLysolCloroxFormula 409Disinfectant Keywipes Trial 1002314 Trial 2431051 Trial 30 2 022(1)44 Trial 419312258 Trial 5539 Mean: 15.50 1.50 0.75 21 25.2 StdDev: 20.40 1.29 0.96 20.04 24.51

15. Results ANOVA Summary Table x d.f. Sum of Squares Mean SquareFp Disinfectants4 2207 5521.78.179 Error18 5266 310--- Total22 7472 ----------- Using the F-distribution table at a significance level of.05, the critical value (C.V.) is found to be 2.93.

16. Discussion o When examining the number of colonies for each disinfectant, it was found that there was no significant difference between the mean number of colonies at α=0.05. o Therefore, the experimental hypothesis was rejected; the disinfectants did not vary in their abilities to disinfect Staphylococcus epidermidis on computer keyboards.

17. Sources of Error o Counting errors o Outliers in the data o Errors in data analysis. o Small sample size

18. Future Research o Different bacteria o Have a larger sample size o Other surfaces o Other disinfectants

19. Acknowledgements o I would like to thank Mr. Soblo for providing guidance, motivation, ideas, and advice throughout my research project, as well as allowing me to use his class as my lab. o I would like to thank Ms. McAlpine for assisting me in ordering materials. o I would like to thank Ms. Sutton for providing me with information and advice. o I would also like to thank my family for their support and guidance throughout my project.

20. Literature Cited o Adams, D. (2005). Keyboards latest culprit in hospital infections. AMNews. Retrieved May 2, 2005 from http://www.ama- assn.org/amednews/2005/05/02/prl20502.htm o Bates, B. (2005). Computer keyboards act as bacteria reservoir. Family Practice News 35, 27. Retrieved August 6, 2005, from Health and Wellness Resource Center. o Hannford, A. (2003 May 19). Key strokes; Mmmmmm; bacteria: eating at your desk and swapping work stations can seriously damage your health, discovers an anxious Alex Hannaford. The Evening Standard (London, England). Retrieved May 2, 2005, from Custom Newspapers (Infotrac-Gale). o Leichman, A. (2005 January 11). Average office is breeding ground for germs. Knight Ridder/Tribune Business News Retrieved May 2, 2005, from Custom Newspapers (Infotrac-Gale). o Marquis, R. (2005). In Microsoft Encarta. Retrieved August 6, 2005, from http://encarta.msn.com/encyclopedia_761574409/Bacteria.html o WebMDHealth. (2005). What’s lurking on your computer? Bacteria can quietly thrive on computer keyboards. Retrieved May 1, 2005, from http://my.webmd.com/content/Article/104/107365.htm?pagenum ber=1

21. The effect of different disinfectants on sterilizing the bacterial concentration of Staphylococcus epidermidis on computer keyboards Arlen Chen Spring Valley High School 120 Sparkleberry Lane Columbia, SC, 29229 1/19/06