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Determining the effectiveness of alcohol-based sanitizer concentrations on strains of epidermal floras
  • Ananya Gupta
Ananya Gupta
Notre Dame San Jose

Corresponding Author:agupta24@ndsj.org

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Purell kills 99.99% of the most common germs which cause illnesses. This means that 0.01% of bacteria still remains on the skin surfaces of the organism. Optimal bactericidal efficacy is at 60-90% concentration as even pure alcohol is less bactericidal. Purell consists of ethanol which proves to be most effective in virucidal activity. Adding aqueous solution to ethanol solutions can increase its efficacy against viruses that are more resistant to ethanol alone. However, it is well known that hand sanitizers are ineffective against non-developed viruses. Alcohol-based hand sanitizers are very effective for quickly destroying many pathogens through aqueous alcohol solutions. This study tests the effectiveness of alcohol-based sanitizer concentrations on specific types of epidermal bacteria. This experiments alcohol-based sanitizer concentrations on two types of epidermal floras, Staphylococcus epidermidis and Escherichia coli B. To test this hypothesis, a two-part procedure was conducted using the Kirby-Bauer method. Low, high, and optimal concentration solutions are formulated as the experimental group while the control group is a pure aqueous solution. Using sterile technique, cultures of Staphylococcus epidermidis and Escherichia coli B were dispensed onto Petri dishes and tested with each different concentration type. The results of Escherichia coli B disproved the hypothesis as high concentration levels were most effective in regulating its presence while Staphylococcus epidermis modulated best under optimal concentrations. This considers the effectiveness of sanitizer on bacteria that remains on the epidermis even after Purell is applied and can display how concentration modifications affect the growth of bacteria.