Analysis of Antimicrobial Activity Using Hand Sanitizers
Keywords:Hand sanitiser, ethanol, WHO, antimicrobial activity, log reduction
Alcohol-based hand sanitiser is introduced to replace hand washing when water is unavailable to decrease the rate of infectious diseases. Proper hand hygiene is essential during pandemics to transmit pathogens through contaminated surfaces. The efficacy of hand sanitisers is reviewed based on a quantitative suspension test according to European Standards against microorganisms Staphylococcus aureus, Saccharomyces cerevisiae and Escherichia coli. Five selected products, 96% (v/v) ethanol, 65% (v/v) ethanol, World Health Organization (WHO) formulated hand rub, Commercial oil-based and non-oil-based (Brand A and Brand B, respectively), are used as treatments against the microbes. The post-treatment results of hand sanitisers as colony-forming units on tryptone soya agar plates are counted. The inoculation of microbes using the spread plate technique can identify CFU units where the logarithmic reduction factor is determined. The minimum requirement of the log reduction factor is 2 logs to provide sufficient bactericidal activity. Based on the results, Brand A and B, 96% (v/v) and WHO-formulated products achieve the minimum standards with high efficacy against the test organisms. However, 65% ethanol (v/v) is less effective. The minimum amount of hand sanitiser doses is 3 mL of complete coverage on hand to ensure high inhibition percentages of microbes. Moreover, the WHO recommended that the application time requirement is 60 seconds.