Improvement of the Efficacy an WHO Alcohol-based Hand Rub Formulation by Reducing Isopropanol Content and Associating Syzygium aromarticum and Piper nigrum Essential Oils

Aim: This work was carried out in order to reduce the isopropanol contain of a World Health Organization (WHO) basic alcohol based hand rub (ABHR) formulation by substituting part of it with ethanol and essential oils.

Study Design: A quasi-experimental design was used, based on WHO basic formulation modification, antimicrobial assessment followed by a panel test and challenge test of the best formulation.

Place and Duration of the Study: The study was carried out in different laboratory of the University of Yaoundé 1 during March 2017 to July 2018.

Methodology: This study was performed by producing different formulations nested from the WHO basic formulation and testing their antimicrobial capacity on selected strains based on the microbial percentage reduction. Following this, the best formulation was compared to two commercial products trough a panel test and later challenged with selected organism (Staphylococcus aureus SR196, Salmonella Typhi 15SA, Escherichia coli ATTC25922 and Pseudomonas aeruginosa PA01) inoculated in the product after different storage periods for one year and the antimicrobial stability assessed on the same strain for the same length of conservation.

Results: The partial substitution of isopropanol with ethanol and Piper nigrum and Syzygium aromaticum essential oils proved to possess more antimicrobial properties than the original WHO formulation. The best formulation caused a 6 Log cells/ml reduction of the initial population compared to the 4 Log cells/ml of the WHO formulation. The product also proved to maintain its activity for one year and to be able to deactivate possible contaminations by Salmonella Typhi 15SA, Staphylococcus aureus NCTC10652, Escherichia coli ATCC25922, Pseudomonas aeruginosa PA01.

Conclusion: The present work is a contribution to the improvement of ABHRs and could permit the reduction of hand hygiene associated infections in industries and health care facilities.