Relative bactericidal efficacies of a selection of alcohol-based hand sanitizers (ABHS) available in Ghana

Abstract The liberal use of alcohol-based hand sanitizers (ABHS) for hand disinfection has raised questions regarding the bactericidal efficacies of brands that are widely available in Ghana. Ten different brands of hand sanitizers bearing different chemical constituents and originating from six different countries were purchased in Kumasi, Ghana. The 10 samples represent the only available brands in the retail market. Purchased brands were examined for their relative bactericidal efficacies with the combined use of agar well diffusion, broth dilution, and viable bacterial count reduction assays. Serially diluted solutions of the ABHS displayed variable brand-specific bactericidal efficacies against a panel of bacteria specimen that comprised three gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis, Streptococcus pneumonia) and three gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi) in the agar well diffusion and in the broth dilution assays. Neither gram-positive nor gram-negative bacteria strains showed a clear pattern of preferential susceptibility to the growth inhibitory activities of any of the examined brands of ABHS. Only HS9 displayed a full spectrum bactericidal activity against all bacteria species in agar diffusion assay. Full strength ABHS formulations demonstrated brand-based rapid bactericidal action on hands of volunteers in a pattern best described as a post-ABHS-treatment reduction in levels of viable bacteria hand counts. HS9 displayed the highest efficacy and this relative estimation held true in all the three assays utilized for the assessment of bactericidal efficacies.