1IBDP Grade 12, Shiv Nadar School, Pahari Road, Block E, DLF Phase 1, Sector 26A,
Gurugram, Haryana 122011
2Department of Microbiology, Rajiv Gandhi Cancer Institute and Research Centre,
New Delhi-110085, India.
3Department of Uro-oncology, Rajiv Gandhi Cancer Institute and Research Centre,
New Delhi-110085, India
Ind.J.Applied.Microbiol. 2021 .23(2) : 11-29
The world health organization (WHO) in 2009 in their consensus recommendation on
hand hygiene has suggested two formulations of hand sanitizers which are also the basis of main
components of most commercial and medical grade hand sanitizers today. We evaluated the in vitro
antimicrobial efficacy of ten different hand sanitizers (seven commercial including herbal (sanitizer
1, 2, 3, 4, 5, 9, and 10) and three of medical grade (sanitizers 6, 7 and 8). Method: The efficacy of
hand sanitizers was checked against five ATCC strains: Staphylococcus aureus, Staphylococcus
hemolyticus, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecalis. Experiment
was performed in three parts. The first part was performed in triplicate to see the zone of inhibition
for each sanitizer. The second part was performed to see the duration of action of each hand
sanitizer and third part (in triplicates) was performed to see the efficacy of active components
individually (alcohol and disinfectant in different dilutions). Results: Sanitizers with ethanol and
chlorhexidine as main ingredients (6 and 8) showed zone of inhibition for all tested gram positive
and negative bacteria. Sanitizer 7 (propanol and mecetronium ethyl sulphate as main components)
showed zone of inhibition for all tested bacteria except Pseudomonas aeruginosa. Other hand
sanitizers did not show any zone of inhibition after incubation for 24 hours at 37oC. For second part
hand sanitizer 6inhibited growth for all bacteria at all-time points (15, 30, 45 &60 seconds) and Sanitizer 8(ethanol and chlorhexidine as main components) showed growth inhibition only after
15seconds. Other hand sanitizers did not show any growth inhibition. For the third part, all
dilutions of ethanol and propanol (60%, 70% and 80%) were unable to inhibit growth of any ATCC
strain. Disinfectant 2.5v/v chlorhexidine was able to inhibit all five bacteria.0.2 gm mecetronium
ethyl sulphate showed inhibition for all except Pseudomonas aeruginosa. Conclusion: Hand
sanitizers with alcohol only as their main ingredient were unable to inhibit growth of ATCC strains.
Hand sanitizers with both alcohol and disinfectant performed better .These findings preludes for
further in vivo studies to validate 2009-WHO hand sanitizer preparations and suggest
modifications.
Keywords: Hand Sanitizer, WHO, alcohol, ethanol, chlorhexidine, mecetronium ethyl sulphate
