Evaluation of antimicrobial efficacy of different hand sanitizers available in Thimphu, Bhutan

Introduction: Hand washing and the use of alcohol based hand-rub are two effective hand-hygiene procedures. Though the compliance to hand washing was relatively low, the COVID-19 pandemic situation has drastically increased the use of hand sanitizers. Thus, many hand sanitizer brands have entered the market and this study was taken up to assess the microbial efficacy of different types of hand sanitizers available in Thimphu. Methods: Ten gel based and ten liquid hand sanitizers were collected from various retail pharmacy shops in Thimphu during first quarter of 2020. Laboratory based experiment was performed using standard organism; Gram Negative Bacteria (GNB) Escherichia coli (American Type Culture Collection 25922) and Pseudomonas aurigenosa (American Type Culture Collection 27853), Gram Positive Bacteria (GPB) Staphylococcus aureus (American Type Culture Collection 25923) and a cocktail of GNB and GPC. The efficacy of hand sanitizer was assessed with the size of the Zone of Inhibition (ZoI). Results: The hand sanitizers were found to be effective against all strains of micro organism but with differentsize of ZoI. The maximum size of Zone of Inhibition was observed by sample N and Q (ZoI diameter 33.0±0.14mm) for American Type Culture Collection 25923. The Zone of Inhibition of liquid base hand sanitizers was significantly higher than that of gel base (p<0.05). Conclusions: The study presents that liquid base alcohol based hand sanitizer is more efficient than the gel form.