Germi-X herbal-based spray disinfects smartphone surfaces: implication on fomite-mediated infection spread

Abstract

Inanimate objects/surfaces become fomites upon contacting infectious agents such as disease-causing bacteria, fungi and viruses. Smartphones are one of the most prominent among these fomites. COVID-19 pandemic has raised the awareness on mobile sanitization, as an active measure to curb fomite-mediated viral transmission. Available mobile sanitizers and ultraviolet (UV) ray mediated mobile sanitization have their own sets of pros and cons, often being less user-friendly. This study explored the germicidal efficacy of an herbal-based sanitizer, Germi-X spray, on hands and mobiles, through microbiological techniques of micro-broth dilution and Kirby-Bauer disc diffusion assay, thumb print assay and swab test. Notably, Germi-X spray was found to be 6-67% more effective against surface pathogens, like, Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas fluorescens and Pseudomonas aeruginosa, as compared to a very popular product in the Indian market, which was taken as a control for this study. The observed anti-bacterial activity of the spray from disc-diffusion assay suggests its greater surface retentivity as compared to the control. Germicidal potency of Germi-X spray, when used to sanitize hands, was found to be greater than 80%. There was ~ 17-fold reduction in microbial counts after sanitizing smartphones with Germi-X spray. The novelty of this study lies in providing experimental evidence for this herbal-based surface sanitizer in efficiently disinfecting one of the super contaminated fomite, the smartphones. In conclusion, having an herbal base with a high germicidal efficacy against surface pathogens, together with longer surface retention, Germi-X spray appears to be an eco-friendly and cost-effective sanitizer for the surfaces of electronic gadgets like smartphones.

Keywords: Fomite-based infection; Germicidal; Hand and mobile sanitizer; Herbal-based spray; Surface contamination.

Fig. 1

Kirby Bauer disc diffusion assay showing anti-bacterial activity and prolonged surface retention of Germi-X spray. a–d Prolonged surface retention of Germi-X spray is depicted with representative digital images of S. epidermidis (a), S. aureus (b), P. fluorescens (c) and P. aeruginosa (d) showing the zones of inhibition (demarcated with black broken circles) around the discs soaked with Germi-X spray. Discs soaked in standard germicidal spray did not form any such bacterial growth free surrounding zones

Fig. 2

Germicidal effect of Germi-X spray on different surface pathogenic bacteria. a–d Grouped column graphs representing comparisons between % bacterial growth inhibition exhibited by Germi-X spray and standard germicidal spray against S. epidermidis (a), S. aureus (b), P. fluorescens (c) and P. aeruginosa (d). The red broken lines are used to indicate 99% of the respective bacterial growth and blue open oblongs are used to mark the concentrations of Germi-X spray and standard at which 99% inhibition of respective bacterial growth was achieved

Fig. 3

Germicidal potency of Germi-X spray. a–d Dose–response curves showing dose-dependent inhibitory effect of Germi-X spray and standard on the growth of S. epidermidis (a), S. aureus (b), P. fluorescens (c) and P. aeruginosa (d) Concentrations responsible for 30 (IC₃₀), 50 (IC₅₀), 70 (IC₇₀) and 90 (IC₉₀) % growth inhibitions, as determined through non-linear regression analysis, are mentioned

Fig. 4

Sanitizing efficacy of Germi-X spray. a, b Representative digital images of bacteriological plates with thumb prints from the same volunteer without (a) and with sanitization (b) with Germi-X spray. c Sanitization efficacy of Germi-X spray is represented as % germicidal potency bar graph. Statistical significance was determined through Student’s t-test and observation represented as ***p < 0.001 for the difference between sanitization without and with Germi-X spray

Fig. 5

Effectivity of Germi-X spray as a smartphone sanitizer. a Pictorial depiction of acquisition of germs on inanimate surfaces thereby forming fomites and their subsequent role in transmitting diseases. The illustration also summarizes the experimental steps followed for collecting swab samples from smartphones before and after sanitization with Germi-X spray. b, c Representative digital images of bacteriological plates showing the growth of microflora in the swab sample collected from smartphones before sanitization with Germi-X spray (b) and its lack thereof after sanitization (c). d Paired line graphs depicting the reduction in germ load after sanitization of smartphones with Germi-X spray. The statistical significance between the average CFUs in the two groups is determined through Students’s t-test and indicated as ***p < 0.001