Major article
A comparison of the antibacterial efficacy and cytotoxicity to cultured human skin cells of 7 commercial hand rubs and Xgel, a new copper-based biocidal hand rub

https://doi.org/10.1016/j.ajic.2008.09.011Get rights and content

Background

Hand cleanliness is important in hospital infection control, but skin irritation from frequent alcohol-based hand rub use reduces compliance. We have compared a new copper biocide/Aloe vera-based biocidal hand rub (Xgel) with 7 commercially available hand rubs.

Methods

Hand rubs were cultured with human skin cells for 24 hours after which cytotoxicity was assessed using the sulforhodamine B assay. The EN 12054 bacterial suspension test protocol was used to assess biocidal activity of 2 of the least cytotoxic hand rubs (Xgel and Purell).

Results

Hand rubs had 50% cytotoxic concentrations ranging from >10% to <0.1% vol/vol. In the EN12054 assay, Xgel reduced colony forming units (CFU) by >108 with methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter in 1 minute, whereas Purell only reduced CFU by 104 and 105, respectively. Purell was ineffective against C difficile spores, whereas Xgel produced a 3 × 103 reduction in CFU.

Conclusion

The hand rubs had a wide range of cytotoxicity values for human skin cells, with Xgel being the least cytotoxic to human skin cells. In the EN 12054 bacterial suspension test, Xgel was more effective than Purell against all organisms tested. It should be noted that these in vitro results may not translate into clinical differences.

Section snippets

Materials

The hand rubs were provided as samples by their manufacturers. Xgel (hand rub A) is a new Aloe vera-based hand gel containing 314 ppm of the novel copper-based formulation CuAL42,6 together with xanthan gum and citric acid as thickener and stabilizer, respectively, and was provided by Remedy Research Ltd. Desisoft (hand rub B) was provided by Soft Protector Ltd, Espoo, Finland. Nexan (hand rub C) was provided by Nettuno s.r.l. viale Industria, Castelli Calepio (BG), Italy. Spirigel (hand rub D)

Cytotoxicity assay

Cytotoxicity dose-response curves for the 3 non-alcoholic hand rubs (A, B, and C) are shown in Fig 1A. Hand rub A, a non-alcoholic hand gel consisting of Aloe vera gel 314 ppm of CuAL42, a copper-based biocide as the active ingredient, reduced cell survival by 40% at the highest concentration (10% vol/vol) but was not cytotoxic at lower concentrations. Hand rub B, a handwash that contains polyhexamethylene guanidine hydrochloride (PHMG; 0.3%) as its active vingredient, had a 50% cytotoxic

Discussion

The results of the cytotoxicity assay show that the 8 hand rubs tested have a wide range of cytotoxicity to A-431 human skin cells. Three of the 4 hand gels tested (A, D, and E) had modest cytotoxic effects on A-431 cells with CC50 values of >10%, 7.5%, and 6% vol/vol, respectively, with hand rub G (CC50 = 0.7% vol/vol) being the exception. Hand rubs D and E contain only ethanol as their active ingredient, and their CC50 values were similar to that of ethanol (Table 1). Hand rub A contains a

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Remedy Research Ltd. contracted and funded this research on its proprietary and patented copper-based formulations.

Funded in part by the NIMR/UCLH/UCL Comprehensive Biomedical Research Centre (to V.A.G). The authors report no conflicts of interest.

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