Efficacy of hand disinfectants against vancomycin-resistant enterococci in vitro

Abstract

Vancomycin-resistant enterococci (VRE) may be spread within a hospital via the contaminated hands of the healthcare worker. Effective hand disinfectants are necessary to break chains of transmission. We determined the bactericidal activity of 1-propanol, chlorhexidine digluconate (0·5 and 4%). Sterillium ® (45% 2-propanol, 30% 1-propanol and 0·2% mecetronium etilsulphate), Skinsept F® (70% 2-propanol, 0·5% chlorhexidine digluconate and 0·45% hygrogen peroxide) and Hibisol® (70% 2-propanol and 0·5% chlorhexidine gluconate) against 11 clonally distinct enterococcal isolates in a quantitative suspension test. Four isolates were vancomycin susceptible, four were van A and the remainder van B positive. Eight isolates were identified asEnterococcus faecium , two as Enterococcus faecalis and one as Enterococcus gallinarum . The investigator was blinded to the species and the genotype. Four parallel experiments were carried out for each isolate, each preparation, each dilution and each reaction time. 1-Propanol (60%), Sterillium, Skinsept F and Hibisol were all highly bactericidal after 15 and 30 s against VRE and vancomycin-susceptible enterococci (VSE) with reduction factors (RF) > 6·4, even in dilution of 50% (v/v). No significant difference was observed between van A isolates,van B isolates and VSE. Chlorhexidine digluconate (0.5% and 4%) was found to be less bactericidal after 30, 60 and 300 sec (RF ≤ 2·5). The van B genotype isolates were found to be significantly more susceptible to chlorhexidine (0·5%) than the van A isolates (60 sec; one-way ANOVA model;P = 0·05). After 300 sec the van B genotype isolates were found to be significantly more susceptible to chlorhexidine (0·5%) than the other two genotype isolates (P = 0·016). The van A isolates were found to be significantly more suscpetible to chlorhexidine (4%) than the van B isolates (300 s;P = 0·024). E. faecium was found to be less susceptible to chlorhexidine than E. faecalis at all concentrations and reaction times, but significant differences between RF were only observed at 60 sec for both chlorhexidine concentrations (P< 0·05;t -test for independent samples). Propanol is much more effective against enterococci than chlorhexidine and combination of the two may be useful in providing an immediate and long lasting effect.