Bacterial population kinetics on hands during 2 consecutive surgical hand disinfection procedures

Although consecutive surgical hand disinfections is common clinical practice, the effect on the bacterial density on hands has not been studied for all commonly used hand rubs. We studied the effect of 2 consecutive applications of hand rubs on resident bacterial hand flora.

A propanol-based hand rub (PBHR; Sterillium) and the reference alcohol (60% n-propanol) were tested in a Latin-square design according to EN 12791. The first application of the PBHR was always for 1.5 minutes; the second application was for 1.5, 1, or 0.5 minutes. The reference alcohol was always applied for 3 minutes. Pre-values and post-values were obtained in accordance with EN 12791.

The first reference disinfection reduced the bacterial density by 2.87 log(10) (immediate efficacy) and 2.27 log(10) (after 3 hours). The PBHR yielded a similar reduction. Immediately after the second reference disinfection, bacterial density was reduced by 0.45 log(10). Application of the PBHR yielded greater reductions of 0.71 log(10) (after 0.5 minute), 0.79 log(10) (after 1 minute), and 1.12 log(10) (after 1.5 minutes). The difference between all treatments was not significant (P = .089; Friedman test). After 3 hours, bacterial density was further decreased by 1.11 log(10) (reference disinfection), 1.89 log(10) (PBHR, 1 minute), 1.67 log(10) (PBHR, 1.5 minutes), and 1.08 log(10) (PBHR, 0.5 minute). The difference between all treatments was significant (P = .005), but none of the short treatments with the PBHR was significantly less effective than the reference treatment (P > .05; Wilcoxon-Wilcox test).

Overall, a simple 1.5-minute application of a well-formulated PBHR for surgical hand disinfection keeps the bacterial density as low as possible ("irreducible minimum") even in 2 consecutive surgical procedures of 3 hours.