Background: The difference between use of a scrub brush versus soap alone in reducing hand bacterial counts has never been established by a prospective, comparative study.
Methods: Fifteen volunteers were taught the 5-minute surgical scrub. Baseline specimens were obtained by the glove fluid sampling procedure. Subjects were randomized to (1) scrub with an inert scrub brush and 4% chlorhexidine soap with isopropyl alcohol or (2) wash with 4% chlorhexidine soap with isopropyl alcohol alone. Specimens were obtained immediately after the scrub was completed and 45 minutes later. The experiment was repeated by use of a cross-over design after a 1-week washout period. The data were analyzed by three methods that took into account the broad range of baseline hand counts (5 x 10(1) to 11.2 x 10(4): method 1, the discordance between presence/absence of hand bacterial counts within individuals at 45 minutes for soap versus soap and brush; method 2, the absolute reduction of bacteria (baseline vs 45 min.) for soap versus soap and brush; and method 3, the proportional change in bacterial counts at 45 minutes from baseline for soap versus soap and brush.
Results: Although there was no statistically significant difference for any method, the point estimates for the odds ratio (OR) showed that up to twice the number of subjects had a greater reduction in bacterial counts when they washed with soap than when they scrubbed with a brush, as evidenced by the following data: method 1, OR 2.3 (95% confidence interval [CI] 0.53, 13.99) for soap alone; method 2, OR 1.0 (CI 0.23, 4.35); and method 3, OR 2.0 (CI 0.54, 9.10) for soap alone.
Conclusions: The effect of use of soap alone in reducing hand bacterial counts at 45 minutes was similar to use of soap and brush. Soap can be used alone and the surgical infection rate prospectively monitored.