Objective: The study was designed to compare the efficacies of bland soap handwash and isopropyl alcohol hand rinse in preventing transfer of aerobic gram-negative bacilli to urinary catheters via transient hand colonization acquired from direct patient contact. Glove juice recovery of gram-negative bacteria was considered transient colonization; catheter recovery was considered transfer colonization.
Design: The contact source for gram-negative bacteria was a single "high burden" groin skin carrier (greater than or equal to 10(4)/ml cup scrub fluid). Using a two-period cross-over design, 6 healthcare workers had 2 15-second contacts for each hand followed by either soap handwash or alcohol hand rinse (12 experiments with each treatment). Between 4 to 5 minutes after contact, each hand manipulated a catheter; the catheter was then cultured and the hand was glove juice tested.
Results: Soap handwash failed to prevent gram-negative bacteria transfer to the catheter in 11 of 12 (92%) experiments; alcohol hand rinse in 2 of 12 (17%) (p less than .001). Soap handwash failed to prevent transient colonization in 12 of 12 (100%) experiments; alcohol in 5 of 12 (42%) (risk ratio 2.4, 95% confidence interval 1.2-4.7). Single gram-negative bacteria species carried at source levels greater than or equal to 5.5 x 10(3)/ml (heavy contamination) established transient colonization in 23 of 30 (77%) exposures following soap handwash; single gram-negative bacteria species carried at levels less than or equal to 3.5 x 10(3)/ml established colonization in 1 of 22 (5%) similar exposures (p less than .001).
Conclusions: Bland soap handwash was generally ineffective in preventing hand transfer of gram-negative bacteria to catheters following brief contact with a heavy-contamination patient source; alcohol hand rinse was generally effective.