Hand-washing degerming: a comparison of povidone-iodine and chlorhexidine

Two antiseptic preparations for hand washing were compared by the glove-juice method in a crossover study on 10 volunteers. The reference preparation was 7.5% povidone-iodine (Betadine Surgical Scrub); the test agent was 4% chlorhexidine gluconate combined with 4% isopropyl alcohol (Hibiclens). The experimental model included inoculation of the hands with a mixture of Serratia marcescens, Escherichia coli, Providentia stuartii, and Pseudomonas aeruginosa. The reference preparation achieved a reduction ratio in colony counts of 695 to 1 under the conditions of this study. The average postwash colony count after use of 7.5% povidone-iodine was significantly less than the preinoculation colony count. Logarithmic values, and the paired t test applied to them, showed a highly significant difference (p = less than 0.001) in favor of the degerming ability of the reference agent compared to the test agent. These data are of value in the selection of preparations for hand washing and may point the way to quantitative methods for other degerming studies.