Subungual bacteria of the hand: contribution to the glove juice test; efficacy of antimicrobial detergents.

Methodologies for evaluating the efficacy of antimicrobial agents in the bacterial flora of the hand involve variations of the "glove juice" or "sterile bag" procedures. In this study we demonstrate that the subungual flora contribute significantly to the recovery of bacteria in these procedures. Culturing hands that had the subungual spaces sealed with acrylic polish demonstrated a decay type of curve for the number of bacteria recovered in successive samplings with 10(6) colony forming units (CFU) bacteria recovered in the first sampling and 10(3) in the sixth while the opposite hand on which the subungual spaces were not sealed demonstrated a continuous recovery of 10(6) CFU. Serial scrubbings of three minutes with plain detergent, 10% povidone-iodine or 4% chlorhexidine demonstrated a three logarithm reduction for povidone-iodine and four logarithm reduction compared to plain detergent alone for chlorhexidine in hands that had subungual spaces sealed, while the opposite hand showed only a 0.5 to 1.0 logarithm reduction. Povidone-iodine produced a 0.6 logarithm reduction and 4% chlorhexidine or 1.4 logarithm reduction in the density of subungual bacteria.