Application of a gloved-hand model for multiparameter measurements of skin-degerming activity.

The application of an established gloved-hand model to multiparameter measurements of skin-degerming activity is described. In particular, appropriate experimental designs are illustrated which allow characterization of performance of topical skin-cleansing preparations in terms of rapid, sustained, cummulative, and persistent skin-degerming effects on the hand. Single-contact studies were used to define the degerming activity profiles of selected commercial surgical scrub preparations, and to establish the optimal post-treatment sampling interval for individual preparations. Rapid and sustained skin-degerming effects were measured and contrasted. Rapid skin-degerming activity, iodophor preparation. Sustained skin-degerming activity, namely, that occurring on the gloved hand during a postcontact interval, was shown and characterized for two hexachlorophene preparations. Multiple-contact studies with a 3% hexachlorophene preparations were used to illustrate cummulative and persistent skin-degerming effects. Cummulative skin-degerming activity was demonstrated in terms of progressive bacterial reductions after repeated contacts within a single day. Presistent skin-degerming activity was shown in terms of the profile of daily pretreatment bacterial counts after multiple contacts over successive days. Uniformity of treatment response was established for a broad range of pretreatment bacterial counts extending from approximatley log 4 to log 7 per hand. The importance of pretreatment bacterial count measurement and of adequate neutralization of hand extract samples is stressed. A randomized-hand experimental design is discussed relative to its versatility and amenability to statistical analysis.