A hidden reservoir of transfer organisms are those growing on the skin underneath sterile gloves. Hand washing with soap and water or a medicated soap must include thorough drying of the hands prior to donning gloves. Gloves worn for too long a period of time can release organisms from the moist environment when changed or removed, especially if only bar soap is used.
The World Health Organization in a worldwide literature review has ranked the de-germing ability of hand washing agents in decreasing order of effectiveness:
1) alcoholic hand sanitizer (60 to 70%) solution, foam, or gel,
2) medicated soap (solid or liquid),
3) soap and water, with specified wash times of 20 to 30 and 40 to 60 seconds for alcohol and soap and water respectively.
From a formulation and regulatory point of view, solid or liquid soaps are compositions of long chain fatty acids or anionic detergents and water. They are regulated for safety only (acute toxicity) by the Consumer Product Safety Commission (CPSA). When an antimicrobial is added (e.g. Triclosan) the soap becomes a drug and is regulated for both safety and efficacy by the FDA, albeit with rather loose labeling requirements.
From: Hand Hygiene In Controlled Environments