Figure 1.

Microbes of the skin. Agar plates were inoculated with participants' thumb i) before washing it, ii) after washing it with antibiotic soap and warm water for 30 seconds, and iii) after rubbing with an alcohol swab. A) A plate where alcohol was used efficiently. B) Box plots showing microbial abundance computed as a categorical score (3:>300 colonies, 2:50–300 colonies, 1:<50 colonies). Abundance did not significantly differ after washing with soap (p = 0.13), and was reduced by alcohol rubbing following hand washing (p = 0.03). C) Microbial diversity expressed as the number of visually differing colonies. Diversity did not significantly differ after washing with soap (p = 0.16), and was reduced by alcohol rubbing following hand washing (p = 0.02).