Fig 4. Bacterial colony numbers in cultured skin swab suspension.

The mean number and standard deviation of colonies formed pre-irradiation, 5 minutes after irradiation, and 30 minutes after irradiation were 7.21±7.48, 0.05±0.23, and 0.79±2.53, respectively. Each data is shown as a black spot, and individual pair of data are connected with lines. The colony number was significantly decreased by 222-nm UVC irradiation at 5 and 30 minutes after the irradiation than at the pre-irradiation. No significant difference was observed in the colony number between 5- and 30-minute post-irradiation skin swab cultures. Abbreviation: UVC, ultraviolet radiation C.