Efficacy of an automated ultraviolet C device in a shared hospital bathroom
Toilet flushing generates airborne particles that contain bacteria and viruses.
The UVC-treated BR (geometric mean [GM] = 153.2 colony forming units [CFU]/m3, geometric SD [GSD] = 1.7) had a 35.2% re- duction in aerobic bacterial bioaerosol concentration compared with the control BR (GM = 236.5 CFU/m3, GSD = 1.44) (Fig 1). This differ- ence was even more pronounced for anaerobic bacterial bioaerosols, where the UVC-treated BR (GM = 45 CFU/m3, GSD = 2.4) had a 47.7% reduction compared with the control BR (GM = 86 CFU/m3, GSD = 2.8).
The mean bacterial concentration on the UVC-treated BR counter (GM = 1.6 CFU/[10 cm]2, GSD = 2.2) was reduced by approximately 95% compared with the control BR counter (GM = 31.0 CFU/10 cm2, GSD = 3.1) (Fig 2). The greatest effect was seen for surface seat bac- teria, with a 97% reduction in the UVC-treated BR (GM = 7.7 CFU/ [10 cm]2, GSD = 5.5) compared with the control BR (GM = 224 CFU/ [10 cm]2, GSD = 7.5). Two outliers collected from the toilet seat of the control BR had concentrations >2,000 CFU/(10 cm)2 (not shown in Fig 2). These outlier samples may represent highly contami- nated droplets deposited onto the seat after flushing.
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