Bacteria and spore recovery from bathroom hand dryer air or environmental aira

LocationNo. and types of bathroomsEnvironmentbHand dryersc
Total no. of colonies/plateNo. of KSF/plateTotal no. of colonies/platedNo. of KSF/platee% KSFf
Building 17 M, 7 W0.21 ± 0.57017.7 ± 10.10.68 ± 0.933.85
Building 27 M, 7W0023.8 ± 23.31.16 ± 1.074.87
Academic building4 M, 4 W1 ± 1.46059.5 ± 60.21.5 ± 1.42.52
  • a Plates were exposed to the bathroom environment for 2 min or for 30 s under hand dryers in men's (M) or women's (W) bathrooms on various floors in research buildings 1 and 2 and on research floors above the academic building, and total bacteria and levels of Kmr sporeformers (KSF) were quantified, all as described in Materials and Methods. Values for total colony number and number of Kmr sporeformers are averages ± standard deviations.

  • b The range of numbers of colonies per individual open plate exposed to the bathroom environment for 2 min was 0 to 3. Exposure of two open plates to bathroom environmental air for 18 h in two bathrooms yielded 2, 4, 8, and 10 colonies (average, 6 ± 3.65).

  • c The range of total colonies per individual plate exposed to a bathroom hand dryer air for 30 s was 3 to 254.

  • d The plates exposed to bathroom hand dryer air in research areas above the academic building had significantly higher numbers of total colonies than the those in research building 1 (P < 0.001) and research building 2 (P < 0.001). There was no statistical difference between the numbers of colonies recovered from bathrooms in research building 1 and those from building 2 (P = 0.235).

  • e Hand dryer air in research building 2 bathrooms had significantly fewer Kmr sporeformers than either bathrooms in research building 1 (P = 0.025) or bathrooms in the research area above the academic building (P = 0.016). There was no difference in numbers of Kmr sporeformer recovered from bathrooms in building 1 and those for the research areas above the academic building (P = 0.440).

  • f There was also a statistically significant difference in the percentages of Kmr sporeformers recovered from hand dryer air in bathrooms in buildings 1 and 2 (P = 0.044) and the percentages in building 1 and above the academic building (P < 0.001), but not for the percentages for building 2 and above the academic building (P = 0.306).