The collection times were 1.5 and 3 h. In addition, samples were
taken from facial masks of personnel and from surfaces in the rooms before
and after disinfection. After 48 h of incubation at 37 C, colonies were
counted and classified by Gram stain. The results showed significant contamination
of the room at all distances sampled when high-speed instruments
were used (mean 970 colony-forming units/m2/h). The bacterial
density was found to be higher in the more remote sampling points.