Biologist Daniel Smith crouched in an empty patient room at the new University of Chicago hospital and dragged a white cotton swab across the gleaming tile.
Smith studied the dust-smudged tip before breaking it off into a plastic tube labeled "floor."
"A good sample for us," said Smith, securing the tiny vial in a box chilled by dry ice. "Although you can't see them, there are literally billions of (bacteria) cells on these surfaces."
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