YOUR SHOWERHEAD'S SLIME IS ALIVE.

Every time you hop in the shower, you are in the company of millions of microorganisms, most of which probably will not hurt you. However, researchers from the Cooperative Institute for Research in Environmental Sciences--CIRES is a partnership of the National Oceanic and Atmospheric Administration, Silver Spring, Md., and the University of Colorado, Boulder--have identified mycobacterium as the most-abundant genus of bacteria growing in the slimy "biofilm" that lines the inside of showerheads. Some of those bacteria can cause lung disease in the immunocompromised.

CIRES researcher Matt Gebert and his colleagues analyzed DNA extracted from slime samples...