New research suggests that many shower heads are teeming with Mycobacterium avium, a bacteria that can cause lung disease. The University of Colorado scientists report that a third of the 50 shower heads they checked contained a film coating of "significant levels" of the bacteria inside. "If you are getting a face full of water when you first turn your shower on, that means you are probably getting a particularly high load of Mycobacterium avium, which may not be too healthy," said lead researcher Norman Pace. (But how many people are facing the shower head when they turn on the water?) Anyway, from the BBC News:
Water spurting from shower heads can distribute bacteria-filled droplets that suspend themselves in the air and can easily be inhaled into the deepest parts of the lungs, say the scientists from the University of Colorado at Boulder…
While it is rarely a problem for most healthy people, those with weakened immune systems, like the elderly, pregnant women or those who are fighting off other diseases, can be susceptible to infection…
Since plastic shower heads appear to "load up" with more bacteria-rich biofilms, metal shower heads may be a good alternative, said Professor Pace.
Taking showers 'can make you ill' (BBC News)
"Opportunistic pathogens enriched in showerhead biofilms" (PNAS)