I saw this Associated Press article in our morning's newspaper:

A study says showerheads can harbor tiny bacteria that come spraying into your face when you wash. People with normal immune systems have little to fear, but these microbes could be a concern for folks with cystic fibrosis or AIDS, people who are undergoing cancer treatment or those who have had a recent organ transplant.

Researchers at the University of Colorado tested 45 showers in 5 states as part of a larger study. They were reporting their shower findings in today's edition of the Proceedings of the National Academy of Sciences.

The researchers offer suggestions for the wary, such as getting all-metal showerheads, which microbes have a harder time clinging to. Still, showerheads are full of nooks and crannies, making them hard to clean, the researchers note, and the microbes come back even after treatment with bleach. People who have filtered showerheads could replace the filter weekly, added co-author Laura K. Baumgartner. And, she said, baths don't spray microbes into the air as much as showers, which blast them into easily inhaled aerosol form.

The bugs in question are Mycobacterium avium, which have been linked to lung disease in some people. Symptoms of infection can include tiredness, a persistent, dry cough, shortness of breath, weakness, and "generally feeling bad."