Dangerous bacteria may lurk in shower heads

If your morning shower doesn't wake you up, this sure might: Dangerous bacteria may be spraying out of your shower head and right into your face, according to a new study.

Healthy people probably don't need to panic. But the opportunistic microbes, which thrive in the dark and wet environment of a shower head, might cause problems for some. If you're pregnant, a substance abuser or otherwise immune-compromised with cystic fibrosis, cancer, AIDS or a recent organ transplant, you may be at risk, the researchers said in the findings published in this month's Proceedings of the National Academy of Sciences.

The main culprit is an organism called Mycobacterium avium, a relative of the bacteria that causes tuberculosis. M. avium infections are increasingly common, perhaps because we take more showers than baths. Unlike baths, shower heads spray tiny, aerosolized particles that can be inhaled into the lungs.

The research team from the University of Colorado, which previously warned us that M. avium was lurking in the soap scum on vinyl shower curtains, sampled 45 shower heads in homes, apartments, hotels, hospitals and public gyms in cities across the country, including Chicago. They found that the shower heads don't just harbor the potentially infectious microbes; they enrich their growth.

"We saw some exceptionally dirty ones in hotels," said study author Leah Feazel. Unfortunately, shower heads have nooks and crannies that make them hard to clean. Products with bleach can temporarily remove many microbes, but they just grow back.

Changing your shower head two to four times a year or switching to a metal one should help reduce the accumulation of bacteria, said Feazel, adding that many people have decades-old shower heads. Bathing is a good option because the water droplets are too large to penetrate into the lungs, making it less likely you'll inhale a pathogen. And letting the water run a few minutes might flush out the bugs.

Chicago Tribune