Taking a shower should get you clean, right? For some, however, something as simple as standing under the shower head could cause a dangerous lung disease.
Researchers have discovered abundant colonies of mycobacterium growing in the slimy "biofilm" that lurks inside residential shower heads — and for some people, exposure to this bacterium can cause nontuberculous mycobacterial (NTM) lung disease. This is especially true where the malady is most prevalent — Southern California, Florida and New York.
"There is a fascinating microbial world thriving in your shower head and you can be exposed every time you shower," said study leader Noah Fierer in a statement. "Most of those microbes are harmless, but a few are not, and this kind of research is helping us understand how our own actions — from the kinds of water treatment systems we use to the materials in our plumbing — can change the makeup of those microbial communities."
Fierer, a Cooperative Institute for Research in Environmental Sciences fellow and professor of ecology and evolutionary biology at The University of Colorado-Boulder, and his research team, tested 656 samples from locations across the United States and Europe and published their findings in the January, 2019 issue of the American Society for Microbiology's journal mBio.
One of the study's findings confirmed that the incidence of mycobacteria is more common in municipal water than well water, and in the United States as opposed to Europe, according to Fierer. The study also found that metal shower heads are more susceptible to mycobacteria overgrowth than plastic shower heads. Plastic leaches chemicals over time that encourage diverse bacteria, which could prevent the mycobacteria from taking over.
It may be a relief to discover just how easy it is to clean a shower head. Put vinegar and a few drops of bleach in a plastic baggie and seal it over the shower head for a few hours. If this doesn't do the trick, consider replacing the shower head on a regular basis.