What’s Growing in My Showerhead?

Have you ever wondered what microbes are brewing in your showerhead? The Showerhead Microbiome Project is finding out! This project, run by a multi-institution group of researchers, is identifying what microbes live in showerheads and how the physical properties of the water and showerhead type may influence the microbial communities.

But why should we even care about showerhead microbes?

From the medical perspective, the microbes living in our showerheads and raining on us every time we jump in the shower could impact our health. Aside from the medical importance, learning about showerhead microbes is just plain awesome. Showerheads are a unique environment for microbial life, one that sustains frequent periods of wetness and dryness. The microbial societies that survive in such fluctuating conditions could clue us in into how microbes form and maintain communities.

The Showerhead Microbiome Project enlisted community members from all over the US to participate in sampling their showerheads. I was excited to find out what sorts of microbes live in my showerhead. Of course, I have never tried to disassemble and clean my showerhead before and was pleasantly surprised that it wasn’t covered in slimy gunk inside.

I swabbed the inside of my showerhead and used paper testing strips to obtain measurements from the water (pH, chlorine levels, iron levels, etc.) and mailed the materials back. Several months later, I received an email stating that the results are in. I followed the link in the email and found a map that pinpoints sampling locations and microbes identified (at the genus level).

Each dot represents a sample from a showerhead. Click here to go The Showerhead Microbiome Project’s website to view the interactive map. Map created by Lauren Nichols and Neil McCoy.

From my showerhead, most microbes identified were unknown (63.75%), followed by Mycobacterium (31.34%), Sphingomonas (3.28%), and Sphingopyxis (1.05%). The abundance of the rest of the microbes was less than 0.5%.

When you think of mycobacterium, tuberculosis (caused by Mycobacterium tuberculosis) and leprosy (caused by Mycobacterium leprae) jump to mind. Surely, these pathogens can’t be living in my shower, right? The Mycobacterium genus consists of over 190 species, including non-pathogens found in soil, tap water, estuaries, and dust. However, Mycobacterium avium, was identified 20% of showerheads from an earlier study from Norman Pace’s lab. M. avium is an opportunistic pathogen that causes chronic pulmonary disease, particularly in people with immunodeficiencies. M. avium can cause disease only when it is aerosolized i.e. when showers produce a fine mist of water droplets. In an interview with NPR’s Ira Flatow, Pace advises taking baths instead of showers to avoid contracting M. avium if you are concerned or immune compromised.

After clicking around on the map provided from the Showerhead Microbiome Project, I noticed that microbial communities varied greatly from showerhead to showerhead. Even those down the street from my apartment were very different than what was identified from mine.

“To be alive is to be, constantly, bathed in life. We live in harmony with most of the microbes around us most of the time.” –The Showerhead Microbiome Project  

As different as my own personal microbiome is from someone else’s, my showerhead may be just as unique. Microbes are everywhere and the showerhead is no exception.

CC BY-NC-ND 4.0 What’s Growing in My Showerhead? by Jennifer Tsang is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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