News & Events

INSTAAR seminar: Biogeography of an emerging pathogen found in household plumbing

Monday, March 05, 2018, 12:15PM - 1:15PM


Noah Fierer



Sievers Room (SEEC room S228)

4001 Discovery Drive, Boulder

Every time we take a shower, we breathe in a large number of aerosolized microorganisms dislodged from the biofilms found inside our showerheads. Most notably, showerheads can harbor large populations of Mycobacteria, a diverse genus of bacteria that includes opportunistic pathogens. Unfortunately, we do not know how the diversity and abundances of Mycobacteria vary spatially or in response to changes in household water chemistry, despite the growing importance of mycobacterial diseases. We recruited >600 volunteer households from across the United States and Europe to sample their showerhead biofilms and conduct basic chemical analyses of their household water. We found substantial variation in the amounts and types of mycobacteria found in showerhead biofilms. Furthermore, we detected strong geographic structure in mycobacterial abundances with a number of mycobacterial strains (including putative pathogens) having higher abundances in selected regions of the U.S. This geographic variation in mycobacterial abundances was often predictable from household water chemistry, with chlorine levels, and other water chemistry parameters consistently selecting for specific mycobacterial taxa. Lastly, our results indicate that certain mycobacteria appear to co-occur with specific micro-eukaryotes, including some amoebae, highlighting a unique ecological strategy used by some mycobacteria to persist in showerhead biofilms. Together these results demonstrate the power of a ‘citizen science’-based approach to improve our understanding of those bacteria living with us in our homes that can have important impacts on human health.

Coffee hour

Light refreshments will be served starting at 11:45 outside room S228.


Free and open to the public.