Pathogens and microorganisms enriched 100-fold in the daily used shower-head

"Mycobacteria readily form biofilms and, because of their generally waxy quality, may be particularly resistant to shear forces generated in shower operation (28–36). Furthermore, many species of biofilm-forming mycobacteria are chlorineresistant, and thus potentially can be enriched by chlorine disinfection protocols used by many municipalities (28, 29, 34, 37, 38)."

Published online before print September 14, 2009, DOI: 10.1073/pnas.0908446106

Opportunistic pathogens enriched in showerhead biofilms

1. Leah M. Feazela,
2. Laura K. Baumgartnera,
3. Kristen L. Petersona,
4. Daniel N. Franka,
5. J. Kirk Harrisb and
6. Norman R. Pacea,

Abstract

The environments we humans encounter daily are sources of exposure to diverse microbial communities, some of potential concern to human health. In this study, we used culture-independent technology to investigate the microbial composition of biofilms inside showerheads as ecological assemblages in the human indoor environment. Showers are an important interface for human interaction with microbes through inhalation of aerosols, and showerhead waters have been implicated in disease. Although opportunistic pathogens commonly are cultured from shower facilities, there is little knowledge of either their prevalence or the nature of other microorganisms that may be delivered during shower usage. To determine the composition of showerhead biofilms and waters, we analyzed rRNA gene sequences from 45 showerhead sites around the United States. We find that variable and complex, but specific, microbial assemblages occur inside showerheads. Particularly striking was the finding that sequences representative of non-tuberculous mycobacteria (NTM) and other opportunistic human pathogens are enriched to high levels in many showerhead biofilms, >100-fold above background water contents. We conclude that showerheads may present a significant potential exposure to aerosolized microbes, including documented opportunistic pathogens. The health risk associated with showerhead microbiota needs investigation in persons with compromised immune or pulmonary systems.

What should we do?
* no shower? - impossible
* metal shower-head is better than plastic version? - maybe
* replace the shower-head regularly? - maybe
* trust your own immuno-system? - hopefully
* ...

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