Researchers from Northwestern University have uncovered a surprising diversity of viruses residing in everyday bathroom items such as showerheads and toothbrushes. The study, published in the journal Frontiers in Microbiomes, revealed over 600 different viruses, most of which were previously unknown. These viruses are bacteriophages, or "phage," which infect bacteria but do not pose a threat to humans.
Erica M. Hartmann, an associate professor at Northwestern's McCormick School of Engineering and leader of the study, expressed astonishment at the findings: “The number of viruses that we found is absolutely wild. We found many viruses that we know very little about and many others that we have never seen before.” Hartmann highlighted the untapped biodiversity present even within our homes.
The research follows earlier work by Hartmann and colleagues at the University of Colorado at Boulder on bacteria living on toothbrushes and showerheads. Dubbed “Operation Pottymouth,” this project was inspired by concerns about aerosol particles generated by flushing toilets. The team collected used toothbrushes and swabs from showerheads to examine their microbial inhabitants.
DNA sequencing revealed a vast array of viral types with no overlap between samples from different sources. Each sample appeared unique, showcasing significant viral diversity. Notably, mycobacteriophage—viruses that infect mycobacteria responsible for diseases like tuberculosis—were more prevalent among the samples. Hartmann speculates these could potentially be harnessed to treat infections or clean plumbing systems.
Despite these findings, Hartmann advises against excessive use of disinfectants due to potential resistance development: “Microbes are everywhere, and the vast majority of them will not make us sick.” Instead, she suggests simple cleaning methods like soaking showerheads in vinegar or replacing toothbrush heads regularly.
The study titled “Phage communities in household-related biofilms correlate with bacterial hosts but do not associate with other environmental factors” received support from Northwestern University.