Viruses are teeming on your toothbrush, showerhead
Northwestern University
In a new Northwestern University-led study, microbiologists
found that showerheads and toothbrushes are teeming with an extremely diverse
collection of viruses -- most of which have never been seen before.
Although this might sound ominous, the good news is these
viruses don't target people. They target bacteria.
The microorganisms collected in the study are bacteriophage, or "phage," a type of virus that infects and replicates inside of bacteria. Although researchers know little about them, phage recently have garnered attention for their potential use in treating antibiotic-resistant bacterial infections. And the previously unknown viruses lurking in our bathrooms could become a treasure trove of materials for exploring those applications.
The study was published Oct. 9 in the
journal Frontiers in Microbiomes.
"The number of viruses that we found is absolutely
wild," said Northwestern's Erica M. Hartmann, who led the study. "We
found many viruses that we know very little about and many others that we have
never seen before. It's amazing how much untapped biodiversity is all around
us. And you don't even have to go far to find it; it's right under our
noses."
An indoor microbiologist, Hartmann is an associate professor
of civil and environmental engineering at Northwestern's McCormick School of
Engineering and a member of the Center for Synthetic Biology.
The return of 'Operation Pottymouth'
The new study is an offshoot of previous research, in which
Hartmann and her colleagues at University of Colorado at Boulder characterized
bacteria living on toothbrushes and showerheads. For the previous studies, the
researchers asked people to submit used toothbrushes and swabs with samples
collected from their showerheads.
Inspired by concerns that a flushing toilet might generate a
cloud of aerosol particles, Hartmann affectionately called the toothbrush
study, "Operation Pottymouth."
"This project started as a curiosity," Hartmann
said. "We wanted to know what microbes are living in our homes. If you
think about indoor environments, surfaces like tables and walls are really
difficult for microbes to live on. Microbes prefer environments with water. And
where is there water? Inside our showerheads and on our toothbrushes."
Diversity and opportunities
After characterizing bacteria, Hartmann then used DNA
sequencing to examine the viruses living on those same samples. She was
immediately blown away. Altogether, the samples comprised more than 600
different viruses -- and no two samples were alike.
"We saw basically no overlap in virus types between
showerheads and toothbrushes," Hartmann said. "We also saw very
little overlap between any two samples at all. Each showerhead and each
toothbrush is like its own little island. It just underscores the incredible
diversity of viruses out there."
While they found few patterns among all the samples,
Hartmann and her team did notice more mycobacteriophage than other types of
phage. Mycobacteriophage infect mycobacteria, a pathogenic species that causes
diseases like leprosy, tuberculosis and chronic lung infections. Hartmann
imagines that, someday, researchers could harness mycobacteriophage to treat
these infections and others.
"We could envision taking these mycobacteriophage and
using them as a way to clean pathogens out of your plumbing system," she
said. "We want to look at all the functions these viruses might have and
figure out how we can use them."
Most microbes 'will not make us sick'
But, in the meantime, Hartmann cautions people not to fret
about the invisible wildlife living within our bathrooms. Instead of grabbing
for bleach, people can soak their showerheads in vinegar to remove calcium
buildup or simply wash them with plain soap and water. And people should
regularly replace toothbrush heads, Hartmann says. Hartmann also is not a fan
of antimicrobial toothbrushes, which she said can lead to antibiotic-resistant
bugs.
"Microbes are everywhere, and the vast majority of them
will not make us sick," she said. "The more you attack them with
disinfectants, the more they are likely to develop resistance or become more
difficult to treat. We should all just embrace them."
The study, "Phage communities in household-related biofilms correlate with bacterial hosts but do not associate with other environmental factors," was supported by Northwestern University.