Toothbrushes and Showerheads Have a 'Wild' Amount of Viruses, Study Says—but That Might Not Be Bad

But wait! Don't break out the bottle of bleach just yet.

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There are an infinite number of microbes in our homes and bodies, and conventional wisdom encourages us to bleach our showerheads, get antimicrobial toothbrushes, and otherwise minimize our exposure to these “bad” germs. But what if some of these bacteria and viruses weren’t so harmful after all?

In a new study released by Northwestern University, microbiologists discovered hundreds of previously unidentified viruses (or bacteriophages) on showerheads and toothbrushes. Before alarm bells sound, these viruses aren’t the COVID-19 variety—and some of them could even benefit human health. Here’s what’s hiding in your bathroom and what these microbes mean for your cleaning routine.

For microbiologist Erica Hartmann, PhD, the virus study began as a “curiosity” aimed at identifying microbial communities in the home. The team evaluated toothbrushes and showerheads specifically because microbes thrive in moist environments like the bathroom.

After collecting samples, the scientists used DNA sequencing to identify any viruses—more than 600 different bacteriophages were found, and no two samples were alike. Hartmann found the sheer number of viruses “absolutely wild,” she said in a press release.

What’s more, there were significant differences between the toothbrush and showerhead virus communities despite both existing in the bathroom. “Each showerhead and each toothbrush is like its own little island,” Hartmann said in the press release. She added that there’s an incredible diversity of viruses that researchers are only just beginning to understand.

Despite no two samples being alike, some patterns were discovered, including several instances of mycobacteriophages. These viruses infect mycobacteria, which, according to the press release, cause diseases like leprosy, tuberculosis, and chronic lung infections. The authors presume that with further research, these viruses could be used to treat these sometimes deadly bacteria-driven conditions.

Phages (like the ones found in this study) are viruses that don’t infect human cells. “All viruses need to infect cells in order to multiply. Bacteriophages (phages, for short) are viruses that use bacterial cells to multiply, often killing them in the process,” says microbiologist Kathryn Kauffman, PhD.

As far as their impact on human health, bacteriophages have huge potential for treating antibiotic-resistant bacterial infections. “Ever since they were discovered over 100 years ago, people have recognized that phages can be used like medicine to protect us by killing bacteria that make us sick. That is the basis of the field of 'phage therapy.’” says Kauffman.

Every human is home to millions and millions of phages; they are a natural part of our healthy microbiomes.

Regarding the mycobacteriophages found on showerheads and toothbrushes, the authors hypothesize that someday, these viruses could act as “cleaners,” removing harmful bacteria from plumbing systems. Most researchers will tell you, though, not to take on the heavy-duty cleaning yourself.

“Microbes are everywhere, and the vast majority of them will not make us sick,” Hartmann said in the press release. “The more you attack them with disinfectants, the more they are likely to develop resistance or become more difficult to treat.”

Kauffman shares that sentiment, adding, “Phages are a part of our daily lives; finding them is no cause for concern—and, the more we look, the more chances we have to learn about microbes and what is happening in our environments and our bodies.”

If you want to take action, Hartmann advises against antimicrobial toothbrushes (these products encourage antibiotic resistance). Simply replace your toothbrush with a new one regularly, as usual. She also says to skip the bleach and clean your showerhead with vinegar or soap and water to remove calcium deposits.