Hundreds of Different Viruses Are on Your Toothbrush and Shower Head

Microbiologists say these viruses may actually be beneficial and attack bacteria that could make you sick.

Every time you set foot in your bathroom, you’re probably sharing the space with hundreds of different viruses that lurk on surfaces like your toothbrush and shower head, a new study suggests.

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While this sounds gross, and might have you reaching for the bleach to sanitize everything in sight, there’s no need to panic, says senior study author Erica Hartmann, PhD, an associate professor of civil and environmental engineering at Northwestern University in Evanston, Illinois.

“Microbes are everywhere, and the vast majority of them will not make us sick,” Dr. Hartmann says. “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.”

What scientists found in the lab belong to a category of viruses called bacteriophages, which don’t infect people. Instead, bacteriophages target bacteria — including lots of organisms that can cause serious and potentially life-threatening human diseases.

No two samples taken from toothbrushes or shower heads were the same, and scientists found few patterns to identify common clusters of organisms that might thrive in certain bathroom environments.

“Bacteria in our mouths are different from those on shower heads, so it should be expected that the bacteriophage populations from the two locations would be different,” says Robert Schooley, MD, a professor of infectious diseases and global health at the University of California in San Diego, who wasn’t involved in the new study.

However, scientists did find one specific type of virus more often, mycobacteriophage, which infect mycobacteria. These are bacteria that cause specific diseases in humans, including leprosy, tuberculosis, and chronic lung infections, according to the study.

It’s possible that bacteriophages might be used in the future to target bacteria that cause these diseases or other human illnesses, and that they might one day help treat illnesses caused by bacteria that don’t respond to antibiotics, according to the study.

“Penicillin comes from moldy bread,” Hartmann says. “It could be that the next great antibiotic will be based on something that grew on your toothbrush.”

The new study, of course, only offers preliminary lab findings that might eventually become the basis for experiments to test the potential of bacteriophages as a medical treatment. Going from lab tests to human trials to an approved medicine takes years of research and often involves many dead ends along the way.

For now, there’s nothing you need to do to change up your bathroom routine or how you clean, says Graham Hatfull, PhD, a biotechnology professor at the University of Pittsburgh, who wasn’t involved in the new study.

“It is good to keep your bathroom and bathroom items as clean as possible of course, because this is an effective way to reduce the numbers of potentially harmful bacteria, just as it is helpful to wash hands frequently,” Dr. Hatfull says. “But don’t worry about the phages. They are our friends.”

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