Scientists collected toothbrush samples and were shocked by the hundreds of viruses they found

Scientists have found more than 600 distinct viruses after scrubbing people’s toothbrushes and shower heads – but fortunately, the vast majority of them are more helpful than harmful.

Northwestern microbiologist Erica Hartmann, lead author of a new study published this week in Frontiers in Microbiomescounted Gizmodo that she was equally shocked and fascinated to discover that these everyday objects were teeming with bacteria-eating viruses known as bacteriophages.

“There is so much in the world around us that we don’t understand – including things that may seem familiar,” she explained. “We started looking at things like toothbrushes and shower heads because they are important sources of microbes that we are exposed to, but we don’t know what microbes they carry or what factors influence them.”

The most recent study was an update to the Northwestern team’s 2021 project, “Operation Pottymouth,” which involved investigating the sources of bacteria found on toothbrushes.

Although there was incredible diversity among the more than 600 phage samples, one type that kills disease-causing mycobacteria was slightly more common than any other, Harmann said. Since mycobacteria can cause serious infections such as leprosy and tuberculosis, it is good that the viruses that kill them are also present.

“Toothbrushes and shower heads harbor phages unlike anything we’ve seen before,” said the microbiologist. “Not only do we find different phages on toothbrushes and shower heads, we also find different phages on each toothbrush and each shower.”

In recent years, phages have been studied and used as treatments for bacterial infections, especially those that have mutated to resist antibiotics. While Hartmann insists that these discoveries are captivating in their own right, knowing that they can be used in medical treatments makes them that much more useful.

“It could be,” she said, “that the next big antibiotic is based on something that grew on your toothbrush.”

While it’s not exactly pleasant to think about, it certainly seems a lot better than leaving a mycobacterial infection like tuberculosis or chronic ulcers untreated.

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