Scientists identified more than 600 viruses in samples taken from bathrooms in the United States. The viruses infect bacteria — not people — and scientists say they may provide more benefits than causes for concern.

No one showerhead or toothbrush bristle is the same, with US researchers finding a rich, diverse world of viruses living in biofilms coating surfaces in bathrooms across the US and Europe.

Northwestern University researchers identified more than 600 different viruses on 92 showerhead and 34 toothbrush samples — and no two samples were alike.