Bathroom bacteriophages: Unlocking potential in medical research

Scientists from Northwestern University discovered more than 600 types of viruses that infect bacteria. They conducted a thorough examination of toothbrushes and showerheads in bathrooms. Some of these viruses were previously unknown. However, this discovery is not alarming; it presents potential opportunities for advancing a key area of medical research.

As reported in the journal Frontiers in Microbiomes, over 600 types of viruses that infect bacteria, known as bacteriophages, including many previously unknown, were found on toothbrushes and showerheads.

Researchers have long known that toothbrushes and showerheads can harbour various bacteria, originating from both the users' mouths and the water supplied by municipal systems. However, the presence of "bathroom" viruses was less understood until now.

This research was prompted by earlier studies indicating that toilet flushing can produce aerosols that carry bacteria. These findings prompted Erica Hartmann from Northwestern University in Illinois to conduct new research. The team of scientists collected samples from 92 showerheads and 36 toothbrushes in the bathrooms of people living in the United States.

Through DNA sequencing, researchers discovered more than 600 types of bacteriophages — viruses that infect bacteria — on these surfaces. Interestingly, the vast majority were found on toothbrushes. Almost every tested toothbrush served as a habitat for different viruses.

Bacteriophages are viruses that specifically target bacteria but are harmless to humans. They employ two mechanisms: they can take control of bacteria to replicate and subsequently kill the host, or integrate into the bacteria's genome, altering their behaviour. Scientists believe studying bacteriophages could lead to new ways of combating antibiotic-resistant bacteria.

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 — said Erica Hartmann.

The researchers were especially interested in mycobacteriophages, viruses that infect mycobacteria, such as those causing tuberculosis, leprosy, and chronic lung infections. Scientists hope that in the future, mycobacteriophages can be used to treat these serious infections and to purify water supply systems of hazardous pathogens.

The discovered bacteriophages are likely present not only in bathrooms but also on other damp surfaces such as sinks or refrigerator interiors. However, researchers assure that most are harmless.

There is no need to use aggressive disinfectants like bleach. Limescale can be removed from showerheads by submerging them in vinegar or simply cleaning them with soap and water. However, it is important to remember to change toothbrushes regularly.

Research by scientists from Northwestern University in Illinois sheds new light on the invisible world of microorganisms present in our homes. However, while microbes are widespread, they rarely cause diseases. Overusing disinfectants may encourage resistance development in bacteria and other pathogens, complicating treatment with antibiotics, which poses an increasing challenge to medicine.