Viruses, bacteria, fungi, mites… We are surrounded by all types of microorganisms that are not visible to the human eye, but that can make us uncomfortable, although, fortunately, not all of them are harmful. Bathrooms are one of the places that concentrate the most germs, as confirmed by a new study led by Northwestern University, which has revealed that showers and toothbrushes are full of an extremely diverse collection of viruses, most of them which had never been observed. Their findings have been published in the journal Frontiers in Microbiomes.
Although this may sound alarming, the good news is that these viruses do not affect people, but rather attack bacteria, since the microorganisms found in the study are bacteriophages, or “phages”, a type of virus that infects and spreads. reproduces within bacteria. Although researchers still know little about them, phages have recently sparked interest for their potential use in treating antibiotic-resistant bacterial infections. Unknown viruses found in our bathrooms could be a valuable source for exploring such applications.
“The amount of viruses we found is incredible,” said Erica M. Hartmann, an associate professor of civil and environmental engineering at Northwestern’s McCormick School of Engineering, who led the study. “We discovered many viruses about which we know very little and many others that we had never seen. It’s amazing how much unexplored biodiversity surrounds us. And you don’t need to go far to find it; It’s right under our noses.”
Microbes prefer watery environments in the home
This new study builds on previous research, in which Hartmann and his colleagues at the University of Colorado at Boulder characterized the bacteria that live on toothbrushes and showers. In those studies, they asked participants to send in used toothbrushes and shower samples.
Inspired by concerns that a flushing toilet could generate a cloud of aerosolized particles, Hartmann dubbed that study ‘Operation Dirty Mouth.’ “This project started out of curiosity,” said Hartmann. “We wanted to know what microbes live in our homes. If you think about indoor environments, surfaces like tables and walls are difficult for microbes. They prefer environments with water. And where is there water? Inside the showers and on the toothbrushes.”
“Microbes are everywhere and the vast majority will not make us sick.” “The more we attack them with disinfectants, the more likely they are to develop resistance or be more difficult to treat.”
After characterizing the bacteria, Hartmann used DNA sequencing to examine the viruses present in those samples, and she was surprised. In total, the samples contained more than 600 different viruses, and no pair of samples was the same. “We saw virtually no overlap in virus types between showers and toothbrushes,” Hartmann said. “There wasn’t much coincidence between any two samples either. Every shower and every toothbrush is like a little island. “This underlines the incredible diversity of viruses that exists.”
Mycobacteriophages, a potential ally to combat pathogens
Although they found few common patterns in the samples, Hartmann and his team noted a greater presence of mycobacteriophages compared to other types of phages. Mycobacteriophages infect mycobacteria, a type of pathogenic bacteria that causes diseases such as leprosy, tuberculosis, and some chronic lung infections. Hartmann imagines that, in the future, researchers could use these mycobacteriophages to treat these infections.
“We could think about using these mycobacteriophages to clean pathogens in plumbing systems,” explained Hartmann, who is a microbiologist specialized in indoor environments and a member of the Center for Synthetic Biology. “We want to study all the functions these viruses could have and find out how we could use them.”
Meanwhile, the expert advises not to worry too much about the invisible life in our bathrooms. Instead of using harsh disinfectants, he suggests soaking showers in vinegar to remove calcium buildup, or simply washing them with soap and water. She also recommends regularly changing toothbrush heads, although she is not a fan of antimicrobial brushes because they can breed antibiotic-resistant bacteria.
“Microbes are everywhere, and the vast majority will not make us sick,” he assured. “The more we attack them with disinfectants, the more likely they are to develop resistance or be more difficult to treat. We must learn to live with them,” concludes the researcher.
