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Your Microbes Will Follow You When You Move Home

microbial aura

Image credit: A detailed analysis of the microbes that live in houses and apartments shed light on the complicated interaction between humans and the microbes that live on and around us / Argonne National Laboratory

According to a new study published in the recent edition of Science, home is the place where millions and millions of microbes are harbored. A different microbial community exists at each single household. Whenever we go somewhere, our microbiological auras follow us as well and such microbes can fill our new homes just for one day.

As Jack Gilbert from Argonne National Laboratory said, it was known that certain bacteria can enable mice to gain weight easily while others can affect brain development. Scientists were eager to know where these bacteria originated from. As people spend more and more time outsides, they wanted to identify those microbes living in people’s homes and figure out the possibility that they would settle on people.

Being engaged in the Home Microbiome Project, Gilbert’s team had studied seven families consisting eighteen people, three dogs, and one cat and their houses for the period of six weeks. During their study, scientists collected daily swabs and then sequenced the genomes of bacteria harbored over the skin of each family member and pet as well as household surface including countertops, doorknobs, floors and light switches.

Based on 1,586 different samples, scientists mapped out 4 million DNA sequences and 21,997 distinct genomes (or operational taxonomic units, OTUs). It was found without surprise that the microbial communities on hands, feet, and noses did reflect those on the home surfaces: Doorknobs looked like hands and floors looked like feet. And those homes with indoor-outdoor dogs or cats got more plant and soil bacteria.

By monitoring the transfer of OTUs, Gilbert’s team discovered that people play more active role as sources of bacteria than household surfaces. For instance, the potentially pathogenic Enterobacter was found to be on a person’s hands at first, and then appeared over the kitchen counter, and later on another person’s hand.

And it could occur so rapidly. If some person leaves the house just for a few days, his aura would quickly diminish. And if these three families move to a different house or apartment, even if one family moves from a hotel room to a house, it just takes a half day for the microbial signature of the new abode to look just like that of the old digs.

People often say that someone else stay in this room and it has their microbes all over it. To the eyes of Gilbert, it was irrelevant, because people continuously overwrite the microbes with their own in the place around them.

In comparison with other people, those living in the same house do more microbes in common with each other, just like roommates, couples and parents who share more same microbes at the different level based on how intimate they are. However, people always have kind of unique microbial signatures, wherever they move or stay at home.

In the future, home microbiome signatures could be applied as a useful forensic tool to catch criminals. Talking of their study, Gilbert said that possibly they could easily predict which family it came from. And in the theoretical sense, this new technique would be helpful in detecting a new relationship or uncovering a cheating partner.

Journal reference: Lax, Simon, et al. “Longitudinal analysis of microbial interaction between humans and the indoor environment.” Science 345.6200 (2014): 1048-1052.