We all emit our own 'microbial cloud'

Every individual has a microbiome compiled of millions of bacteria, fungi, viruses, and other microorganisms that is unique for each one of us. Whenever we travel to a new location and sit down or touch something, we are spreading our microbiome to that new location. A lot of research has gone into this phenomenon and is called the microbiome of the built environment. A new study out of the University of Oregon has expanded on this understanding and has described what they call a “microbial cloud”.

The scientists found that individuals not only spread their microbiome to new locations through direct contact but the microorganisms on our body are also dispersed into the air making up this microbial cloud. To better understand this, the scientists had 11 individuals sit in an enclosed room for 4 hours and they analyzed the DNA from the bacteria in the air. They found that when each individual sat in the room, there were thousands of bacteria in the room and everyone’s was distinct. They were able to identify specific characteristics of the people such as if it was a man or a woman.

The bacterial combinations found in the room could be linked back to specific individuals even after the person inhabited the room for only 4 hours. There were specific groups of bacteria like Streptococcus, often found in the mouth, as well as Propionibacterium and Corynebacterium, often found on the skin, that were most useful in identifying the individuals. While these bacteria were found around all the study participants it was the combination of bacteria that was key to identifying the individuals.

This finding could have several important applications. One often-discussed application of the microbiome is its use in forensic applications. It may be possible to use this ability to identify people and know if they were in a room or not to see if someone committed a crime, though it is not clear if it will be possible to identify people in a crowd of other individuals. Other applications include understanding the spread of infectious disease between individuals and within buildings. This is an exciting new development and I am certain we will see more research looking at our microbial clouds in the future.

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