Your Own Personal Microbial Cloud

A recent study from Meadow et al at the University of Oregon looked at the individual microbiota that humans shed into their surrounding environment. They sequenced the airborne microbes that colonized a sterile chamber once each individual entered. They found that this left a microbially distinct and detectable signature, much like a fingerprint, after 1.5-4 hours. The abstract is as follows:

Dispersal of microbes between humans and the built environment can occur through direct contact with surfaces or through airborne release; the latter mechanism remains poorly understood. Humans emit upwards of 106 biological particles per hour, and have long been known to transmit pathogens to other individuals and to indoor surfaces. However it has not previously been demonstrated that humans emit a detectible microbial cloud into surrounding indoor air, nor whether such clouds are sufficiently differentiated to allow the identification of individual occupants. We used high-throughput sequencing of 16S rRNA genes to characterize the airborne bacterial contribution of a single person sitting in a sanitized custom experimental climate chamber. We compared that to air sampled in an adjacent, identical, unoccupied chamber, as well as to supply and exhaust air sources. Additionally, we assessed microbial communities in settled particles surrounding each occupant, to investigate the potential long-term fate of airborne microbial emissions. Most occupants could be clearly detected by their airborne bacterial emissions, as well as their contribution to settled particles, within 1.5—4 h. Bacterial clouds from the occupants were statistically distinct, allowing the identification of some individual occupants. Our results confirm that an occupied space is microbially distinct from an unoccupied one, and demonstrate for the first time that individuals release their own personalized microbial cloud.

There is also a news article on the topic in the Chicago Tribune.


Here are some other microBEnet posts on the microbial fingerprint of humans:

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Alex Alexiev

Alex Alexiev is a recent UC Davis graduate with a BS in microbiology working in Jonathan Eisen’s lab on aquariums as part of the microbiology of the built environment.