Skip to main content

Table 1 The analogy of a building to a human body and roles of the microbiome in each

From: Toward a microbial Neolithic revolution in buildings

Doors as the mouth

Humans are a major source of indoor microbes. Contagion of pathogens is well documented. The transfer of a health-promoting microbiome through buildings is plausible but not demonstrated [73], i.e., the possibility of healthful analogs of “Typhoid Mary” [74].

Outer surfaces of a building and human skin

The barriers between inside and outside are semipermeable and somewhat selective. So far, the microbiome studies of buildings have focused on interior spaces. External surfaces and interstices of buildings are a source of interior microbial presence [11].

Lungs as the HVAC system, windows, and walls (especially pre-energy efficiency walls)

HVAC systems are notorious in cases of pathogen growth and dispersal. They are also candidates for monitoring and perhaps cultivation of a benign microbiome rather than attempt sterile systems constantly at risk of dangerous inoculation. HVAC, doors, and windows are sites of intended and unintended exchange with the outer environment. Windows allow unfiltered access to outdoor air. This may be a key to the prevention of asthma in farm environments, i.e., there may be a benefit from microbial diversity originating from active microbes outside, but metabolically inert inside, the building.

Plumbing as the digestive system and excretory system

The inside of wastewater plumbing may be coated in biofilm. Any presumption of complete isolation of this wastewater microbiota from occupants merits re-evaluation. Analogous to the discussions of human inoculation at birth, a building’s wastewater system is a candidate for pre-occupant deliberate inoculation with a benign microflora. We do not at this time know what such an inoculation would consist of, how stable it would turn out to be, and what its consequences would be during normal function and during times of stress such as sewage overflow or burst pipes.

The nervous system as thermostats, alarms, and smart networked buildings

The information on metabolism of buildings is currently limited. For microbes, the single most important information would be monitoring of moisture in many—including hidden such as wall interior—locations. Sentinel microbes could complement electronic measures. Human occupants and their choices (e.g., whether to open a window and ventilate, where to set the thermostat) participate in a building’s nervous system!