The global trend towards urbanization has increasingly bound us to the indoor environment. In the developed world, the majority of people spend greater than 90% of their lives indoors, yet we know very little about the bacterial interactions we share with these built environments, and the extent to which they shape the microbiota of indoor ecosystems and of ourselves. Although human-microbe interactions have been shaped by hundreds of thousands of years of co-evolution, the spaces we inhabit are largely constructed of materials that did not exist a century ago, leaving open the question of whether we are the dominant sources of microbes to our built environments, and to what extent the microbial communities of our indoor environments resemble our own. My research uses multidisciplinary methods drawn from ecology, evolution, and bioinformatics to answer fundamental questions about human microbial interaction with the built environment.

Adapted from Lax et al., 2014 (Science)

Adapted from Lax et al., 2014 (Science)

What factors structure the microbial communities of the built environment? 

One of the central goals of my research is to disentangle the myriad biotic and abiotic factors that influence the structure of built environment microbial communities, so that we can ultimately understand the origins of the microbiota we interact with on a daily basis. My research uses longitudinal surveys of microbial interaction between the built environment and its occupants to asses how microbial communities assemble, evolve, and are altered by perturbations such as cleaning or a change in occupancy. Much of this research is tied to the Gilbert lab's home and hospital microbiome projects. 

 

 
Adapted from Lax et al., 2014 (Science)

Adapted from Lax et al., 2014 (Science)

How are microbes vectored throughout the environment?

Human skin and respiratory cavities harbor a vast array of microbial consortia that can be readily dislodged and transferred to their surrounding environment. Such communities are extremely diverse, with great variation both between individuals and between different body sites of the same individual, yet they are sufficiently stable over time that interpersonal variation exceeds temporal variation, even across sampling intervals of many months. I’m interested in the extent to which microbial communities of home surfaces resemble those of their occupants, and in determining common microbial interactions between the human and home environments. This in an important component of our Hospital Microbiome Project (www.hospitalmicrobiome.com), as the way in which potentially pathogenic taxa move throughout the hospital environment has obvious medical implications. Ultimately, a deeper understanding of how bacteria move between a building and its occupants may allow us to design buildings better suited to health and safety.