Recent Advances in the Microbiology of the Built Environment

It has been just over three centuries since Antonie van Leewenhoek first conclusively documented the biological nature of the elements of air and dust in the built environment [1]. During the 20th century, advancements in sampling instrumentation and analysis techniques yielded a large literature on the microbiology of air and dust, mainly using culture and microscopy [2, 3]. In the past few decades, the measurement of health-relevant biochemicals such as allergens, endotoxin, and glucan in the context of population health studies has contributed substantially to our understanding of how the built environment can influence health. In the past few years, investigations of the built environment using cultureindependent sequence-based analysis have confirmed many previously held expectations about the sources and fates of indoor microbes, and in the process, these methods have also produced several unexpected insights into the indoor microbiome. Perhaps not surprisingly, the biological composition of air and dust appears to be vastly more complex than formerly thought. Over the next decade, molecular metagenomic methods are likely to revolutionize our understanding of the roles of air and dust in the biology of life on earth, and in the process, provide sophisticated new tools to elucidate health-environment interactions. This review summarizes recent key studies on the microbiology of the built environment to date using modern culture-independent methods, and considers the implications of these findings and future studies elucidating the interactions between the humans and the built environment.