Office Space Bacterial Abundance and Diversity in Three Metropolitan Areas

Abstract

People in developed countries spend approximately 90% of their lives indoors, yet we know little about the source and diversity of microbes in built environments. In this study, we combined culture-based cell counting and multiplexed pyrosequencing of environmental ribosomal RNA (rRNA) gene sequences to investigate office space bacterial diversity in three metropolitan areas. Five surfaces common to all offices were sampled using sterile double-tipped swabs, one tip for culturing and one for DNA extraction, in 30 different offices per city (90 offices, 450 total samples). 16S rRNA gene sequences were PCR amplified using bar-coded “universal” bacterial primers from 54 of the surfaces (18 per city) and pooled for pyrosequencing. A three-factorial Analysis of Variance (ANOVA) found significant differences in viable bacterial abundance between offices inhabited by men or women, among the various surface types, and among cities. Multiplex pyrosequencing identified more than 500 bacterial genera from 20 different bacterial divisions. The most abundant of these genera tended to be common inhabitants of human skin, nasal, oral or intestinal cavities. Other commonly occurring genera appeared to have environmental origins (e.g., soils). There were no significant differences in the bacterial diversity between offices inhabited by men or women or among surfaces, but the bacterial community diversity of the Tucson samples was clearly distinguishable from that of New York and San Francisco, which were indistinguishable. Overall, our comprehensive molecular analysis of office building microbial diversity shows the potential of these methods for studying patterns and origins of indoor bacterial contamination. “[H]umans move through a sea of microbial life that is seldom perceived except in the context of potential disease and decay.” – Feazel et al. (2009).

Indoor-Air Microbiome in an Urban Subway Network: Diversity and Dynamics

“…Indeed, previous investigations of the effects of urbanization on microbial communities in Hong Kong revealed no variation between urban and rural areas (50). Alternatively, geographical variations that may explain differences in outdoor and/or indoor microbial communities may need to be on a regional rather than a local scale (22,23,51), mediated by great variations in climates in the atmosphere (52). In agreement, the microbial communities in the Hong Kong MTR were distinct from those of other studies in the United States (5, 36), revealing clustering based on continental geography.…”

“…According to the only sequencing-based subway microbiome study conducted to date (21), subway air is made up predominantly of a small number of microbial phyla and families, and its community composition resembles that of outdoor air. While this study provides a more complete analysis of the subway microbiome, it is currently unknown whether the findings from the study can be extrapolated to subway networks of different regions around the globe, as different subway networks are architecturally distinct, and variations in geographic and demographic factors also may contribute to variations in microbiomes of built environments (22)(23)(24). Moreover, as all previous studies analyzed only air samples collected in stationary locations along platforms or concourses of a limited number of stations, the microbial communities described may not necessarily represent the repertoire of microorganisms a typical commuter is exposed to.…”

Surface Microbes in the Neonatal Intensive Care Unit: Changes with Routine Cleaning and over Time

“…By parallel sequencing of short amplicons, typically 16S rRNA genes in bacteria and internal transcribed spacer (ITS) domains in fungi (8), it is possible to comprehensively profile the microbial composition of diverse environments. Microbial communities in intensive care units (ICUs) (9), hospitals (10), public restrooms (11), wineries (12), and office spaces (13) have been explored using high-throughput amplicon sequencing, advancing our knowledge of microbial trafficking and colonization in these systems. A recent report on bacterial communities on the surfaces in two NICUs demonstrated significant diversity and supported the hypothesis that colonies of pathogens on NICU surfaces may increase the risk of infection for premature infants (14).…”

Recovery and biogeography of Pseudomonas and Burkholderia species from the human home.

“…Several studies have been conducted examining the microbiome of various indoor sites including: airplanes (Osman, et al 2008), daycares/schools (Andersson, et al 1999;Liu, et al 2000), kitchens (Flores, et al 2012), office spaces (Hewitt, et al 2012), restrooms (Flores, et al 2011), and homes (Täubel, et al 2009). As a results of these Environmental conditions can also play a role in the microbiome of the built environment.…”

“…In addition to seasonal variability, Moschandreas and colleagues (2003) examined indoor air of Chicago-area homes for differences by room of the home, and found no differences at this spatial scale. Microbial communities differ between different office buildings of the same city (Rinatala, et al 2008) and between office buildings in different cities (Hewitt, et al 2012), indicating that environmental factors, such as climate, may be important in influencing microbial community composition of indoor sites. In addition, differences variability by examining house-to-house variability in recovery, and variation in recovery by type of environment.…”