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Indoor Microbiome

Contents of this page is subject to copyright laws. Copyright © 2017 Sarah E. Kwan

The Reestablishment of Microbial Communities after Surface Cleaning in Schools

Sarah E Kwan, Richard J Shaughnessy, Bridget Hegarty, Ulla Haverinen‐Shaughnessy, Jordan Peccia

Relative abundance of bacterial and fungal genera found on desk surfaces pre- and post-cleaning categorized as (a) bacteria that is human associated (red), environmentally associated (green), and other bacteria (black); (b) bacteria that is skin associated (blue), oral cavity associated (yellow), gut/fecal associated (orange), and other human associated bacteria (black); (c) fungi that is human associated (red), and other fungi (black); and (d) fungal genera containing allergens (purple), and other fungi (black).

Relative abundance of bacterial and fungal genera found on desk surfaces pre- and post-cleaning categorized as (a) bacteria that is human associated (red), environmentally associated (green), and other bacteria (black); (b) bacteria that is skin associated (blue), oral cavity associated (yellow), gut/fecal associated (orange), and other human associated bacteria (black); (c) fungi that is human associated (red), and other fungi (black); and (d) fungal genera containing allergens (purple), and other fungi (black).

     Aims. The goal of this study was to quantify the indoor microbiome dynamics of bacterial and fungal communities on school desk surfaces during a cleaning intervention.

     Methods and Results. Quantitative PCR and DNA sequenced-based approaches were employed to describe microbial community dynamics on ten desk surfaces, spread across three schools, located in the Northeast region of the U.S. Six samples were taken from each desk, one pre-cleaning, and five post-cleaning at 30 minutes, 1 day, 3 days, 7 days, and 21 days. Cleaning of the desks physically removed ~50% of bacteria, fungi, and human cells and a full recovery of the surface microbial concentrations occurred within 2-5 days. This recovery period is much shorter than the schools’ once per semester cleaning schedule. The dominant source of bacteria and fungi on desks at all time points came from the human microbiome (skin, oral cavity, and gut). More than 50% fungi on desks were members of genera that contain known allergens.

     Conclusions. Microbial communities on these school desks are primarily generated and maintained from the deposition of human-associated bacteria and fungi. Current school surface cleaning protocols and cycles may be ineffective at reducing student exposure to fungal allergens and microbes of human origin.

     Significance and Impact of Study. Multiple students often share desks in schools. Results on the removal and reestablishment of microbial communities on these surfaces are critical for setting cleaning schedules and practices that effectively interrupt exposure to surface-associated pathogens and allergens.


Buildings, Beneficial Microbes, and Health

Jordan Peccia, Sarah E. Kwan

Sources and Physical Processes that Govern Assembly of Indoor Microbial Communities. Other potential sources of microbes may include emission from plants, food, and plumbing.

Sources and Physical Processes that Govern Assembly of Indoor Microbial Communities. Other potential sources of microbes may include emission from plants, food, and plumbing.

Bacteria and fungi in buildings exert an influence on the human microbiome through aerosol deposition, surface contact, and human and animal interactions. As the identities and functions of beneficial human microbes emerge, the consequences of building design, operation, and function must be understood to maintain the health of occupants in buildings.