A Home’s Story, Told in Dust, Bacteria and Fungi

An analysis of dust from 1,200 homes across the continental United States provides new information about the fungal and bacterial communities sharing the great indoors with us.

“Our homes are ecosystems that we spend a lot of time in, and so we approached this with a very general question,” said Noah Fierer, a microbial ecologist at the University of Colorado at Boulder and one of the study’s authors. “What type of microbes and fungi do we see in our homes?”

The study, which appears in Proceedings of the Royal Society B, found the types of bacteria found in a house were significantly influenced by the female-to-male ratio of its residents and whether pets were present. Indoor fungal communities, on the other hand, depend largely on the location of the home.

“Most fungi are coming from outside via windows, ventilation and your clothing,” Dr. Fierer said.

He and his colleagues recruited citizens to provide samples of dust on the upper trim of a door in their homes, which usually collects dust and is infrequently cleaned.

“This is baseline data,” Dr. Fierer said. “We’re starting to get a handle on what sorts of microbes we see in homes, and the next step is looking at how this affects human health.”