Most people can tell who lives in a house by looking at the furniture, how fixtures are arranged, what's in the fridge or what colors were used on its walls or curtains. For scientists at the University of Colorado Boulder, it's bacteria found in household dust.
The organisms in household dust can determine who lives in a certain home, where it is located and what pets live there, according to a new study.
In their findings published Aug. 26 in the online journal Proceedings B of the Royal Society, the researchers used DNA sequencing, along with high-tech imaging, to look deeper into dust samples and determine where the organisms came from.
According to Noah Fierer, professor of Ecology and Evolutionary Biology and fellow at the University's Cooperative Institute for Research in Environmental Sciences, and senior author of the study, millions of bacteria and fungi can be found in our homes. They were able to analyze these bacteria and fungi through dust samples scooped up from the ledges above doorways which were sent by volunteers from 1,200 homes across the U.S. The scientists were particular with dust collected from ledges above doorways - a spot often missed when cleaning.
The team found that most indoor fungi originates from outside of the home, pointing out that geographical location can tell what types of fungi exist within the dust.
The researchers also found that where there are more men, dust contains more skin and fecal-associated bacteria. Where there are more women, household dust somehow attracts more vaginally shed bacteria.
Possible factors that may lead to men shedding off more skin-associated species (Corynebacterium and Dermabacter) and fecal-associated bacteria (Roseburia) are body size, relative abundance and hygiene, the researchers said.
As for women, the presence vaginal-associated bacteria (Lactobacillus) proves that microorganisms are not necessarily fully spread by the clothes we wear, but by what our body produces. In previous research, Lactobacillus was found to protect against asthma and allergies. In this recent study, researchers noted that the Lactobacillus-containing household dust still needs to be further analyzed, to determine its impact to human health.
Animals, pets and insects also predicted the presence of bacteria in the dust samples. Just by looking at the bacteria in the household dust, the researchers were able to predict if dogs or cats lived in a home, with an accuracy of about 92 percent.
While they were able to determine the types of bacteria and fungi present in a home and determine where these organisms come from, the researchers said that more studies need to be conducted to look at their impact to human health.
Photo: Mary Clark | Flickr
