Bacteria in Dust

By: Marisol De Leon

There is without a doubt very few instances, if any, where a person is not in contact with a microbe. Maintaining a clean home does not guarantee that it is free of bacteria or fungi as these can be found in dust. In a study done throughout the United States, dust samples from 1100 homes were collected in order to find the fungal and microbial communities found in settled dust. These samples were taken from upper door trim in the main living area and the upper door trim on the outside surface of an exterior door. The study showed that bacteria associated with the skin and faeces such as Streptococcus and bacteroides were more abundant inside homes as was expected. Fungal communities found inside the home varied by climate and geographical regions. Furthermore, bacteria from non-human occupants were also found to be relatively more abundant inside homes. This showed that the composition of bacterial communities found were influenced by the number and types of occupants. As seen in the figure below, 56 and 24 bacterial genera were more abundant in homes with dogs or cats. Also, skin- associated taxa such as Dermobacter were more abundant in homes with fewer women. Lactobacillus was found to be more abundant in homes with women than without women.While trying to eliminate all dust from your home might sound like a good but tiring option, its important to remember that bacteria and fungal communities found in settled dust can depend on the presence and activities of human and non-human occupants as well. 

Figure from Barberan A et al. (2015) shows the differences in proportion of bacteria found in homes with a) dogs or no dogs, b) cats present or absent, and c) homes with more females than males and homes with more males than females.

Barberan A et al. (2015). The ecology of microscopic life in household dust. Proc. R. Soc. B 282: 20151139