Researchers from the University of Colorado analysed the dust from 1,200 households across the USA. The average household had more than 2,000 different types of fungi. These included well-known moulds such as Aspergillus, Penicillium, Alternaria and Fusarium. Most fungi appeared to be coming from outside the home, probably entering the home on clothing, or through open doors and windows. Researchers also discovered an average of 7,000 different types of bacteria per household. Some, such as Staphylococcus and Streptococcus, were commonly associated with human skin. Others, such as Bacteroides and faecalibacterium, were linked to faeces. But here, the species varied according to who – or what – was living in the house.
There were distinctions between homes that had women and homes that were male-only; this is not surprising because there are some kinds of bacteria that are more common on women's bodies than on men's." Pets also had a significant effect on the bacteria found in the homes. The researchers now want to find out how sharing our homes with these organisms could affect human health. While some microbes may be linked to disease and allergies, they say most are probably harmless – and some may even be beneficial.
Dr Fierer, the study author said: "People do not need to worry about microbes in their home. They are all around us, they are on our skin, they're all around our home – and most of these are completely harmless. "It is just a fact of life that we are surrounded by these microbes”.
The study is published in: Proceedings of the Royal Society B, Published 26 August 2015. DOI: 10.1098/rspb.2015.1139