Another reason for a spring clean (Image: Oleksiy Maksymenko/Getty Images)

IF YOU thought the bacteria that line our gut were pretty personal, think again. They influence our digestion, risk of disease, and even our behaviour. Now it seems we might be sharing these gut bugs with the people around us – via dust.

James Scott at the University of Toronto in Canada and his colleagues investigated the bacterial make-up of faeces from 20 three-month-old babies, which represents the bacteria in their gut flora. The group then compared the faecal bacteria with bugs found in dust samples collected from each baby’s home.

They found a significant overlap in bacterial communities in a baby’s faeces and dust from their home. This suggested that a baby may be sharing their gut bacteria with the environment and vice versa. Scott presented the findings at the International Human Microbiome Congress in Paris, France, last month.


“There are lots of skin microbes in dust, but we don’t expect gut bacteria to be able to escape,” says Scott. This was especially surprising since most known gut bacteria thrive in oxygen-free environments and die in the air, says Scott.

There are lots of skin microbes in dust, but we don’t expect gut bacteria to be able to escape

The bacteria may be releasing their DNA in packages called spores. These hardy vessels allow bacteria to survive harsh environments and they only start reproducing when a more suitable habitat turns up. Scott reckons that faecal bacteria may get into the environment via dirty diapers, unwashed hands, or even the spray from a toilet when it is flushed.

The specific collection of bacteria in our guts has been linked to various diseases and might even influence behaviour. So the findings suggest that people living in the same dusty house may also share health and behavioural characteristics, says Pilar Francino at the University of Valencia in Spain, who was not involved with the work.