Quirks & Quarks

Your dust bunnies are alive but fighting them with antibacterials is a bad idea

Dust microbes have antibiotic resistance genes, probably from overexposure to household antimicrobials

Dust microbes have antibiotic resistance genes, probably from overexposure to household antimicrobials

Contrary to popular belief, dust found in rooms and buildings is alive and teeming with bacteria. (Stromcarlson, cc-by-sa-3.0)

The dust in athletic facilities is actually alive and teeming with bacteria, according to a new study conducted by scientists at Northwestern University.

And perhaps more troubling is that some of these dust bacteria have evolved antibiotic resistance.

Dr. Erica Hartmann, who led the study, suspects that antibiotic resistance genes might have evolved in response to exposure to triclosan, a common anti-microbial found in cleaners and consumer products.

Although the dust bacteria are benign, she fears that the antibiotic resistance genes could jump to pathogenic microbes and lead to hard-to-fight illnesses in humans.

Ryan Blaustein, Erica Hartmann, Alexander McFarland and Sarah Ben Maamar are co-authors on the paper. (Tierney Acott)

What's in your dust

The team conducted the study by visiting 42 athletic facilities in the Pacific Northwest region and vacuuming floors for dust samples.

They then performed DNA sequencing and chemical analysis on the samples, and found a range of bacteria, including ones commonly found in the human microbiome and microbes commonly found outdoors which had been brought in and were living in the building.

Bacteria isolated from dust growing on an agar plate. The photo shows a disc diffusion test, where each disc contains a different antibiotic. The discs covered in growing bacteria contain bacteria that are resistant to antibiotics. (Taylor Brown/Northwestern University)

About a quarter of the more than 7,000 bacterial colonies in the dust were discovered to be resistant to one or more of the three antibiotics the teams tested.

An abundance of triclosan was also found in the dust.

A highly suspicious link

"We've seen in other studies and in other environments that exposure to triclosan can increase resistance to medically relevant antibiotics," Hartmann explained.

Some of the bacteria, she observed, were able to survive in the presence of triclosan.

The bacteria could be using the same strategies it uses to fight triclosan to fight antibiotics, she explained.  

An illustration showing dust samples taken from around an athletics facility. These samples contain bacteria and triclosan, which is represented by a triangle. (Vlad Tchompalov)

Triclosan is an incredibly widespread chemical found in building dust around the world, according to Hartmann. It's highly effective at killing microbes and has been added to many different products for that purpose.  But there has been concern that overuse of triclosan could produce resistant bacteria.

In 2017, it was banned as an ingredient in hand soaps and cleaners in the U.S. However, it's still present in toothpaste and other consumer products that are not labeled.

Lay off the antimicrobials

"Antibiotic resistance is a huge public health issue," said Hartmann. "The fact that we see this association between antibiotic resistance and antimicrobial is very suspicious. We really need to think about when and where and how we are using antimicrobial products and use it more responsibly."

A bottle of antibacterial soap used to contain the active ingredient triclosan before it was banned in 2017. (Getty Images)

According to Hartmann, there's no research showing that antimicrobials are necessary for routine cleaning.

"Unless you have a specific concern, it's probably enough to clean with regular cleaning agents. You don't need the added antibacterial."


To encourage thoughtful and respectful conversations, first and last names will appear with each submission to CBC/Radio-Canada's online communities (except in children and youth-oriented communities). Pseudonyms will no longer be permitted.

By submitting a comment, you accept that CBC has the right to reproduce and publish that comment in whole or in part, in any manner CBC chooses. Please note that CBC does not endorse the opinions expressed in comments. Comments on this story are moderated according to our Submission Guidelines. Comments are welcome while open. We reserve the right to close comments at any time.