Is taking too many bacteria killing drugs the only way to develop a resistance to antibiotics?

Perhaps not.

A new study has linked antimicrobial substances such as triclosan in indoor dust with levels of antibiotic resistance genes.

The research doesn’t confirm that inhaling tainted dust can cause antibiotic resistance, but it indicates that bacteria containing antimicrobial substances are tied to having antibiotic resistance genes.

The report was published today in the journal Environmental Science & Technology.

It is not the first study to identify a link between the antimicrobial triclosan and antibiotic resistance, but it is the first to identify a link to indoor dust.

Read more: Asthma caused by dust mites may damage lung cells »

Chemicals and genes

Erica Hartmann, Ph.D., an assistant professor in civil and environmental engineering at Northwestern University in Illinois, and her team assessed dust samples from an indoor athletic and educational facility.

They found six links between antimicrobial chemicals and antibiotic resistance genes in microbes.

Hartmann explained to Healthline that the antibiotic resistance genes are in the bacteria.

For example, dust with higher triclosan levels had higher levels of a gene that’s been known to cause antibacterial resistance.

Hartmann said the tainted dust is more likely to have antibiotic resistant bacteria in it.

“Bacteria with those genes are then resistant to antibiotics, which means that if they infect a person, the medications doctors would normally prescribe won’t do any good,” she said.

She noted researchers haven’t determined if inhaling the dust could lead to an antibiotic resistant infection.

In addition to triclosan, Hartmann also looked at triclocarban as well as methylparaben, ethylparaben, propylparaben, and butylparaben. Those can be found in everything from personal care products to food.

Read more: How bacteria on your breath could help antibiotic resistance »

More studies needed

The median concentration of triclosan in the study’s indoor dust was small, much lower than amounts used in toothpaste, for instance.

However, Hartmann’s team believes their findings warrant further investigation into how these chemicals in dust may contribute to antibiotic resistance.

She said it’s possible the link could be proven in household dust, too. Currently, Hartmann is conducting a follow-up study to see if those results can be replicated from dust inside homes.

“We don’t know if there’s something special about athletic facilities — or even just this one in particular,” she said.

Philip Smith, Ph.D., an associate professor in terrestrial ecotoxicology at Texas Tech University, said the study was interesting and timely.

“It clearly illustrates that aerial deposition can play a role in dissemination of chemical agents that facilitate development of resistance, and perhaps resistance itself,” he told Healthline.

He added the role of air transportation is not well understood. With more studies, it could help people think about how they use antimicrobial agents.

Read more: High rates of drug resistant bacteria found in children »

Healthy indoor spaces

What can you do to lower the instance of antimicrobial substances in indoor spaces?

Hartmann said not to use them unless they are necessary.

In her follow-up study, Hartmann said she will try to find out if indoor air filtration systems can help.

“We know that whether a building has a mechanical air handling system (like air conditioning), or gets its air directly through the windows, has an effect on which bacteria we find indoors, but we haven’t finished the follow-up study looking at chemicals,” she added.

Another thing you can’t conclude from her study is whether an individual’s antibiotic resistance is due to tainted dust or poor indoor air quality as opposed to antibiotic overuse.

For now, pay attention to the chemicals that you bring into your home, she says.

“The chemicals you bring into your home may stick around for longer than you think and wind up in places they aren’t supposed to, so choose wisely,” she said.

Vacuuming and dusting may help create a cleaner indoor environment but may not do enough, Smith added.

Using filters and limiting antimicrobial products can also help to limit potentially tainted dust.