CHICAGO, April 18 (Xinhua) -- Researchers at Northwestern University (NU) caution that antimicrobial paints, which offer the promise of extra protection against bacteria, might be doing more harm than good.
In a study, the researchers tested bacteria commonly found inside homes on samples of drywall coated with antimicrobial, synthetic latex paints. Within 24 hours, all bacteria died except for Bacillus timonensis, a spore-forming bacterium.
Spore-forming bacteria, such as Bacillus, protect themselves by falling dormant for a period of time. While dormant, they are highly resistant to even the harshest conditions. After those conditions improve, they reactivate.
"If you attack bacteria with antimicrobial chemicals, then they will mount a defense," said Erica Hartmann, an assistant professor of civil and environmental engineering in NU's McCormick School of Engineering. "Bacillus is typically innocuous, but by attacking it, you might prompt it to develop more antibiotic resistance."
"When it's in spore form, you can hit it with everything you've got, and it's still going to survive," said Hartmann. "We should be judicious in our use of antimicrobial products to make sure that we're not exposing the more harmless bacteria to something that could make them harmful."
One problem with antimicrobial products such as these paints is that they are not tested against more common bacteria.
The study was published online on April 13 in the journal Indoor Air.