Macquarie University research has found a common biocide disinfectant, valued for its non-toxicity, may prevent antibiotics from working and create resistant "superbugs".
Benzalkonium chloride (BAC) is widely used in household products like antibacterial wipes, eye drops, eardrops and disinfectants.
One of the study's leaders Francesca Short says biocides are not regulated in Australia "and there isn't a lot of information on what they are doing to the bacteria they are being used on".
"Our study found BAC could not only prevent aminoglycoside antibiotics from working, but also promote the evolution of resistant bacteria, which is extremely concerning given how widely BAC is used," Dr Short said.
The study – funded by a grant from the National Health and Medical Research Council – found even when administered at low levels, BAC can block aminoglycosides from doing their job, as it prevents the antibiotics from entering the bacterial cell.
It also dramatically increases the frequency at which new, potentially resistant mutants emerge.
"Our results suggest that measures need to be taken to prevent the exposure of bacteria to lower levels of BAC – levels that are not high enough to kill bacteria but may be high enough to allow mutations to occur or help the bacteria gradually get used to the effects of the antibiotics."
Dr Short says consumers should not choose antibacterial products as a default, thinking they provide better protection.
"If you're cleaning around the house, in general there's no need to use anything marked 'antibacterial'," she said.
Ordinary soap and cleaning products will remove nearly all the germs.
"While it's a good idea to use a bleach-based product on your toilet, you simply don't need hospital-grade disinfectant for your bathroom sink or a wipe that leaves an antibacterial residue on your kitchen bench," Dr Short said.
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