…an additive of many toothpastes, hand washes and – yes – shower gels, has been shown in a new study to elicit resistance. Non-antibiotic, antimicrobial (NAAM) chemicals had already been linked with the development of resistant bacteria. For example, bacteria with reduced susceptibility to triclosan (a NAAM used in hand-wash) were previously found to have increased cross-resistance to ampicillin, ciprofloxacin and erythromycin. However, the new study refines ‘linked with’, and through experiments using E. coli bacteria exposed to triclosan concentrations that are reasonably expected of the environment, show that this can ‘directly cause’ the development of multi-drug resistance.

The US had already banned tricolsan from hand wash in 2016; but in the absence of any direct evidence (until now), this NAAM has had continued widespread use in numerous household products elsewhere.

Just how much NAAM chemicals contribute to environmental resistance relative to antibiotics used in humans and animals as well as aquaculture is yet another big unknown in AMR. The authors conclude: “To holistically evaluate the potential impact of NAAM chemical use on public health, a cohesive and rigorous understanding of the relationship between NAAM chemicals and global antibiotic resistance dissemination is critical.”

Something to ponder, perhaps, during your next traipse down the supermarket aisles.

By Laith Yakob, head of the Epidemiology and Modelling pillar.