The most commonly used chemical compounds with the potential to induce antimicrobial resistance and cross or co-resistance in bacteria are the heavy metals, copper, zinc, and cadmium. This is the conclusion in a literature review from the Norwegian Scientific Committee for Food Safety (VKM).
The Norwegian Environment Agency (NEA) requested the VKM to conduct a literature review regarding development of bacterial resistance to biocides and heavy metals and cross-resistance to antimicrobial agents (e.g., antibiotics) in bacteria.
In addition to heavy metals, copper, zinc, and cadmium, phenols, especially triclosan, surface-active agents, especially quaternary ammonium compounds (QACs), and the heavy metals arsenic and mercury are classified in the category “likely”.
The components in the “unlikely” group are aldehydes, biguanides, organic acids, inorganic acids, antimicrobial dyes, diaminides, and silver.
It should be noted that a number of uncertainties are associated with the results.
There is a lack of knowledge regarding the diverse reservoir of antimicrobial resistance in the environment. VKM has not been able to gather sufficient data on the amount of the different biocides and heavy metals that end up, unintentionally, in the environment in Norway and the extent to which such exposure, alone or in combination with other antimicrobials, may result in development of antimicrobial resistance in microbial communities.
Furthermore, limited data are available regarding use/misuse/presence of biocides and heavy metals in consumer products.
Knowledge regarding development of resistance in bacteria due to use of biocides or heavy metals in cosmetic products is lacking.
The literature overview is conducted by VKMs panel on microbial ecology.