Published paper: MIC distributions for biocides and metals

I am very happy to report on our most recently published paper – and the first one I have co-authored with my PhD supervisor Joakim Larsson in more than six years – which is a product of the BIOCIDE project. In the paper, published in FEMS Microbiology Ecology, Daniel Jaén-Luchoro has been collecting hundreds of MIC data points for biocides and metals to create the first complete and relatively comparable (more on that in a bit) dataset of bacterial sensitivity data for biocides (1).

This was a much bigger undertaking that in might sound like, but it is important for out understanding of how potent metals and biocides are for inhibiting bacterial growth. Basically, Daniel has been putting together an entire EUCAST (2,3) for biocides and metals, which is potentially extremely useful. This in turn can be used to better estimate the risks for co-selection of resistance to antibiotics.

Daniel was able to collect data for 53 antibacterial biocides, 21 metals, and 17 related compounds, resulting in 20,378 MIC values across 164 bacterial species. Of course the data is very overrepresented by clinically relevant organisms, including Staphylococcus aureus and Escherichia coli. Also, certain biocides were studied more than others, such as chlorhexidine and benzalkonium chloride, which was also true for metals that were mostly represented by copper, zinc, arsenic, cadmium and silver.

Importantly, we saw that there is a variety of method to measure MICs for biocides and metals, which means that a lot of the data is not directly comparable. Also, some authors did not even report the exact conditions they measured MICs under. This emphasizes the urgent need for standardized susceptibility testing methodology and consistent terminology for research on biocide and metal resistance. By centralizing MIC data, we provide an important foundation for future efforts to assess ecological risks and co-selection with antibiotic resistance. We aim to integrate this into an update to the BacMet database (4,5) that hopefully will be come available in the near future!

References

1. Jaén-Luchoro D, Larsson DGJ, Bengtsson-Palme J: Bacterial sensitivity distributions for biocides and metals. FEMS Microbiology Ecology, Advance article fiag075 (2026). http://dx.doi.org/10.1093/femsec/fiag075
2. https://mic.eucast.org
3. Kahlmeter G, Turnidge J: Wild-type distributions of minimum inhibitory concentrations and epidemiological cut-off values—laboratory and clinical utility. Clinical Microbiology Reviews 36:e00100-22. https://doi.org/10.1128/cmr.00100-22
4. http://bacmet.biomedicine.gu.se
5. Pal C, Bengtsson-Palme J, Rensing C, Kristiansson E, Larsson DGJ: BacMet: Antibacterial biocide and metal resistance genes database. Nucleic Acids Research, 42, D1, D737–D743 (2014). http://dx.doi.org/10.1093/nar/gkt1252