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- Albrecht, Lisa M, et al.
(författare)
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Mutation in the Copper-Induced sil Operon Enables High-Level Silver Resistance and Silver Facilitated Co-Selection of Multidrug Resistance Plasmid
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Human activities are responsible for an accumulation of metals in health care and agricultural environments, and plasmid-encoded metal tolerance operons enable bacteria to rapidly adapt to metal exposure under such conditions. While the mechanisms of action of many metal resistance systems have been described, there is still limited understanding of their role in co-selection of antibiotic resistance in metal-containing environments. Whether plasmid-encoded metal resistance genes confer significant selective advantages is of interest as it has implications for plasmid enrichment and the spread of plasmid-borne antibiotic resistance genes. To increase our understanding of plasmid-mediated metal resistance, we studied the sil operon and its phenotypes in E. coli during growth in the absence and presence of silver and copper. We found that the sil operon provides resistance to both silver and copper. However, it is induced by copper only, and constitutive expression due to point mutations in the two-component silS gene provides high-level silver resistance. Furthermore, we showed that a high-level silver resistant mutant could be enriched in the presence of silver. This enrichment entailed co-selection of the multidrug resistance plasmid pUUH239.2. Our results show that a copper resistance operon can provide high-level silver resistance following a single point mutation, and that the silver resistance phenotype subsequently can co-select for antibiotic resistance in the presence of silver.
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