Bacterial resistance evolution on antimicrobial surfaces: Mechanistic insights from a standardizable method
- Introduction: Antimicrobial surfaces and coatings (AMCs) are important to prevent the spread of pathogens, especially in hygiene-sensitive areas. However, the evolution and selection of bacterial resistance to AMCs may threaten their efficacy in the long term. In addition, resistance evolution to AMCs may pose the risk for the development of cross-resistance to antibiotics. The assessment of unacceptable resistance risks during the authorization of AMCs is hampered by the lack of standardized test methods that quantify the adaptability of exposed bacteria to AMCs.
Objectives:
• To develop a standardizable method to determine resistance evolution of bacteria on AMCs (ALEE-AMC)
• To assess performance and robustness of ALEE-AMC in a ring trial
• To uncover the mechanisms underlying evolution of resistance to a metallic copper AMC
• To use ALEE-AMC to assess the evolution of resistance on a novel, nano-particle-based AMC
Methods: ALEE-AMC was developed based on anIntroduction: Antimicrobial surfaces and coatings (AMCs) are important to prevent the spread of pathogens, especially in hygiene-sensitive areas. However, the evolution and selection of bacterial resistance to AMCs may threaten their efficacy in the long term. In addition, resistance evolution to AMCs may pose the risk for the development of cross-resistance to antibiotics. The assessment of unacceptable resistance risks during the authorization of AMCs is hampered by the lack of standardized test methods that quantify the adaptability of exposed bacteria to AMCs.
Objectives:
• To develop a standardizable method to determine resistance evolution of bacteria on AMCs (ALEE-AMC)
• To assess performance and robustness of ALEE-AMC in a ring trial
• To uncover the mechanisms underlying evolution of resistance to a metallic copper AMC
• To use ALEE-AMC to assess the evolution of resistance on a novel, nano-particle-based AMC
Methods: ALEE-AMC was developed based on an international standard to determine the efficacy of antimicrobial surfaces (ISO 22196). In the ALEE-AMC test, adaptive laboratory evolution is conducted by repeated cycles of AMC exposure and re-growth of surviving cells, selecting for increased survival, followed by isolation of evolved clones. Metallic copper was used as a reference AMC and Escherichia coli as a model microorganism in the ring trial. Evolved E. coli populations from the ring trial partners were subjected to phenotypic (antimicrobial susceptibility testing, ISO 22196) and genotypic (whole genome sequencing) characterization. ALEE-AMC will be used to assess the evolution of resistance on a novel, nano-particle-based AMC currently under development.
Findings: The results of the ALEE-AMC ring trial show that repeated exposure to a metallic copper AMC can reproducibly select for reduced copper susceptibility in individual evolutionary lineages across ring trial participants. However, failure to adapt in individual lineages was also observed in all trials. Isolated evolved E. coli clones exhibited increased survival upon exposure to copper surfaces. Adaptation to copper did not induce cross-resistance to antibiotics because the antibiotic susceptibility of copper-adapted clones did not increase above the clinical breakpoint. Whole genome sequencing of the evolved E. coli revealed a high diversity of mutations, including mutations in genes involved in survival to antibiotics. These results indicate the existence of multiple, underexplored evolutionary pathways towards increased survival of antimicrobial copper surfaces.
Conclusion: ALEE-AMC offers a standardizable platform to assess the risk of resistance development towards novel and existing AMCs, including nano-particle-based and metallic copper AMCs. Specifically, using ALEE-AMC provided insights into evolvable survival mechanisms to copper AMCs and its consequences for antimicrobial resistance.…


| Autor*innen: | Niclas NordholtORCiD |
|---|---|
| Koautor*innen: | Selina Schmidt, Viola Boenke, Susann Wiltner, Diana Mogrovejo, Claudia Sündermann, Ina StephanORCiD, Angela Ivask, Merilin Rosenberg, Jan Klock, Florian Brill, Frank SchreiberORCiD, the BioResTest consortium |
| Dokumenttyp: | Posterpräsentation |
| Veröffentlichungsform: | Präsentation |
| Sprache: | Englisch |
| Jahr der Erstveröffentlichung: | 2025 |
| Organisationseinheit der BAM: | 4 Material und Umwelt |
| 4 Material und Umwelt / 4.1 Biologische Materialschädigung und Referenzorganismen | |
| DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Sanitär- und Kommunaltechnik; Umwelttechnik |
| Freie Schlagwörter: | Antimicrobial surfaces; Biocide resistance; Biocides; Evolution; ISO 22196; Standardization |
| Themenfelder/Aktivitätsfelder der BAM: | Umwelt |
| Umwelt / Umwelt-Material-Interaktionen | |
| Veranstaltung: | FEMS MICRO 2025 |
| Veranstaltungsort: | Mailand, Italy |
| Beginndatum der Veranstaltung: | 14.07.2025 |
| Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
| Datum der Freischaltung: | 31.07.2025 |
| Referierte Publikation: | Nein |

