Ionic gold demonstrates antimicrobial activity against Pseudomonas aeruginosa strains due to cellular ultrastructure damage

Miguel Reyes Torres, Anthony J Slate, Steven F Ryder, Maliha Akram, Conrado Javier Carrascosa Iruzubieta, Kathryn A Whitehead

Research output: Contribution to journalArticlepeer-review

14 Citations (SciVal)


Due to the ever-increasing rise of antimicrobial resistant (AMR) bacteria, the development of alternative antimicrobial agents is a global priority. The antimicrobial activity of ionic gold was explored against four Pseudomonas aeruginosa strains with different AMR profiles in order to determine the antimicrobial activity of ionic gold and elucidate the mechanisms of action. Disc diffusion assays (zone of inhibition: ZoI) coupled with minimum inhibitory/bactericidal concentrations (MIC/MBC) were conducted to determine the antimicrobial efficacy of ionic gold. Scanning electron microscopy (SEM) was used to visualise morphological changes to the bacterial cell ultrastructure. Strains with increased AMR were slower to grow which is likely a fitness cost due to the enhanced AMR activity. Although greater concentrations of ionic gold were required to promote antimicrobial activity, ionic gold demonstrated similar antimicrobial values against all strains tested. Lowry assay results indicated that protein leakage was apparent following incubation with ionic gold, whilst SEM revealed cellular ultrastructure damage. This study suggests that the application of ionic gold as an alternative antimicrobial is promising, particularly against AMR P. aeruginosa. The antimicrobial activity of ionic gold against P. aeruginosa could potentially be utilised as an alternative therapeutic option in wound management, an approach that could benefit healthcare systems worldwide.

Original languageEnglish
Pages (from-to)3015-3024
Number of pages10
JournalArchives of Microbiology
Issue number6
Early online date29 Mar 2021
Publication statusPublished - 31 Aug 2021

Bibliographical note

Funding Information:
The authors would like to thank Dr. Jonathan A. Butler and Dr. Maria Jose Huertas Romera for providing useful discussions and insights?regarding antimicrobial activity evaluation.

Publisher Copyright:
© 2021, The Author(s).


  • Antimicrobials
  • Ionic gold
  • Mechanism of action
  • Metals
  • Pseudomonas aeruginosa
  • Resistance

ASJC Scopus subject areas

  • Microbiology
  • Biochemistry
  • Molecular Biology
  • Genetics


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