Aims: This study was performed to identify the potential for repurposing auranofin as an antibiotic adjuvant against carbapenemase-producing Acinetobacter baumannii.
Methods and results: The clinically isolated A. baumannii strains used in this study were all resistant to carbapenems and harboured the blaOXA-23 gene. The synergistic effect of auranofin and doripenem against carbapenemase-producing A. baumannii was confirmed through checkerboard and growth kinetic analyses. This study also demonstrated the inhibitory effects of auranofin against A. baumannii biofilms. The anti-biofilm effects of auranofin were visualized by confocal laser scanning microscopy (CLSM). Furthermore, auranofin inhibited motility, one of the virulence factors. Additionally, the changes in the expression of carbapenemase-, biofilm- and efflux pump-related genes induced by auranofin were confirmed via quantitative polymerase chain reaction (qPCR).
Conclusions: Our results demonstrated that auranofin has an antibacterial effect with doripenem and an inhibitory effect on several factors related to carbapenem resistance.
Significance and impact of the study: This study suggests that auranofin is a promising antibiotic adjuvant that can be used to prevent antibiotic resistance in carbapenem-resistant A. baumannii.
Keywords: A. baumannii; anti-biofilm; auranofin; carbapenem; carbapenemase; synergistic activity.
© 2022 Society for Applied Microbiology.