Antibiofilm and antibacterial activities of repurposing auranofin against Bacteroides fragilis
The aim of this study is to evaluate the antibiofilm and antibacterial effects of auranofin against WT-ETBF, rETBF, WT-NTBF and clinically isolated Bacteroides fragilis strains. The minimum inhibitory concentration and biofilm inhibitory concentration of 0.25 μg/ml for auranofin against B. fragilis were determined, and the biofilm eradication concentration was 1 μg/ml. At an auranofin concentration of 0.5 μg/ml, little cellular metabolic activity was found. Confocal laser scanning microcopy results confirmed the inhibition of biofilm by auranofin. The effects of auranofin on the outer membrane protein (ompA) gene and the RND-type efflux pump (bmeB3) gene were investigated using quantitative real-time polymerase chain reaction (qRT-PCR). The qRT-PCR results showed that treatment with auranofin significantly reduced the gene expression compared to controls without auranofin. These data indicate the applicability of auranofin as a repurposed drug due to its inhibitory effect against biofilm formation of B. fragilis. Therefore, our study demonstrates that auranofin, already approved for human use, is a promising drug that has strong antibiofilm and antibacterial activity against B. fragilis.
KeywordsBacteroides fragilis Auranofin Antibiofilm Antibacterial ompA gene bmeB3 gene
This research was supported by Soonchunhyang University Research Fund (Grant no. 20190911) and a Grant (NRF-2017R1D1A1B03032960) of the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education.
Authors declare that all listed authors have made substantial contributions to the research design, or the acquisition, analysis or interpretation of data, and to drafting the paper or revising it critically; and that all authors have approved the submitted version. Authors also declare that nobody who qualifies for authorship has been excluded from the list of authors.
Compliance with ethical standards
Conflict of interest
All authors declare they have no conflict of interest relevant to this article.
- Clinical and Laboratory Standards Institute (CLSI) (2018) Methods for antimicrobial susceptibility testing of anaerobic bacteria, 9th edn. CLSI, Wayne, p M11Google Scholar
- Kato N et al (2000) A new subtype of the metalloprotease toxin gene and the incidence of the three bft subtypes among Bacteroides fragilis isolates in Japan. FEMS Microbiol Lett 182:171–176. https://doi.org/10.1111/j.1574-6968.2000.tb08892.x CrossRefPubMedGoogle Scholar
- Woo SG et al (2017) The effectiveness of anti-biofilm and anti-virulence properties of dihydrocelastrol and dihydrocelastryl diacetate in fighting against methicillin-resistant Staphylococcus aureus. Arch Microbiol 199:1151–1163. https://doi.org/10.1007/s00203-017-1386-x CrossRefPubMedGoogle Scholar