Inhibition of Staphylococcus Aureus and Biofilm Formation by the Anthelminthic Drug, Triclabendazole

Triclabendazole (TBD) has been widely used in the treatment of helminthic infection. The anti-biofilm activity and antibacterial mechanism of TBD against Staphylococcus aureus were not known. Here, the anti-biofilm activity of TBD against clinical S. aureus isolates from China was systematically evaluated. Under TBD pressure, TBD-induced tolerant S. aureus with elevated TBD minimum inhibitory concentration (MIC) was selected in vitro and the genetic mutations between the parental isolates and TBD-induced tolerant derivatives were determined by whole-genome sequencing. TBD could significantly inhibit biofilm formation at sub-inhibitory concentration and disperse mature biofilm of clinical S. aureus isolates. In addition, TBD displayed bactericidal activity against the bacterial cells embedded in the biofilm and showed anti-persisters activity. Proteomic analysis showed that KEGG pathways of ABC transporters and beta-lactam resistance were significantly changed after TBD exposure. Moreover, SAUSA300_RS08395 (molecular chaperone DnaK), SAUSA300_RS11200 (sensor histidine kinase KdpD), SAUSA300_RS06325 (DNA translocase FtsK) were identified as candidate targets of TBD in S. aureus . Overexpression experiments further demonstrated that the elevated transcriptional level of DnaK resulted in S. aureus growth delay after exposure to a sub-MIC concentration of 1/2× MIC TBD. In conclusion, TBD exhibits antibacterial and anti-biofilm activity against S. aureus possibly by targeting the DnaK chaperone system.