Anti-psychotic drug thioridazine acts as a potent anti-microbial agent for multidrug-resistant bacteria: a clinical strains-based study

Abstract

Abstract Background Multidrug-resistant (MDR) bacteria emerge as a public health problem worldwide. The aim of this study was to investigate the effect of thioridazine on multidrug-resistant (MDR) clinical isolated strains and to provide new strategies for the treatment of MDR infections. Methods Bacteria were isolated from the clinical patients. The identification and susceptibility testing of the isolated strains were completed by MALDI-TOF mass spectrometry and the VITEK 2 Compact analysis system, respectively. The antibacterial efficacy of thioridazine in vitro was assessed using the agar dilution method. Results A total of 156 strains were isolated from the clinical patients. Among these strains, MRSA, MDR Enterococcus, and MDR Acinetobacter baumannii were significantly inhibited by low concentration of thioridazine (20 µM). Susceptible Acinetobacter baumannii and Stenotrophomonas maltophilia were inhibited by thioridazine at intermediate concentrations (40 µM). Pseudomonas aeruginosa, Klebsiella pneumoniae, and MDR Escherichia coli were inhibited by high concentrations of thioridazine (100 µM). Conclusions Thioridazine could be repurposed as an agent against a variety of MDR bacteria.