Antibacterial Evaluation of Synthetically Produced Ionic Liquids for Its Potential Therapeutic Use against Uropathogenic Escherichia coli (UPEC)

Abstract

In recent decades, the emergence of multi-drug resistant (MDR) pathogens has rapidly escalated. To overcome the threat of antimicrobial resistance (AMR), it is important to synthesize new biologically effective compounds such as ionic liquids (ILs) to contain the bacterial infection and their spread. Ionic liquids are poorly coordinated organic salts characterized by melting points typically below 100 °C ILs versatility in terms of anionic and cationic combinations allows for a wide range of chemical, physical and biological properties. In the present study, a total of 9 previously chemically synthesized and characterized ILs were used. For exploration of their antibacterial potential against the urinary tract infections (UTIs) caused by MDR Uropathogenic Escherichia coli (UPEC) strains, in vitro and in vivo evaluation of ILs were performed. The antibacterial activities of ILs showed maximum zone of inhibition (ZOI) of 29.5mm, the minimum inhibitory concentration (MIC) of 3.81μM, minimum bactericidal concentration (MBC) of 5.08μM by agar disk diffusion and broth micro-dilution methods, respectively. In addition, these ILs showed significant morphological changes in UPEC biofilm formation characterized by scanning electron microscopy (SEM). To further elucidate efficacy, antioxidant potential of ILs was also explored with the highest of 22.05%. ILs had low cytotoxic effect toward mammalian cell lines (NB4), red blood cells (RBCs) and whole blood. Moreover, the RT-qPCR gene expression analysis results justified the antibacterial potential of ILs showing down-regulation of fimH, uvrY and up-regulation of csrA gene in UPEC after ILs treatment. In vivo trials for dermal sensitivity also showed no cytotoxicity towards skin cells. In conclusion, the ILs exhibiting strong antibacterial and antioxidant potential with less cytotoxicity and safety towards body cells could be an alternative for the treatment of UTIs