Ionic liquids and organic salts with antimicrobial activity as a strategy against resistant microorganisms

Antimicrobial resistance (AMR) is a subject of growing concern facing humanity caused mainly by the overuse and misuse of antimicrobials, lack of adherence to antimicrobial regimens and therapies, and the limited quantities of novel drugs being developed to substitute the ones that have become ineffective. Besides death and disability, severe illness causes prolonged hospital stays and, consequently, financial challenges for those involved, with its overall economic cost being significant. Inadequate conditions such as the absence of clean water, sanitation, and prevention and control protocols further advance the spread of pathogens which may be resistant to treatment. Without effective antimicrobials, the success of modern medicine in treating infections caused by drug-resistant pathogens would be at increased risk. Strategies to fight AMR include the synthesis, characterization, and evaluation of new compounds using new approaches such as combination drug antibiotic adjuvant therapy. Adjuvants can improve the action of already approved antibacterial drugs towards multidrug-resistant bacteria either by decreasing the impact and appearance of resistance or enhancing the antibacterial effect. Literature also supports the use of ionic liquids (ILs) and a group of uniform materials based on solid salts (GUMBOS) as alternatives that may solve some problems posed by traditional combination therapies. They allow changes in chemical structures to be investigated as an alternative therapy composed of a single molecule, instead of several unreacted moieties. For the last decade, ionic liquids and organic salts from active pharmaceutical ingredients have been studied at the AMR panorama, exhibiting a strong broad spectrum activity towards several resistant bacterial strains. Cations commonly used in ILs are based on imidazolium, ammonium, benzalkonium, benzethonium, phosphonium, pyridinium, pyrrolidinium, piperidinium, piperazinium, azepanium, morpholinium, quinolinium, 1-10-phenanthrolinium, guanidinium, cholinium, commercial antibacterials and antiseptics. Another revolutionary therapy to combat AMR is nanotechnology which can control and alter molecular structures at the nano dimension to obtain specific target action. Besides IL-assisted nanoparticles with antimicrobial properties, there is a new category of nanoGUMBOS derived from organic salts still being investigated that has presented interesting potential as a new strategy for AMR as they present morphological, spectral, and surface charge tunability associated with different cation-anion combinations. (c) 2022 Elsevier B.V. All rights reserved.