Antimicrobial and antibiofilm activities of 1-alkylquinolinium bromide ionic liquids

Abstract

Quinoline derivatives are known to possess a range of bioactive and medicinal activities, which have been exploited in the design of antibacterial, antifungal and antimalarial compounds. In this study, we report on the microbiological toxicity of a series of 1-alkylquinolinium bromides against a range of clinically relevant microorganisms, in both planktonic and sessile (biofilm) cultures. A comparison of antimicrobial activity against planktonic bacteria and established biofilms is presented. In general, 1-alkylquinolinium ionic liquids possess excellent, broad spectrum antimicrobial activity against microorganisms grown in both the planktonic and sessile, or biofilm, mode of growth. Importantly, these compounds are potent against Gram positive and Gram negative bacteria, as well as fungi, with a clear dependency on length of the alkyl substituent for activity, with compounds containing twelve and fourteen carbons in the alkyl group exhibiting highest antimicrobial and antibiofilm activity.

Antimicrobial Ionic Liquids

“…The data from this study indicate that Gram positive microbial biofilms (in keeping with planktonic cultures) are generally more susceptible to 1-alkylmethylimidazolium ionic liquids than Gram negative bacterial biofilms, whilst Candida tropicalis biofilms exhibited a similar susceptibility profile to these reagents as the representative Gram positive organisms tested in this study (Carson et al, 2009). In a further study from the same group, Busetti and co-workers, described the antimicrobial and antibiofilm activities of a range of 1-alkylquinolinium bromide ionic liquids (Busetti et al, 2010). In general, these ionic liquids are the most potent antibiofilm ionic liquids tested so far, having a superior microbiological toxicity to the 1-alkyl-3-methylimidazolium ionic liquids against both planktonic and biofilm cultures of a range of bacteria and fungi commonly implicated in nosocomial and device associated infections, including Staphylococcus epidermidis, Pseudomonas aeruginosa, Klebsiella aerogenes and Bacillus cereus.…”

“…Whilst the majority of these tests have relied on basic planktonic susceptibility assays (minimum inhibitory concentrations (MIC) or minimum bactericidal/fungicidal concentration (MBC/MFC)) or agar diffusion techniques, the importance of evaluation of antimicrobial activity against microbial biofilms is also discussed. In our group, we have pioneered the use of high throughput screening of ionic liquids against clinically relevant microorganisms grown as biofilms, by determination of minimum biofilm eradication concentration (MBEC) (Carson et al, 2009;Busetti et al, 2010).…”

Ionic Liquids: Future Solvents and Reagents for Pharmaceuticals

“…In fact, this property allows for appropriate design of ILs that could be used as new and improved antiseptics, disinfectants and anti-fouling reagents. To date, a number of publications have highlighted the antimicrobial activity of imidazolium, pyridinium and quaternary ammonium ILs against both environmental and clinically important micro-organism (Pernak et al, 2003(Pernak et al, , 2004b(Pernak et al, , 2004cPernak and Feder-Kubis, 2005;Docherty and Kulpa, 2005;Carson et al, 2009;Hough-Troutman et al, 2009;Busetti et al, 2010). For example, Pernak and co-workers evaluated the antimicrobial activity of a series of 3-alkoxymethyl-1-methylimidazolium ILs with different anions, (Pernak et al, 2003) 1,3-(dialkyloxymethyl)-substituted imidazolium ILs with different anions (Pernak et al, 2004b) and 1-alkylimidazolium and 1-alkoxymethyl-imidazolium protic ILs with lactate anion (Pernak et al, 2004c) against clinically significant pathogens (rods, cocci and fungi).…”

Antimicrobial Activity of 1,3 Dihydroxy-2-Methylimidazolium Bis (Trifluoromethylsulfonyl) Imde and Selected Antibiotics Against <i>Streptococcus</i> Species Isolated from Groundwater in the Northwest Province, South Africa

“…Due to their unique properties ILs are very useful in both the chemical and biological industries and also serve as successful replacements for some organic solvents used in synthetic [20,21] separation and extraction processes [22,23]. Given their environmental advantage and the fact that some ILs have been shown to possess antimicrobial activities [15,16,17] we evaluated the effect of 1,3-dihydroxy-2-methylimidazolium bis (trifluoromethylsulfonyl) imide on streptococci isolated from groundwater. 1,3-dihydroxy-2-methylimidazolium bis (trifluoromethylsulfonyl) imide is an ionic liquid with a molecular weight of 409.28 and it is used as an Nheterocyclic carbene (NHC) precatalyst.…”

“…Ionic liquids are basically salts that are in the liquid phase below 200°C [14]. Ionic liquids (ILs) are attracting increasing attention worldwide due to their unique properties, which include negligible vapor pressure, chemical and thermal stability, non-flammability, high ionic conductivity, low melting points, low viscosity, wide electrochemical potential window, solvation ability and antimicrobial activity [15,16,17,18]. ILs have been shown to exhibit antimicrobial activities against cocci, rods and fungi and there is usually a correlation between the structure of the cation and the antimicrobial activity of the solvent [19].…”