Synthesis and evaluation of inhibitory potentials of microbial biofilms and quorum-sensing by 3-(1,3-dithian-2-ylidene) pentane-2,4-dione and ethyl-2-cyano-2-(1,3-dithian-2-ylidene) acetate

Abstract

The virulence and resistance of pathogenic microorganisms are promoted by quorum-sensing (QS) mediated traits and biofilms. The development of antimicrobial agents which can reduce the incidence of microbial resistance by disrupting the establishment of biofilms and QS, constitute a suitable strategy to reduce the emergence of pathogenic strains that are resistant to antibiotics. In this study, 3-(1,3-dithian-2-ylidene) pentane-2,4-dione (1) and ethyl-2-cyano-2-(1,3-dithian-2-ylidene) acetate (2) were successfully synthesized and characterized using EIMS, 1H NMR and 13C NMR techniques. On S. aureus, both compounds had MIC (minimal inhibitory concentrations) of 0.625 mg/mL while on E. coli and C. albicans, compound 2 showed higher activity than compound 1. All compounds inhibited formation of biofilms by C. albicans and S. aureus at sub-MIC with compound 1 being more active than compound 2. On E. coli, only compound 1 inhibited biofilm formation. Violacein production of violacein in C. violaceum CV12472 and quorum sensing in C. violaceum CV026 were inhibited indicating that the compounds could block signal production and reception. Anti-quorum sensing at sub-MIC concentrations revealed by inhibition zones were 13.0±0.5 mm and 8.0±0.5 mm at MIC and MIC/2 respectively for compound 1 and for compound 2, they were 11.5±0.4 mm and 7.5±0.0 mm at MIC and MIC/2 respectively. Concentration-dependent swarming motility was exhibited by both compounds with compound 1 slightly more active than compound 2. The results indicate that the organosulphur compounds could be suitable candidates for modern antibiotics.

Synthesis of cross‐linked diazaborine‐based polymeric microparticles with antiquorum sensing, anti‐swarming, antimicrobial, and antibiofilm properties

“…The antibiofilm effects of the polymers at MIC and sub‐MIC concentrations (1, 1/2, 1/4, and 1/8 MIC) on test pathogens were evaluated using a microplate biofilm method 32 . One percent of overnight bacterial cultures were introduced into 200 μl of Tryptose‐Soy Broth (TSB) containing 0.25% of glucose and with or without the test polymers and incubated at 37°C for 48 h and then wells of the plates were carefully emptied and rinsed with distilled water so as to remove the planktonic microbial cells.…”

Synthesis of a new diarylhydrazone derivative and an evaluation of its in vitro biofilm inhibition and quorum sensing disruption along with a molecular docking study

“…Resistance to antibiotics by pathogenic bacteria occurs when bacteria acquire the ability to overcome the effects of antibiotics that were used previously to inhibit them. 10,11 Antimicrobial resistance is an emerging worldwide health challenge, causing morbidities and mortalities even in hospital settings. Despite the development of conventional antimicrobials as solutions, there is a multidrug-resistant pattern in Gram-positive and Gram-negative bacteria, as well as in fungi, resulting in difficult-to-treat or even untreatable infections.…”

“…16 Microbial pathogens can evolve and develop resistance, usually aided by quorum sensing (QS)-mediated virulence factors and biofilm formation, and this requires a multidisciplinary approach involving antimicrobial molecules of synthetic and natural origin that can act on the pathogens by various mechanisms involving biofilms and QS. 11,17,18 Bacterial biofilms are aggregates of bacterial cells attached to a surface and coated with a polymeric layer. [19][20][21] They protect bacteria and allow them to survive in harsh environmental conditions.…”

Inhibition of biofilm, quorum‐sensing, and swarming motility in pathogenic bacteria by magnetite, manganese ferrite, and nickel ferrite nanoparticles

“…6 Antimicrobials with new modes of action, capable of inhibiting growth, reproduction, and spread of pathogenic microbes by disrupting quorum sensing (QS) microbial cell-to-cell communication networks, biofilm formation, coordinated behavior, and movement are most sorted strategic antimicrobial therapies from both natural and synthetic compounds. [7][8][9][10][11][12][13] A biofilm consists of a protective shield within which bacteria survival is greatly enhanced even in drought, starvation, and the presence of antibiotics. The inhibition of the set of virulence factors mentioned before is referred to as quorum quenching that could involve the degradation of signal molecules used by microorganisms to coordinate behavior within colonies, which has attracted much attention.…”

“…Most of the antimicrobials act on specific pathogen types with a more or less action on other types and generally are applied as antibiotics, antifungals, anti‐helminthics, and antiseptics 6 . Antimicrobials with new modes of action, capable of inhibiting growth, reproduction, and spread of pathogenic microbes by disrupting quorum sensing (QS) microbial cell‐to‐cell communication networks, biofilm formation, coordinated behavior, and movement are most sorted strategic antimicrobial therapies from both natural and synthetic compounds 7–13 . A biofilm consists of a protective shield within which bacteria survival is greatly enhanced even in drought, starvation, and the presence of antibiotics.…”