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Aim Polymicrobial biofilm encasing cross-kingdom micro-organisms are apparent in medicine, which imposes serious resistance to conventional antimicrobial treatment. The objective of the study was to explore Butea monosperma seed lectin (BMSL) conjugated antimicrobial lipid, 2-((N-[2-hydroxyethyl]palmitamido)methyl)-1-methylpyridin-1-ium iodide (cN16E) to inhibit mixed-species biofilm of uropathogenic Escherichia coli–Candida albicans. Methods and Results Antimicrobial activity and antibiofilm of cN16E and cN16E-BMSL conjugate (BcN16E) were analysed against single- and mixed microbial cultures. The minimum inhibitory concentration (MIC) indicates that the MIC of cN16E-BMSL conjugate (BcN16E) against cohabiting UPEC-C. albicans was eightfold lower than the cN16E. BcN16E affects membrane integrity to elicit antimicrobial activity. BcN16E inhibits the dual-species biofilm even with 16 times lower MIC of cN16E. BcN16E impairs the biofilm-associated virulence factors which include extracellular polysaccharides, cell surface hydrophobicity, swimming, swarming motilities, hyphal filamentous morphology, curli formation and haemolysin activity. As a proof of concept, we demonstrated BcN16E ability to inhibit dual-species biofilm formation on a urinary catheter. Conclusion The study revealed that the BcN16E is better than cN16E in impairing biofilm-associated virulence factors and exerting antimicrobial activity. Significance and Impact of the Study The findings emphasize that phytolectin has the potential to enhance the anti-virulence strategies of antimicrobials against cross-kingdom biofilm-related infections.

Herein, cationic antimicrobial lipid, [2-((N-(2-hydroxyethyl)palmitamido)methyl)-1-methylpyridin-1-ium iodide], (cN16E) was reported for the first time as stabilizing agent in the preparation of copper sulfide nanoparticles (cN16E-CuS). X-ray photoelectron spectroscopy confirmed the formation of cN16E-CuS, and FTIR analysis revealed that the NPs were stabilized by cN16E. Transmission electron microscopy imaging showed that the NPs are in the size range from 6 to 8 nm. The cN16E-CuS exhibit excellent antimicrobial activity against Carbapenem-Resistant Acinetobacter baumannii with a MIC of 62.5 µM, which is two-fold lower than the MIC of pure cN16E. Mechanistic study showed that pure cN16E damages bacterial membranes, whereas cN16E-CuS produces additional effect through producing excess reactive oxygen species and exhibit superior antimicrobial activity at lower concentration.