One-pot synthesis of a new magnetic disinfectant was achieved through the polymerization of thiourea and formaldehyde in the presence of magnetite nanoparticles (MTUF). The obtained magnetic chelating resin was loaded with Ag(I) ions. This material was tested as a disinfectant for water pathogenic microorganism's deactivation. The toxicity of MTUF before and after Ag(I) loading was estimated. The antimicrobial activity tests of MTUF-Ag were carried out against Escherichia coli, Salmonella Typhimurium, and Pseudomonas aeruginosa as examples of Gram-negative bacteria; Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis, and Bacillus subtilis as examples of Gram-positive bacteria; and Candida albicans as representative for fungi. The results showed that the minimum inhibitory dosage (MID) of MTF-Ag against Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and mixed culture were 1.5, 2.0, 1.0, 1.5, and 1.5 mg/mL, respectively, after 40 min of contact time. While C. albicans was more resistant to the magnetic disinfectant, only three log reductions were done at 2.5 mg/mL. The studied MTUF-Ag was successfully tested for water and wastewater pathogenic microorganism's deactivation. It can be concluded that MTUF-Ag could be a good candidate for water disinfection.

Cymbopogon citratus is grown globally for therapeutic application is utilized to synthesize colloidal silver nanoparticles (CcAgNps). CcAgNps are characterized by biophysical methods and are tested against CTXM-15 expressing pathogenic Escherichia coli strains. MIC, MBC and biofilm assays are performed at different concentrations of nanoparticles. The expression of CTXM-15 gene responsible for antibiotic resistance is analyzed by polymerase chain reaction to identify the role of CTXM-15 in pathogenesis. CcAgNps show better antibacterial and anti-biofilm activity when compared to antibiotics. This study suggests that CcAgNps are the potential antibiotic resistance breakers to control pathogenic E. coli and can be utilized as alternatives to antibiotics.

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