Nanoformulation target virulence genes to break antibiotic resistance in MDR E. coli

Bacterial infection causes a large impact on the health of humans, animals, plants, and marine organisms. The infection caused by bacteria can be cured with the usage of prescribed antibiotics. However, inappropriate consumption of antibiotics leads to the raise of more antibiotic-resistant strains. For the past few decades, antimicrobial resistance has been considered a global health problem. One of the most common Gram-negative species is Escherichia coli, causing several infections in all living forms. During the last few decades, extended-spectrum beta-lactamases (ESBL) producers involved in the spread of drug resistance genes and cause several diseases. Therefore, it is important to choose an ecofriendly alternative to control infections caused by multidrug-resistant, biofilm-forming E. coli. Green silver nanoparticles with unique properties are reported to show superior antimicrobial and antibiofilm activity. Hence, this paper focuses on evaluating the antibacterial potential of polyherbal nanoformulation (PHNF) against Escherichia coli strains isolated from human samples through various antimicrobial assays and Cefotaximase-Munich (CTX-M-15) gene expression studies. The results of agar well-diffusion method suggest enhanced antibacterial activity even at a very low concentration of PHNF. MIC concentration was found as 0.78 μg/ml in EC ATCC (25,922), 1.56 μg/ml for EC 13, and EC 36, 0.78 μg/ml for in EC 36, and EC 3 T. MBC was found as 0.78 μg /ml in EC ATCC (25,922), 3.125 μg/ml for EC 13, 6.25 μg/ml for EC 16, 0.78 μg /ml for EC 36, and 1.56 μg/ml for EC 3 T. Upon treatment with PHNF at their MIC concentration, the formation of biofilm in E. coli strains was reduced in all the EC strains. PHNF treatment in EC strains suppressed CTX-M-15 gene at minimum bacteriostatic concentration, but not in the ampicillin treatment. The results upon PHNF treatment were very promising by showing bacteriostatic, bactericidal, and antibiofilm property. Moreover, the CTX-M-15 gene was also abolished completely upon treatment with PHNF. This confirms the potential of PHNF as potent antibacterial agent. To the best of our knowledge, this is the first report on novel polyherbal nanoformulation known to inhibit the growth, biofilm formation, and interference with the CTX-M-15 gene in tested strains of Escherichia coli. The principle of synergism works very well, both in the preparation of the PHNF and also exhibiting its potent function without harming the living beings in the environment. © 2023, King Abdulaziz City for Science and Technology.