Diseño y evaluación de un sistema hibrido de Nanopartículas de plata y Bacteriófagos para la inhibición de Escherichia coli

Abstract

CONDITION FOR PROJECT PUBLICATION. The global rise of antibiotic-resistant bacteria poses a serious public-health challenge. Escherichia coli is among the most pervasive antibiotic-resistant pathogens linked to food- and water-borne outbreaks. Here, a dual antimicrobial system was engineered by combining silver nanoparticles (AgNPs) synthesized through a green route using Psidium guayaquilensis leaf extract with BME3, a lytic myovirus isolated from estuarine water in Guayaquil (Ecuador). AgNPs formation was confirmed by UV–Vis spectroscopy (surface-plasmon peak at 416 nm) and transmission electron microscopy (TEM). Synthesis parameters were optimized through surface-response methodology. Broth macrodilution assays indicated a minimum inhibitory concentration (MIC) of 100 ppm against E. coli. The phage remained fully stable after 48 h of co-incubation with AgNPs at 2 × MIC. A formulation containing 0.5 × MIC AgNPs (50 μg mL⁻¹) and phage at a multiplicity of infection (MOI) of 0.1 completely suppressed bacterial growth within 12 h, whereas either agent alone produced only partial or transient inhibition. Thus, the greensynthesised AgNP–phage system achieves complete bacterial suppression with 50 % less silver, offering a sustainable and highly potent alternative for controlling antibiotic-resistant E. coli infections.