Desarrollo de un cóctel de bacteriófagos líticos para el biocontrol de escherichia coli presente en aguas residuales de una planta de tratamiento

Abstract

The reuse of treated wastewater represents a key strategy to mitigate water scarcity; however, the persistence of Escherichia coli strains resistant to intensive disinfection processes poses a risk to both public health and the environment. This study evaluates the efficacy of a lytic bacteriophage cocktail for controlling resistant E. coli strains in wastewater. The cocktail was formulated by combining two previously characterized phages with a newly isolated broad-lytic-spectrum phage obtained from wastewater samples collected at the treatment plant of the Escuela Superior Politécnica del Litoral. Its effectiveness was assessed through laboratory bioassays and statistical analysis using a t-test with a 95% confidence level. The results demonstrated a 100% elimination of E. coli after 18 h of exposure, with significant differences between treated replicates (R1 and R2) and the negative control (C⁻) (R1 vs C⁻: p = 0.0298; R2 vs C⁻: p = 0.01682), and no relevant differences between replicates (p = 0.73). These findings suggest that phage cocktails are a promising alternative to enhance the microbiological quality of treated wastewater and promote its safe reuse. Keywords: Wastewater reuse, Escherichia coli, lytic bacteriophages, phage cocktail, antimicrobial resistance.