Diseño de cócteles de bacteriófagos con sinergia lítica y estabilidad funcional para el control de Salmonella enterica serovar Infantis de origen avícola ecuatoriano

Abstract

This study presents a comprehensive approach for the rational design of bacteriophage cocktails aimed at controlling Salmonella enterica serovar Infantis, a pathogen of increasing public health concern within the Ecuadorian poultry industry. Using an initial collection of lytic phages isolated in the country, we conducted an exhaustive characterization of their lytic spectra, bactericidal activity, and functional stability under conditions simulating poultry processing environments, including refrigeration and exposure to controlled chlorine concentrations. This analysis enabled the identification of phages with robust performance, as well as the exclusion of those exhibiting limited or unstable activity. Subsequently, experimental combinations were assessed to determine phage compatibility, distinguishing synergistic interactions from antagonistic effects that could compromise cocktail efficacy. The selected mixtures demonstrated complementary lytic activity, expanded host range coverage, and consistent stability under the operational conditions evaluated. The formulation process was supported by multifactorial statistical modeling and estimated marginal means analyses, ensuring that the final selection was guided by quantitative and reproducible criteria. Overall, the findings demonstrate the feasibility of developing phage cocktails with strong potential for implementation in microbiological control programs within the poultry production chain. This study provides evidence supporting the use of phages as a biotechnological alternative against multidrug-resistant S. Infantis and establishes a solid foundation for subsequent efficacy assessments in meat matrices and real production systems, ultimately contributing to enhanced food safety and mitigation of risks associated with emerging pathogens in Ecuador.