Genomic and in vitro characterization of two lytic bacteriophages infecting multidrug-resistant Erwinia sp. strain AnSW2-5

Abstract

Abstract Multidrug-resistant (MDR) Erwinia pathogens present a critical threat to global crop health and agricultural sustainability. In this study, we characterized two novel lytic bacteriophages, AnSW2-5-P-A (family Autographiviridae ) and AnSW2-5-P-K (class Caudoviricetes ), targeting the MDR Erwinia sp. strain AnSW2-5. Comparative genomics and TEM analysis revealed distinct virion architectures and confirmed the absence of lysogeny-associated genes, ensuring their safety as biocontrol agents. One-step growth assays demonstrated that P-A has a shorter latent period (~ 20 min), while P-K exhibits a significantly larger burst size (~ 110 PFU/cell). In co-culture assays, the dual-phage cocktail demonstrated a profound synergistic effect, achieving > 80% bacterial reduction ( p  < 0.05) and maintaining sustained suppression of the host for 72 h. Notably, the cocktail effectively prevented the emergence of resistant mutants, reducing the frequency of resistance ( FoR ) to below the limit of detection (< 10⁻⁸). These findings highlight the potential of using genetically diverse phage pairs with complementary lytic activities as a robust, resistance-suppressive biocontrol strategy against MDR phytopathogens.