Whole genome sequencing of TolC-dependent Escherichia phages isolated from poultry
Multidrug-resistant (MDR) avian pathogenic Escherichia coli (APEC) poses a growing threat to poultry production and public health. The outer membrane protein TolC, a key component of the AcrAB-TolC multidrug efflux system, is consistently overexpressed in MDR E. coli field isolates and represents an attractive target for phage-based intervention.This project reports the whole-genome sequencing of two novel TolC-dependent bacteriophages, Escherichia phage vB_EcoM_PTolC28 and Escherichia phage vB_EcoM_PTolC69, isolated from poultry farming environments in Guangdong Province, China, using a purpose-built positive-negative selection strategy. Phage vB_EcoM_PTolC28 was sequenced on the PacBio Sequel platform and assembled de novo into a single circular contig. Sequencing of vB_EcoM_PTolC69 is ongoing and will be deposited under the same BioProject upon completion.Phage vB_EcoM_PTolC28 (148,242 bp; GC 37.48%; 240 predicted ORFs) is phylogenetically related to Enterobacteria phage phi92 within the subfamily Vequintavirinae, and imposes an evolutionary trade-off on its MDR host: phage-resistant mutants exhibit over 60% downregulation of tolC mRNA and collateral resensitization to 12 of 14 tested antibiotics. Phage vB_EcoM_PTolC69 acts through a mechanistically distinct pathway, exhibiting potent phage-antibiotic synergy with doxycycline, amikacin, and florfenicol in vitro, and achieving a 2-4 order-of-magnitude reduction in bacterial burden in a chick infection model when combined with doxycycline.The genome of vB_EcoM_PTolC28 contains no identifiable genes associated with lysogeny, supporting a strictly lytic lifestyle. Raw sequencing reads and annotated genome assemblies are deposited under this BioProject.