Agtrevirus Phage AV101 Recognizes Four Different O-antigens Infecting Diverse

Bacteriophages in the genus are known for expressing multiple tail spike proteins (TSPs), but little is known about their genetic diversity and host recognition apart from their ability to infect diverse species. Here, we aim to determine the genetic differences that may account for the diverse host ranges of phages. We performed comparative genomics of 14 and identified only a few genetic differences including genes involved in nucleotide metabolism. Most notably was the diversity of the gene cluster, specifically in the receptor-binding domains that were unique among most of the phages. We further characterized agtrevirus AV101 infecting nine diverse Extended Spectrum β-lactamase (ESBL) and demonstrated that this phage encoded four unique TSPs among . Purified TSPs formed translucent zones and inhibited AV101 infection of specific hosts, demonstrating that TSP1, TSP2, TSP3, and TSP4 recognize O8, O82, O153, and O159 O-antigens of , respectively. BLASTp analysis showed that the receptor-binding domain of TSP1, TSP2, TSP3, and TSP4 are similar to TSPs encoded by prophages and distant related virulent phages. Thus, may have gained their receptor-binding domains by recombining with prophages or virulent phages. Overall, combining bioinformatic and biological data expands the understanding of TSP host recognition of and give new insight into the origin and acquisition of receptor-binding domains of phages.