The small genome, virulent, non-contractile tailed bacteriophages that infect Enterobacteriales hosts

Tailed bacteriophages are abundant and extremely diverse. Understanding this diversity is a challenge, and here we examine a small slice of that diversity in some detail. We contrast and compare the small genome, virulent, non-contractile tailed phages that infect the bacterial order Enterobacteriales. These phages, with genomes in the 35–60 kbp range, have very similar virions that are often difficult to distinguish by negative stain electron microscopy. There are currently 651 genome sequences of such phages in the public database. We show that these can be robustly parsed into fifteen well-defined clusters that have very different nucleotide sequences. We examine the similarities and differences among these clusters, as well as genetic exchange among clusters and the relationships between host species and phage clusters. •We analyze the currently available 651 genomes of small genome, virulent, non-contractile tailed phages that infect the bacterial order Enterobacteriales (SVNT-E phages).•The genomes of these phages can be robustly parsed into fifteen well-defined types or clusters.•The cognate virion structural proteins of these phages are very diverse in amino acid sequence but are largely homologous across all fifteen clusters.•Within clusters these phages generally group according to the host genus.