Still Something to Discover: Novel Insights into <i>Escherichia coli</i> Phage Diversity and Taxonomy

• Main Authors: Imke H. E. Korf, Jan P. Meier-Kolthoff, Evelien M. Adriaenssens, Andrew M. Kropinski, Manfred Nimtz, Manfred Rohde, Mark J. van Raaij, Johannes Wittmann
• Format: Article
• Language: English
• Published: MDPI AG 2019-05-01
• Series: Viruses
• Subjects: bacteriophage; <i>Escherichia coli</i>; taxonomy; diversity; genomics
• Online Access: https://www.mdpi.com/1999-4915/11/5/454

The aim of this study was to gain further insight into the diversity of <i>Escherichia coli</i> phages followed by enhanced work on taxonomic issues in that field. Therefore, we present the genomic characterization and taxonomic classification of 50 bacteriophages against <i>E. coli</i> isolated from various sources, such as manure or sewage. All phages were examined for their host range on a set of different <i>E. coli</i> strains, originating, e.g., from human diagnostic laboratories or poultry farms. Transmission electron microscopy revealed a diversity of morphotypes (70% Myo-, 22% Sipho-, and 8% Podoviruses), and genome sequencing resulted in genomes sizes from ~44 to ~370 kb. Annotation and comparison with databases showed similarities in particular to T4- and T5-like phages, but also to less-known groups. Though various phages against <i>E. coli</i> are already described in literature and databases, we still isolated phages that showed no or only few similarities to other phages, namely phages Goslar, PTXU04, and KWBSE43-6. Genome-based phylogeny and classification of the newly isolated phages using VICTOR resulted in the proposal of new genera and led to an enhanced taxonomic classification of <i>E. coli</i> phages.