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Replication Region Analysis Reveals Non-lambdoid Shiga Toxin Converting Bacteriophages
Ann-Katrin Llarena1, Marina Aspholm1, Kristin O'Sullivan1
1Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway.
Frontiers in Microbiology
|April 19, 2021
Summary
New Shiga toxin-converting phage (Stx phage) replication genes, termed eru genes, were identified in non-lambdoid phages. Eru1-phages, linked to severe outbreaks, show less stable lysogeny, potentially increasing virulence in enterohemorrhagic Escherichia coli (EHEC).
Area of Science:
- Microbiology
- Virology
- Genetics
Background:
- Shiga toxin-converting phages (Stx phages) are key virulence factors in enterohemorrhagic Escherichia coli (EHEC).
- Stx phages are typically classified as lambdoid phages, sharing genetic and lifestyle similarities with lambda phages.
- Lambdoid phages initiate replication via O and P genes, which are absent in some non-lambdoid Stx phages.
Purpose of the Study:
- To investigate the replication mechanisms of non-lambdoid Stx phages.
- To characterize novel replication genes in Stx phages lacking lambdoid O and P genes.
- To explore the implications of different Stx phage replication types on EHEC virulence and classification.
Main Methods:
- Genomic analysis of Stx phages to identify replication genes.
- Classification of Stx phages based on identified replication regions (Eru-phages).
- Comparative analysis of lysogenic stability between different Stx phage types.
Main Results:
- Identification of novel replication genes, named eru genes, in non-lambdoid Stx phages.
- Classification of these phages into three types: Eru1, Eru2, and Eru3.
- Eru1-phages, found in highly pathogenic EHEC strains from major outbreaks (Norway 2006, Europe 2011), demonstrated less stable lysogeny compared to lambdoid Stx phages.
Conclusions:
- The replication region is a crucial factor for Stx phage classification, alongside Stx-type.
- Eru1-phages, due to their less stable lysogenic state, may contribute to a high-virulence phenotype in EHEC.
- Classifying Stx phages by replication regions can aid in identifying highly virulent EHEC strains for improved risk assessment and management.
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