Comparative genomics of Shiga toxin encoding bacteriophages

• Main Authors: Smith Darren L, Rooks David J, Fogg Paul CM, Darby Alistair C, Thomson Nick R, McCarthy Alan J, Allison Heather E
• Format: Article
• Language: English
• Published: BMC 2012-07-01
• Series: BMC Genomics
• Online Access: http://www.biomedcentral.com/1471-2164/13/311

<p>Abstract</p> <p>Background</p> <p>Stx bacteriophages are responsible for driving the dissemination of Stx toxin genes (<it>stx</it>) across their bacterial host range. Lysogens carrying Stx phages can cause severe, life-threatening disease and Stx toxin is an integral virulence factor. The Stx-bacteriophage vB_EcoP-24_B, commonly referred to as Ф24_B, is capable of multiply infecting a single bacterial host cell at a high frequency, with secondary infection increasing the rate at which subsequent bacteriophage infections can occur. This is biologically unusual, therefore determining the genomic content and context of Ф24_B compared to other lambdoid Stx phages is important to understanding the factors controlling this phenomenon and determining whether they occur in other Stx phages.</p> <p>Results</p> <p>The genome of the Stx2 encoding phage, Ф24_B was sequenced and annotated. The genomic organisation and general features are similar to other sequenced Stx bacteriophages induced from Enterohaemorrhagic <it>Escherichia coli</it> (EHEC), however Ф24_B possesses significant regions of heterogeneity, with implications for phage biology and behaviour<it>.</it> The Ф24_B genome was compared to other sequenced Stx phages and the archetypal lambdoid phage, lambda, using the Circos genome comparison tool and a PCR-based multi-loci comparison system.</p> <p>Conclusions</p> <p>The data support the hypothesis that Stx phages are mosaic, and recombination events between the host, phages and their remnants within the same infected bacterial cell will continue to drive the evolution of Stx phage variants and the subsequent dissemination of shigatoxigenic potential.</p>