Characterisation of three bacteriophages infecting serovars of Salmonella enterica

• Main Author: Turner, D.
• Published: University of the West of England, Bristol 2013
• Subjects: 571.99344
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.589109

A collection of three newly isolated Salmonella bacteriophages, vB_SenS-Ent1, vB_SenS-Ent2 and vB_SenS-Ent3 was established. These bacteriophages were characterised by electron microscopy, host range, sensitivity to restriction enzymes and profiles of structural proteins on SDS-PAGE gels. The complete genome sequences of each bacteriophage were established to greater than 30x coverage and bioinformatics analysis identified the functions of a number of coding sequences. Since the last update of virus taxonomy by the ICTV a number of additional genome sequences for bacteriophages infecting the genus Salmonella have been reported in the literature. To date, all but one of the Siphoviridae comprising the Salmonella bacteriophages with fully sequenced genomes remain unclassified by the ICTV. Comparative genomic analysis reveals that a number of these phages form a coherent group within the Siphoviridae and supports the establishment of a new genus, the “Setp3likeviruses”. The proposed genus includes 5 bacteriophages infecting Salmonella; SETP3, vB_SenS-Ent1, SE2, wksl3 and SS3e, and 5 infecting Escherichia; K1G, K1H, K1ind1, K1ind2 and K1ind3. This group share identical virion morphology, have terminally redundant, circularly permuted genomes ranging between 42-45 kb in size and are characterised by high nucleotide sequence similarity, shared homologous proteins and conservation of gene order. Bioluminescent bacterial reporters, transformed to express the luxCDABE operon of Photorhabdus luminescens, were used to establish the activity of the vB_SenS-Ent bacteriophages in microtitre broth lysis assays, efficacy as biological control agents for the removal of Salmonella in contaminated foods and for spatial measurements of plaque expansion in agar overlays.