Microbial Genomics
Microbiology Society
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Comparison of Shiga toxin-encoding bacteriophages in highly pathogenic strains of Shiga toxin-producing Escherichia coli O157:H7 in the UK
Volume: 6, Issue: 3
DOI 10.1099/mgen.0.000334
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Abstract

Over the last 35 years in the UK, the burden of Shiga toxin-producing (STEC) O157:H7 infection has, during different periods of time, been associated with five different sub-lineages (1983–1995, Ia, I/IIa and I/IIb; 1996–2014, Ic; and 2015–2018, IIb). The acquisition of a stx2a-encoding bacteriophage by these five sub-lineages appears to have coincided with their respective emergences. The Oxford Nanopore Technologies (ONT) system was used to sequence, characterize and compare the stx-encoding prophages harboured by each sub-lineage to investigate the integration of this key virulence factor. The stx2a-encoding prophages from each of the lineages causing clinical disease in the UK were all different, including the two UK sub-lineages (Ia and I/IIa) circulating concurrently and causing severe disease in the early 1980s. Comparisons between the stx2a-encoding prophage in sub-lineages I/IIb and IIb revealed similarity to the prophage commonly found to encode stx2c, and the same site of bacteriophage integration (sbcB) as stx2c-encoding prophage. These data suggest independent acquisition of previously unobserved stx2a-encoding phage is more likely to have contributed to the emergence of STEC O157:H7 sub-lineages in the UK than intra-UK lineage to lineage phage transmission. In contrast, the stx2c-encoding prophage showed a high level of similarity across lineages and time, consistent with the model of stx2c being present in the common ancestor to extant STEC O157:H7 and maintained by vertical inheritance in the majority of the population. Studying the nature of the stx-encoding bacteriophage contributes to our understanding of the emergence of highly pathogenic strains of STEC O157:H7.

Keywords
https://www.researchpad.co/tools/openurl?pubtype=article&doi=10.1099/mgen.0.000334&title=Comparison of Shiga toxin-encoding bacteriophages in highly pathogenic strains of Shiga toxin-producing <i>Escherichia coli</i> O157:H7 in the UK&author=Daniel A. Yara,David R. Greig,David L. Gally,Timothy J. Dallman,Claire Jenkins,&keyword=Escherichia coli O157:H7,bacteriophage,Shiga toxin,whole-genome sequencing,&subject=Research Article,Microbial evolution and epidemiology: Communicable disease genomics,