title: Insertion site occupancy by stx2 bacteriophages depends on the locus availability of the host strain chromosome.
abstract: Shiga toxin-producing Escherichia coli (STEC) is an emergent pathogen characterized by the expression of Shiga toxins, which are encoded in the genomes of lambdoid phages. These phages are infectious for other members of the Enterobacteriaceae and establish lysogeny when they integrate into the host chromosome. Five insertion sites, used mainly by these prophages, have been described to date. In the present study, the insertion of stx(2) prophages in these sites was analyzed in 168 STEC strains isolated from cattle. Additionally, insertion sites were determined for stx(2) phages which (i) converted diverse laboratory host strains, (ii) coexisted with another stx(2) prophage, and (iii) infected a recombinant host strain lacking the most commonly used insertion site. Results show that depending on the host strain, phages preferentially use one insertion site. For the most part, yehV is occupied in STEC strains while wrbA is preferentially selected by the same stx phages in E. coli laboratory strains. If this primary insertion site is unavailable, then a secondary insertion site is selected. It can be concluded that insertion site occupancy by stx phages depends on the host strain and on the availability of the preferred locus in the host strain.
authors.affiliation: University of Barcelona, Diagonal 645, 08028 Barcelona, Spain. mmuniesa@ub.edu
authors.forename: Ruth
authors.initials: R
authors.lastname: Serra-Moreno
authors.forename: Juan
authors.initials: J
authors.lastname: Jofre
authors.forename: Maite
authors.initials: M
authors.lastname: Muniesa
mesh_terms: D000818:Animals; D001287:Attachment Sites, Microbiological / Q000235:genetics*; D010582:Bacteriophage lambda / Q000235:genetics / Q000502:physiology*; D002417:Cattle / Q000382:microbiology; D002876:Chromosomes, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000821:virology*; D019453:Escherichia coli O157 / Q000235:genetics / Q000821:virology; D019426:Integrases / Q000235:genetics; D008242:Lysogeny; D009154:Mutation; D039002:Prophages; D012756:Sheep / Q000382:microbiology; D022641:Shiga Toxin 2 / Q000235:genetics*; D013045:Species Specificity; D016662:Virus Integration
chemical_list: D022641:Shiga Toxin 2; D019426:Integrases