title: Characterization of the Prophage Repertoire of AfricanSalmonellaTyphimurium ST313 Reveals High Levels of Spontaneous Induction of Novel Phage BTP1.
abstract: In the past 30 years,Salmonellabloodstream infections have become a significant health problem in sub-Saharan Africa and are responsible for the deaths of an estimated 390,000 people each year. The disease is predominantly caused by a recently described sequence type ofSalmonellaTyphimurium: ST313, which has a distinctive set of prophage sequences. We have thoroughly characterized the ST313-associated prophages both genetically and experimentally. ST313 representative strain D23580 contains five full-length prophages: BTP1, Gifsy-2D23580, ST64BD23580, Gifsy-1D23580, and BTP5. We show that commonS.Typhimurium prophages Gifsy-2, Gifsy-1, and ST64B are inactivated in ST313 by mutations. Prophage BTP1 was found to be a functional novel phage, and the first isolate of the proposed new species "Salmonella virus BTP1", belonging to theP22virusgenus. Surprisingly, ∼109BTP1 virus particlesperml were detected in the supernatant of non-induced, stationary-phase cultures of strain D23580, representing the highest spontaneously induced phage titer so far reported for a bacterial prophage. High spontaneous induction is shown to be an intrinsic property of prophage BTP1, and indicates the phage-mediated lysis of around 0.2% of the lysogenic population. The fact that BTP1 is highly conserved in ST313 poses interesting questions about the potential fitness costs and benefits of novel prophages in epidemicS.Typhimurium ST313.
authors.affiliation: Institute of Integrative Biology, University of Liverpool Liverpool, UK.
authors.forename: Siân V
authors.initials: SV
authors.lastname: Owen
authors.affiliation: Institute of Integrative Biology, University of Liverpool Liverpool, UK.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Wenner
authors.affiliation: Institute of Integrative Biology, University of Liverpool Liverpool, UK.
authors.forename: Rocío
authors.initials: R
authors.lastname: Canals
authors.affiliation: Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, KU Leuven Leuven, Belgium.
authors.forename: Angela
authors.initials: A
authors.lastname: Makumi
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University Uppsala, Sweden.
authors.forename: Disa L
authors.initials: DL
authors.lastname: Hammarlöf
authors.affiliation: Institute of Infection and Global Health, University of LiverpoolLiverpool, UK; Malawi-Liverpool-Wellcome Trust Clinical Research ProgrammeBlantyre, Malawi.
authors.forename: Melita A
authors.initials: MA
authors.lastname: Gordon
authors.affiliation: Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, KU Leuven Leuven, Belgium.
authors.forename: Abram
authors.initials: A
authors.lastname: Aertsen
authors.affiliation: Liverpool School of Tropical Medicine Liverpool, UK.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Feasey
authors.affiliation: Institute of Integrative Biology, University of Liverpool Liverpool, UK.
authors.forename: Jay C D
authors.initials: JC
authors.lastname: Hinton
keywords: BTP5; D23580; Gifsy; P22; ST64B; polylysogeny