title: Discovery and Characterization of Human-Urine Utilization by Asymptomatic-Bacteriuria-Causing Streptococcus agalactiae.
abstract: Streptococcus agalactiae causes both symptomatic cystitis and asymptomatic bacteriuria (ABU); however, growth characteristics of S. agalactiae in human urine have not previously been reported. Here, we describe a phenotype of robust growth in human urine observed in ABU-causing S. agalactiae (ABSA) that was not seen among uropathogenic S. agalactiae (UPSA) strains isolated from patients with acute cystitis. In direct competition assays using pooled human urine inoculated with equal numbers of a prototype ABSA strain, designated ABSA 1014, and any one of several UPSA strains, measurement of the percentage of each strain recovered over time showed a markedly superior fitness of ABSA 1014 for urine growth. Comparative phenotype profiling of ABSA 1014 and UPSA strain 807, isolated from a patient with acute cystitis, using metabolic arrays of >2,500 substrates and conditions revealed unique and specific l-malic acid catabolism in ABSA 1014 that was absent in UPSA 807. Whole-genome sequencing also revealed divergence in malic enzyme-encoding genes between the strains predicted to impact the activity of the malate metabolic pathway. Comparative growth assays in urine comparing wild-type ABSA and gene-deficient mutants that were functionally inactivated for the malic enzyme metabolic pathway by targeted disruption of the maeE or maeK gene in ABSA demonstrated attenuated growth of the mutants in normal human urine as well as synthetic human urine containing malic acid. We conclude that some S. agalactiae strains can grow in human urine, and this relates in part to malic acid metabolism, which may affect the persistence or progression of S. agalactiae ABU.
authors.affiliation: School of Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, QLD, Australia.
authors.forename: Deepak S
authors.initials: DS
authors.lastname: Ipe
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.
authors.forename: Nouri L
authors.initials: NL
authors.lastname: Ben Zakour
authors.affiliation: School of Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, QLD, Australia.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Sullivan
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Beatson
authors.affiliation: Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: Kimberly B
authors.initials: KB
authors.lastname: Ulett
authors.affiliation: Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: William H
authors.initials: WH
authors.lastname: Benjamin
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Davies
authors.affiliation: Institute for Glycomics, Griffith University, Gold Coast Campus, QLD, Australia.
authors.forename: Samantha J
authors.initials: SJ
authors.lastname: Dando
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.
authors.forename: Nathan P
authors.initials: NP
authors.lastname: King
authors.affiliation: School of Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, QLD, Australia.
authors.forename: Allan W
authors.initials: AW
authors.lastname: Cripps
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.
authors.forename: Mark A
authors.identifier: http://orcid.org/0000-0003-4863-9260
authors.initials: MA
authors.lastname: Schembri
authors.affiliation: Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom.
authors.forename: Gordon
authors.initials: G
authors.lastname: Dougan
authors.affiliation: School of Medical Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, QLD, Australia Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA g.ulett@griffith.edu.au.
authors.forename: Glen C
authors.identifier: http://orcid.org/0000-0002-9638-8091
authors.initials: GC
authors.lastname: Ulett
mesh_terms: D000328:Adult; D000818:Animals; D058345:Asymptomatic Infections; D001437:Bacteriuria / Q000382:microbiology*; D003556:Cystitis / Q000382:microbiology*; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008293:Malates / Q000378:metabolism* / Q000652:urine*; D008297:Male; D053858:Metabolic Networks and Pathways / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D012189:Retrospective Studies; D013292:Streptococcus agalactiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014552:Urinary Tract Infections / Q000382:microbiology
chemical_list: D008293:Malates; C030298:malic acid