title: Stx1 prophage excision in Escherichia coli strain PA20 confers strong curli and biofilm formation by restoring native mlrA.
abstract: Prophage insertions in Escherichia coli O157:H7 mlrA contribute to the low expression of curli fimbriae and biofilm observed in many clinical isolates. Varying levels of CsgD-dependent curli/biofilm expression are restored to strains bearing prophage insertions in mlrA by mutation of regulatory genes affecting csgD Our previous study identified strong biofilm- and curli-producing variants in O157:H7 cultures that had lost the mlrA-imbedded prophage characteristic of the parent population, suggesting prophage excision as a mechanism for restoring biofilm properties. In this study, we compared genomic, transcriptomic and phenotypic properties of parent strain PA20 (stx1, stx2) and its prophage-cured variant, 20R2R (stx2), and confirmed the mechanism underlying the differences in biofilm formation.
authors.affiliation: Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, Wyndmoor, PA 19038-8542, USA gaylen.uhlich@ars.usda.gov.
authors.forename: Gaylen A
authors.initials: GA
authors.lastname: Uhlich
authors.affiliation: Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, Wyndmoor, PA 19038-8542, USA.
authors.forename: Chin-Yi
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, Wyndmoor, PA 19038-8542, USA.
authors.forename: Bryan J
authors.initials: BJ
authors.lastname: Cottrell
authors.affiliation: Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, Wyndmoor, PA 19038-8542, USA.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Hofmann
authors.affiliation: Environmental Microbial and Food Safety Laboratory, Agricultural Research Service, US Department of Agriculture, Beltsville, MD 20705, USA.
authors.forename: Xianghe
authors.initials: X
authors.lastname: Yan
authors.affiliation: Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, Wyndmoor, PA 19038-8542, USA.
authors.forename: Ly
authors.initials: L
authors.lastname: Nguyen
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D018441:Biofilms / Q000254:growth & development*; D003090:Coliphages / Q000235:genetics; D003224:Congo Red / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D019453:Escherichia coli O157 / Q000235:genetics* / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D010861:Fimbriae, Bacterial / Q000378:metabolism; D020869:Gene Expression Profiling; D005809:Genes, Regulator; D023281:Genomics; D009154:Mutation; D010641:Phenotype; D039002:Prophages / Q000235:genetics*; D022622:Shiga Toxin 1 / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014775:Virus Activation
chemical_list: D001426:Bacterial Proteins; C499694:CsgD protein, E coli; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C451279:MlrA protein, E coli; D022622:Shiga Toxin 1; D015534:Trans-Activators; C077481:Crl protein, Bacteria; D003224:Congo Red
keywords: Congo red; MlrA; STEC; biofilm; curli; serotype O157:H7