title: Monitoring F1651 P-like fimbria expression at the single-cell level reveals a highly heterogeneous phenotype.
abstract: F1651 and the pyelonephritis-associated pili (Pap) are two members of the type P family of adhesive factors. They play a key role in establishing disease caused by extraintestinal pathogenic Escherichia coli (ExPEC) strains in animals and humans. Both F1651 and Pap are under the control of an epigenetic and reversible switch that defines the number of fimbriated (ON) and afimbriated (OFF) cells within a clonal population. Using the Gfp reporter system, we monitored in vitro the level of fluorescence intensity corresponding to the F1651 and Pap fimbrial synthesis. Monitoring individual Escherichia coli cells by flow cytometry and by real-time fluorescence microscopy, we identified cells associated with a low or high level of fluorescence intensity and a large amount of cells with partial levels of fluorescence, mostly present in the F1651 system. This mixed population identified through fluorescence intensity could be attributed to the high switching rate previously observed in F1651-positive bacteria. The fimbrial heterogeneous phenotype for these ExPEC could represent increased fitness in unpredictable environments. Our study illustrates that within the large repertoire of fimbrial variants such as the well-characterized Pap, F1651 is an exquisite example of regulatory expression that arms the bacterium with strategies for surviving in more than one particular environment.
authors.affiliation: Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP) and Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Graveline
authors.affiliation: Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP) and Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Canada.
authors.forename: Rémi
authors.initials: R
authors.lastname: Lavoie
authors.affiliation: Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP) and Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Garneau
authors.affiliation: Département de Microbiologie et Immunologie, Faculté de Médecine, Université de Montréal, Montréal, Canada.
authors.forename: France
authors.initials: F
authors.lastname: Daigle
authors.affiliation: Département de Microbiologie et Immunologie, Faculté de Médecine, Université de Montréal, Montréal, Canada.
authors.forename: Serge
authors.initials: S
authors.lastname: Sénéchal
authors.affiliation: Institut National de la Recherche Agronomique, Saint-Genès-Champanelle, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Martin
authors.affiliation: Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP) and Centre de Recherche en Infectiologie Porcine (CRIP), Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Canada josee.harel@umontreal.ca.
authors.forename: Josée
authors.initials: J
authors.lastname: Harel
mesh_terms: D019677:Artificial Gene Fusion; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000096:biosynthesis*; D010861:Fimbriae, Bacterial / Q000378:metabolism*; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D008856:Microscopy, Fluorescence; D010641:Phenotype
chemical_list: D049452:Green Fluorescent Proteins; D036781:Fimbriae Proteins