title: In vivo influence of in vitro up-regulated genes in the virulence of an APEC strain associated with swollen head syndrome.
abstract: Avian Pathogenic Escherichia coli is responsible for significant economic losses in the poultry industry by causing a range of systemic or localized diseases collectively termed colibacillosis. The virulence mechanisms of these strains that are pathogenic in poultry and possibly pathogenic in humans have not yet been fully elucidated. This work was developed to study if over-expressed genes in a microarray assay could be potentially involved in the pathogenicity of an Avian Pathogenic Escherichia coli strain isolated from a swollen head syndrome case. For this study, five over-expressed genes were selected for the construction of null mutants [flgE (flagellar hook), tyrR (transcriptional regulator), potF (putrescine transporter), yehD (putative adhesin) and bfr (bacterioferritin)]. The constructed mutants were evaluated for their capacity for the adhesion and invasion of in vitro cultured cells, their motility capacity, and their pathogenic potential in one-day-old chickens compared with the wild-type strain (WT). The Δbfr strain showed a decreased adhesion capacity on avian fibroblasts compared with WT, in the presence and absence of alpha-D-mannopyranoside, and the ΔpotF strain showed decreased adhesion only in the absence of alpha-D-mannopyranoside. The ΔtyrR mutant had a reduced ability to invade Hep-2 cells. No mutant showed changes in invading CEC-32 cells. The mutants ΔflgE and ΔtyrR showed a decreased ability to survive in HD-11 cells. The motility of the mutant strains Δbfr, ΔyehD and ΔpotF was increased, while the ΔtyrR mutant showed reduction, and the ΔflgE became non-motile. No mutant strain caused the same mortality of the WT in one-day-old chickens, showing attenuation to different degrees.
authors.affiliation: a Department of Genetics, Evolution and Bioagents , Institute of Biology, University of Campinas , Campinas , SP , Brazil.
authors.forename: Jacqueline Boldrin
authors.initials: JB
authors.lastname: de Paiva
authors.affiliation: a Department of Genetics, Evolution and Bioagents , Institute of Biology, University of Campinas , Campinas , SP , Brazil.
authors.forename: Livia Pilatti Mendes
authors.initials: LP
authors.lastname: da Silva
authors.affiliation: b Adolfo Lutz Institute , São Paulo , SP , Brazil.
authors.forename: Monique Ribeiro Tiba
authors.initials: MR
authors.lastname: Casas
authors.affiliation: a Department of Genetics, Evolution and Bioagents , Institute of Biology, University of Campinas , Campinas , SP , Brazil.
authors.forename: Rogério Arcuri
authors.initials: RA
authors.lastname: Conceição
authors.affiliation: c Department of Microbiology , Londrina State University , Londrina , PR , Brazil.
authors.forename: Gerson
authors.initials: G
authors.lastname: Nakazato
authors.affiliation: d Department of Clinical Medicine, Faculty of Medical Sciences , University of Campinas , Campinas , SP , Brazil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: de Pace
authors.affiliation: e Department of Microbiology and Biochemistry, University of Texas Southwestern Medical Center , Dallas , TX , USA.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Sperandio
authors.affiliation: a Department of Genetics, Evolution and Bioagents , Institute of Biology, University of Campinas , Campinas , SP , Brazil.
authors.forename: Wanderley Dias
authors.initials: WD
authors.lastname: da Silveira
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D002460:Cell Line; D002642:Chick Embryo; D002645:Chickens / Q000382:microbiology*; D003573:Cytochrome b Group / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000235:genetics*; D005260:Female; D005293:Ferritins / Q000235:genetics; D020869:Gene Expression Profiling / Q000662:veterinary; D006801:Humans; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis / Q000662:veterinary; D011201:Poultry Diseases / Q000382:microbiology*; D015854:Up-Regulation; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D003573:Cytochrome b Group; D029968:Escherichia coli Proteins; D037521:Virulence Factors; D005293:Ferritins; C018032:bacterioferritin
keywords: APEC; bfr; flgE; potF; swollen head syndrome; tyrR; virulence; yehD