title: Fhua and HgbA, outer membrane proteins of Actinobacillus pleuropneumoniae: their role as virulence determinants.
abstract: For the recently described serotype 15 of biotype I and serotypes 13 and 14 of biotype II of Actinobacillus pleuropneumoniae, fhuA and hgbA were detected by polymerase chain reaction and DNA sequencing. To determine the substrate specificity of the iron receptors FhuA and HgbA and to study their role in the virulence of A. pleuropneumoniae, we used two isogenic A. pleuropneumoniae serotype 1 deletion mutants of fhuA and hgbA. Different sources of iron and siderophores were tested in growth promotion assays. FhuA and HgbA are specific for their ligands ferrichrome and hemoglobin, respectively. The virulence of the two deletion mutant strains was evaluated in experimental infections using specific pathogen-free piglets. While the fhuA mutant (DG02) was as highly virulent as the parental strain S4074, the virulence of the hgbA mutant (DeltahgbA) was reduced. Our data indicate that both FhuA and HgbA are conserved among all serotypes and biotypes of A. pleuropneumoniae and that HgbA, the receptor for porcine hemoglobin, may play a role in virulence.
authors.affiliation: Canadian Resrarch Network on Bacterial Pathogens of Swine, Université de Montréal, Canada.
authors.forename: Lara
authors.initials: L
authors.lastname: Shakarji
authors.forename: Leonie G
authors.initials: LG
authors.lastname: Mikael
authors.forename: Ramakrishnan
authors.initials: R
authors.lastname: Srikumar
authors.forename: Marylène
authors.initials: M
authors.lastname: Kobisch
authors.forename: James W
authors.initials: JW
authors.lastname: Coulton
authors.forename: Mario
authors.initials: M
authors.lastname: Jacques
mesh_terms: D016977:Actinobacillus pleuropneumoniae / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D005291:Ferrichrome / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006454:Hemoglobins / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D009154:Mutation; D010802:Phylogeny; D012703:Serotyping; D017262:Siderophores / Q000378:metabolism; D013379:Substrate Specificity; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D006454:Hemoglobins; D017262:Siderophores; D037521:Virulence Factors; C017206:hemoglobin-binding protein, bacteria; D005291:Ferrichrome; D007501:Iron