Submitted to: Conference Research Workers Disease Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 10/10/2007
Publication Date: 12/2/2007
Citation: Tabatabai, L.B., Zehr, E.S., Zimmerli, M.K., Nagaraja, K.V. 2007. Acquisition of iron by Ornithbacterium rhinotracheale [abstract]. Conference Research Workers Disease Meeting, December 1-4, 2007. p.121.
Technical Abstract: Ornithobacterium rhinotracheale (ORT) is an emerging respiratory pathogen of poultry in North America causing economic losses to the poultry industry, and is associated with airsacculitis, pleuritis, consolidation of lungs and pneumonia of poultry. Little is known about the molecular mechanisms of infection that may play a role in the pathogenesis of this organism. In this study we explore the mechanism of iron acquisition by O. rhinotracheale. O. rhinotracheale grown under iron deprivation in brain heart infusion broth containing 200 µM 2,2’-dipyridyl did not secrete siderophores into the growth medium nor on chromazurol (CAS)-agar. Iron sources that supported growth included Fe(III) and Fe(II), bovine, sheep and porcine hemoglobins and ovotransferrin. Bovine transferrin, bovine apo-transferrin, bovine lactoferrin, and hemin did not support growth of O. rhinotracheale. Proteins involved in iron acquisition were identified from a 2-D gel of an outer membrane preparation and included H. haemophilus homologs heme-hemopexin, hxuB (Accession No. P45356), and an iron transport protein (Accession No. Q57449). Furthermore, seventy two field strains of ORT obtained from various turkey flocks were tested for their sensitivity to the iron chelator, 2,2’-dipyridyl, in a microtiter plate assay. Results showed that 22 of 72 strains tested were resistant to the iron chelator at concentrations of 50 and 100 µM, suggesting the presence of an inducible iron acquisition mechanism. This is the first report on the identification of the iron acquisition mechanism of O. rhinotracheale. The information obtained in this study allows us to design strategies for the control of O. rhinotracheale infection of poultry.