Riemerella columbina sp. nov., a bacterium associated with respiratory disease in pigeons

1 BCCM/LMG Culture Collection, Ledeganckstraat 35, University of Ghent, B-9000 Ghent, Belgium 2 Laboratory of Microbiology, Ledeganckstraat 35, University of Ghent, B-9000 Ghent, Belgium 3 Department of Medical Microbiology, University Hospital, Antwerp, Belgium 4 Clinic for Poultry, School of Veterinary Medicine Hannover, Hannover, Germany Author for correspondence: M. Vancanneyt. Tel: +32 9 2645115. Fax: +32 9 2645092. e-mail: Marc.Vancanneyt{at}rug.ac.be ABSTRACT Thirteen Gram-negative bacterial isolates were recovered from diseased pigeons and were tentatively classified as Riemerella anatipestifer -like strains based on conventional phenotypic features and disease symptoms. Phenotypic characteristics that differentiated the pigeon isolates from R. anatipestifer included their greyish-white to beige pigment formation on Columbia blood agar and the hydrolysis of aesculin. Furthermore, R. anatipestifer strains have thus far not been reported in pigeons. The phenotypic differences together with the unique host range of the new isolates have prompted the inclusion of these strains in a polyphasic taxonomic study. Extensive phenotypic examination, PAGE of total proteins and GC analysis of fatty acid contents revealed that the pigeon isolates constitute a homogeneous cluster, distinct from the R. anatipestifer reference strains. The phylogenetic position of representative strains was examined by using DNA-rRNA hybridizations and indicated that this taxon belongs to the genus Riemerella . Finally, DNA-binding values confirmed that the strains constitute a separate species for which the name Riemerella columbina sp. nov. is proposed. Strain LMG 11607 T was selected as the type strain. Clinical observations suggest that these organisms are involved in pathogenesis of respiratory diseases, similar to those associated with R. anatipestifer infections. However, the role of co-factors and the interaction with other agents are unknown. Key Words: Riemerella columbina sp. nov. • identification • polyphasic taxonomy