Description of Riemerella columbipharyngis sp. nov., isolated from the pharynx of healthy domestic pigeons (Columba livia f. domestica), and emended description of the genus Riemerella, Riemerella anatipestifer and Riemerella columbina

A group of 11 bacterial strains was isolated during microbiological investigations of pharyngeal swabs collected from domestic pigeons (Columba livia f. domestica). Phenotypic properties of the isolates closely resembled those of members of the genus Riemerella within the family Flavobacteriaceae. The genus presently contains two species, Riemerella anatipestifer and Riemerella columbina. The pigeon isolates differed from R. columbina by their lack of pigment production and negative CAMP co-haemolysis reaction. They grew more slowly at 37 °C under microaerobic conditions and showed reduced viability during storage under aerobic conditions at different temperatures, compared with both Riemerella species. Comparisons of protein profiles with matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS analysis allowed differentiation between the new pigeon isolates and both R. anatipestifer and R. columbina. Phylogenetic analysis based on 16S rRNA gene and rpoB gene (encoding RNA polymerase beta subunit) sequences supported the affiliation of the 11 strains to a novel species within the genus Riemerella, for which we propose the name Riemerella columbipharyngis sp. nov. The type strain is 8151(T) (=DSM 24015(T) = LMG 26094(T)). Emended descriptions of the genus Riemerella and of its species Riemerella anatipestifer and Riemerella columbina are also presented.