Classification of three corynebacterial strains isolated from the Northern Bald Ibis (Geronticus eremita): proposal of Corynebacterium choanae sp. nov., Corynebacterium pseudopelargi sp. nov., and Corynebacterium gerontici sp. nov.

Three Gram-stain-positive, rod-to-coccoid-shaped, catalase-positive and non-motile bacterial strains isolated from the choanae of a Northern bald ibis, designated strains 200CH T , W8 T and 812CH T , respectively, were subjected to comprehensive taxonomic characterization. The three strains were oxidase-negative. The 16S rRNA gene sequence of 200CH T showed highest similarities to Corynebacterium epidermidicanis 410 T (96.7 %) followed by Corynebacterium argentoratense DSM 44202 T , Corynebacterium ulcerans NCTC 7910 T and Corynebacterium pseudotuberculosis CIP 102968 T (each 96.3 %). Strains W8 T and 812CH T both showed highest 16S rRNA gene sequence similarities to Corynebacterium pelargi 136/3 T (98.0 and 99.9 %, respectively). Comparison of the partial housekeeping gene sequence of fusA showed higher sequence similarities of 812CH T to C. pelargi (95.8 %) than W8 T (90.9 %) which was also confirmed by corresponding amino acid sequences. In both, fusA gene and corresponding protein sequence strain 200CH T showed low sequence similarities to C. epidermidicanis 410 T (81.6 and 87.4 %, respectively). Strains 812CH T and W8 T had 76.7 % ANI similarity to each other and 88.2 and 76.4 % to C. pelargi 136/3 T , respectively. In silico DNA-DNA hybridization values for 812CH T and W8 T were 22.1 % among the two strains and 35.3 and 21.7 % to C. pelargi 136/3 T , respectively. These data not only demonstrate that strain W8 T is a representative of a novel species, but despite the high 16S rRNA gene sequence similarity to C. pelargi , strain 812CH T is also a representative of another novel species. All three strains possessed corynemycolic acids and contained meso -diaminopimelic acid as the diagnostic diamino acid of the peptidoglycan. The two strains, 200CH T and W8 T , are distinguished from each other and established Corynebacterium species phylogenetically and phenotypically. In conclusion, three novel species of the genus Corynebacterium are proposed, namely Corynebacteriumpseudopelargi 812CH T (=LMG 30627 T =CCM 8832 T ) , Corynebacterium choanae 200CH T (=LMG 30628 T =CCM 8831 T ) and Corynebacteriumgerontici W8 T (=LMG 30629 T =CCM 8833 T ), respectively.