Morphological and genomic characteristics of two novel actinomycetes, Ornithinimicrobium sufpigmenti sp. nov. and Ornithinimicrobium faecis sp. nov. isolated from bat faeces (Rousettus leschenaultia and Taphozous perforates)

Four Gram-staining-positive, aerobic, non-motile, circle-shaped bacteria were isolated from the faeces of bats (Rousettus leschenaultia and Taphozous perforates) collected from Guangxi autonomous region (E106 degrees 49 ' 20 '', N22 degrees 20 ' 54 '') and Yunnan province (E102 degrees 04 ' 39 '', N25 degrees 09 ' 10 '') of South China. Strains HY006(T) and HY008 shared highly 16S rRNA gene sequence similarity to those of Ornithinimicrobium pratense W204(T) (99.3%) and O. flavum CPCC 203535(T) (97.3%), while the strains HY1745 and HY1793(T) were closest to the type strains O. ciconiae H23M54(T) (98.7%), O. cavernae CFH 30183(T) (98.3%), and O. murale 01-Gi-040(T) (98.1%). Furthermore, when compared to the other members of the genus Ornithinimicrobium, the digital DNA-DNA hybridization and average nucleotide identity values of the four novel strains were within the ranges of 19.6-33.7% and 70.6-87.4%, respectively, both of which were below the respective recommended cutoff values of 70.0% and 95-96%. Significantly, strain HY006(T) was resistant to chloramphenicol and linezolid whereas strain HY1793(T) was resistant to erythromycin, clindamycin (intermediately), and levofloxacin (intermediately). The main cellular fatty acids (>20.0%) of our isolates were iso-C-15:0 and iso-C-16:0. Strains HY006(T) and HY1793(T) contained ornithine as the diagnostic diamino acid, also along with the alanine, glycine and glutamic acid in their cell wall. Based on phylogenetic, chemotaxonomic and phenotypic analyses, these four strains could be classified as two novel species of the genus Ornithinimicrobium, for which the names Ornithinimicrobium sufpigmenti sp. nov. and Ornithinimicrobium faecis sp. nov. are proposed. The type strains are HY006(T) (=CGMCC 1.16565(T) =JCM 33397(T)) and HY1793(T) (=CGMCC 1.19143(T) =JCM 34881(T)), respectively.

Automated summary

Four novel strains of Gram-staining-positive, aerobic, non-motile, circle-shaped bacteria were isolated from bat feces in South China. These strains belong to the genus Ornithinimicrobium and were named Ornithinimicrobium sufpigmenti and Ornithinimicrobium faecis. This discovery is significant for understanding the characteristics and diversity of these bacteria.