Enterorhabdus caecimuris sp. nov., a member of the family Coriobacteriaceae isolated from a mouse model of spontaneous colitis, and emended description of the genus Enterorhabdus Clavel et al. 2009

Abstract

The C3H/HeJBir mouse model of intestinal inflammation was used for isolation of a Gram-positive, rod-shaped, non-spore-forming bacterium (B7(T)) from caecal suspensions. On the basis of partial 16S rRNA gene sequence analysis, strain B7(T) was a member of the class Actinobacteria, family Coriobacteriaceae, and was related closely to Enterorhabdus mucosicola Mt1B8(T) (97.6 %). The major fatty acid of strain B7(T) was C(16 : 0) (19.1 %) and the respiratory quinones were mono- and dimethylated. Cells were aerotolerant, but grew only under anoxic conditions. Strain B7(T) did not convert the isoflavone daidzein and was resistant to cefotaxime. The results of DNA-DNA hybridization experiments and additional physiological and biochemical tests allowed the genotypic and phenotypic differentiation of strain B7(T) from the type strain of E. mucosicola. Therefore, strain B7(T) represents a novel species, for which the name Enterorhabdus caecimuris sp. nov. is proposed. The type strain is B7(T) (=DSM 21839(T) =CCUG 56815(T)).

Fig. 1.

Phylogenetic position of strain B7^T within the family Coriobacteriaceae, based on a neighbour-joining analysis of 16S rRNA gene sequences (1338 bp). Bootstrap values based on 1000 resamplings are shown at branch nodes. Hash signs indicate that the corresponding nodes were also recovered in the tree generated using the maximum-parsimony method. Eubacterium limosum ATCC 8486^T, a member of the phylum Firmicutes, was used as an outgroup. Bar, 10 substitutions per 100 nucleotide positions.

Fig. 2.

Cluster analysis of FT-IRS spectra of strain B7^T and closely related strains. Data were taken from this study and Clavel et al. (2009). Dates indicate date of measurement. Asterisks indicate results from this study.