Isolation of bacteria from the ileal mucosa of TNFdeltaARE mice and description of Enterorhabdus mucosicola gen. nov., sp. nov.

Abstract

The diversity of bacteria associated with inflamed mucosa was investigated by culturing ileal samples from TNF(deltaARE) mice on a selective medium containing mucin. Among eight isolates, two strains (Mt1B3 and Mt1B8(T)) belonged to bacterial groups not yet cultured from the mouse intestine. Whereas strain Mt1B3 was identified as a member of the family Planococcaceae and is closely related to Sporosarcina species and Filibacter limicola DSM 13886(T), strain Mt1B8(T) was a novel bacterium. Based on phylogenetic analysis, strain Mt1B8(T) is a member of the family Coriobacteriaceae. The closest relatives with validly published names were Asaccharobacter celatus, Adlercreutzia equolifaciens (<96 % similarity) and Eggerthella species (<92 %). With respect to Asaccharobacter celatus and Eggerthella, the phylogenetic position of strain Mt1B8(T) was confirmed at the chemotaxonomic level by Fourier-transform infrared spectroscopic analysis. The major fatty acid of strain Mt1B8(T) is C(16 : 0) (23.9 %). Menaquinones were monomethylated. DNA-DNA relatedness between strain Mt1B8(T) and Asaccharobacter celatus DSM 18785(T) was 28 %. Strain Mt1B8(T) is a Gram-positive-staining rod that does not form spores and has a high DNA G+C content (64.2 mol%). Cells are aerotolerant but grow only under strictly anoxic conditions. They are sensitive to cefotaxime, clarithromycin, erythromycin, metronidazole, tetracycline, tobramycin and vancomycin. API and VITEK analysis showed the ability of strain Mt1B8(T) to convert a variety of amino acid derivatives. According to these findings, it is proposed to create a novel genus and species, Enterorhabdus mucosicola gen. nov., sp. nov., to accommodate strain Mt1B8(T). The type strain of Enterorhabdus mucosicola is Mt1B8(T) (=DSM 19490(T) =CCUG 54980(T)).