Microbacterium chengjingii sp. nov. and Microbacterium fandaimingii sp. nov., isolated from bat faeces of Hipposideros and Rousettus species.

Abstract

Four aerobic, Gram-stain-positive, rod-shaped bacteria (HY60T, HY54, HY82T and HY89) were isolated from bat faeces of Hipposideros and Rousettus species collected in PR China. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the four novel strains formed two separate but adjacent subclades close to Microbacterium agarici CGMCC 1.12260T (97.6-97.7 % similarity), Microbacterium humi JCM 18706T (97.3-97.5 %) and Microbacterium lindanitolerans JCM 30493T (97.3-97.4 %). The 16S rRNA gene sequence similarity was 98.3 % between strains HY60T and HY82T, and identical within strain pairs HY60T/HY54 and HY82T/HY89. The DNA G+C contents of strains HY60T and HY82T were 61.9 and 63.3 mol%, respectively. The digital DNA-DNA hybridization and average nucleotide identity values between each novel strain and their closest relatives were all below the 70 % and 95-96 % thresholds for species delimitation, respectively. All four novel strains contained anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0 and iso-C15 : 0 as the main fatty acids, MK-11 and MK-12 as the major respiratory quinones, and diphosphatidylglycerol, phosphatidylglycerol and one unidentified glycolipid as the predominant polar lipids. The cell-wall peptidoglycan was of B type and contained alanine, glutamate, glycine and ornithine. The acyl type of the muramic acid was glycolyl. The whole-cell sugars were rhamnose and ribose. Based on the foregoing polyphasic analyses, it was concluded that the four uncharacterized strains represented two novel species of the genus Microbacterium, for which the names Microbacterium chengjingii sp. nov. [type strain HY60T (=CGMCC 1.17468T=GDMCC 1.1951T=KACC 22102T)] and Microbacterium fandaimingii sp. nov. [type strain HY82T (=CGMCC 1.17469T=GDMCC 1.1949T=KACC 22101T)] are proposed, respectively.