Lysinibacillus contaminans sp. nov., isolated from surface water

Abstract

A Gram-positive-staining, aerobic, endospore-forming bacterium, isolated as a contamination from an enrichment of enteric bacteria from surface water, was studied using a polyphasic taxonomic approach. 16S rRNA gene sequence similarity comparisons revealed that strain FSt3A(T) was grouped in the genus Lysinibacillus, most closely related to Lysinibacillus xylanilyticus XDB9(T) (98.1%), Lysinibacillus parviboronicapiens BAM-582(T) and Lysinibacillus sphaericus DSM 28(T) (both 98.0%). The 16S rRNA gene sequence similarity to other species of the genus Lysinibacillus was <97.5%. The allocation to the genus Lysinibacillus was supported by a detailed chemotaxonomic characterization revealing a cell wall containing alanine, glutamic acid, aspartic acid and the diagnostic diamino acid lysine in a molar ratio of 1.6:1:0.9:0.8 (peptidoglycan type A4α), the major menaquinones MK-7 and MK-6, and polar lipids consisting of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, four unknown phospholipids, one unknown aminophospholipid and one unidentified aminolipid. The major fatty acids were iso- and anteiso-branched fatty acids. DNA-DNA hybridizations with the type strains of the most closely related species, L. parviboronicapiens DSM 25242(T), L. xylanilyticus DSM 23493(T) and L. sphaericus DSM 28(T), in addition to the results of physiological and biochemical tests, allowed genotypic and phenotypic differentiation of strain FSt3A(T) from these related species. Thus, FSt3A(T) represents a novel species of the genus Lysinibacillus, for which the name Lysinibacillus contaminans sp. nov. is proposed, with FSt3A(T) ( =CCM 8383(T) =DSM 25560(T) =CIP 110362(T)) as the type strain.