Paenochrobactrum gallinarii gen. nov., sp. nov., isolated from air of a duck barn, and reclassification of Pseudochrobactrum glaciei as Paenochrobactrum glaciei comb. nov.

Abstract

A Gram-negative, rod-shaped, oxidase-positive, non-spore-forming, non-motile bacterium (Sa25T) was isolated from air of a duck barn. 16S rRNA gene and recA sequence analyses clearly placed the isolate in the vicinity of the Brucella–Ochrobactrum–Pseudochrobactrum group, with the closest relative being Pseudochrobactrum glaciei KMM 3858T. This allocation was confirmed by analyses of the quinone system (ubiquinone Q-10), fatty acid data (major fatty acids C18 : 1 ω7c and C19 : 0 cyclo ω8c) and polar lipid profile (major components diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and unknown aminolipid AL1; moderate amounts of three unknown polar lipids, L1–L3, an unknown aminolipid and an unknown aminophospholipid APL2). The polyamine pattern of Sa25T exhibited the major compound putrescine and moderate amounts of spermidine; a similar polyamine pattern with the major compound putrescine was also detected in Pseudochrobactrum glaciei KMM 3858T. DNA–DNA hybridization of strain Sa25T with Pseudochrobactrum glaciei KMM 3858T and the type strains of the other Pseudochrobactrum species showed values ranging from 50.3 to 24.8 %, and physiological and biochemical data clearly differentiated this isolate from the described Pseudochrobactrum species. Since Sa25T and Pseudochrobactrum glaciei KMM 3858T form a distinct lineage in the 16S rRNA gene sequence-based phylogenetic tree, and this separate position is supported by unique characteristics of their polyamine patterns and polar lipid profiles, we propose the novel genus Paenochrobactrum gen. nov., with the type species Paenochrobactrum gallinarii sp. nov. (type strain Sa25T =CCUG 57736T =CCM 7656T) and the reclassification of Pseudochrobactrum glaciei as Paenochrobactrum glaciei comb. nov. (type strain Pi26T =KMM 3858T =NRIC 0733T =JCM 15115T).