Description of Pseudochrobactrum gen. nov., with the two species Pseudochrobactrum asaccharolyticum sp. nov. and Pseudochrobactrum saccharolyticum sp. nov.

Abstract

Two Gram-negative, rod-shaped, oxidase-positive, non-spore-forming, non-motile bacteria (CCUG 46016T and CCUG 33852T), isolated from a knee aspirate of a 66-year-old man and an industrial glue, respectively, were studied for their taxonomic position. On the basis of chemotaxonomic data [i.e. major ubiquinone (Q-10), major polar lipids (phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine) and major fatty acids (C18 : 1 ω7c and C19 : 0 cyclo ω8c)] and 16S rRNA gene sequence similarity, both strains belong to the Alphaproteobacteria. The presence of spermidine and putrescine as the predominant polyamines in CCUG 46016T were in agreement with its phylogenetic affiliation in the vicinity of the genus Ochrobactrum. 16S rRNA gene sequence similarities between both strains and established species within the genera Bartonella, Ochrobactrum and Brucella were less than 95 %. Although both organisms showed highest 16S rRNA gene sequence similarity to members of Brucella, phenotypic features (including chemotaxonomic features) were more like those of members of the genus Ochrobactrum. Sequence comparison of the recA genes confirmed the separate phylogenetic position of the two strains. On the basis of DNA–DNA pairing results and physiological and biochemical data, the two strains can be clearly differentiated from each other and from all known Ochrobactrum species. It is evident that these organisms represent two novel species in a new genus, Pseudochrobactrum gen. nov., for which the names Pseudochrobactrum asaccharolyticum sp. nov. (the type species, type strain CCUG 46016T=CIP 108977T) and Pseudochrobactrum saccharolyticum sp. nov. (type strain CCUG 33852T=CIP 108976T) are proposed.