“ Bacteroides goldsteinii sp. nov.” Isolated from Clinical Specimens of Human Intestinal Origin

Abstract

ABSTRACT Phenotypic and phylogenetic studies were performed on an unknown gram-negative, strictly anaerobic, rod-shaped bacterium isolated from human clinical specimens. This organism was indole negative, resistant to 20% bile, produced acetic and a lesser amount of succinic acids as the major end products of glucose metabolism, and possessed a G+C content of approximately 43 mol%. Comparative 16S rRNA gene sequencing demonstrated that the unidentified bacterium was a member of the Cytophaga-Flavobacter-Bacteroides phylum of gram-negative bacteria and formed a close association (with an average sequence similarity of 93.6%) with the second subcluster of the Porphyromonas cluster in the Bacteroides subgroup. Phylogenetically and phenotypically it resembled Bacteroides merdae ; however, a 16S rRNA gene sequence divergence of approximately 5.5% between the unknown bacterium and B. merdae , as well as distinguishable biochemical characteristics, demonstrate that the unknown bacterium is genotypically and phenotypically distinct and represents a previously unknown subline within the Porphyromonas phylogenetic cluster. Furthermore, a DNA-DNA reassociation value of 17.8% between isolates WAL 12034 T (the type strain of this novel taxon) and ATCC 43184 T ( B. merdae type strain) also documented the separateness of the unknown species and B. merdae . Based on the phenotypic and phylogenetic findings, a new species, “ Bacteroides goldsteinii sp. nov,” is proposed. The G+C content of the DNA is 43 mol% for Bacteroides . The type strain of “ B. goldsteinii ” is WAL 12034 T (= CCUG 48944 T = ATCC BAA-1180 T ).