Proposal for Reclassification of Bacteroides asaccharolyticus, Bacteroides gingivalis, and Bacteroides endodontalis in a New Genus, Porphyromonas

Abstract

The asaccharolytic, pigmented Bacteroides, Bacteroides asaccharolyticus, Bacteroides gingivalis, and Bacteroides endodontalis, form a group of relatively homogeneous species which differ markedly in biochemical and chemical properties from the type species of Bacteroides, Bacteroides fragilis (Castellani and Chalmers), such that they should not be retained within this genus. Therefore, we propose that Bacteroides asaccharolyticus (Holdeman and Moore) Finegold and Barnes, Bacteroides gingivalis Coykendhll, Kaczmarek and Slots, and Bacteroides endodontalis van Steenbergen, van Winkelhoff, Mayrand, Grenier and de Graaff be reclassified in a new genus, Porphyromonas, as Porphyromonas asaccharolytica comb. nov., Porphyromonas gingivalis comb. nov., and Porphyromonas endodontalis comb. nov., respectively.In Bergey 's Manual of Determinative Bacteriology, 8th ed. (12), the asaccharolytic, pigmented Bacteroides were regarded as a single homogeneous taxon, Bacteroides melaninogenicus subsp. asaccharolyticus. As the clinical significance of these microorganisms in oral cavities was recognized, extensive taxonomic studies were carried out. Heterogeneity was first demonstrated among these bacteria through studies of their deoxyribonucleic acid (DNA) base compositions and enzyme polymorphism, and two regions of variation were reported (29). These findings were substantiated by sodium dodecyl sulfate polypeptide patterns (34) and DNA-DNA hybridization data (36). As a result of these studies on the asaccharolytic, pigmented strains, the group containing strains with high guanine-plus-cytosine (G+C) contents (52 to 54 mol%) and an electrophoretically fastmigrating malate dehydrogenase (MDH) was reclassified as a new species, Bacteroides asaccharolyticus (7, 29). Further differences between B. asaccharolyticus and the group of strains with low G+C contents (46 to 48 mol%) and a slow-migrating MDH (29) were revealed by an analysis of tlheir lipids (26). Strains of B. asaccharolyticus possess very high levels of 13-methyl-tetradecanoic acid (iso-C,,,, acid) and menaquinones with 10 isoprene units (MK-lo), whereas tlhe group of strains with low G+C contents contains significantly lower levels of iso-C,,:, fatty acids and menaquinones with nine isoprene units (MK-9) (26). The latter group of strains was subsequently reclassified as Bacteroides gingivalis (4). It is generally believed that most oral, asaccharolytic, black-pigmented Bacteroides strains belong to B. gingivalis, whereas most nonoral or clinical isolates are B. asaccharolyticus strains. Recently, a third asaccharolytic species, Bacteroides endodontalis, which was isolated from infected dental root canals, has been proposed (37). Phenotypically, B. endodontalis appears to be more closely related to B. asaccharolyticus than to B. gingivalis and possesses a DNA base composition of ca. 50 to 51 mol% G+C (37). The MDH of B. endodontalis migrates faster than the MDHs of B. asaccharolyticus and B. gingivalis (Shah, unpublished data).B. asaccharolyticus, B. gingivalis, and B. en...

Bacteroides: the Good, the Bad, and the Nitty-Gritty

“…In 1989 to 1990, the species within Bacteroides were restricted to members of the B. fragilis group (241), and most of the clinically relevant species that were not retained in the genus Bacteroides were placed in the genus Porphyromonas (242) or Prevotella (240). Bacteroides gracilis, which is often involved in deep-seated infections (126), was moved to the genus Campylobacter and renamed Campylobacter gracilis (286).…”

Phylogenetic analysis of genus Marinilabilia and related bacteria based on the amino acid sequences of GyrB and emended description of Marinilabilia salmonicolor with Marinilabilia agarovorans as its subjective synonym

“…The CytophagaFlavobacterium-Bacteroides (CFB) group currently represents one of eleven phyla of bacteria (Olsen & Woese, 1993 ;Woese, 1987). Phylogenetic studies that have used 16s rRNA sequences, chemotaxonomic studies and other phenotype analyses have resulted in several taxa of the CFB complex being rearranged (Bernardet et al, 1996;Nakagawa & Yamasato, 1996;Nakagawa et al, 1997;Segers et al, 1993;Shah & Collins, 1988;Steyn et al, 1998).…”

Petrimonas sulfuriphila gen. nov., sp. nov., a mesophilic fermentative bacterium isolated from a biodegraded oil reservoir

“…In the latest edition of Bergey's Manual of Systematic Bacteriology, this phylum is referred as the phylum 'Bacteroidetes', and is divided into three classes, the 'Bacteroidetes', the 'Flavobacteria' and the 'Sphingobacteria' (Garrity & Holt, 2001). The genus Bacteroides and phylogenetically closely related members of genera Porphyromonas, Dysgonomonas and Tannerella are strictly anaerobic, Gram-negative, chemoheterotrophic bacteria that have been predominantly isolated from oral cavities, the gastrointestinal tract and rumen of warm-blooded animals and other body cavities of humans and animals (Shah & Collins, 1988Hofstad et al, 2000;Sakamoto et al, 2002). We isolated a mesophilic fermentative sulfur-reducing bacterium affiliated to the phylum 'Bacteroidetes' from a biodegraded oil reservoir in Canada.…”