Bacteroides forsythus sp. nov., a Slow-Growing, Fusiform Bacteroides sp. from the Human Oral Cavity

Abstract

The characteristics of a group of slow-growing, fusiform, fastidious anaerobes isolated from advanced periodontal lesions in human oral cavities were examined. Our results indicated that 12 fusiform Bacteroides strains belong to a new species in the genus Bacteroides. The name Bacteroides forsythus is proposed for these isolates. The type strain is strain ATCC 43037.Anaerobic, gram-negative, fusiform organisms which did not resemble previously recognized speqies were isolated from deep periodontal pockets of humans that showed progressive tissue loss (3,15,17). The cells appeared to be long filaments or medium rods with tapered (fusiform) or rounded ends. Some cells had central swellings. Large spheroids were frequently associated with the cells, particularly the cells with filamentous morphology. These strictly anaerobic fusiform Bacteroides strains grew slowly on blood agar plates and grew poorly in all broth media tested and on most agar media tested. Biochemical tests gave inconsistent results and were usually negative. For this reason, the fusiform Bacteroides strains were characterized without using most of the conventional biochemical tests, Deoxyribonucleic acid (DNA) guanine-plus-cytosine (G +C) content, DNA-DNA homology, cell wall ultrastructure, serology, API enzyme substrate tests (Analytab Products, Plainview, N.Y.), and protein profiles of whole sonicated cells obtained by using polyacrylamide gel electrophoresis (PAGE) indicated that these organisms comprise a distinct species in the genus Bacteroides. The name Bacteroides forsythus is proposed for this new species.Strains and inocula. The strains which we used are listed in Table 1. These organisms were maintained on Trypticase soy agar plates supplemented with 5% sheep blood (TSBA; BBL Microbiology Systems, Cockeysville, Md.) at 35 to 37°C in an atmosphere containing 10% H2, 10% CO2, and 80% N2. The fusiform Bacteroides strains were maintained on TSBA plates; a fusiform Bacteroides strain was streaked on one-half of each plate, and a strain of Fusobacterium nucleaturn was streaked on the other half of the plate. The strains were stored in liquid nitrogen by using previously described methods (14). Inocula for tests were obtained by scraping cells from the surfaces of TSBA plates. At least 100 plates of fusiform Bacteroides strains were used to obtain sufficient cells for DNA extraction. Two to four plates were used to provide the inoculum for an enzyme-linked immunosorbent assay and for each of the tests in the API enzyme substrate test series.DNA-DNA hybridization. Cells of reference strains were grown in 2-to 3-liter broth cultures (mycoplasma broth [BBL] supplemented with 5 mg of hemin per liter) for extraction of DNA. The DNA was extracted by using a method modified (13) from the procedure of Marmur (9). G+C contents were determined by the thermal denaturation method (1). Levels of DNA-DNA homology were determined by using the initial renaturation rates (2).API enzyme substrate tests. API ZYM and API An-Ident enzymatic substrate tests were ...

Uncultivated Tannerella BU045 and BU063 are slim segmented filamentous rods of high prevalence but low abundance in inflammatory disease-associated dental plaques

“…Notably, cells detected in plaque were usually shorter than cells derived from in vitro-grown T. forsythia strains (data not shown). The morphology of the identified T. forsythia cells is in agreement with earlier descriptions by Tanner et al (1986) and Lai et al (1987), but contrasts with the description by Gersdorf et al (1993). These authors considered T. forsythia cells to be thin elongated rods, reminiscent of the uncultivable cells identified in this study.…”

“…During the last decade hundreds of previously unknown phylotypes and clones have been identified in studies investigating 16S rRNA diversity in different forms of dental plaque (Paster et al, 2001(Paster et al, , 2002Munson et al, 2004;Aas et al, 2005;Kumar et al, 2005;de Lillo et al, 2006). Among the many uncultivable human oral phylotypes two clones with an apparently supragingival habitat, BU045 and BU063, attracted some interest, because their 16S rRNA gene sequence groups them within the genus Tannerella (Paster et al, 2001;Leys et al, 2002;de Lillo et al, 2004), which otherwise contains, besides some uncultivated clones from soil, only a single species, Tannerella forsythia (also known as Tannerella forsythensis) (Tanner et al, 1986;Tanner & Izard, 2006). T. forsythia is a 'consensus periodontal pathogen ' (Haffajee & Socransky, 2006) and associated with subgingival plaque from chronic and occasionally aggressive periodontitis (see Tanner & Izard, 2006, for review) rather than periodontal health like the two clones BU045 and BU063.…”

Transfer of Bacteroides splanchnicus to Odoribacter gen. nov. as Odoribacter splanchnicus comb. nov., and description of Odoribacter denticanis sp. nov., isolated from the crevicular spaces of canine periodontitis patients

“…3b). The morphology of strain B106 T is analogous to that of T. forsythensis under the same growth conditions (Tanner et al, 1986). The morphological difference between Porphyromonas gulae B 243 and strain B106 T further supports the placement of strain B106 T outside of the genus Porphyromonas.…”

Campylobacter showae sp. nov., Isolated from the Human Oral Cavity

“…Discontinuous SDS-PAGE in a 10% separating gel and a 4% stacking gel (16 by 16 cm; thickness, 0.75 mm) was carried out with dual gels at 30 mA for 4 to 5 h (6). After electrophoresis, one of the gels was silver stained (21), and the other was soaked in a transfer buffer containing 0.1 M Tris-HC1 (pH 7.5), 0.2 M glycine, and 1% methanol for at least 30 min for subsequent electrotransfer.…”