The Isolation and Identification of Bacteroides Spp. From the Normal Human Gingival Flora

Abstract

(1972) was followed in all essential aspects; incubation was at 37°C in an atmosphere of H2 90% and COZ 10%. A slope of Simmons citrate medium seeded with Pseudomonas aeruginosa was included in each jar as a control.Specimens. Sterile toothpicks were used to collect samples of subgingival plaque from 20 normal healthy adults. The subjects were medical students aged 19-20 years; none had any gross oral or dental pathology and none was receiving antibiotic therapy.Isolation of Bacteroides. The methods and media were derived from those of Baird-Parker (1957), Loesche, Hockett and Syed (1971), Syed and Loesche (1973) and Williams et al. (1975); they were evaluated by Holbrook (1976) and Holbrook et al. (1978). The samples of plaque were seeded directly on to a sector of a plate of pre-reduced BM agar (see Williams et al., 1975) with kanamycin 75 pg/ml and vancomycin 2.5 pg/ml and the inoculum was streaked over the remainder of the plate. The plates were examined after anaerobic incubation for 48 h; all colony types were noted and representative colonies were subcultured from each specimen on to plain BM agar. After incubation for a further 48 h, any additional colony types were noted and further representative colonies were subcultured to a total of 10 from each specimen. The colony types were selected in approximate proportions to their comparative numbers on the primary isolation plate. The isolates were suspended in a freezing medium of Nutrient Broth No. 2 (Oxoid) with inactivated horse serum (Wellcome) 10% and glucose 1% and held at -70°C in a liquid-nitrogen container.IdentiJcation of isolates. The isolates were identified by the methods of Duerden et af. (1976, 1980). The tests were: colony morphology after 48-h incubation on blood agar; cell morphology in gram-stained smears from 48-h cultures on blood agar and in BM broth with cooked-meat particles (see Deacon, Duerden and Holbrook, 1978); pigment production on BM agar; haemolysis on human blood agar; motility in BM broth; antibiotic-disk resistance tests with neomycin 1000 pg, kanamycin 1000 pg, penicillin 2 units and rifampicin 15 pg disks; tolerance tests with taurocholate, deoxycholate, Victoria blue 4R and ethyl violet; biochemical tests for the production of indole, digestion of gelatin and hydrolysis of aesculin; fermentation tests with glucose, lactose, sucrose, rhamnose, trehalose, mannitol and xylose.

The Isolation and Identification of Bacteroides Spp. From the Normal Human Vaginal Flora

“…The common vaginal species were, however, similar to the oral species isolated from subgingival plaque; in a parallel study (Duerden, 1980b) the commonest oral species were B. oralis, B. melainogenicus ss. melaninogenicus and ss.…”

Adaptation of Porphyromonas gingivalis to microaerophilic conditions involves increased consumption of formate and reduced utilization of lactate

“…1) thus revealed no drastic differences in growth dynamics of P. gingivalis, indicating that this bacterium can grow nearly equally under both conditions. This is noteworthy, given that this organism is classified as a strictly anaerobic bacterium and that exclusively anaerobic conditions are recommended to grow the organism (Duerden, 1980;Loesche et al, 1992). Our laboratory and previous studies have demonstrated that P. gingivalis can withstand prolonged exposure to oxygen; thus, clinical samples predicted to contain this bacterium can be stored for a short time in the presence of low concentrations of oxygen.…”

Pathogenic Potential of Campylobacter ureolyticus

“…High levels of toxin lyses cells as the pores formed by the toxin allow cytoplasmic contents to leak out (24). Of interest was the identification of a hypothetical protein belonging to Bacteroides eggerthii, a member of the Bacteroides genus that has been isolated from human feces (3,13). The relevance of identifying this protein from C. ureolyticus was that the bacterium was previously a member of the Bacteroides genus.…”