Bacteroides ureolyticus (NTU) medium for the selective recovery of Bacteroides gracilis.

Bacteroides gracilis is a gram-negative anaerobic bacillus which requires formate and fumarate for growth; it has been implicated in periodontal disease and serious infections of the head and neck. In this study, Bacteroides ureolyticus (NTU) medium was tested for its ability to allow the growth of B. gracilis and other formate-fumarate requiring gram-negative anaerobes and to enable the recovery of these organisms from clinical specimens. All reference strains grew on NTU medium with the exception of Wolinella recta and formate-fumarate requiring organisms were isolated from 18 of 20 samples of subgingival dental plaque from patients with chronic periodontitis. B. gracilis was the commonest species isolated (14 of the 29 isolates); B. ureolyticus was not found.

Comparison of identification methods for oral asaccharolytic Eubacterium species.

Thirty one strains of oral, asaccharolytic Eubacterium spp. and the type strains of E. brachy, E. nodatum and E. timidum were subjected to three identification techniques--protein-profile analysis, determination of metabolic end-products, and the API ATB32A identification kit. Five clusters were obtained from numerical analysis of protein profiles and excellent correlations were seen with the other two methods. Protein profiles alone allowed unequivocal identification.

A rapid, semi-automated SDS-PAGE identification system for oral anaerobic bacteria.

SDS-polyacrylamide gel electrophoresis is a useful technique in bacterial differentiation and identification. A rapid, semi-automated SDS-PAGE system (Phast System) was assessed for identification of formate-fumarate-requiring, asaccharolytic, Gram-negative oral anaerobes. The system permitted loading, separation and staining of gels within 2 h. Percentage similarities between strains were determined using correlation coefficients and cluster analysis. The protein profiles were sufficiently reproducible provided that distorted profiles were disregarded. Strains were successfully separated into their species, with the exception of Bacteroides ureolyticus NCTC 10939, which appeared to be distinct from other strains of that species. Twenty-nine unidentified formate-fumarate-requiring, sub-gingival plaque strains were suitably clustered with the standard strains as verified by a series of physiological and biochemical tests.

The antibacterial and anti-staining properties of the novel anti-adherent agent M239, 144 alone and in combination with chlorhexidine.

The anti-adherent agent M239,144 has been shown to reduce the adhesion of S. sanguis strains to saliva-coated hydroxyapatite by 27-94%. The purpose of this study was to determine any antibacterial properties of M239,144 which might inhibit replication of the organisms which do adhere and to determine whether M239,144 interferes with the antibacterial properties of the antiseptic agent chlorhexidine. Maximum inhibitory dilutions (MIDs) were calculated using both broth and agar methods. 0.1% M239,144 displayed no antibacterial activity against S. oralis NCTC 7864 or S. sanguis NCTC 7863 using the broth dilution method and had no antibacterial activity against a range of plaque-forming organisms using the agar dilution method. The anti-bacterial activity of chlorhexidine against four of five oral plaque-forming species was reduced by 0.1% M239,144. The effect of a novel anti-adherent agent, MK239,144, on chlorhexidine staining was assessed in an in vitro model. 1% M239,144 completely prevented chlorhexidine staining at concentrations from 0.0002% to 0.2%. M239,144/chlorhexidine formulations show potential for a non-staining anti-plaque mouthwash.