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At least 109 records · Page 6Linked to original sources
PubMed1987

Transposition of Tn4551 in Bacteroides fragilis: identification and properties of a new transposon from Bacteroides spp.

Tn4551, a clindamycin resistance (Ccr) transposon from the R plasmid pBI136, was cloned onto an Escherichia coli-Bacteroides shuttle vector which could replicate normally in E. coli but was maintained unstably in Bacteroides fragilis. To aid in cloning and to ensure maintenance of Tn4551 in E. coli, a kanamycin resistance determinant (Kmr) was inserted in the transposon. The transposon-bearing shuttle vector pFD197 was transformed into B. fragilis 638, and putative insertions of Tn4551::Kmr were identified by screening for resistance to clindamycin and plasmid content. Southern hybridization analyses were used to verify integration of the transposon in the B. fragilis chromosome, and the frequency of insertion was estimated at 7.8 X 10(-5) events per generation. In 57% of the isolates tested a second integration event also occurred. This second insertion apparently involved just a single copy of the 1.2-kilobase repeat sequence which flanks the transposon. In addition, Tn4551::Kmr appeared to function as a transposon in E. coli. Evidence for this was obtained by the isolation of transposon insertions into the bacteriophage P1 genome. Finally, the transposon vector, pFD197, could be mobilized to other B. fragilis strains in which transposition was detected. Mobilization from the strain 638 background was via a conjugation like process, but occurred in the absence of known conjugative elements or other detectable plasmids. This result suggested the presence of a host-encoded transfer system in this B. fragilis strain.

Bacteroides fragilis↗
PubMed1980

Evaluation of Fluoretec-M for detection of oral strains of Bacteroides asaccharolyticus and Bacteroides melaninogenicus.

Fluoretec-M is a polyvalent conjugate used in direct fluorescent-antibody staining for identification of the Bacteroides asaccharolyticus-Bacteroides melaninogenicus group. The Fluoretec-M reagent detected all oral and nonoral test strains of B. melaninogaenicus subsp. intermedius, all test strains of B. melaninogenicus subsp. melaninogenicus, and the nonoral strains of B. asaccharolyticus. However, the Fluoretec-M polyvalent reagent and the monovalent conjugates which constitute Fluoretec-M did not detect the oral strains B. asaccharolyticus. The use of Fluoretec-M can therefore generate false-negative results in studies of specimens from oral cavity and from nonoral sites in which an infection with B. asacacharolyticus of oral origin may have taken place. It is suggested that antibodies reactive with the oral antigenic type of B. asaccharolyticus be included in the preparative procedure of the Fluoretec-M reagent.

Bacteroides↗
PubMed1992

Cytochrome composition and oxygen-dependent respiration-driven proton translocation in Wolinella curva, Wolinella recta, Bacteroides ureolyticus, and Bacteroides gracilis.

The membrane fractions of the microaerobically grown type strains of Wolinella curva, Wolinella recta, Bacteroides ureolyticus, and Bacteroides gracilis contained membrane-bound cytochrome b, cytochrome c, and CO-binding cytochrome c. Soluble cytochrome c and CO-binding cytochrome c were also present. Although B. gracilis is oxidase negative, it possessed cytochrome c. With H2 or formate as the electron donor, proton efflux from anaerobic cells occurred upon addition of a pulse of oxygen. With formate as the electron donor, the H+/O ratios of W. curva, W. recta, B. ureolyticus, and B. gracilis were 0.75, 1.66, 2.06, and 2.04, respectively. With H2 as the electron donor, the H+/O ratios of W. curva, B. ureolyticus, and B. gracilis were 1.25, 1.97, and 2.36, respectively. Proton translocation was inhibited by the protonophore carbonylcyanide m-chlorophenylhydrazone. The results confirm that the organisms are not anaerobes but are microaerophiles capable of respiring with oxygen.

Bacteroides↗
PubMed1988

Comparison of cultural methods and DNA probe analyses for the detection of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, and Bacteroides intermedius in subgingival plaque samples.

The purpose of this study was to compare DNA probe analyses to cultural methods for detecting three periodontal pathogens, Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, and Bacteroides intermedius, in human subgingival plaque. Subgingival sites from patients diagnosed as either healthy or showing evidence of gingivitis or juvenile or adult periodontitis were sampled using two paper points. The number of these pathogens from one paper point was determined using microbiologic media and speciated by biochemical tests. Results were then compared to bacterial numbers obtained from the other paper point using species-specific DNA probes. In 60 samples from the disease group, DNA probe analysis demonstrated 100% effectiveness in detecting A. actinomycetemcomitans and B. intermedius and 91% effectiveness in detecting B. gingivalis at culture positive levels (greater than or equal to 10(3) cells). In addition, probe assays frequently identified these pathogens in samples that were culture negative. Probe analysis revealed a better correlation between presence of a pathogen and clinical evidence of disease on an individual patient basis. In contrast, most samples taken from sites of healthy individuals showed undetectable levels of all three pathogens as determined by both techniques. These results suggest that DNA probe technology is at least equivalent and often superior to cultural methods for detecting A. actinomycetemcomitans, B. gingivalis, and B. intermedius in human subgingival plaque samples.

Actinobacillus↗
PubMed1990

Stimulation of lymphocytes in vitro by Bacteroides intermedius and Bacteroides (Porphyromonas) gingivalis sonicates.

The present study was designed to assess whether the in vitro stimulation of lymphocytes by sonicates of Bacteroides intermedius and Bacteroides (Porphyromonas) gingivalis is antigen specific or non-specific. In addition, the role of T and B lymphocytes in these responses was assessed. Peripheral blood lymphocytes obtained from healthy volunteers were cultured in the presence of these bacterial preparations and the proliferative response was measured. In similar experiments the response of umbilical cord blood lymphocytes did not exceed background values. In limiting dilution experiments only 1:4000, 1:6800, and 1:8200 of the lymphocytes initially reacted to B. intermedius, which strongly argues for the antigen-specificity of the response. Purified T cells, in the presence of monocytes, proliferated when stimulated with B. intermedius and B. gingivalis. As for B cell stimulation, the bacterial extracts were capable of inducing IgM production, which appeared to be T cell dependent. These findings support the notion that B. intermedius and B. gingivalis induce specific T cell activation; secondarily, a T cell dependent, polyclonal B cell activation may occur.

Adult↗
PubMed1988

Proteolysis of alcohol-treated soybean meal proteins by Bacteroides ruminicola, Bacteroides amylophilus, pepsin, trypsin, and in the rumen of steers.

Sodium dodecyl sulfate-gel electrophoresis and cation exchange chromatography were used to examine degradation of treated and untreated soybean meal protein fractions by Bacteroides amylophilus H18(1), Bacteroides ruminicola B(1)4, pepsin, trypsin, and intraruminally. Soybean meal treatments consisted of 30% vol/vol isopropanol, 40% propanol, or 50% ethanol at 22 degrees C or 70% ethanol at 80 degrees C. Water-soluble protein fractions were applied to a hydroxylapatite column and eluted with a discontinuous phosphate gradient of .03 to .27 and then .27 to 1.0 M. The four protein fractions with the highest absorbance at 276 nm were dialyzed against distilled water prior to being subjected to enzymatic hydrolysis. Soybean meal treated with 40% propanol had the greatest reduction in absorbance of all effluents at 275 nm, followed by soybean meal treated with 50% ethanol or 30% isopropanol. Comparison of electrophoretic patterns over time showed that B. amylophilus H18(1), degraded protein subunits more rapidly than B. ruminicola B(1)4. Protein subunits with the highest molecular weights were the most rapidly degraded by B. amylophilus H18(1), B. ruminicola B(1)4, pepsin, and trypsin. Hydroxylapatite chromatography of omasal fluid from steers supplemented with untreated soybean meal or soybean meal treated with 70% ethanol at 80 degrees C indicated that no detectable soluble glycinin or conglycinin escaped ruminal degradation.

Animals↗
PubMed1990

[The in vitro sensitivity of Bacteroides gingivalis and Bacteroides intermedius to different classes of antibiotic chemical molecules].

A study was carried out to assess the in vitro sensitivity of Bacteroides gingivalis and Bacteroides intermedius to various classes of chemio-antibiotic molecules. The activities of two cephalosporins (cefuroxime and cefotaxime), which have never previously been used for periodontal therapy, were also evaluated. Results showed that the cephalosporins possessed an equal or greater inhibitory activity against the bacteria studied than traditional tetracyclines, and a greater inhibitory activity than other antibiotics studied (metronidazole, ampicillin, piperacillin). Further studies are required to assess in vivo efficacy of cephalosporin therapy in severe periodontal diseases.

Adult↗
PubMed1987

Activity of newer beta-lactam agents against clinical isolates of Bacteroides fragilis and other Bacteroides species.

The in vitro activities of beta-lactam antibiotics against Bacteroides fragilis and B. fragilis group isolates are presented. Clinical isolates from 1986 were compared with strains from 1979 to 1982. Imipenem, ticarcillin-clavulanic acid, and ceftizoxime were the most active agents. Cefotetan was equivalent to cefoxitin against B. fragilis but less active against B. fragilis group isolates. Enhancement of cefotaxime by its desacetyl metabolite was minimal.

Anti-Bacterial Agents↗
PubMed1979

Fluorescent antibody test kit for rapid detection and identification of members of the Bacteroides fragilis and Bacteroides melaninogenicus groups in clinical specimens.

The Fluoretec fluorescent antibody test kit (Pfizer Inc., New York, N.Y.), developed for the rapid detection of members of the Bacteroides fragilis and B. melaninogenicus groups, was evaluated by testing 58 stock cultures and 76 clinical specimens. The test reagents detected 100% of 40 B. fragilis and B. thetaiotaomicron stock culture strains, although only 22% of 18 B. vulgatus, B. distasonis, and B. ovatus strains showed positive fluorescence. The 76 clinical specimens were evaluated by examining fluorescent antibody-stained smears of 49 specimens of purulent material and smears of 27 blood cultures which were positive for gram-negative bacilli by Gram stain or subculture. The fluoretec reagent detected members of the B. fragilis group in 28 (97%) of the 29 specimens of purulent material and all (100%) of the 16 blood cultures in which these anaerobes were demonstrated by culture. Overall, the Fluoretec reagent detected members of B. fragilis group in 44 (98%) of the 45 clinical specimens which were shown by culture to contain these anaerobes. Two of the 76 clinical specimens gave positive fluorescence for members of the B. fragilis group but failed to yield these organisms by culture. Members of the B. melaninogenicus group were detected by culture in 15 specimens and in each case their presence was demonstrated by the Fluoretec reagent. No members of the B. melaninogenicus group were isolated from five clinical specimens that gave positive fluorescence with the B. melaninogenicus reagent.

Anaerobiosis↗
PubMed1995

Bacteroides fragilis adheres to laminin significantly stronger than Bacteroides thetaiotaomicron and other species of the genus.

The laminin binding properties of eight species of the genus Bacteroides were examined using latex particle agglutination assay. B. fragilis was found to bind strongly to laminin, whereas all other species tested showed no or only weak laminin adherence. The pronounced differences in laminin binding activity between B. fragilis on the one side and B. thetaiotaomicron and B. ovatus on the other were determined to be statistically significant (p < 0.001 and p < 0.01, respectively). With regard to the relevance of laminin adherence for bacterial pathogenicity and invasiveness, our results give a possible explanation for the well-known finding that B. fragilis is the most frequently isolated pathogen in anaerobic bacteremia.

Bacterial Adhesion↗
PubMed1997

Use of polymerase chain reaction fingerprinting to compare clinical isolates of Bacteroides fragilis and Bacteroides thetaiotaomicron from Germany and the United States.

Accurate identification of Bacteroides species is often problematic. Therefore, we used a polymerase chain reaction (PCR) fingerprinting technique with either a single nonspecific primer derived from tDNA intergenic spacer or a single primer that anneals to mini- and microsatellite DNA sequences to compare 34 clinical isolates of B. fragilis and 21 clinical isolates of B. thetaiotaomicron from Southern California with 32 clinical isolates of B. fragilis and 10 isolates of B. thetaiotaomicron from Germany. All German B. fragilis isolates (32 of 32) formed one PCR fingerprint group that matched the PCR profile of the B, fragilis reference strain ATCC (American Type Culture Collection) 25285, representative of DNA homology group I. In contrast, the isolates from Southern California formed two PCR fingerprint groups. Although most of these strains (29 of 34) also matched B. fragilis ATCC 25285, some strains (4 of 34) matched the DNA homology group II reference strain VPI (Virginia Polytechnic Institute) 2393. One of the 34 strains showed a unique profile. German B. thetaiotaomicron strains (10 of 10) formed one PCR fingerprint group, matching the reference strain B. thetaiotaomicron ATCC 29742, whereas the B. thetaiotaomicron isolates from Southern California showed heterogenous profiles.

Bacteroides↗
PubMed1985

In-vivo bactericidal activity of Sch 34343 in Bacteroides fragilis abscesses and in Bacteroides fragilis-Escherichia coli abscesses.

Bacteroides fragilis pure-culture abscesses and Bact. fragilis-Escherichia coli mixed-culture abscesses were initiated subcutaneously in mice and intraperitoneally in rats. Within 1 h after injection of Sch 34343, the drug was present in higher concentrations in the abscesses than in the blood of infected animals. After five days of Sch 34343 therapy with either 100 or 400 mg/kg administered five times a day to mice with subcutaneous abscesses, the numbers of Bact. fragilis in pus decreased approximately three log-fold, reflecting a killing of 99.99% of the viable Bact. fragilis, while the numbers of E. coli decreased approximately 0.5 log-fold, reflecting a killing of 50% of the viable E. coli. After five days of therapy with either 50 or 150 mg/kg administered five times a day to rats with intraperitoneal fibrin clot abscesses, the viable Bact. fragilis again decreased three log-fold; the viable E. coli decreased one log-fold in rats given the higher dosages of the drug. Sch 34343 is a promising agent for the treatment of anaerobic infections because it can penetrate into anaerobic abscesses and can kill large numbers of bacteria within abscesses.

Abscess↗
PubMed1985

Experimental Bacteroides fragilis bacteremia in a primate model: evidence that Bacteroides fragilis does not promote the septic shock syndrome.

Experimental Bacteroides fragilis bacteremia was studied in subhuman primates. Following intravenous infusion of viable B. fragilis there was an exponential clearance of organisms from the bloodstream. The major clearance organ was the liver, which accumulated 68.2% of the total inoculum. The most efficient clearance was exhibited by the spleen, with uptake of 1.16% gm tissue. Hemodynamic studies revealed no significant changes in heart rate, mean arterial pressure, or cardiac output following B. fragilis infusion. Complement activity as measured by CH50, alternative pathway hemolytic activity, granulocyte aggregometry, C4, C3, properdin, and Factor B levels were similarly unaffected by infusion of B. fragilis. In contrast, profound hemodynamic changes and a consistent decrease in complement activity was noted after challenge with S. minnesota. The results of this study suggest that B. fragilis bacteremia has a minor role in producing the acute hemodynamic changes associated with the septic shock syndrome.

Animals↗
PubMed1982

Cytotoxic activity of Bacteroides gingivalis and Bacteroides asaccharolyticus.

Culture filtrates of all eight strains of Bacteroides gingivalis and all five strains of B. asaccharolyticus were toxic for Vero cells. Cytotoxicity was in general greater with material from cultures of B. gingivalis than from B. asaccharolyticus but none of the culture filtrates from eight strains of B. melaninogenicus showed activity in this test. The toxic material was released during prolonged incubation and more detailed study of preparations from one strain indicated that it had a molecular weight of less than 3500 and was heat stable.

Animals↗
PubMed1989

Immunochemistry of the cell surfaces of Bacteroides bivius and Bacteroides disiens.

Outer membranes were extracted from seven strains of Bacteroides bivius and six strains of B. disiens by the Sarkosyl method. Lipopolysaccharides (LPS) were extracted from the same strains by the Proteinase K method, and from three strains of each species by an aqueous phenol method. Analysis of the outer-membrane proteins by SDS-PAGE demonstrated that, within a species, very similar patterns with many shared or common bands were produced, but there were sufficient differences between species to allow separation. Immunoblotting with antisera raised against whole cells of each of the type strains showed that many antigens were shared between species. Smooth LPS was present in both species. By immunoblotting, the O-antigen of B. disiens was shown to be common to all six strains, and there was no cross-reaction between the B. disiens antiserum and B. bivius LPS. The O-antigen of B. bivius was not detected by immunoblotting with homologous antiserum, but antiserum to B. bivius reacted with a series of common low molecular mass antigens that were present in LPS preparations from strains of both species.

Bacterial Outer Membrane Proteins↗
PubMed1985

Comparative evaluation of the 2-methyl-5-nitroimidazole compounds dimetridazole, metronidazole, secnidazole, ornidazole, tinidazole, carnidazole, and panidazole against Bacteroides fragilis and other bacteria of the Bacteroides fragilis group.

Tube-dilution MICs of seven 2-methyl-5-nitroimidazole compounds varying at the 1-substitution were determined against Bacteroides fragilis. Activities on a molar basis were ranked: tinidazole greater than panidazole greater than ornidazole greater than metronidazole greater than or equal to secnidazole greater than carnidazole greater than dimetridazole. Geometric mean MICs varied from 0.5 to 6.6 microM, and MICs against individual strains varied up to 50-fold between compounds. In general, the MIC of each drug correlated with that of each of the other drugs, but with tinidazole the correlation coefficients tended to be small and were not significant versus metronidazole and secnidazole. MICs against 14 other bacteria of the B. fragilis group, including B. distasonis, B. ovatus, B. thetaiotaomicron, B. uniformis, and B. vulgatus, were within the range determined for B. fragilis.

Antifungal Agents↗
PubMed1988

Activities of Nigerian chewing stick extracts against Bacteroides gingivalis and Bacteroides melaninogenicus.

The in vitro activities of extracts of Nigerian chewing sticks against Bacteroides gingivalis and B. melaninogenicus are presented. The greatest inhibitory action was produced by Serindeia werneckei, whereas Fagara zanthoxyloides produced no appreciable inhibitory effect. A generally good correlation was found between the killing curves and MICs. Only extracts of Anogeissus leiocarpus showed acute toxicity in mice.

Animals↗
PubMed1996

Use of a modified Bacteroides-Prevotella shuttle vector to transfer a reconstructed beta-1,4-D-endoglucanase gene into Bacteroides uniformis and Prevotella ruminicola B(1)4.

A carboxymethyl cellulase (CMCase) gene from Prevotella ruminicola B(1)4 was reconstructed by adding a cellulose binding domain from a Thermomonospora fusca cellulase and was conjugally transferred from Escherichia coli to Bacteroides uniformis 0061 by using a chloramphenicol and tetracycline resistance shuttle vector (pTC-COW). pTC-COW was specifically constructed to facilitate conjugal transfer of vectors from B. uniformis donors to P. ruminicola recipients. B. uniformis transconjugants containing CMCase constructs cloned into pTC-COW expressed Cmr, but they did not produce the reconstructed CMCase until a xylanase promoter from P. ruminicola 23 was added upstream of the CMCase (pTC-XRCMC). The xylanase promoter allowed the B. uniformis transconjugants to produce large amounts of the reconstructed CMCase, which was present on the outside surface of the cells. Although the reconstructed CMCase alone did not allow B. uniformis to grow on acid-swollen cellulose, rapid growth was observed when two exocellulases were added to the culture supernatant. Under these conditions, the reconstructed CMCase permitted faster growth than the wild-type CMCase. The frequency of transfer of pTC-XRCMC from B. uniformis to P. ruminicola B(1)4 was increased 100-fold when strictly anaerobic conditions, nitrocelluose filters (cell immobilization), and more stringent selections were employed. Although the P. ruminicola B(1)4 (pTC-XRCMC) transconjugates expressed Tcr and had DNA that hybridized with a probe to the shuttle vector, these transconjugants did not produce detectable levels of the reconstructed CMCase even when xylan was the carbon source. On the basis of these results, it appears that not all of the promoters recognized by B. uniformis and P. ruminicola 23 are functional in P. ruminicola B(1)4. However, the results with B. uniformis suggest that the introduction of a P. ruminicola B(1)4 promoter should allow expression of the reconstructed CMCase in P. ruminicola B(1)4.

Anaerobiosis↗