Bacteroides Distasonis Research Articles

Characterization of three different beta-lactamases from the Bacteroides fragilis group.

beta-Lactamases from five strains of Bacteroides fragilis and two strains of Bacteroides uniformis, all resistant to beta-lactam antibiotics, were compared by means of isoelectric focusing and enzyme kinetic measurements. beta-Lactamases from the five B. fragilis strains were identical, whereas those from the two B. uniformis strains were distinguished from each other and also from the B. fragilis enzymes. The two B. uniformis strains were relatively resistant to cefoxitin (minimal inhibitory concentration, 32 micrograms/ml), but only one of the strains, B. uniformis 2986, was found to rapidly inactivate cefoxitin. This apparently enzymatic inactivation of cefoxitin seemed to be of minor importance, and the main factor for cefoxitin resistance was considered to be a decreased permeability of the drug. Transfer of resistance to beta-lactam antibiotics from these beta-lactamase-producing strains of B. fragilis and B. uniformis to a non-beta-lactamase-producing strain of Bacteroides distasonis was attempted, but with these isolates no transfer of resistance to beta-lactam antibiotics was demonstrated.

Purification of a mucopolysacharidase from Bacteroides distasonis.

A mucopolysaccharidase derived from a pathogenic strain of Bacteroides distasonis was isolated and purified by fractionation with cold acetone and ion-exchange chromatography on DEAE-cellulose, pH 8.0. Three detectable enzyme activities from concentrated supernatant filtrates were obtained in a fraction precipitated by three volumes of cold acetone; these were DNAase, hyaluronidase and chondroitinase-like activity. Separation of the DNAase was achieved by ion-exchange chromatography. Fractions designated as purified mucopolysaccharidase contained both hyaluronidase and chondroitinase-like activity.

Cefamandole therapy of endomyometritis following cesarean section

Sixty women with endometritis following cesarean section were treated with cefamandole (12 gm/day) alone. Specimens for culture were obtained by endometrial lavage and from peripheral blood. Minimum inhibitory concentrations were performed on anaerobes and enterococci by an agar dilution technique. Anaerobic organisms were isolated in 55 of 60 (91.7%) endometrial specimens. Bacteremia was documented in 12 patients (20%). Of 387 isolates from uterine cultures, 20 (5%) were resistant or had MIC's ≥ 32 μg/ml. Ten patients (17%) were judged clinical failures and responded to additional antibiotics. Of 19 patients with Bacteroides fragilis or related species∗∗Organisms designated Bacteriodes fragilis are widely recognized for their resistance to many antibiotics and their frequent occurrence in pelvic and abdominal infections. In 1976, four organisms previously accorded subspecies rank in the species Bacteroides fragilis were re-ranked as species of the genus Bacteroides. Thus Bacteroides fragilis subspecies thetaiotaomicron became Bacteroides thetaiotaomicron: Bacteroides fragilis subspecies vulgatis became Bacteroides vulgatis. Bacteroides fragilis subspecies distasonis became Bacteroides distasonis, and Bacteroides fragilis subspecies ovatus became Bacteroides ovatus (Cato, E. P. and Johnson, J. L.: Int. J. System. Bacteriol. 26:230. 1976). The expression “Bacteroides fragilis or related species” as used here refers to organisms identified as Bacteroides fragilis or any of the other four reinstated species. isolates in the uterus, three (15%) were judged as failures. Cefamandole was well tolerated and appears to be useful in the initial treatment of endomyometritis.

Protective Efficacy of Immunization with Capsular Antigen against Experimental Infection with Bacteroides fragilis

The protective efficacy afforded by immunization with the capsular antigen of Bacteroides fragilis against abscess formation and bacteremia due to this organism was studied in an experimental rat model of intraabdominal sepsis. Of unimmunized animals, animals immunized with methylated bovine serum albumin and complete Freund's adjuvant, and animals immunized with lipopolysaccharide of Bacteroides thetaiotaomicron, greater than 90% developed abscesses when challenged intraperitoneally with strains of B. fragilis or Bacteroides distasonis (given with an enterococcus) or with the cecal contents of meat-fed rats. In contrast, animals immunized with B. fragilis capsular polysaccharide, given with or without methylated bovine serum albumin and complete Freund's adjuvant, and animals immunized with the outer membrane of B. fragilis strain 23745 were protected to a significant degree from abscesses caused by challenge with B. fragilis or B. distasonis. Such immunization had no overall effect on the development of abscesses in animals challenged with the entire cecal contents of meat-fed rats; however, B. fragilis was eliminated from the abscesses of these animals. Animals immunized with the capsular polysaccharide were protected from early B. fragilis bacteremia.

Synthesis of alpha-ketoglutarate by reductive carboxylation of succinate in Veillonella, Selenomonas, and Bacteriodes species.

Evidence for reductive carboxylation of succinate to synthesize alpha-ketoglutarate was sought in anaerobic heterotrophs from the rumen and from other anaerobic habitats. Cultures were grown in media containing unlabeled energy substrates plus [14C]succinate, and synthesis of cellular glutamate with a much higher specific activity than that of cellular asparate was taken as evidence for alpha-ketoglutarate synthase activity. Our results indicate alpha-ketoglutarate synthase functions in Selenomonas ruminantium, Veillonella alcalescens, Bacteroides fragilis, Bacteroides vulgatus, Bacteroides uniformis, Bacteroides distasonis, and Bacteroides multiacidus. Evidence for this carboxylation was not found in strains representative of 10 other species.

Superoxide dismutase in Bacteroides fragilis and related Bacteroides species

Superoxide dismutase (SOD) activity was demonstrated in cell-free extracts of Bacteroides fragilis, Bacteroides vulgatus, Bacteroides distasonis, Bacteroides ovatus, and Bacteroides thetaiotaomicron. The strains were grown under anaerobic conditions in Trypticase soy broth, and the specific activity of SOD in the extracts was, in most strains, higher than in cell-free extracts of Escherichia coli B grown under anaerobic conditions. Isoelectric focusing of the extracts in polyacrylamide gel demonstrated distinct forms of SOD in the different species.

Laminarinase (beta-glucanase) activity in Bacteroides from the human colon.

Laminarin, a beta(1 leads to 3)-glucan similar to those found in plant cell walls, is fermented by some species of anaerobic bacteria from the human colon. Laminarinase (EC 3.2.1.6) and beta-glucosidase (EC 3.2.1.21) activities were determined in strains representing Bacteroides thetaiotaomicron, Bacteroides distasonis, and an unnamed deoxyribonucleic acid homology group of Bacteroides fragilis. In all three species, laminarinase activity was inducible by laminarin and was predominantly cell bound. The products of laminarinase activity varied with each species. In the case of B. thetaiotaomicron, the major product of laminarin hydrolysis was glucose (70 to 90%), and there were small amounts of laminaribiose (G2) and oligomers of glucose as high as G4. In the case of group '0061-1,' glucose (40 to 50%) and oligomers of glucose as high as G6 were found. The laminarinase of B. distasonis differed from the laminarinases of the other two species in that it mainly produced oligomers of glucose (G2-G5). beta-Glucosidase activity was also found in all three species. beta-Glucosidase was induced by glucose-containing disaccharides as well as by laminarin. The beta-glucosidases of the three Bacteroides species differed with respect to level of activity, induction pattern, and sensitivity to inhibition by D-glucono-1,5-lactone.

Production and some properties of catalase and superoxide dismutase from the anaerobe Bacteroides distasonis.

The catalase level of Bacteroides distasonis (ATCC 8503, type strain) varied with the amount of hemin supplied to the medium when the cells were grown in either a prereduced medium containing 0.5% peptone, 0.5% yeast extract, and 1% glucose or in a prereduced, defined heme-deficient medium. The effect of hemin on catalase production could not be duplicated by ferrous sulfate or ferrous ammonium citrate. Catalase activity reached peak values in late log phase, whereas superoxide dismutase specific activity remained constant throughout the culture growth cycle. The catalase was a nondialyzable, cyanide and azide-sensitive, heat-labile protein that coeluted with bovine erythrocyte catalase from Sepharose 6 B. Analysis of polyacrylamide gels stained for catalase activity and for heme showed a correspondence between the single catalytic activity band and one of three heme-protein bands. These data suggest a heme-protein of approximately 250,000 molecular weight. The superoxide dismutase was a cyanide-insensitive protein of approximately 40,000 molecular weight that migrated electrophoretically on acrylamide gels as a single band of activity.