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PubMed1998

Induction of release of tumor necrosis factor and IL-6 from human mononuclear cells by Bacteroides strains.

The role of anaerobic Gram-negative bacteria in inducing cytokines during mixed infections involving aerobic and anaerobic bacteria is relatively poorly defined. The purpose of this study was to establish whether or not intact Bacteroides fragilis and related species, isolated from severe infections and from the faeces of healthy persons are capable of releasing tumor necrosis factor (TNF) and IL-6 from human mononuclear cells and whole blood. The purified lipopolysaccharides of Bacteroides fragilis strain (No. 7), extracted by the aqueous phenol method from BHI cultures and from BHI culture supplemented with 5% horse serum, were also tested. TNF release was detected by the WEHI 164-dependent bioassay and IL-6 production by the B-9 cell-dependent bioassay. Heat-inactivated Bacteroides strains belonging to different species were able to induce TNF (1x10(1)-5x10(2) U/mL) and IL-6 (1x10(1)-5x10(5) pg/mL) release from human mononuclear cells. When whole blood was used, the production of TNF and IL-6 was more pronounced (very probably because of the presence of certain serum factors). The culturing conditions (the presence of 5% horse serum in the BHI broth) influenced the inducing activity of almost all strains tested. The isolated lipopolysaccharide of Bacteroides fragilis strain No. 7 proved to have a rough profile on PAGE. There were no differences in TNF and IL-6 induction when the lipopolysaccharides of the strain was cultured in BHI or in BHI supplemented with 5% horse serum. Bacteroides strains often outnumber Enterobacteriaceae in the faeces and in mixed infections, and their role in inducing and/or modulating the host response in septic shock should not be overlooked.

Journal Article↗
PubMed1993

Purification and characterization of an O2-utilizing cytochrome-c oxidase complex from Bradyrhizobium japonicum bacteroid membranes.

A cytochrome-c (cyt c) oxidase supercomplex consisting of 7-8 subunits and possessing a mass of 358-425 kDa was purified from Bradyrhizobium japonicum bacteroid membranes. At least two subunits possess c-type heme as a prosthetic group. One of the c-heme-containing components was detected in bacteroid membranes, but not in free-living cells. The complex also contains b-heme, and both b-type and c-type heme proteins were spectrophotometrically shown to form complexes with carbon monoxide. A CO difference spectrum showed an absorption minimum (trough) at 551.7 nm, possibly corresponding to a previously described cyt c-552 in bacteroid membranes. 1 mM quinacrine (Atebrin) had no effect on O2 uptake by the cytochrome-c oxidase complex, but 10 mM inhibited O2 uptake by 90%. Cytochromes b and c1 of the cytochrome bc1 respiratory complex were identified as two of the components of the bacteroid complex based upon immunoreaction with antibodies against these two proteins from B. japonicum. The oxidase complex oxidized exogenously added horse heart ferrocytochrome c concomitant with the uptake of oxygen. It could also oxidize the artificial electron donor N,N,N',N'-tetramethyl-p-phenylenediamine in the absence of added cytochrome c. Oxygen uptake activity was completely inhibited by 10 microM NaCN and 38% by 0.1 microM NaCN. The oxidase complex was not able to oxidize a ubiquinol homolog possessing a single isoprenoid unit side chain. Solubilization of bacteroid membranes in the presence of 1.0 mM EDTA resulted in complete loss of cytochrome-c oxidase activity. Leghemoglobin deoxygenation data indicated that the oxidase complex can efficiently function at free oxygen concentrations well below 1.0 microM, even though attempts to determine the oxidase's specific affinity oxygen were unsuccessful due to the formation of oxidized leghemoglobin derivatives.

Cytochrome b Group↗
PubMed1969

The relationship between nitrogen fixation and the production of HD from D2 by cell-free extracts of soya-bean nodule bacteroids.

1. Cell-free extracts prepared from soya-bean nodule bacteroids produced HD from D(2) in the presence of dithionite, an ATP-generating system and nitrogen. 2. Crude extracts of bacteroids or of Azotobacter vinelandii showed some background D(2) exchange when any one of these was omitted. 3. Partial purification of bacteroid extracts diminished this background activity and gave increased D(2) exchange and nitrogen fixation. 4. Although increasing pN(2) stimulated both reactions, the apparent K(m) (N(2)) for nitrogen fixation was much higher than the apparent K(m) (N(2)) for D(2) exchange when partially purified bacteroid extracts were used. 5. Carbon monoxide was a competitive inhibitor of nitrogen fixation by partially purified bacteroid extracts, but D(2) exchange was inhibited in a non-competitive fashion. 6. These results are discussed in relation to the possible existence of enzyme-bound intermediates of nitrogen fixation.

Adenosine Triphosphate↗
PubMed2003

Induction of interleukin-8 gene expression by black-pigmented Bacteroides in human pulp fibroblasts and osteoblasts.

AIM: To investigate the effect of black-pigmented Bacteroides on the expression of interleukin (IL)-8 gene in human pulp fibroblasts and osteoblasts. METHODOLOGY: The supernatants of Porphyromonas endodontalis, P. gingivalis and Prevotella intermedia were used to evaluate IL-8 gene expression in human pulp fibroblasts and osteoblasts. The levels of mRNAs were measured by the quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. RESULTS: Investigations of the time-dependence of IL-8 mRNA expression in black-pigmented Bacteroides-treated pulp fibroblasts and osteoblasts revealed a rapid accumulation of the transcript after 2 h of exposure, and remained elevated throughout the 24-h incubation period. In addition, IL-8 mRNA gene expression was also found in human osteoblasts stimulated with black-pigmented Bacteroides. However, black-pigmented Bacteroides was found to be more effective in the induction of IL-8 mRNA gene expression in osteoblasts than in pulp fibroblasts (P < 0.05). CONCLUSIONS: Black-pigmented Bacteroides are capable of amplifying the local immune response and promoting pulpal/periapical tissue inflammation by stimulating pulp fibroblasts and osteoblasts to express IL-8.

Analysis of Variance↗
PubMed1997

Digalactosyl diacylglycerols, plant glycolipids rarely found in bacteria, are major membrane components of bacteroid forms of Bradyrhizobium japonicum.

The membrane lipids of free living and bacteroid forms of Bradyrhizobium japonicum, obtained from nodules occupied by both typed and untyped bacteria, were isolated and characterized by a combination of NMR spectroscopy, mass spectrometry, and other chemical and physical methods. These studies indicated that both the free living and bacteroid forms of this organism contain glycolipids almost exclusively of the type found in plant cells. In the bacteroid forms, there was a dramatic shift towards the synthesis of digalactosyl diacylglycerol as the major lipid. This glycolipid has rarely been found outside of the plant kingdom and photosynthetic bacteria, and its occurrence in the bacteroid form of a plant symbiont is therefore remarkable. The presence of plant cell and organelle contaminants in the bacteroid preparations was ruled out by scanning electron microscopy, Southern blot analyses for plant DNA using specific gene probes, and chemical analyses for plant marker steroids, steroid glycosides, and cerebrosides. Digalactosyl diacylglycerol is not found in the plasma membrane of plant cells (of which the peribacteroid membrane is an extension) but is thought to be restricted to plastids. This result follows our earlier finding that the other predominant plant glycolipid, sulfoquinivosyl diacylglycerol, is a membrane component of fast growing Rhizobia and is found even when cells are cultivated in free culture where there is no question of plant contamination. The near absence of these lipids in the membranes of bacteria outside of this special group of organisms and photosynthetic bacteria suggests that the trait could have been passed on through gene transfer from plants to the bacteria at some point during the development of their symbiotic relationship. In the case of digalactosyl diacylglycerol, there is also the possibility that some common biosynthetic intermediates are used by both the plant and the bacteria. This is a striking parallel with some host-pathogen interactions.

Carbohydrate Conformation↗
PubMed2003

Induction of cyclooxygenase-2 mRNA and protein expression in human pulp cells stimulated with black-pigmented bacteroides.

Cyclooxygenase-2 (COX-2) is induced after the activation of cells by a variety of proinflammatory agents. Recently, evidence has shown that COX-2 may play a role in the pathogenesis of pulpal inflammation. However, little is known regarding the mechanism of pulpal inflammation at the site of bacterial infection. The purpose of this study was to determine the effects of the supernatants from black-pigmented Bacteroides (Porphyromonas endodontalis, Porphyromonas gingivalis, and Prevotella intermedia) on the COX-2 expression in primary human pulp cells in vitro. Investigations of the time dependence of COX-2 mRNA expression in black-pigmented Bacteroides-treated human pulp cells revealed a rapid accumulation of the transcript, a significant signal first detectable after 1 h of exposure. In addition, black-pigmented Bacteroides also up-regulated COX-2 protein expression in human pulp cells. Data from our in vitro experiment showed that black-pigmented Bacteroides were capable of stimulating COX-2 expression in human pulp cells. These results indicate that black-pigmented Bacteroides species may play an important role in the pathogenesis of pulpal inflammation. The activation of COX-2 may be one of the distinct host degradative pathways in the pathogenesis of microbial-induced pulpal/periapical inflammation.

Blotting, Western↗
PubMed1975

Ammonia assimilation by rhizobium cultures and bacteroids.

The enzymes involved in the assimilation of ammonia by free-living cultures of Rhizobium spp. are glutamine synthetase (EC. 6.o.I.2), glutamate synthase (L-glutamine:2-oxoglutarate amino transferase) and glutamate dehydrogenase (ED I.4.I.4). Under conditions of ammonia or nitrate limitation in a chemostat the assimilation of ammonia by cultures of R. leguminosarum, R. trifolii and R. japonicum proceeded via glutamine synthetase and glutamate synthase. Under glucose limitation and with an excess of inorganic nitrogen, ammonia was assimilated via glutamate dehydrogenase, neither glutamine synthetase nor glutamate synthase activities being detected in extracts. The coenzyme specificity of glutamate synthase varied according to species, being linked to NADP for the fast-growing R. leguminosarum, R. melitoti, R. phaseoli and R. trifolii but to NAD for the slow-growing R. japonicum and R. lupini. Glutamine synthetase, glutamate synthase and glutamate dehydrogenase activities were assayed in sonicated bacteroid preparations and in the nodule supernatants of Glycine max, Vicia faba, Pisum sativum, Lupinus luteus, Medicago sativa, Phaseolus coccineus and P. vulgaris nodules. All bacteroid preparations, except those from M. sativa and P. coccineus, contained glutamate synthase but substantial activities were found only in Glycine max and Lupinus luteus. The glutamine synthetase activities of bacteroids were low, although high activities were found in all the nodule supernatants. Glutamate dehydrogenase activity was present in all bacteroid samples examined. There was no evidence for the operation of the glutamine synthetase/glutamate synthase system in ammonia assimilation in root nodules, suggesting that ammonia produced by nitrogen fixation in the bacteroid is assimilated by enzymes of the plant system.

Acetylene↗
PubMed1995

Fate of Nodule-Specific Polysaccharide Produced by Bradyrhizobium japonicum Bacteroids.

A polysaccharide produced by Bradyrhizobium japonicum bacteroids in nodules (NPS) on soybean (Glycine max [L.] Merr.) roots is different in composition and structure from the extracellular polysaccharide produced in culture by this organism. Isogenic strains either capable or incapable of NPS synthesis supported similar rates of plant growth and nitrogenase activity, indicating that polysaccharide deposition was not detrimental. The possibility that NPS may have some protective or nutritional role for bacteroids was considered. Analysis of disintegrating nodules over periods of 1 to 3 months indicated greater recovery of viable bacteria from NPS+ nodules prior to the breakdown of NPS. During and after the breakdown of NPS, the decline in viable bacteria was similar for NPS+ and NPS- strains. Bacteroid destruction in senescing nodules may be accelerated by exposure to proteolytic enzymes in host cytoplasm; however, highly purified NPS had no significant effect on the in vitro activity of partially purified proteases, so protection of bacteroids via this mechanism is unlikely. B. japonicum USDA 438 did not utilize NPS as a carbon source for growth in liquid culture. In vitro assays of NPS depolymerase activity in cultured bacteria and bacteroids were negative using a variety of strains, all of which contained extracellular polysaccharide depolymerase. It seems highly unlikely that B. japonicum can utilize the polysaccharide it synthesizes in nodules, and NPS breakdown in senescing nodules is probably caused by saprophytic fungi.

Journal Article↗
PubMed1990

Occurrence of Two Pathways for Malate Oxidation in Bacteroids Isolated from Sesbania rostrata Stem Nodules during C(2)H(2) Reduction.

Malate oxidation supported C(2)H(2) reduction by bacteroids isolated from Sesbania rostrata stem nodules. Optimal activity reached 7.5 nanomoles per minute per milligram of dry weight and was in the same order of magnitude as that observed with succinate but always required a lower O(2) tension. Malate dehydrogenase (EC 1.1.1.37), purified 66-fold from bacteroids, actively oxidized malate (K(m) = 0.19 millimolar). Malic enzyme (EC 1.1.1.39) from Sesbania bacteroids had a lower affinity for malate (K(m) = 2.32 millimolar). Both enzymes exclusively required NAD(+) as cofactor and required an alkaline pH for optimal activity. 2-Oxoglutarate and oxalate, inhibiting malate dehydrogenase and malic enzyme, respectively, were used to specifically block each malate oxidation pathway in bacteroids. The predominance of malate dehydrogenase activity to support bacteroid N(2) fixation was demonstrated. The inhibition of O(2) consumption by 2-oxoglutarate confirmed the importance of the malate dehydrogenase pathway in malate oxidation. It is proposed that the utilization of malate, with regard to O(2), is important in a general strategy of this legume to maintain N(2) fixation under O(2) limited conditions.

Journal Article↗
PubMed1992

Pyrroline-5-Carboxylate Reductase in Soybean Nodules : Comparison of the Enzymes in Host Cytosol, Bradyrhizobium japonicum Bacteroids, and Cultures.

Characteristics of pyrroline-5-carboxylate reductase (P5CR) from Bradyrhizobium japonicum bacteroids and cultured rhizobia were compared with those of the enzyme in soybean nodule host cytosol. Reductase from host cytosol differed from that in bacteroids in: (a) the effect of pH on enzymic activity, (b) the capacity to catalyze both reduction of pyrroline-5-carboxylic acid and NAD(+)-dependent proline oxidation, (c) apparent affinities for pyrroline-5-carboxylic acid, and (d) sensitivities to inhibition by NADP(+) and proline. The K(1) for proline inhibition of P5CR in bacteroid cytosol was 1.8 millimolar. The properties of P5CR in B. japonicum and bacteroid cytosol were similar. The specific activities of P5CR in the cytosolic fractions of the nodule host and the bacteroid compartment were also comparable.

Journal Article↗
PubMed1978

Involvement of the cytoplasmic membrane in nitrogen fixation by Rhizobium leguminosarum bacteroids.

1. The nitrogen-fixing efficiency of freshly prepared suspensions of Rhizobium leguminosarum bacteroids from pea root nodules was considerably enhanced by addition of bovine serum albumin. Evidence was found that during preparation of bacteroids the cell membrane is exposed to the uncoupling effect of free fatty acids and to plant phospholipase D activity. Both effects could be counteracted by bovine serum albumin. 2. A technique was developed by which concentrations of free O2 and nitrogenase activity could be measured simultaneously under conditions of steady-state respiration. By means of this system it could be shown that in contrast to previous claims, high ATP/ADP ratios can be achieved in bacteroids even with a high concentration of O2 in the medium. 3. Nitrogen fixation was found to be controlled by the ATP/ADP ratio, the generation of reducing equivalents and the switch-off phenomenon. It was demonstrated that the generation of reducing equivalents for nitrogenase is regulated by the energized state and the integrity of the bacteroid cell membrane. The data indicate that the process of aerobic nitrogen fixation in R. leguminosarum bacteroids resembles that of Azotobacter vinelandii.

Adenosine Diphosphate↗
PubMed1999

Antimicrobial susceptibility of non-Bacteroides fragilis group anaerobic Gram-negative bacilli in Europe.

OBJECTIVE: To investigate the in vitro activity of a range of anti-anaerobe antimicrobials against non-Bacteroides fragilis group anaerobic Gram-negative bacilli isolated in Europe. METHODS: Isolates from 15 laboratories in 13 countries were identified by conventional methods. The MICs of 20 antibiotics were determined by an agar dilution method. RESULTS: There were 488 Prevotella spp., 174 fusobacteria, 69 Porphyromonas spp., 33 Bacteroides spp., 28 Bilophila wadsworthia and 16 Campylobacter spp. isolates, one Sutterella wadsworthensis isolate and four unidentified isolates. Penicillin resistance (and diminished susceptibility to piperacillin) was most common in Prevotella spp. and Bilophila wadsworthia but was also seen in many other species. All isolates, except three of Bilophila wadsworthia, were susceptible to amoxycillin/clavulanate. Most isolates were susceptible to cefoxitin (except Bilophila wadsworthia) and all were susceptible to the carbapenems. Clinafloxacin was the most active quinolone, followed by trovafloxacin and then sparfloxacin. Most fusobacteria were inherently resistant to the macrolides, as expected, but resistance to macrolides and a ketolide in other species was uncommon. Most Fusobacterium varium isolates were resistant to clindamycin, but resistance to clindamycin in all other species was rare. Tetracycline resistance was common but this did not affect the glycylcyclines. There was one isolate of Bacteroides putredinis resistant to chloramphenicol, and three isolates, a Bacteroides ureolyticus isolate, the Sutterella wadsworthensis isolate and one of the unnamed isolates, were metronidazole resistant. Rifampicin was active against most Prevotella and Porphyromonas spp., but not against many other genera. CONCLUSIONS: Penicillin resistance has increased in Europe among non-Bacteroides fragilis anaerobic Gram-negative bacilli, much of it due to beta-lactamase. Acquired resistance to other beta-lactams, macrolides and rifampicin has not significantly increased, and chloramphenicol and metronidazole are unaffected. However, resistance to tetracycline is common. The new compounds, a ketolide (HMR 3647), the glycylcyclines and clinafloxacin, are highly active.

Journal Article↗
PubMed1996

Enzymes of Poly-(beta)-Hydroxybutyrate Metabolism in Soybean and Chickpea Bacteroids.

The enzymatic capacity for metabolism of poly-(beta)-hydroxybutyrate (PHB) has been examined in nitrogen-fixing symbioses of soybean (Glycine max L.) plants, which may accumulate substantial amounts of PHB, and chickpea (Cicer arietinum L.) plants, which contain little or no PHB. In the free-living state, both Bradyrhizobium japonicum CB 1809 and Rhizobium sp. (Cicer) CC 1192, which form nodules on soybean and chickpea plants, respectively, produced substantial amounts of PHB. To obtain information on why chickpea bacteroids do not accumulate PHB, the specific activities of enzymes of PHB metabolism (3-ketothiolase, acetoacetyl-coenzyme A reductase, PHB depolymerase, and 3-hydroxybutyrate dehydrogenase), the tricarboxylic acid cycle (malate dehydrogenase, citrate synthase, and isocitrate dehydrogenase), and related reactions (malic enzyme, pyruvate dehydrogenase, and glutamate:2-oxoglutarate transaminase) were compared in extracts from chickpea and soybean bacteroids and the respective free-living bacteria. Significant differences were noted between soybean and chickpea bacteroids and between the bacteroid and free-living forms of Rhizobium sp. (Cicer) CC 1192, with respect to the capacity for some of these reactions. It is suggested that a greater potential for oxidizing malate to oxaloacetate in chickpea bacteroids may be a factor that favors the utilization of acetyl-coenzyme A in the tricarboxylic acid cycle over PHB synthesis.

Journal Article↗
PubMed1970

Inhibition of Shigella flexneri by the Normal Intestinal Flora III. Interactions with Bacteroides fragilis Strains in Vitro.

Five strains of Bacteroides fragilis isolated from human feces were assayed for their inhibitory activities against Shigella flexneri in vitro. Inhibition was not detected when Shigella and the Bacteroides strains were simultaneously inoculated into a defined liquid medium containing glucose. Inhibition was apparent only when Shigella was inoculated into established Bacteroides cultures. In exponential-phase cultures, the Shigella growth rate was diminished and logarithmic growth was prematurely interrupted. Shigella failed to multiply at all in stationary-phase Bacteroides cultures. An analysis of the stationary-phase cultures revealed that acetic and propionic acids were present in sufficiently high concentrations and the pH of the culture medium was sufficiently low to account for the inhibition of Shigella growth. In glucose-free Bacteroides cultures, Shigella multiplied almost as well as in control cultures, despite the presence of high concentrations of volatile fatty acids. At the high pH levels present in the glucose-free cultures, the acids were not toxic for Shigella. These results reaffirm the importance of the relationship between volatile fatty acids and pH in the inhibition of Shigella growth.

Journal Article↗
PubMed1992

The NodD protein does not bind to the promoters of inducible nodulation genes in extracts of bacteroids of Rhizobium leguminosarum biovar viciae.

In a previous study, we showed that in bacteroids, transcription of the inducible nod genes does not occur and expression of nodD is decreased by 65% (H. R. M. Schlaman, B. Horvath, E. Vijgenboom, R.J.H. Okker, and B. J. J. Lugtenberg, J. Bacteriol. 173:4277-4287, 1991). In the present study, we show, using gel retardation, that in crude extracts of bacteroids of Rhizobium leguminosarum biovar (bv.) viciae, NodD protein does not bind to the nodF, nodM, and nodO box and that it binds only weakly to the nodA box. Binding of NodD from bacteroids to nod box DNA could be restored by mild proteinase K treatment, indicating that NodD is present in bacteroids in an altered form or complex which prevents its binding to nod box DNA. In addition, a novel nodA box DNA-protein complex was found which is specific for the nodA promoter region. This novel complex was formed neither with material from cultured bacterial cells nor with an extract from uninfected roots, and it did not contain NodD but another protein. These results are consistent with the hypothesis that the protein present in the novel retardation complex acts as a transcriptional repressor causing the decreased nodD expression in bacteroids. Such a repressor also explains the lack of nodABCIJ transcription despite the weak NodD binding to the nodA box.

Bacterial Proteins↗
PubMed1994

The alternative complement pathway promotes IgM antibody-dependent and -independent adherence of Bacteroides to polymorphonuclear leukocytes through CR3 and CR1.

Natural immunoglobulin M (IgM) antibodies act synergistically with the alternative complement pathway to promote opsonization and adherence of Bacteroides thetaiotaomicron and Bacteroides fragilis to polymorphonuclear leukocytes (PMNs). This study characterizes the PMN receptors involved in adherence of Bacteroides opsonized by the alternative pathway and determines the effect of natural IgM antibodies on receptor involvement and on the molecular form of C3 deposited on the bacteria. A model system consisting of the six isolated proteins of the alternative pathway with or without supplemental isolated normal IgM was used for opsonization, and results were compared to those obtained with serum. The results demonstrate that the alternative pathway promotes adherence of Bacteroides to PMNs through complement receptors 1 and 3 (CR3), and epitopes in CR3 besides those mediating iC3b binding do not participate. The results also demonstrate that natural IgM antibodies do not influence the character of the ligands or receptors involved in this interaction.

Antibodies, Monoclonal↗
PubMed1987

Studies on bacterial synergism in mice infected with Bacteroides intermedius and Fusobacterium necrophorum.

This study was undertaken to characterize the kinetics of possible bacterial synergy using a mouse model of mixed intraabdominal infection with Bacteroides intermedius and Fusobacterium necrophorum. Female CD-1 mice were injected intraperitoneally with B. intermedius, F. necrophorum or mixtures of both organisms. Generalized septic peritonitis developed within 24 hr, with abscess formation occurring after one to two wk in survivors with the mixed infection. Involvement of the reticuloendothelial system was evidenced by dose-dependent hepatosplenomegaly, which appeared during the first wk postinfection and progressed throughout the course of the experiment. Indirect immunofluorescence confirmed the presence of both species of bacteria in frozen sections of liver tissue. The median lethal dose (LD50) was 2.11 x 10(9) for the mixture, 3.03 X 10(9) for B. intermedius alone, and 1.07 X 10(9) for F. necrophorum alone. The median abscess-producing dose (AD50), the dose required to produce abscesses in fifty percent of the surviving mice at two wk, was approx. 1/100 of the LD50 dose. The AD50 for intrahepatic abscesses was 2.8 x 10(8) for the mixture, whereas the AD50 for intraabdominal abscesses occurring in any site was 5.14 X 10(7). Both Bacteroides and Fusobacterium persisted in tissue for at least 22 wk following mixed infection. The persistence of the Bacteroides in tissue represents a synergistic result of mixed infection with Fusobacterium and contributed to the chronicity of intraabdominal abscess formation. Bacteroides, injected alone, did not produce abscesses at any of the doses tested. However, when passaged (isolated from mixed infection hepatic abscesses) B. intermedius was used, the bacteria did induce abscesses.

Abscess↗
PubMed1985

Experimentally induced subcutaneous infection by black pigmented Bacteroides species in rats.

In a rat model of anaerobic subcutaneous abscess developed to study the pathogenicity of pure cultures of black pigmented Bacteroides sp. (Bacteroides melaninogenicus and Bacteroides intermedius) maximum lesions were seen between 7 and 15 days after inoculation. Abscesses were produced by one type strain each of B. melaninogenicus and B. intermedius and by 20 of 25 clinical isolates of black pigmented Bacteroides species.

Abscess↗