Antimicrob Agents Chemother, 1999 Oct, 43(10), 2423 - 9 Molecular cloning of the gyrA and gyrB genes of Bacteroides fragilis encoding DNA gyrase; Onodera Y et al.; The genes encoding the DNA gyrase A and B subunits of Bacteroides fragilis were cloned and sequenced . The gyrA and gyrB genes code for proteins of 845 and 653 amino acids, respectively . These proteins were expressed in Escherichia coli, and the combination of GyrA and GyrB exhibited ATP-dependent supercoiling activity . To analyze the role of DNA gyrase in quinolone resistance of B . fragilis, we isolated mutant strains by stepwise selection for resistance to increasing concentrations of levofloxacin . We analyzed the resistant mutants and showed that Ser-82 of GyrA, equivalent to resistance hot spot Ser-83 of GyrA in E . coli, was in each case replaced with Phe . These results suggest that DNA gyrase is an important target for quinolones in B . fragilis. J Periodontol, 1999 Sep, 70(9), 1008 - 16 Tetracycline-coated polytetrafluoroethylene barrier membranes in the treatment of intraosseous periodontal lesions; Zarkesh N et al.; BACKGROUND: Periodontal pathogens are detrimental to periodontal healing in barrier membrane-assisted periodontal therapy . Tetracycline-coating of barrier membranes may reduce levels of infecting pathogens . This study evaluated the clinical and microbiological effects of tetracycline-coated expanded polytetrafluoroethylene (T-ePTFE) barrier membranes in the treatment of 2- to 3-wall intraosseous periodontal lesions around mandibular molars . METHODS: Eleven patients received non-coated barrier membranes (ePTFE) and 11 patients received T-ePTFE barrier membranes . Tetracycline coating was performed by placing ePTFE membranes first in a 5% tridodecylmethylammonium chloride solution and then in a basic 3% tetracycline solution . Microbiological examination included conventional culture and DNA probe analyses . Barrier membranes were removed 6 weeks after insertion . RESULTS: At baseline, the periodontal lesion depth averaged 8.0 mm in the ePTFE treated group and 7.4 mm in the T-ePTFE group . At 1 year post-treatment, the mean gain of probing attachment was 1.9 mm in the ePTFE group and 3.3 mm in the T-ePTFE group (P = 0.02) . At 3 minutes after membrane placement, suspected periodontal pathogens were detected in several ePTFE membranes but only in one T-ePTFE membrane . At 6 weeks, all membranes showed periodontal pathogens, including Porphyromonas gingivalis, Fusobacterium species, Peptostreptococcus micros, Bacteroides forsythus, and motile rods . CONCLUSIONS: This study suggests that the use of tetracycline-coated ePTFE barrier membranes can result in additional gain of clinical periodontal attachment, most likely due to the antimicrobial properties of tetracycline during initial healing. Intensive Care Med, 1999 Sep, 25(9), 1013 - 6 Multiple organ dysfunction syndrome induced by whole-body hyperthermia and polychemotherapy in a patient with disseminated leiomyosarcoma of the uterus; Pereira Arias AM et al.; OBJECTIVE: Whole-body hyperthermia (WBH) in combination with chemotherapy is a relatively new promising treatment modality for patients with cancer . The objective of this report is to present the development of an acute systemic inflammatory response syndrome (SIRS) with multiple organ dysfunction syndrome (MODS) following WBH in combination with chemotherapy . Although WBH can also induce cytokine production, MODS has not been described before in association with WBH . DESIGN: Case report . The patient was treated with WBH (core temperature 41.8 degrees C using a radiant heat device (Aquatherm) ) in combination with polychemotherapy (ifosfamide, carboplatin and etoposide (ICE) ) in the context of a clinical trial for metastatic sarcomas . SETTING: Department of medical oncology and intensive care unit of a university hospital . PATIENT: A 58-year-old Caucasian woman treated for disseminated leiomyosarcoma of the uterus, who developed SIRS with brain dysfunction, hypotension, respiratory failure and renal dysfunction following WBH/ICE . INTERVENTIONS: She was successfully treated in the intensive care unit by mechanical ventilation, inotropics and antibiotics . MEASUREMENTS AND RESULTS: There was a remarkable recovery within 2 days: she regained full conciousness, could be extubated, inotropic support was stopped and creatinine levels returned to pre-treatment levels . All cultures remained sterile . After almost complete recovery, 5 days later a second episode of fever during neutropenia occurred and, despite antibiotic treatment, she died of Bacteroides distasonis sepsis . CONCLUSION: WBH should be added as a new cause to the already known list of physical-chemical insults which can result in MODS. J Bacteriol, 1999 Oct, 181(19), 6192 - 6 Interstrain variation of the polysaccharide B biosynthesis locus of Bacteroides fragilis: characterization of the region from strain 638R; Comstock LE et al.; The sequence and analysis of the capsular polysaccharide biosynthesis locus, PS B2, of Bacteroides fragilis 638R are described, and the sequence is compared with that of the PS B1 biosynthesis locus of B . fragilis NCTC 9343 . Two genes of the region, wcgD and wcgC, are shown by complementation to encode a UDP-N-acetylglucosamine 2-epimerase and a UDP-N-acetylmannosamine dehydrogenase, respectively. Curr Microbiol, 1999 Oct, 39(4), 231 - 2 Fermentation of fenugreek fiber, psyllium husk, and wheat bran by Bacteroides ovatus V975; Al-Khaldi SF et al.; The objective of this study was to evaluate the ability of the human colonic bacterium Bacteroides ovatus V975 to ferment fenugreek fiber (Fenufibers), psyllium husk (Metamucil), and wheat bran (Wheat Chex) . Strain V975 was incubated in basal medium that contained 0.1 g of each fiber source for 0, 24, or 48 h . Little digestion of either fiber source was detected over 48 h, and little acetate or succinate was produced . From the lack of significant fiber digestion and fermentation by B . ovatus, it seems that all three fiber sources could be used as dietary supplements to increase roughage in the human diet. J Mol Evol, 1999 Oct, 49(4), 485 - 95 Gene descent, duplication, and horizontal transfer in the evolution of glutamyl- and glutaminyl-tRNA synthetases; Brown JR et al.; In translation, separate aminoacyl-tRNA synthetases attach the 20 different amino acids to their cognate tRNAs, with the exception of glutamine . Eukaryotes and some bacteria employ a specific glutaminyl-tRNA synthetase (GlnRS) which other Bacteria, the Archaea (archaebacteria), and organelles apparently lack . Instead, tRNA(Gln) is initially acylated with glutamate by glutamyl-tRNA synthetase (GluRS), then the glutamate moiety is transamidated to glutamine . Lamour et al . {(1994) Proc Natl Acad Sci USA 91:8670-8674} suggested that an early duplication of the GluRS gene in eukaryotes gave rise to the gene for GlnRS-a copy of which was subsequently transferred to proteobacteria . However, questions remain about the occurrence of GlnRS genes among the Eucarya (eukaryotes) outside of the "crown" taxa (animals, fungi, and plants), the distribution of GlnRS genes in the Bacteria, and their evolutionary relationships to genes from the Archaea . Here, we show that GlnRS occurs in the most deeply branching eukaryotes and that putative GluRS genes from the Archaea are more closely related to GlnRS and GluRS genes of the Eucarya than to those of Bacteria . There is still no evidence for the existence of GlnRS in the Archaea . We propose that the last common ancestor to contemporary cells, or cenancestor, used transamidation to synthesize Gln-tRNA(Gln) and that both the Bacteria and the Archaea retained this pathway, while eukaryotes developed a specific GlnRS gene through the duplication of an existing GluRS gene . In the Bacteria, GlnRS genes have been identified in a total of 10 species from three highly diverse taxonomic groups: Thermus/Deinococcus, Proteobacteria gamma/beta subdivision, and Bacteroides/Cytophaga/Flexibacter . Although all bacterial GlnRS form a monophyletic group, the broad phyletic distribution of this tRNA synthetase suggests that multiple gene transfers from eukaryotes to bacteria occurred shortly after the Archaea-eukaryote divergence. J Bacteriol, 1999 Sep, 181(18), 5701 - 10 Role of the alkyl hydroperoxide reductase (ahpCF) gene in oxidative stress defense of the obligate Anaerobe bacteroides fragilis; Rocha ER et al.; In this study we report the identification and role of the alkyl hydroperoxide reductase (ahp) gene in Bacteroides fragilis . The two components of ahp, ahpC, and ahpF, are organized in an operon, and the deduced amino acid sequences revealed that B . fragilis AhpCF shares approximately 60% identity to orthologues in other gram-positive and gram-negative bacteria . Northern blot hybridization analysis of total RNA showed that the ahpCF genes were transcribed as a polycistronic 2.4-kb mRNA and that ahpC also was present as a 0.6-kb monocistronic mRNA . ahpC and ahpCF mRNAs were induced approximately 60-fold following H(2)O(2) treatment or oxygen exposure of the parent strain but were constitutive in a peroxide-resistant strain . Further investigation using an ahpCF'::beta-xylosidase gene transcriptional fusion confirmed that ahpCF had lost normal regulation in the peroxide-resistant strain compared to the parent . The ahpCF mutant was more sensitive to growth inhibition and mutagenesis by organic peroxides than the parent strain, as determined by disk inhibition assays and the frequency of mutation to fusidic acid resistance . This finding suggests that the ahp genes play an important role in peroxide resistance in B . fragilis . Under anaerobic conditions, we observed increases in the number of spontaneous fusidic acid-resistant mutants of five- and sevenfold in ahpCF and ahpF strain backgrounds, respectively, and eightfold in the ahpCF katB double mutant strain compared to the parent and katB strains . In addition, ahpCF, ahpF, and ahpCF katB mutants were slightly more sensitive to oxygen exposure than the parent strain . Moreover, the isolation of a strain with enhanced aerotolerance and high-level resistance to alkyl hydroperoxides from an ahpCF katB parent suggests that the physiological responses to peroxide toxicity and to the toxic effects of molecular oxygen are overlapping and complex in this obligate anaerobe. Mayo Clin Proc, 1999 Aug, 74(8), 825 - 33 Clindamycin, metronidazole, and chloramphenicol; Kasten MJ; Clindamycin, metronidazole, and chloramphenicol are three antimicrobial agents useful in the treatment of anaerobic infections . Clindamycin is effective in the treatment of most infections involving anaerobes and gram-positive cocci, but emerging resistance has become a problem in some clinical settings . Metronidazole is effective in the treatment of infections involving gram-negative anaerobes, but it is unreliable in the treatment of gram-positive anaerobic infections and is ineffective in treating aerobic infections . Additionally, metronidazole is often the drug of choice in treating infections in which Bacteroides fragilis is a serious concern . Chloramphenicol is effective in the treatment of a wide variety of bacterial infections, including serious anaerobic infections, but is rarely used in Western countries because of concerns about toxicity, including aplastic anemia and gray baby syndrome. Antimicrob Agents Chemother, 1999 Sep, 43(9), 2320 - 2 Activities of new antimicrobial agents (trovafloxacin, moxifloxacin, sanfetrinem, and quinupristin-dalfopristin) against Bacteroides fragilis group: comparison with the activities of 14 other agents; Betriu C et al.; The antimicrobial activities of trovafloxacin, moxifloxacin, sanfetrinem, quinupristin-dalfopristin, and 14 other antimicrobial agents against 218 Bacteroides fragilis group strains were determined . A group of 10 imipenem-resistant strains were also tested . Imipenem, meropenem, and sanfetrinem had the lowest MICs of all of the beta-lactams . Quinupristin-dalfopristin inhibited all of the strains at 2 microg/ml . Overall, the MICs of trovafloxacin and moxifloxacin for 90% of the strains tested were 1 and 2 microg/ml, respectively. Antimicrob Agents Chemother, 1999 Sep, 43(9), 2251 - 5 Fluoroquinolone resistance in Bacteroides fragilis following sparfloxacin exposure; Peterson ML et al.; In vitro pharmacodynamic studies investigating the antimicrobial properties of five fluoroquinolones, (trovafloxacin, sparfloxacin, clinafloxacin, levofloxacin, and ciprofloxacin) against Bacteroides fragilis ATCC 23745 were conducted . The times required to reduce the viable counts by 3 log units were as follows: clinafloxacin, 2.9 h; levofloxacin, 4.6 h; trovafloxacin, 6 h; and sparfloxacin, 10 h . Exposure to ciprofloxacin did not achieve a 3-log decrease in viable counts . The susceptibility of B . fragilis was determined both prior to exposure and following 24 h of exposure to each of the five fluoroquinolones tested . The MICs of clinafloxacin, levofloxacin, trovafloxacin, sparfloxacin, ciprofloxacin, metronidazole, cefoxitin, chloramphenicol, and clindamycin were determined by the broth microdilution method . The MICs for B . fragilis preexposure were as follows: clinafloxacin, 0.25 microg/ml; trovafloxacin, 0.5 microg/ml; sparfloxacin, 2 microg /ml; levofloxacin, 2 microg/ml; and ciprofloxacin, 8 microg/ml . Similar pre- and postexposure MICs were obtained for cultures exposed to trovafloxacin, clinafloxacin, levofloxacin, and ciprofloxacin . However, following 24 h of exposure to sparfloxacin, a fluoroquinolone-resistant strain emerged . The MICs for this strain were as follows: clinafloxacin, 1 microg/ml; trovafloxacin, 4 microg/ml; sparfloxacin, 16 microg/ml; levofloxacin, 16 microg/ml; and ciprofloxacin, 32 microg/ml . No changes in the susceptibility of B . fragilis pre- and postexposure to sparfloxacin were noted for metronidazole (MIC, 1 microg/ml), cefoxitin (MIC, 4 microg /ml), chloramphenicol (MIC, 4 microg/ml), and clindamycin (MIC, 0.06 microg/ml) . Resistance remained stable as the organism was passaged on antibiotic-free agar for 10 consecutive days . Mutant B . fragilis strains with decreased susceptibility to clinafloxacin, trovafloxacin, sparfloxacin, levofloxacin, and ciprofloxacin were selected on brucella blood agar containing 8x the MIC of levofloxacin at a frequencies of 6.4 x 10(-9), 4x the MICs of trovafloxacin and sparfloxacin at frequencies of 2.2 x 10(-9) and 3 . 3 x 10(-10), respectively, and 2x the MIC of clinafloxacin at a frequency of 5.5 x 10(-11); no mutants were selected with ciprofloxacin . The susceptibilities of strains to trovafloxacin, levofloxacin, clinafloxacin, sparfloxacin, and ciprofloxacin before and after exposure to sparfloxacin were modestly affected by the presence of reserpine (20 microg/ml), an inhibitor of antibiotic efflux . The mechanism of fluoroquinolone resistance is being explored, but it is unlikely to be efflux due to a lack of cross-resistance to unrelated antimicrobial agents and to the fact that the MICs for strains before and after exposure to sparfloxacin are minimally affected by reserpine. Arch Immunol Ther Exp (Warsz), 1999, 47(3), 169 - 78 Adhesion molecule expression stimulated by Bacteroides thetaiotaomicron cell-surface antigens; Rokosz A et al.; Bacteroides thetaiotaomicron, a Gram-negative anaerobic rod belonging to the Bacteroides fragilis group (BFG), is involved in many systemic and local, most frequently suppurative infections in man . The cell envelope of these rods is composed of two carbohydrate-containing antigens: lipopolysaccharide (LPS) and capsular polysaccharide (CPS) . Adhesion molecules ICAM-1, VCAM-1 and E-selectin (ELAM-1) are induced on the endothelial cells by mediators of inflammation . The aim of this study was to assay the ability of B . thetaiotaomicron surface antigens to induce adhesion molecule expression on the endothelial cells . The influence of LPS and CPS on the expression of adhesion molecules on HMEC-1 cell line was examined in an ELISA test . ELISA was performed with monoclonal mouse anti-human: ICAM-1, VCAM-1 and E-selectin antibodies of the IgG class . B . thetaiotaomicron lipopolysaccharides revealed the ability to induce ICAM-1, VCAM-1 and E-selectin expression on the endothelial cells . Their activities were similar, but lower than the activity of Eschericha coli LPS . ICAM-1 was the most stimulated adhesion molecule . The strongest activation by LPS was achieved at the concentrations of 10.0 and 1.0 micrograms/ml . The ability of capsular polysaccharide to induce the expression of adhesion molecules was considerably weaker. Infect Immun, 1999 Sep, 67(9), 4945 - 9 Identification of a third metalloprotease toxin gene in extraintestinal isolates of Bacteroides fragilis; Chung GT et al.; To further understand the epidemiology of enterotoxigenic Bacteroides fragilis (ETBF), 89 extraintestinal B . fragilis strains from Seoul, Korea, were examined for secretion of B . fragilis toxin (BFT) by the HT29/C1 biologic assay and for the B . fragilis toxin gene (bft) by colony blot hybridization and PCR . Complete agreement between the three techniques was found . Overall, 34 B . fragilis strains (38%) were identified as ETBF . Eleven of the 34 ETBF strains (32%) expressed a new isoform of BFT (Korea-BFT) . This new isoform is more related to BFT-2 than to BFT-1 . Like BFT-1 and BFT-2, Korea-BFT cleaves E-cadherin, the zonula adherens protein. Infect Immun, 1999 Sep, 67(9), 4346 - 51 Detection of intrastrain antigenic variation of Bacteroides fragilis surface polysaccharides by monoclonal antibody labelling; Patrick S et al.; Bacteroides fragilis is a constituent of the normal resident microbiota of the human intestine and is the gram-negative obligately anaerobic bacterium most frequently isolated from clinical infection . Surface polysaccharides are implicated as potential virulence determinants . We present evidence of within strain immunochemical variation of surface polysaccharides in populations that are noncapsulate by light microscopy as determined by monoclonal antibody labelling . Expression of individual epitopes can be enriched from a population of an individual strain by use of immunomagnetic beads . Also, individual colonies in which either >94% or <7% of the bacteria carry an individual epitope retain this level of expression when subcultured into broth . In broth cultures where >94% of the bacteria carry a given epitope, there is no enrichment for other epitopes recognized by different polysaccharide-specific monoclonal antibodies . This intrastrain variation has important implications for the development of potential vaccines or immunodiagnostic tests. Proc Natl Acad Sci U S A, 1999 Aug 17, 96(17), 9833 - 8 A molecular sensor that allows a gut commensal to control its nutrient foundation in a competitive ecosystem; Hooper LV et al.; Little is known about how members of the indigenous microflora interact with their mammalian hosts to establish mutually beneficial relationships . We have used a gnotobiotic mouse model to show that Bacteroides thetaiotaomicron, a component of the intestinal microflora of mice and humans, uses a repressor, FucR, as a molecular sensor of L-fucose availability . FucR coordinates expression of an operon encoding enzymes in the L-fucose metabolic pathway with expression of another locus that regulates production of fucosylated glycans in intestinal enterocytes . Genetic and biochemical studies indicate that FucR does this by using fucose as an inducer at one locus and as a corepressor at the other locus . Coordinating this commensal's immediate nutritional requirements with production of a host-derived energy source is consistent with its need to enter and persist within a competitive ecosystem. Biol Pharm Bull, 1999 Jul, 22(7), 749 - 51 Metabolism of quercitrin by human intestinal bacteria and its relation to some biological activities; Kim DH et al.; When quercitrin was anaerobically incubated with human intestinal bacteria, quercetin, 3,4-dihydroxyphenylacetic acid and 4-hydroxybenzoic acid were found as metabolites . The main metabolite was quercetin . The bacterium transforming quercitrin to quercetin was Fusobacterium K-60 . However, Bacteroides JY-6, which produced alpha-L-rhamnosidase, did not transform quercitrin to quercetin . Among quercitrin and its metabolites, 3,4-dihydroxyphenylacetic acid and 4-hydroxylphenylacetic acid had more potent activity than quercitrin on in vitro anti-platelet aggregation activity, and quercetin and 3,4-dihydroxyphenylacetic acid showed more potent cytotoxicity against tumor cell lines than quercitrin and 4-hydroxylphenylacetic acid. Kaohsiung J Med Sci, 1999 Jun, 15(6), 315 - 21 {TGF-beta 1 in the experimentally induced inflammatory periodontal tissues in miniature swines}; Ko WL et al.; TGF-beta 1 is a multifunctional molecule which has unique and potent effects on many target cells and tissues . TGF-beta 1 may promote inflammatory reaction by certain intercellular interaction . TGF-beta 1 at extremely low concentrations shows strong chemotatic activity for mononuclear phagocytes and stimulates bone resorption by enhancing production of PGE2 . On the other hand, TGF-beta 1 plays a very important role in the regulation of extracellular matrix turnover presumably by modulating the action of other growth factors on matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) expression . TGF-beta 1 was identified intra- and extracellularly in the inflamed gingival tissues and the distribution was associated with areas of inflammation . Sixteen miniature swines were used in this experimental gingivitis/periodontitis study . The ligatures were placed in situ for periods of 3, 5, 8 and 13 weeks and peroral innoculations of Porphyromonas gingivalis/Actinomyces viscosus into the ligatures were carried out only in the experimental group . ELISA was used to measure the levels of TGF-beta 1 in gingival tissues from the experimental and control groups . Recording of the clinical periodontal parameters was performed and the proportion of black-pigmented Bacteroides in the ligature (plaques) removed immediately prior to the biopsies was recorded . The results revealed that the concentration of TGF-beta 1 of the experimental group was higher and significantly different in statistics on the period of third week than that of the control group . The concentration of TGF-beta 1 was significantly different between the third week and the thirteenth week in the experimental group, and was negatively related to the time-length of ligatures . Furthermore, the concentration of TGF-beta 1 was negatively related to the changes of the calculus index and gingival index . These data indicated that the concentration of TGF-beta 1 of gingival tissue exhibited dynamic changes associated with the progression of experimental periodontal inflammation . The levels of TGF-beta 1 in gingival tissue may be valuable in detecting the inflammatory reaction of periodontal tissues. FEMS Microbiol Lett, 1999 Aug 1, 177(1), 143 - 9 Design of cluster-specific 16S rDNA oligonucleotide probes to identify bacteria of the Bacteroides subgroup harbored in human feces; Miyamoto Y et al.; To develop a new simple method for identification of bacteria in the Bacteroides subgroup isolated from human feces, we designed a panel of four 16S rDNA-targeted oligonucleotide probes specific for each cluster of the Bacteroides subgroup . The probes Bac and bacvul were targeted to the Bacteroides cluster, and the probes Pre and Por have their target regions characteristic to those of the Prevotella cluster and the Porphyromonas cluster, respectively . The probes presented in this work were constructed to be specific for reference strains in each cluster of the Bacteroides subgroup and were not cross-hybridized with other major intestinal bacteria . The use of combination of these four probes will faciliate the identification of the clusters of the Bacteroides subgroup harbored in the intestine as compared to biological and biochemical testings. Biochemistry, 1999 Aug 3, 38(31), 10013 - 23 On the mechanism of the metallo-beta-lactamase from Bacteroides fragilis; Wang Z et al.; The catalytic mechanism of metallo-beta-lactamase from Bacteroides fragilis, a dinuclear Zn(II)-containing enzyme responsible for multiple antibiotic resistance, has been investigated by using nitrocefin as a substrate . Rapid-scanning and single-wavelength stopped-flow studies revealed the accumulation during turnover of an enzyme-bound intermediate with intense absorbance at 665 nm (epsilon = 30 000 M(-1) cm(-1)) . The proposed minimum kinetic mechanism for the B . fragilis metallo-beta-lactamase-catalyzed nitrocefin hydrolysis {Wang, Z., and Benkovic, S . J . (1998) J . Biol . Chem . 273, 22402-22408} was confirmed, and more accurate kinetic parameters were obtained from computer simulations and fitting . The intermediate was shown to be a novel anionic species bound to the enzyme through a Zn-acyl linkage and contains a negatively charged nitrogen leaving group . This is the first time such an intermediate was observed in the catalytic cycle of a Zn(II)-containing hydrolase and is evidence for a unique beta-lactam hydrolysis mechanism in which the amine can leave as an anion; prior protonation is not required . The electrostatic interaction between the negatively charged intermediate and the positively charged dinuclear Zn(II) center of the enzyme is important for stabilization of the intermediate . The catalytic reaction was accelerated in the presence of exogenous nucleophiles or anions, and neither the product nor the enzyme was modified during turnover, indicating that a Zn-bound hydroxide (rather than Asp-103) is the active site nucleophile . On the basis of all the information on hand, a catalytic mechanism of the B . fragilis metallo-beta-lactamase is proposed. Appl Environ Microbiol, 1999 Aug, 65(8), 3566 - 74 Microbial population changes during bioremediation of an experimental oil spill; MacNaughton SJ et al.; Three crude oil bioremediation techniques were applied in a randomized block field experiment simulating a coastal oil spill . Four treatments (no oil control, oil alone, oil plus nutrients, and oil plus nutrients plus an indigenous inoculum) were applied . In situ microbial community structures were monitored by phospholipid fatty acid (PLFA) analysis and 16S rDNA PCR-denaturing gradient gel electrophoresis (DGGE) to (i) identify the bacterial community members responsible for the decontamination of the site and (ii) define an end point for the removal of the hydrocarbon substrate . The results of PLFA analysis demonstrated a community shift in all plots from primarily eukaryotic biomass to gram-negative bacterial biomass with time . PLFA profiles from the oiled plots suggested increased gram-negative biomass and adaptation to metabolic stress compared to unoiled controls . DGGE analysis of untreated control plots revealed a simple, dynamic dominant population structure throughout the experiment . This banding pattern disappeared in all oiled plots, indicating that the structure and diversity of the dominant bacterial community changed substantially . No consistent differences were detected between nutrient-amended and indigenous inoculum-treated plots, but both differed from the oil-only plots . Prominent bands were excised for sequence analysis and indicated that oil treatment encouraged the growth of gram-negative microorganisms within the alpha-proteobacteria and Flexibacter-Cytophaga-Bacteroides phylum . alpha-Proteobacteria were never detected in unoiled controls . PLFA analysis indicated that by week 14 the microbial community structures of the oiled plots were becoming similar to those of the unoiled controls from the same time point, but DGGE analysis suggested that major differences in the bacterial communities remained. Plasmid, 1999 Jul, 42(1), 1 - 12 Genetic structure and transcriptional analysis of a mobilizable, antibiotic resistance transposon from Bacteroides; Tribble GD et al.; Tn4555 is a 12.1-kb Bacteroides antibiotic resistance transposon representative of a novel class of transmissible genetic elements that can be transferred by resident conjugative tetracycline resistance transposons (Tc(r)-elements) but are not capable of self-transfer . Previously it was shown that Tn4555 transposes by a site-specific recombination mechanism that utilizes a circular intermediate . This circular form is induced by tetracycline and it also is the substrate for conjugation . To better understand the mechanism of transposition, the entire nucleotide sequence of Tn4555 was determined and a set of genes potentially involved in transposition was identified . The transposon was 12,105 bp including a variable 6-bp coupling sequence associated with one of the transposon termini . The element had a 44.3% G + C composition and nine potential protein coding regions were observed, eight of which were encoded on the forward strand . Two putative transposition genes were found . The int gene product had significant C-terminal homology to the lambda family of integrases and the xis gene product was similar to several excisionase proteins encoded by both plasmids and conjugative transposons . The mobA mobilization gene and cfxA beta-lactamase gene of Tn4555 had been previously identified, and the remaining five open reading frames had no significant matches with sequences in the available databases . Northern hybridization analysis revealed that all Tn4555 genes except for orf-9 were expressed and two sets of genes, tnpA, int and xis, orf-5, orf-6 were organized in operons . None of the genes seemed to be induced significantly by the addition of tetracycline to cultures . Although a small 0.4-kb xis-specific transcript appeared in tetracycline-treated cultures it was not clear if this was due to an induction or if it was a specific degradation product . Microbios, 1999, 97(386), 39 - 53 Effects of a recombinant gene product and growth conditions on plasmid stability in pectinolytic Escherichia coli cells; Tierny Y et al.; The genes encoding pectin methylesterase (pme) and pectate lyase (pel) from Bacteroides thetaiotaomicron were previously cloned in Escherichia coli . In the absence of selective pressure the recombinant vectors harbouring a functional pel gene were rapidly lost . This instability was due to a toxic effect of the pel gene product when overproduced and was closely related (1) to a decrease of the growth rate, and (2) to the impossibility of transforming different strains of E . coli with the recombinant plasmids harbouring a functional pel gene . When the expression level of the pel gene was reduced and the tet gene partially deleted, the stability was greatly improved . The export of pectate lyase in the extracellular medium was significantly enhanced in the presence of glycine with a positive effect on plasmid stability for low concentrations . Furthermore, using a factorial design at two levels, the effects of tetracycline, ampicillin, glucose and magnesium on pBT4 stability were quantified. J Clin Periodontol, 1999 Jul, 26(7), 477 - 9 Inability of intact cells of Treponema denticola to degrade human serum proteins IgA, IgG and albumin; Hollmann R et al.; Treponema denticola has been shown to be associated with periodontitis in man and animals . The organism ferments amino acids and thrives on the proteins in the periodontal pocket . Accordingly, T . denticola possesses various proteolytic enzymes, including a chymotrypsin-like protease, capable of hydrolyzing a whole range of proteins, including immunoglobulins . Yet, it is not clear whether the intact cells of T . denticola can degrade immunoglobulins and albumin . The purpose of this study was to clarify this point . Three strains of T . denticola were cultured in liquid medium, and cells were harvested by centrifugation . Protein degradation in cell suspensions was assayed by capillary electrophoresis and immunonephelometry . None of the T . denticola strains appeared to be able to degrade IgA, IgG, or albumin, while a strain of P . gingivalis completely hydrolyzed these proteins . The findings suggest that, in the periodontal pocket, T . denticola depends on proteinases from other bacteria for utilization of the available serum proteins . This is in accordance with clinical data showing a close relationship between T . denticola and strongly proteolytic bacteria, such as Porphyromonas gingivalis and Bacteroides forsythus. J Clin Periodontol, 1999 Jul, 26(7), 461 - 8 Clinical and microbiological effects of initial periodontal therapy in conjunction with amoxicillin and clavulanic acid in patients with adult periodontitis . A randomised double-blind, placebo-controlled study; Winkel EG et al.; The aim of the present study was to investigate the clinical and microbiological effects of initial periodontal therapy in conjunction with systemic amoxicillin plus clavulanic acid in adult periodontitis patients using a double-blind, parallel-group, and placebo-controlled protocol . 21 patients with a clinical diagnosis of generalised adult periodontitis were recruited . Clinical measurements and microbiological assessments were carried out at baseline, 3, and 12 months post-treatment . Approximately 6 weeks after initial periodontal treatment (3-6 h), patients were randomly assigned to receive coded study medication of 500 mg amoxicillin plus 125 mg clavulanic acid (Augmentin) or placebo, every 8 h for 10 days . Patients returned for follow-up visits 3, 6, 9, and 12 months after completion of the medication . The mean plaque index (PI) at baseline was 1.1 for placebo group and 0.9 for the test group . At 3 months, the PI had dropped to 0.3 in both groups, and was maintained during the rest of the study . The changes in bleeding on probing (BOP) and gingival index (GI) in the course of the study were similar in both groups . The mean whole mouth probing pocket depth (PPD) in the placebo group was 3.8 mm at baseline and 3.9 mm in the test group . A mean reduction of 1.0 mm in the placebo group and 0.9 mm in the test group was observed during the first 3 months . No further reduction in PPD was noticed during the study period in either group . There was no statistically significant difference in the PPD reduction between the 2 groups . The change in clinical attachment level (CAL) from baseline to 3 months amounted to 0.5 mm in both groups . Between 3 and 12 months, the CAL changed in neither group . In both groups, treatment resulted in a decrease in the number of spirochetes and motile rods in positive patients, but no significant differences between either group were noted in any of the dark field microscopy observations . At baseline, 1 patient in the placebo group and 2 patients in the test group were culture positive for Actinobacillus actinomycetemcomitans (Aa) . After therapy, Aa was not detectable in the placebo group and 1 patient remained positive in the test group . In the placebo group, the number of patients positive for Porphyromonas gingivalis (Pg) decreased from 7 to 2 after therapy . In the test group, the 4 patients positive for Pg at baseline remained positive after therapy . In both groups, all subjects were positive for Prevotella intermedia (Pi) and Fusobacterium nucleatum (Fn) at baseline . At 12 months, all subjects had detectable subgingival Fn . 9 out of the 11 placebo and 8 of the 10 test patients remained positive for Pi . There were no differences in detection frequency of Peptostreptococcus micros (Pm) and Bacteroides forsythus (Bf) in both groups between baseline, 3, and 12 months post-treatment . The findings demonstrated that, in comparison to placebo, systemic amoxicillin plus clavulanic acid provided no additional clinical and microbiological effects in the treatment of adult periodontitis patients. J Periodontol, 1999 Jun, 70(6), 574 - 80 Effect of initial periodontal therapy on the frequency of detecting Bacteroides forsythus, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans; Takamatsu N et al.; BACKGROUND: Porphyromonas gingivalis, Bacteroides forsythus, and Actinobacillus actinomycetemcomitans have been described as periodontopathic bacteria, and their presence in subgingival pockets can lead to development of periodontal disease . Until now, clinical parameters have been used to evaluate the effect of conventional periodontal treatment without microbiological parameters . The present study examined the microbiological effects of initial periodontal therapy using DNA probes and the polymerase chain reaction (PCR) . METHODS: Twenty-six patients with periodontitis, 10 males and 16 females, were given instructions regarding oral hygiene, then thoroughly treated by conventional scaling and root planing . Bacterial samples were collected on paper points from 4 sites per patient at baseline and after initial therapy (total: 104 sites) . Clinical parameters including probing depth, attachment level, and bleeding on probing were also recorded for each site at baseline and after therapy . A DNA probe kit was used to monitor the frequency of B . forsythus, P . gingivalis, and A . actinomycetemcomitans, the last of which was identified by PCR . RESULTS: At baseline, B . forsythus was the bacterium most frequently detected . DNA probe analysis also showed that more than half of the sites were colonized by both B . forsythus and P . gingivalis . Initial therapy resulted in significant clinical improvement such as significant reduction in the frequency of B . forsythus and P . gingivalis detected using the DNA probe . A . actinomycetemcomitans was difficult to detect using the DNA probe, but PCR indicated that levels of A . actinomycetemcomitans did not significantly decrease . CONCLUSIONS: These results indicate that initial conventional therapy can eliminate B . forsythus and P . gingivalis, but not A . actinomycetemcomitans . When levels of these bacteria decreased to below-detectable levels, clinical improvement was significant . These results indicate that monitoring levels of these three periodontopathic bacteria may render periodontal therapy more effective and accurate. J Immunol, 1999 Jul 15, 163(2), 893 - 7 IL-2 mediates protection against abscess formation in an experimental model of sepsis; Tzianabos AO et al.; Little is known regarding the mechanism by which T cells control intraabdominal abscess formation . Treating animals with polysaccharide A (PS A) from Bacteroides fragilis shortly before or after challenge protects against abscess formation subsequent to challenge with different abscess-inducing bacteria . Although bacterial polysaccharides are considered to be T cell-independent Ags, T cells from PS A-treated animals mediate this protective activity . In the present study, we demonstrate that CD4+ T cells transfer PS A-mediated protection against abscess formation, and that a soluble mediator produced by these cells confers this activity . Cytokine mRNA analysis showed that T cells from PS A-treated animals produced transcript for IL-2, IFN-gamma, and IL-10, but not for IL-4 . The addition of IL-2-specific Ab to T cell lysates taken from PS A-treated animals abrogated the ability to transfer protection, whereas the addition of Abs specific for IFN-gamma and IL-10 did not affect protection . Finally, administration of rIL-2 to animals at the time of bacterial challenge prevented abscess formation in a dose-dependent manner . These data demonstrate that PS A-mediated protection against abscess formation is dependent upon a CD4+ T cell-dependent response, and that IL-2 is essential to this immune mechanism. J Clin Periodontol, 1999 Jun, 26(6), 374 - 80 Longitudinal study of predictive factors for periodontal disease and tooth loss; Machtei EE et al.; Longitudinal assessment of risk factors for periodontal disease is necessary to provide evidence that a putative risk factor or risk indicator is a true risk factor . The purpose of the present study was to explore longitudinally a variety of markers as possible periodontal risk factors in subjects with little or no periodontal disease at baseline . 415 subjects with mild or little periodontal disease were examined: medical and dental history; socioeconomic profile, clinical measurements, microbial samples and radiographic assessment of bone height were performed at baseline, and at a follow-up examination 2 to 5 years later . Mean probing pocket depth (PPD) at baseline was 1.99+/-0.37 mm while mean overall change was 0.1 mm which amounts to an annual rate of 0.04 mm . Overall mean clinical attachment level (1.75+/-0.6 mm) at baseline resulted in mean attachment change of 0.28 mm (0.12 mm annually) . Alveolar crestal height (ACH) at baseline (mean 2.05+/-0.85 mm) resulting in a mean net loss of 0.1 mm . Approximately 10% of all sites presented for the second visit with attachment loss exceeding the threshold (4.4% annually), while only 2.2% of all sites exhibited attachment gain (0.88% annually) . Older individuals exhibited greater mean bone loss but the least amount of attachment loss . Current smokers exhibited greater disease progression compared to non-smokers . Tooth morbidity (0.17 teeth/patient/year) was associated with greater baseline CAL and ACH loss, and an assortment of systemic conditions . Subjects who harbored Bacteroides forsythus (Bf) at baseline had greater loss in ACH; likewise, these subjects experienced greater proportions of losing sites and twice as much tooth mortality compared to Bf-negative patients . Baseline clinical parameters correlated strongly with the outcome, i.e., subjects with deeper mean pocket depth at baseline exhibited greater increase in pocket depth overtime; while subjects with greater attachment loss at baseline exhibited greater attachment loss between the 1st and 2nd visits. J Antimicrob Chemother, 1999 Jan, 43(1), 133 - 6 In-vitro susceptibilities of species of the Bacteroides fragilis group to newer beta-lactam agents; Betriu C et al.; The in-vitro activities of imipenem and four beta-lactam-beta-lactamase inhibitor combinations were tested against 816 strains of the Bacteroides fragilis group, and compared with other anti-anaerobic agents . None of the strains was resistant to metronidazole, and only one was resistant to chloramphenicol . Mezlocillin and piperacillin were moderately active, while clindamycin was the least active . Rates of resistance varied between various species . The new beta-lactam agents tested showed excellent activity; piperacillin-tazobactam and imipenem were the most active . The emergence of strains that are resistant to these agents, observed in this study, suggests there is a need to perform periodic antimicrobial susceptibility tests. J Biopharm Stat, 1999 May, 9(2), 271 - 7 Nonlinear models for in vitro kill kinetics of antibiotics; Lee ML et al.; In this study, we developed nonlinear regression models to analyze the data generated from an in vitro continuous culture system to assess the kinetics of metronidazole and trovafloxacin in inhibiting the growth of Bacteroides fragilis . The model includes parameters describing the initial shock effect of an antibiotic pulse, the overall antibiotic wash-out rate from the system, and the long-term toxicity of the antibiotic in the environment after one pulse and before the next pulse. Infect Immun, 1999 Jul, 67(7), 3525 - 32 Analysis of a capsular polysaccharide biosynthesis locus of Bacteroides fragilis; Comstock LE et al.; A major clinical manifestation of infection with Bacteroides fragilis is the formation of intra-abdominal abscesses, which are induced by the capsular polysaccharides of this organism . Transposon mutagenesis was used to locate genes involved in the synthesis of capsular polysaccharides . A 24,454-bp region was sequenced and found to contain a 15,379-bp locus (designated wcf) with 16 open reading frames (ORFs) encoding products similar to those encoded by genes of other bacterial polysaccharide biosynthesis loci . Four genes encode products that are similar to enzymes involved in nucleotide sugar biosynthesis . Seven genes encode products that are similar to sugar transferases . Two gene products are similar to O-acetyltransferases, and two products are probably involved in polysaccharide transport and polymerization . The product of one ORF, WcfH, is similar to a set of deacetylases of the NodB family . Deletion mutants demonstrated that the wcf locus is necessary for the synthesis of polysaccharide B, one of the two capsular polysaccharides of B . fragilis 9343 . The virulence of the polysaccharide B-deficient mutant was comparable to that of the wild type in terms of its ability to induce abscesses in a rat model of intra-abdominal infection. Res Microbiol, 1999 May, 150(4), 257 - 63 Bacteroides fragilis isolates compared by AP-PCR; Moraes SR et al.; Bacteroides fragilis is a component of the normal intestinal flora and an important pathogen in nonintestinal endogenous infections . It has been associated with enteric infections and has already been detected in polluted water . In order to evaluate the genetic diversity of B . fragilis, a total of 31 isolates and two reference strains were examined . This collection included strains from nonintestinal infections {12}, intestinal infections {5}, intestinal microflora {10}, aquatic environments {4}, and the reference strains ATCC 25285 and ATCC 23745 . DNA fingerprints were detected using two separate PCR reactions with different arbitrary primers . The computer-assisted system Taxotron (Institut Pasteur, Dr P . Grimont) was used to analyze the profiles obtained and dendrograms were generated . By using a distance of 0.65 as the threshold, two clusters (hereafter referred to as genotypes I and II) were defined . Strains of differents origins could be distributed into both genotypes . We were unable to detect any obvious correlation between a given genotype and the specific disease or the source of the corresponding strains. J Periodontol, 1999 May, 70(5), 478 - 84 Relationship between herpesviruses and adult periodontitis and periodontopathic bacteria; Contreras A et al.; BACKGROUND: Various mammalian viruses and specific bacteria seem to play important roles in the pathogenesis of human periodontitis . This study examined the relationship between subgingival herpesviruses and periodontal disease and potential periodontopathic bacteria in 140 adults exhibiting either periodontitis or gingivitis . METHODS: A nested-polymerase chain reaction (PCR) method determined the presence of Epstein-Barr virus type 1 and type 2 (EBV-1, EBV-2), human cytomegalovirus (HCMV), and herpes simplex virus (HSV) and a 16S rRNA PCR detection method identified Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, Prevotella intermedia, Prevotella nigrescens, and Treponema denticola . RESULTS: Using a logistic analysis, EBV-1 showed significant positive association with P . gingivalis (odds ratio {OR} 3.37), and with coinfections of P . gingivalis and P . intermedia (OR 4.03); P . gingivalis and B . forsythus (OR 3.84); P . gingivalis and T . denticola (OR 4.17); P . gingivalis, B . forsythus, and T . denticola (OR 4.06); and P . gingivalis, P . nigrescens, and T . denticola (OR 3.29) . EBV-1 also showed positive association with severe periodontitis (OR 5.09), with increasing age (OR 1.03), and with periodontal probing depth at the sample sites (OR 1.77) . HCMV was positively associated with coinfections of P . gingivalis and P . nigrescens (OR 3.23); P . gingivalis, B . forsythus, and P . nigrescens (OR 3.23); and P . gingivalis, P . nigrescens, and T . denticola (OR 2.59); with severe periodontitis (OR 4.65); and with age (OR 1.03) . Patients with mixed viral infections revealed significant associations with P . gingivalis (OR 2.27), and with coinfections of P . gingivalis and B . forsythus (OR 2.06); P . gingivalis and P . nigrescens (OR 2.91); P . gingivalis, B . forsythus, and P . nigrescens (OR 2.91); and P . gingivalis, P . nigrescens, and T . denticola (OR 2.70) with the clinical diagnosis of slight (OR 3.73), moderate (OR 3.82), or severe periodontitis (OR 4.36), and with probing depth at the sample sites (OR 1.39) . HSV and EBV-2 showed no significant associations with any of the variables tested . CONCLUSIONS: The results indicate that subgingival EBV-1, HCMV, and viral coinfections are associated with the subgingival presence of some periodontal pathogens and periodontitis . Herpesviruses may exert periodontopathic potential by decreasing the host resistance against subgingival colonization and multiplication of periodontal pathogens. Br J Biomed Sci, 1998 Sep, 55(3), 169 - 71 Biological assay for the detection of metallo-beta-lactamases in Bacteroides fragilis; Edwards R et al.; A biological assay was developed for the detection of carbapenemases, particularly metallo-beta-lactamases, in Bacteroides fragilis . The isolates tested possessed the gene (cfiA) responsible for metallo-beta-lactamase production, and showed reduced susceptibility to imipenem . Carbapenemase activity was investigated spectrophotometrically and by a biological assay in which sonicates of bacterial cells were mixed with imipenem in wells cut into Isosensitest agar inoculated with an Escherichia coli indicator organism . After incubation, zones of inhibition were measured . Reductions in zone size compared to a beta-lactamase-negative control, indicating carbapenemase production, were observed with all strains that exhibited hydrolysis of imipenem when measured spectrophotometrically, and with one isolate in which activity was not detected by spectrophotometry . Inclusion of EDTA in the well mixtures abolished the reduction in zone size, indicating the presence of metallo-beta-lactamase . This simple method can detect weak carbapenemase activity that may be overlooked by spectrophotometry. Otolaryngol Head Neck Surg, 1999 Jun, 120(6), 869 - 75 Localized sinus inflammation in a rabbit sinusitis model induced by Bacteroides fragilis is accompanied by rigorous immune responses; Jyonouchi H et al.; We evaluated inflammatory and immune responses against Bacteroides fragilis in a rabbit sinusitis model . Bacteroides was inoculated into the left maxillary sinus, and inflammatory (histology, cell number/cytology, lactose dehydrogenase, and apoptosis) and immune responses in the sinus, airway, and peripheral blood (PB) were determined for up to 4 weeks . In the inflamed sinus, the lactose dehydrogenase level was markedly elevated, with neutrophilic infiltration, severe tissue inflammation, and increased apoptosis . Low-grade tissue inflammation was present in the contralateral and sham-operated sinuses, but other parameters remained unchanged, and so did those in the airway and PB in the inoculated rabbits . Serum IgG antibody levels increased rapidly, were highest at 3 weeks, and began to decline at 4 weeks . Cellular immune responses (proliferation and interferon-gamma mRNA expression) against Bacteroides were detected in the PB of all inoculated rabbits . Vigorous immune responses against Bacteroides may have localized but failed to terminate inflammation in the sinus, indicating importance of microenvironmental factors. Adv Ther, 1998 Sep-Oct, 15(5), 277 - 87 Quinolones: clinical use and formulary considerations; Cunha BA; Quinolones are broad-spectrum antibiotics active primarily against aerobic gram-negative organisms . All quinolones have activity against oral anaerobes, but only trovafloxacin provides coverage against Bacteroides fragilis, the primary anaerobe of the abdomen/pelvis . In addition, quinolones are very active against atypical pulmonary pathogens, e.g., Legionella, but trovafloxacin is the least active against Chlamydia . As with other antibiotics, the selection of quinolones depends not simply on the degree of microbiologic activity but also on safety profile and cost . Ciprofloxacin and trovafloxacin are associated with central nervous system side effects . Photosensitivity reactions may occur with sparfloxacin . Trovafloxacin is associated with more adverse reactions than any other quinolone, and its gastrointestinal side effects are most frequent among the quinolones . Resistance potential is highest with ciprofloxacin and lowest with levofloxacin . Sparfloxacin and grepafloxacin are available only as oral formulations . Among the parenteral quinolones, ciprofloxacin and trovafloxacin are the most expensive, levofloxacin, the least expensive . Levofloxacin is preferred for general use alone or in combination because it has virtually no side effects, induces no resistance, and is the least expensive and most versatile quinolone currently available. Zentralbl Chir, 1999, 124(3), 195 - 8 {Peritoneal lavage in standardized peritonitis models}; Woltmann A et al.; The peritoneal lavage in peritonitis can be studied in a standardized manner only in animal models, because peritonitis is too variable and dependent on too many patient related factors . In this article answers are given to questions on the influence of different lavage substances on survival, local and systemic concentrations of bacteria, endotoxin, and TNF as well as on mesothelial adherence of bacteria . These data refer to results from acute models of infection published in the literature . Furthermore, we show from our own chronic peritonitis model the influence of the peritoneal lavage on abscess formation and translocation . After inoculation of a Bacteroides fragilis suspension, a chronic abscess forming peritonitis was induced . At day 3/7/14 intraabdominal abscesses were found in 2/4/6 of 8/5/6 animals in an untreated, in 1/3/5 of 5/5/5 animals in a saline lavaged, and in 5/0/2 of 5/5/5 animals in a Taurolidin lavaged group, respectively . Both, the intraabdominal and the systemic bacterial dissemination were more effectively inhibited by the Taurolidin lavage than by the saline lavage. J Clin Microbiol, 1999 Jun, 37(6), 2003 - 6 Characterization of Bacteroides forsythus strains from cat and dog bite wounds in humans and comparison with monkey and human oral strains; Hudspeth MK et al.; Bacteroides forsythus strains recovered from cat and dog bite wound infections in humans (n = 3), monkey oral strains (n = 3), and the human oral ATCC 43037 type strain were characterized by using phenotypic characteristics, enzymatic tests, whole cell fatty acid analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, PCR fingerprinting, and 16S rDNA (genes coding for rRNA) sequencing . All three bite wound isolates grew on brucella agar supplemented with 5% sheep blood, vitamin K1, and hemin . These strains, unlike the ATCC strain and previously described monkey oral and human clinical strains, did not require N-acetylmuramic acid supplementation for growth as pure cultures . However, their phenotypic characteristics, except for catalase production, were similar to those of previously identified strains . PCR fingerprinting analysis showed differences in band patterns from the ATCC strain . Also, SDS-PAGE and whole cell fatty acid analysis indicated that the dog and cat bite wound strains were similar but not identical to the human B . forsythus ATCC 43037 type strain and the monkey oral strains . The rDNA sequence analysis indicated that the three bite wound isolates had 99.93% homology with each other and 98.9 and 99.22% homology with the human ATCC 43037 and monkey oral strains, respectively . These results suggest that there are host-specific variations within each group. J Clin Microbiol, 1999 Jun, 37(6), 1824 - 8 Susceptibility testing of anaerobic bacteria: evaluation of the redesigned (Version 96) bioMérieux ATB ANA device; Dubreuil L et al.; We compared the susceptibility results for 200 clinical anaerobes with nine antibiotics obtained by using a new ATB ANA (bioMerieux) device against those obtained by the National Committee for Clinical Laboratory Standards (NCCLS) standard agar dilution method . For better evaluation of the device, we added some resistant Bacteroides fragilis group strains from our own collection: 3, 6, and 12 strains that were resistant to imipenem, ticarcillin plus clavulanic acid, and co-amoxiclav, respectively, and 2 other strains with decreased susceptibility to metronidazole . For some strains that did not grow on ATB S medium, tests were performed by using West-Wilkins medium supplemented with 1.5% agar . The new ATB ANA device made clinical categorization of the investigated strains possible, according to French (Committee of the Antibiogram of the French Society of Microbiology) or U.S . (NCCLS) breakpoints, with the following respective results: category agreement, 94.3 and 94.9%; minor errors, 4.8 and 3.8%; major errors, 0.4 and 0.8%; and very major errors 4.6 and 4.2% . The ATB ANA device was able to detect low-level metronidazole-resistant B . fragilis strains according to the French breakpoints but not the NCCLS ones . For B . fragilis and beta-lactamase-positive Prevotella strains, the clustering effect of amoxicillin MICs around the French breakpoints led to more frequent minor errors . ATB ANA is a very convenient method to determine the antibiotic susceptibilities of anaerobes . Results obtained by ATB ANA correlated well with those obtained by the reference method. APMIS, 1999 Feb, 107(2), 240 - 4 Effects of short-chain fatty acids on in vitro bacterial growth of Bacteroides fragilis and Escherichia coli; Mortensen FV et al.; Short-chain fatty acids (SCFA) are produced in the large bowel of nonruminant mammals by bacterial anaerobic fermentation . The aim of the present study was to investigate the effects of SCFA on the in vitro growth of Bacteroides fragilis and Escherichia coli . B . fragilis and E . coli isolated from fresh human clinical samples and a reference strain for each species were incubated in a meat infusion broth with increasing amounts of SCFA and grown under anaerobic conditions at a temperature of 37 degrees C . Bacterial growth was estimated by spectrophotometry . Rate of growth was calculated from the logarithmic growth phase . SCFA, in concentrations normally found in the human colon, had a significant (p<0.01) inhibitory effect of the in vitro growth rate for E . coli, while they were without effect on the in vitro growth rate of B . fragilis . It may be concluded that under in vitro conditions SCFA had growth-inhibitory effects on E . coli, while they had no effect on B . fragilis. Mol Microbiol, 1999 Apr, 32(1), 139 - 49 Characterization of the Batl (Bacteroides aerotolerance) operon in Bacteroides fragilis: isolation of a B . fragilis mutant with reduced aerotolerance and impaired growth in in vivo model systems; Tang YP et al.; YT135.2.8, a Tn4400' insertion mutant of Bacteroides fragilis strain TM4000, grows poorly when used to infect Monika or Chinese hamster ovary (CHO) cell monolayers and is outcompeted by wild-type strains in mixed infections . YT135.2.8 also shows defects in the rat granuloma pouch model system in monoculture and is completely outcompeted by the wild-type strain in a mixed infection . In addition, this mutant shows defects in a new model system consisting of CHO suspension cell columns . All of these defects may be explained by the finding that YT135.2.8 shows decreased tolerance to exposure to atmospheric oxygen (less aerotolerant) . The monolayer growth defect (MGD) of YT135.2.8 can be influenced significantly by the presence of sulphur-containing reducing agents (cysteine, dithiothreitol, thiodiglycol) or the non-sulphur reducing agent Tris-(2-carboxylethyl)phosphine (TCEP) . The defects in YT135.2.8 can be complemented by a 6.6 kb fragment of the B . fragilis chromosome . DNA sequencing of this fragment and of the regions flanking the Tn4400' insertion in the B . fragilis chromosome revealed the presence of five open reading frames, corresponding to genes bat (Bacteroides aerotolerance) A, B, C, D, E, which form the Batl operon; Tn4400' inserted within batD . All of the hypothetical proteins possess one or more membrane-spanning domains . BatA and BatB show high similarity to each other but, like BatD, they show no match to sequences of known function in the databases . BatC and BatE contain 2-4 repeated sequences similar to the tetratricopeptide repeats (TPRs) seen in many eukaryotic proteins . The function of TPR sequences in protein interactions in other systems leads to the suggestion that the Bat proteins form a complex . The Batl complex may be involved in the generation or export of reducing power equivalents to the periplasm of the B . fragilis cell. J Surg Res, 1999 May 1, 83(1), 75 - 80 Subacute sepsis impairs vascular smooth muscle contractile machinery and alters vasoconstrictor and dilator mechanisms; Price SA et al.; INTRODUCTION: Sepsis results in hyporesponsiveness to alpha-adrenergic stimulation . This is thought to be mediated by the release of vasoactive compounds from the septic endothelium or by the direct effect of sepsis on vascular smooth muscle (VSM) contractile mechanics and machinery . Previous studies have used lethal models of sepsis or endotoxemia to examine this phenomenon . The present study utilizes a clinically relevant, nonlethal model of soft tissue infection to determine the effects of sepsis on alpha-adrenergic mechanisms . We hypothesize that subacute sepsis causes impaired alpha-adrenergic vascular responsiveness by a combination of effects on adrenergic constrictor mechanisms, endogenous dilator tone, and VSM contractile function . METHODS: Male Sprague-Dawley rats underwent implantation of a 2 x 2-cm2 gauze sponge into a subcutaneous pocket created at the base of the tail . Five days after implantation, sepsis (S) was induced by inoculation of the sponge with 10(9) CFU Escherichia coli and Bacteroides fragilis . Controls (C) were inoculated with saline . Thoracic aortic harvest was performed 24 and 48 h after sponge inoculation for organ bath ring studies . Receptor-mediated (phenylephrine) and nonreceptor-mediated (KCl) maximum force of contraction (Fmax) was measured . Vessel sensitivity (pD2) to phenylephrine, acetylcholine, and KCl was calculated from dose-response curves . RESULTS: At 24 h, sepsis resulted in a lower Fmax to phenylephrine (1.15 for C vs 0.5 for S, P < 0.05 by ANOVA), despite an increase in vessel sensitivity (pD2) to alpha-adrenergic stimulation (6.70 for C vs 6.88 for S, P < 0.05 by ANOVA) . Fmax to KCl was lower in septic animals at 24 h (3 . 50 for C vs 2.77 for S, P < 0.05 by ANOVA) and sensitivity to acetylcholine (pD2) was markedly increased (6.56 for C vs 7.23 for S, P < 0.05 by ANOVA) . At 48 h, the impairment in Fmax to alpha-adrenergic stimulation (2.29 for C vs 1.72 for S, P < 0.05 by ANOVA) and KCl (3.5 for C vs 3.08 for S . P < 0.05 vs 24 h C by ANOVA) persisted without any change in sensitivity to phenylephrine or acetylcholine . CONCLUSIONS: Subacute sepsis results in an early suppression of maximum contractile force despite an increase in adrenergic receptor sensitivity (pD2) . This may be secondary to an elevation in dilator sensitivity combined with a direct effect of sepsis on VSM contractile mechanisms . Later in the septic process, however, alpha-adrenergic hyporesponsiveness ( downward arrow Fmax) is primarily due to changes in VSM contractile machinery . Protein Sci, 1999 Jan, 8(1), 249 - 52 Structural consequences of the active site substitution Cys181 ==> Ser in metallo-beta-lactamase from Bacteroides fragilis; Li Z et al.; The metallo-beta-lactamases require divalent cations such as zinc or cadmium for hydrolyzing the amide bond of beta-lactam antibiotics . The crystal structure of the Zn2+ -bound enzyme from Bacteroides fragilis contains a binuclear zinc center in the active site . A hydroxide, coordinated to both zinc atoms, is proposed as the moiety that mounts the nucleophilic attack on the carbonyl carbon atom of the beta-lactam bond of the substrate . It was previously reported that the replacement of the active site Cys181 by a serine residue severely impaired catalysis while atomic absorption measurements indicated that binding of the two zinc ions remained intact . Contradicting data emerge from recent mass spectrometry results, which show that only a single zinc ion binds to the C181S metallo-beta-lactamase . In the current study, the C181S mutant enzyme was examined at the atomic level by determining the crystal structure at 2.6 A resolution . The overall structure of the mutant enzyme is the same as that of the wild-type enzyme . At the mutation site, the side chain of Ser181 occupies the same position as that of the side chain of Cys181 in the wild-type protein . One zinc ion, Zn1, is present in the crystal structure; however, the site of the second zinc ion, Zn2 is unoccupied . A water molecule is associated with Zn1, reminiscent of the hydroxide seen in the structure of the wild-type enzyme but farther from the metal . The position of the water molecule is off the plane of the carboxylate group of Asp103; therefore, the water molecule may be less nucleophilic than a water molecule which is coplanar with the carboxylate group. Med Microbiol Immunol (Berl), 1999 Mar, 187(3), 149 - 56 Reduced bacterial dissemination and liver injury in CD14-deficient mice following a chronic abscess-forming peritonitis induced by Bacteroides fragilis; Woltmann A et al.; The CD14 myelomonocytic differentiation antigen plays a major role in acute Gram-negative infections with Escherichia coli; however, its role in chronic infections has not yet been analyzed . To address this question, we studied the role of CD14 in a chronic abscess-forming peritonitis, induced by Bacteroides fragilis . B . fragilis (3x10(8) CFU/ml) were resuspended in a liquid nutrient agar and injected into the peritoneal cavity of CD14-deficient (CD 14-/-) and normal C57BL/6J (CD 14+/+) mice, respectively . After 3 days there was a severe phlegmonous intra-abdominal inflammation in both groups . After 7 days an abscess-forming peritonitis developed and by 14 days the infectious foci were compartimentalized . These observations were indistinguishable between CD14-/- and CD14+/+ mice . Although no differences were seen in abscess formation, CD14-/- mice were able to clear B . fragilis more efficiently from the blood than CD14+/+ mice . After 3, 7, and 14 days blood cultures were B . fragilis positive in 11% (1/9), 20% (2/10), and 0% (0/9) in CD14-/-compared with 90% (9/10), 78% (7/9), and 20% (2/10) in CD14+/+ mice, respectively (P<0.05) . Furthermore, although the infection resulted in hepatocellular necrosis and severe hepatitis in both groups, at day 14 the liver cell damage was more severe in CD14+/+ than in CD14-/- mice (P<0.05) . These results show that the chronic abscess formation induced by B . fragilis capsular polysaccharides is CD14 independent; however, bacterial clearance and/or dissemination and liver cell damage are at least partially influenced by CD14-dependent mechanisms. J Virol Methods, 1999 Mar, 78(1-2), 71 - 80 Comparative study of techniques used to recover viruses from residual urban sludge; Mignotte B et al.; Eight virus extraction techniques were compared on three types of residual urban sludge for simultaneous detection of infectious enteroviruses, somatic coliphages, F-specific RNA bacteriophages and Bacteroides fragilis bacteriophages . The highest virus counts were found in extracts obtained using three extraction techniques described by respectively using a 10% beef extract solution at pH 9 and sonication, using a 0.3 M NaCl/7% beef extract solution at pH 7.5 and freon, and finally using a 0.1 M borate buffer/3% beef extract solution at pH 9 and sonication. J Clin Microbiol, 1999 May, 37(5), 1621 - 4 Simultaneous detection of Bacteroides forsythus and Prevotella intermedia by 16S rRNA gene-directed multiplex PCR; Conrads G et al.; In a 16S rRNA gene-directed multiplex PCR, Prevotella intermedia- and Bacteroides forsythus-specific reverse primers were combined with a single conserved forward primer . A 660-bp fragment and an 840-bp fragment that were specific for both species could be amplified simultaneously . A total of 152 clinical samples, subgingival plaque and swabs of three different oral mucosae, from 38 periodontitis patients were used for the evaluation. J Bacteriol, 1999 Apr, 181(8), 2564 - 71 Bacteroides fragilis transfer factor Tn5520: the smallest bacterial mobilizable transposon containing single integrase and mobilization genes that function in Escherichia coli; Vedantam G et al.; Many bacterial genera, including Bacteroides spp., harbor mobilizable transposons, a class of transfer factors that carry genes for conjugal DNA transfer and, in some cases, antibiotic resistance . Mobilizable transposons are capable of inserting into and mobilizing other, nontransferable plasmids and are implicated in the dissemination of antibiotic resistance . This paper presents the isolation and characterization of Tn5520, a new mobilizable transposon from Bacteroides fragilis LV23 . At 4,692 bp, it is the smallest mobilizable transposon reported from any bacterial genus . Tn5520 was captured from B . fragilis LV23 by using the transfer-deficient shuttle vector pGAT400DeltaBglII . The termini of Tn5520 contain a 22-bp imperfect inverted repeat, and transposition does not result in a target site repeat . Tn5520 also demonstrates insertion site sequence preferences characterized by A-T-rich nucleotide sequences . Tn5520 has been sequenced in its entirety, and two large open reading frames whose predicted protein products exhibit strong sequence similarity to recombinase-integrase enzymes and mobilization proteins, respectively, have been identified . The transfer, mobilization, and transposition properties of Tn5520 have been studied, revealing that Tn5520 mobilizes plasmids in both B . fragilis and Escherichia coli at high frequency and also transposes in E . coli. Yonsei Med J, 1998 Dec, 39(6), 578 - 86 Antimicrobial resistance patterns of Bacteroides fragilis group organisms in Korea; Lee K et al.; Antimicrobial resistance patterns of 913 clinical isolates of Bacteroides fragilis group organisms were monitored during an 8-year period in Korea . In general the resistance rates of the non-fragilis B . fragilis group species were higher than those of B . fragilis for all the drugs tested . The rate of resistance to clindamycin remarkably increased and those to some beta-lactam drugs such as piperacillin and cefotaxime also increased . No isolates were found to be resistant to imipenem, metronidazole, or chloramphenicol . beta-lactam and beta-lactamase inhibitor combinations and cefoxitin were more active than the other beta-lactams . Therefore, these agents may be considered when empirical selection of antimicrobial agents is required to treat severe anaerobic infections. Laryngoscope, 1999 Mar, 109(3), 498 - 503 Middle ear pathologic changes associated with chronic anaerobic sinusitis in rabbits; Kennedy CA et al.; OBJECTIVE/HYPOTHESIS: To study the histopathologic changes in association with the inflammatory/immune response present in the middle ears of a rabbit model of unilateral chronic anaerobic sinusitis . STUDY DESIGN: New Zealand white rabbits, two at each experimental time point . Normal rabbits and sham-operated animals served as controls . METHODS: Left maxillary sinusitis was induced by inoculating Bacteroides fragilis surgically after closure of the ostium . Cultures, lavages, and mucosa were harvested from bilateral middle ear and sinus cavities at 1, 2, 3, and 4 weeks following inoculation . Parameters analyzed include tissue for histopathologic study, immunoglobulin G antibody (IgG Ab) against B fragilis, and lactate dehydrogenase (LDH) levels in lavage samples, interferon gamma (IFN gamma) messenger RNA (mRNA) expression in mucosal tissue, and bacterial culture . RESULTS: Despite closure of the ostium of the left sinus, mild to moderate dissemination of B fragilis into the right sinus and left and right ears were observed in some but not all rabbits (2/8, 5/7, and 2/8, respectively) . Histopathologic changes in the right sinus and middle ears were much less severe in contrast to the severe inflammatory changes in the left sinus . An immune response against B fragilis appeared to occur in the sinuses and ears bilaterally independent of bacterial dissemination, as evidenced by a rise of IgG Ab in lavage fluid and detection of IFNg mRNA . Neither control nor sham-operated animals had detectable levels of IFNg mRNA or IgG Ab . In B fragilis-inoculated rabbits, the magnitude of IgG Ab responses was equivalent in the right and left ear, independent of B fragilis dissemination; IgG Ab levels in the middle ear positively correlated to each other (P < .01) and to the levels in the sinuses (P < .01 and P < .01) . LDH levels were closely associated with bacterial growth and degree of tissue inflammation . CONCLUSION: This reproducible model of chronic sinusitis provides an opportunity to study the middle ear infection and inflammatory/immune responses occurring with sinusitis . Our results indicate bilateral middle ear mucosal immune responses to an elicited sinus infection, independent of B fragilis dissemination. Pediatr Neurol, 1999 Feb, 20(2), 157 - 60 Dermoid cyst with dermal sinus tract complicated with spinal subdural abscess; Chen CY et al.; Spinal subdural abscess caused by spread of infection with the dermal sinus tract is rare in children . This article reports on a 1-year-old male with prolonged fever, progressive paraplegia, and bowel and bladder dysfunction resulting from a spinal subdural abscess secondary to an infected spinal dermoid cyst with a dermal sinus tract . This is the youngest patient to be reported having this condition . Surgical intervention was performed to find a tumor that had capsule and keratinlike contents . Culture of the abscess was positive for Escherichia coli and Bacteroides vulgatus . He received 6 weeks of parenteral antibiotic treatment . This patient illustrates the importance of urgent radiologic examination, immediate surgical resection, and appropriate antibiotic therapy for spinal subdural abscess. Gut, 1999 Apr, 44(4), 504 - 10 Bacteroides fragilis toxin 2 damages human colonic mucosa in vitro; Riegler M et al.; BACKGROUND: Strains of Bacteroides fragilis producing a 20 kDa protein toxin (B fragilis toxin (BFT) or fragilysin) are associated with diarrhoea in animals and humans . Although in vitro results indicate that BFT damages intestinal epithelial cells in culture, the effects of BFT on native human colon are not known . AIMS: To examine the electrophysiological and morphological effects of purified BFT-2 on human colonic mucosa in vitro . METHODS: For resistance (R) measurements, colonic mucosa mounted in Ussing chambers was exposed to luminal or serosal BFT-2 (1.25-10 nM) and after four hours morphological damage was measured on haematoxylin and eosin stained sections using morphometry . F actin distribution was assessed using confocal microscopy . RESULTS: Serosal BFT-2 for four hours was four-, two-, seven-, and threefold more potent than luminal BFT-2 in decreasing resistance, increasing epithelial 3H-mannitol permeability, and damaging crypt and surface colonocytes, respectively (p<0.05) . Confocal microscopy showed reduced colonocyte F actin staining intensity after exposure to BFT-2 . CONCLUSIONS: BFT-2 increases human colonic permeability and damages human colonic epithelial cells in vitro . These effects may be important in the development of diarrhoea and intestinal inflammation caused by B fragilis in vivo. Am J Obstet Gynecol, 1999 Feb, 180(2 Pt 1), 378 - 80 Elastase activity of anaerobes isolated from amniotic fluid with preterm premature rupture of membranes; Mikamo H et al.; OBJECTIVE: A total of 131 anaerobes isolated from amniotic fluid with preterm premature rupture of membranes and stored were examined for elastolytic activity by the method described by Williams et al (Lett Appl Microbiol 1988;7:173-6) . STUDY DESIGN: Each strain was spot inoculated on a Columbia blood agar plate containing 1% solubilized elastin and incubated for 5 days under anaerobic conditions . Undigested elastin was precipitated by flooding trichloroacetic acid solution onto the plate, and a clear zone was visible as the elastolytic reaction around the spot of bacterial growth . RESULTS: Ninety-three (71.0%) of 131 organisms showed a positive elastolytic reaction . Eleven of 20 strains (55.0%) of Peptostreptococcus magnus, 9 of 18 strains (50.0%) of Peptostreptococcus micros, 12 of 12 strains (100.0%) of Fusobacterium nucleatum, 15 of 28 strains (53.6%) of Bacteroides fragilis, 8 of 15 strains (53.3%) of Bacteroides thetaiotaomicron, and 38 of 38 strains (100.0%) of Prevotella bivia were elastolytic . CONCLUSION: Anaerobic bacterial species prevalent in the normal vaginal flora that were isolated from amniotic fluid of women with preterm rupture of membranes produced elastolytic activity, plausibly inducing the destruction of host constitutive components. J Clin Microbiol, 1999 Mar, 37(3), 801 - 3 Prevalence of enterotoxigenic Bacteroides fragilis in children with diarrhea in Japan; Kato N et al.; In age-matched controlled studies performed in Japan, enterotoxigenic Bacteroides fragilis was isolated from 14.9% of 114 children aged 1 to 14 years with antibiotic-unassociated diarrhea (AUD) and 6.5% of 108 children aged 1 to 6 years with antibiotic-associated diarrhea (AAD) . The difference in comparison with control children, was significant for AUD children but not AAD children. J Periodontol, 1998 Dec, 69(12), 1364 - 72 The prevalence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Bacteroides forsythus in humans 1 year after 4 randomized treatment modalities; Shiloah J et al.; The relationship between probing attachment changes in treated periodontal pockets and the prevalence of selected periodontal pathogens was assessed in 10 patients with adult periodontitis 1 year following randomized therapy . All patients had at least 1 tooth in each quadrant with an inflamed pocket of probing depth > or =5 mm and clinical attachment loss and harbored at least one of the following 3 major periodontal pathogens: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, or Bacteroides forsythus . The number of target organisms per site was determined preoperatively; at 1 week; and at 1, 3, 6, and 12 months postoperatively utilizing DNA probes . The following clinical parameters were measured and recorded preoperatively and at 1, 3, 6, and 12 months post-treatment: gingival fluid flow, gingival index, plaque index, probing depth, probing attachment level, gingival recession, and bleeding on probing . One quadrant in each patient was randomly assigned to 1 of the following 4 treatments: 1) scaling and root planing; 2) pocket reduction through osseous surgery and apically-positioned flap; 3) modified Widman flap; and 4) modified Widman flap and topical application of saturated citric acid at pH 1 for 3 minutes . All 4 treatments were rendered in one appointment using local anesthesia . No postoperative antibiotics were used, but patients rinsed with 0.12% chlorhexidine for the first 3 months postoperatively and received a prophylaxis every 3 months . This investigation revealed: 1) 30.0% of the sites were infected by at least 1 species at 3, 6, and 12 months postoperatively . 2) Failing sites were infected by a high number of both Pg and Bf These sites had a mean of 24.2+/-9.0 x 10(3) Pg and 93.1+/-42.0 X 10(3) Bf while stable sites had a mean of 6.8+/-0.5 x 10(3) Pg and 7.2+/-1.2 x 10(3) Bf (P = 0.06 and P = 0.05, respectively) . 3) The infected sites lost significantly more mean clinical attachment at 12 months (1.5+/-0.5 mm compared to a loss of 0.2+/-0.3 mm for uninfected sites, P = 0.017) . 4) The infected sites had a significantly greater BOP (67+/-14% versus 25+/-8% for uninfected sites at 12 months, P = 0.012) . 5) The choice of treatment modality did not affect the prevalence of the target species at 1 year post-treatment . These results suggest that prevalence of microbial pathogens negatively affects the 1 year outcome of periodontal surgical and nonsurgical therapy. J Med Microbiol, 1999 Jan, 48(1), 25 - 31 Characterisation of a 5.5-kb cryptic plasmid present in different isolates of Bacteroides spp . originating from Hungary; Soki J et al.; The plasmid profiles of 97 Bacteroides isolates collected during screening for different pathogenic markers of this genus were investigated . In all, 48% of 69 isolates from infections that belonged to six species harboured low mol.wt plasmids (2.8-11.0 kb) . Similar plasmids were also found in 39% of 28 isolates, belonging to eight species, from faeces of healthy persons . The two most frequently obtained types were the 5.5- and the 4.2-kb plasmids, which were present in 70% and 52% of all plasmid-bearing isolates, respectively . Restriction endonuclease analysis revealed that the 5.5-kb plasmids found in the different Bacteroides spp . exhibited the same restriction map, with the exception that pBVP61 lacked the PstI recognition site . The two plasmid types (4.2 and 5.5 kb) seem to be most widely distributed among Bacteroides isolates independent of the site of isolation and with some differences depending on geographic regions. Ann Chir Plast Esthet, 1998 Oct, 43(5), 559 - 62 {Late infection of breast implant, complication of colonic perforation . Review of the literature . Role of preventive treatment}; Petit F et al.; The authors report a cases of breast implant infection, 40 years after augmentation mammoplasty . The infection developed 6 weeks after colonoscopy complicated by acute peritonitis due to colonic perforation . Bacteroides fragilis, a usual organism of the gastrointestinal tract flora, was identified in the two septic sites (peritoneal and periprosthetic) . Contamination of the implant was haematogenous in a context of bacteraemia . Other authors have already suspected this route of contamination without any bacteriological proof . The risk of infection of breast implants is known, but the late infection rate is poorly documented . It is probably very low in view of the rare cases reported in the literature . Breast implants are not at high risk of sepsis, in contrast with prosthetic heart valves . The authors therefore do not recommend any particular preventive treatment in the case of distant infection or dental treatment . Women with breast implants must be informed and reassured: late infection of their implant is possible, but very unlikely . Recognition and prevention of this risk could be based on better long-term follow-up of breast implants. Arch Pharm Res, 1998 Oct, 21(5), 576 - 80 Degradation of acharan sulfate and heparin by Bacteroides stercoris HJ-15, a human intestinal bacterium; Kim DH et al.; When glycosaminoglycan (GAG)-degrading enzymes were measured in normal human stool suspensions, all 5 tested different stools degraded titrable heparin and acharan sulfate . GAG-degrading bacteria were screened from the isolates of human stools . Among them, HJ-15 had the most potent activities of heparinases (GAGs-degrading enzymes) . However, HJ-15 produced the enzyme even if in the media without heparin . Acharan sulfate lyase was induced by acharan sulfate and heparin . Heparinase production was also induced by these GAGs . These enzymes, acharan sulfate lyase and heparinase, were produced in exponential and stationary phase of HJ-15 growth, respectively . Optimal pHs of the acharan sulfate lyase and heparinase activities were 7.2 and 7.5, respectively . The biochemical properties of HJ-15 was similar to those of B . stercoris . However, difference from B . stercoris was utilization of raffinose . This HJ-15 also degraded chondroitin sulfates A and C. Arch Surg, 1998 Dec, 133(12), 1335 - 42 Microvascular endothelial cell control of peripheral vascular resistance during sepsis; Tucker JJ et al.; OBJECTIVE: To determine the endothelial-dependent control of decreased peripheral vascular resistance in skeletal muscle microvessels during evolving sepsis . MATERIALS AND INTERVENTIONS: Acute (4 hours, n=7), established (24 hours, n=7), or chronic (72 hours, n=8) infection was induced in Sprague-Dawley rats (150-175 g) by injecting Escherichia coli and Bacteroides fragilis (1 x 10(9) colony-forming units for both) into a subcutaneous sponge . Control animals were injected with an isotonic sodium chloride solution and analyzed at the same time points: (n=6-8 per group) . Dilation in response to the topically applied endothelial-dependent agonist acetylcholine (ACH) (1 x 10(-9) to 1 x 10(-5) mol/L) was measured in inflow first-order (A1) and precapillary fourth-order (A4) arterioles in cremaster muscle in vivo with videomicroscopy . Acetylcholine dose-response curves were used to determine vascular reactivity by calculating the concentration of ACH necessary to elicit 50% of the maximal dilator response . MAIN OUTCOME MEASURES: In vivo reactivity of striated muscle microvessels to the dilation agonist ACH during acute, established, and chronic infection . RESULTS: A1 vessels were unresponsive to all doses of ACH at all time points . A4 vessels showed an increased dilator response during short-term treatment, which deteriorated over time to depressed dilation during chronic infection . CONCLUSIONS: Precapillary A4 vessels have increased dilator reactivity during early sepsis, which progresses to depressed levels with chronic infection . A1 microvessels remain dilated and are not substantially influenced by endothelial dilator mechanisms initiated by ACH . Maximum dilation of the large A1 vessels appears to contribute to the decrease in peripheral vascular resistance noted during systemic infection. J Bacteriol, 1999 Jan, 181(1), 246 - 55 Activities of the Porphyromonas gingivalis PrtP proteinase determined by construction of prtP-deficient mutants and expression of the gene in Bacteroides species; Barkocy-Gallagher GA et al.; PrtP is a major cysteine proteinase of Porphyromonas gingivalis . The gene encoding this proteinase, prtP, was cloned into the Escherichia coli-Bacteroides shuttle vectors pFD288 and pFD340 and was expressed in Bacteroides cells, apparently under the control of its own promoter, when in pFD288, or a Bacteroides promoter present on pFD340 . Proteolytically active PrtP was detected by fibrinogen zymography in cells or spent growth medium of several Bacteroides species harboring the recombinant plasmids . The proteinase was recovered from Bacteroides fragilis ATCC 25285(pFD340-prtP) cells by 3-{(3-cholamidopropyl)-dimethyl-ammonio}-1-propanesulfonate (CHAPS) extraction and characterized with regard to exopeptidase specificity and sensitivity to proteinase inhibitors . Lys-amidolytic activity, but not Arg-amidolytic activity, was detected . PrtP was activated by cysteine and, to a lesser extent, dithiothreitol, and it was stimulated by glycine-containing compounds . It also was inhibited by Nalpha-p-tosyl-L-lysine chloromethyl ketone (TLCK) and, to a lesser extent, H-D-Tyr-L-Pro-L-arginyl chloromethyl ketone (YPRCK) and was relatively insensitive to EDTA and leupeptin . Neither B . fragilis ATCC 25285(pFD340-prtP) cells nor the CHAPS extract effected hemagglutination of sheep red blood cells or collagen cleavage, but the cells did cleave gelatin . Furthermore, P . gingivalis W12, ATCC 33277, KDP110, and HG66 with knockout mutations in prtP were constructed by allelic replacement . Unlike the parent strains, the mutant strains produced beige colonies on plates containing sheep blood . These strains also were affected in their ability to effect hemagglutination, cleave collagen, and cleave a Lys-specific peptide substrate . This report presents the results of the first characterization of the PrtP proteinase clearly in the absence of any influence by other P . gingivalis proteins and describes the properties of P . gingivalis cells defective in the production of PrtP. J Clin Periodontol, 1998 Nov, 25(11 Pt 1), 857 - 64 Additional clinical and microbiological effects of amoxicillin and metronidazole after initial periodontal therapy; Winkel EG et al.; The aims of this study were to evaluate the clinical and microbiological effects of initial periodontal therapy (IT) and to determine the additional effects of systemic amoxicillin (Flemoxin Solutab) 375 mg TID plus metronidazole 250 mg TID therapy, in patients with adult Actinobacillus actinomycetemcomitans (Aa)-associated periodontitis in conjunction with either Porphyromonas gingivalis (Pg), Bacteroides forsythus (Bf) and/or Prevotella intermedia (Pi) . In addition the adverse effects of the antimicrobial therapy were also documented . A total of 22 patients were enrolled . The deepest, bleeding pocket in each quadrant was selected and at these 4 experimental sites clinical measurements and microbiological testing was carried out at baseline, after (IT), i.e., 21 weeks after baseline, and after antimicrobial therapy (AM), i.e., 35 weeks after baseline . At baseline, the mean plaque index (PI) amounted 0.5, 0.1 after IT and 0.3 after systemic AM . The mean bleeding index decreased from 1.6 to 1.2 after IT and a further decrease to 0.7 after AM was noted . Suppuration was completely eliminated after AM . The mean change of probing pocket depth (PPD) after IT amounted 1.4 mm and was further reduced with an additional mean change of 1.1 mm after medication . Clinical attachment gain was 1.1 mm after IT and an additional 0.9 mm was observed after AM . One of the 22 Aa positive patients and 4 of 17 Pg positive patients became negative for these species after IT . The number of patients with detectable Pi decreased from 16 to 10 after IT . After AM, in comparison to baseline, suppression below detection level for Aa was achieved in 19 out of 22, for Pg in 9 out of 17, for Bf in 13 out of 14, and for Pi in 11 out of 16 patients . By contrast, higher frequencies of Peptostreptococcus micros and Fusobacterium nucleatum were found after AM . On the basis of the microbiological results the study group was separated into 2 subgroups: group A consisted of subjects who had no detectable levels of Aa, Pg, Bf and <5% of Pi after AM . Group B consisted of those who still showed presence of one of these 3 species and/or > or =5% levels of Pi . After AM, group B had significantly higher PI, BI, PPD and CAL scores then group A . It is concluded that group A showed low plaque scores and no detectable periodontal pathogens . This microbiological condition has been associated with a long-term stable periodontium. Proc Natl Acad Sci U S A, 1998 Dec 8, 95(25), 14979 - 84 Bacteroides fragilis enterotoxin cleaves the zonula adherens protein, E-cadherin; Wu S et al.; Strains of Bacteroides fragilis associated with diarrheal disease (enterotoxigenic B . fragilis) produce a 20-kDa zinc-dependent metalloprotease toxin (B . fragilis enterotoxin; BFT) that reversibly stimulates chloride secretion and alters tight junctional function in polarized intestinal epithelial cells . BFT alters cellular morphology and physiology most potently and rapidly when placed on the basolateral membrane of epithelial cells, suggesting that the cellular substrate for BFT may be present on this membrane . Herein, we demonstrate that BFT specifically cleaves within 1 min the extracellular domain of the zonula adherens protein, E-cadherin . Cleavage of E-cadherin by BFT is ATP-independent and essential to the morphologic and physiologic activity of BFT . However, the morphologic changes occurring in response to BFT are dependent on target-cell ATP . E-cadherin is shown here to be a cellular substrate for a bacterial toxin and represents the identification of a mechanism of action, cell-surface proteolytic activity, for a bacterial toxin. Curr Microbiol, 1999 Jan, 38(1), 22 - 6 The translational hop junction and the 5' transcriptional start site for the Prevotella loescheii adhesin encoded by plaA; Manch-Citron JN et al.; The Prevotella loescheii adhesin gene, plaA, contains a coding gap between a small open reading frame (ORF-1) and a large open reading frame (ORF-2) . Translation of the plaA mRNA requires bypassing this 29-nt coding gap on the plaA transcript . We have determined the N-terminal peptide sequence of the SO34 adhesin beyond the gap sequence . This sequence shows that the peptide junction between ORF-1 and ORF-2 is continuous in the adhesin and supports the conclusion that synthesis of the SO34 adhesin occurs by a ribosomal hop mechanism . To elucidate upstream signals, we used the 5' RACE (rapid amplification of cDNA ends) technique to map the start point of the plaA mRNA . DNA sequencing of plasmids with the 5' RACE products placed the 5' end of plaA mRNA 270 nt upstream from the plaA start codon . A region corresponding to a Bacteroides fragilis promoter consensus sequence precedes this start site. Protein Sci, 1998 Nov, 7(11), 2476 - 9 The identification of metal-binding ligand residues in metalloproteins using nuclear magnetic resonance spectroscopy; Scrofani SD et al.; The identification of metal-binding ligands in metalloproteins is an important step in gaining detailed information regarding the environment of the active site . Traditionally, techniques such as 13Cd-substitution for the active metal followed by isotope-filtered NMR techniques have been used to this end . However, for medium to high molecular weight proteins (>20 kDa), these experiments may not be beneficial due to extensive 1H spectral overlap . Here, we describe an alternative approach, where metal-binding ligands such as histidine and cysteine are specifically 15N backbone labeled, excess EDTA is added and changes to (1H-15N) HSQC spectra are followed . Under these conditions, the amide groups of all 15N labeled histidine and cysteine residues, which were either ligands or residues close to the active site, were identified unambiguously for metallo-beta-lactamase from Bacteroides fragilis. Infect Immun, 1998 Dec, 66(12), 5703 - 10 Cloning, expression, and sequencing of a cell surface antigen containing a leucine-rich repeat motif from Bacteroides forsythus ATCC 43037; Sharma A et al.; Bacteroides forsythus is a recently recognized human periodontopathogen associated with advanced, as well as recurrent, periodontitis . However, very little is known about the mechanism of pathogenesis of this organism . The present study was undertaken to identify the surface molecules of this bacterium that may play roles in its adherence to oral tissues or triggering of a host immune response(s) . The gene (bspA) encoding a cell surface-associated protein of B . forsythus with an apparent molecular mass of 98 kDa was isolated by immunoscreening of a B . forsythus gene library constructed in a lambda ZAP II vector . The encoded 98-kDa protein (BspA) contains 14 complete repeats of 23 amino acid residues that show partial homology to leucine-rich repeat motifs . A recombinant protein containing the repeat region was expressed in Escherichia coli, purified, and utilized for antibody production, as well as in vitro binding studies . The purified recombinant protein bound strongly to fibronectin and fibrinogen in a dose-dependent manner and further inhibited the binding of B . forsythus cells to these extracellular matrix (ECM) components . In addition, adult patients with B . forsythus-associated periodontitis expressed specific antibodies against the BspA protein . We report here the cloning and expression of an immunogenic cell surface-associated protein (BspA) of B . forsythus and speculate that it mediates the binding of bacteria to ECM components and clotting factors (fibronectin and fibrinogen, respectively), which may be important in the colonization of the oral cavity by this bacterium and is also a target for the host immune response. Gut, 1998 Nov, 43(5), 651 - 5 Heterogeneity in responses by primary adult human colonic epithelial cells to purified enterotoxin of Bacteroides fragilis; Sanfilippo L et al.; BACKGROUND: Enterotoxigenic strains of Bacteroides fragilis (ETBF) have been implicated in diarrhoeal illness in livestock and children, but their role in adult human colonic disease is unknown . AIMS: To investigate responses by primary adult human colonic epithelial cells to purified B fragilis toxin (BFT) . METHODS: BFT was purified from culture supernatant of a highly toxigenic strain of ETBF . Morphological changes to primary colonic epithelial cells, in response to purified BFT, were studied in organ culture of colonic biopsy specimens from 15 adults . RESULTS: BFT induced epithelial cell cytotoxicity in colonic biopsy specimens from 12/15 subjects . The BFT induced morphological changes were characterised by epithelial cell rounding, separation from adjacent cells, and detachment from the basement membrane . In severely affected specimens, almost all the epithelial cells were affected . There was heterogeneity between subjects in the rate at which BFT induced epithelial cell cytotoxicity occurred . Furthermore, in colonic biopsy specimens from three subjects, exposure to BFT did not induce any significant morphological changes to epithelial cells . CONCLUSION: BFT is capable of inducing cytotoxicity in primary adult human colonic epithelial cells . Such an effect of ETBF derived BFT on epithelial cells in the colon in vivo would be expected to lead to mucosal inflammation and diarrhoea . Heterogeneity in responses by primary colonocytes probably reflects the outcome of host-BFT interactions . Such interactions in vivo could determine the occurrence of colonic disease in some individuals but not others. FEBS Lett, 1998 Oct 30, 438(1-2), 137 - 40 Mono- and binuclear Zn-beta-lactamase from Bacteroides fragilis: catalytic and structural roles of the zinc ions; Paul-Soto R et al.; The Bacteroides fragilis Zn-beta-lactamase is active with a mono- and a binuclear zinc site . The apoenzyme produced by removal of both Zn ions does not recover full activity upon readdition of Zn2+ in contrast to an active mono-Zn form prepared at pH 6.0 . Differences in k(cat) values observed are substrate-dependent implying distinct mechanisms for the mono- and binuclear species . The substrate profile of a Zn,Cd hybrid obtained by selective exchange of one zinc ion is different from that of the Zn2 enzyme with a remarkable 15-fold increased activity with cefoxitin as substrate. Berl Munch Tierarztl Wochenschr, 1998 Oct, 111(10), 379 - 86 {Investigations into the occurrence and the antibiotic susceptibility of gram negative anaerobes of the genera Bacteroides, Prevotella, Porphyromonas and Fusobacterium in specimens obtained from diseased animals}; Even H et al.; From different samples of 247 diseased animals (cattle, sheep, goat, horse, pig, dog, cat, rodent, zoo-animals), 410 strains of gram-negative anaerobes were cultured . 297 isolates (72.4%) could be differentiated to the species level by using cultural-biochemical methods, gaschromatography and cell-wall-lipidanalysis . They belonged to 29 different species . For an additional 113 strains (27.6%) only the genus could be determined . Bacteria belonging to the genus Fusobacterium occurred with the highest isolation rates (36% of all strains) in the samples examined, followed by Bacteroides spp . (26.1%), Prevotella spp . (19.9%) and Prophyromonas spp . (17.8%) . Fusobacterium necrophorum was the single species isolated most frequently . Antibiotic susceptibility tests by E-test were performed on 100 strains belonging to the the above mentioned genera . Of these strains 18% were resistant to penicillin and 20% to tetracycline . The resistant strains belonged mainly to the Bacteroides fragilis-group . Resistant rates to most other antimicrobial agents tested were Amoxicillin in combination with clavulanic acid: 1%, Chloramphenicol: 3%, Clindamycin:8% . All 100 selected strains proved to be susceptible to Metronidazol. J Bacteriol, 1998 Nov, 180(22), 5906 - 12 Characterization of a peroxide-resistant mutant of the anaerobic Bacterium bacteroides fragilis; Rocha ER et al.; A Bacteroides fragilis mutant resistant to hydrogen peroxide and alkyl peroxide was isolated by enrichment in increasing concentrations of hydrogen peroxide . The mutant strain was constitutively resistant to 100 mM H2O2 and 5 mM cumene hydroperoxide (15-min exposure) . In contrast, the parent strain was protected against <10 mM H2O2 when the peroxide response was induced with a sublethal concentration of H2O2, and no protection was observed in untreated cells . In addition, catalase activity in the mutant strain was not repressed in anaerobic cultures as reported previously for the parent strain . Comparison of the protein profile of crude extracts of the B . fragilis strains revealed that at least three oxidative stress-induced proteins in the parent strain were constitutively expressed in the mutant as detected by nondenaturing polyacrylamide gel electrophoresis . N-terminal amino acid sequence of these overexpressed proteins confirmed the presence of a deregulated catalase (KatB), an alkyl hydroperoxidase reductase subunit C (AhpC), and a Dps/PexB homologue . Northern blot analysis and katB::cat transcriptional fusion studies revealed that in the mutant, katB was deregulated compared to the parent and that katB was controlled by a trans-acting regulatory mechanism . Moreover, constitutive expression of KatB and of the AhpC and Dps homologues in the H2O2-resistant mutant suggests that these proteins may share a common oxidative stress transcriptional regulator and may be involved in B . fragilis peroxide resistance. J Periodontol, 1998 Oct, 69(10), 1111 - 8 Risk indicators for harboring periodontal pathogens; Umeda M et al.; The risk for harboring 6 putative periodontal pathogens in 4 selected periodontal pockets, in whole saliva, or in either site (i.e., orally) was determined in 52 Caucasians, 49 African-Americans, 48 Asian-Americans, and 50 Hispanics living in Los Angeles . 16S rRNA PCR analysis assessed the presence of Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, and Treponema denticola . Step-wise regression analysis determined the relationship between the occurrence of each organism and various explanatory variables (risk indicators) . Periodontal probing depth or disease severity was positively associated with all 6 study organisms . African-Americans carried an increased risk for harboring P . gingivalis in saliva (odds ratio {OR} 2.95) and orally (OR 2.66), and a reduced risk for harboring T . denticola orally (OR 0.34) . Asian-Americans showed an increased risk for harboring A . actinomycetemcomitans in periodontal pockets (OR 6.63) and P . gingivalis in periodontal pockets (OR 5.39), in saliva (OR 5.74), and orally (OR 5.81) . Hispanics demonstrated an increased risk for harboring A . actinomycetemcomitans in periodontal pockets (OR 12.27) and P . gingivalis in periodontal pockets (OR 6.07), in saliva (OR 8.72), and orally (OR 7.98) . Age was positively associated with the prevalence of P . gingivalis in saliva (OR 1.20) and orally (OR 1.20), and of A . actinomycetemcomitans orally (OR 1.18) . The male gender was a risk factor for harboring P . intermedia in periodontal pockets (OR 2.40), in saliva (OR 3.31), and orally (OR 4.25), and for harboring P . nigrescens in saliva (OR 2.85) . The longer the subjects resided in the United States, the less likely A . actinomycetemcomitans was detected orally (OR 0.82) . Former smokers demonstrated a decreased risk for harboring A . actinomycetemcomitans in saliva (OR 0.23) . Current smokers displayed an increased risk for harboring T . denticola in periodontal pockets (OR 4.61) . The number of dental visits in the past 10 years was inversely related to the prevalence of P . intermedia orally (OR 0.96) . The prevalence of P . intermedia in saliva was positively associated with the length of time from the last dental visit (OR 1.01) . This study suggests that genetic and/or environmental factors predispose subjects to oral colonization by putative periodontal pathogens. Appl Environ Microbiol, 1998 Nov, 64(11), 4384 - 9 Molecular characterization of epiphytic bacterial communities on charophycean green algae Fisher MM, Wilcox LW, Graham LE. Epiphytic bacterial communities within the sheath material of three filamentous green algae, Desmidium grevillii, Hyalotheca dissiliens, and Spondylosium pulchrum (class Charophyceae, order Zygnematales), collected from a Sphagnum bog were characterized by PCR amplification, cloning, and sequencing of 16S ribosomal DNA . A total of 20 partial sequences and nine different sequence types were obtained, and one sequence type was recovered from the bacterial communities on all three algae . By phylogenetic analysis, the cloned sequences were placed into several major lineages of the Bacteria domain: the Flexibacter/Cytophaga/Bacteroides phylum and the alpha, beta, and gamma subdivisions of the phylum Proteobacteria . Analysis at the subphylum level revealed that the majority of our sequences were not closely affiliated with those of known, cultured taxa, although the estimated evolutionary distances between our sequences and their nearest neighbors were always less than 0.1 (i.e., greater than 90% similar) . This result suggests that the majority of sequences obtained in this study represent as yet phenotypically undescribed bacterial species and that the range of bacterial-algal interactions that occur in nature has not yet been fully described. Appl Environ Microbiol, 1998 Nov, 64(11), 4307 - 12 Detection of infectious enteroviruses, enterovirus genomes, somatic coliphages, and Bacteroides fragilis phages in treated wastewater; Gantzer C et al.; In this study, three types of treated wastewater were tested for infectious enteroviruses, the enterovirus genome, somatic coliphages, and Bacteroides fragilis phages . The aim of this work was to determine whether the presence of the two types of bacteriophages or of the enterovirus genome was a good indicator of infectious enterovirus contamination . The enterovirus genome was detected by reverse transcription-polymerase chain reaction . Infectious enteroviruses were quantified by cell culturing (BGM cells), and the bacteriophages were quantified by plaque formation on the host bacterium (Escherichia coli or B . fragilis) in agar medium . Forty-eight samples of treated wastewater were analyzed . Sixteen samples had been subjected to a secondary treatment for 8 to 12 h (A), 16 had been subjected to a secondary treatment for 30 h (B1), and 16 had been subjected to both secondary and tertiary treatments (B2) . The mean concentrations of somatic coliphages were 4.9 x 10(4) PFU . liter-1 for treatment line A, 9.8 x 10(3) PFU . liter-1 for B1, and 1.4 x 10(3) PFU . liter-1 for B2, with all the samples testing positive (100%) . The mean concentrations of B . fragilis phages were 1.7 x 10(3) PFU . liter-1 for A (100% positive samples), 17 to 24 PFU . liter-1 for B1 (44% positive samples), and 0.8 to 13 PFU . liter-1 for B2 (6% positive samples) . The mean concentrations of infectious enteroviruses were 4 most probable number of cytopathogenic units (MPNCU) . liter-1 for A (31% positive samples) and <1 MPNCU . liter-1 for B1 and B2 (0% positive samples) . The percentages of samples testing positive for the enterovirus genome were 100% for A, 56% for B1, and 19% for B2 . The percentages of samples testing positive for the enterovirus genome were significantly higher than those for infectious enteroviruses . This finding may have been due to the presence of noninfectious enteroviruses or to the presence of infectious enteroviruses that do not multiply in BGM cell cultures . However, under our experimental conditions, nondetection of the genome implies the absence of infectious viruses . There was a significant correlation between the concentration of somatic coliphages or B . fragilis phages and the presence of infectious enteroviruses or the presence of the enterovirus genome . However, the somatic coliphage concentration did not lead to fluctuations in the infectious enterovirus concentration, whereas the B . fragilis phage concentration did. J Endod, 1992 Sep, 18(9), 431 - 4 Porphyromonas (Bacteroides) endodontalis: its role in endodontal infections; van Winkelhoff AJ et al.; Porphyromonas endodontalis (formerly Bacteroides endodontalis) is a black-pigmented anaerobic Gram-negative rod which is associated with endodontal infections . It has been isolated from infected dental root canals and submucous abscesses of endodontal origin . The presence of P . endodontalis in infected dental root canals has been correlated with symptoms of an acute infection . It is occasionally found on oral mucous membranes and periodontal pockets . P . endodontalis has shown relatively low virulence in experimental monoinfections . In anaerobic mixed infections it can play an essential role . Differences in virulence between strains have been related to capsular material . On the basis of different types of capsules, three serotypes have been described . P . endodontalis is sensitive to a wide range of antibiotics, including the penicillins, the tetracyclines, and metronidazole. J Clin Immunol, 1998 Sep, 18(5), 355 - 67 Antigenic variation and cross-reactivity in Bacteroides forsythus clinical isolates detected by western blot; Sims TJ et al.; Bacteroides forsythus is one of the etiologic agents of destructive periodontal diseases . Determining which antigenic components of the bacterium are recognized in the immune response of periodontitis patients is an important step in assessing strategies for vaccine development . The aim of this study was to identify the major strain-variable and cross-reactive antigens of B . forsythus clinical isolates recognized by serum IgG from patients with early-onset rapidly progressive periodontitis . Ten patient sera with measurable IgG against antigenic components of the species were identified by Western blot . Positive sera were tested by checkerboard ELISA to identify those most responsive to strain-variable antigens in nine clinical isolates and ATCC strain 43037 . Correlation analysis of the ELISA data suggested that different subsets of isolates were preferentially recognized by different sera . Western blots revealed that certain sera also recognized major shared components across all the isolates, but preferential recognition of different isolate subsets by different patients was clearly confirmed . To determine if the variable antigens recognized were nonprotein, proteinase K-digested isolates were compared to undigested controls by Western blot . The main strain-variable antigens were proteinase resistant, while proteins at 200 and 210 kDa were identified as the major shared components . Two-dimensional SDS-PAGE revealed that these proteins are the quantitatively dominant heat-modifiable components of the cell envelope . Even though variable antigens are prominent in the immune response of patients, a cross-protective vaccine based on the shared envelope proteins of B . forsythus seems feasible in light of these observations. Infect Immun, 1998 Nov, 66(11), 5224 - 31 Resident enteric bacteria are necessary for development of spontaneous colitis and immune system activation in interleukin-10-deficient mice; Sellon RK et al.; Mice with targeted deletion of the gene for interleukin-10 (IL-10) spontaneously develop enterocolitis when maintained in conventional conditions but develop only colitis when kept in specific-pathogen-free (SPF) environments . This study tested the hypothesis that enteric bacteria are necessary for the development of spontaneous colitis and immune system act