PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “FUSOBACTERIUM”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed1998

Phospholipids of Fusobacterium spp.

The aim of this study was to analyse individual polar lipid analogues, within each lipid family present, of fusobacteria using fast atom bombardment mass spectrometry (FAB-MS). Polar lipid extracts were prepared, washed and dried. Samples, dispersed in a matrix of m-nitrobenzyl alcohol, were analysed by negative ion FAB-MS using xenon as the reagent gas. Major anion peaks observed in the low mass region of mass/charge (m/z), 211, 221, 225, 227, 239, 241, 249, 251, 253, 255, 273, 277, 279, 281, 289 and 291, were consistent with the presence of C13:1, C14:3, C14:1, C14:0, C15:1, C15:0, C16:3, C16:2, C16:1, C16:0, unknown, C18:3, C18:2, C18:1, unknown and C19:3 carboxylate anions. In the high mass region, major anion peaks observed with m/z 644, 646, 648, 660, 662, 672, 673, 674, 686, 688, 689, 690, 698, 700, 701, 703, 714, 716, 717 and 719 were consistent with the presence of phosphatidylethanolamine (PE) (29:2), PE (29:1), PE (29:0), PE (30:1), PE (30:0), PE (31:2), first isotope of PE (31:2), PE (31:1), PE (32:2), PE (32:1), first isotope peak of PE (32:1), PE (30:0), PE (33:3), PE (33:2), phosphatidylglycerol (PG) (31:3), PG (31:2), PE (34:2), PE (34:1), PG (32:2) and PG (32:1). We conclude that FAB-MS can provide data on individual analogues of PE and PG from Fusobacterium spp. not readily obtained by other means. Furthermore, the phospholipid profile is diagnostic for the genus.

Fusobacterium↗
PubMed1999

Identification of positively charged residues of FomA porin of Fusobacterium nucleatum which are important for pore function.

FomA porin is the major outer-membrane protein of Fusobacterium nucleatum. It exhibits the functional properties of a general diffusion porin, but has no sequence similarity to other porins. According to the proposed topology model, each monomer of this trimeric protein is a beta-barrel consisting of 16 transmembrane segments with eight surface-exposed loops. Several conserved charged residues are proposed to extend from the beta-barrel wall into the aqueous channel lumen, and may contribute to a transverse electric field similar to that at the pore constriction of porins with known structure. The goal of our study was to identify particular basic residues contributing to such an electric field in FomA. Several arginines and lysines were replaced by negatively charged glutamates or uncharged alanines. The mutated FomA porins were expressed in Escherichia coli, and the effects on pore function were studied in vivo, by assaying the uptake rate of beta-lactam antibiotics, and in vitro after reconstitution of the purified proteins in lipid bilayer membranes. Some of the point mutations had a significant impact on the channel properties. The substitution R92A produced a 130% increased permeability of the zwitterionic beta-lactam cephaloridine, and the cation selectivity of R92E increased by 70%. The effects of the R90E substitution on channel properties were similar. Most of the point mutations had a minor effect on the voltage gating of the FomA channel, resulting in an increased sensitivity, except for K78E, which showed a decreased sensitivity. The latter mutation had no effect on cation selectivity, but the K78A substitution improved the uptake rate of cephaloridine. The results presented here indicate that arginines 90 and 92 are probably part of the constriction zone of the FomA porin, and lysine 78 and arginines 115 and 117 are probably in close proximity to this region as well.

Amino Acid Sequence↗
PubMed1997

Conversion of DL-threonine, D-threonine and 2-oxobutyrate into propionate and 2-hydroxybutyrate by Fusobacterium species.

The present investigation examined DL-threonine, D-threonine and 2-oxobutyrate conversion into propionate and 2-hydroxybutyrate by various type strains and clinical isolates of Fusobacterium. Except for Fus. naviforme, the type strains were able to produce varying degrees of propionate and/or 2-hydroxybutyrate from DL-threonine. Additionally, D-threonine was converted into an equimolar amount of propionate by Fus. necrophorum subsp. necrophorum, Fus. nucleatum subsp. nucleatum and Fus. varium, and to a lower but significant amount by Fus. mortiferum and Fus. perfoetens. However, the level of propionate remained unchanged for Fus. nucleatum subsp. fusiforme, Fus. nucleatum subsp. vincentii, Fus. naviforme, Fus. necrophorum subsp. funduliforme, Fus. gonidiaforme and Fus. russii. 2-Oxobutyrate was fermented to propionate by all type strains, although Fus. russii reduced it mainly to 2-hydroxybutyrate. Thus, an attempt was made to make use of these features in order to identify clinical isolates.

Fusobacterium↗
PubMed2001

Evaluation of co-aggregation among Streptococcus mitis, Fusobacterium nucleatum and Porphyromonas gingivalis.

AIMS: To develop a semi-quantitative method for evaluating co-aggregation reactions among three bacterial species, and to examine the influence of Fusobacterium nucleatum on the adherence of Porphyromonas gingivalis. METHODS AND RESULTS: The method involves coating hydroxyapatite (HAP) discs with streptococcal cells and treatment with radio-labelled bacterial cell suspensions. The sensitivity of the method was estimated by comparison with a turbidometric co-aggregation assay. Results from the two methods were in close agreement. Streptococcus mitis-coated HAP discs were immersed in a 3H-labelled Fus. nucleatum cell suspension and then a 14C-labelled P. gingivalis cell suspension. The discs were then pyrolysed to recover and quantify the released 3H and 14C radioactivity. The number of Fus. nucleatum cells on the discs increased with immersion time and this, in turn, resulted in elevated adherence of P. gingivalis. CONCLUSION: The data indicate that the method closely reflects co-aggregation characters, and that Fus. nucleatum has a positive effect on the adherence of P. gingivalis. SIGNIFICANCE AND IMPACT OF THE STUDY: The present method, which is designed to mimic the oral environment, should prove useful in the semi-quantitative evaluation of co-aggregation reactions.

Bacterial Adhesion↗
PubMed2006

State-dependent conformations of the translocation pathway in the tyrosine transporter Tyt1, a novel neurotransmitter:sodium symporter from Fusobacterium nucleatum.

The gene of a novel prokaryotic member (Tyt1) of the neurotransmitter:sodium symporter (NSS) family has been cloned from Fusobacterium nucleatum. In contrast to eukaryotic and some prokaryotic NSSs, which contain 12 transmembrane domains (TMs), Tyt1 contains only 11 TMs, a characteristic shared by approximately 70% of prokaryotic NSS homologues. Nonetheless upon heterologous expression in an engineered Escherichia coli host, Tyt1 catalyzes robust Na+-dependent, highly selective l-tyrosine transport. Genetic engineering of Tyt1 variants devoid of cysteines or with individually retained endogenous cysteines at positions 18 or 238, at the cytoplasmic ends of TM1 and TM6, respectively, preserved normal transport activity. Whereas cysteine-less Tyt1 was resistant to the inhibitory effect of sulfhydryl-alkylating reagents, N-ethylmaleimide inhibited transport by Tyt1 variants containing either one or both of the endogenous cysteines, and this inhibition was altered by the substrates sodium and tyrosine, consistent with substrate-induced dynamics in the transport pathway. Our findings support a binding model of Tyt1 function in which an ordered sequence of substrate-induced structural changes reflects distinct conformational states of the transporter. This work identifies Tyt1 as the first functional bacterial NSS member putatively consisting of only 11 TMs and shows that Tyt1 is a suitable model for the study of NSS dynamics with relevance to structure/function relationships of human NSSs, including the dopamine, norepinephrine, serotonin, and gamma-aminobutyric acid transporters.

Amino Acid Sequence↗
PubMed2001

Fusobacterium prausnitzii and related species represent a dominant group within the human fecal flora.

The human gut microflora plays a key role in nutrition and health. It has been extensively studied by conventional culture techniques. However these methods are difficult, time consuming and their results not always consistent. Furthermore microscopic counts indicate that only 20 to 40% of the total flora can be cultivated. Among the predominant species of the human gut, Fusobacterium prausnitzii was reported either as one of the most frequent and numerous species or was seldom retrieved. We designed and validated a specific rRNA-targeted oligonucleotide probe, called S-*-Fprau-0645-a-A-23, to accurately detect and quantify F. prausnitzii and relatives within the human fecal microflora. The target group accounted for 5.3 +/- 3% of total bacterial 16S rRNA using dot blot hybridization (10 human fecal samples) and 16.5 +/- 7% of cells stained with Dapi using in situ hybridization (10 other human fecal samples). A specific morphology seemed to be typical and dominant: two cells forming an asymmetrical double droplet. This work showed that F. prausnitzii and phylogenetically related species represent a dominant group within the human fecal flora.

Adult↗
PubMed1993

Measurement of electrical bioimpedance for studying utilization of amino acids and peptides by Porphyromonas gingivalis, Fusobacterium nucleatum, and Treponema denticola.

The growth response of Porphyromonas gingivalis, Fusobacterium nucleatum, and Treponema denticola to peptides (supplied as trypticase) and amino acids (supplied as casamino acids) was measured over 24 hours by monitoring changes in alternating-current conductivity at 37 degrees C. All species utilized peptides preferentially over amino acids. These results are consistent with those obtained previously with conventional growth-response experiments. The duration of the linear growth response to trypticase of P. gingivalis was 9.7 hours, whereas that of both F. nucleatum and T. denticola was > 24 hours. By contrast, there was more uniformity in the utilization of amino acids from the casamino acid mixture, which previously has been shown to be a poor growth substrate. Furthermore, subtle differences in growth patterns, such as the ability of F. nucleatum to metabolize its storage glycopolymers before utilizing amino acids, were clearly evident. The present method provides an excellent means of studying bacterial growth kinetics and delineating bacterial/substrate specificities of both synthetic and natural substrates.

Amino Acids↗
PubMedDate not supplied

Activation of Hageman factor by lipopolysaccharides of Bacteroides fragilis, Bacteroides vulgatus, and Fusobacterium mortiferum.

Preincubation of lipopolysaccharides (LPS) of Bacteroides fragilis, Bacteroides vulgatus, and Fusobacterium mortiferum with purified human Hageman factor (HF) followed by addition of purified human prekallikrein resulted in the activation of HF, as measured by the generation of kallikrein using the tripeptide substrate N-alpha-benzoyl-L-proline-L-phenylalanine-L-arginine-4-nitroanilide. Addition of purified HF, which had been preincubated with the LPS, to HF-deficient plasma resulted in the acceleration of the recalcification time. Addition of the LPS to HF-deficient plasma reconstituted with various concentrations of HF also resulted in the acceleration of the recalcification time; the magnitude of the acceleration correlated with the amount of HF used to reconstitute the deficient plasma. These results demonstrate that LPS of selected gram-negative anaerobes activate HF and thereby initiate the intrinsic pathway of coagulation.

Bacteroides↗
PubMed1985

Characterization of a new beta-lactamase from Fusobacterium nucleatum by substrate profiles and chromatofocusing patterns.

Seven beta-lactamase-producing Fusobacterium nucleatum strains were isolated from patients with recurrent tonsillitis. The isolates were highly resistant to phenoxymethylpenicillin, benzylpenicillin, ampicillin, piperacillin and cloxacillin. They were all sensitive to cefaclor, cephaloridine, cefotaxime, cefoxitin, latamoxef (moxalactam) and imipenem. Penicillinase activity was found intracellularly after 20 h incubation. Specific activity of the unpurified penicillinase varied among the strains between 0.24-9.3 U/mg protein. The enzyme hydrolysed ampicillin and benzylpenicillin more rapidly than piperacillin. Cephalothin and imipenem were hydrolysed at rates less than 1% of benzylpenicillin. Chromatofocusing experiments eluted the beta-lactamases from all strains at a single peak between pH 5.1-5.2.

Anti-Bacterial Agents↗
PubMed1992

Effect of clavulanic acid, sulbactam and tazobactam on three different beta-lactamases from Bacteroides uniformis, Clostridium butyricum and Fusobacterium nucleatum.

The effect of three beta-lactamase inhibitors, clavulanic acid, sulbactam and tazobactam used in clinical practice were compared for their activity against purified beta-lactamases from Bacteroides uniformis, Clostridium butyricum and Fusobacterium nucleatum. The enzymes from B. uniformis and C. butyricum were produced in fermenters under controlled growth conditions and the enzyme from F. nucleatum was produced in batch cultures. Purification of the beta-lactamases was achieved by anion-exchange chromatography, gel filtration and FPLC-technique. The degree of inactivation of beta-lactamase activity was determined spectrophotometrically with nitrocefin as the substrate. The inhibitors in various concentrations were preincubated at 30 degrees C together with the enzyme for different time periods (0.5-120 min) before determination of the remaining beta-lactamase activity. The inhibitors all decreased the activity of the beta-lactamases investigated. Clavulanic acid and sulbactam were capable of reducing the enzyme activity of the B. uniformis beta-lactamase more effectively than the C. butyricum and F. nucleatum beta-lactamases. All beta-lactamases tested were more susceptible to tazobactam than to clavulanic acid and sulbactam.

Bacteroides↗
PubMed1997

Immune response to Fusobacterium nucleatum, Prevotella intermedia and other anaerobes in children with acute tonsillitis.

The number of aerobic and anaerobic bacteria was determined in the saliva of 20 children with acute group A beta-haemolytic streptococcal (GABHS) pharyngo-tonsillitis, and 20 with acute non-GABHS tonsillitis. Antibody titres to four Gram-negative anaerobic bacilli that reside in the oropharynx (Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans) were determined in these and 20 control patients. An average of 8.8 aerobic and anaerobic isolates per patient saliva specimens were found during the acute tonsillitis stage in both groups, and 6.9 (in GABHS tonsillitis) and 5.6 (in non-GABHS tonsillitis) 5-6 weeks later. There were 10- to 1000-fold more bacteria in the acute stages of the inflammation in both GABHS and non-GABHS groups. These bacteria were Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, Peptostreptococcus spp., F. nucleatum, Prevotella spp. and Porphyromonas spp. Significantly higher antibodies levels to F. nucleatum and P. intermedia were found in the second serum sample of patients with non-GABHS pharyngo-tonsillitis (P < 0.001) and GABHS tonsillitis (P < 0.05), as compared with their first sample or the levels of antibodies in controls. The increase in the number of several aerobic and anaerobic bacteria during acute tonsillitis and the increase in antibody levels to F. nucleatum and P. intermedia, known oral pathogens, may suggest a possible pathogenic role for these organisms in acute non-GABHS and GABHS tonsillitis.

Acute Disease↗
PubMed2003

Emergence of penicillin resistance among Fusobacterium nucleatum populations of commensal oral flora during early childhood.

Penicillin resistance due to beta-lactamase production is surprisingly common among oral bacteria in childhood. Fusobacterium nucleatum, a Gram-negative anaerobic bacillus, is a member of the developing oral commensal flora. As part of the investigation on the emergence of oral bacterial resistance, the aim of the present study was to examine longitudinally the penicillin resistance among salivary F. nucleatum populations as related to age, day care attendance and sibling history, and exposure to antimicrobial agents. Altogether 1492 F. nucleatum isolates from saliva of 44 healthy infants followed at a study clinic at 2, 6, 12, 18 and 24 months of age were tested for beta-lactamase production. Furthermore, the 276 beta-lactamase-positive isolates were examined for their in vitro susceptibility to penicillin G by the NCCLS-approved agar dilution method. Statistical analysis of the associations between penicillin-resistant isolates and infants' age, day care attendance, number of siblings and their ear infections, and exposure to antimicrobial agents was performed by SPSS Windows Version 10. The prevalence of infants harbouring beta-lactamase-producing F. nucleatum strains increased from 2% to 49% during the follow-up time. In nearly all cases beta-lactamase-producing F. nucleatum isolates were found simultaneously with beta-lactamase-negative isolates. Most beta-lactamase-producing isolates (80%) showed an MIC of > or =8 mg/L. In conclusion, the prevalence of infants harbouring penicillin-resistant F. nucleatum due to beta-lactamase production increased with age and usage of antimicrobial agents during the first year of life.

Anti-Bacterial Agents↗
PubMed2000

The human gut bacteria Bacteroides thetaiotaomicron and Fusobacterium varium produce putrescine and spermidine in cecum of pectin-fed gnotobiotic rats.

Pectin is a soluble indigestible polysaccharide that stimulates cecal polyamine formation in rats. Bacteroides and fusobacteria, two numerically dominant bacterial population groups in the large intestine, were found to synthesize in vitro high amounts of spermidine and putrescine. The purpose of this study was to elucidate the effect of pectin on the polyamine production by defined bacterial species in vivo. Germfree male Wistar rats (n = 18) were randomly assigned to one of three treatments: (i) monoassociation with Bacteroides thetaiotaomicron + fiber-free diet; (ii) diassociation with B. thetaiotaomicron + Fusobacterium varium + fiber-free diet or (iii) diassociation with B. thetaiotaomicron + F. varium + fiber-free diet + 10% pectin. The cecal contents of monoassociated rats fed fiber-free diet contained large amounts (1.51+/-0.21 micromol/dry total cecum content) of spermidine which was the major polyamine. The cecum of diassociated rats fed the fiber-free diet contained even higher concentrations of spermidine (2.53+/-0.21 micromol/dry total cecum content) and also putrescine, which was now the dominant polyamine (putrescine 0.32+/-0.28 vs. 3.01+/-0.28 micromol/dry total cecum content; monoassociation vs. diassociation). Pectin consumption by diassociated rats led to an additional increase in the cecal concentrations of all polyamines: putrescine, spermidine and spermine were 40, 37 and 100%, respectively, higher in the diassociated rats consuming the pectin diet than in those consuming the pectin-free diet. Since the microbial counts in the cecum did not differ in the diassociated treatment groups, the elevated concentrations of polyamines observed in the pectin group must have been due to stimulated bacterial polyamine synthesis. The decline of individual polyamines from cecum to feces detected at the end of the study in all treatment groups and the high microbial counts in the cecum and in feces suggest that bacterial polyamines are absorbed in cecum and colon. Pectin stimulates intestinal microbes to synthesize large amounts of polyamines which may be utilized by the host.

Analysis of Variance↗
PubMed2005

Universal DNA primers amplify bacterial DNA from human fetal membranes and link Fusobacterium nucleatum with prolonged preterm membrane rupture.

A large number of bacterial species have been identified in fetal membranes after preterm labour (PTL) associated with intrauterine infection by microbiological culture. In this study, we have investigated a molecular and bioinformatic approach to organism identification which surmounts the need for specific and diverse microbiological culture conditions required by conventional methods. Samples of fetal membranes were taken from 37 preterm infants, and 6 normal term controls delivered by caesarean section, in which bacteria had been detected by in situ hybridization of 16S ribosomal RNA using a generic probe. Degenerate primers were designed to amplify bacterial 16S ribosomal DNA by PCR and used to amplify bacterial DNA from human fetal membranes. Amplicons were cloned, sequenced and bacteria were identified bioinformatically by comparison of sequences with known bacterial DNA genomes. In situ hybridization using an organism specific probe was then used to confirm the presence of the commonest identified organism in tissue samples. Bacterial DNA amplified from 15/43 samples, all from preterm deliveries, and the bioinformatic approach identified organisms in all cases. Multiple bacteria were identified including Mycoplasma hominis, Pasturella multocida, Pseudomonas PH1, Escherichia coli and Prevotella bivia. The commonest organism Fusobacterium nucleatum was found in 9/15 (60%) of samples. Ten of the 12 samples obtained after prolonged membrane rupture were positive for bacterial DNA, and 7 of these (70%) contained DNA from F. nucleatum. Bacteria from fetal membranes may be identified by molecular and bioinformatic methods. Further work is warranted to investigate the apparent linkage between F. nucleatum, fetal membrane rupture and preterm delivery.

Bacterial Typing Techniques↗
PubMed1979

Site specific endonuclease from Fusobacterium nucleatum.

Four different isolates of Fusobacterium nucleatum (A,C,D and E) contain restriction endonucleases of differing specificity. Whilst many of the endonucleases are isochizomers of known enzymes, two novel activities are Fnu DII which recognizes and cleaves the sequence 5'-CGCT-3'/3'-GCGC-5' AND Fnu EI which recognizes and cleaves the sequence 5'-GATC-3'/3'-CTAG-5' irrespective of the extent of methylation of the adenine residues.

Base Sequence↗
PubMedDate not supplied

Fusobacterium osteomyelitis and pyarthrosis: a classic case of Lemierre's syndrome.

Lemierre's syndrome, a systemic anaerobic infection caused by Fusobacterium necrophorum, is characterized by an acute oropharyngeal infection, septic thrombophlebitis of the internal jugular vein, sepsis, and multiple metastatic infections. It commonly leads to septic arthritis and occasionally to osteomyelitis. In the preantibiotic era, this infection was nearly universally fatal. Today it still poses a potentially grave threat to the young patients affected. Prompt recognition with appropriate debridement and antibiotic treatment results in complete recovery in most cases. We report a case of anaerobic septic arthritis and multifocal acute hematogenous osteomyelitis as part of a classic presentation of Lemierre's syndrome.

Adolescent↗
PubMed1994

Phylogenetic relationship of Fusobacterium necrophorum A, AB, and B biotypes based upon 16S rRNA gene sequence analysis.

The 16S rRNA genes from virulent (AB) and benign (B) biotype strains of Fusobacterium necrophorum, the causative agent of ovine foot abscess, were cloned and sequenced. Notwithstanding the distinct phenotypic differences between the AB and B biotypes, a phylogenetic analysis in which the 16S rRNA gene sequences were used revealed the close relationship of these taxa. Comparison of the virulent and benign biotypes of F. necrophorum may therefore be a legitimate way to identify key virulence factors useful in vaccine development.

Bacterial Typing Techniques↗