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PubMed2004

Characterization of Tn916S, a Tn916-like element containing the tetracycline resistance determinant tet(S).

We have characterized a transferable tetracycline resistance (Tcr) element from a Streptococcus intermedius isolate. The gene responsible for this resistance was identified by PCR and Southern hybridization as tet(S). Furthermore, the genetic support for this determinant was shown to be a conjugative transposon closely related to Tn916. This element has been designated Tn916S.

Base Sequence↗

PubMed2006

A new checkerboard panel for testing bacterial markers in periodontal disease.

BACKGROUND/AIMS: Various microbiological methods have been used for testing bacterial markers for periodontitis and periodontal disease progression. Most studies have used only a limited number of well recognized bacterial species. The purpose of the present study was to evaluate the association of 13 more recently identified bacterial species in a new panel in comparison with 12 previously more recognized periodontotopathogens ('old panel') using the 'checkerboard' DNA-DNA hybridization method. METHODS: Fifty individuals were chosen who showed at least one site with a probing pocket depth of 6 mm or more (disease) and bleeding on probing and at least one site with a probing pocket depth of 3 mm and without bleeding on probing (health). One diseased and one healthy site on each individual were sampled with the paperpoint technique and the samples were processed in the checkerboard technique against deoxigenin-labeled whole genomic probes to 25 subgingival species representing 12 well recognized and 13 newly identified periodontitis associated species. RESULTS: Twenty-four (out of 25) species were detected more frequently in the subgingival plaque of diseased than healthy sites both at score 1 (> 10(4)) and score 3 (> 10(5)). A significant difference at the higher score (score 3) was noticed for all species of the old panel except for three (Streptococcus intermedius, Selenomonas noxia, and Eikenella corrodens). Of the species in the new panel only Prevotella tannerae, Filifactor alocis, and Porphyromonas endodontalis showed a statistical significant difference between diseased and healthy sites. CONCLUSION: It was concluded that P. tannerae, F. alocis, and P. endodontalis should be added to the 12 species used for routine diagnostics of periodontitis-associated bacterial flora.

Adolescent↗

PubMed2005

Antibacterial action of photoactivated disinfection {PAD} used on endodontic bacteria in planktonic suspension and in artificial and human root canals.

OBJECTIVES: To measure antibacterial action of photoactivated disinfection (PAD) on endodontic bacteria in planktonic suspension and root canals. METHODS: Four bacteria, Fusobacterium nucleatum,Peptostreptococcus micros, Prevotella intermedia and Streptococcus intermedius, were tested in suspension. After mixing equal volumes of Tolonium chloride and bacterial suspension for 60s, each 200 microL of concentration (>10(6)cfu mL(-1)) was irradiated with light at 633+/-2 nm. Each energy dose/Tolonium chloride concentration combination was tested eight times, with controls. Prepared root canals in Training Blocs and extracted human teeth were inoculated with S. intermedius followed by 10 mg L(-1) Tolonium chloride or saline. Bacteria in canals were sampled before and after light irradiation. Student t-test assessed significance of changes in viable bacteria produced by treatment of either light or Tolonium chloride alone and light/Tolonium chloride combinations. RESULTS: In suspension, reductions in bacteria were highly significant (P<0.01) for light/Tolonium chloride combinations compared to light or Tolonium chloride alone. Maximum mean log reductions of 1.14 (P. intermedia), 2.48 (P. micros), 2.81 (F. nucleatum) and 6.73 (S. intermedius) were at 4.8 J/20 mg L(-1). Antibacterial action was increased by energy dose increase (not always significantly), but not by Tolonium chloride concentration. In control canals mean log reductions of 0.42 (Blocs) and 0.38 (teeth) from initial levels were not significant. PAD mean log reductions of 2.40 (Blocs) and 2.01 (teeth) were highly significant. Changes for PAD/energy dose combinations were not significant. CONCLUSION: PAD killed endodontic bacteria at statistically significant levels compared to controls. Kills varied with bacterial species.

Anti-Bacterial Agents↗

PubMed2004

Crystallization and preliminary X-ray analysis of the human-specific toxin intermedilysin.

Intermedilysin is a human-specific toxin from Streptococcus intermedius, which is part of normal human oral flora. The bacterium is an opportunistic pathogen with a tendency for deep-seated infection in the brain and liver. Intermedilysin belongs to the cholesterol-dependent cytolysin (CDCs) family of toxins, which have been identified in several different bacteria including the serious human pathogens S. pneumoniae and Clostridium perfringens. Intermedilysin, however, is the only member that shows exclusive specificity for human cells. The toxin has a couple of non-conservative amino-acid substitutions in a tryptophan-rich region of the molecule (Cys to Ala and Trp to Pro), the most conserved region amongst the CDCs. Mutations in this region are known to render other CDCs inactive. In order to investigate the structure-function relationships of the unusual features of intermedilysin, which will help us to understand the molecular mechanism of the toxin family in general, recombinant intermedilysin has been crystallized. The crystals belong to an orthorhombic space group and contain two molecules per asymmetric unit. Diffraction data were collected to 2.3 A using synchrotron radiation.

Bacterial Proteins↗

PubMed2005

Clinical, phenotypic, and genotypic evidence for Streptococcus sinensis as the common ancestor of anginosus and mitis groups of streptococci.

In 2002, we reported the discovery of a novel species of viridans streptococcus, Streptococcus sinensis. Recently, we reported the isolation of two more strains of S. sinensis. Clinically, S. sinensis is a definite cause of infective endocarditis, a characteristic mainly pertaining to the mitis group of streptococci. Phenotypically, two of the three S. sinensis isolates were Lancefield group F, a characteristic of the anginosus group. However, none of the three strains possess the caramel smell typical of this group of streptococci. Biochemically, S. sinensis was identified in 56% of the time as members of the anginosus group, and in 33% of the time as members of the mitis group. These clinical and phenotypic properties should be governed by the presence/absence or expressivity of particular genes in the S. sinensis genome. Genotypically, phylogenetic analysis using 16S rRNA gene sequences showed that S. sinensis branched out as the first branch in the anginosus group, implying that it is the ancestor of the other members of this group. However, the bootstrap value for S. sinensis clustered with members of the anginosus group is only 47%, meaning that it is often not clustered with members of this group, but the mitis group. Furthermore, the differences in the 16S rRNA gene sequences between S. sinensis and Streptococcus intermedius (3.7%) and those between S. sinensis and Streptococcus gordonii (3.6%) are almost the same. All these indicated that it is very likely that S. sinensis is the common ancestor of the anginosus and mitis groups of streptococci. Complete genome sequencing of S. sinensis and comparative genomics studies on the S. sinensis genome and genomes of members in the anginosus and mitis groups should reveal clues to the underlying genotypic differences that govern the different phenotypic properties of the two groups of streptococci, such as why streptococci of the anginosus group are prone to cause abscess formation but not infective endocarditis as compared to other viridans streptococci.

Genotype↗

PubMed2001

Mannosidase production by viridans group streptococci.

The production of mannosidase activity by all currently recognized species of human viridans group streptococci was determined using an assay in which bacterial growth was dependent on the degradation of the high-mannose-type glycans of RNase B and subsequent utilization of released mannose. RNase B is an excellent substrate for the demonstration of mannosidase activity since it is a glycoprotein with a single glycosylation site which is occupied by high-mannose-type glycoforms containing five to nine mannose residues. Mannosidase activity was produced only by some members of the mitis group (Streptococcus mitis, Streptococcus oralis, Streptococcus gordonii, Streptococcus cristatus, Streptococcus infantis, Streptococcus parasanguinis, and Streptococcus pneumoniae) and Streptococcus intermedius of the anginosus group. None of the other species within the salivarius and mutans groups or Streptococcus peroris and Streptococcus sanguinis produced mannosidase activity. Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry, it was demonstrated that the Man(5) glycan alone was degraded while Man(6) to Man(9), which contain terminal alpha(1-->2) mannose residues in addition to the alpha(1-->3), alpha(1-->6), and beta(1-->4) residues present in Man(5), remained intact. Investigations on mannosidase production using synthetic (4-methylumbelliferone- or p-nitrophenol-linked) alpha- or beta-mannosides as substrates indicated that there was no correlation between degradation of these substrates and degradation of the Man(5) glycan of RNase B. No species degraded these alpha-linked mannosides, while degradation of the beta-linked synthetic substrates was restricted to strains within the Streptococcus anginosus, S. gordonii, and S. intermedius species. The data generated using a native glycoprotein as the substrate demonstrate that mannosidase production within the viridans group streptococci is more widely distributed than had previously been considered.

Culture Media↗

PubMed1983

Bacteriology of dental abscesses of endodontic origin.

Aspirates have been cultured from 10 dental abscesses of endodontic origin, all of which had penetrated beyond the bony alveolus to produce fluctuant swelling. Sampling was by syringe aspiration. Strict anaerobic techniques, including the use of an anaerobic chamber, were used for serial dilution and plating. Randomly selected colonies (100) from each culture were purified, characterized, and identified. Seventy percent of the bacterial isolates were either strict anaerobes or microaerophilic. One abscess yielded a pure culture of a viridans streptococcus, Streptococcus milleri. Streptococcus intermedius dominated the flora in a second abscess. The common oral streptococcus, Streptococcus sanguis, constituted only 2% of the isolates from one additional infection. Fusobacterium nucleatum, Bacteroides melaninogenicus, other Bacteroides including B. oralis and B. ruminicola, anaerobic diphtheroids, Peptostreptococcus micros, and Staphylococcus epidermis were other predominant isolates.

Bacteria, Anaerobic↗

PubMed1988

The synergistic effect of cefotaxime and desacetylcefotaxime against clinical isolates of anaerobic bacteria.

The synergistic interaction of cefotaxime and desacetylcefotaxime against 187 clinically significant anaerobic organisms was investigated. Fusobacterium nucleatum, Actinomyces odontolyticus, propionibacteria, lactobacilli, peptostreptococci, Streptococcus intermedius and Veillonella were sensitive to cefotaxime. Both Eubacterium lentum and Streptococcus morbillorum were resistant. The susceptibility of the clostridia varied from 0.125 to greater than 256 mg/L; only 20% of species demonstrated synergy between cefotaxime and desacetylcefotaxime. The minimum inhibitory concentration (MIC) of cefotaxime against members of the genus Bacteroides ranged from 0.0625 to greater than 256 mg/L. The MIC50 of cefotaxime to Bacteroides fragilis and B. vulgatus was lowered from 6 and 4 mg/L, respectively, to 2 and 1 mg/L, respectively, when 4 mg/L desacetylcefotaxime was added to the medium. Full or partial synergy was demonstrated by 50.7% of the Bacteroides species tested. While cefotaxime and desacetylcefotaxime act synergistically against many members of the genus Bacteroides, the MIC of at least 10% of strains is not affected by this combination.

Bacteria, Anaerobic↗

PubMed1990

Species-specific oligodeoxynucleotide probes for the identification of periodontal bacteria.

Oligodeoxynucleotide probes were developed for identification of the periodontal bacteria Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, B. intermedius types I and II, B. forsythus, Eikenella corrodens, Fusobacterium nucleatum, Haemophilus aphrophilus, Streptococcus intermedius, and Wolinella recta. Probes were designed by sequencing the 16S rRNA for each bacterium, identifying hypervariable regions, and chemically synthesizing species-specific probes. These probes were specific when tested against a panel of nucleic acids from closely related bacteria.

Bacteria↗

PubMed2003

Subgingival microbiota levels and their associations with periodontal status at the sampled sites in an adult Sudanese population using miswak or toothbrush regularly.

Little information is available on the effect of miswak use on gingival microbiota. We assessed levels of 28 oral bacteria in subgingival plaque of adult Sudanese miswak (n = 38) and toothbrush users (n = 36) age range 20-53 years (mean 34.6 years) to study associations between these bacteria, oral hygiene method, and periodontal status at the sampled sites. A pooled subgingival plaque sample from 6 probing sites of 1 selected tooth in each jaw was obtained from each subject. Whole genomic DNA probes and the checkerboard DNA-DNA hybridization were used in assessing 74 pooled samples. Using 10(5) bacterial cells threshold, between 2.6% and 47.4% of miswak users and between 2.8% and 36.1% of toothbrush users harbored the investigated species. The percentages of subjects with the investigated species at 10(6) bacterial cells varied between 2.6% and 39.5% in miswak and between 2.8% and 36.1% in toothbrush users. Miswak users harbored significantly higher Streptococcus intermedius, Actinobacillus actinomycetemcomitans, Veillonella parvula, Actinomyces israelii, and Capnocytophaga gingivalis, and significantly lower Selenomonas sputigena, Streptococcus salivarius, Actinomyces naeslundii, and Streptococcus oralis than did toothbrush users. Probing pocket depth > or = 6 mm showed significantly (P < 0.05) higher levels of Porphyromonas gingivalis, Treponema denticola, Bacteroides forsythus, Fusobacterium nucleatum, and V. parvula than those 4-5 mm. Our results indicate that the type of oral hygiene had a significant effect on levels of 11 out of 28 bacterial species, and that the type of effect was also dependent on type of bacteria and probing pocket depth.

Actinomyces↗

PubMed1993

Bactericidal effects of povidone-iodine solution to oral pathogenic bacteria in vitro.

Seven species of periodontal pathogenic bacteria (Bacteroides, gingivalis, Bacteroides intermedius, Bacteroides melaninogenicus, Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans, Capnocytophaga spp., Eikenella corrodens) and two control species (Streptococcus intermedius, Pseudomonas aeruginosa) were selected in order to study the bactericidal effects of 10% povidone-iodine (PVP-I) aqueous solution in vitro. The PVP-I solution was diluted to 10, 20, 50, 100, 200, 400, 800, 1600, 3200, 6400 and 12800 x and contact times were 15, 30 and 60 seconds. The strongest bactericidal effects on the seven periodontal pathogenic bacteria and two control bacteria were seen at a dilution of 400 x and a contact time of 15 seconds. Based on these findings, we advocate a 0.25% solution of 10% aqueous PVP-I for oral mucosa and periodontal pocket irrigation.

Aggregatibacter actinomycetemcomitans↗

PubMed1978

Inhibitory effects of extracellular products from oral bacteria on human fibroblasts and stimulated lymphocytes.

Extracellular products of 12 strains of Streptococcus mutans and 5 additional species of oral bacteria were analyzed for their ability to inhibit proliferation of fibroblastoid cells (HeLa and AV3) and blast transformation of human peripheral blood lymphocytes obtained from normal individuals. Products from S. mutans strains AHT and BHT, Streptococcus intermedius, and Actinomyces viscosus inhibited [3H]thymidine uptake by fibroblastoid cells and phytohemagglutinin-stimulated lymphocytes. Products from S. mutans E49, Streptococcus salivarius, and Actinomyces naeslundii inhibited blast transformation of human lymphocytes but did not significantly inhibit the growth of fibroblastoid cells. Preparations from S. intermedius gave the greatest inhibitory activity against both target cell types; initial characterization of this preparation suggested a single factor active in both assays, in that the heat lability and Sephadex G-200 elution profile were similar for the inhibitory activity seen with the two cell types. The molecular weight of the inhibitor, estimated by gel filtration on Sephadex G-200 and Ultragel AcA34, was approximately 160,000. The results strongly suggest that oral bacteria produce heat-labile substances that interfere with fibroblast proliferation and alter the lymphocytic immunological response.

Actinomyces↗

PubMed1979

Differentiation of Peptococcus and Peptostreptococcus by gas-liquid chromatography of cellular fatty acids and metabolic products.

Gas-liquid chromatographic (GLC) profiles of cellular fatty acids and metabolic products were useful in identifying strains of Peptococcus saccharolyticus, Peptococcus asaccharolyticus, Peptostreptococcus anaerobius, Peptostreptococcus micros, and Streptococcus intermedius. The GLC results supported the recent taxonomic decision to transfer aerotolerant Peptostreptococcus species to the genus Streptococcus. Because inconsistencies in the results prevented our differentiating Peptococcus prevotii. Peptococcus magnus, and Peptococcus variabilis by GLC, additional strains will have to been examined. These GLC techniques are amenable to routine use; however, for interlaboratory results to be meaningful, the classification and nomenclature of the anaerobic gram-positive cocci should be standardized.

Amines↗

PubMed1990

[Anaerobic bacteria detected in inflammatory conditions of the respiratory tract].

In this study a participation of anaerobic bacteria in respiratory tract diseases is presented. Bronchial washings collected by ++fibrobronchoscope constituted material for the study. Immediately after collection the material was plated onto two media for aerobic bacteria (hemomedium) and anaerobic bacteria (anaeromedium). Then, the samples were centrifuged and a sediment was plated on solid media suitable for aerobic and anaerobic bacteria. Bacterial anaerobic isolates were identified by using API 20E and their sensitivity to antibiotics was tested. From the material described above the most frequently isolated anaerobic bacteria were such as: Streptococcus intermedius, Bacteroides melaninogenicus, Veilonella sp. Among aerobic bacteria the most frequently isolated were Gram-negative rods, Streptococcus faecalis, Branhamella catarrhalis. It is worth to underline that in about 25% of cases anaerobic bacteria were the only isolates.

Anti-Bacterial Agents↗

PubMed1985

Survival analysis of periodontal sites before and after periodontal therapy.

Periodontal diseases appear to progress with bursts of destructive activity at individual sites. One effect of treatment might be to diminish the frequency of such bursts. Survival analysis was employed to seek such effects on the periodontal sites of 16 individuals with prior evidence of destructive periodontal disease. The subjects were monitored at bi-monthly intervals and actively breaking down sites were detected using attachment level measurements and the tolerance method of analysis. When active sites were detected, control sites of equal pocket depth and attachment loss were selected and microbiological and immunological samples were taken. The subjects were treated by modified Widman flap surgery and systemically administered tetracycline. On completion of therapy, bi-monthly monitoring was reinstituted. Life tables were constructed for periodontal sites in each of the 16 subjects prior to and after therapy. A site losing more than 3 mm of attachment at any time interval was considered to have relapsed or "died". Survivor functions were calculated for each time period indicating the % of sites which survived at any time. The subjects were divided into 3 categories on the basis of post-therapy survivor functions. The annual hazard rate in 9 good treatment response subjects (group 1) was reduced from 0.10/year to 0.01/year. The hazard rate of 5 intermediate treatment response subjects (group 2A) was reduced from 0.16/year to 0.04/year and that of 2 poor treatment response subjects (group 2B) from 0.15/year to 0.07/year. Group 2A and 2B individuals were combined and differences were sought in clinical, microbiological and immunological parameters between the good and poor treatment response groups. 5 out of 7 of the poor responding individuals showed elevated humoral antibody responses to 3 or more gram-negative subgingival species tested. Many of the elevated responses in this group were to organisms which are widely distributed and return quickly after therapy such as Fusobacterium nucleatum, Eikenella corrodens, Bacteroides intermedius and Capnocytophaga sputigena. The predominant cultivable microbiota in subgingival samples taken prior to therapy from the good responding group had significantly greater proportions of Actinobacillus actinomycetemcomitans, C. ochracea and B. intermedius than the poor responding group. The latter group showed significantly elevated proportions of F. nucleatum, Peptostreptococcus micros and Streptococcus intermedius.

Adolescent↗

PubMed1985

The relationships between streptococcal species and periodontopathic bacteria in human dental plaque.

The existence of antagonistic and commensal relationships between microorganisms was investigated. The predominant cultivable flora in 172 plaque samples from active and non-active sites in 32 human subjects with destructive periodontitis was determined. The presence of putative periodontopathic organisms (Bacteroides gingivalis, Bacteroides intermedius, Bacteroides forsythus, Wolinella recta, Actinobacillus actinomycetemcomitans, and Eikenella corrodens) in a site was correlated with the absence of certain viridans streptococci (Streptococcus sanguis, Streptococcus uberis and Streptococcus intermedius), and vice versa. A strong commensal relationship was found between B. gingivalis and Strep. intermedius. The second study involved 3 subjects with intractable periodontitis whose plaque harboured large numbers of one or more of these periodontopathic organisms. This plaque contained fewer organisms capable of inhibiting the growth of the periodontopathic strains in vitro when compared with a clinically-healthy control subject. Intermediate levels of inhibitors were found in plaque taken from non-active lesions. The majority of inhibitors in plaque from the healthy control were viridans streptococci. Hydrogen-peroxide production by these organisms appears to be the principal mechanism of growth inhibition for periodontopathic organisms. Bacterial interactions may thus be causally related to both periodontal health and disease.

Actinobacillus↗

PubMed1988

Serious infections due to penicillin-resistant strains of viridans streptococci with altered penicillin-binding proteins.

We investigated the mechanism of resistance to penicillin in two penicillin-resistant clinical isolates of viridans streptococci that caused life-threatening infections in two patients not receiving chronic penicillin therapy. The first was a strain of Streptococcus intermedius that was isolated from the cerebrospinal fluid of a patient with post-neurosurgical meningitis. The second was a strain of Streptococcus mitis recovered from the bloodstream of a leukemic patient with neutropenia. Both patients failed to respond to penicillin. The mechanism of resistance in these strains was associated with diminished affinity for penicillin of their penicillin-binding proteins, as compared with those of penicillin-susceptible control strains. We conclude that penicillin-resistant viridans streptococci may cause serious infections even in patients not receiving chronic penicillin therapy, that this resistance is clinically significant and may result in failure of penicillin therapy, and that the mechanism of resistance in these strains is associated with diminished affinity of the penicillin-binding proteins for penicillin.

Adult↗

PubMed2001

Association of early onset periodontitis microbiota with aspartate aminotransferase activity in gingival crevicular fluid.

OBJECTIVES: The objective of this study was to determine the relationship between the activity of the enzyme aspartate aminotransferase (AST) in gingival crevicular fluid (GCF) using the colorimetric PerioGard (PTM) test and the subgingival microflora in early onset periodontitis lesions. MATERIAL AND METHODS: The study population consisted of 25 otherwise healthy individuals exhibiting early onset periodontitis (EOP). In each patient four experimental sites were identified comprising one deep periodontal pocket (PD >5 mm) randomly chosen in each quadrant. Bacterial samples were obtained from the experimental sites, consecutively cultured anaerobically and in 10% CO(2) using selective and nonselective media. Isolates were characterized to species level by conventional biochemical tests and various identification kits. Clinical measurements as well as AST activity, assessed either as positive or negative using the PTM, were recorded at the same sites. RESULTS: Sixty-two sites exhibited AST positive and 38 AST negative activity. Analysis of bacterial counts using the ANOVA (Mann Whitney U-test) showed that Streptococcus intermedius, Peptostreptococcus micros, Campylobacter concisus, Bacteroides forsythus, Camplobacter gracilis, Campylobacter rectus and Selenomonas sputigena were significantly higher in sites with AST-positive activity. The odds ratio of having high prevalence of S. intermedius, P. micros, C. concisus, B. forsythus, C. gracilis, C. rectus and S. sputigena in the presence of a positive AST site was very high (range: 3.5-17.0). Streptococcus sanguis, Actinomyces naeslundii, Gemella morbillorum, Capnocytophaga gingivalis, Veillonella parvula, Fusobacterium varium, Eubacterium lentum and Prevotella oralis were detected in significantly higher proportions in sites with AST negative activity and manifested a negative odds ratio in the presence of AST positive sites. The logistic regression analysis revealed that smoking and bleeding upon probing showed a significant association with AST activity, while plaque and suppuration were not found to be significant predictors of AST activity. The co-infection of Porphyromonas gingivalis, B. forsythus and P. micros, or P. gingivalis, B. forsythus and C. rectus were found to be significantly associated with the AST activity (p<0.001). AST positive sites revealed significantly higher occurrence of co-infections by P. gingivalis, B. forsythus, S. sputigena or by P. gingivalis, B. forsythus, S. intermedius than AST negative sites (p<0.001). P. gingivalis, B. forsythus, A. naeslundii co-infection was found significantly higher in the AST negative sites (p<0.001). CONCLUSIONS: The present study found a high level of agreement between the presence of putative periodontal pathogens and positive AST scores at periodontal sites that clinically were considered to be potentially disease active. Prospective studies should be performed to confirm the findings.

Adult↗