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PubMed1996

Identification and characterization of a protease from Streptococcus oralis C104.

Streptococcus oralis is among the earliest colonizers of the tooth surface during plaque formation. As such, its enzymatic activities may influence ecologic succession on the tooth surface. In the current study, we use zymograms and preparative polyacrylamide gel electrophoresis to identify and purify a protease from S. oralis (sanguis) C104. Proteases from S. oralis C104 were detected in cell pellets at 133, 146 and 176 kDa as clear proteolytic bands on gelatin-substrate zymograms. Preparation of the major (146 kDa) protease were obtained by continuous-elution electrophoresis. The protease was active over the pH range of 7 to 9 with optimum activity between pH 8 and 9. Protease activity was inhibited by several serine protease inhibitors including phenylmethylsulfonyl fluoride, di-isopropyl-phosphofluoridate and aprotinin. The protease showed highest hydrolytic activity against azoalbumin and Bz-Pro-Phe-Arg-NA. Immunofluorescence studies with a polyclonal antiserum to the 146-kDa protease suggest it is present on the cell surface of S. oralis C104. Zymograms of cell pellets from other S. oralis strains as well as S. sanguis and Streptococcus mitis suggest that functionally similar proteases are elaborated by many early colonizers of the tooth surface.

Amino Acid Sequence↗

PubMedDate not supplied

[Hydrolysis of streptococcal polysaccharides by micromycete dextranases].

The effect of dextranase enzyme preparations obtained from Penicillium piscarium BIM G-102, Penicillium funiculosum, Aspergillus insuetus G-116 and Aspergillus ustus on polysaccharides synthesized by cariesogenic Streptococcus sanguis and Streptococcus mitis was being studied. According to the data obtained dextranases from P. piscarium, P. funiculosum and Asp. ustus can be considered as a promising anticarious agent.

Aspergillus↗

PubMed1992

Enzymic activity of salivary amylase when bound to the surface of oral streptococci.

The enzymatic activity of salivary amylase bound to the surface of several species of oral streptococci was determined by the production of acid from starch and by the degradation of maltotetraose to glucose in a coupled, spectrophotometric assay. Most strains able to bind amylase exhibited functional enzyme on their surface and produced acid from the products of amylolytic degradation. These strains were unable to utilise starch in the absence of salivary amylase. Two strains failed to produce acid from starch, despite the presence of functional salivary amylase, because they could not utilise maltose. Strains that could not bind salivary amylase failed to produce acid from starch. In no case was all the bound salivary amylase active, and two strains of Streptococcus mitis which bound amylase did not exhibit any enzyme activity on their cell surface. The ability to bind amylase may confer a survival advantage on oral bacteria which inhabit hosts that consume diets containing starch.

Acids↗

PubMed2002

Establishment of streptococci in the upper respiratory tract: longitudinal changes in the mouth and nasopharynx up to 2 years of age.

As part of a series of longitudinal studies on the development of the indigenous microflora of the upper respiratory tract, the establishment of streptococci in the oral cavity and nasopharynx and IgA1 protease production by the early streptococcal flora was examined in 50 healthy Caucasian infants at the ages of 2, 6, 12, 18 and 24 months. In the oral cavity, streptococci were found in all infants on every sampling occasion, Streptococcus mitis biovar 1 being the main finding in each age group. S. salivarius and S. mitis biovar 2 reached their highest prevalence during the first year of life, whereas the prevalence of S. oralis and S. sanguis showed no significant increase before 12 months of age. Salivary streptococci mainly consisted of the above-mentioned species during the follow-up period. In contrast to the oral cavity, no stable colonisation pattern was observed for viridans streptococci in the nasopharynx. S. mitis biovar 1 and S. pneumoniae, a traditional respiratory pathogen, were the principal streptococcal species among nasopharyngeal isolates. IgA1 protease production by early streptococci was common in infancy. Among the oral streptococcal microflora, S. mitis biovar 1 (especially during the first year of life) and S. oralis and S. sanguis constituted the main species responsible for this enzyme activity. In the nasopharynx, IgA1 protease was produced by S. mitis biovar 1, S. oralis and S. pneumoniae. In conclusion, streptococcal colonisation differs in these two close habitats in the upper respiratory tract.

Age Factors↗

PubMed2000

Profile of subgingival microbiota in children with mixed dentition.

A diversity of microbial species has been detected in children's oral flora at an early age. To investigate the composition of the subgingival microbiota of different groups of teeth in children with mixed dentition, 40 systemically healthy children, aged 7-8 years, randomly chosen, were examined. Subgingival plaque samples were taken from the mesiobuccal sites of 21, 41, 16 and 36 permanent teeth and 53, 73, 64 and 84 deciduous teeth. The samples were cultured for bacterial isolation anaerobically and in 10% CO2 plus air using selective and nonselective media. Forty-five different microbial species were isolated from both permanent and deciduous teeth. Streptococcus sanguis (79-70%), Streptococcus mitis (66-65%), Prevotella melaninogenica (51-57%), Eikenella corrodens (51-52%), Capnocytophaga gingivalis (46-34%), Capnocytophaga ochracea (45-45%), Actinomyces naeslundii (39-60%) and Prevotella intermedia (42-35%) were among the most frequently detected species in permanent and deciduous teeth respectively. Several suspected periodontal pathogens, such as Porphyromonas gingivalis, Prevotella loescheii, Campylobacter gracilis, Bacteroides forsythus, Campylobacter concisus, Peptostreptococcus micros and Selenomonas sputigena, albeit less frequently detected, were present in the microbiota of these children. The bacterial species Streptococcus constellatus, Peptostreptococcus micros, Pseudoramibacter alactolyticus, E. corrodens and Fusobacterium nucleatum were associated with non-bleeding permanent and deciduous teeth whereas Streptococcus intermedius, C. concisus, P. intermedia and P. loescheii were associated with bleeding.

Actinomyces↗

PubMed1993

Emergence of immune competence in saliva.

Saliva contains essentially no IgA at birth. However, secretory immune responses to oral and non-oral microbial antigens emerge early in life. We have investigated the characteristics of these responses in salivas of infants less than 1 month through 4 years of age, using cross-sectional and longitudinal approaches. Antibody specificities (IgA, IgA1, and IgA2) were measured in ELISA and Western blot analysis to antigens of Streptococcus mitis and S. salivarius that colonize during the neonatal period. Antibodies reactive with S. sanguis and mutans streptococci, which colonize later in the infant's life, were also determined. Concurrent investigation of the oral flora of each infant was performed and related to the observed antibody specificities. The secretory nature of the immunoglobulins in these salivas was analyzed immunologically and chromatographically. The primary molecular form of salivary IgA was dimeric in all salivas tested. Both IgA subclasses were found, although a subset of infant salivas initially contained > 90% IgA1. IgM (> 1 microgram/ml) was detected in 58% of 3- to 17-week-old infants. By 2 months of age, salivas from most infants contained IgA antibody reactive with at least two S. mitis components. Many salivas also contained antibody reactive with S. salivarius components. By the end of the first year, most salivas contained IgA1 and IgA2 antibody to S. mitis antigens. Maturation of secretory responses in the second and third year was evidenced by the appearance of increased concentrations and additional specificities of salivary IgA antibodies to S. mitis antigens. Antibody to S. mitis, S. salivarius, and S. sanguis extracellular components was detected only after infection with the respective species.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1983

Immunochemical comparison of cell-wall antigens of various viridans streptococci, including strain 2A2+3 hot from recurrent oral aphthous ulceration in man.

Several studies suggest that patients with recurrent aphthous ulceration show cell-mediated and humoral immunity to antigens of Streptococcus sanguis, particularly strain 2A2+3 HOT which is said to be antigenically similar or identical to Strep. sanguis strain ATCC 10556. However, physiological classification as well as analysis of the immunologically dominant cell-wall antigens by immunoelectrophoresis and indirect immunofluorescence showed that the strain is actually a strain of Streptococcus mitis and is antigenically more like ATCC 10557 than ATCC 10556. The findings illustrate the antigenic heterogeneity of the Strep. sanguis and Strep. mitis taxons, and demonstrate the need for antigenic analysis of viridans streptococcal strains used in immunological studies of the aetiology of disease and in antiserum production. Commercial streptococcal group and antisera were also tested.

Antigens, Bacterial↗

PubMed1977

Influence of salivary components and extracellular polysaccharide synthesis from sucrose on the attachment of Streptococcus mutans 6715 to hydroxyapatite surfaces.

The adsorption of (3)H-labeled Streptococcus mutans 6715 cells to disks of hydroxyapatite (HA) was studied. The number of streptococci that adsorbed was logarithmically related to the concentration of cells available up to at least 2 x 10(8) per ml; equilibrium occurred within 45 min. Assay reliability was verified by direct scanning electron microscopic counts. Untreated HA disks exposed to buffered saline (PBS)-suspended streptococci at a concentration of 1.1 x 10(8) per ml absorbed 3.2 x 10(6) cells per cm(2); approximately 3% of the surface area was, therefore, occupied by adsorbed organisms. The presence of adsorbed salivary components on HA reduced the number of attaching S. mutans cells by half. When S. mutans cells were suspended in saliva to mimic conditions existing in the mouth, the number of streptococci adsorbing to saliva-treated HA was reduced more than 30-fold compared to untreated HA. Approximately one-half of the streptococci adsorbed to untreated or to saliva-treated HA disks could be desorbed over a 4-h period with 0.067 M phosphate buffer. S. mutans cells exposed to sucrose to permit extracellular polysaccharide synthesis before or during adsorption attached in fewer numbers to both saliva-treated and untreated HA than PBS-treated organisms. When S. mutans cells adsorbed on untreated HA were exposed to sucrose, fewer organisms could be desorbed; thus, in situ polysaccharide synthesis promoted their more firm attachment to untreated HA. However, when saliva-suspended streptococci were adsorbed to saliva-treated HA surfaces, exposure to sucrose before or subsequent to adsorption did not promote more firm attachment. Evidently, the powerful adherence-inhibiting and desorptive effects of salivary components overshadowed any promoting effects attributable to glucan synthesis from sucrose. Similarly, no differences were noted in the desorption of S. mutans cells from human teeth after exposure to sucrose, glucose, or PBS relative to a strain of Streptococcus mitis (S. mitior). Thus, no evidence was obtained to support the hypothesis that glucan synthesis from sucrose was essential for, or promoted, the attachment of S. mutans cells to HA surfaces exposed to saliva or to the smooth surfaces of human teeth.

Adsorption↗

PubMed1995

Effect of titanium on selected oral bacterial species in vitro.

Titanium granules were tested for their antibacterial effect on strains of Streptococcus sanguis, Streptococcus mitis, Actinomyces naeslundii, Haemophilus parainfluenzae, Fusobacterium spp. and Prevotella intermedia in comparison with amalgam and two of its components, copper and tin. Glass beads were used as controls. The number of viable bacteria was estimated in samples exposed to the various materials for 1, 3, 6 and 24 h, respectively, and the viable counts were related to the baseline value. Titanium showed low antibacterial effect on the species tested. Copper and amalgam showed an expressed toxicity to all species and differed significantly from titanium and glass particles. Gram positive Streptococcus spp. and A. naeslundii showed a lower susceptibility to the metals than the Gram negative species. The antibacterial effect of copper and amalgam test particles on S. sanguis and P. intermedia was significantly decreased in the presence of serum. This study showed that some metals have a toxic effect in vitro on oral bacteria, a fact that may play a role in plaque formation when these materials are used for dental restorations. Titanium did not have a similar antibacterial effect.

Actinomyces↗

PubMed1995

Degradation and fermentation of fructo-oligosaccharides by oral streptococci.

Fructo-oligosaccharides (FOS) are claimed to have a positive effect on the intestinal flora. They are being used in functional foods in Japan and Europe. This group have tested the degradation of two commercial FOS preparations by oral streptococci in order to predict the cariogenicity of these products. Both preparations could be fermented to some extent by the species of oral streptococci tested. The enzymes necessary for the degradation of FOS were inducible. Each strain showed a specific degradation pattern. All strains, particularly Streptococcus mutans rapidly produced acid, mainly lactic acid. Streptococcus mitis also produced high concentrations of acetic acid. Plaque formation by Strep. mutans was similar to the sucrose control. It is concluded that FOS are cariogenic to a similar extent as sucrose.

Acetates↗

PubMed2002

Molecular peculiarities of the lytA gene isolated from clinical pneumococcal strains that are bile insoluble.

The autolytic LytA amidase from 12 bile (deoxycholate)-insoluble streptococcal isolates (formerly classified as atypical Streptococcus pneumoniae) showing different antibiotic resistance patterns was studied. These atypical strains, which autolyze at the end of the stationary phase of growth, contain highly divergent lytA alleles (pairwise evolutionary distances of about 20%) compared to the lytA alleles of typical pneumococci. The atypical LytA amidases exhibit a peculiar deletion of two amino acids responsible for cell wall anchoring in the carboxy-terminal domain and have a reduced specific activity. These enzymes were inhibited by 1% deoxycholate but were activated by 1% Triton X-100, a detergent that could be used as an alternative diagnostic test for this kind of strain. Preparation of functional chimeric enzymes, PCR mutagenesis, and gene replacements demonstrated that the characteristic bile insolubility of these atypical strains was due to their peculiar carboxy-terminal domain and that the 2-amino-acid deletion was responsible for the inhibitory effect of deoxycholate. However, the deletion alone did not affect the specific activity of LytA. A detailed characterization of the genes encoding the 16S rRNA and SodA together with multilocus sequence typing indicated that the strains studied here are not a single clone and, although they cannot be strictly classified as typical pneumococci, they represent a quite diverse pool of organisms closely related to S. pneumoniae. The clinical importance of these findings is underlined by the role of the lytA gene in shaping the course of pneumococcal diseases. This study can also contribute to solving diagnostic problems and to understanding the evolution and pathogenic potential of species of the Streptococcus mitis group.

Alleles↗

PubMed1980

The nature of secretory agglutinins and aggregating factors. III. Secretory conglutinin-like factor SKF detects a cross-reaction between bacteria and complement component C3.

Secretory conglutinin-like factor (SKF) reacts directly with an unknown surface component of some, but not all, oral gram-positive organisms. The absorption of SKF by bacteria is EDTA-sensitive and cannot be blocked with immunoglobulins. High levels of SKF in EDTA extracts of washed salivary sediment reveal the direct in vivo reaction of SKF with oral bacteria. Mixed aggregation with alexinated erythrocytes showed the SKF corresponds to the secretory bacterial aggregating factor (SBAF) for Streptococcus mutans serotype c and also that for Streptococcus mitis. These reactions represent a cross-reaction between bacteria and complement component C3. SKF/SBAF non-mucin glycoproteins and immunoglobulins possess receptors for bacterial components while mucins are passive carriers of blood group determinants.

Agglutinins↗

PubMed1995

Identification of pioneer viridans streptococci in the oral cavity of human neonates.

Three hundred and sixty-seven strains of pioneer streptococci isolated from the mouths of 40 healthy, full-term infants during the first month of life were examined by two taxonomic schemes that incorporated biochemical and physiological characteristics, IgA1 protease production and glycosidase activities. Streptococcus mitis biovar 1 and S. oralis comprised 55.0% of the pioneer streptococci isolated from neonates. S. salivarius constituted 25.3% of the isolates, while S. anginosus, S. mitis biovar 2, S. sanguis and S. gordonii accounted collectively for 11.4%. Difficulties in identifying streptococci were encountered and 8.4% of the 367 isolates could not be assigned to a recognised species.

Bacterial Proteins↗

PubMed2000

Trovafloxacin treatment of viridans group Streptococcus experimental endocarditis.

The activity of trovafloxacin was compared with those of vancomycin and penicillin in a model of Streptococcus sanguis species group (trovafloxacin MIC, 0.125 microg/ml) and Streptococcus mitis species group (trovafloxacin MIC, 0.125 microg/ml) experimental endocarditis. Rabbits with catheter-induced aortic valve vegetations were given no treatment, trovafloxacin at 15 mg/kg of body weight three times a day (t.i.d.), vancomycin at 15 mg/kg twice a day, or penicillin at 1. 2 x 10(6) IU t.i.d. After 3 days of treatment, the animals were sacrificed; cardiac valve vegetations were aseptically removed and cultured quantitatively. Penicillin was as active as vancomycin as measured by in vivo clearance of bacteria. Trovafloxacin was less active (P < 0.05) than vancomycin or penicillin against S. sanguis species group infection but had similar efficacy against S. mitis species group infection. Quinolones, despite MICs in the susceptible range, may not be active for serious infections caused by some viridans group streptococci.

Animals↗

PubMed1997

Identification and characterization of IS1381, a new insertion sequence in Streptococcus pneumoniae.

A new insertion sequence (IS1381) was identified in the genome of Streptococcus pneumoniae R6 as an 846-bp segment containing 20-bp terminal inverted repeats and flanked by 7-bp direct repeats. The three sequenced copies of this element have two overlapping open reading frame (ORF) genes named orfA and orfB. However, significant variations between individual copies were found, suggesting that inactivating mutations have occurred in an original single ORF. Accordingly, the consensus IS1381 element derived from the comparison of the three available copies should contain a single ORF sufficient to encode a basic protein of 267 amino acids which exhibited high similarity to the putative transposases of ISL2 from Lactobacillus helveticus and of IS702 from the cyanobacterium Calothrix sp. strain PCC 7601. A minimum of five to seven copies were detected by hybridization experiments in the R6 genome. In remarkable contrast with the two previously reported pneumococcal insertion sequences, several copies of IS1381 have been detected in all of the clinical isolates tested so far. Interestingly, Streptococcus oralis NCTC 11427 (type strain), a close relative of pneumococcus, does not contain this element, but its occurrence in the type strain of Streptococcus mitis (NCTC 12261) suggests that this species has exchanged DNA with S. pneumoniae directly or through an intermediate species.

Amino Acid Sequence↗

PubMedDate not supplied

[Non-groupable streptococci: identification, sensitivity to antibiotics (Charles Nicolle Hospital in Tunis)].

50 strains of viridans streptococci isolated from human material are identified by biochemical tests (bile esculin, Cl Na 6,5%, acid production from lactose, mannitol, sorbitol, inulin, arginine, esculin and starch hydrolysis; production of levan and dextran in sucrose media) Streptococcus salivarius and Streptococcus mitis are predominant species. Susceptibility to antibiotics was studied: 70% of viridans streptococci were susceptible to all antibiotics tested, high level resistance to aminoglycoside was not present. The only resistance observed were to tetracycline, macrolides and related drugs.

Aminoglycosides↗

PubMed1975

Bactericidal activity of combinations of penicillin or clindamycin with gentamicin or streptomycin against species of viridans streptococci.

Checkerboard bactericidal studies were performed with two strains each of Streptococcus mitis, S. salivarius, and S. sanguis, and the results were analyzed by the use of isobolograms. Synergy between penicillin and streptomycin or gentamicin was demonstrated with four strains, representing two of S. salivarius, one of S. sanguis, and one of S. mitis; the remainder were either too susceptible or too resistant to be analyzed. Clindamycin with streptomycin or gentamicin acted synergistically with three strains, representing two of S. sanguis and one of S. salivarius; the remainder were either too susceptible or too resistant to be analyzed.

Clindamycin↗

PubMed1998

Fluoroquinolone resistance mutations in the parC, parE, and gyrA genes of clinical isolates of viridans group streptococci.

The nucleotide sequences of the quinolone resistance-determining regions (QRDRs) of the parC and gyrA genes from seven ciprofloxacin-resistant (Cpr) isolates of viridans group streptococci (two high-level Cpr Streptococcus oralis and five low-level Cpr Streptococcus mitis isolates) were determined and compared with those obtained from susceptible isolates. The nucleotide sequences of the QRDRs of the parE and gyrB genes from the five low-level Cpr S. mitis isolates and from the NCTC 12261 type strain were also analyzed. Four of these low-level Cpr isolates had changes affecting the subunits of DNA topoisomerase IV: three in Ser-79 (to Phe or Ile) of ParC and one in ParE at a position not previously described to be involved in quinolone resistance (Pro-424). One isolate did not show any mutation. The two high-level Cpr S. oralis isolates showed mutations affecting equivalent residue positions of ParC and GyrA, namely, Ser-79 to Phe and Ser-81 to Phe or Tyr, respectively. The parC mutations were able to transform Streptococcus pneumoniae to ciprofloxacin resistance, while the gyrA mutations transformed S. pneumoniae only when mutations in parC were present. These results suggest that DNA topoisomerase IV is a primary target of ciprofloxacin in viridans group streptococci, DNA gyrase being a secondary target.

Amino Acid Sequence↗