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PubMed1984

Return of Streptococcus faecalis DNA cloned in Escherichia coli to its original host via transformation of Streptococcus sanguis followed by conjugative mobilization.

Cloning vectors were introduced into Streptococcus faecalis by conjugation. A conjugative plasmid (pVA797) and cloning vector pVA838 recombined in Streptococcus sanguis at homologous sequences, forming a cointegrate. The pVA797::pVA838 cointegrate transferred to S. faecalis by conjugation. Recombination between homologous sequences resolved the cointegrate in the S. faecalis transconjugants, and pVA797 and pVA838 segregated because of incompatibility. S. faecalis strains that received pVA838 by this mechanism contained plasmids indistinguishable from authentic pVA838 from Escherichia coli. Other plasmids, including pVA736, were introduced into S. faecalis by this method. This approach should facilitate the introduction of cloned DNA into S. faecalis.

Cloning, Molecular↗
PubMed2002

[The inhibitory effect of anti-streptococcus mutans immunoglobulin of yolk on glucan synthesis of Streptococcus mutans].

OBJECTIVES: To observe the inhibitory effect of anti-Streptococcus mutans Hen-egg-yolk (IgY) on glucan synthesis of Streptococcus mutans. METHODS: Determine the glucan with anthrone method after using the different titer of IgY on S.mutans and S.sobrinus. RESULTS: The inhibitory effect of antibody on S.mutans and S.sobrinus synthesis glucan had a similar tendency. The effect of inhibit glucan synthesis was influenced by the titer of antibody. High titer with high inhibition. Begin with the group of 1:16 titer, the group of 1:2 titer showed the highest inhibition (P<0.05). CONCLUSION: The antibody can reduce synthesis of glucan from S.mutans and S.sobrinus.

English Abstract↗
PubMed1984

Expression of a streptokinase gene from Streptococcus equisimilis in Streptococcus sanguis.

Using recombinant DNA techniques, we introduced a previously cloned streptokinase gene from Streptococcus equisimilis into the Challis strain of S. sanguis (group H). The gene was expressed in the new host under the control of its own promoter and the gene product had biological properties identical to authentic streptokinase. However, the molecular weight of cloned streptokinase (42 K) as expressed by S. sanguis was substantially lower than that of authentic streptokinase (47 K). Since the cloned streptokinase gene encoded a 47 K mature protein, the lowered molecular weight of S. sanguis streptokinase may reflect posttranslational proteolytic cleavage, which leaves the biological activity of the gene product and its serological reactivity unimpaired.

Cloning, Molecular↗
PubMed1991

Inhibition of the growth of Streptococcus mutans, Streptococcus sobrinus and Lactobacillus casei by oral peroxidase systems in human saliva.

Streptococcus mutans, Strep. sobrinus and Lactobacillus casei were grown in glucose-supplemented, sterilized, human whole saliva, adjusted to pH 5, 6 or 7. Components of the antibacterial peroxidase system--hypothiocyanous acid (HOSCN) and hypothiocyanite ions (OSCN-)--were generated by adding exogenous H2O2 to sterilized saliva containing endogenous peroxidases and thiocyanate (SCN-) ions. HOSCN/OSCN- generation was proportional to the amount of H2O2 added, and more HOSCN/OSCN- was detected in saliva at pH 7 than at pH 5. However, the growth of mutans streptococci and L. casei was inhibited at pH 5 by HOSCN/OSCN-, whereas no inhibition was found at pH 7. The findings show that (a) sufficient amount of HOSCN/OSCN- will inhibit the growth of cariogenic bacteria in human saliva at pH 5; (b) this amount of HOSCN/OSCN- can be generated in saliva by exogenously added H2O2; and (c) peroxidase systems have stronger antistreptococcal effects in human whole saliva than in phosphate buffer.

Anti-Bacterial Agents↗
PubMed1995

Streptococcus oralis previously identified as uncommon 'Streptococcus sanguis' in Behçet's disease.

The relation between the biochemical and serological properties of 'Streptococcus sanguis' was studied to characterize the strains isolated from dental plaque of patients with Behçet's disease and controls. Seven reference and 100 clinical strains preserved by the Behçet's Disease Research Committee of Japan were identified using established criteria and differentiated with antisera against Strep. oralis ATCC 10557, Strep. sanguis ATCC 10556 and 'Strep. sanguis' ST7, compatible with the criteria. Uncommon serovars (serotypes) KTH-1 (= ATCC 49298), KTH-2 (= ATCC 49296), KTH-3 (= ATCC KTH-4 (= ATCC 49297) and B220 (serovar KTH-1) with both IgA1 protease and neuraminidase (sialidase) were identified as Strep. oralis, whereas common serovars ST3 with IgA1 protease alone and ST7 without both enzymes were identified as Strep. sanguis and Strep. gordonii, respectively. Isolates previously ranked as uncommon serovars were identified as Strep. oralis, whereas the rest ranked as common serovars were identified as the same species as those of the grouping strains. A soft-agar technique was available for species identification except for Strep. oralis serovar KTH-1 reacting with the antiserum against Strep. gordonii ST7. The frequency of isolation of Strep. oralis was higher in Behçet's disease (52%) than in controls (38%), but no difference was observed between the properties of the two groups of isolates. Strep. oralis virulence factors may be involved in breach the mucosal barrier in patients with specific reactivity to these antigens and inducing Behçet's disease.

Behcet Syndrome↗
PubMed1995

Immunoblot analysis of bacterial polysaccharides: application to the type-specific polysaccharides of Streptococcus suis and Streptococcus agalactiae.

A method for the immunoblot analysis of the type-specific capsular polysaccharides of streptococci was developed. The capsular polysaccharides were extracted by sonication and subjected to polyacrylamide gel electrophoresis in the absence of sodium dodecyl sulphate (SDS). After electrophoresis the polysaccharides were transferred to charged PVDF-N membranes and probed with the type specific antibodies. A characteristic ladder-like pattern of polysaccharide bands specific for the serotype (1, 2, 4, 7) was observed for capsular extracts of Streptococcus suis. Human immune sera against type-specific group B streptococcal polysaccharides reacted most strongly with the immunizing polysaccharide type (Ia, II, III). The previously observed crossreactions between the group B streptococcal type-specific capsular preparations were shown to be due to binding to the isomeric polysaccharide molecules. Thus, gel electrophoresis combined with immunoblot analysis seems to provide a novel method for the molecular and immunochemical characterization of bacterial polysaccharides and for the study of the specificity and properties of antibodies to capsular polysaccharides.

Animals↗
PubMed2006

The ltp gene of temperate Streptococcus thermophilus phage TP-J34 confers superinfection exclusion to Streptococcus thermophilus and Lactococcus lactis.

The ltp gene, located within the lysogeny module of temperate Streptococcus thermophilus phage TP-J34, has been shown to be expressed in lysogenic strain S. thermophilus J34. It codes for a lipoprotein, as demonstrated by inhibition of cleavage of the signal sequence by globomycin. Exposure of Ltp on the surface of Lactococcus lactis protoplasts bearing a plasmid-encoded copy of ltp has been demonstrated by immunogold labeling and electron microscopy. Expression of ltp in prophage- and plasmid-cured S. thermophilus J34-6f interfered with TP-J34 infection. While plating efficiency was reduced by a factor of about 40 and lysis of strain J34-6f in liquid medium was delayed considerably, phage adsorption was not affected at all. Intracellular accumulation of phage DNA was shown to be inhibited by Ltp. This indicates interference of Ltp with infection at the stage of triggering DNA release and injection into the cell, indicating a role of Ltp in superinfection exclusion. Expression of ltp in L. lactis Bu2-60 showed that the same superinfection exclusion mechanism was strongly effective against phage P008, a member of the lactococcal 936 phage species: no plaque-formation was detectable with even 10(9) phage per ml applied, and lysis in liquid medium did not occur. In Lactococcus also, Ltp apparently inhibited phage DNA release and/or injection. Ltp appears to be a member of a family of small, secreted proteins with a 42 amino acids repeat structure encoded by genes of Gram-positive bacteria. Some of these homologous genes are part of the genomes of prophages.

Amino Acid Sequence↗
PubMed2002

Simultaneous measurement of the viability, aggregation, and live and dead adherence of Streptococcus crista, Streptococcus mutans and Actinobacillus actinomycetemcomitans in human saliva in relation to indices of caries, dental plaque and periodontal disease.

Salivary proteins have multiple functions and many share similar functions, which may be why it has been difficult to relate variations in their concentrations to oral health and ecology. An alternative is to focus on variations in the major functions of saliva. An hydroxyapatite-coated microplate model has been developed that simultaneously measures saliva-promoted bacterial viability, bacterial aggregation, and live and dead bacterial adherence, while simulating oral temperature and shearing forces from swallowing. That model was applied to resting whole and stimulated parotid saliva from 149 individuals, using representative strains of Streptococcus crista, S. mutans, and Actinobacillus actinomycetemcomitans. Two major factors were defined by multivariate analysis (this was successful only for whole-saliva). One factor was correlated with aggregation, live adherence and dead adherence for all three strains; the other was correlated with total viability of all three strains. Participants were grouped <25th percentile and >75th percentile for each factor. Those groups were compared for clinical indices of oral health. Caries scores were significantly lower in those with high scores for aggregation-adherence, regardless of whether total viability scores were low or high. Live bacteria always predominated on surfaces when live and dead adherence scores were expressed as ratios. However, participants with high scores for aggregation-adherence showed significantly more dead adherent bacteria than those with low scores (these ratios were uncorrelated with total viability). This finding may indicate that extreme differences in the ability to kill bacteria on surfaces can influence caries risk.

Adult↗
PubMed1996

Saliva mediated adherence, aggregation and prevalence in dental plaque of Streptococcus mutans, Streptococcus sanguis and Actinomyces spp, in young and elderly humans.

Salivary components in the pellicle mediate bacterial adherence to the tooth. Such components may also aggregate bacteria in saliva and prevent them becoming established in dental plaque. In the present study, the adherence and aggregation of Streptococcus mutans strain Ingbritt, S. sanguis strain 10556 and Actinomyces viscosus-strain 19246 mediated by parotid and whole saliva from groups of young and elderly people were examined. Significant differences were found between test strains, salivary secretions and age groups. S. sanguis 10556 and A. viscosus 19246 generally adhered more strongly than S. mutans Ingbritt, which adhered better to pellicles from parotid saliva than from whole saliva Strain 19246 bound in higher numbers to parotid saliva pellicles from elderly compared to young individuals. Strain 10556 adhered better to whole saliva than parotid saliva pellicles, and the difference was significant among the young individuals, indicating reduced adherence ability in elderly whole saliva. The streptococci were aggregated by parotid and whole saliva, and S. sanguis aggregation was less with whole saliva from the elderly than from the young participants. Besides a correlation between whole saliva aggregation of S. mutans and proportions of bacteria in plaque, no correlations were found for the individual binding properties of saliva and prevalence of bacteria in vivo. However, the level of saliva-mediated adherence in vitro was in the following order: S. mutans. Actinomyces S sanguis, which corresponded to their isolation frequency in plaque. These findings emphasize the importance of initial adherence to salivary receptors in bacterial colonization on teeth. Further studies are needed to reveal if individual patterns in the in vitro binding characteristics of saliva lead to variation of colonization in vivo.

Actinomyces viscosus↗
PubMed2000

Macrolide resistance and erythromycin resistance determinants among Belgian Streptococcus pyogenes and Streptococcus pneumoniae isolates.

Resistance of streptococci to macrolide antibiotics is caused by target-site modification or drug efflux. The phenotypic expression of target-site modification can be inducible or constitutive. The prevalence of the three phenotypes among Belgian erythromycin-resistant Group A streptococci (GAS) and Streptococcus pneumoniae isolates was surveyed, their MICs for seven antibiotics were determined and the clonality of the isolates was explored. Of the 2014 GAS isolates tested 131(6.5%) were erythromycin resistant (MIC > 1 mg/L): 110 (84.0%) showed the M-resistance phenotype whereas the remaining 21 strains (16.0%) were constitutively resistant. No inducibly resistant strains were detected. Of 100 S. pneumoniae isolates, 33 were erythromycin resistant (MIC > 1 mg/L). In contrast to the GAS isolates, only 9.1% of the 33 erythromycin-resistant S. pneumoniae isolates showed the M-resistance phenotype. The presence of mefA/E and ermB genes in the M-resistant and constitutively and inducibly resistant strains, respectively, was confirmed by PCR analysis. Genomic analysis based on pulsed-field gel electrophoresis (PFGE) using the restriction enzyme SfiI, revealed 54 different PFGE patterns among the 131 erythromycin-resistant GAS isolates, of which an M6 clone represented 16.0% of the strains; all other clones, exhibiting different M-types, represented <7% of the strains. The S. pneumoniae isolates also appeared to be polyclonally based, as determined by arbitrarily primed PCR. The macrolides miocamycin and rovamycin, the lincosamide clindamycin and the ketolide HMR 3647 showed excellent activity against the M-resistant GAS and S. pneumoniae strains.

Anti-Bacterial Agents↗
PubMed2000

Impact of azithromycin on oropharyngeal carriage of group A Streptococcus and nasopharyngeal carriage of macrolide-resistant Streptococcus pneumoniae.

BACKGROUND: Invasive group A streptococcal (GAS) infections are a cause of serious morbidity and high mortality. There is a need for a simple, effective antimicrobial regimen that could be used to prevent invasive GAS disease in high risk situations. To assess azithromycin as a chemoprophylactic agent, we evaluated its efficacy for eradication of oropharyngeal (OP) GAS and its impact on the nasopharyngeal (NP) colonization rate of macrolide-resistant Streptococcus pneumoniae. METHODS: We obtained OP and NP swabs for GAS and pneumococcus culture, respectively, from 300 schoolmates of a child with an invasive GAS infection. GAS culture-positive students were treated with daily azithromycin (12 mg/kg/day) for 5 days. We obtained follow-up OP and NP swabs at 9 (Day 17) and 24 (Day 32) days post-treatment from those students identified as GAS carriers on Day 0 and determined macrolide susceptibility of GAS and pneumococcal isolates. RESULTS: Of the 300 students swabbed 152 (50%) carried GAS in their oropharynx. On Day 17, efficacy of azithromycin for GAS eradication was 95% (140 of 147) for all students. NP colonization rates for pneumococci decreased from 46% (67 of 146) to 12% (17 of 144; P < 0.001) by Day 17 and to 20% (27 of 137; P < 0.001) by Day 32. The prevalence of erythromycin-resistant pneumococcal isolates increased from 2% (3 of 146) to 4% (6 of 144) by Day 17 and to 8% (11 of 137; P = 0.04) by Day 32. CONCLUSIONS: Azithromycin is an effective short course regimen for eradication of oropharyngeal GAS. However, azithromycin selected for macrolide-resistant strains of pneumococci. These findings highlight the importance of determining the appropriate circumstances for antimicrobial prophylaxis to prevent invasive GAS infections.

Anti-Bacterial Agents↗
PubMed1983

Protoplast and cytoplasmic membrane preparations from Streptococcus sanguis and Streptococcus mutans.

Protoplasts were prepared from Streptococcus sanguis and some S. mutans serotypes by use of lysozyme (EC 3.2.1.17) under particular conditions: cells had to be grown in DL-threonine (20 mM) and harvested in early exponential phase. The efficiency of protoplast formation was enhanced by two additional steps: plasmolysis (in 12% PEG), prior to addition of lysozyme, and a swirling phase, after the enzymic action. This procedure allowed us to obtain clean protoplasts, with only 0.5% contamination by bacterial cell walls. Up to 90% protoplast lysis was obtained in 0.5 M-NaCl. Cytoplasmic membrane purification was achieved by centrifugation on a glycerol cushion.

Bacteriological Techniques↗
PubMed2001

Effect of hydrolysable and condensed tannins on growth, morphology and metabolism of Streptococcus gallolyticus (S. caprinus) and Streptococcus bovis.

Streptococcus gallolyticus (S. caprinus) was resistant in vitro to at least 7% (w/v) tannic acid and 4% (w/v) acacia condensed tannin, levels 10-fold greater than those tolerated by S. bovis. Growth of S. gallolyticus in liquid medium was characterized by a lag period which increased, and a growth rate which decreased, with increasing tannin concentration. S. gallolyticus was also more tolerant to the presence of simple phenolic acid monomers than was S. bovis, but the lag period was still concentration dependent. Gallate decarboxylase activity in S. gallolyticus was elevated in the presence of tannic acid or gallic acid but not with other phenolic acids. Scanning electron microscopic analysis showed that both the size and shape of S. gallolyticus and S. bovis changed in response to tannin but only S. gallolyticus was surrounded by an extracellular polysaccharide matrix which accumulated in a tannin-concentration-dependent fashion. Washing of the cells to remove extracellular polysaccharide increased the lag period of S. gallolyticus in the presence of 1% (w/v) tannic acid from 4 h to 6 h. In contrast, increasing extracellular polysaccharide synthesis in S. bovis did not increase its tolerance to tannic acid. These data demonstrate that S. gallolyticus has developed a number of mechanisms to reduce the potential effect of tannins on cell growth, and that these mechanisms provide the organism with a selective advantage over S. bovis when grown in the presence of tannins.

Carboxy-Lyases↗
PubMed2004

Frequent and preferential infection of Treponema denticola, Streptococcus mitis, and Streptococcus anginosus in esophageal cancers.

Multiple cancers frequently occur in the upper digestive tract. One possible explanation is that specific bacterial infection stimulates the normal epithelium to initiate inflammation and/or promotes carcinogenesis. This study was undertaken to determine which bacterial species is predominantly associated with esophageal cancer. We examined the bacterial diversity in this type of cancer and in the saliva from healthy people by using a culture-independent molecular method. Here we report the preferential and frequent infection of the oral periodontopathic spirochete Treponema denticola (T. denticola), Streptococcus mitis (S. mitis), and Streptococus anginosus (S. anginosus) in esophageal cancer from different regions of the world, and we also describe the induction of inflammatory cytokines by infection of S. anginosus and S. mitis. Our present data suggest that these three bacteria could have significant roles in the carcinogenic process of many cases of esophageal cancer by causing inflammation and by promoting the carcinogenic process, and that eradication of these three bacteria may decrease the risk of recurrence.

Blotting, Northern↗
PubMed2001

Antimicrobial susceptibilities of 1,684 Streptococcus pneumoniae and 2,039 Streptococcus pyogenes isolates and their ecological relationships: results of a 1-year (1998-1999) multicenter surveillance study in Spain.

A nationwide multicenter susceptibility surveillance study which included 1,684 Streptococcus pneumoniae and 2,039 S. pyogenes isolates was carried out over 1 year in order to assess the current resistance patterns for the two most important gram-positive microorganisms responsible for community-acquired infections in Spain. Susceptibility testing was done by a broth microdilution method according to National Committee for Clinical Laboratory Standards M100-S10 interpretative criteria. For S. pneumoniae, the prevalences of highly resistant strains were 5% for amoxicillin and amoxicillin-clavulanic acid; 7% for cefotaxime; 22% for penicillin; 31% for cefuroxime; 35% for erythromycin, clarithromycin, and azithromycin; and 42% for cefaclor. For S. pyogenes, the prevalence of erythromycin resistance was 20%. Efflux was encountered in 90% of S. pyogenes and 5% of S. pneumoniae isolates that exhibited erythromycin resistance. Erythromycin resistance was associated with clarithromycin and azithromycin in both species, regardless of phenotype. Despite the different nature of the mechanisms of resistance, a positive correlation (r = 0.612) between the two species in the prevalence of erythromycin resistance was found in site-by-site comparisons, suggesting some kind of link with antibiotic consumption. Regarding ciprofloxacin, the MIC was >or=4 microg/ml for 7% of S. pneumoniae and 3.5% of S. pyogenes isolates. Ciprofloxacin resistance (MIC, >or=4 microg/ml) was significantly (P < 0.05) associated with macrolide resistance in both S. pyogenes and S. pneumoniae and with penicillin nonsusceptibility in S. pneumoniae.

Drug Prescriptions↗
PubMed2005

Distribution of subclasses mefA and mefE of the mefA gene among clinical isolates of macrolide-resistant (M-phenotype) Streptococcus pneumoniae, viridans group streptococci, and Streptococcus pyogenes.

The distribution of subclasses mefA and mefE of the mefA gene among 116 M-phenotype streptococci was as follows: pneumococci (38 strains had mefE and 4 mefA), viridans streptococci (49 mefE and 1 mefA), and Streptococcus pyogenes (24 mefA). Spain(9V)-3-14 and England(14)-9 clones of serotype 14 were dominant among pneumococci.

Anti-Bacterial Agents↗
PubMed1978

Specificity of salivary-bacterial interactions: role of terminal sialic acid residues in the interaction of salivary glycoproteins with Streptococcus sanguis and Streptococcus mutans.

Four highly purified salivary glycoproteins were used to study salivary-bacterial interactions. One pair of glycoproteins was mucin-like in composition, whereas the second pair was not. By an agglutination assay, it was found that only the mucin-glycoproteins agglutinated Streptococcus sanguis and S. mutans. Removal of sialic acid from these molecules resulted in a loss of agglutination of S. sanguis but not of S. mutans. The agglutination phenomenon was shown to require a salivary macromolecule of at least 150,000 daltons.

Agglutination↗
PubMed1978

Isolation and characterization of a Streptococcus mutans bacteriocin inhibitor from Streptococcus pyogenes.

An inhibitor of Streptococcus mutans strain GS5 bacteriocin was released from a bacteriocin-sensitive strain of S. pyogenes by sonic treatment and partly purified by gel filtration on a Sepharose 6B column. The inhibitory factor was sensitive to heat, trypsin, and periodate and possessed a molecular weight of approximately 93,000. This factor may be the receptor for the S. mutans bacteriocin.

Bacterial Proteins↗