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PubMed1981

Common antigens of streptococcal and non-streptococcal oral bacteria: immunochemical studies of extracellular and cell-wall-associated antigens from Streptococcus sanguis, Streptococcus mutans, Lactobacillus salivarius, and Actinomyces viscosus.

Soluble extracellular antigens (ESA) were prepared from the culture supernatant of exponential growing cells of Streptococcus sanguis OMZ 9 by a combination of ammonium sulfate precipitation and chromatography on a Bio-Gel P6 column. Soluble cell wall antigens (WEA) were obtained from the bacterial pellet by extraction with 1 M phosphate buffer (pH 6). Antisera against whole cells of S. sanguis and S. mutans of different serotypes, 10% trichloroacetic extracts of bacterial cell walls, dextran, ESA, and WEA were prepared by injecting the different antigens several times in rabbits. ESA and WEA were prepared from a representative strain of Bratthall's seven serological groups, Lactobacillus salivarius, and Actinomyces viscosus. All sera showed various agglutinin titers against heat-killed cells, and titers were generally higher with homologous cells. The comparison of the different antigens using agar gel diffusion and immunoelectrophoresis showed the presence of extracellular common antigens in both ESA and WEA between the different strains. Absorption of anti-ESA sera with WEA, and anti-WEA sera with ESA, showed the existence of a specific antigen common to all bacteria in each fraction. Enzymatic treatment of the antigen before immunodiffusion demonstrated the protein nature of the two antigens present in ESA and WEA.

Actinomyces↗
PubMed1982

Influence of sodium and potassium ions on acid production by washed cells of Streptococcus mutans ingbritt and Streptococcus sanguis NCTC 7865 grown in a chemostat.

A comparison was made of acid production by cells of Streptococcus mutans Ingbritt and S. sanguis NCTC 7865 that had been washed twice and incubated in different concentrations of sodium and potassium ions. Organisms were grown under defined conditions in a chemostat under both glucose limitation and glucose excess conditions at a dilution rate of 0.1 h(-1) (mean generation time, 6.9 h). Acid production after a pulse of glucose, sucrose, and fructose was measured by pH fall experiments and as a rate at pH 7.0. S. mutans produced more acid than S. sanguis as measured by either criterion, although statistically faster rates of acid production and lower terminal pH values were obtained when cells of both species were suspended in KCl rather than in NaCl, with 200 mM KCl resulting in the lowest terminal pH in pH fall experiments. Sodium ions inhibited acid production: 183 mM NaCl reduced the glycolytic rates of S. mutans and S. sanguis metabolizing glucose at pH 7.0 in 135 mM KCl by 39 and 33%, respectively. The most pronounced stimulatory effect of potassium on acid production was by washed cells of S. sanguis that had been grown under arginine and under phosphate limitation. The pH fell by a further 0.86 and 1.21 pH units, respectively, and to below the critical pH for enamel demineralization when these cells were metabolizing glucose in 135 mM KCl compared with the same concentration of NaCl. This enhancement of acid production was not due to potassium translocation, as had been suggested previously, because no movement of potassium ions across the cell membrane could be detected. An alternative explanation is proposed in which sodium ions are excluded from the cell at the expense of membrane energy, i.e., the proton motive force, which could otherwise be used for the transport of sugars.

Fructose↗
PubMed1989

Fibrinogen binding and resistance to phagocytosis of Streptococcus sanguis expressing cloned M protein of Streptococcus pyogenes.

The biological properties of Streptococcus pyogenes M protein cloned and expressed in S. sanguis were investigated. The spm-5 gene previously cloned into Escherichia coli was subcloned into the E. coli-S. sanguis shuttle plasmid pVA838 to produce a newly constructed plasmid, pBK100. Cells of S. sanguis transformed with pBK100 expressed 53-, 55-, and 58-kilodalton polypeptides reacting with type 5 M protein antiserum in immunoblots. The M protein was expressed on the surface of S. sanguis cells as shown by the capacity of the intact cells to (i) inhibit the reactivity of anti-type 5 antibodies with purified M protein as demonstrated by enzyme-linked immunosorbent assay; (ii) inhibit the opsonization by M5 antisera of type 5 S. pyogenes; (iii) express M-protein-like fibrils on the surface of the organisms that react with M5 antisera as revealed by immunoelectron microscopy; (iv) bind plasma fibrinogen and, as a consequence, resist phagocytosis by human blood neutrophils; and (v) be rendered susceptible to phagocytosis by opsonic M5 antisera. These results provide additional evidence that streptococcal M proteins bind host proteins as a ploy to evade host defense mechanisms.

Antigens, Bacterial↗
PubMed2005

Clinical and microbiological responses of volunteers to combined intranasal and oral inoculation with a Streptococcus gordonii carrier strain intended for future use as a group A streptococcus vaccine.

Streptococcus gordonii shows promise as a live mucosal vaccine vector for immunization against respiratory pathogens. In preparation for clinical trials to evaluate S. gordonii engineered to express group A streptococcal M protein antigens, we characterized the responses of 150 healthy volunteers to combined nasal and oral inoculation with approximately 1.5 x 10(9) CFU of SP204(1-1), an S. gordonii strain not bearing vaccine antigens. SP204(1-1) was selected for resistance to streptomycin and 5-fluoro-2-deoxyuridine to distinguish it from indigenous flora. In two antibiotic treatment studies, we performed serial culturing of nose, mouth, and saliva samples from 120 subjects treated with azithromycin beginning 5 days after inoculation to determine whether SP204(1-1) could be rapidly eliminated should safety concerns arise. A natural history study was performed to assess the time until spontaneous eradication in the remaining 30 subjects, who did not receive the antibiotic and who were monitored with repeated culturing for 14 weeks after inoculation. SP204(1-1) was generally well tolerated. Symptoms reported most often within 5 days of inoculation were nasal congestion (36%), headache (30%), and sore throat (19%). The strain was detected by culturing in 98% of subjects. A single dose of azithromycin eliminated colonization in 95% of subjects; all subjects receiving a 5-day course of an antibiotic showed clearance by day 11. Without the antibiotic, 82% of subjects showed spontaneous eradication of the implanted strain within 7 days, and all showed clearance by 35 days. The results of these clinical trials provide encouragement that the use of S. gordonii as a live mucosal vaccine vector is a feasible strategy.

Administration, Intranasal↗
PubMed1992

Nucleotide sequences of genes encoding penicillin-binding proteins from Streptococcus pneumoniae and Streptococcus oralis with high homology to Escherichia coli penicillin-binding proteins 1a and 1b.

The nucleotide sequence of a 3,378-bp DNA fragment of Streptococcus pneumoniae that included the structural gene for penicillin-binding protein (PBP) 1a (ponA), which encodes 719 amino acids, was determined. Homologous DNA fragments from an S. oralis strain were amplified with ponA-specific oligonucleotides. The 2,524-bp S. oralis sequence contained the coding region for the first 636 amino acids of a PBP. The coding sequence differed by 437 nucleotides (27%) and one additional triplet, resulting in 87 amino acid substitutions (14%), from S. pneumoniae PBP 1a. Both PBPs are highly homologous to bifunctional high-M(r) Escherichia coli PBPs 1a and 1b.

Amino Acid Sequence↗
PubMed1998

Ecological study of Streptococcus mutans, Streptococcus sobrinus and Lactobacillus spp. at sub-sites from approximal dental plaque from children.

Previous immunofluorescence (IF) studies have indicated that Streptococcus mutans may preferentially colonise specific sub-sites within approximal plaque. The present study aimed to extend these observations to other mutans streptococci and lactobacilli in such gingival margin plaque. Two hundred and seventy approximal plaque samples were taken from 90 teeth (3 from each tooth) in 64 children; three gingival margin sub-sites in relation to the contact area: away from (A), to the side of(S) and below (B) the contact area. Samples were processed by indirect IF using high-titred polyclonal anti-S. mutans 'c', anti-S. sobrinus 'd', anti-L. casei and anti-L. acidophilus antisera. An overall positive association was found between S. mutans 'c' and S. sobrinus 'd' (p < 0.001). Significant differences (p < 0.1) were found between the proportional counts at each sub-site for S. mutans 'c': A = 39%, S = 51% and B = 70%, and for S. sobrinus 'd' 21, 33 and 49%. Mutans streptococci (MS) appeared to preferentially colonise the sub-site below the contact area (B = 81%), compared with sub-sites A and S (48 and 62%, respectively). S. mutans 'c' and S. sobrinus 'd' were detected together at subsites A = 12%, S = 22%, and B = 38%, with proportional counts at B sites being higher than those at A (B > A, p < 0.01, and B > S, p < 0.05). Lactobacillus spp. were isolated rarely, and were usually found together with MS. There was a positive relationship between the presence of lactobacilli or MS and caries (white spot lesions only), although these species could frequently be isolated from noncarious sites. The presence of both S. mutans 'c' and S. sobrinus 'd' were strongly correlated with early caries lesions. In addition, this study confirmed the variation in the microflora at different sub-sites within approximal dental plaque.

Antibodies, Bacterial↗
PubMedDate not supplied

Genotype and phenotype relationship in MLSb resistance in Streptococcus pyogenes and Streptococcus agalactiae isolated in central Italy.

The aim of this work is to study a correlation between phenotype and genotype in clinical isolates of erythromycin-resistant Streptococcus spp. Among the 25 erythromycin-resistant S. pyogenes, we detected six strains with iMLSB, nine with cMLSB and two with M phenotypes. Among 14 erythromycin-resistant S. agalactiae, we detected five strains with iMLSB, seven with cMLSB and none with an M phenotype. Moreover, 8 S. pyogenes and 2 S. agalactiae showed a phenotype not matching the known ones described in literature, defining an unknown phenotype. Upon examination, the genetic profiles, erm(A), erm(B) and mef(A), of the clinical isolates did not easily correlate with a specific phenotype. Our findings highlighted that the whole matter of phenotypic diversity in macrolide-resistant S. pyogenes and S. agalactiae strains and the correlation with their genetic profiles should be submitted to a more careful analysis of phenotypic and genotypic characterization.

Anti-Bacterial Agents↗
PubMed1988

Synergistic antibacterial effects of copper and hexetidine against Streptococcus sobrinus and Streptococcus sanguis.

The aim of this study was to determine whether a combination of copper and hexetidine had a synergistic antibacterial effect against Streptococcus sobrinus OMZ 176 and S. sanguis 10556. Concentration ranges of the test agents alone and in combination were prepared by serial dilutions in microtiter trays with brain-heart infusion (BHI) broth as the bacterial growth medium. After incubation at 37 degrees C for 24 h, the minimum inhibitory concentration (MIC), corresponding to the lowest concentration showing no visible growth, was determined. Evaluated by the fractional inhibitory concentration index, a strong synergistic effect ranging from 0.39 to 0.40 was observed. A similar effect was also demonstrated by growth curves, which were constructed on the basis of growth in BHI broth with addition of MIC/4 of each agent alone or MIC/8 of each agent in combination. A probable explanation for these findings is that the surface-active hexetidine molecule alters the bacterial cell surfaces and thereby enables an increased amount of copper to be transported into the cell.

Copper↗
PubMed1991

Effects of lysozyme-thiocyanate combinations on the viability and lactic acid production of Streptococcus mutans and Streptococcus rattus.

Effects of human lysozyme (HLZ) combined with thiocyanate (SCN-) ions on mutans streptococci, both in physiologic salivary concentrations, were studied. The bacteria were incubated for 75 min either in HLZ-supplemented sterilized human whole saliva (pH 5 and 7) or in neutral buffer in the presence or absence of HLZ (30 mg/l)-SCN- (1-5 mM) combinations. HLZ had no inhibitory effect on the viability of Streptococcus mutans, serotype c, either in saliva or in buffer, not even at pH 5, in the presence of salivary bicarbonate or in higher (up to 240 mg/l) concentrations of HLZ. In contrast, HLZ significantly decreased the viability of S. rattus in both media. HLZ also effectively blocked the lactic acid production of S. rattus but not that of S. mutans. Thiocyanate ions, which have been proposed to enhance the antimicrobial activity of lysozyme, did not affect the antibacterial activity of HLZ or HLZ-HCO3- combinations. It is concluded that the in vivo levels of SCN- ions, which constitute an integral part of the peroxidase antimicrobial system in saliva, may not be high enough to trigger the lysis of S. mutans by lysozyme in human saliva. The very low prevalence of S. rattus compared with S. mutans in human populations may be associated with their different susceptibility to lysozyme-mediated inhibition in saliva.

Buffers↗
PubMed1993

Xylitol and the bactericidal effect of chlorhexidine and fluoride on Streptococcus mutans and Streptococcus sanguis.

The present study was made to investigate the effect of xylitol on the bactericidal and bacteriostatic action of chlorohexidine diacetate (CHX) and sodium fluoride (F) in ATCC strains of Streptococcus mutans and S. sanguis. Standardized bacterial cell suspensions were used in tests for bactericidal effect and for inhibition of growth and sucrose fermentation. The results showed no interference of xylitol with the antibacterial effect of CHX and F combinations. Xylitol did not show any additive effect either but appeared inert in the combinations used.

Analysis of Variance↗
PubMed2004

Antibiotic selection pressure and resistance in Streptococcus pneumoniae and Streptococcus pyogenes.

We correlated outpatient antibiotic use with prevalence of penicillin-nonsusceptible Streptococcus pneumoniae (PNSP), macrolide-resistant S. pneumoniae (MRSP), and macrolide-resistant S. pyogenes (MRGAS) in 20 countries. Total antibiotic use was correlated with PNSP (r = 0.75; p < 0.001), as was macrolide use with MRSP (r = 0.88; p < 0.001) and MRGAS (r = 0.71; p = 0.004). Streptococcal resistance is directly associated with antibiotic selection pressure on a national level.

Anti-Bacterial Agents↗
PubMed2004

Prevention of streptococcal pharyngitis by anti-Streptococcus pyogenes bacteriocin-like inhibitory substances (BLIS) produced by Streptococcus salivarius.

BACKGROUND & OBJECTIVES: Streptococcus salivarius is a numerically prominent member of the human oral microbiota that produces a variety of bacteriocin-like inhibitory substances (BLIS) having in vitro inhibitory activity against S. pyogenes. Our previous studies of S. salivarius isolates from children using a deferred antagonism BLIS production (P)-typing scheme showed that the 9 per cent of children having large populations of P-type 677 S. salivarius experienced fewer S. pyogenes acquisitions than either the 11 per cent of children having predominant P-type 226 populations or the 60 per cent of children with largely non-inhibitory (P-type 000) S. salivarius. Amongst the other BLIS P-types detected were a number of strongly-inhibitory (P-type 777) S. salivarius. In the present study the inhibitory agents produced by prototype strains of P-types 226, 677 and 777 S. salivarius are compared. METHODS: The prototype BLIS-producing S. salivarius strains SN, 20P3, and K12 were isolated from tongue swabbings. BLIS P-typing was done using standard procedures. The BLIS molecules were purified and characterized. RESULTS: S. salivarius SN (P-type 226) produces a heat-labile muramidase. S. salivarius 20P3 (P-type 677) produces the 2315 Da lantibiotic salivaricin A and S. salivarius K12 (P-type 777) produces two lantibiotics; salivaricin A2 (2368 Da) and salivaricin B (2733 Da). INTERPRETATION & CONCLUSION: The P-type 777 S. salivarius strain produced salivaricin A2 and salivaricin B. The combined production of two anti-S. pyogenes BLIS activities by this strain indicates that it could be adopted as a colonizing strain in bacterial interference trials.

Amino Acid Sequence↗
PubMed1986

[Isolation and characteristics of an antibacterial substance produced by a strain of Streptococcus sp. Thom-1606. A study of the biological activity of the metabolic products of Streptococcus sp. Thom-1606].

The data on the biological properties of the culture fluid of Streptococcus strain sp. TOM-1606 are presented. The native preparation has been shown to possess the capacity for stimulating the rate of the clearance of the peritoneal cavity of mice from Staphylococcus aureus cells, strain MT-1, rif. r., found to be insensitive to the action of the above-mentioned preparation in vitro. The crude preparation produces a transitory bacteriostatic effect on the streptococcal and staphylococcal strains under study. The preparation produces a prolonged bacteriostatic effect only on Micrococcus luteus test strain. All these data suggest that the crude preparation contains at least two active principles.

Animals↗
PubMed2000

Assessment of the interaction of human complement regulatory proteins with group A Streptococcus. Identification of a high-affinity group A Streptococcus binding site in FHL-1.

Group A Streptococcus (GAS), the most frequent bacterial cause of suppurative infections in humans, expresses on the cell surface M proteins with capacity to bind factor H, FHL-1 and C4b binding protein (C4BP). This has been interpreted as a mechanism developed by this pathogen to decrease phagocytosis by macrophages and polymorphonuclear cells. We report the analysis of the capacity to bind factor H, FHL-1 and C4BP of 69 clinical isolates from 19 different serotypes. We show that strains binding complement regulators (30/69) belong to specific M serotypes. Of these, M18 strains are relatively frequent and interact with all three complement regulators simultaneously. However, the most virulent M1 and M3 strains did not bind complement regulators in our assays. The relevance of the interaction between complement regulators and S. pyogenes was analyzed using different approaches with the conclusion that under physiological conditions only FHL-1 and C4BP bind to streptococci. We show that FHL-1 presents a higher binding affinity for S. pyogenes than factor H because it carries a hydrophobic, high-affinity, GAS binding site in addition to the heparin binding site in SCR7. Using synthetic peptides we provide evidence that the high-affinity GAS binding site in FHL-1 involves the hydrophobic tail (Ser-Phe-Thr-Leu) that distinguishes FHL-1 from factor H.

Amino Acid Sequence↗
PubMed2006

Yoghurt fermentation at elevated temperatures by strains of Streptococcus thermophilus expressing a small heat-shock protein: application of a two-plasmid system for constructing food-grade strains of Streptococcus thermophilus.

Streptococcus thermophilus S4 expressing a small heat-shock protein from the plasmid pSt04-encoded copy of shsp, is able to carry out fermentation at elevated temperature, i.e., at 50 degrees C. In yoghurt culture together with Lactobacillus delbrueckii subsp. bulgaricus, fermentation at elevated temperature results in a mild yoghurt with low post-acidification and improved stability of the starter bacteria during storage at 4 degrees C. To transfer pSt04 into commercial S. thermophilus yoghurt starter strains, a two-plasmid system was constructed. A helper plasmid providing a selectable antibiotic marker, but relying on the repA gene of pSt04, was transformed together with pSt04. After isolation of transformants, the helper plasmid was readily lost upon incubation of transformants in antibiotic-free medium, thus yielding food-grade strains carrying pSt04 only. Successful application of the system was demonstrated.

Cell Culture Techniques↗
PubMed1997

Pyogenic arthritis caused by streptococcus equisimilis (group-C streptococcus) in a patient with AIDS.

A patient with the Acquired ImmunoDeficiency Syndrome (AIDS) treated with a daily low dose of corticosteroids for chronic atopic dermatitis experienced a sudden episode of unilateral knee arthritis. Culture of the purulent synovial liquid yielded a pure culture of Streptococcus Equisimilis. A four week period of intravenous antibiotherapy combined with repeated drainages allowed a complete recovery of articular function.

AIDS-Related Opportunistic Infections↗
PubMed1987

The relationship between IgA antibodies to Streptococcus mutans antigens in human saliva and breast milk and the numbers of indigenous oral Streptococcus mutans.

The influence of indigenous Streptococcus mutans on naturally-occurring levels of IgA antibodies was studied in 42 lactating females. Breast milk, parotid and whole-saliva samples were collected and analysed by the ELISA method for IgA antibodies, reacting with antigens from Strep. mutans. All salivas and breast milk showed IgA antibody activity to five antigenic preparations from Strep. mutans and to a pool of Escherichia coli antigens. No correlation was observed between the IgA antibody level in breast milk and that in saliva. The total IgA in breast milk was, however, considerably higher than in the salivas. In subjects with active caries and subjects with high DMFS scores, there was a tendency toward lower levels of IgA antibodies in whole saliva than in subjects with low caries experience. The levels of specific IgA antibodies in saliva did not reflect the amount of indigenous Strep. mutans present in the mouth at the time of sampling.

Adult↗
PubMed1993

Characterization of allelic replacement in Streptococcus parasanguis: transformation and homologous recombination in a 'nontransformable' streptococcus.

We have obtained transformants of Streptococcus parasanguis FW213 containing allelic replacements in several chromosomal loci. Transformation occurred following electroporation with nonreplicating plasmids carrying two antibiotic-resistance-encoding genes, one of which is inserted into DNA homologous to the chromosomal target. In contrast with other streptococci, S. parasanguis FW213 is not transformed by linear DNA. Mutations in nonreplicating plasmid DNA preferentially replaced their homologues in the S. parasanguis FW213 chromosome by a double-crossover homologous recombination event, as shown by the fact that over 90% of transformants were sensitive to the vector-coded antibiotic marker. Southern blot analysis of these transformants showed that three of the five target loci had been mutated, and that the wild-type sequence had been replaced by the mutated sequence carried on the transforming plasmid. This bias toward homologous replacement rather than integration of the entire transforming plasmid DNA simplifies site-specific mutagenesis and genetic analysis of the streptococcal chromosome.

Alleles↗