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PubMed1968

Activities of arginine dihydrolase and phosphatase in Streptococcus faecalis and Streptococcus faecium.

Strains of Streptococcus faecalis and S. faecium are known to produce ammonia from arginine, but only S. faecalis couples the adenosine triphosphate (ATP) produced through the arginine dihydrolase pathway to growth processes. The specific activities of the arginine dihydrolase enzymes were found to be much lower in S. faecium (0.01 to 0.10) than in S. faecalis (0.24 to 1.60). Phosphatase activities in both strains were similar (up to 0.11), but equaled or exceeded the activities of the arginine dihydrolase enzymes in S. faecium. The failure of S. faecium to show increased growth in arginine media is explained on the basis of low activities of the arginine dihydrolase enzymes coupled with sufficient phosphatase activity to negate any benefit from ATP formed.

Adenosine Triphosphatases↗

PubMed1975

Immunoelectron microscopic identification and localization of Streptococcus sanguis with peroxidase-labeled antibody: localization of Streptococcus sanguis in intact dental plaque.

Streptococcus sanguis has been localized ultrastructurally within intact dental plaque by means of an indirect technique which utilizes horseradish peroxidase-labeled antibody. The technique allows for complete diffusion of the reagents to all portions of the plaque specimens. Control procedures can be carried out on serial sections of plaque with a bacterial composition similar to that of the experimental specimen. The 30-mum-thick sections can be examined in the light microscope to localize areas specifically labeled with peroxidase prior to cutting ultra-thin sections for electron microscopy. This study demonstrated that specific bacteria can be localized within intact dental plaque. The results also indicated that S. sanguis grows in dental plaque as columnar shaped microcolonies perpendicular to the tooth surfaces. Growth appears to be by cell division rather than deposition of new cells at the surfaces. Despite their relatively good structural preservation, the cells in the deeper (older) layers of plaque appear to have lost some of their antigenic activity in comparison to the cells near the surface.

Animals↗

PubMed1978

Effects of local immunization with glucosyltransferase fractions from Streptococcus mutans on dental caries in hamsters caused by homologous and heterologous serotypes of Streptococcus mutans.

Seven serotypes of Streptococcus mutans have been identified. The biochemical, genetic, and serological characteristics of these serotypes have indicated that certain serotypes are quite similar, whereas others are quite distinct. The effect of local immunization with glucosyltransferase (GTF) enzymes from serotypes a, c, or g on infection and disease caused by homologous or heterologous cariogenic S. mutans is reported. Organisms with either similar (a and g) or different (c and g) biochemical and serological characteristics were selected for heterologous challenge. NIH white hamsters were injected four times at weekly intervals with GTF prepared by 6 M guanidine-hydrochloride elution from water-insoluble glucan of serotypes a, c, or g, which resulted in enzyme (homologous) inhibitory activity in sera and salivas. After infection of GTF-immunized and sham-immunized groups of hamsters with cariogenic S. mutans of the same serotype as the injected antigen (homologous infection) or with S. mutans of a different serotype from the injected antigen (heterologous infection), the numbers of streptomycin-labeled S. mutans, caries, and lesions were determined. Immunization with GTF preparations from each of the three serotypes resulted in statistically significant reductions in the extent of infection and disease and number of lesions caused by infections with homologous cariogenic S. mutans. Statistically significant reductions in these three parameters were also observed in groups immunized with enzyme from serotype a (strain E49) and challenged with cariogenic serotype g (strain 6715) organisms; or immunized with enzyme from serotype c (strain Ingbritt) and challenged with cariogenic serotype g (strain 6715) organisms; or immunized with enzyme from serotype g (strain 6715) and challenged with cariogenic serotype c (strain Ingbritt) organisms. These studies suggest that soluble antigen preparations containing GTF from one serotype may elicit a protective immune response against infection with cariogenic S. mutans from many or possibly all serotypes.

Animals↗

PubMed1983

Salivary immunoglobulin A antibodies and recovery from challenge of Streptococcus mutans after oral administration of Streptococcus mutans vaccine in humans.

Heat-killed Streptococcus mutans was administered orally in two periods of 1 week to six subjects in an attempt to affect the salivary immunoglobulin A (IgA) response to this bacterium. Enzyme-linked immunosorbent assays were used to detect specific IgA antibody activity, and an immunofluorescent assay was used for measurement of total IgA in parotid saliva. The salivary IgA response to S. mutans was compared with that against a noncross-reacting antigen preparation from Escherichia coli and with antibody responses in five sham-immunized subjects. No change in salivary IgA response to S. mutans was observed after oral administration of this organism. Significantly less streptomycin-resistant S. mutans could be recovered from the six test subjects than from the five controls after the first of two challenges with streptomycin-resistant microorganisms. At the day of the first challenge, a significantly higher IgA antibody response to all tested antigens was observed in the test group than in the control group. The data show that this difference was not related to the oral administration of S. mutans but rather was an occasional finding. The coincidence of a rapid elimination of the challenge strain and a high IgA antibody response to S. mutans supports the concept that salivary IgA antibodies could have a biological significance in the human defense against cariogenic microorganisms.

Administration, Oral↗

PubMed1990

Experimental model of type IV Streptococcus agalactiae (group B streptococcus) infection in mice with early development of septic arthritis.

We have established an experimental murine model to gain insight into the pathogenicity and clinical features of type IV group B streptococcus (GBS) infections. Adult CD-1 mice were challenged intravenously with 10(7) type IV GBS cells, inducing systemic invasion. Most of the animals were able to clear the infection from the blood, brain, and lungs within 2 weeks and from the spleen and liver within 1 month. However, the animals were unable to clear the microorganism from the joints and kidneys during the 60-day observation period. About 80% of the mice challenged intravenously with type IV GBS manifested early septic arthritis, which evolved from an acute exudative synovitis to permanent lesions characterized by irreversible joint damage and ankylosis. Induction of persistent septic arthritis was dependent on the number and viability of microorganisms inoculated and was unrelated to the strain of type IV GBS and the growth phase of the inoculum. Type-specific antibodies of both immunoglobulin M and G classes could be detected by agglutination and enzyme-linked immunosorbent assay from days 7 and 14, respectively; immunoglobulin G antibodies persisted for more than 40 days. Complexes of antibodies and group- and type-specific antigens were detected in mouse sera 24 h after infection and persisted up to day 22. These results were obtained an experimental model of type IV GBS chronic infection with early development of septic arthritis, which could be useful in future studies of pathogenicity and immune mechanisms involved in the host resistance to this microorganism.

Animals↗

PubMed1991

Purification and characterization of Streptococcus adjacens (nutritionally variant Streptococcus serotype II) group antigen.

Nutritionally variant streptococci (NVS) possess amphiphiles which are serologically distinct from lipoteichoic acid and which serve as group-specific antigens for NVS. The objective of this study was to purify and characterize the NVS serotype II (Streptococcus adjacens) amphiphile. Amphiphile was isolated from stationary-phase culture supernatants of NVS strain 81 (NVS serotype II). Phenol-water extracts of culture supernatants were subjected to hydrophobic interaction chromatography and gel filtration chromatography. A homogeneous preparation of amphiphile (22 mg; 8.5 x 10(6) hemagglutination units) was recovered, and its approximate molecular size (23,000 to 24,000 Da) and chemical composition were determined. Purified S. adjacens amphiphile contained phosphorus, ribitol, galactose, galactosamine, alanine, and fatty acids in molar ratios of 1.00:0.88:1.39:1.10:0.08:0.24. Since ribitol, galactose, and galactosamine were the primary carbohydrate components, the amphiphile may exist as a polyribitol phosphate with galactose and galactosamine substituents. Preliminary structural analysis demonstrated the presence of phosphodiester bonds within the amphiphile structure. Finally, the amphiphile serves as the S. adjacens group antigen.

Animals↗

PubMed1994

Cloning and nucleotide sequence analysis of psaA, the Streptococcus pneumoniae gene encoding a 37-kilodalton protein homologous to previously reported Streptococcus sp. adhesins.

Gene psaA, which encodes the Streptococcus pneumoniae 37-kDa protein, was cloned in Escherichia coli, and its complete nucleotide sequence was determined. Analysis of the sequence of the 2.4-kb cloned fragment revealed three open reading frames (ORFs). ORF2, which is 933 bp long, was identified as psaA. The two other ORFs identified flank psaA. ORF1, located upstream of psaA, is 836 nucleotides long and encodes a protein with a calculated molecular mass of 29,843 Da. The sequence for ORF3, located downstream of psaA, was only partially determined. Northern (RNA) blot analysis of pneumococcal RNA suggests that psaA is transcribed as part of a polycistronic message. Analysis of the primary structure of the protein encoded by this gene indicated significant similarity to two previously reported streptococcal proteins, SsaB (80% similarity) and FimA (92.3% similarity), from S. sanguis and S. parasanguis, respectively. These two homologous proteins have been shown to be associated with bacterial adhesion, and the possibility of a similar role for PsaA is hypothesized.

Adhesins, Bacterial↗

PubMed1973

Antigens of Streptococcus mutans. I. Characterization of a serotype-specific determinant from Streptococcus mutans.

A membrane-associated glycerol teichoic acid antigen has been isolated from Streptococcus mutans AHT and a similar antigen has been demonstrated to be present in each of the other Bratthall serotype a organisms studied. Trichloroacetic acid-extracted material was resolved into two phosphorus-containing antigenic fractions (B and C) by agarose chromatography. Fraction B was preliminarily identified as a phospholipid moiety with a glycerol-to-phosphorus ratio of 2:1, and fraction C showed a ratio of 1:1 indicative of a glycerol teichoic acid. This latter fraction also was associated with glucose, galactose, alanine, and fatty acids. Diglycerol triphosphate, the compound characteristically released from 1-3 phosphodiester-linked glycerol teichoic acids by alkaline hydrolysis, was isolated and characterized. Alanine was identified as its alkaline-labile, ester-linked D-isomer. A glyceride was isolated containing a disaccharide of glucose and galactose attached to the 2-hydroxyl group of glycerol. Hapten inhibition analysis demonstrated that beta-galactosides were the greatest inhibitors of the precipitin reaction (>75%), whereas glucose and its derivatives inhibited to a much lesser extent (<30%). Comparative immunodiffusion and immuno-electrophoresis analyses demonstrated that all six Bratthall serotype a organisms tested contained this antigenic determinant and that it was absent in serotypes b, c, and d. It is suggested that the common antigenic determinant of this serotype within S. mutans may be a beta-galactoside associated with a glycerol teichoic acid and possibly other polymers.

Amino Acids↗

PubMed2004

Proapoptotic effect of proteolytic activation of matrix metalloproteinases by Streptococcus pyogenes thiol proteinase (Streptococcus pyrogenic exotoxin B).

Streptococcus pyogenes thiol proteinase, also known as streptococcal pyrogenic exotoxin B (SpeB), has been suggested to be a major virulence factor in S. pyogenes infection. SpeB was reported to induce apoptosis of host cells, but its mechanism of action is not yet fully understood. In this study, we examined the involvement of matrix metalloproteinases (MMPs) in SpeB-induced apoptosis. We first developed a large-scale preparation of recombinant SpeB and precursors of human MMP-9 and -2 (proMMPs) by using Escherichia coli Rosetta (DE3)pLysS and baculovirus-insect cell expression systems, respectively. Treatment with SpeB induced effective proteolytic activation of both proMMP-9 and -2. When RAW264 murine macrophages were incubated with SpeB-activated proMMP-9, the level of tumor necrosis factor alpha (TNF-alpha) in conditioned medium (CM), assessed by an enzyme immunoassay, was elevated. This increase was completely inhibited by addition of the MMP inhibitor SI-27 to the cell culture. The CM also produced marked induction of apoptosis of U937 human monocytic cells. Similarly, soluble Fas ligand (sFasL) was detected in CM of cultures of SW480 cells expressing FasL after treatment with SpeB-activated proMMPs; this CM also induced apoptosis in U937 cells. SpeB had a direct effect as well and caused the release of TNF-alpha and sFasL from the cells. SpeB-dependent production of MMP-9 and -2 and proapoptotic molecules (TNF-alpha and sFasL) was evident in a murine model of severe invasive S. pyogenes infection. These results suggest that SpeB or SpeB-activated MMPs contribute to tissue damage and streptococcal invasion in the host via extracellular release of TNF-alpha and sFasL.

Animals↗

PubMed1974

Mechanism of adherence of Streptococcus mutans to smooth surfaces. II. Nature of the binding site and the adsorption of dextran-levan synthetase enzymes on the cell-wall surface of the streptococcus.

The mechanism of adsorption of the Streptococcus mutans enzymes responsible for the synthesis of insoluble dextran-levan to the S. mutans cell-wall binding sites has been studied. Certain characteristics of these binding sites are presented. The adsorption of these enzymes to the cell surface occurred rapidly without the addition of a source of energy and over a pH range of 3 to 11. The adsorption was inhibited by soluble dextran, probably due to the strong affinity of the polymer to the enzyme. All other polymers and sugars studied showed little or no inhibition. The adsorption was also inhibited by antibody globulin to the a-d immunologically specific group antigen surface polysaccharide of S. mutans and by anti-dextran globulin. The inhibition by anti-a-d globulin is considered to be due to a restriction of access of enzyme to the binding site of the enzyme which may be located in close proximity to the group antigen. On the other hand, anti-dextran globulin appeared to directly inhibit the adsorption by covering the binding site. Dextranase destroyed the binding site and released glucose from the S. mutans cells. These data indicate that S. mutans grown in media containing glucose possesses a small amount of dextran on the cell surface, and that this dextran is, or is a part of, the binding site for enzymes which synthesize the insoluble dextran-levan polymer. Trypsin inhibited the synthesis of insoluble polysaccharide and the adherence of cells. It is not clear in this case that destruction of the binding sites occurred. These data present a partial explanation of the processes which may be concerned in the formation of dental plaque on the smooth surfaces of teeth.

Adsorption↗

PubMed2006

Interference between Streptococcus pneumoniae and Staphylococcus aureus: In vitro hydrogen peroxide-mediated killing by Streptococcus pneumoniae.

The bactericidal activity of Streptococcus pneumoniae toward Staphylococcus aureus is mediated by hydrogen peroxide. Catalase eliminated this activity. Pneumococci grown anaerobically or genetically lacking pyruvate oxidase (SpxB) were not bactericidal, nor were nonpneumococcal streptococci. These results provide a possible mechanistic explanation for the interspecies interference observed in epidemiologic studies.

Antibiosis↗

PubMed1987

Control of glycolysis by glyceraldehyde-3-phosphate dehydrogenase in Streptococcus cremoris and Streptococcus lactis.

The decreased response of the energy metabolism of lactose-starved Streptococcus cremoris upon readdition of lactose is caused by a decrease of the glycolytic activity (B. Poolman, E. J. Smid, and W. N. Konings, J. Bacteriol. 169:1460-1468, 1987). The decrease in glycolysis is accompanied by a decrease in the activities of glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate mutase. The steady-state levels of pathway intermediates upon refeeding with lactose after various periods of starvation indicate that the decreased glycolysis is primarily due to diminished glyceraldehyde-3-phosphate dehydrogenase activity. Furthermore, quantification of the control strength exerted by glyceraldehyde-3-phosphate dehydrogenase on the overall activity of the glycolytic pathway shows that this enzyme can be significantly rate limiting in nongrowing cells.

Energy Metabolism↗

PubMed1968

Differentiation of Streptococcus faecalis Andrewes and Horder and Streptococcus faecium Orla-Jensen based on the amino acid composition of their murein.

The amino acid composition of the murein (peptidoglycan) of 75 strains of enterococci was investigated. All strains designated Streptococcus faecalis according to their physiological properties contained the lysine-alanine type of murein; all strains classified as S. faecium contained the lysine-aspartic acid type of murein.

Amino Acids↗

PubMed1993

Development and use of species-specific oligonucleotide probes for differentiation of Streptococcus uberis and Streptococcus parauberis.

Oligonucleotide probes specific for 16S rRNA and capable of differentiating Streptococcus uberis and S. parauberis from each other and other esculin-hydrolyzing streptococci were developed. Use of a mini-RNA extraction technique for gram-positive cocci associated with bovine mastitis has allowed the probes to be used for identification of esculin-hydrolyzing streptococci from two dairy herds at the Institute for Animal Health, Compton, United Kingdom. One hundred seventy-nine of 206 isolates were identified as S. uberis, 3 were identified as S. parauberis, and 24 were not identified. Isolates not identified by the probes were tested biochemically and found to be mainly Enterococcus faecium, E. faecalis, or S. bovis.

Animals↗

PubMed1997

Virulent strains of Streptococcus suis serotype 2 and highly virulent strains of Streptococcus suis serotype 1 can be recognized by a unique ribotype profile.

The ribotype profiles of 42 different Streptococcus suis strains were studied. These strains belonged to five serotypes and differed in their virulence for pigs as well as in the expression of the muramidase-released protein and the extracellular protein factor. For the ribotyping, chromosomal DNAs were digested with EcoRI and were hybridized with a 1,066-bp ribosomal DNA probe. The hybridization patterns showed genetic heterogeneity within and between the serotypes. Pathogenic strains of serotype 2 and highly pathogenic strains of serotype 1 could be recognized by their unique ribotype profiles. Nonpathogenic strains showed a high degree of genetic heterogeneity. Moreover, by comparing the 16S ribosomal DNA sequences of a number of S. suis strains, we were able to design two DNA probes which specifically hybridized with S. suis strains.

Bacterial Typing Techniques↗

PubMed2001

16S ribosomal DNA sequence analysis distinguishes biotypes of Streptococcus bovis: Streptococcus bovis Biotype II/2 is a separate genospecies and the predominant clinical isolate in adult males.

We characterized 22 human clinical strains of Streptococcus bovis by genotypic (16S rRNA gene sequence analysis [MicroSeq]; Applied Biosystems, Foster City, Calif.) and phenotypic (API 20 Strep and Rapid ID32 Strep systems (bioMerieux Vitek, Hazelton, Mo.) methods. The strains, isolated from blood, cerebrospinal fluid (CSF), and urine, formed two distinct 16S ribosomal DNA sequence clusters. Three strains which were associated with endocarditis urinary tract infection (UTI), and sepsis clustered with the S. bovis type strain ATCC 33317 (cluster 1); other closely related type strains were S. equinus and S. infantarius. Nineteen strains clustered at a distance of about 2.5% dissimilarity to the S. bovis type strain (cluster 2) and were associated with central nervous system (CNS) disease in addition to endocarditis, UTI, and sepsis. All strains were distinct from S. gallolyticus. Within cluster 2, a single strain grouped with ATCC strain 43143 (cluster 2a) and may be phenotypically distinct. All the other strains formed a second subgroup (cluster 2b) that was biochemically similar to S. bovis biotype II/2 (mannitol negative and beta galactosidase, alpha galactosidase, beta glucuronidase, and trehalose positive). The API 20 Strep system identified isolates of cluster 2b as S. bovis biotype II/2, those of cluster 1 as S. bovis biotype II/1, and that of cluster 2a as S. bovis biotype I. There was an excellent correlation of biotype and genotype: S. bovis biotype II/2 isolates form a separate genospecies distinct from the S. bovis, S. gallolyticus, and S. infantarius type strains and are the most common isolates in adult males.

Adult↗

PubMed2003

Confirmation of nontypeable Streptococcus pneumoniae-like organisms isolated from outbreaks of epidemic conjunctivitis as Streptococcus pneumoniae.

Eleven isolates representing five distinct outbreaks of pneumococcal conjunctivitis were examined for phenotypic and genetic characteristics. None of the strains possessed capsules, and all strains were susceptible to optochin, bile soluble, and Gen-Probe AccuProbe test positive. All 11 isolates were confirmed as Streptococcus pneumoniae by DNA-DNA reassociation experiments.

Conjunctivitis↗

PubMed1978

Brain abscess due to Streptococcus MG-intermedius (Streptococcus milleri).

Three cases of brain abscesses due to Streptococcus MG-intermedius are reported, and the literature pertaining to this subject is reviewed. The importance of careful and complete identification of these etiological agents of infection is stressed. The clinical presentation, the origin of S. MG-intermedius producing brain abscess, and its relation to hepatic abscesses and endocarditis are discussed.

Adolescent↗