PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Streptococcus pyogenes”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed1997

Transmission of Streptococcus pyogenes causing toxic shock-like syndrome among family members and confirmation by DNA macrorestriction analysis.

Streptococcus pyogenes can cause severe infections, such as toxic shock-like syndrome (TSLS). The transmission and pathogenesis of TSLS are poorly understood, and information is needed to develop prevention strategies. Four cases were identified in which the organism was transmitted among patients with TSLS and their family members. DNA macrorestriction endonuclease analysis using pulsed-field gel electrophoresis demonstrated the spread of S. pyogenes clones that caused TSLS among the family members. Although 14 persons related to the case-patients experienced only colonization or self-limited disease, 3 developed invasive infections (pneumonia, severe pharyngitis requiring hospitalization, and puerperal sepsis). These findings indicate that antimicrobial prophylaxis for close contacts of patients with TSLS should be considered and reinforce the need for further studies on epidemic control of TSLS.

Adult↗
PubMed2006

Unraveling the regulatory network in Streptococcus pyogenes: the global response regulator CovR represses rivR directly.

The response regulator CovR acts as a master regulator of virulence in Streptococcus pyogenes by repressing transcription of approximately 15% of the group A streptococcus genome directly or indirectly. We demonstrate that phosphorylated CovR represses transcription of rivR directly by binding to conserved sequences located downstream from the promoter to block procession of RNA polymerase. This establishes the first link in a regulatory network where CovR interacts directly with other proteins that modulate gene expression.

Bacterial Proteins↗
PubMed1999

Nucleotide sequence of the streptococcin A-FF22 lantibiotic regulon: model for production of the lantibiotic SA-FF22 by strains of Streptococcus pyogenes.

Streptococcin A-FF22 (SA-FF22) is a type AII linear lantibiotic produced by Streptococcus pyogenes strain FF22. Sequence analysis of an approximate 10 kb region of DNA showed it to contain nine open reading frames arranged in three operons responsible for regulation, biosynthesis and immunity of SA-FF22. This region is organized similarly to the Lactococcus lactis lacticin 481 region, however, unlike lacticin 481, a two-component regulatory system is essential for SA-FF22 production. Located immediately downstream of the scn region is a putative transposase gene, the presence of which supports earlier data that indicated a mobile nature to this region.

Amino Acid Sequence↗
PubMed1998

M genotyping and DNA fingerprinting of Streptococcus pyogenes isolates from an area of central Italy.

M protein gene typing was used to analyse Streptococcus pyogenes clinical isolates collected between 1983 and 1995 in an area of central Italy from patients presenting different types of infections; the same isolates were also characterized by means of DNA fingerprinting. M type 1 was the most common (50% of study strains), followed by M types 4, 12 and 6. The proportion of M type 12 decreased with time, whereas M type 1 increased, in agreement with data obtained in many different areas. Most invasive strains belonged to types M1 (30%) and M12 (30%); on the other hand, the M1 type did frequently occur also among non-invasive isolates. DNA fingerprinting showed a correlation between M types and DNA patterns. This report provides epidemiological information from a geographic area not sampled recently, and further shows the usefulness of the M genotyping technique, which offers potential advantages over conventional serological typing methods.

DNA Fingerprinting↗
PubMed1980

[Purification and characterization of erythrogenic toxins. I. Investigation of erythrogenic toxin A produced by Streptococcus pyogenes strain NY-5 (author's transl)].

An erythrogenic toxin was isolated from culture supernatants of Streptococcus pyogenes, strain NY-5 (type 12) grown in yeast extract-pepton-dialysate medium. After concentration by evaporation, a crude material was obtained by precipitation with ethanol. This material was prepurified by ion exchange chromatography using a DEAE-Sepharose Cl-6B column. After precipitation of the active material with (NH4)2SO4 the redissolved precipitate was dialyzed against acetate buffer and rechromatographed on a CM-Sepharose Cl-6B column. The toxin was obtained by stepwise elution with 0.02 M acetate buffer, pH 5.0, and 0.05 M phosphate buffer, pH 6.5, followed by a last purification step on a Sephacryl S-200 column. The purified toxin behaved homogenously in SDS electrophoresis, the molecular weight being about 28 000. Amino acid analysis showed only one cysteine residue per molecule. The molecule was insensitive to 2-mercaptoethanol and alkylation. Isoelectric focusing yielded two narrow bands having an isoelectric point of 5.2. The toxin showed a serological reaction of identity with an antiserum against streptococcal pyrogenic exotoxin A (SPE-A) but was shown to have a different molecular weight. The purified material (erythrogenic toxin A) was pyrogenic and toxic for rabbits as well as mitogenic for human lymphocytes. A positive skin reaction in guinea pigs could be obtained by as little as 5 X 10(-8) mg.

Amino Acids↗
PubMed2003

The luxS gene of Streptococcus pyogenes regulates expression of genes that affect internalization by epithelial cells.

The gram-positive pathogen Streptococcus pyogenes was recently reported to possess a homologue of the luxS gene that is responsible for the production of autoinducer 2, which participates in quorum sensing of both gram-positive and gram-negative bacteria. To test the effect of LuxS on streptococcal internalization, a LuxS mutant was constructed in strain SP268, an invasive M3 serotype. Functional analysis of the mutant revealed that it was internalized by HEp-2 cells with higher efficiency than the wild type (wt). Several genes, including hasA (hyaluronic acid synthesis), speB (streptococcal pyrogenic exotoxin B), and csrR (capsule synthesis regulator), a part of a two-component regulatory system, are known to affect the internalization of strain SP268 (J. Jadoun, O. Eyal, and S. Sela, Infect. Immun. 70:462-469, 2002). Therefore, the expression of these genes in the mutant and in the wt was examined. LuxS mutation significantly reduced the mRNA level of speB and increased the mRNA level of emm3. No substantial effect was observed on transcription of hasA and csrR. Yet less hyaluronic acid capsule was expressed in the mutant. Further analysis revealed that luxS is under the regulation of the two-component global regulator CsrR. Our results indicate that LuxS activity in strain SP268 plays an important role in the expression of virulence factors associated with epithelial cell internalization.

Bacterial Proteins↗
PubMed2006

Proteomic analysis of a penicillin-tolerant rgg mutant strain of Streptococcus pyogenes.

OBJECTIVES: To determine whether the transcriptional regulator Rgg contributes to penicillin-induced killing of Streptococcus pyogenes by altering a regulatory response to penicillin. METHODS: Penicillin-induced killing of a wild-type and isogenic rgg mutant strain was assessed in broth and solid media and in the presence of cerulenin, which inhibits fatty acid biosynthesis (FAB). Proteins from wild-type and rgg mutant cultures, either exposed to penicillin or not, were characterized by two-dimensional gel electrophoresis. Proteins of interest were identified with tandem mass spectrometry. RESULTS: The MIC of penicillin was 0.012 mg/L for both the wild-type strain NZ131 and an isogenic rgg mutant strain. The wild-type strain lost 1.9 log(10) cfu/mL ( approximately 80-fold) after 24 h of exposure to 0.024 mg/L penicillin compared with controls; however, the mutant strain lost 0.3 log(10) cfu/mL ( approximately 2-fold) compared with controls. Changes in the proteome of wild-type and mutant cultures were assessed 1 and 4 h after exposure to penicillin. One hour exposure was associated with increased abundance (P < 0.05) of 12 proteins associated with FAB, the pentose phosphate pathway, glycolysis and stress responses in the wild-type strain. The abundance of 8 of 12 of these proteins was greater in samples obtained from the mutant strain, even prior to penicillin exposure. After 4 h of exposure, the abundance of 16 proteins was altered in one or both strains; however, a clear functional relationship was not evident. The addition of cerulenin slightly enhanced penicillin-induced killing of wild-type strain, which supported the proteomic results. CONCLUSIONS: The results suggest that penicillin-independent changes in the cytoplasmic proteome of an rgg mutant strain of NZ131 confer tolerance to penicillin-mediated killing.

Bacterial Proteins↗
PubMed1995

Mitogenicity of M5 protein extracted from Streptococcus pyogenes cells is due to streptococcal pyrogenic exotoxin C and mitogenic factor MF.

M proteins of Streptococcus pyogenes are virulence factors which impede phagocytosis, bind to many plasma proteins, and induce formation of cross-reactive autoimmune antibodies. Recently, it has been reported that some M proteins, extracted with pepsin from streptococci (pep M), are superantigens. One of these, pep M5, was investigated in detail and was shown to stimulate human T cells bearing V beta 2, V beta 4, and V beta 8. In the present study, we extracted and purified M5 protein by different biochemical methods from two M type 5 group A streptococcal strains. The crude extracts were fractionated by affinity chromatography and ion-exchange chromatography. All fractions were tested in parallel for M protein by immunoblotting and for T-cell-stimulating activity. Although several crude preparations of M5 protein were associated with mitogenicity for V beta 2 and V beta 8 T cells, the M5 proteins, irrespective of the extraction method, could be purified to the extent that they were no longer mitogenic. The mitogenic activity was not destroyed during the purification procedures but was found in fractions separated from M protein. In these fractions, streptococcal pyrogenic exotoxin C and mitogenic factor MF could be detected by protein blotting and enzyme-linked immunosorbent assay. Moreover, anti-M protein sera did not inhibit the mitogenic activity of crude extracts, but antisera which contained anti-streptococcal pyrogenic exotoxin C antibodies showed inhibition. The inability of M5 protein to stimulate T cells was confirmed with recombinant pep M5 produced in Escherichia coli. Our data strongly suggest that the mitogenic activity in M protein preparations is caused by traces of streptococcal superantigens different from M protein.

Amino Acid Sequence↗
PubMed1993

Rapid detection of Streptococcus pyogenes in pediatric patient specimens by DNA probe.

A chemiluminescent DNA probe test (Group A Streptococcus Direct Test; Gen-Probe, Inc., San Diego, Calif.) for rapid, direct detection of cRNA of Streptococcus pyogenes in throat swabs was compared with conventional culture and identification techniques. Throat swabs from 277 patients suspected of having streptococcal pharyngitis were examined. By DNA probe alone, 10 specimens were positive, 51 were positive by both assays, and 8 were positive by culture alone. Thus, DNA probe sensitivity, specificity, and positive and negative predictive values were 86, 95, 84, and 96%, respectively. Including an indeterminate category, sensitivity, specificity, and positive and negative predictive values were 89, 96, 86, and 97%, respectively. After discrepancy testing, these values for the raw data improved to 90, 98, 93, and 97%, respectively. None of the 24 specimens that grew non-S. pyogenes beta-hemolytic streptococci in culture were positive by the DNA probe. Because mucoid S. pyogenes strains are more virulent than nonmucoid strains, 24 isolates were retrospectively tested with the DNA probe to ensure that both types would be detected equally well. Isolates were examined in pure cultures as well as mixed with representative normal oral flora. There was no statistical difference in detection of any of the four groups. Group A Streptococcus Direct Test is a rapid, sensitive, and specific test for S. pyogenes.

Child↗
PubMed1991

Electrotransformation of Streptococcus pyogenes with plasmid and linear DNA.

Electrotransformation was used to introduce both plasmid and linear DNA into Streptococcus pyogenes. The method was optimized using strain NZ131, for which transformation frequencies up to 10(7) per micrograms of plasmid DNA were obtained. A linear fragment of DNA, containing the streptokinase gene (ska) in which an internal fragment had been replaced with an erythromycin resistance gene (erm), was transformed into strain NZ131 with a frequency of 10(3) per micrograms DNA. The introduction of linear DNA into S. pyogenes by electrotransformation should be useful for future genetic analyses as well as targeted gene replacement.

Blotting, Southern↗
PubMed2002

Distribution of emm genotypes and superantigen genes of Streptococcus pyogenes isolated in Japan, 1994-9.

The purpose of this study was to examine characteristic profiles of Streptococcus pyogenes clinical isolates isolated in Japan during 1994-9. Genotyping of the M protein (emm typing) revealed that emm types 12 and 28 were the most common among 316 isolates. Most of the emm12 isolates were isolated from mucosa, while emm58 and emm89 were from skin. Moreover, the emm3 isolates were dominant in invasive infections. The distribution of 6 superantigen genes showed that all isolates harboured the mf gene and many had the speG gene. Invasive isolates were shown to have the ssa gene at a higher rate (76%) than noninvasive (37%). The distribution of superantigens was significantly different between emm types, but not between isolation sites. These results suggest that the distribution of emm types is related to isolation site, whereas superantigen distribution is related to clinical features of S. pyogenes infections.

Antigens, Bacterial↗
PubMed1994

[M-typing of Streptococcus pyogenes by latex agglutination using monoclonal antibody. Streptococcal Diseases Study Group].

The Lancefield's serotyping system of Streptococcus pyogenes is based on the M protein. The typing sera used for this system are prepared in rabbits immunized with whole organisms of specific serotypes. To remove cross reactive antibodies, the sera should be extensively absorbed with organisms of selected heterologous serotypes. In this study, the possibility of using monoclonal antibody (MAb) as a type specific reagent was discussed. MAb which specifically reacted to M type 12 protein of S. pyogenes were produced by cell fusion. This specific MAb reacted to hot acid extracted M type 12 protein in ELISA but didn't react in agglutination and precipitation. Latex beads were sensitized with MAb and examined by the coagglutination method. The latex reagent could detect a very small amount of M type 12 protein, so it could be used for M typing of S. pyogenes which produced a small amount of M 12 protein.

Animals↗
PubMed2001

Remarkable attachment of lactoferrin to Streptococcus pyogenes during acute pharyngotonsillitis.

The purpose of this study was to establish whether lactoferrin (hLf) attached to Streptococcus pyogenes, one causative agent of acute pharyngotonsillitis (AT), during the course of the disease. Bacterial samples were obtained from the tonsillar surfaces of 7 patients (6 females, 1 male; median age 26 years; range 16-50 years) suffering from AT who were culture-positive for S. pyogenes and from 5 healthy adult controls who were culture-negative for this pathogen. Using gold-labelled antiserum against S. pyogenes and hLf, this pathogen and other bacteria on the tonsillar surfaces coated with hLf could be identified by tracing the gold particles in a transmission electron microscope. In healthy adults, 8% (median value; range 6-12%) of the surface tonsillar bacteria were coated with hLf. In AT patients, 59% (median value; range 42 67%) of S. pyogenes were coated with hLf, in contrast to 9% (median value; range 0-26%) of all other bacteria (p < 0.01). This study hints that hLf might participate in recovery from AT in several ways, e.g. by binding to the S. pyogenes pathogens, in addition to its well-known virtue of iron-binding capacity.

Acute Disease↗
PubMed1998

Expression of heat-shock proteins in Streptococcus pyogenes and their immunoreactivity with sera from patients with streptococcal diseases.

The heat-shock response of Streptococcus pyogenes following exposure to elevated growth temperatures, and the immunological reactivity of heat-shock proteins (HSPs) in streptococcal infections were studied. Two major proteins of 65 and 75 kDa were expressed when a S. pyogenes strain was shifted from 37 degrees C to heat-shock temperatures of 40, 42 and 45 degrees C. Such proteins are members of the GroEL and DnaK families recognised in a Western blot assay with polyclonal antibodies against Escherichia coli GroEL and E. coli DnaK, respectively. Two-dimensional autoradiograms of polypeptides labelled at 37 or 42 degrees C showed an increased intensity of three spots at 42 degrees C. A monoclonal antibody (MAb) against HSP 63 of Bordetella pertussis also recognised the 65-kDa inducible protein, although MAbs against Mycobacterium tuberculosis HSP 65 failed to recognise this protein. Immunoblot analysis of sera from individuals with rheumatic fever or uncomplicated streptococcal diseases revealed seven major immunogenic protein bands, two of which also reacted with anti-E. coli GroEL and DnaK polyclonal antibodies. Furthermore, antibodies to the GroEL and DnaK proteins were also detected in sera from patients with either rheumatoid arthritis or systemic lupus erythematosus. These results demonstrated a heat-shock response of S. pyogenes, and indicated the presence of an immune response against HSPs in streptococcal diseases.

Arthritis, Rheumatoid↗
PubMed2004

Contribution of glutathione peroxidase to the virulence of Streptococcus pyogenes.

Glutathione peroxidases are widespread among eukaryotic organisms and function as a major defense against hydrogen peroxide and organic peroxides. However, glutathione peroxidases are not well studied among prokaryotic organisms and have not previously been shown to promote bacterial virulence. Recently, a gene with homology to glutathione peroxidase was shown to contribute to the antioxidant defenses of Streptococcus pyogenes (group A streptococcus). Since this bacterium causes numerous suppurative diseases that require it to thrive in highly inflamed tissue, it was of interest to determine if glutathione peroxidase is important for virulence. In this study, we report that GpoA glutathione peroxidase is the major glutathione peroxidase in S. pyogenes and is essential for S. pyogenes pathogenesis in several murine models that mimic different aspects of streptococcal suppurative disease. In contrast, glutathione peroxidase is not essential for virulence in a zebrafish model of streptococcal myositis, a disease characterized by the absence of an inflammatory cell infiltrate. Taken together, these data suggest that S. pyogenes requires glutathione peroxidase to adapt to oxidative stress that accompanies an inflammatory response, and the data provide the first demonstration of a role for glutathione peroxidase in bacterial virulence. The fact that genes encoding putative glutathione peroxidases are found in the genomes of many pathogenic bacterial species suggests that glutathione peroxidase may have a general role in bacterial pathogenesis.

Animals↗
PubMed1993

Protein F: an adhesin of Streptococcus pyogenes binds fibronectin via two distinct domains.

The binding of Streptococcus pyogenes to fibronectin (FN) enables the adherence of this pathogen to target epithelial cells, which is the first necessary step for initiation of infection. Binding is mediated by a bacterial surface protein termed protein F. Here we provide the complete structure of protein F and identify two domains responsible for binding to fibronectin. The first domain is located towards the C-terminal end of the molecule and is composed of five repeats of 37 amino acids that are completely repeated four times and a fifth time partially. The second domain is adjacent to the first domain and is located on the N-terminal side of it. It is composed of a single stretch of 43 amino acids. Protein F expressed in Escherichia coli completely blocked the binding of fibronectin to S. pyogenes. However, mutant proteins that contained only one or the other of the two domains were only capable of partial blockage of binding. Complete blockage of binding of fibronectin could be achieved when a protein extract containing the N-terminal domain was mixed in a binding reaction with a protein extract containing the C-terminal domain. Similarly, a purified recombinant protein containing the two domains only, blocked the binding completely. In contrast, a purified recombinant protein containing just the C-terminal domain, blocked the binding partially. A clone exclusively expressing the C-terminal domain, completely blocked the binding of the 30 kDa N-terminal fragment of fibronectin to S. pyogenes, whereas a clone expressing the N-terminal domain failed to block the binding of this FN fragment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesins, Bacterial↗
PubMedDate not supplied

Antiproliferative and apoptosis-inducing effects of an antitumor glycoprotein from Streptococcus pyogenes.

An acidic glycoprotein (SAGP) purified from an extract of Streptococcus pyogenes has been shown to inhibit the growth of methylcholanthrene-induced fibrosarcoma A (Meth A) cells via pertussis toxin-sensitive GTP-binding protein. The present study revealed that SAGP has activity to induce apoptosis in Meth A cells as assessed by DNA fragmentation and cell morphology with chromatin staining. The SAGP-induced DNA fragmentation in Meth A cells was augmented by herbimycin A, an inhibitor of protein tyrosine kinase, and prevented by orthovanadate, an inhibitor of protein tyrosine phosphatase. The growth inhibitory effect of SAGP on Meth A cells was reduced by orthovanadate, whereas the effect tended to be increased by herbimycin A. Western blotting analysis using antiphosphotyrosine antibody demonstrated that tyrosine phosphorylation of 170 kDa cellular protein was diminished in the cells incubated with SAGP. The inhibition of protein tyrosine phosphorylation was neither observed in the cells incubated with SAGP and orthovanadate nor in the cells incubated with heat-inactivated SAGP. These findings indicate that inhibition of tyrosine phosphorylation by protein tyrosine phosphatase(s) may be responsible for the SAGP-induced apoptosis and inhibition of cell growth.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗