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PubMed1982

Sequence relationships between plasmids associated with conventional MLS resistance and zonal lincomycin resistance in Streptococcus pyogenes.

By using electron microscopy of self-annealed DNA and restriction enzyme analysis, we have compared the physical maps of two group A streptococcal plasmids associated with conventional MLS resistance (pEL1; 20 Md) and zonal lincomycin resistance (pSM10419; 15 Md). Of their monomeric molecules, about 40% and 60%, respectively, are occupied by identical non-tandem inverted repeats containing sequences specifying putative replication functions. Sequence homology also exists between their resistance determinants which are located in unique DNA. Moreover, homology between additional regions of unknown function is so extensive and restriction fragment arrangement so similar that, formally, pSM10419 can be considered a deletion variant of pEL1. The results suggest that MLS and zonal lincomycin resistance have the same biochemical basis (i.e. methylation of 23S ribosomal RNA) and differ only quantitatively in the inducible control systems.

Base Sequence↗

PubMed1995

Multiple strains of Streptococcus pyogenes in skin sores of aboriginal Australians.

A molecular technique (random amplification of polymorphic DNA) was used to characterize group A streptococcal (GAS) strains among 194 isolates from 55 swabs from 12 Australian Aboriginal children and adults with multiple pyoderma lesions. Ninety-three percent of the lesions contained only one strain of GAS, but 8 of 12 individuals were infected with more than one strain. We conclude that accurate epidemiologic surveys require that more than one swab specimen be obtained from each person, whereas typing of more than one colony per swab is less informative. Characterization of GAS strains by random amplification of polymorphic DNA analysis should help to provide important insights into the epidemiology of GAS, particularly in tropical populations where many isolates are M nontypeable, and into the mechanisms of genetic variation of GAS in such populations.

Adult↗

PubMed1997

Prevalence of the speA2 and speA3 alleles in Streptococcus pyogenes isolated from TSLS patients in Japan.

More than 100 cases have been identified as streptococcal toxic shock-like syndrome (TSLS) in Japan, since the first case was reported in 1993. Of 26 S. pyogenes isolates associated with TSLS, 69% were M-types 1 and 3. This study focused on speA alleles which were carried by all M-type 1 and 3 isolates and isolates of some other M-types, irrespective of sources. We sequenced the nucleotides of the relevant region of the speA allele in all of these isolates. Consistent with other reports, these M-type 1 and 3 isolates carried the speA2 and speA3 alleles, respectively. Our results indicate that these two speA alleles, which were prevalent world-wide have been disseminating in Japan.

Alleles↗

PubMed2001

Stability and DNA-binding properties of the omega regulator protein from the broad-host range Streptococcus pyogenes plasmid pSM19035.

At the transcriptional level, the pSM19035-encoded omega protein coordinates the expression of proteins required for control of copy number and maintenance of plasmids. Using circular dichroism, fluorescence spectroscopy, ultracentrifugation and an electrophoretic mobility shift assay, the wild-type omega protein and a variant with a C-terminal hexa-histidine tag (omega-H(6)) were characterized. The omega protein is mainly alpha-helical (42%), occurs as homodimer in solution, unfolds thermally with half transition temperatures, T(m), between approximately 43 and approximately 78 degrees C depending on the ionic strength of the buffer, and binds PcopS-DNA with high affinity. The omega-H(6) protein has a modified conformation with lower alpha-helix content (29%), lower thermal stability, and strongly reduced affinity to PcopS-DNA.

Bacterial Proteins↗

PubMed1994

Production and partial characterization of monoclonal antibodies against erythrogenic toxins type A and C from Streptococcus pyogenes.

Hybridoma cell lines producing monoclonal antibodies against streptococcal erythrogenic toxins type A and C were established from fusions of immunized BALB/c mice splenocytes with P3X63-Ag8.653 myeloma cells. Six MAbs recognize ETA and 11 MAbs bind to ETC. Two MAbs (designated ETA-2 and ETC-10) were produced in ascitic fluid and further characterized. ETA-2 (IgG2a) binds to ETA with an affinity constant of 1.8 x 10(10) M-1 and ETC-10 (IgG1) binds to ETC with an affinity constant of 3.5 x 10(9) M-1. The specificities of the MAbs were evaluated by ELISA and immunoblotting. Both MAbs ETA-2 and ETC-10 are useful in developing specific double-sandwich ELISAs, in which the MAbs were used as solid-phase capture antibodies for the quantitative determinations of ETA and ETC.

Animals↗

PubMed1995

Streptococcus pyogenes bacteremia: a retrospective study in a Belgian university hospital.

We retrospectively studied 29 cases of S.pyogenes bacteremia, treated from September 1985 through September 1993, in order to define the clinical pattern, predisposing factors and the outcome of S.pyogenes bacteremia in our region. The number of infections, the clinical picture and mortality rate of S.pyogenes bacteremia did not change during the study period and only 2 of 29 cases presented with a fulminant clinical course, meeting the criteria of streptococcal toxic shock syndrome. In many patients, predisposing factors such as skin abnormalities (n = 14) and airway diseases (n = 10) could be identified. Patients with underlying skin disease were mostly characterized by a clinically benign bacteremia with good prognosis. We suspect that the recently reported so-called rising incidence of severe S.pyogenes infections might be due to epidemiologic clustering and selection bias in certain regions.

Adolescent↗

PubMed2006

Method for the synthesis of multi-epitopic Streptococcus pyogenes lipopeptide vaccines using native chemical ligation.

The aim of this study was to investigate methods for the synthesis of highly pure, well-characterized analogues of the lipid core peptide (LCP) system. Difficulties synthesizing and purifying conventional LCP systems have led to the requirement for a technique to produce highly pure, LCP-based vaccines for potential use in human clinical trials. The current study describes methods for the attachment of lipophilic adjuvants onto multi-epitopic peptide vaccines. Described is the synthesis, using native chemical ligation, of a highly pure, tri-epitopic, group A streptococcal (GAS) lipopeptide vaccine candidate. Intranasal immunization of the described tri-epitopic GAS lipopeptide with the mucosal adjuvant cholera toxin B subunit induced high serum IgG antibody titers specific for each of the incorporated peptide epitopes.

Adjuvants, Immunologic↗

PubMed1998

Invasion and survival of Streptococcus pyogenes in eukaryotic cells correlates with the source of the clinical isolates.

The invasiveness of 96 group A streptococci (GAS) isolates (56 from throat or skin and 40 from blood) were analyzed. GAS invasion strongly correlated with the source of the isolates, whereas no correlation was observed with the Vir type. Isolates from throat or skin exhibited the highest invasion efficiency (57% were between 0.1% and 10%). In contrast, 77.5% of the blood isolates were noninvasive (efficiency <0.01%) and only 7.5% exhibited rates comparable to those of throat or skin isolates (>0.1%). Immunofluorescence studies of 34 selected isolates showed that attachment and invasion are strain-related. Although isolates with high invasiveness usually exhibit high attachment, isolates that showed high attachment and no invasion or poor attachment and efficient internalization were identified. The ability of GAS to invade and survive within eukaryotic cells may provide bacteria a sure niche, in which they are protected against host defense mechanisms or antimicrobial agents favoring their local persistence.

Adhesins, Bacterial↗

PubMed2000

Relationship between asymptomatic carriage of Streptococcus pyogenes and the ability of the strains to adhere to and be internalised by cultured epithelial cells.

This study was undertaken to determine whether the ability of group A streptococci to persist in the throat following antibiotic therapy corresponded with their capacity to adhere to and be internalised by epithelial cells. The study employed a HEp-2 cell model to examine the adherence and internalisation capacities of 42 strains (13 from asymptomatic patients with bacteriological eradication failure and 29 from patients with bacterial eradication). The adherence and internalisation efficiencies of strains from symptomless carriers were significantly higher. The average adherence efficiency of the carriers' strains was 53 (SEM 6)% versus 35 (SEM 5)% in control strains. The average internalisation efficiency of the carriers' strains was 13.4 (SEM 4)% compared with 4.4 (SE 1.6)% in the control group. The results are in agreement with the hypothesis that, in a significant number of cases, streptococcal internalisation might contribute to eradication failure and persistent throat carriage.

Anti-Bacterial Agents↗

PubMed1988

Berberine sulfate blocks adherence of Streptococcus pyogenes to epithelial cells, fibronectin, and hexadecane.

Berberine sulfate is an alkaloid extracted from the roots and bark of various plants and possesses antibacterial, antifungal, and antiprotozoal activities. Most studies have focused on the bacteriostatic or bactericidal activities of this compound. In this study, we report that berberine sulfate is bacteriostatic for streptococci and that sub-MICs of berberine blocked the adherence of streptococci to host cells, immobilized fibronectin, and hexadecane. Concentrations of berberine below its MIC caused an eightfold increase in release of lipoteichoic acid from the streptococci. Higher concentrations of berberine directly interfered with the adherence of streptococci to host cells either by preventing the complexing of lipoteichoic acid with fibronectin or by dissolution of such complexes once they were formed. Thus, berberine sulfate interferes with the adherence of group A streptococci by two distinct mechanisms: one by releasing the adhesin lipoteichoic acid from the streptococcal cell surface and another by directly preventing or dissolving lipoteichoic acid-fibronectin complexes.

Alkanes↗

PubMed2001

Kinetic properties of fractions of extracellular NAD+ nucleosidase from Streptococcus pyogenes as an example of host selection by a pathogen: possible role of serum albumin in the organism.

Preparative isoelectric focusing was used to separate free bacterial NAD+ nucleosidase from its complex with a bound host component. Both fractions were characterized by optimum temperature and activation energy of denaturation. The bacterial product is enzymically inactive. The enzymically active structure is formed upon binding to the host component. Only the host organism can provide the suitable, activating structure. The host component in the present system is added to the cultivation medium with a beef heart extract but it can be replaced by serum albumin. The possible role of albumin as a carrier structure for flexible and enzymically inactive peptides is discussed. Different peptides bound to albumin can provide different enzyme activities. The term binary enzyme is coined, referring to a situation where the two enzyme components are coded at genetically distant loci. The pathogen makes use of the carrier structure of albumin type and produces another polypeptide invested with an enzyme activity convenient for the pathogen.

Culture Media↗

PubMed2000

Analysis of plasminogen-binding M proteins of Streptococcus pyogenes.

Group A streptococci are common human pathogens that cause a variety of infections. They express M proteins which are important cell wall-bound type-specific virulence factors. We have found that a set of strains, associated primarily with skin infections, express M proteins that bind plasminogen and plasmin with high affinity. The binding is mediated by a 13-amino-acid internal repeated sequence located in the N-terminal surface-exposed portion of these M proteins. This sequence binds to kringle 2 in plasminogen, a domain that is not involved in the interaction with streptokinase, a potent group A streptococcal activator of plasminogen. It could be demonstrated that plasminogen, absorbed from plasma by growing group A streptococci expressing the plasminogen-binding M proteins, could be activated by exogenous and endogenous streptokinase, thereby providing the bacteria with a surface-associated enzyme that could act on the tissue barriers in the infected host.

Antigens, Bacterial↗

PubMed1973

Inducible and constitutive resistance to macrolide antibiotics and lincomycin in clinically isolated strains of Streptococcus pyogenes.

STUDIES ON ERYTHROMYCIN RESISTANCE IN STRAINS OF GROUP A STREPTOCOCCI INDICATED THAT THEY WERE COMPRISED OF TWO TYPES: (i) an inducible, resistant type (IR strains) was seen, which manifested immediate logarithmic growth in media containing high concentrations of the drug only after brief previous exposure (induction period) of the organisms to subinhibitory concentrations of erythromycin, and (ii) a constitutive, resistant type (CR strains) which demonstrated, without prior drug exposure, continued logarithmic growth in media containing high concentrations of erythromycin. Subinhibitory concentrations of either chloramphenicol or puromycin, when added to IR strains prior to induction, interfered with their induction by erythromycin. Exposure of CR strains to chloramphenicol did not visibly affect the subsequent growth curve of these strains in media containing high concentrations of erythromycin. In IR strains, resistance to other macrolide antibiotics (oleandomycin, spiramycin, carbomycin, magnamycin) and to lincomycin also was inducible in nature. There was cross-inducibility between erythromycin, other macrolide antibiotics, and lincomycin. CR strains were constitutively resistant to these antibiotics.

Anti-Bacterial Agents↗

PubMed1993

[Comparative in vitro activity of new oral macrolides against Streptococcus pyogenes strains].

Some recently introduced macrolides have several clinical advantages over erythromycin. Azithrommcin, a prototype of these new macrolides could be a good alternative for the treatment of streptococcal pharyngitis, even over penicillin, whose failure rate can be as high as 30%. The aim of this study was to evaluate the in vitro susceptibility of 120 strains of S pyogenes isolated between 1990 and 1992 (40 per year), from diverse infections (specially tonsillitis). We determined Minimal Inhibitory Concentrations (MIC) of azithromycin, clarithromycin, roxithromycin, erythromycin and penicillin using the agar dilution method and the Minimal Bactericidal Concentration (MBC) by tube dilution for azythromycin and erythromycin. The MIC 90 for the new macrolides ranged from 0.03 to 0.12 microgram/ml, and was 0.03 microgram/ml for erythromycin and penicillin (not different). All strains were susceptible to all antibiotics and the date of isolation did not influence susceptibility. The MBC for azithromycin was 0.12 microgram/ml (identical to its MIC), which demonstrates the bactericidal effect of this antibiotic. It is concluded that this in vitro data supports the potential role of these new macrolides in the treatment of streptococcal infections.

Anti-Bacterial Agents↗

PubMed1997

M protein mediated adhesion of M type 24 Streptococcus pyogenes stimulates release of interleukin-6 by HEp-2 tissue culture cells.

We investigated the contributions of lipoteichoic acid and M protein to reversible and irreversible adhesion of group A streptococci and the effects of such adhesion on release of interleukin-6. Streptococci in which lipoteichoic acid was masked by the hyaluronate capsule were readily washed from HEp-2 cells, indicating no attachment. Unencapsulated, M-negative streptococci in which lipoteichoic acid was exposed were removed more slowly, indicating loose attachment. Only unencapsulated streptococci that expressed both lipoteichoic acid and M protein remained stably adherent to HEp-2 cells throughout multiple washes. Streptococci expressing both M protein and lipoteichoic acid induced release of interleukin-6 from HEp-2 cells, whereas an isogenic, M-negative mutant failed to induce release of interleukin-6. These data suggest that lipoteichoic acid mediates reversible adhesion and that M protein is required for irreversible adhesion and for inducing release of interleukin-6 from HEp-2 cells.

Antigens, Bacterial↗

PubMed1976

Complex surveillance of Streptococcus pyogenes. III. Immunological characteristics of streptococcal resistance in blood and new aspects of type nonspecific protection.

The influence of nonspecific immunity factors in indifferent human blood on the resistance of M non-typable field streptococci and collection M strains in the absence of anti-M antibodies was studied. The experimental results indicate that primary resistance is conditioned on balanced equipment of the strain with M protein and the nonspecific cofactor receptor [R]. Disbalanced strains were strongly phagocytized, with participation by nonspecific opsonins (complement C3 and nonspecific cofactor), irrespective of their M protein content. M + R--disbalance (selected collection strains) and M--R + disbalance (field strains on artificial media) were observed. The M and R resistance factor equipment of the streptococci probably represents plus and minus variants in the diverse process of the asymptomatic dissemination and pathogenic activity of streptococci in the human population. The given results are manifestly related to the general manner of existence of streptococci, to questions of conditional pathogenicity and to the concept of nonspecific defence against streptococci.

Antibody Specificity↗

PubMed1988

DNA fingerprints of Streptococcus pyogenes are M type specific.

DNA from group A streptococci of various M and T types was cleaved with endonucleases to produce a DNA fingerprint. Comparison of DNA fingerprints proved to be a very useful tool for studying the epidemiology of isolates from various outbreaks of streptococcal disease. Patterns of DNA fragments from HindIII digests of samples of total DNA were conserved among strains of the same M serotype yet were easily distinguished from those of different M serotypes. Different M types were associated with specific restriction enzyme profiles. DNA fingerprints of strains of the same M type were stable enough to establish a clonal relationship between strains obtained from an isolated outbreak of disease or strains endogenous to people geographically isolated by continent. Strains of the same serotype from different continents had very similar, but distinguishable, restriction profiles. Those strains unable to be typed with standard typing sera were also amenable to comparison because they yielded unique fingerprints.

Africa↗

PubMed1982

[Clinical evaluation, in the field of pediatrics, of a microagglutination test for research on anti-polysaccharide antibodies of a group of Streptococcus pyogenes].

The diagnostic and prognostic utility of a new microagglutination test for the evaluation of antibodies to group A streptococcal polysaccharide are evaluated in different streptococcal and post-streptococcal diseases. The basal titers of a group of 834 children from 1 to 12 years old non affected with apparent or recent streptococcal infections are examined to establish the normal values related to age. From this study, it results the diagnostic utility of the test especially in pharyngotonsillar, pulmonary, pyodermitic, adenitic, glomerulonephritic infections and in the Schoenlein-Henoch syndrome. Particularly in little children, even under 1 year old, the antigenic stimulation of antibodies to group A streptococcal polysaccharide is very good, on the contrary at this age the anticorpoiesis against streptococcal extracellular antigens is not very efficacious. Persistence beyond a year of elevated values of antipolysaccharide antibodies are observed in rheumatic disease with carditis and also in rheumatic disease without carditis, in glomerulonephritis and in common streptococcal infections in 11.1-68% of cases. The possible prognostic significance of these data is discussed.

Agglutination Tests↗