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PubMed1999

Identification and characterization of a Streptococcus pyogenes ABC transporter with multiple specificity for metal cations.

Metal ions are crucial trace elements for bacteria infecting the human host. The LraI (lipoprotein receptor-associated antigen I) transporter in Streptococcus spp. belongs to the superfamily of ABC transporters. The transporter consists of a lipoprotein, an ATP-binding protein and a hydrophobic integral membrane protein. Here, we describe a new member of the LraI family in the important human pathogen Streptococcus pyogenes. The system was identified in silico by analysis of the S. pyogenes Genome Sequencing Project. The S. pyogenes operon exhibits an atypical organization compared with equivalents in other Streptococcus spp. The presence and atypical organization of the operon was verified in a number of S. pyogenes strains of different serotypes. Transcriptional analysis of the LraI operon demonstrates a polycistronic transcription attenuated by a stable stem-loop structure, which allows the lipoprotein to be expressed in larger quantities than the other two components. The localization of the native lipoprotein at the bacterial surface was shown by proteolytic digestion of S. pyogenes bacteria and NH2-terminal sequencing of a released lipoprotein fragment. Recombinant lipoprotein was expressed as a GST fusion protein, and studies of molecular interactions with metal radioisotopes demonstrated that the protein has affinity for Zn(II), Fe(III) and Cu(II). Zn(II) and Cu(II) were found to compete for the same binding site, whereas Fe(III) uses a second site. Also, proton-induced X-ray analysis of lipoprotein samples identified iron, copper and zinc. Finally, a mutant strain lacking a functional mtsABC operon was generated and showed reduced uptake of 55Fe and 65Zn compared with the wild-type strain. The operon encoding this novel ABC transporter with multiple specificity for metal cations is designated mtsABC, for metal transporter of Streptococcus.

ATP-Binding Cassette Transporters↗
PubMed1999

High-resolution genotyping of Streptococcus pyogenes serotype M1 isolates by fluorescent amplified-fragment length polymorphism analysis.

We have used fluorescent amplified-fragment length polymorphism (FAFLP) analysis to subtype clinical isolates of Streptococcus pyogenes serotype M1. Established typing methods define most M1 isolates as members of a clone that has a worldwide distribution and that is strongly associated with invasive diseases. FAFLP analysis simultaneously sampled 90 to 120 loci throughout the M1 genome. Its discriminatory power, precision, and reproducibility were compared with those of other molecular typing methods. Irrespective of disease symptomatology or geographic origin, the majority of the clinical M1 isolates shared a single ribotype, pulsed-field gel electrophoresis macrorestriction profile, and emm1 gene sequence. Nonetheless, among these isolates, FAFLP analysis could differentiate 17 distinct profiles, including seven multi-isolate groups. The FAFLP profiles of M1 isolates reproducibly exhibited between 1 and more than 20 amplified fragment differences. The high discriminatory power of genotyping by FAFLP analysis revealed genetic microheterogeneity and differentiated otherwise "identical" M1 isolates as members of a clone complex.

Antigens, Bacterial↗
PubMed2000

The RofA binding site in Streptococcus pyogenes is utilized in multiple transcriptional pathways.

Understanding the regulation of adhesins defines a pathogenic bacterium's interaction with the local environment within the host. In certain strains of Streptococcus pyogenes, transcription of prtF, the gene which encodes the fibronectin-binding adhesin protein F, is activated by RofA under anaerobic conditions. RofA binds specifically to DNA in its target promoters and autoregulates its own expression. In this study, we have used DNase I protection assays to further investigate the interaction of RofA with its target promoters. In the region between rofA and the gene which encodes protein F (prtF), RofA binds to two distinct sites: a smaller site (17 bp) adjacent to the rofA promoter, and a larger site (40 bp) adjacent to the prtF promoter. Analysis of fusions to a novel reporter gene whose product consists of the fusion of the N-terminal secretion domain of protein F with the C-terminal enzymatic domain of the enterococcal alkaline phosphatase (PhoZ) revealed that the small RofA binding site had no direct role in control of prtF transcription but contributed to regulation of rofA. Comparison in several strains representing different patterns of prtF expression indicated that the larger site was required for activation of rofA and of prtF in all strains by both RofA-dependent and -independent pathways. Thus, it would appear that a common recognition sequence provides separate entries to a final common pathway in S. pyogenes virulence gene expression. The identification of multiple RofA-like proteins and promoters with RofA binding sites implies the existence of a widespread interacting regulatory network.

Adhesins, Bacterial↗
PubMed1993

A comparison of Streptococcus pyogenes (group A streptococcal) bacteremia at an urban and a suburban hospital. The importance of intravenous drug use.

BACKGROUND: There has been a recent resurgence of severe infections with Streptococcus pyogenes, including bacteremias and a toxic shock-like syndrome. The purpose of this study was to examine the influence of intravenous drug use on the incidence, clinical epidemiology, and severity of S pyogenes bacteremia. METHODS: We conducted a retrospective survey of medical records at a 500-bed tertiary care urban hospital and at a nearby 500-bed suburban university-affiliated hospital. All patients from each hospital with documented S pyogenes bacteremia from January 1, 1979, to December 31, 1989, were included. We examined demographic and clinical data from cases at the two institutions, serologic findings from a subset of isolates from the urban hospital, and factors associated with mortality from S pyogenes bacteremia by stepwise logistic regression analysis. RESULTS: Ninety-five cases of S pyogenes bacteremia were identified, with 65% (62 cases) occurring at the urban center. Intravenous drug use occurred more frequently at the urban center (P < .005); the injecting drug users were significantly younger than the non-drug-using population (P = .001). Infection with the human immunodeficiency virus occurred in a subset of the injecting drug users at the urban center. Cellulitis and cutaneous abscesses were the most common sources of bacteremia at both centers. During the study period, the numbers of S pyogenes bacteremias increased at the urban center (P = .007), accompanied by a significant increase in the proportion of infections associated with parenteral drug use (P = .003). There was no change in the prevalence of any T type throughout the study period and no clustering of T types among injecting drug users. The overall mortality was 23% (20/89). By logistic regression analysis, age older than 65 years (relative risk [RR], 14; 95% confidence interval [CI], 3.2 to 68) and the presence of the toxic shock-like syndrome (RR, 36; 95% CI, 2.2 to 600) were significantly associated with mortality due to S pyogenes bacteremia. CONCLUSIONS: Intravenous drug use accounted for an increase in cases of S pyogenes bacteremia at an inner-city hospital. However, advanced age and the toxic shock-like syndrome were the most important predictors of mortality.

Age Factors↗
PubMed1984

Cloning and expression in Escherichia coli of the streptolysin O determinant from Streptococcus pyogenes: characterization of the cloned streptolysin O determinant and demonstration of the absence of substantial homology with determinants of other thiol-activated toxins.

A gene bank of Streptococcus pyogenes Richards was constructed in Escherichia coli by using the bacteriophage replacement vector lambda L47.1, and hybrid phage expressing streptolysin O (SLO) were identified among the recombinants. DNA sequences encoding SLO were subcloned from an slo+ hybrid phage into a low-copy-number vector plasmid to yield an slo+ hybrid plasmid, pMK157. This plasmid contains 5.6 kilobase pairs of cloned streptococcal DNA sequences, is stable, and expresses SLO at easily detectable levels in E. coli. Transposon gamma delta insertion mutants and in vitro-generated deletion mutants of pMK157 were isolated and analyzed. This analysis showed that a single gene is sufficient for production of SLO in E. coli and allowed this slo gene to be mapped to within +/- 100 base pairs. Two forms of the slo gene product, with molecular weights of 68,000 and 61,000, were detected in E. coli minicells harboring slo+ plasmids and by immunoblotting of E. coli whole cells harboring slo+ plasmids. Southern blotting hybridization experiments with the cloned SLO DNA sequences as probes failed to demonstrate homology between the cloned SLO determinant and DNA isolated from bacteria expressing thiol-activated cytolysins related to SLO.

Bacterial Proteins↗
PubMed2004

Distribution and molecular analysis of mef(A)-containing elements in tetracycline-susceptible and -resistant Streptococcus pyogenes clinical isolates with efflux-mediated erythromycin resistance.

OBJECTIVES: To analyse the distribution and molecular features of mef(A)-containing elements in a large collection of different Streptococcus pyogenes clinical isolates with efflux-mediated erythromycin resistance. To further characterize a tet(O)-mef(A) element. METHODS: Gene detection was carried out by PCR using primers designed from established sequences or from sequences in this study. From a tet(O)-mef(A) element (approximately 60 kb), an 11 972 bp region including the tet(O) and mef(A) genes was sequenced. RESULTS: In the tetracycline-susceptible isolates (n =28), the mef(A) gene was contained in a regular Tn1207.1 transposon (7.2 kb), which was inserted into one of two previously described elements, Tn1207.3 (approximately 52 kb) or a 58.8 kb chimeric element, both flanked by the comEC gene. In the tetracycline-resistant isolates (n =61), all of which carried the tet(O) gene, the mef(A) gene was part of a variable Tn1207.1-related transposon inserted into unique elements which contained the tet(O) gene approximately 2.3 to 5.5 kb upstream of the mef(A) gene and were not flanked by the comEC gene. In the Tn1207.1-like transposon of these tet(O)-mef(A) elements, only msr(D) (orf5) and a modified orf6, in addition to mef(A), were detected by PCR in all isolates tested; while orf1 and orf2 were always undetectable, orf3, orf7 and orf8 were found in variable percentages. In an orf3-positive element, sequencing identified four new open reading frames downstream of the tet(O) gene, followed by three short sequences with homology to sequences of the pneumococcal mega element. CONCLUSIONS: The mef(A) gene is carried on different chromosomal genetic elements depending on whether the isolates are susceptible or resistant to tetracycline.

Anti-Bacterial Agents↗
PubMed2006

Activity of retapamulin against Streptococcus pyogenes and Staphylococcus aureus evaluated by agar dilution, microdilution, E-test, and disk diffusion methodologies.

The in vitro activity of retapamulin against 106 Staphylococcus aureus isolates and 109 Streptococcus pyogenes isolates was evaluated by the agar dilution, broth microdilution, E-test, and disk diffusion methodologies. Where possible, the tests were performed by using the CLSI methodology. The results of agar dilution, broth microdilution, and E-test (all with incubation in ambient air) for S. aureus yielded similar MICs, in the range of 0.03 to 0.25 microg/ml. These values corresponded to zone diameters between 25 and 33 mm by the use of a 2-microg retapamulin disk. Overall, 99% of the agar dilution results and 95% of E-test results for S. aureus were within +/-1 dilution of the microdilution results. For S. pyogenes, the MICs obtained by the agar and broth microdilution methods (both after incubation in ambient air) were in the range of 0.008 to 0.03 microg/ml, and E-test MICs (with incubation in ambient air) were 0.016 to 0.06 microg/ml. For S. pyogenes, 100% of the agar dilution MIC results were within +/-1 dilution of the broth microdilution results. E-test MICs (after incubation in ambient air) were within +/-1 and +/-2 dilutions of the broth microdilution results for 76% and 99% of the isolates, respectively. E-test MICs for S. pyogenes strains in CO(2) were up to 4 dilutions higher than those in ambient air. Therefore, it is recommended that when retapamulin MICs are determined by E-test, incubation be done in ambient air and not in CO(2), due to the adverse effect of CO(2) on the activity of this compound. Diffusion zones (with incubation in CO(2)) for S. pyogenes were 18 to 24 mm. Retapamulin MICs for all strains by all methods (with incubation in ambient air) were < or =0.25 microg/ml. These results demonstrate that S. pyogenes (including macrolide-resistant strains) and S. aureus (including methicillin-resistant and vancomycin-nonsusceptible strains) are inhibited by very low concentrations of retapamulin and that all four testing methods are satisfactory for use for susceptibility testing.

Anti-Bacterial Agents↗
PubMed1987

Investigations on the binding of erythrogenic toxin A of Streptococcus pyogenes on human peripheral blood lymphocytes. I. Light and electron microscopical demonstration of cell surface receptors using colloidal gold-labelled toxin.

Receptors for erythrogenic toxin A (ETA) of Streptococcus pyogenes (strain NY-5) were demonstrated on human peripheral blood lymphocytes by binding of ETA-gold conjugates to the cell surface. The specificity of the binding was proved in control experiments. The dark-red granules observed by light microscopy on unfixed cells were revealed by transmission electron microscopy to be patches of gold particles. By light microscopy on samples from 48 blood donors a mean value of 34 +/- 13% of ETA-receptor bearing lymphocytes was ascertained. The predominant part of the cells exhibited only a weak or moderate labelling. Transmission electron microscopy of prefixed cells revealed an attachment of single gold particles distributed over the whole cell surface. Counts of gold particles on serial sections yielded depending on prefixation values of 50-600 receptors/cell (1% glutaraldehyde) and 1000-7000 receptors/cell (0.26% glutaraldehyde), respectively. ETA cloned in Streptococcus sanguis as well as the toxoid of ETA exhibited a comparable binding as ETA (NY-5).

Bacterial Proteins↗
PubMed2000

Aerotolerance and peroxide resistance in peroxidase and PerR mutants of Streptococcus pyogenes.

Survival in aerobic conditions is critical to the pathogenicity of many bacteria. To investigate the means of aerotolerance and resistance to oxidative stress in the catalase-negative organism Streptococcus pyogenes, we used a genomics-based approach to identify and inactivate homologues of two peroxidase genes, encoding alkyl hydroperoxidase (ahpC) and glutathione peroxidase (gpoA). Single and double mutants survived as well as the wild type under aerobic conditions. However, they were more susceptible than the wild type to growth suppression by paraquat and cumene hydroperoxide. In addition, we show that S. pyogenes demonstrates an inducible peroxide resistance response when treated with sublethal doses of peroxide. This resistance response was intact in ahpC and gpoA mutants but not in mutants lacking PerR, a repressor of several genes including ahpC and catalase (katA) in Bacillus subtilis. Because our data indicate that these peroxidase genes are not essential for aerotolerance or induced resistance to peroxide stress in S. pyogenes, genes for a novel mechanism of managing peroxide stress may be regulated by PerR in streptococci.

Aerobiosis↗
PubMed2001

Mouse skin passage of a Streptococcus pyogenes Tn917 mutant of sagA/pel restores virulence, beta-hemolysis and sagA/pel expression without altering the position or sequence of the transposon.

BACKGROUND: Streptolysin S (SLS), the oxygen-stable hemolysin of Streptococcus pyogenes, has recently been shown to be encoded by the sagA/pel gene. Mutants lacking expression of this gene were less virulent in a dermonecrotic mouse infection model. Inactivation of the sagA/pel gene affect the expression of a variety of virulence factors in addition to the hemolysin. Insertion of a Tn917 transposon into the promoter region of the sagA/pel gene of S. pyogenes isolate CS101 eliminated expression of SLS, as well as decreased expression of the streptococcal pyrogenic exotoxin B, streptokinase and M protein. RESULTS: In this study a mouse skin air sac model was utilized to analyze the effect of biological pressures on expression of SLS and other sagA/pel regulated gene products. The insertion delayed the lethal effect of S. pyogenes in a mouse skin infection model. Despite this, bacteria could be cultured from the kidneys 72 hours post infection. These kidney-recovered isolates were beta-hemolytic despite the transposon being present in its original location and had equivalent virulence to the wild type isolate when re-injected into naive mice. Northern blot analysis of the kidney-recovered isolates confirmed that transcription of sagA/pel was restored; however the expression of all sagA/pel regulated genes was not restored to wild type levels. CONCLUSIONS: These results show that biological pressure present in the mouse can select for variants with altered expression of key virulence factor genes in S. pyogenes.

Animals↗
PubMed2004

Mouse skin passage of Streptococcus pyogenes results in increased streptokinase expression and activity.

The plasminogen activator streptokinase has been proposed to be a key component of a complex mechanism that promotes skin invasion by Streptococcus pyogenes. This study was designed to compare ska gene message and protein levels in wild-type M1 serotype isolate 1881 and a more invasive variant recovered from the spleen of a lethally infected mouse. M1 isolates selected for invasiveness demonstrated enhanced levels of active plasminogen activator activity in culture. This effect was due to a combination of increased expression of the ska gene and decreased expression of the speB gene. The speB gene product, SpeB, was found to efficiently degrade streptokinase in vitro.

Animals↗
PubMed1976

Streptococcus pyogenes preparation OK-432: immunoprophylactic and immunotherapeutic effects on the incidence of spontaneous leukemia in AKR mice.

An inactivated and lyophilized preparation of a low virulence strain (Su) of Streptococcus pyogenes (group A) was designated OK-432. When 2- and 5-month-old AKR mice were inoculated im with OK-432 twice weekly throughout their life-spans, spontaneous leukemias occurred later and at a lower incidence than in control groups. By virus neutralization and cytotoxicity tests and by immunoelectron microscopy, antibodies against virus and cell-surface antigens of transplanted AKR leukemia were not detectable in sera of nonleukemic mice of any group. Whereas sera from mice treated with OK-432 were the only positive for interferon, viremia was clearly demonstrated in control groups by reverse transcriptase assays of the plasma.

Animals↗
PubMed1981

[T-proteins of Streptococcus pyogenes. III. Communication: purification of T-proteins extracted with trypsin, pepsin and C-phage-associated lysin by means of immunochromatography (author's transl)].

T-proteins of Streptococcus pyogenes type 1 were extracted by enzymatic treatment of cells with trypsin, pepsin or C-phage-associated lysin and subsequently purified by ion exchange chromatography on DEAE cellulose as well as by immuno-adsorption on immobilized anti-T-type 1 antibodies. Immunochromatographical purified T1-proteins which were extracted by the different enzymes showed different properties in immuno-electrophoresis, SDS-electrophoresis and amino acid composition although a serological reaction of identity was found in Ouchterlony precipitation. Tryptic and peptic digestion was efficient for extraction of T protein while the extraction with C-phage-associated lysin was unsuitable for isolation of T-protein. The release of T-protein after treatment of cells with this lysin was very low and the preparation purified by this way exhibited cross-reaction with non-absorbed antisera of other types.

Bacterial Proteins↗
PubMed1992

Adherence of Streptococcus pyogenes M type 5 to pharyngeal and buccal cells of patients with rheumatic fever and rheumatic heart disease during a one-year follow-up.

In vitro adherence of Streptococcus pyogenes M type 5 to isolated pharyngeal and buccal epithelial cells was studied in patients with acute recurrent rheumatic fever (n = 21), chronic rheumatic heart disease (n = 33), streptococcal pharyngitis (n = 12), and in normal controls. Patients were investigated at admission and one, six and 12 months later. Streptococci adhered significantly more to the pharyngeal cells of patients with rheumatic fever and rheumatic heart disease than to the pharyngeal cells of controls. Adherence of streptococci to pharyngeal cells of patients with pharyngitis was not different from age-matched controls. The adherence of streptococci to the pharyngeal cells of patients with acute rheumatic fever fell during follow-up but even after one year remained significantly higher than in the control group. These findings suggest that host factor(s) controlling streptococcal adhesion and colonization at the pharyngeal mucosa may be important in the pathogenesis of acute rheumatic fever.

Acute Disease↗
PubMed1980

[T-proteins of Streptococcus pyogenes. II. Communication: Preparation of specific immunoadsorbents for isolation of anti-T-antibodies and investigations of the T4/24...pattern (author's transl)].

The T4-antigen(s) in Streptococcus pyogenes standard type strains of the T4/24...pattern was (were) investigated in regard to the uniformity or diversity of the antigen(s) in this T-complex. Tryptic T-extracts of types 4, 24, 26, 28, 29, 46, 48, 60 were purified by ion exchange chromatography on DEAE-cellulose. Anti-T4-antibodies were isolated by immunoadsorption chromatography on AH-sepharose linked T4-antigen. Purified T4-antigen showed in SDS-electrophoresis a similar multiple molecular size structure as T1-antigen described earlier. Comparative serological studies of T-antigens of types 4, 24, 29 and 46 revealed reactions of identity to anti-T4-antibodies in Ouchterlony tests. Extracts of types 26, 28, 48 and 60 did not precipitate with anti-T4-antibodies, but types 28 and 48 showed crossreaction to the relevant antisera (anti-T28 and anti-T48, resp.) obviously caused by traces of R-28 antigen in both antigen preparations. Strains of the types 4, 24, 29, 46, 48 and 60 were agglutinated by anti-T4-antibodies. The reaction could be inhibited by T4-antigen. The strains of type 26 and 28 used in our experiments did not contain T4-antigen. Agglutination as well as immunoprecipitation reactions with specific antibodies prepared by immunochromatography proved the existence of common T4-antigenic determinants in type 4, 24, 29, 46, 48 and 60.

Animals↗
PubMed2004

Streptococcus pneumoniae and Streptococcus pyogenes isolated from a paediatric population in Great Britain and Ireland: the in vitro activity of telithromcycin versus comparators.

OBJECTIVES: To investigate the antimicrobial susceptibility profiles of clinical isolates of Streptococcus pneumoniae and Streptococcus pyogenes, isolated from children within Great Britain and Ireland (Northern Ireland and Eire), with particular reference to the new oral ketolide telithromycin. To determine the distribution of macrolide resistance genes within the erythromycin resistant population. METHODS: MICs were determined using NCCLS microbroth dilution methodology and macrolide resistance mechanisms were investigated using PCR. RESULTS: Penicillin susceptibility was found to be 92.6% in S. pneumoniae isolates ( n=831; 3.7% intermediate, MIC 0.12-1 mg/l, 3.7% resistant, MIC >2.0 mg/l) and 100% in S. pyogenes isolates (n=1333) 8.8% of S. pneumoniae and 2.5% of S. pyogenes isolates demonstrated erythromycin-A resistance (EryA(R)). One hundred percent of S. pneumoniae and 99.8% of S. pyogenes isolates were susceptible to telithromycin (MIC<or=1.0 mg/l). Of the 73 EryA(R) S. pneumoniae isolates tested, 55 (75.3%) were mef (A) positive, 17 (23.3%) erm (B) positive and one isolate (1.4%) was positive for both mechanisms. Of the 34 isolates of EryA(R) S. pyogenes tested, 23 (67.6%) were erm (A) subclass erm (TR) positive, 4 (11.8%) erm (B) and 7 (20.6%) mef (A) positive. CONCLUSIONS: This paper presents baseline data on penicillin and macrolide resistance in S. pneumoniae and S. pyogenes isolates in the paediatric population of Great Britain and Ireland. Telithromycin, recently approved for the treatment of community acquired respiratory tract infections (CARTI) in patients over 12 years of age throughout the European community, demonstrated high in vitro activity against these pathogens, including EryA(R) strains.

Child↗
PubMed2000

Topological organization of the hyaluronan synthase from Streptococcus pyogenes.

Since we first reported (DeAngelis, P. L., Papaconstantinou, J., and Weigel, P. H. (1993) J. Biol. Chem. 268, 19181-19184) the cloning of the hyaluronan (HA) synthase from Streptococcus pyogenes (spHAS), numerous membrane-bound HA synthases have been discovered in both prokaryotes and eukaryotes. The HASs are unique among enzymes studied to date because they mediate 6-7 discrete functions in order to assemble a polysaccharide containing hetero-disaccharide units and simultaneously effect translocation of the growing HA chain through the plasma membrane. To understand how the relatively small spHAS performs these various functions, we investigated the topological organization of the protein utilizing fusion analysis with two reporter enzymes, alkaline phosphatase and beta-galactosidase, as well as several other approaches. From these studies, we conclude that the NH2 terminus and the COOH terminus, as well as the major portion of a large central domain are localized intracellularly. The first two predicted membrane domains were confirmed to be transmembrane domains and give rise to a very small extracellular loop that is inaccessible to proteases. Several regions of the large internal central domain appear to be associated with, but do not traverse, the membrane. Following the central domain, there are two additional transmembrane domains connected by a second small extracellular loop that also is inaccessible to proteases. The COOH-terminal approximately 25% of spHAS also contains a membrane domain that does not traverse the membrane and may contain extensive re-entrant loops or amphipathic helices. Numerous membrane associations of this latter COOH-terminal region and the central domain may be required to create a pore-like structure through which a growing HA chain can be extruded to the cell exterior. Based on the high degree of similarity among Class I HAS family members, these enzymes may have a similar topological organization for their spHAS-related domains.

Base Sequence↗