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PubMed2005

Utilisation of macrolides and the development of Streptococcus pyogenes resistance to erythromycin.

OBJECTIVES: The aim of the study was to evaluate the relationship between the development of the resistance of Streptococcus pyogenes strains to erythromycin and the utilisation of macrolides in the Olomouc region, Czech Republic. METHOD: During the period 1997-2001, data for utilisation of macrolides was obtained from the database of the regional General Health Insurance Company and expressed indefined daily doses per 1,000 patients per day. S. pyogenes strains were isolated from community patients suffering from acute bacterial tonsillitis. Their susceptibility to antibiotics was assessed by the disk diffusion method. RESULTS: Utilisation of macrolides increased by 13% in the period 1997-2001; their utilisation represented 11.40% of total antibiotic prescription in 1997 and 15.48% in 2001. Occurrence of erythromycin-resistant S. pyogenes strains increased significantly from 14% in 1997 to 32% in the year 2001 (P < 0.01). In 2000, macrolides consumption decreased non-significantly, but with no concomitant decrease in erythromycin-resistant S. pyogenes strains occurrence. Absolute susceptibility of S. pyogenes, the most important bacterial pathogen in community-acquired bacterial tonsillitis, to penicillin contrasts with increasing macrolide resistance. CONCLUSIONS: The study documents the influence of increased utilisation of macrolides on bacterial resistance. Penicillin should be a first-choice antibiotic in acute bacterial tornsillitis; macrolides should only be reserved for patients allergic to penicillins.

Anti-Bacterial Agents↗

PubMed1995

[Distribution of the genes of streptococcal pyrogenic exotoxin among clinical isolates of Streptococcus pyogenes from the pharynx].

The distribution of the genes of streptococcal pyrogenic exotoxin (speA, B and C) among the 400 clinical isolates of Streptococcus pyogenes from Japanese pharnyx was detected by the PCR method (Nihonrinsho 50: 326, 1992). Sixty, 399 and 303 isolates were positive for the speA, B and C genes, respectively. However, only one isolate had none of these genes. Several isolates possessed two or three genes, i.e., both speB & C, speA & B or speA, B & C were found in 258, 30 and 30 isolates, respectively. No isolate possessing both speA & C without speB was found in this study. We concluded that the PCR method is much more useful for the epidemiological study on streptococcal pyrogenic exotoxins (SPE) of S. pyogenes isolates because of specificity, rapidity and sensitivity of this method compared with the conventional SPE identification method.

Exotoxins↗

PubMed2001

Use of surface-enhanced laser desorption ionization protein chip system to analyze streptococcal exotoxin B activity secreted by Streptococcus pyogenes.

Ciphergen surface-enhanced laser desorption ionization (SELDI) protein chip technology was used to analyze the secretion and autoactivation of the Streptococcus pyogenes cysteine protease SpeB. This method allowed rapid identification of both the zymogen form of the protein Mr approximately 41,000 and the fully active enzyme Mr approximately 28,500. SpeB production in culture supernatants was demonstrated to be growth-phase regulated and SpeB positive and negative variants of a blood passaged S. pyogenes isolate could readily be distinguished. In kinetic studies of the autoactivation of the zymogen form of SpeB, the sequential generation of four intermediates was detected before the accumulation of the fully active enzyme. The methods described enabled enhanced speed, use of lower sample volumes and concentrations, and a more complete molecular characterization of SpeB than allowed by existing methods of analysis using SDS-PAGE and Western immunoblotting.

Bacterial Proteins↗

PubMed1995

Insertional inactivation of virR in Streptococcus pyogenes M49 demonstrates that VirR functions as a positive regulator of ScpA, FcRA, OF, and M protein.

Several reports have shown that Streptococcus pyogenes strains which produce opacity factor (OF+) have diverged significantly from OF- serotypes. This study questions whether several surface proteins of an OF+ culture are regulated by the positive regulatory protein VirR, in a manner similar to OF- strains. Interruption of the virR region of an OF+ S. pyogenes (strain CS101, M type 49) was performed using a temperature-sensitive plasmid containing a fragment of virR. Interruption of the virR region produced cultures with undetectable amounts of M49 and ScpA proteins, and reduced the yield of FcRA protein. In addition, mutants had a significant reduction in detectable opacity factor. These results suggest that virR functions as a positive regulator of a variety of surface proteins in OF+ strains.

Antigens, Bacterial↗

PubMed1981

Mutational loss of susceptibility to mutacin GS-5 in Streptococcus pyogenes: surface protein in a tolerant variant.

A variant (S4340) nonsusceptible to mutacin GS-5 was previously obtained from a strain of Streptococcus pyogenes susceptible to this bacteriocin. The variant was found to adsorb as much bacteriocin as parent cells and exhibit similar susceptibility to seven antibiotics and two detergents. Electrophoretic analysis of protein dissociated from mutant cells by brief sonication revealed the presence of a 74,000-dalton polypeptide not discernible in profiles obtained from susceptible parent cells. The precise role of this tolerance-associated marker remains to be determined. The protein does not appear to be an exported product transiently associated with the cell envelope.

Anti-Bacterial Agents↗

PubMed1987

Roxithromycin in the therapy of Streptococcus pyogenes throat infections.

Roxithromycin in two dosage regimens was compared with erythromycin in the therapy of 227 patients with throat infectious due to Streptococcus pyogenes. All three groups had the same clinical efficacy but roxithromycin 300 mg daily was less effective than erythromycin 500 mg qds in eradicating S. pyogenes while there were less antibiotic-related side effects with roxithromycin 150 mg bd than with erythromycin.

Adolescent↗

PubMed2004

Evaluation of the degree of susceptibility of Streptococcus pyogenes erythromycin-resistant strains to rokitamycin (a 16-membered macrolide) using the Epsilometer test.

Routine hospital screening of the resistance of Streptococcus pyogenes to macrolides is usually done using the erythromycin, clarithromycin or azithromycin disk diffusion technique. When a strain is found to be resistant to one of these macrolides, it is generally assumed to be resistant to the whole class. However this approach gives only partial qualitative information because S. pyogenes strains with inducible and M phenotype resistance are still susceptible to 16-membered ring macrolides such as rokitamycin. Seventy-four erythromycin-resistant (22 inducible and 52 M phenotype) strains of S. pyogenes were tested for their susceptibility to rokitamycin and clindamycin (control) by means of the agar disk diffusion test and the results were compared with those obtained using the Epsilometer test, a quantitative technique for measuring bacterial susceptibility and minimal inhibitory concentrations (MIC). Epsilometer testing of erythromycin in comparison with rokitamycin is useful for measuring the real degree of susceptibility of macrolide-resistant strains quickly and simply. This is important because strains with the same disk diffusion diameter do not necessarily have the same MIC, but a scattered distribution of susceptibility.

Anti-Bacterial Agents↗

PubMedDate not supplied

Introduction of the emm6 gene into an emm-deleted strain of Streptococcus pyogenes restores its ability to resist phagocytosis.

To complete the formal proof that the M protein functions to protect the group A streptococcus from phagocytosis and to lay the groundwork for the molecular genetic dissection of this major virulence factor, we have reintroduced a wild-type allele of the M protein gene (emm) into the chromosome of a strain from which it had previously been deleted. For this purpose, we used homologous recombination with an engineered plasmid that was introduced into the Streptococcus pyogenes chromosome by an electroporation technique that we developed. The plasmid pJRS120E was constructed in Escherichia coli and contains the structural gene for the antiphagocytic M6 protein (emm6) of S. pyogenes JRS4 and a selectable marker (ermAM) between the chromosomal regions that flank emm6 in S. pyogenes. This plasmid was introduced into S. pyogenes strain JRS75, a strain that is not resistant to phagocytosis as a result of the allelic replacement of the emm6 gene by a kanamycin resistance gene (aphA3). DNA hybridization analysis indicated that in erythromycin-resistant strain JRS115, homologous recombination resulted in the replacement of the aphA3 gene of JRS75 with the introduced emm6 allele. Strain JRS115 produces approximately the same amount of M6 as does the parental emm6+ strain JRS4, as assayed by Western blot analysis, and is resistant to phagocytosis.

Alleles↗

PubMed2001

Complementation of a speA negative Streptococcus pyogenes with speA: effects on virulence and production of streptococcal pyrogenic exotoxin A.

We have shown previously that an isogenic SPEA-negative Streptococcus pyogenes strain did not attenuate virulence in a murine model of necrotizing fasciitis. The aim of this study was to confirm that streptococcal pyrogenic exotoxin A (SPEA) is not crucial for streptococcal invasiveness in murine invasive infection. The SPEA-negative S. pyogenes (H326) was complemented with speA extra-chromosomally to create strain H361 which produced 2.2-fold more SPEA compared with the parental speA(+)wild-type (H305). The growth phase-regulated expression of SPEA in vitro was unaffected in this strain. Complementation with speA resulted in reduced virulence and bacterial counts in invasive murine infection. SPEA production was quantitated from muscle tissue of infected mice. However, H361 did not produce more SPEA than H305 in vivo. We conclude that SPEA does not play a key role in invasive murine streptococcal infection.

Animals↗

PubMed1981

Factors affecting polysaccharide storage in group A Streptococcus pyogenes in non-proliferating cell suspensions.

Optimal conditions for intracellular polysaccharide (IPS) storage by non-proliferating suspensions of group A Streptococcus pyogenes are described. Concentrations of yeast extract and acid-hydrolysed casein which did not support measureable growth prevented bacterial death during storage. For optimal storage, high concentrations of maltose were required to antagonize the inhibitory effect of medium glucose released by intracellular amylomaltase activity. Stabilization of cell washing solutions with 0.5 M sucrose and the minimal storage medium with 8.0% w/v polyethylene glycol MW 6,000 was required for optimal culture viability and IPS storage. The stabilization effect prevented loss of small purine or pyrimidine-containing compounds required for IPS storage as indicated by culture water-shock treatment.

Culture Media↗

PubMed1998

Protein F, a fibronectin-binding protein of Streptococcus pyogenes, also binds human fibrinogen: isolation of the protein and mapping of the binding region.

During screening of a gene library of Streptococcus pyogenes type M15 for fibrinogen-binding material, a protein of approximately 100 kDa, encoded outside the vir region, was found. DNA sequencing revealed this component to be identical to protein F, a fibronectin-binding protein. Isolation of the recombinant protein, termed F15, was performed by the use of fibrinogen affinity chromatography. The affinity constant (Ka) of protein F15 for fibrinogen, 1.25 x 10(7) mol-1, was lower than that for fibronectin, 1.8 x 10(8) mol-1. The fibrinogen-binding domain was located in the N-terminal part of the molecule, while the fibronectin-binding domains, as previously determined, were in the C-terminal portion of protein F. To examine the amino acid sequence heterogeneity of protein F, the 5' part of the prtF gene, corresponding to the N-terminal variable region of the protein, was amplified by PCR from 12 strains of S. pyogenes belonging to six different M-types. Alignment of these nucleotide sequences indicated that the 5' portion of the prtF gene had probably undergone a number of intragenic recombination and horizontal gene transfer events, allowing a pattern of structural diversity of protein F observed earlier for some other streptococcal virulence factors. There was no strict correlation between M-type and nucleotide sequence of the variable region of the prtF gene and, compared to streptococcal M protein, the overall variation observed for protein F appeared more limited.

Adhesins, Bacterial↗

PubMed1997

Bacteriophage T12 of Streptococcus pyogenes integrates into the gene encoding a serine tRNA.

The region of temperate bacteriophage T12 responsible for integration into the chromosome of Streptococcus pyogenes has been identified. The integrase gene (int) and the phage attachment site (attP) are found immediately upstream of the gene for speA, the latter of which is known to be responsible for the production of erythrogenic toxin A (also known as pyrogenic exotoxin A). The integrase gene has a coding capacity for a protein of 41457 Da, and the C-terminus of the deduced protein is similar to other conserved C-terminal regions typical of phage integrases. Upstream of int is a second open reading frame, which is capable of encoding an acidic protein of 72 amino acids (8744 Da); the position of this region in relation to int suggests it to be the phage excisionase gene (xis). The arms flanking the integrated prophage (attL and attR) were identified, allowing determination of the sequences of the phage (attP) and bacterial (attB) attachment sites. A fragment containing the integrase gene and attP was cloned into a streptococcal suicide vector; when introduced into S. pyogenes by electrotransformation, this plasmid stably integrated into the bacterial chromosome at attB. The insertion site for the phage into the S. pyogenes chromosome was found to be in the anticodon loop of a putative type II gene for a serine tRNA. attP and attB share a region of identity that is 96 bp in length; this region of identity corresponds to the 3' end of the tRNA gene such that the coding sequence remains intact after integration of the prophage. The symmetry of the core region of att may set this region apart from previously described phage attachment sites (Campbell, 1992), and may play a role in the biology of this medically important bacteriophage.

Amino Acid Sequence↗

PubMed1999

Bactericidal/permeability-increasing protein inhibits growth of a strain of Acholeplasma laidlawii and L forms of the gram-positive bacteria Staphylococcus aureus and Streptococcus pyogenes.

Bactericidal/permeability-increasing protein (BPI) inhibited growth of cell wall-deficient Acholeplasma laidlawii and L forms of certain strains of Staphylococcus aureus and Streptococcus pyogenes. However, the same strains of S. aureus and S. pyogenes with intact cell walls were not susceptible to the growth-inhibitory effects of BPI.

Acholeplasma laidlawii↗

PubMed1972

Comparative electrophoretic and amino acid analyses of isolated membranes from Streptococcus pyogenes and stabilized L-form.

Major quantitative, but not qualitative, differences in the various species of proteins in purified membranes from Streptococcus pyogenes and its stabilized L-form have been demonstrated by acidic and alkaline disc gel electrophoresis with and without urea. The fact that no significant differences in the amino acid content or composition between these two membranes could be demonstrated emphasizes that these results are probably due to changes in the relative amounts of the various species of proteins in this subcellular component. The possibility of these protein changes in the L-form membrane being related to its inability to synthesize a rigid cell wall is discussed. Finally, phage-associated lysin, routinely used for removal of the group A streptococcal cell wall, does not appear to affect the protein profile or amino acid composition of the membrane either metabolically or nonmetabolically.

Amino Acids↗

PubMed2003

Novel genomic rearrangement that affects expression of the Streptococcus pyogenes streptolysin O (slo) gene.

A RecA-independent chromosomal rearrangement in the upstream region of the streptolysin O (slo) gene of Streptococcus pyogenes which affects slo expression was identified. PCR analysis was used to demonstrate that this kind of rearrangement was found in several strains of different lineages. Chromosomal loci involved in the recombination were found to be 746 kb apart on the 1.85-Mb-long chromosome. The primary structure of the splicing region, the reproducibility of the rearrangement, and the fact that reconstructed recombinant molecules fused to erm and lacZ reporter genes affected their expression indicate that this event is not accidental but may play a role in the expression of the slo gene. In addition, the product of the recombining DNAs, including the splicing site, does not follow any example of a known recombination mechanism. The implications of this rearrangement for slo expression are discussed.

Bacterial Proteins↗

PubMed1996

Substitution of cysteine 192 in a highly conserved Streptococcus pyogenes extracellular cysteine protease (interleukin 1beta convertase) alters proteolytic activity and ablates zymogen processing.

Virtually all strains of the human pathogenic bacterium Streptococcus pyogenes express a highly conserved extracellular cysteine protease. The protein is made as an inactive zymogen of 40,000 Da and undergoes autocatalytic truncation to result in a 28,000-Da active protease. Numerous independent lines of investigation suggest that this enzyme participates in one or more phases of host-parasite interaction, such as inflammation and soft tissue invasion. Replacement of the single cysteine residue (C-192) with serine (C192S mutation) resulted in loss of detectable proteolytic activity against bovine casein, human fibronectin, and the low-molecular-weight synthetic substrate 7-amino-4-trifluoromethyl coumarin. The C192S mutant molecule does not undergo autocatalytic processing of zymogen to mature form. Taken together, these data support the hypothesis that C-192 participates in active-site formation and enzyme catalysis.

Animals↗

PubMed1997

Mitogenic factor secreted by Streptococcus pyogenes is a heat-stable nuclease requiring His122 for activity.

The gene encoding a mitogenic factor, termed MF, was cloned from Streptococcus pyogenes and the recombinant MF was overexpressed in Escherichia coli. Both the natural and recombinant MF had heat-resistant nuclease activity. The nuclease activity of MF was characterized using the recombinant protein. MF showed endonuclease activity, digesting ssDNA, dsDNA and tRNA. The optimal pH for the DNase activity of MF was 9.5. The DNase activity was enhanced approximately tenfold by the simultaneous presence of two divalent cations, Mg2+ and Ca2+, compared to either alone and was inhibited by EDTA or NaCl. The heat stability of MF was biphasic; the DNase activity was heat-stable from 0 to 50 degrees C over 80 degrees C but very unstable at around 60 degrees C. DNA digested by MF possessed 5'-phosphorylated and 3'-hydroxylated termini, identical to those obtained by digestion of DNA by pancreatic deoxyribonuclease I. A mutant clone revealed that His122 was a residue essential to the nuclease activity.

Amino Acid Sequence↗

PubMed1999

Molecular typing of erythromycin-resistant streptococcus pyogenes strains with the M phenotype isolated in Italy.

To assess the spread of the new M phenotype, various erythromycin-resistant Streptococcus pyogenes strains from three Italian cities (Verona, Monza, Florence) were characterised. Each strain was analysed for the presence of genes ermAM and mefA, for the ability to accumulate radioactive erythromycin in the absence of sodium arsenate, for the protein T serological type, and for the DNA macrorestriction profile identified by means of pulsed-field gel electrophoresis. In a number of strains, the presence of the inducible ermAM gene was demonstrated; all these strains were negative in the efflux-pump detection assay, did not possess the mefA gene, and had similar restriction profiles. The strains with the efflux mechanism and mefA gene belonged to different serotypes. Of these, only one serotype, T4, was isolated in all three cities. The restriction profile analysis with SmaI and SfiI revealed a very close correlation between strains with the same serotype.

Anti-Bacterial Agents↗