pyogenes toxin

OBJECTIVE: Invasive group A streptococcus (iGAS) infections are associated with a high rate of morbidity and mortality. CNS involvement is rare, with iGAS accounting for only 0.2%-1% of all childhood bacterial meningitis. In 2022, a significant increase in scarlet fever and iGAS was reported globally with a displacement of serotype, causing a predominance of the emm1.0 subtype. Here, the authors report on iGAS-related suppurative intracranial complications requiring neurosurgical intervention and prolonged antibiotic therapy...

Streptococcus pyogenes can cause a wide variety of acute infections throughout the body of its human host. An underlying transcriptional regulatory network (TRN) is responsible for altering the physiological state of the bacterium to adapt to each unique host environment. Consequently, an in-depth understanding of the comprehensive dynamics of the S. pyogenes TRN could inform new therapeutic strategies. Here, we compiled 116 existing high-quality RNA sequencing data sets of invasive S. pyogenes serotype M1 and estimated the TRN structure in a top-down fashion by performing independent component analysis (ICA)...

Streptococcus pyogenes is an important human pathogen, commonly spread by airborne droplets but also by ingestion of contaminated food. Apart from causing infection, this pathogen produces 13 distinct types of streptococcal pyrogenic exotoxins (SPEs). The current method for detection cannot distinguish between the biologically active form of SPEs that has been reported to cause foodborne outbreaks and the inactivated toxin which poses no health risk. To measure the biological activity of SPE-C, one such toxin that was linked to foodborne outbreaks associated with milk and milk products, we developed a cell-based assay that can discern between biologically active and inactive SPE-C...

Streptococcus pyogenes genotype emm 1 is a successful, globally distributed epidemic clone that is regarded as inherently virulent. An emm 1 sublineage, M1UK , that produces increased levels of SpeA toxin was associated with increased scarlet fever and invasive infections in England in 2015/2016. Defined by 27 SNPs in the core genome, M1UK is now dominant in England. To more fully characterize M1UK , we undertook comparative transcriptomic and proteomic analyses of M1UK and contemporary non-M1UK emm 1 strains (M1global )...

An increasing number of isolations of Corynebacterium diphtheriae has been observed in recent years in the archipelago of New Caledonia. We aimed to analyze the clinical and microbiological features of samples with C. diphtheriae. All C. diphtheriae isolates identified in New Caledonia from May 2015 to May 2019 were included. For each case, a retrospective consultation of the patient files was conducted. Antimicrobial susceptibility phenotypes, tox gene and diphtheria toxin expression, biovar, and the genomic sequence were determined...

BACKGROUND: We describe a case of a toxic shock-like syndrome in a child, which was associated with Staphylococcus epidermidis instead of Staphylococcus aureus or Streptococcus pyogenes, the usual causes of toxic shock syndrome. CASE PRESENTATION: The patient was an 8-year-old boy who developed a toxic shock syndrome-like illness, including fever, hypotension, and rash. The Staphylococcus epidermidis isolate was cultured from urine, but this organism was unavailable for toxin testing...

A new variant of Streptococcus pyogenes serotype M1 (designated 'M1UK ') has been reported in the United Kingdom, linked with seasonal scarlet fever surges, marked increase in invasive infections, and exhibiting enhanced expression of the superantigen SpeA. The progenitor S. pyogenes 'M1global ' and M1UK clones can be differentiated by 27 SNPs and 4 indels, yet the mechanism for speA upregulation is unknown. Here we investigate the previously unappreciated expansion of M1UK in Australia, now isolated from the majority of serious infections caused by serotype M1 S...

Many species of pathogenic bacteria damage tissue cells by secreting toxins that form pores in plasma membranes. Here we show that glucocorticoids increase the intrinsic protection of tissue cells against pore-forming toxins. Dexamethasone protected several cell types against the cholesterol-dependent cytolysin, pyolysin, from Trueperella pyogenes. Dexamethasone treatment reduced pyolysin-induced leakage of potassium and lactate dehydrogenase, limited actin cytoskeleton alterations, reduced plasma membrane blebbing, and prevented cytolysis...

Mutation within the Streptococcus pyogenes ( Streptococcus group A; Strep A) covR/S regulatory system has been associated with a hypervirulent phenotype resulting from the upregulation of several virulence factors, including the pore-forming toxin, streptolysin O (SLO). In this study, we utilized a range of covR/S mutants, including M1T1 clonal strains (5448 and a covS mutant generated through mouse passage designated 5448AP), to investigate the contribution of SLO to the pathogenesis of covR/S mutant Strep A disease...

Severe bacterial or viral infections can induce a state of immune hyperactivation that can culminate in a potentially lethal cytokine storm. The classic example is toxic shock syndrome, a life-threatening complication of Staphylococcus aureus or Streptococcus pyogenes infection, which is driven by potent toxins known as superantigens (SAgs). SAgs are thought to promote immune evasion via the promiscuous activation of T cells, which subsequently become hyporesponsive, and act by cross-linking major histocompatibility complex class II molecules on antigen-presenting cells to particular β-chain variable (TRBV) regions of αβ T cell receptors (TCRs)...

Clostridium perfringens toxinotype E infections are rare in calves, and the development of intestinal lesions were commonly observed. In 2012, a 6-day-old calf in Japan exhibited swelling with emphysema on the right gluteal region, sudden paralysis of the hind limb and dysstasia. A pathological examination revealed myositis of the gluteal muscle and neuritis of the ischiatic nerve. C. perfringens type E strain CP118 was isolated from the affected muscle. However, the intestinal symptoms and lesions that commonly develop in type E infections in calves were not detected in the present case...

Immunogenic carrier proteins such as the non-toxic diphtheria toxin variant, cross-reacting material 197 (CRM197), are widely used in subunit vaccine formulations to boost immunogenicity of chemically conjugated antigens. Conjugate vaccines are inherently expensive due to laborious manufacturing steps. Here, this work develops a particulate vaccine platform based on using engineered Escherichia coli to assemble CRM197-antigen fusion proteins into discrete submicron-sized particles. This approach enables precise loading of diverse antigens and epitopes enhancing their immunogenicity...

Group A Streptococcus (GAS, Streptococcus pyogenes ) is a Gram-positive human pathogen that employs several secreted and surface-bound virulence factors to manipulate its environment, allowing it to cause a variety of disease outcomes. One such virulence factor is Streptolysin S (SLS), a ribosomally-produced peptide toxin that undergoes extensive post-translational modifications. The activity of SLS has been studied for over 100 years owing to its rapid and potent ability to lyse red blood cells, and the toxin has been shown to play a major role in GAS virulence in vivo ...

Streptococcus pyogenes ( S. pyogenes ) bacteria cause almost all primary skin infections in humans. Bee venom (BV) and melittin (Mel) have multiple effects, including antibacterial and anti-inflammatory activities. This study aims to demonstrate their effects on bacterial mouse skin infection using S. pyogenes . The dorsal skin was tape-stripped, then S. pyogenes was topically applied. BV or Mel were topically applied to the lesion. The tissues were stained with hematoxylin and eosin, while immunohistochemical staining was performed with anti-neutrophil...

Pyolysin (PLO) is secreted by Trueperella pyogenes as a water-soluble monomer after forming transmembrane β-barrel channels in the cell membrane by binding cholesterol. Two significantly conserved residues at domain 1 of PLO are mutated, which provides novel evidence of a relationship between conformational change and interaction with the cell membrane and uncovers the pore formation mechanism of the cholesterol-dependent cytolysin (CDC) family. Moreover, PLO is a special member of the CDCs, which the percentage of sequence identities between PLO and other CDC members is from 31% to 45%, while others are usually from 40% to 70%...

OBJECTIVE: An opportunistic pathogen, Trueperella pyogenes can infect cattle, buffalo, pig, goat, cat, dog, forest musk deer, etc., affecting various organs. The aim of this study was to identify the multidrug resistance genomic islands of T. pyogenes genomes available in NCBI database and also in the recently isolated strain TN_CUL_2020. METHODS: The strain TN_CUL_2020 isolated from swine lung abscess was sequenced by Illumina platform and all the available T. pyogenes genome in NCBI database was retrieved for the comparative analysis...

Necrotizing soft tissue infections caused by Streptococcus pyogenes (group A streptococcus [GAS]) are characterized by rapid and extensive necrosis of fascia and muscle. Molecular epidemiological studies have demonstrated a positive correlation between GAS isolates that cause invasive infections and the production of S. pyogenes NAD+-glycohydrolase (SPN), an NADase secreted by GAS, but the effect of SPN on muscle cells has not been described. Thus, using standard βNAD+ and ATP quantification assays, we investigated the effects of SPN on cultured human skeletal muscle cell (SkMC) βNAD+ and ATP with and without streptolysin O (SLO)-a secreted cholesterol-dependent cytolysin known to act synergistically with SPN...

Group A streptococcus (GAS, Streptococcus pyogenes ) is a common pathogen that can cause a variety of human diseases. Streptolysin O (SLO) is an exotoxin produced by GAS. It is a pore-forming toxin (PFT) that exhibits high in vivo toxicity. SLO enables GAS to evade phagocytosis and clearance by neutrophils, induces eukaryotic cell lysis, and activates inflammatory bodies. Luteolin is a natural compound that is produced by a wide range of plant species, and recent studies have shown that luteolin can inhibit the growth and alter the morphological of GAS...

Nonhealing diabetic foot ulcers (DFU), a major complication of diabetes, are associated with high morbidity and mortality despite current standard of care. Since Staphylococcus aureus is the most common pathogen isolated from nonhealing and infected DFU, we hypothesized that S. aureus virulence factors would damage tissue, promote immune evasion and alter the microbiome, leading to bacterial persistence and delayed wound healing. In a diabetic mouse polymicrobial wound model with S. aureus, Pseudomonas aeruginosa, and Streptococcus pyogenes, we report a rapid bacterial proliferation, prolonged pro-inflammatory response and large necrotic lesions unclosed for up to 40 days...

INTRODUCTION: The objective of this study is to characterize Streptococcus pyogenes isolates with a mucoid phenotype and to compare them with non-mucoid isolates obtained between April and August 2016. MATERIAL AND METHODS: Identification and antimicrobial susceptibility were performed in all isolates. The emm type and exotoxin genes speA, speB, speC, speF, speG, speH, speJ, speZ and ssa were analyzed. Clinical and demographic data were collected. RESULTS: From 96 isolates analyzed, 47% had a mucoid phenotype and 95...