Related Experiment Video

Updated: Aug 17, 2026

Implementation of a Permeable Membrane Insert-based Infection System to Study the Effects of Secreted Bacterial Toxins on Mammalian Host Cells
09:25

Implementation of a Permeable Membrane Insert-based Infection System to Study the Effects of Secreted Bacterial Toxins on Mammalian Host Cells

Published on: August 19, 2016

Involvement of streptococcal mitogenic exotoxin Z in streptococcal toxic shock syndrome

Lily Yang1, Mark Thomas, Andrew Woodhouse

  • 1Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.

Journal of Clinical Microbiology
|July 8, 2005
PubMed

Insights

A novel Streptococcus pyogenes strain caused toxic shock syndrome (STSS) via a unique streptococcal mitogenic exotoxin Z (SMEZ-34) variant. This toxin

Area of Science:

  • Microbiology
  • Immunology
  • Toxicology

Background:

  • Streptococcal toxic shock syndrome (STSS) is a severe, life-threatening condition.
  • Streptococcus pyogenes is a common bacterial pathogen associated with STSS.
  • Mitogenic exotoxins are key virulence factors in STSS pathogenesis.

Observation:

  • A nonfatal case of STSS was linked to a Streptococcus pyogenes emm118 strain.
  • This strain produced a novel variant of streptococcal mitogenic exotoxin Z, designated SMEZ-34.
  • SMEZ-34 demonstrated significant mitogenic activity in vitro.

Findings:

  • The novel SMEZ-34 variant was identified as the primary mitogenic factor.
  • Patient serum analysis revealed seroconversion against SMEZ-34.
  • This suggests SMEZ-34 plays a crucial role in the host immune response during STSS.

Implications:

  • Understanding SMEZ-34's role could lead to new diagnostic or therapeutic strategies for STSS.
  • This finding expands knowledge of bacterial toxin diversity and their impact on disease.
  • Further research into SMEZ variants may elucidate specific mechanisms of STSS.

More Related Videos

Studying Oxidative Stress Caused by the Mitis Group Streptococci in Caenorhabditis elegans09:36

Studying Oxidative Stress Caused by the Mitis Group Streptococci in Caenorhabditis elegans

Published on: March 23, 2019

Related Concept Videos

Streptococcal Pharyngitis01:27

Streptococcal Pharyngitis

Streptococcal pharyngitis, commonly known as “strep throat,” is an acute infection of the oropharyngeal tissues caused by the Gram‑positive Group A Streptococcus (Streptococcus pyogenes). Transmission occurs primarily through respiratory droplets expelled during coughing, sneezing, or talking.Mechanisms of Host Entry and Immune EvasionUpon entering the host, S. pyogenes adheres to the mucosal epithelial cells of the pharynx via surface proteins, notably lipoteichoic acid and the antiphagocytic...
Staphylococcal Skin Infections01:29

Staphylococcal Skin Infections

Staphylococcus aureus is a Gram-positive coccus that resides harmlessly on the skin and mucous membranes of healthy individuals. When the skin barrier is breached, it can shift from a commensal to an opportunistic pathogen. This transition is facilitated by surface adhesins, such as clumping factor B and S. aureus surface protein G (SasG), which bind to structural proteins, including loricrin and cytokeratin, in the damaged epidermis. Protein A, another key factor, binds the Fc region of...
Diphtheria01:28

Diphtheria

Diphtheria is an acute, toxin-mediated infectious disease that primarily affects the upper respiratory tract. It is caused by Corynebacterium diphtheriae, a Gram-positive, pleomorphic rod that lacks spore-forming capability and exhibits a characteristic club-shaped morphology under microscopic examination. While C. diphtheriae can asymptomatically colonize mucosal surfaces, clinical disease manifests only when the bacterial strain is lysogenized by a specific β-corynephage. This phage...
Determinants of Bacterial Pathogenicity and Virulence01:20

Determinants of Bacterial Pathogenicity and Virulence

Pathogenic bacteria employ a variety of strategies to establish infections, including the secretion of extracellular enzymes that act as potent virulence factors. These enzymes facilitate bacterial colonization of host tissues and help evade immune surveillance. By targeting structural components of host tissues and interfering with immune mechanisms, these enzymes play a pivotal role in disease progression.Extracellular Enzymes Facilitating Tissue Invasion: Several bacterial pathogens secrete...
Bacterial Gastroenteritis01:18

Bacterial Gastroenteritis

Bacterial gastroenteritis, characterized by diarrhea, abdominal cramps, and vomiting, is often caused by ingestion of contaminated food or water and is frequently associated with pathogenic Escherichia coli strains. These microbes exploit two principal mechanisms to inflict disease.Shiga toxin–producing E. coli, also referred to as STEC—notably O157:H7—release Shiga toxins that target ribosomes, blocking protein synthesis. The B subunit of the toxin binds the host glycolipid receptor...
Acute Inflammation III: Local and Systemic Effects01:25

Acute Inflammation III: Local and Systemic Effects

Acute inflammation produces a coordinated set of local and systemic changes that limit injury, eliminate pathogens, and initiate repair. These responses arise within minutes of infection, trauma, or chemical insult and are driven by vascular alterations and leukocyte-derived mediators. When the stimulus resolves, the reaction typically abates within days.Local EffectsAt the site of injury, arteriolar vasodilation increases blood flow, resulting in redness and warmth. Simultaneously, increased...