Related Experiment Video

Updated: Mar 30, 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

11.5K

Description of the Pathogenic Features of Streptococcus pyogenes Isolates from Invasive and Non-Invasive Diseases in

Masakado Matsumoto1, Kazuhiro Yamada, Masahiro Suzuki

  • 1Department of Microbiology and Medical Zoology, Aichi Prefectural Institute of Public Health.

Japanese Journal of Infectious Diseases
|November 17, 2015
PubMed

Insights

Hypervirulent Streptococcus pyogenes strains, particularly emm1 genotype, were identified in Aichi, Japan, potentially explaining the 2011 rise in streptococcal toxic shock syndrome (STSS). These strains possess specific genetic mutations affecting virulence factor production.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Genetics

Background:

  • Streptococcal toxic shock syndrome (STSS) prevalence increased suddenly in Aichi Prefecture, Japan, during 2011.
  • Understanding the microbial factors driving this increase is crucial for public health.
  • Streptococcus pyogenes is a significant human pathogen responsible for various infections.

Purpose of the Study:

  • To investigate the characteristics of Streptococcus pyogenes isolates from invasive and non-invasive diseases in Aichi Prefecture between 2003 and 2012.
  • To determine if specific hypervirulent strains of Streptococcus pyogenes contributed to the observed increase in STSS.
  • To elucidate the genetic and phenotypic traits of these potentially hypervirulent strains.

Main Methods:

  • Identification and characterization of Streptococcus pyogenes isolates from patient samples.
  • Genotyping of isolates, focusing on the emm genotype and mutations in covR/S genes.
  • Analysis of virulence factor gene expression and protein production, including streptococcal exotoxin B, streptococcal exotoxin A, streptococcal DNase, NAD-glycohydrolase, and streptolysin O.

Main Results:

  • Hypervirulent Streptococcus pyogenes strains, predominantly emm1 genotype, were identified in both invasive (27 isolates) and non-invasive (420 isolates) disease cases.
  • These hypervirulent strains exhibited mutations in covR/S genes, leading to the absence of streptococcal exotoxin B and production of key virulence factors (streptococcal exotoxin A, streptococcal DNase, NAD-glycohydrolase, streptolysin O).
  • Hypervirulent-like strains lacking the sda1 gene and a non-emm1 strain with similar phenotypic and genetic traits to hypervirulent emm1 strains were also identified, particularly in 2011.

Conclusions:

  • Hypervirulent and hypervirulent-like Streptococcus pyogenes strains likely played a role in the 2011 surge of STSS in Aichi.
  • The genetic makeup of these strains, including covR/S mutations and specific virulence factor production, contributes to their hypervirulence.
  • These findings highlight the importance of molecular surveillance for understanding and controlling outbreaks of invasive streptococcal diseases.

More Related Videos

Invasion of Human Cells by a Bacterial Pathogen07:15

Invasion of Human Cells by a Bacterial Pathogen

Published on: March 21, 2011

35.5K
Visualization of Streptococcus pneumoniae within Cardiac Microlesions and Subsequent Cardiac Remodeling08:25

Visualization of Streptococcus pneumoniae within Cardiac Microlesions and Subsequent Cardiac Remodeling

Published on: April 7, 2015

9.6K

Related Concept Videos

Bacterial Phylum Spirochaetes01:30

Bacterial Phylum Spirochaetes

Spirochetes, unique bacteria in the phylum Spirochaetes, are gram-negative, motile, tightly coiled, slender, and flexible. They inhabit aquatic sediments and animals, with some causing diseases like syphilis. Spirochetes are classified into eight genera based on habitat, pathogenicity, phylogeny, and characteristics.Their distinctive motility arises from endoflagella, located within the cell’s periplasm. These endoflagella anchor at the cell poles and extend along the cell length, encased...
1.2K
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...
62
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...
32
Endocarditis II: Clinical Features of Infective Endocarditis01:25

Endocarditis II: Clinical Features of Infective Endocarditis

Endocarditis can present various clinical features depending on the causative organism and the patient's underlying health conditions. Initially, the clinical features of infective endocarditis develop gradually, presenting with nonspecific symptoms that can be easily mistaken for other illnesses.General SymptomsEarly symptoms of infective endocarditis are fever, chills, weakness, malaise, fatigue, and weight loss. These symptoms reflect the systemic nature of the infection and the body's...
775
Atypical Pneumonia01:14

Atypical Pneumonia

Atypical pneumonia, often caused by Mycoplasma pneumoniae, is a form of pulmonary infection that differs from the classical presentation of bacterial pneumonia in both its cause and clinical symptoms. Mycoplasma pneumoniae is a pleomorphic bacterium notable for its lack of a rigid cell wall. This structural characteristic imparts resistance to beta-lactam antibiotics and significantly influences the bacterium’s behavior within the human host.Other pathogens responsible for the disease...
38
Factors Affecting the Risk of Infection01:26

Factors Affecting the Risk of Infection

The hosts' susceptibility to infection depends on several factors. The integrity of the skin and mucous membranes helps protect the body against microbial attacks. When the skin is altered, the chance of infection, limb loss, and even death increases.
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin...
14.6K