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Updated: May 29, 2026
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
Streptococcus pyogenes bacteraemia, emm types and superantigen profiles
S Rantala1, S Vähäkuopus, T Siljander
1Department of Internal Medicine, Tampere University Hospital, P.O. Box 2000, 33521, Tampere, Finland. sari.rantala@uta.fi
Summary
This study analyzed 87 invasive Streptococcus pyogenes (group A streptococcal) isolates in Finland, finding no link between emm types or superantigen profiles and disease severity. A potential vaccine showed limited coverage for these invasive strains.
Area of Science:
- Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Group A Streptococcus (GAS), or Streptococcus pyogenes, causes invasive infections.
- Understanding molecular characteristics like emm types and superantigen profiles is crucial for tracking and managing GAS epidemiology.
- Previous studies have explored associations between GAS virulence factors and clinical outcomes.
Purpose of the Study:
- To investigate the emm types and superantigen profiles of bacteraemic GAS isolates.
- To determine if molecular characteristics correlate with clinical presentations of invasive disease.
- To assess the potential coverage of a 26-valent GAS vaccine against local isolates.
Main Methods:
- Population-based study of 87 bacteraemic GAS isolates from adult patients in Finland (1995-2004).
- emm typing and genotyping for superantigen (SAg) profiles.
- Analysis of epidemiological and clinical data alongside microbiological characterization.
Main Results:
- 18 different emm types were identified, with emm1, emm28, and emm81 being the most common (52%).
- No significant association was found between emm type and clinical features (underlying diseases, manifestations, case fatality).
- speA and speC genes were present in 20% and 30% of strains, respectively, with no link to disease manifestation. A 26-valent vaccine would cover only 62% of isolates.
Conclusions:
- emm type and superantigen profiles of bacteraemic GAS isolates in this Finnish population showed variability but no clear association with clinical disease presentation or severity.
- The identified emm types and SAg profiles suggest limited efficacy for the evaluated 26-valent GAS vaccine in this region during the study period.
- Further research is needed to understand the complex interplay between GAS molecular epidemiology and invasive disease outcomes.
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