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Published on: September 11, 2020

Emergence of a novel macrolide-resistant Streptococcus pyogenes emm53 strain

L Strakova1, J Motlova, V Jakubu

  • 1National Reference Laboratory (NRL) for Streptococci and Enterococci, National Institute of Public Health, Prague, Czech Republic. lenka.strakova@szu.cz

Clinical Microbiology and Infection : the Official Publication of the European Society of Clinical Microbiology and Infectious Diseases
|March 16, 2007
PubMed

Insights

A specific clone of erythromycin-resistant group A Streptococcus (GAS) was prevalent in the Czech Republic in 2003. This clone, identified as emm53/ST340, showed distinct genetic characteristics compared to other GAS strains.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Molecular Epidemiology

Background:

  • Group A Streptococcus (GAS) is a significant human pathogen.
  • Erythromycin resistance in GAS is an emerging public health concern.
  • Specific GAS clones can dominate and cause invasive infections.

Purpose of the Study:

  • To characterize an unusual emm53, T-28/T-non-typeable, iMLS(B) phenotype clone of GAS.
  • To investigate the clonal diversity and genetic relatedness of invasive erythromycin-resistant GAS isolates in the Czech Republic.
  • To trace the potential evolutionary history of the dominant emm53/ST340 clone.

Main Methods:

  • Analysis of invasive erythromycin-resistant GAS isolates from the Czech Republic (2001-2004).
  • Pulsed-field gel electrophoresis (PFGE) for clonal analysis.
  • Multilocus sequence typing (MLST) to determine sequence types (STs).

Main Results:

  • A specific emm53/ST340 clone constituted 28.6% of invasive erythromycin-resistant GAS isolates in 2003.
  • All emm53 isolates shared identical PFGE patterns, irrespective of invasiveness or tetracycline resistance.
  • The emm53/ST340 isolates showed significant genetic divergence from the original Lancefield emm53/ST11 isolate.

Conclusions:

  • The emm53/ST340 clone represents a distinct and successful lineage of invasive erythromycin-resistant GAS.
  • This clone has undergone genetic changes, differentiating it from earlier emm53 strains.
  • Understanding the emergence and characteristics of such clones is crucial for monitoring GAS epidemiology.

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