Changes in emm types and superantigen gene content of Streptococcus pyogenes causing invasive infections in Portugal

Sci Rep. 2019 Dec 2;9(1):18051. doi: 10.1038/s41598-019-54409-2.

Abstract

Fluctuations in the clonal composition of Group A Streptococcus (GAS) have been associated with the emergence of successful lineages and with upsurges of invasive infections (iGAS). This study aimed at identifying changes in the clones causing iGAS in Portugal. Antimicrobial susceptibility testing, emm typing and superantigen (SAg) gene profiling were performed for 381 iGAS isolates from 2010-2015. Macrolide resistance decreased to 4%, accompanied by the disappearance of the M phenotype and an increase of the iMLSB phenotype. The dominant emm types were: emm1 (28%), emm89 (11%), emm3 (9%), emm12 (8%), and emm6 (7%). There were no significant changes in the prevalence of individual emm types, emm clusters, or SAg profiles when comparing to 2006-2009, although an overall increasing trend was recorded during 2000-2015 for emm1, emm75, and emm87. Short-term increases in the prevalence of emm3, emm6, and emm75 may have been driven by concomitant SAg profile changes observed within these emm types, or reflect the emergence of novel genomic variants of the same emm types carrying different SAgs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Anti-Bacterial Agents / pharmacology*
  • Anti-Bacterial Agents / therapeutic use
  • Antigens, Bacterial / genetics*
  • Antigens, Bacterial / isolation & purification
  • Bacterial Outer Membrane Proteins / genetics*
  • Bacterial Outer Membrane Proteins / isolation & purification
  • Carrier Proteins / genetics*
  • Carrier Proteins / isolation & purification
  • Child
  • Child, Preschool
  • DNA, Bacterial / genetics
  • DNA, Bacterial / isolation & purification
  • Drug Resistance, Bacterial / genetics
  • Female
  • Humans
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Molecular Epidemiology
  • Molecular Typing
  • Portugal / epidemiology
  • Streptococcal Infections / drug therapy*
  • Streptococcal Infections / epidemiology
  • Streptococcal Infections / immunology
  • Streptococcal Infections / microbiology
  • Streptococcus pyogenes / classification*
  • Streptococcus pyogenes / drug effects
  • Streptococcus pyogenes / isolation & purification
  • Streptococcus pyogenes / physiology
  • Superantigens / genetics*
  • Superantigens / immunology
  • Superantigens / isolation & purification
  • Young Adult

Substances

  • Anti-Bacterial Agents
  • Antigens, Bacterial
  • Bacterial Outer Membrane Proteins
  • Carrier Proteins
  • DNA, Bacterial
  • Superantigens
  • streptococcal M protein