Journal Article

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

Melo-Cristino, J., Ramirez, M., Friães, A.

2019

Overview

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 iMLS B phenotype. The dominant emm types were: emm 1 (28%), emm 89 (11%), emm 3 (9%), emm 12 (8%), and emm 6 (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 emm 1, emm 75, and emm 87. Short-term increases in the prevalence of emm 3, emm 6, and emm 75 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.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 45 / 45/22 / 45/23 / 45/77 / 631/326/107 / 631/326/22/1434 / 631/326/41/1470 / Adolescent / Adult / Aged / Anti-Bacterial Agents - pharmacology / Anti-Bacterial Agents - therapeutic use / Antigens, Bacterial - genetics / Antigens, Bacterial - isolation & purification / Antimicrobial agents / Bacterial Outer Membrane Proteins - genetics / Bacterial Outer Membrane Proteins - isolation & purification / Carrier Proteins - genetics / Carrier Proteins - isolation & purification / Child / Child, Preschool / Cloning / DNA, Bacterial - genetics / DNA, Bacterial - isolation & purification / Drug resistance / Drug Resistance, Bacterial - genetics / Female / Genes / Genetic diversity / Genotype & phenotype / Humanities and Social Sciences / Humans / Infections / Male / Microbial Sensitivity Tests / Middle Aged / Molecular Epidemiology / Molecular Typing / multidisciplinary / Phenotypes / Portugal - epidemiology / Science / Science (multidisciplinary) / Streptococcal Infections - drug therapy / Streptococcal Infections - epidemiology / Streptococcal Infections - immunology / Streptococcal Infections - microbiology / Streptococcus / Streptococcus infections / Streptococcus pyogenes - classification / Streptococcus pyogenes - drug effects / Streptococcus pyogenes - isolation & purification / Streptococcus pyogenes - physiology / Superantigens - genetics / Superantigens - immunology / Superantigens - isolation & purification / Vaccines / Virulence / Young Adult