Characteristics of Streptococcus pyogenes causing invasive infections among adults in Portugal, 2016–2019: Pre-COVID-19 expansion of the M1UK sublineage

• Published in: Journal of Microbiology, Immunology and Infection
• Main Authors: Ana Friães, Rafael Mamede, Beatriz Santos, José Melo-Cristino, Mario Ramirez, Margarida Pinto, Miguel Seruca, João Marques, Isabel Peres, Teresa Pina, Isabel Lourenço, Cristina Marcelo, Isabel Daniel, Odete Chantre, Vasco Mendes, Marília Gião, Rui Ferreira, Rui Tomé Ribeiro, Celeste Pontes, Luísa Boaventura, Teresa Reis, Henrique Oliveira, Catarina Chaves, Mariana Silva, Ana Aguiar, Hugo Loureiro, Adriana Pedrosa, Hermínia Costa, Maria Fátima Silva, Maria Amélia Afonso, Mariana Fardilha, Natália Novais, Isabel Brito, Luís Marques Lito, Ana Bruschy Fonseca, Maria Ana Pessanha, Elsa Gonçalves, Teresa Morais, Cristina Toscano, Elisabete Cristovam, Paulo Lopes, Angelina Lameirão, Gabriela Abreu, Aurélia Selaru, Ana Paula Mota Vieira, Margarida Tomaz, Cláudia Ferreira, Marta Nicolau, Ana Paula Castro, Virgínia Lopes, Hugo Cruz, Fernando Fonseca, Nádia Martins, Carla Leite, Filipa Vicente, Margarida Pereira, Ilse Fontes, Maria Paula Falcão, Rui Semedo, Gina Marrão, Filipa Silva, Manuela Ribeiro, Helena Gonçalves, Alberta Faustino, Maria Cármen Iglesias, Adriana Coutinho, Ana Bela Correia, Luísa Gonçalves, Elzara Aliyeva, Sandra Schäfer, Clara Portugal, Isabel Monge, José Diogo, Filipa Fortunato, Leonardo Carneiro, José Marta, Nadiya Kruptsala, Cláudia Fidalgo, Raquel Diaz, Sónia Ferreira, Inês Cravo Roxo, Isabel Vale, Maria João Tomás, Maria Antónia Read, Valquíria Alves, Margarida Monteiro, João Faria, José Mota Freitas, Sandra Vieira, Elsa Calado, Bruno Miguel, L. Nogueira Martins, Maria Favila Menezes, Maria José Rego de Sousa, Maria Calle, Mariana Bettencourt Viana, Marvin Oliveira, Hugo Macedo, Vitória Rodrigues, Sofia Marques, Joana Selada, Patrícia Pereira, Manuela Azevedo, Jesuína Duarte, Joana Bernardo, Inês Tapadinhas, Ana Filipa Resende, Andreia Bernardo, Luísa Oliveira, Susana Banza, Ezequiel Moreira, Carla Ferreira, Adília Vicente, Cristina Bragança, Maria Lucas, Paula Gouveia Pestana, Patrícia Amantegui, Cristina Mota Preto, Sara F. Sampaio, Fátima Vale, Joana Ramos, Rita Gralha
• Format: Article
• Language: English
• Published: Elsevier 2025-06-01
• Online Access: http://www.sciencedirect.com/science/article/pii/S1684118225000337

Background: Genome-based epidemiological surveillance of Streptococcus pyogenes (Lancefield Group A Streptococcus, GAS) infections facilitated the detection of emergent successful lineages, such as the M1UK sublineage. This sublineage dominated the post-COVID-19 upsurge of invasive GAS infections (iGAS) in multiple countries, including Portugal. Here, we characterized the genetic lineages causing iGAS in Portugal during 2016–2019 to evaluate possible temporal trends and compare them with internationally circulating lineages. Methods: Whole-genome sequencing and antimicrobial susceptibility testing were performed for 273 iGAS isolates. Results: The dominant emm types were emm1 (n = 87), emm3 (n = 37), and emm89 (n = 26), collectively comprising 55 % of all isolates (n = 273). Throughout the study, the M1UK sublineage increased in prevalence, accounting for 48 % of all emm1 isolates. Core-genome multilocus sequence typing supports multiple introductions of M1UK in Portugal pre-COVID-19, and a limited relatedness to the M1UK isolates recovered during the post-COVID-19 surge in pediatric iGAS. Several internationally disseminated lineages expressing various emm types were identified. Mutations inactivating key regulators of virulence (CovRS and RopB) and in the capsule locus were found in a significant fraction of isolates. Macrolide resistance was primarily associated with the erm(A) and erm(B) genes and remained low (4 %), highlighting differences between Europe and North America. Conclusions: Despite adult iGAS in Portugal being caused by geographically widespread, successful GAS lineages that may be repeatedly introduced in the country, including M1UK, there was no apparent increase in disease. This is consistent with upsurges of iGAS post-COVID-19 not being driven primarily by the emergence or introduction of novel GAS clones.