Epidemiological trends of invasive Streptococcus pyogenes infections in Catalonia, 2022–2024: a two-year analysis

OBJECTIVES: Invasive group A streptococcal (iGAS) infections resurged across Europe in late 2022. We aimed to describe the incidence, clinical characteristics, and outcomes of iGAS in Catalonia over two epidemic seasons (2022/23 and 2023/24), and to identify risk factors associated with mortality. METHODS: A prospective study was conducted including all confirmed iGAS cases reported to the Microbiological Reporting System of Catalonia between October 2022 and October 2024. Epidemiological and clinical data were collected from medical files and incidence rates (IRs) calculated. Multivariable logistic regression was used to assess risk factors associated with mortality. RESULTS: A total of 589 laboratory-confirmed iGAS cases were included; 416 cases (70.6%) from 2022/23 season, and 173 (29.4%) from 2023/24. The overall IR decreased from 5.3 to 2.2 cases per 100,000 population (p < 0.001). In 2022/23, incidence was higher in children (0-14 years) than in adults (9.8 vs. 4.6 per 100,000; p < 0.001), whereas this pattern reversed in 2023/24 (1.7 vs. 2.3; p = 0.028). Pleural empyema predominated in children, while skin and soft tissue infections with bacteraemia in adults. Respiratory viral coinfections were more common in children than in adults (47.1% vs. 10.8%; p < 0.001). Overall, 97.3% of patients were hospitalized, and 26.9% required intensive care (33.3% in children vs. 25.2% in adults; p = 0.08). Overall mortality was 11.3% (12.9% in adults and 5.8% in children: p < 0.05). Multivariable analyses showed age, respiratory viral coinfections, chronic renal disease, and intensive care unit admission independently associated with mortality. CONCLUSIONS: The decline in iGAS incidence in 2023/24 was accompanied by a shift in age distribution and a reduction in respiratory viral coinfections, suggesting a return toward pre-pandemic epidemiological patterns. Further research is needed to clarify pathogenic mechanisms and outcome determinants.

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Journal
Infection
Published
2026-06-18
DOI
https://doi.org/10.1007/s15010-026-02835-6
Primary Topic
Streptococcal Infections and Treatments
Type
article
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article

Epidemiological trends of invasive Streptococcus pyogenes infections in Catalonia, 2022–2024: a two-year analysis

Teresa Llovet, Belén Viñado, Carme Galles, Mireia Rajadell et al.
Infection
Streptococcal Infections and Treatments
article

Epidemiological trends of invasive Streptococcus pyogenes infections in Catalonia, 2022–2024: a two-year analysis

Teresa Llovet, Belén Viñado, Carme Galles, Mireia Rajadell, Guillem Vidal, Antoni Soriano‐Arandes, Ana Siverio, Cristina Esteva, Dàmaris Berbel, Aurora Sabrià, Sílvia Capilla, Sonia Broner, C D Miralles, Victoria Rello-Saltor, Mar Olga Pérez-Moreno, Marta Martorell, I. Valle, M Dolores Quesada, Frederic Gomez-Bertomeu, Laura Solaz, Natàlia Roca, Elisabet Folch, Mariana Fernández-Pittol, Jacobo Mendioroz, F. Xavier Queralt, Pep Ballester, Pilar Ciruela, Maria Navarro, Alba Bellés, Jordi Duran, Yuliya Poliakova, M. Dolors Estivill
article en

Abstract

OBJECTIVES: Invasive group A streptococcal (iGAS) infections resurged across Europe in late 2022. We aimed to describe the incidence, clinical characteristics, and outcomes of iGAS in Catalonia over two epidemic seasons (2022/23 and 2023/24), and to identify risk factors associated with mortality. METHODS: A prospective study was conducted including all confirmed iGAS cases reported to the Microbiological Reporting System of Catalonia between October 2022 and October 2024. Epidemiological and clinical data were collected from medical files and incidence rates (IRs) calculated. Multivariable logistic regression was used to assess risk factors associated with mortality. RESULTS: A total of 589 laboratory-confirmed iGAS cases were included; 416 cases (70.6%) from 2022/23 season, and 173 (29.4%) from 2023/24. The overall IR decreased from 5.3 to 2.2 cases per 100,000 population (p < 0.001). In 2022/23, incidence was higher in children (0-14 years) than in adults (9.8 vs. 4.6 per 100,000; p < 0.001), whereas this pattern reversed in 2023/24 (1.7 vs. 2.3; p = 0.028). Pleural empyema predominated in children, while skin and soft tissue infections with bacteraemia in adults. Respiratory viral coinfections were more common in children than in adults (47.1% vs. 10.8%; p < 0.001). Overall, 97.3% of patients were hospitalized, and 26.9% required intensive care (33.3% in children vs. 25.2% in adults; p = 0.08). Overall mortality was 11.3% (12.9% in adults and 5.8% in children: p < 0.05). Multivariable analyses showed age, respiratory viral coinfections, chronic renal disease, and intensive care unit admission independently associated with mortality. CONCLUSIONS: The decline in iGAS incidence in 2023/24 was accompanied by a shift in age distribution and a reduction in respiratory viral coinfections, suggesting a return toward pre-pandemic epidemiological patterns. Further research is needed to clarify pathogenic mechanisms and outcome determinants.

Infection
Hospital Sant Joan de Déu Barcelona (ES), Generalitat de Catalunya (ES), Universitat de Girona (ES), Instituto de Salud Carlos III (ES), Hospital de Sant Pau (ES), Bellvitge University Hospital (ES), Hospital Universitari Arnau de Vilanova (ES), Althaia (ES), Clínica Girona (ES), Institut de Recerca Biomèdica Catalunya Sud (ES), Vall d'Hebron Institut de Recerca (ES), Hospital de l'Esperança (ES), Hospital Clínic de Barcelona (ES), Hospital de Sabadell (ES), Vall d'Hebron Hospital Universitari (ES), Fundació Salut i Envelliment UAB (ES), Hospital Del Mar (ES), Parc de Salut (ES), Instituto de Investigación Biomédica de Lleida (ES), Hospital de Mataró (ES), Centro Nacional de Análisis Genómico (ES), Hospital Sant Jaume de Calella (ES), Hospital Universitari de Vic (ES), Hospital Universitari Sant Joan de Reus (ES), Hospital Universitari Joan XXIII de Tarragona (ES), Ecosystem (Spain) (ES), Hospital Universitari de Tortosa Verge de la Cinta (ES), Hospital Universitari Germans Trias i Pujol (ES), Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (ES), Hospital Universitari de Girona Doctor Josep Trueta (ES), Hospital Comarcal de Inca (ES), Hospital de Palamós (ES), Fundació Salut Empordà, National Institute for Astrophysics (IT)
Good health and well-being
Openalex Percentile: Top 6%
Streptococcal Infections and Treatments
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