Pyogenic study: Effect of COVID-19 pandemic on the incidence, clinical picture and outcome of Streptococcus pyogenes infection requiring intensive care admission

Background: The COVID-19 pandemic altered the incidence and transmission of multiple pathogens, including the epidemiology of infections caused by Streptococcus pyogenes . After the implementation and subsequent lifting of containment measures, several European countries reported an unexpected spike on the incidence of invasive group A Streptococcus (iGAS) infections requiring ICU admission. Methods : We conducted a multicenter retrospective study across 24 Spanish intensive care units (ICUs) including adults admitted with confirmed iGAS infection between 2018 and 2023. Epidemiological, clinical, and microbiological characteristics were compared between the prepandemic (2018–January 2020) and post-pandemic (February 2020–2023) periods. Results: A total of 195 patients were included (59% male, median age 55 years). Skin and soft tissue infections were the most common source (53%), followed by pneumonia (39%). The annual incidence of iGAS dropped markedly in 2021 and increased nearly two-fold in the postpandemic period (RR = 1.96, 95% CI 1.47–2.62). This rise was mainly driven by pneumonia, which accounted for 44.5% of post-pandemic cases compared with 28.4% pre-pandemic (p < 0.001). Post-pandemic patients showed higher rates of acute respiratory distress syndrome, prolonged mechanical ventilation, increased need for extracorporeal membrane oxygenation, and longer ICU stays, though mortality remained stable (around 20%). All S.pyogenes showed sensibility to penicillin and very low rates of resistance to clindamycin and macrolides. Conclusions : Following the COVID-19 pandemic, ICU admissions for iGAS infections increased substantially in Spain, primarily due to a surge in respiratory involvement. These findings highlight the impact of the pandemic on bacterial epidemiology and emphasize the need for continuous surveillance of post-viral shifts in pathogen dynamics.