biostudies-literatureUnknown20(8)Yoon CSBacterial co-infection has been associated with adverse outcomes in patients with COVID-19. Streptococcus pneumoniae is a common cause of community-acquired pneumonia and may contribute to poor clinical outcomes when co-detected in COVID-19 patients. This study aimed to investigate the clinical significance of pneumococcal positivity in hospitalized patients with COVID-19. We conducted a retrospective analysis of adult patients hospitalized with COVID-19 at two tertiary care centers. Pneumococcal positivity was defined by either a positive urinary antigen test or multiplex real-time polymerase chain reaction. Disease severity of COVID-19 pneumonia was assessed using the pneumonia severity index and CURB-65 scoring systems. Propensity score matching and multivariable logistic regression were used to adjust for confounders and identify independent risk factors for mortality. Among 280 patients, 65 pneumococcus-positive patients were matched with 65 pneumococcus-negative patients after propensity score matching. In the overall matched cohort, pneumococcal positivity was not significantly associated with in-hospital mortality. However, in patients with severe disease (n = 156), defined as pneumonia severity index >130 or CURB-65 ≥ 3, mortality was significantly higher in pneumococcus-positive patients (n = 39) than in pneumococcus-negative patients (53.8% vs. 29.1%, p = 0.009). In the multivariable analysis of this subgroup, pneumococcal positivity (odds ratio, 4.050; 95% confidence interval, 1.285-12.765; p = 0.017) and high-flow oxygen therapy (odds ratio, 6.510; 95% confidence interval, 1.847-22.944; p = 0.004) were independently associated with mortality. Detection of S. pneumoniae by urinary antigen test or multiplex polymerase chain reaction was associated with increased mortality in patients hospitalized with severe COVID-19.PloS onee0329474https://www.ebi.ac.uk/biostudies/studies/S-EPMC12370052biostudies-literatureThe influence of pneumococcal positivity on clinical outcomes among patients hospitalized with COVID-19: A retrospective cohort study.PMC12370052Kho BGKim YIPark HYYoon CSLee JKPark HKKim TOLim SCKwon YSShin HJfalseThe influence of pneumococcal positivity on clinical outcomes among patients hospitalized with COVID-19: A retrospective cohort study.Bacterial co-infection has been associated with adverse outcomes in patients with COVID-19. Streptococcus pneumoniae is a common cause of community-acquired pneumonia and may contribute to poor clinical outcomes when co-detected in COVID-19 patients. This study aimed to investigate the clinical significance of pneumococcal positivity in hospitalized patients with COVID-19. We conducted a retrospective analysis of adult patients hospitalized with COVID-19 at two tertiary care centers. Pneumococcal positivity was defined by either a positive urinary antigen test or multiplex real-time polymerase chain reaction. Disease severity of COVID-19 pneumonia was assessed using the pneumonia severity index and CURB-65 scoring systems. Propensity score matching and multivariable logistic regression were used to adjust for confounders and identify independent risk factors for mortality. Among 280 patients, 65 pneumococcus-positive patients were matched with 65 pneumococcus-negative patients after propensity score matching. In the overall matched cohort, pneumococcal positivity was not significantly associated with in-hospital mortality. However, in patients with severe disease (n = 156), defined as pneumonia severity index >130 or CURB-65 ≥ 3, mortality was significantly higher in pneumococcus-positive patients (n = 39) than in pneumococcus-negative patients (53.8% vs. 29.1%, p = 0.009). In the multivariable analysis of this subgroup, pneumococcal positivity (odds ratio, 4.050; 95% confidence interval, 1.285-12.765; p = 0.017) and high-flow oxygen therapy (odds ratio, 6.510; 95% confidence interval, 1.847-22.944; p = 0.004) were independently associated with mortality. Detection of S. pneumoniae by urinary antigen test or multiplex polymerase chain reaction was associated with increased mortality in patients hospitalized with severe COVID-19.2025-01-01T00:00:00Z20252026-05-07T05:00:58.252Z2026-04-07T22:33:05.398ZS-EPMC123700524083969410.1371/journal.pone.0329474