Manifestations and Biomarkers to Predict Mortality Risk in Adults with Invasive Streptococcus dysgalactiae

Purpose: The incidence of invasive Streptococcus dysgalactiae subsp. equisimilis (iSDSE) infections is increasing in developed countries, but studies on the risk factors for death in iSDSE infection are scant. Here, we aimed to clarify risk factors and predictors of mortality in adults with iSDSE infection. Methods: A multicentre observational study of adults with iSDSE infection (n = 588) was conducted to investigate the effects of host factors, disease severity, biomarkers, and antibiotic regimens, and bacterial factors on 28-day mortality. Results: The overall mortality rate was 10.4%, with a significant increase in those aged ≥60 years. Most of the patients (97.4%) had some underlying diseases. The mortality rate (70.4%) of patients with severe disease was significantly higher than that of patients with mild-to-moderate disease (4.3%). The risk factors for death identified using multivariate analysis were age ≥60 years (hazard ratio [HR], 3.4; 95% confidence interval [CI], 1.0–11.3, p = 0.042); severe disease (HR, 15.0; 95% CI 7.7–29.2, p < 0.001); bacteraemia without primary focus (HR, 20.5; 95% CI 2.8–152.3, p = 0.003); serum creatinine ≥2.0 mg/dL (HR, 2.2; 95% CI 1.2–4.0, p = 0.010); serum creatine kinase ≥300 IU/L (HR, 2.1; 95% CI 1.1–3.8, p = 0.019); and macrolide resistance (HR, 1.8; 95% CI 1.0–3.3, p = 0.048). Treatment regimens and emm types were not associated with poor outcomes. Conclusion: Evaluation of clinical manifestations and biomarkers on admission is important to predict invasive SDSE infection prognosis.