Epidemiology and predictors of 30-day mortality in clinically significant Clostridium species infections

Purpose Clostridium species are an under-recognized cause of severe infections with substantial mortality, yet national data remain limited. This study aimed to characterize the epidemiological, microbiological, clinical, and therapeutic features of clinically significant Clostridium spp. infections and to identify factors associated with 30-day mortality. Methods We conducted a retrospective, single-centre cohort study at Unidade Local de Saúde de Gaia-Espinho (Portugal), including all patients with clinically significant Clostridium spp. isolates between 1 January 2020 and 30 March 2025. Demographic, clinical, microbiological, and therapeutic data were obtained from electronic medical and laboratory records. The primary outcome was 30-day all-cause mortality. Survivors and non-survivors were compared using univariate and multivariable logistic regression analyses. Results A total of 119 patients were included (median age 68.9 years). Most infections were community-acquired (73.1%), and C. perfringens was the most frequently identified species (58.8%). Thirty-day mortality was 22.7%. In univariate analysis, mortality was associated with older age, thrombocytopenia, hepatic and renal dysfunction, bacteremia, sepsis or septic shock, inadequate antimicrobial therapy, and lack of source control. In Firth penalised logistic regression, age (OR 1.09/year, 95% CI 1.04–1.16), hepatic dysfunction (OR 6.74, 95% CI 2.05–25.87), and septic shock (OR 56.41, 95% CI 11.11–458.37) were associated with mortality; adequate antimicrobial therapy was protective (OR 0.09, 95% CI 0.02–0.37). Conclusion Clostridium spp. infections were associated with high mortality. Age and organ dysfunction were key risk factors, whereas early appropriate antimicrobial therapy was the main modifiable protective factor. Prompt recognition, timely antibiotics, and adequate source control are essential.