Epidemiology, aetiology and clinical characteristics of clostridial bacteraemia: a 6-year population-based observational study of 386 patients.

The objective of this study is to provide a population-based clinical, epidemiological and microbiological overview of clostridial bacteraemia. All cases of bacteraemia in the Skåne Region between 2014 and 2019 with a species currently belonging to the Clostridium genus were identified in the regional clinical microbiology database. Clinical data were retrieved by medical chart-review. A total of 386 unique episodes of clostridial bacteraemia were found resulting in an incidence rate of 4.9/100.000 person-years. The median age was 76 with 56% males. The incidence rate ratio was 34.3 for those aged 80 + vs 0-59. The minimum inhibitory concentrations varied between species but were universally low for metronidazole and carbapenems. Malignancy was the most common co-morbidity, in 47% of patients and most pronounced for C. septicum. Criteria for sepsis and septic shock were met in 69% and 17%, respectively. The 28-day mortality was 26%. High age, absence of fever, high C-reactive protein and high SOFA-score were all significantly associated with mortality. We present the highest incidence rate of clostridial bacteraemia to date. Clostridial bacteraemia is a severe condition with acute onset, affecting elderly with co-morbidities, most pronounced malignancies. Mortality is related to acute manifestations rather than to background factors.