Background: Clostridial bacteremia (CB) is the second most frequent anaerobic bacteremia, and CB patients show high mortality without prompt antimicrobial therapy. We retrospectively reviewed 11 years of CB cases in a tertiary care hospital to describe the clinical and microbiological characteristics of CB and to define the risk factors of fatal CB.

Methods: All patients with CB from January 2002 to December 2012 were included in the study. Age, sex, underlying diseases, antibiotic use, and clinical outcome were reviewed. Antibiotic therapy was classified as either ‘appropriate’ or ‘inappropriate’ based on the activity against Clostridium species.

Results: A total of 118 Clostridium isolates (0.79% of all blood culture isolates) were recovered from the blood cultures of 114 patients. The underlying conditions of patients with CB were neoplasm in 87 cases (76.3%), gastrointestinal symptoms in 84 cases (73.7%), diabetes in 17 cases (14.9%), and hemodialysis in six cases (5.3%). Of the 118 Clostridium isolates, C. perfringens was the most frequent species (42 isolates, 35.6%). Thirty-two patients (28.1%) showed polymicrobial bacteremia, which was most commonly combined with Escherichia coli. Two patients harbored more than two Clostridium species. ‘Appropriate’ antibiotics were given to 97 (85.1%) patients. The mortality rate of CB at days 2, 8, and 30 was 7.9% (9/114), 14.0% (16/114), and 26.3% (30/114), respectively.

Conclusion: Neoplasm, especially in the gastrointestinal tract or of hematologic origin, and hemodialysis were considered to be risk factors of blood stream clostridial infection. Early appropriate antibiotic coverage of CB was not definitely associated with lower mortality in our study. (Ann Clin Microbiol 2015;18:126-132)