Clostridium tertium in neutropenic patients: case series at a cancer institute

Objective: Clostridium tertium is considered an uncommon pathogen in humans, but is a cause of bacteremia in patients with underlying hematological malignancies and neutropenia. A case series highlighting 10 years of experience with C. tertium as a cause of bacteremia in this population is presented; the cases were seen at a National Cancer Institute designated cancer center. Methods: Institutional review board approval was obtained prior to the start of the study. All cases of C. tertium bacteremia seen at H. Lee Moffitt Cancer Center and Research Institute from 2005 to 2015 were reviewed. The study population was identified by positive blood cultures obtained from the microbiology laboratory over the same time period. Results: Seven patients were found to have had C. tertium bacteremia. These patients had a temperature of >38.3 °C at the time of diagnosis and severe neutropenia. All patients had a history of hematological malignancy, five having acute myeloid leukemia and two having myelodysplastic syndrome. All of the patients’ blood cultures cleared within ≤3 days of antibiotic therapy. Conclusions: The unusual susceptibility pattern of C. tertium, with resistance to beta-lactams and clindamycin, likely explains its presence in immunosuppressed patients. Vancomycin remains the drug of choice. The pathogen continues to have a low virulence and a low mortality when treated appropriately