Clostridium innocuum bacteremia secondary to infected hematoma with gas formation in a kidney transplant recipient

Clostridium innocuum is a relatively antimicrobial resistant, frequently misidentified anaerobe that has only rarely been associated with bacteremia. A 38-year-old female with chronic hepatitis C underwent a second kidney transplant operation. Two weeks after surgery a computed tomography scan of the abdomen showed a heterogeneous hematoma with pockets of gas adjacent to the allograft, which extended into the pelvis and left abdominal wall, associated with low-grade fever. An anaerobic blood culture grew a Clostridium initially identified as C. subterminale and later re-identified as C. innocuum. At abdominal exploration liquefied blood was evacuated, and the patient completed a course of antibiotics and recovered. C. innocuum should be considered as a cause of gas-producing anaerobic infection in transplant patients. Because C. innocuum is frequently misidentified by the use of commercial anaerobic identification kits, its true incidence in serious infections is likely underestimated.