9 Clostridium Septicum bacteremia in patient with colonic adenocarcinoma: a case report

Introduction The association between some bacterial infections and colorectal cancer is well documented. The best described to date is Streptococcus bovis infection. Another bacterium associated with colorectal neoplasia is Clostridium septicum. Clostridium septicum (C. septicum) is a zoonotic, anaerobic, gram-positive bacillus that is part of the human gastrointestinal flora. C. septicum bacteremia can cause various symptoms such as atraumatic myonecrosis, intestinal necrosis, brain abscess, or encephalitis. Disseminated Clostridium septicum infection is a rare complication associated with some malignancies, particularly colorectal adenocarcinoma. Colorectal cancer can cause a bacterial translocation that allows intestinal bacteria to enter the bloodstream. Infection with Clostridium septicum is usually fatal. These features, together with the lack of clinical and laboratory evidence, make diagnosis difficult. Here we present a case of C. septicum bacteremia in a patient with colon adenocarcinoma. Case Report 57-year-old male patient with a history of diabetes mellitus and dyslipidemia presented to the emergency department with abdominal pain and fever > 38°. An urgent CT scan revealed a cecal mass with no signs of complication. The patient was admitted for full workup and clinical observation. Blood cultures were negative at that time. During hospitalization, the diagnosis of cecal adenocarcinoma without distant involvement was confirmed. The patient was discharged after a satisfactory clinical course. After presenting the case to the tumor committee, the patient was placed on the surgical waiting list for laparoscopic right hemicolectomy. Twenty days after discharge, the patient returned to the emergency department with fever and severe right iliac fossa pain. Blood cultures were obtained and an urgent CT scan showed the cecal neoplasm with signs of infection and possible fistulization to the abdominal wall. An emergent open right hemicolectomy was performed. Blood cultures revealed the presence of Clostridium septicum. Broad-spectrum intravenous antibiotic therapy was initially initiated with meropenem, followed by adjustment to amoxicillin-clavulanate based on susceptibility testing. There were no postoperative complications and the patient was discharged on postoperative day 6 with oral antibiotic therapy (amoxicillin-clavulanate) for 14 days. Pathology results confirmed cecal adenocarcinoma classified as pT4aN0. The patient is currently doing well, without any infectious complications, and is undergoing adjuvant chemotherapy. Discussion Clostridium septicum is found in the gastrointestinal tract of approximately 2% of healthy individuals and is distributed in the ileum and cecum1. C. septicum has been shown to be closely associated with complicated infections in patients with predominantly ascending colon neoplasms. The disruption of intestinal barriers due to tumor perforation allows hematogenous spread. In septic patients with colorectal cancer, the etiologic suspicion of C. septicum bacteremia should remain high2. Physicians must be aware that the detection of specific anaerobic bacteria in the blood, which are almost exclusively found in the colon, is associated with a risk of colorectal pathology, including colorectal cancer1. Antibiotic therapy remains the mainstay of treatment for C. septicum infection, with high-dose penicillin G being the first choice. Metronidazole, clindamycin, cefotixine, tetracycline or imipenem should be considered if the patient has a penicillin allergy. If sepsis is present, treatment should not be delayed given the mortality associated with this condition3. Although C. septicum infection is rare, early suspicion may improve prognosis in a condition with a high mortality rate4.