2 81 87 73 76 Table 1: Cases of C. septicum infection. Case Reports in Medicine Age Gender Hx of colon CA Clinical presentation Male Male Male Female None None None Resected proximal colon CA 2 days of fever Steady, mild RLQ pain for 1 week and fever for 1 day Fever for 1 day, weakness unsteady gait Fever with diﬀuse lower abdominal pain Evaluation CT: liver metastases Colonoscopy: recurrent carcinoma CT: cecal mass, liver metastases Colonoscopy: carcinoma CT: thickened ascending colon wall; periaortic gas (aortitis) Colonoscopy: carcinoma CT: cecal mass Colonoscopy: carcinoma Outcome Palliative care Palliative care In-hospital death Surgical resection Table 2: Clinical spectrum of C. septicum. Cellulitis Fasciitis Aortitis Myonecrosis (gas gangrene) Abscess (visceral or soft tissue) Aortic aneurysm (ruptured or unruptured) Septic Arthritis Septic shock Abdominal pain Fever, malaise Hemolysis to 70% [2–4]. Virulence may be related to production of multiple toxins, aggressive tissue invasion, and infection in compromised hosts [10]. C. septicum is a gram positive, anaerobic, spore-forming rod which grows normally in soil. The postulated mechanism of infection in colon cancer involves disruption of the normal mucosal barrier due to tumor-induced ulceration, followed by bloodstream invasion. Anaerobic glycolysis in the tumor may provide an acidic and hypoxic environment facilitating spore germination [2]. Cecal tumors are most common, as in all of our patients, possibly due to pH, osmotic, and elec- trolyte characteristics conducive to growth of the organism [11]. Subsequently, the organism sporulates and spreads to local intestinal mucosa. With colonic mucosal disruption, C. septicum can spread hematogenously. Mucosal disruption can be caused by tumor necrosis, bowel perforation, surgery, radiation, or a medical procedure such as colonoscopy or barium enema [1, 2, 5, 6]. Impaired host immunity from alcohol abuse, steroids, atherosclerosis, diabetes, or neutropenia is also believed to facilitate translocation. The clinical spectrum of C. septicum is diverse (Table 2), most commonly presenting as cellulitis, fasciitis, myonecro- sis, gas gangrene, or visceral or soft tissue abscess. A poten- tially catastrophic soft tissue manifestation is nontraumatic spontaneous gas gangrene. This organism, more aerotolerant than C. perfringens, is thus more likely to infect healthy tissue. Nonspeciﬁc symptoms of fever or abdominal pain are common [3]. Aortitis, a rare manifestation occurring in one of our patients, can present with nonspeciﬁc symptoms such as fever or abdominal pain. Diagnosis is most commonly made by CT scan showing a soft tissue prominence surrounding a normal aorta initially and later development of peri-aortic gas. It may also present as life-threatening aortic aneurysmal rupture. In a review of C. septicum aortitis, 21 of 23 cases were associated with colonic adenocarcinoma or polyps [11]. This infection has been proposed to result from hematoge- nous seeding of an atheromatous aorta from a distant source of bacteremia [6, 11]. A rare mechanism is direct extension of infection, such as from contiguous colonic perforation [11]. The diagnosis of C. septicum-associated large bowel malignancy may be delayed or missed. Clinical manifesta- tions are commonly nonspeciﬁc, mimicking more common disorders. At times, no clinical clue to a colon malignancy is present. Some clinicians may be unaware of the association. Bacterial sepsis may be the initial feature of previously undiagnosed and unsuspected large bowel carcinoma. In our small series, 4 of 15 cases of C. septicum sepsis had associated large bowel malignancy. All patients with blood cultures positive for this organism should undergo colonoscopy, as in our 4 patients. Unexplained fever in patients with known large bowel cancer should prompt consideration of this organism. Because malignant tumors can occur as long as several years after infection, follow-up evaluation is imperative [5]. Although commonly associated with necrotizing skin or soft tissue infections, C. septicum can present with nonspeciﬁc symptoms or a variety of other infections and should prompt consideration of malignancy. References [1] J. Dylewski and L. Luterman, “Septic arthritis and Clostridium septicum: a clue to colon cancer,” Canadian Medical Associa- tion Journal, vol. 182, no. 13, pp. 1446–1447, 2010. [2] N. N. Mirza, J. M. McCloud, and M. J. Cheetham, “Clostrid- ium septicum sepsis and colorectal cancer—a reminder,” World Journal of Surgical Oncology, vol. 7, article no. 73, 2009. [3] S. S. B. Chew and D. Z. Lubowski, “Clostridium septicum and malignancy,” ANZ Journal of Surgery, vol. 71, no. 11, pp. 647– 649, 2001. [4] A. A. Khan and K. Davenport, “A reminder of the association between Clostridium septicum and colonic adenocarcinoma,” International Seminars in Surgical Oncology, vol. 3, article no. 12, 2006. [5] G. K. Wentling, P. P. Metzger, E. J. Dozois, H. K. Chua, and M. Krishna, “Unusual bacterial infections and colorectal carcinoma—streptococcus bovis and Clostridium septicum: report of three cases,” Diseases of the Colon and Rectum, vol. 49, no. 8, pp. 1223–1227, 2006.