Positive Clostridium difficile Stool Assay in a Patient with Fatal C. sordellii Infection
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《新英格兰医药杂志》
To the Editor: A 61-year-old woman presented with nausea, vomiting, abdominal pain, and nonbloody diarrhea. A stool assay for Clostridium difficile was positive (C. difficile Tox A/B II, Tech Laboratory), and she was treated with metronidazole. However, her symptoms worsened during the subsequent week, prompting her to return to the hospital. On examination, her vital signs were normal apart from tachypnea. The abdominal examination revealed diffuse tenderness but no peritoneal signs. Laboratory evaluation revealed a hemoglobin level of 129 g per liter, a white-cell count of 75.6x109 per liter (with increased bands at 8.3x109 per liter and circulating metamyelocytes and myelocytes), and a lactate level of 4.8 mmol per liter. Computed tomography showed thickening of the cecum, ascending colon, and transverse colon and marked ascites.
Empirical intravenous vancomycin, piperacillin–tazobactam, and metronidazole were administered owing to concern about polymicrobial sepsis. Over the next hour, the patient became increasingly hypotensive. A right hemicolectomy was performed before she was transferred to the intensive care unit. Despite aggressive vasopressor support, she died hours later secondary to septic shock and cardiac tamponade. Gross pathological examination revealed a metastatic cecal adenocarcinoma; no pseudomembranous lesions were noted. Blood cultures were positive only for an anaerobic, endospore-forming, gram-positive bacillus identified as C. sordellii by biochemical tests and by sequencing of the 16S ribosomal RNA gene.
C. sordellii, an anaerobic, gut-associated bacterium producing exotoxins antigenically similar to those of C. difficile, has recently emerged as a cause of endometritis and fatal toxic shock syndrome in previously healthy young women undergoing medical abortion with mifepristone.1 Relatively similar clinical presentations have been observed post partum, intrapartum, and in nonobstetrical patients,2 although C. sordellii bacteremia, with or without toxic shock syndrome, has been reported primarily in nonobstetrical patients with underlying medical conditions, including cancer.3 Patients with C. sordellii–associated toxic shock syndrome typically present with weakness, nonspecific gastrointestinal symptoms, or both, followed by the sudden onset of hypotension refractory to vasopressors, third-space fluid accumulation, and cardiopulmonary arrest.1,2 Affected patients often present without fever and have marked hemoconcentration and neutrophilic leukocytosis.1,2
Although C. sordellii has not been associated with diarrheal disease in humans, its presence in the gut may cause false positive test results for C. difficile, owing to the high degree of antigenic homology between its exotoxins (lethal and hemorrhagic) and those of C. difficile (toxins B and A, respectively).4 This explains why, in the past, C. sordellii was suspected of being the cause of pseudomembranous colitis before the discovery of C. difficile.5 Our patient's blood-culture isolate revealed toxin production when it was tested with the use of the same C. difficile toxin assay used on the stool specimen. This case highlights the need to consider C. sordellii in the differential diagnosis of toxic shock syndrome in patients with a compatible clinical illness, regardless of the test results for C. difficile toxin.
Sameer Elsayed, M.D.
Kunyan Zhang, M.D., Ph.D.
University of Calgary
Calgary, AB T2L 2K8, Canada
sameer.elsayed@cls.ab.ca
References
Fischer M, Bhatnagar J, Guarner J, et al. Fatal toxic shock syndrome associated with Clostridium sordellii after medical abortion. N Engl J Med 2005;353:2352-2360.
Rorbye C, Petersen IS, Nilas L. Postpartum Clostridium sordellii infection associated with fatal toxic shock syndrome. Acta Obstet Gynecol Scand 2000;79:1134-1135.
Spera RV Jr, Kaplan MH, Allen SL. Clostridium sordellii bacteremia: case report and review. Clin Infect Dis 1992;15:950-954.
Martinez RD, Wilkins TD. Comparison of Clostridium sordellii toxins HT and LT with toxins A and B of C. difficile. J Med Microbiol 1992;36:30-36.
Rifkin GD, Fekety FR, Silva J Jr. Antibiotic-induced colitis implication of a toxin neutralised by Clostridium sordellii antitoxin. Lancet 1977;2:1103-1106.
Empirical intravenous vancomycin, piperacillin–tazobactam, and metronidazole were administered owing to concern about polymicrobial sepsis. Over the next hour, the patient became increasingly hypotensive. A right hemicolectomy was performed before she was transferred to the intensive care unit. Despite aggressive vasopressor support, she died hours later secondary to septic shock and cardiac tamponade. Gross pathological examination revealed a metastatic cecal adenocarcinoma; no pseudomembranous lesions were noted. Blood cultures were positive only for an anaerobic, endospore-forming, gram-positive bacillus identified as C. sordellii by biochemical tests and by sequencing of the 16S ribosomal RNA gene.
C. sordellii, an anaerobic, gut-associated bacterium producing exotoxins antigenically similar to those of C. difficile, has recently emerged as a cause of endometritis and fatal toxic shock syndrome in previously healthy young women undergoing medical abortion with mifepristone.1 Relatively similar clinical presentations have been observed post partum, intrapartum, and in nonobstetrical patients,2 although C. sordellii bacteremia, with or without toxic shock syndrome, has been reported primarily in nonobstetrical patients with underlying medical conditions, including cancer.3 Patients with C. sordellii–associated toxic shock syndrome typically present with weakness, nonspecific gastrointestinal symptoms, or both, followed by the sudden onset of hypotension refractory to vasopressors, third-space fluid accumulation, and cardiopulmonary arrest.1,2 Affected patients often present without fever and have marked hemoconcentration and neutrophilic leukocytosis.1,2
Although C. sordellii has not been associated with diarrheal disease in humans, its presence in the gut may cause false positive test results for C. difficile, owing to the high degree of antigenic homology between its exotoxins (lethal and hemorrhagic) and those of C. difficile (toxins B and A, respectively).4 This explains why, in the past, C. sordellii was suspected of being the cause of pseudomembranous colitis before the discovery of C. difficile.5 Our patient's blood-culture isolate revealed toxin production when it was tested with the use of the same C. difficile toxin assay used on the stool specimen. This case highlights the need to consider C. sordellii in the differential diagnosis of toxic shock syndrome in patients with a compatible clinical illness, regardless of the test results for C. difficile toxin.
Sameer Elsayed, M.D.
Kunyan Zhang, M.D., Ph.D.
University of Calgary
Calgary, AB T2L 2K8, Canada
sameer.elsayed@cls.ab.ca
References
Fischer M, Bhatnagar J, Guarner J, et al. Fatal toxic shock syndrome associated with Clostridium sordellii after medical abortion. N Engl J Med 2005;353:2352-2360.
Rorbye C, Petersen IS, Nilas L. Postpartum Clostridium sordellii infection associated with fatal toxic shock syndrome. Acta Obstet Gynecol Scand 2000;79:1134-1135.
Spera RV Jr, Kaplan MH, Allen SL. Clostridium sordellii bacteremia: case report and review. Clin Infect Dis 1992;15:950-954.
Martinez RD, Wilkins TD. Comparison of Clostridium sordellii toxins HT and LT with toxins A and B of C. difficile. J Med Microbiol 1992;36:30-36.
Rifkin GD, Fekety FR, Silva J Jr. Antibiotic-induced colitis implication of a toxin neutralised by Clostridium sordellii antitoxin. Lancet 1977;2:1103-1106.