Human Clostridium chauvoei necrotising enterocolitis

Clinical record

A 48‐year‐old woman presented with three days of nausea and vomiting and two days of worsening right‐sided lower abdominal pain. Diarrhoea developed soon after presentation. She denied sick contacts and recent overseas travels but recalled a prolonged handling of gardening soil with bare hands while having multiple superficial skin lacerations acquired from a domestic cat.

Vital signs were normal, abdomen was soft without peritonism, but extremely tender on palpation in the right iliac fossa. Initial blood tests revealed profound hepatic and renal failure with lactic acidosis. Computed tomography (CT) scan of the abdomen without contrast showed normal bowel and trace free fluid in the pelvis without signs of intraperitoneal fat stranding or pneumoperitoneum. She was commenced on intravenous piperacillin–tazobactam for presumed infective enterocolitis. Due to the severity of the abdominal pain, a repeat CT scan of the abdomen was performed five hours later, demonstrating new mild fat stranding around the ascending colon and caecum.

She was admitted to the intensive care unit for close monitoring and supportive therapy. On day 2 of admission, her blood cultures returned positive for gram‐positive bacilli (Box, A), which was identified on Matrix‐assisted laser desorption ionisation–time of flight (MALDI‐TOF) mass spectrometry as Clostridium chauvoei (MALDI Biotyper, Bruker; score>2.0 [scores ≥2.0 were accepted for species assignment and scores ≥1.7 but <2.0 for identification to the genus level; scores below 1.7 were considered unreliable]).1 The organism failed to grow on agar plates for sensitivity testing. Intravenous clindamycin was added for Clostridial toxin inhibition. For treatment of a possible Clostridial necrotising enterocolitis, she was referred for locally available hyperbaric oxygen therapy (HBOT). An exploratory laparotomy was considered but not performed without evidence for bowel perforation on CT scan. She received two sessions of HBOT on days 2 and 3. Hepatic and renal function improved, and the lactic acidosis resolved before she was discharged to the general ward on day 4. On day 5, she developed functional ileus, which was conservatively managed. Total parenteral nutrition was commenced on day 6. For the subsequent three days, her abdominal pain improved but diarrhoea recommenced.

She developed an acute, severe lower abdominal pain on day 9. CT scan of the abdomen demonstrated extensive pneumoperitoneum with free intra‐abdominal fluid, consistent with bowel perforation (Box, B), and an urgent laparotomy was performed. Intra‐operative findings included perforation of the anterior caecal wall with extensive, transmural necrosis of the anterior colonic wall extending from the caecum to the distal ascending colon (Box, C and D). Right hemicolectomy and end ileostomy formation were performed. She continued to improve clinically after the operation. Paeniclostridium sordellii bacteraemia was detected on day 11, likely as a result of intra‐operative translocation. She was discharged from the hospital 2.5 weeks after the surgery and an elective reversal of end‐ileostomy was performed successfully three months after discharge.

Discussion

Clostridium chauvoei is a gram‐positive bacillus that is well described in the veterinary literature as a leading cause of fatal myonecrosis in cattle and sheep, commonly known as “blackleg”.2 The organism produces a rapid and aggressive infection in the host, and death is described as the commonest presenting symptom. The main reservoir of the organism is in the soil, where it may persist in the form of spores. Once ingested or inhaled, the spores enter the bloodstream and migrate to muscle tissues, where they remain dormant until the anaerobic trigger for germination occurs. Germination of the spores then leads to the production of virulence factors — C. chauvoei toxin A, which causes strong haemolysis, and mycolytic enzymes, such as deoxyribonuclease (DNAse) and hyaluronidase.3,4 Culturing this organism for sensitivity testing can often be challenging, as it does not survive well in the atmosphere. It is usually susceptible to penicillins and metronidazole.2,3 In our patient, we used piperacillin–tazobactam to cover for other gastrointestinal pathogens in the context of suspected enterocolitis.

We could identify only two human cases of C. chauvoei infection reported in the literature: a case of necrotising enterocolitis in an immunocompromised host and a case of gas gangrene in a trauma patient. Both cases resulted in fatality during the index admission.5,6 We suspect that, in our patient, the spores of C. chauvoei in the garden soil entered the bloodstream through the lacerations on her hands. Compared with the two reported fatal human cases, our patient did not have any significant comorbid conditions and received early antibiotic therapy, haemodynamic resuscitation, and HBOT. We advocated for a trial of HBOT based on evidence describing its efficacy in the early stages of Clostridial myonecrosis. The high concentration of oxygen inhibits bacterial growth as well as C. chauvoei toxin A production, slowing down the progression of necrosis.7 The scientific evidence specific to HBOT efficacy in C. chauvoei necrotising colitis is lacking, as is certainty regarding its contribution to the successful outcome of our patient.

The lessons from our case are centred around early diagnosis and a prompt multidisciplinary approach to the treatment. The lack of clear radiological evidence of bowel wall necrosis and perforation delayed surgical intervention in our patient. Presumably, early CT scan was unable to demonstrate mucosal bowel damage until the onset of transmural necrosis.

In conclusion, C. chauvoei is an aggressive pathogen that had been considered lethal until now. However, successful treatment is possible through a combination of appropriate surgical, resuscitative and antibiotic treatment with possible contribution from HBOT.

Box – Clostridium chauvoei bacteraemia and necrotising colitis: (A) Gram stain of blood culture showing gram‐positive bacilli (× 100); (B) computed tomography scan of the abdomen demonstrating caecal perforation; (C) macroscopic appearance of necrotising colitis;* (D) microscopic appearance of necrotising colitis^†

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* White arrowhead = normal mucosa; red arrowhead = haemorrhagic mucosa; black arrowhead = necrotic mucosa. † × 40 section of the ascending colon demonstrating transmural ulceration.