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Trusiano B, Todd SM, Barrett S, Ciepluch M, Fox A, McClendon D, Lahmers KK, Oakes VJ, Carvallo F, Corrigan V, LeCuyer TE. Necrotizing hepatitis caused by Clostridium novyi type B in a dog with no predisposing liver lesions: a case report. BMC Vet Res 2022; 18:366. [PMID: 36199095 PMCID: PMC9533544 DOI: 10.1186/s12917-022-03436-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 09/02/2022] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Infectious necrotic hepatitis (INH) is typically a disease of ruminants caused by Clostridium novyi type B. Growth of the causative agent is supported by development of an anaerobic environment within the liver. In dogs, C. novyi is rare and has only been previously reported as a post-mortem diagnosis. In one case, infection was secondary to metastatic pancreatic adenocarcinoma and the other was presumptively diagnosed on histopathology of a hepatic lesion in a dog initially presented for acute collapse. CASE PRESENTATION An 8-year-old spayed, female mixed breed dog was presented for acute onset of hyporexia and vomiting. Serum biochemistry revealed elevated hepatocellular injury and cholestatic liver enzymes. Ultrasound revealed peritoneal fluid accumulation and multiple hepatic masses. Cytologic examination of liver aspirates and peritoneal fluid revealed frequent 4 × 1 μm bacilli with a terminal endospore. Anaerobic bacterial growth isolated from the fluid sample could not be identified using typical laboratory identification techniques. Long-read, whole genome sequencing was performed, and the organism was identified as Clostridium novyi type B. Antimicrobial and hepatic support treatment were initiated. The patient re-presented 27 days later, and the follow up liver aspirate with cytology revealed no appreciable bacteria and anaerobic culture was negative. The patient was presented four months later and a large hepatic mass and peritoneal fluid were again identified on abdominal ultrasound. Cytologic examination of the peritoneal fluid revealed bacilli similar to those identified on initial presentation. The patient was euthanized. The most significant finding on necropsy was necrotizing hepatitis with intralesional endospore-forming bacilli compatible with recurrence of Clostridium novyi type B. There was no identifiable cause of an anaerobic insult to the liver. CONCLUSIONS This case demonstrates the diagnostic utility of using cytology as part of the initial diagnostic work up for infectious hepatitis. The cytologic findings coupled with whole genome sequencing and anaerobic culture were crucial for the identification and classification of the organism identified on fine needle aspirate. Clostridium novyi type B should be considered when bacilli organisms containing a terminal endospore are identified on liver aspirates collected from canine patients.
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Affiliation(s)
- Brie Trusiano
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, VA Tech, 205 Duck Pond Drive, Blacksburg, VA, 24061, USA.
- Virginia Tech Animal Laboratory Services, VA-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - S Michelle Todd
- Virginia Tech Animal Laboratory Services, VA-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Sarah Barrett
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, VA Tech, 205 Duck Pond Drive, Blacksburg, VA, 24061, USA
- Virginia Tech Animal Laboratory Services, VA-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
- Present Address: Zoetis, Inc., US NJ Remote, Parsippany-Troy Hills, USA
| | - Michael Ciepluch
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Alexandra Fox
- Virginia Tech Animal Laboratory Services, VA-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Diamond McClendon
- Virginia Tech Animal Laboratory Services, VA-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Kevin K Lahmers
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, VA Tech, 205 Duck Pond Drive, Blacksburg, VA, 24061, USA
- Virginia Tech Animal Laboratory Services, VA-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Vanessa J Oakes
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, VA Tech, 205 Duck Pond Drive, Blacksburg, VA, 24061, USA
- Virginia Tech Animal Laboratory Services, VA-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Francisco Carvallo
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, VA Tech, 205 Duck Pond Drive, Blacksburg, VA, 24061, USA
- Virginia Tech Animal Laboratory Services, VA-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Virginia Corrigan
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
- Present Address: Department of Rural Resilience and Innovation, Appalachian State University, Boone, NC, 28608, USA
| | - Tessa E LeCuyer
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, VA Tech, 205 Duck Pond Drive, Blacksburg, VA, 24061, USA
- Virginia Tech Animal Laboratory Services, VA-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, 24061, USA
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Abstract
Large clostridial toxins (LCTs) are a family of bacterial exotoxins that infiltrate and destroy target cells. Members of the LCT family include Clostridioides difficile toxins TcdA and TcdB, Paeniclostridium sordellii toxins TcsL and TcsH, Clostridium novyi toxin TcnA, and Clostridium perfringens toxin TpeL. Since the 19th century, LCT-secreting bacteria have been isolated from the blood, organs, and wounds of diseased individuals, and LCTs have been implicated as the primary virulence factors in a variety of infections, including C. difficile infection and some cases of wound-associated gas gangrene. Clostridia express and secrete LCTs in response to various physiological signals. LCTs invade host cells by binding specific cell surface receptors, ultimately leading to internalization into acidified vesicles. Acidic pH promotes conformational changes within LCTs, which culminates in translocation of the N-terminal glycosyltransferase and cysteine protease domain across the endosomal membrane and into the cytosol, leading first to cytopathic effects and later to cytotoxic effects. The focus of this review is on the role of LCTs in infection and disease, the mechanism of LCT intoxication, with emphasis on recent structural work and toxin subtyping analysis, and the genomic discovery and characterization of LCT homologues. We provide a comprehensive review of these topics and offer our perspective on emerging questions and future research directions for this enigmatic family of toxins.
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