College of Medical, Veterinary and Life Sciences, Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Urquhart Building, 464 Bearsden Road, Glasgow, G61 1QH, UK.
BMC Vet Res. 2020 May 24;16(1):152. doi: 10.1186/s12917-020-02362-y.
Canine hemorrhagic gastroenteritis (also canine gastrointestinal hemorrhagic syndrome) is commonly associated with Clostridium perfringens, although in some cases the etiology remains unclear. This report describes a fatal acute hemorrhagic and necrotizing gastroenteropathy in a dog associated with Clostridium sordellii, a bacterial species never before identified as the etiological agent of hemorrhagic and necrotizing gastroenteropathy in dogs.
A fully vaccinated, eight-year-old, female neutered Labrador presented with a history of vomiting without diarrhea. Clinical examination revealed pink mucous membranes, adequate hydration, normothermia, and normocardia. The dog was discovered deceased the following day. Post-mortem examination showed moderate amounts of dark red, non-clotted fluid within the stomach that extended into the jejunum. Discoloration was noted in the gastric mucosa, liver, lungs, and kidneys, with small petechial hemorrhages present in the endocardium over the right heart base and thymic remnants. Histological analysis demonstrated that the gastric fundic mucosa, the pyloric region, small intestine, and large intestine exhibited superficial coagulative necrosis and were lined with a layer of short Gram-positive rods. Anaerobic culture of the gastric content revealed C. sordellii as the dominant bacterial species and neither Salmonella spp., Campylobacter spp., C. perfringens, nor C. difficile were isolated. Unexpectedly, whole genome sequencing of the C. sordellii isolate showed that it lacked the main plasmid-encoded virulence factors typical of the species, indicating that the genetic determinants of pathogenicity of this strain must be chromosomally encoded. Further phylogenetic analysis revealed it to be genetically similar to C. sordellii isolates associated with gastroenteric disease in livestock, indicating that the infection may have been acquired from the environment.
This case demonstrates that C. sordellii can associate with a canine hemorrhagic and necrotizing gastroenteropathy in the absence of C. perfringens and illustrates the benefits of using bacterial whole genome sequencing to support pathological investigations in veterinary diagnostics. These data also update the molecular phylogeny of C. sordellii, indicating a possible pathogenic clade in the environment that is distinct from currently identified clades.
犬出血性胃肠炎（也称为犬胃肠道出血综合征）通常与梭状芽孢杆菌属的产气荚膜梭菌相关，尽管在某些情况下病因仍不清楚。本报告描述了一例与梭状芽孢杆菌属的索氏梭菌相关的致命性急性出血性和坏死性胃肠炎，该细菌种从未被确定为犬出血性和坏死性胃肠炎的病因。
一只完全接种疫苗、8 岁、雌性去势的拉布拉多犬出现呕吐但无腹泻病史。临床检查显示黏膜呈粉红色，水合状态充足，体温正常，心率正常。第二天发现该犬死亡。尸检显示胃中有中等量暗红色、未凝固的液体，延伸至空肠。胃黏膜、肝脏、肺脏和肾脏有变色，右心基部的心内膜和胸腺残部有小瘀点出血。组织学分析显示胃底黏膜、幽门区、小肠和大肠呈现浅层凝固性坏死，并覆盖有一层短的革兰阳性杆菌。胃内容物的厌氧培养显示索氏梭菌是优势细菌，未分离到沙门氏菌属、弯曲菌属、产气荚膜梭菌或艰难梭菌。令人意外的是，索氏梭菌分离株的全基因组测序显示其缺乏该物种主要质粒编码的毒力因子，表明该菌株的致病性遗传决定因素必须是染色体编码的。进一步的系统发育分析表明，它与与家畜胃肠道疾病相关的索氏梭菌分离株在遗传上相似，表明感染可能是从环境中获得的。
本病例表明，在没有产气荚膜梭菌的情况下，索氏梭菌可与犬出血性和坏死性胃肠炎相关，并说明了在兽医诊断中使用细菌全基因组测序来支持病理研究的益处。这些数据还更新了索氏梭菌的分子系统发育，表明环境中存在一个可能的致病分支，与目前确定的分支不同。
