Chronic enteropathy (CE) or chronic inflammatory enteropathy is a group of diseases with multiple and different etiologies characterized by chronic gastrointestinal signs such as vomiting, diarrhea, anorexia, weight loss for more than 3 weeks, and inflammatory cell infiltration, such as lymphoplasmacytic cells in the intestinal mucosal lamina propria. The diagnosis was histologically confirmed after excluding other diseases such as parasitic infections, tumors, pancreatitis, exocrine pancreatic insufficiency, metabolic diseases, and endocrine diseases, such as hypoadrenocorticism. Nutritional management depends on several important functions, such as digestion and absorption processes, digestive enzymes and nutritional transporters, and barrier functions. Intestinal dysbiosis may have been found to be involved in various functions. Recently, cobalamin (vitamin B12) and vitamin D have been considered negative prognostic factors in dogs with CE. Cobalamin supplementation ameliorates clinical disease severity in dogs with CE, and vitamin D supplementation ameliorates hypocalcemia in dogs with CE and hypoalbuminemia. Therefore, the aim of this review is to provide an overview of CE and present treatment and nutritional management strategies for CE and prognostic vitamins.

Granulomatous colitis, or ulcerative colitis, is an infectious and inflammatory disease that primarily affects the colon and occasionally extends to the ileum, particularly in young Boxer and French Bulldogs. Unlike typical chronic colitis in small animals, the early onset of the disease suggests a genetic predisposition. The condition is characterized by the overgrowth of Escherichia coli, specifically the enteroinvasive variant, which displaces beneficial gut bacteria, contributing to its infectious nature. Secondary dysbiosis and chronic-active inflammation involving histiocytes and other leukocytic infiltrates are prominent features. Clinical manifestations include chronic diarrhea with blood and mucus, frequent tenesmus, and pain, with variable degrees of weight loss depending on disease severity. The final diagnosis is based on clinical history (chronic diarrhea with hematochezia), macroscopic findings from colonoscopy (edema, ulcers, and wall hyperplasia), histopathology (presence of histiocytes), and Escherichia coli growth in culture from a colon fragment. Treatment is guided by colon antibiograms, which often require prolonged antibiotic therapy. Fecal microbiota transplantation (FMT) has emerged as a potential treatment, either as a primary intervention or adjunctive therapy, for conditions such as acute enteritis (e.g., canine parvovirus), dysbiosis, and chronic enteropathies. However, its application to modulate the microbiota and reduce inflammation in granulomatous colitis, potentially leading to longer intervals between relapses, remains an area of ongoing investigation. This is a case report of a French Bulldog diagnosed with ulcerative colitis accompanied by dysbiosis and refractory to standard treatments but sensitive and partially responsive to amikacin. The patient achieved control and sustained improvement in fecal scoring following fecal transplantation. This approach prevented the need for additional antibiotic therapy, ensuring clinical amelioration alongside microbiome restoration.

Granulomatous diseases associated with Escherichia coli infection are uncommon in domestic animals. In cats, malakoplakia and granulomatous ulcerative colitis are the only described forms. We investigated the clinical and pathological findings of E. coli-associated granulomatous diseases in three cats. In all cases the affected organs were infiltrated by many macrophages containing periodic acid-Schiff-positive intracytoplasmic granules. The macrophages immunolabelled for ionized calcium-binding adapter molecule 1 and E. coli. The first case involved the urinary bladder and was diagnosed as malakoplakia. The second case had small intestinal granulomatous enteritis and lymphadenitis of the mesenteric, celiac, colonic, mandibular and mediastinal lymph nodes. The third case had granulomatous enteritis, splenitis and lymphadenitis of the mesenteric, iliac, aortic, renal, hypogastric and sacral lymph nodes. Peyer's patches were predominantly affected in the small intestines of both the second and third cases. Although malakoplakia has been documented previously, the findings in the second and third cases suggest novel forms of granulomatous disease associated with E. coli in cats, with notable primary involvement of lymphoid tissue.

FISH techniques have been applied for the visualization and identification of intracellular bacteria in companion animal species. Most frequently, these techniques have focused on the identification of adhesive-invasive Escherichia coli in gastrointestinal disease, although various other organisms have been identified in inflammatory or neoplastic gastrointestinal disease. Previous studies have investigated a potential role of Helicobacter spp. in inflammatory gastrointestinal and hepatic conditions. Other studies evaluating the role of infectious organisms in hepatopathies have received some attention with mixed results. FISH techniques using both eubacterial and species-specific probes have been applied in inflammatory cardiovascular, urinary, and cutaneous diseases to screen for intracellular bacteria. This review summarizes the results of these studies.

A 7.5-year-old neutered male Oriental Shorthair cat presented with an 8-month history of haematochezia, mucoid diarrhoea, tenesmus and vocalisation after a 4-year history of small bowel diarrhoea. Transabdominal ultrasonography confirmed diffuse colonic wall thickening and extensive ulceration and erythema after colonoscopy. Colonic histopathology confirmed periodic acid-Schiff positive macrophages, consistent with granulomatous colitis; Escherichia coli was cultured from colonic biopsy specimens. Fluorescent in situ hybridisation (FISH) identified intracellular E coli, and an 8-week oral course of marbofloxacin, a hydrolysed protein diet and a 5-day course of fenbendazole yielded a transient partial clinical remission of the colitis signs. A reported resolution in the small bowel signs was also reported. Colonoscopy was repeated 5 months later due to the recurrence of colitis signs. Histopathology was not consistent with granulomatous colitis supporting a complete remission; however, a chronic inflammatory enteropathy was confirmed with moderate lymphoplasmacytic, neutrophilic and eosinophilic colitis without a histiocytic component. E coli was again cultured from colonic biopsies with sensitivity to fluoroquinolones; FISH was positive for intracellular E coli. Clinical signs persisted despite a 2-week course of oral marbofloxacin.

E coli-associated granulomatous colitis is rare in cats. Colonic biopsy specimen culture is important to guide appropriate antibiotic therapy. Repeat histopathology, culture and FISH have not been previously reported after treatment of a cat with E coli-associated granulomatous colitis. Persistent clinical signs after treatment with oral marbofloxacin alongside a confirmed complete histologic remission support the presence of a concurrent chronic inflammatory enteropathy and pathology for the cat's ongoing colitis.

Gut microbiota imbalances play an important role in inflammatory bowel disease (IBD), but no single pathogenic microorganism critical to IBD that is specific to the IBD terminal ileum mucosa or can invade intestinal epithelial cells has been found. Invasive Escherichia coli (E. coli) adhesion to macrophages is considered to be closely related to the pathogenesis of inflammatory bowel disease. Further study of the specific biological characteristics of adherent invasive E. coli (AIEC) may contribute to a further understanding of IBD pathogenesis. This review explores the relationship between AIEC and the intestinal immune system, discusses the prevalence and relevance of AIEC in Crohn's disease and ulcerative colitis patients, and describes the relationship between AIEC and the disease site, activity, and postoperative recurrence. Finally, we highlight potential therapeutic strategies to attenuate AIEC colonization in the intestinal mucosa, including the use of phage therapy, antibiotics, and anti-adhesion molecules. These strategies may open up new avenues for the prevention and treatment of IBD in the future.

Granulomatous colitis in dogs can be associated with infection of the colonic mucosa by invasive strains of Escherichia coli. To date, fluorescence in situ hybridization (FISH) is the gold-standard method to assess intramucosal and intracellular bacterial invasion. However, FISH requires expensive fluorescence microscopy equipment and is therefore not widely available. We investigated the use of immunohistochemistry (IHC) as an alternative method to detect invasive E. coli in dogs with granulomatous colitis. Archived paraffin-embedded blocks were selected from 26 dogs with colitis, in which FISH had been performed by an outside laboratory. Using a polyclonal antibody, IHC for E. coli was performed on sections cut from the same blocks, and the presence of invasive E. coli was recorded. All 11 specimens in which FISH had detected E. coli were also positive on IHC, with strong immunolabeling in the cytoplasm of macrophages and extracellularly in the lamina propria; all 15 specimens that were negative for invasive bacteria on FISH were also negative on IHC. We found that IHC is a sensitive technique for the detection of invasive E. coli in dogs with granulomatous colitis.

Successful resolution of Escherichia coli associated granulomatous colitis (ECGC) is becoming a challenge due to the development of fluoroquinolone resistant Escherichia coli, which is associated with poor prognosis. Three dogs presented with signs of chronic colitis and were diagnosed with ECGC. All three were initially treated with enrofloxacin and trimethoprim-sulfamethoxazole, without clinical improvement. Despite the fact that culture and susceptibility testing results demonstrate resistance to fluoroquinolone and trimethoprim-sulfamethoxazole, the addition of amikacin fully resolved the clinical signs in all three cases. This case series describes the clinical presentation, diagnostic findings, and successful treatment of three dogs with fluoroquinolone-resistant ECGC. It suggests an alternative strategy for multidrug-resistance ECGC patients. Further investigations are required to confirm the efficacy of and to determine the molecular mechanisms underpinning the apparent success of aminoglycoside antibiotic combinations for treatment of ECGC.