PMC7644445_01
Images from the initial abdominal ultrasound (A,B) and endoscopy (C-E). (A) Jejunal ulcerations with gas inclusions (red arrows). (B) Enlarged jejunal lymph node with gas (red arrows). (C,D) Colonic mucosa showing marked generalized hyperemia with small (~1 cm diameter) and diffuse colonic circular erosions. (E) Ileum mucosa with hyperemia and striations.
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F1
Intestinal wall layering was intact, but numerous gas artifacts extended into the jejunal submucosa, interpreted as deep ulcers (Figure 1A). Evidence of moderate local steatitis was identified along with jejunal lymph node enlargement (13 mm) and intracapsular gas (Figure 1B). The ileum appeared firm with hyperemic striations, but no gross mucosal erosions (Figures 1C-E).
Timeline of the dog's clinical course and treatments. Serum albumin values are depicted in the orange line; the reference interval indicated by the faint orange background. The dog's body weight is depicted in the blue line. Pink stars indicate cobalamin injections. Details about the products and dosages can be found in the main text.
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F2
Body weight remained stable over the first 4 days then dropped, later accompanied by a further decrease in the serum albumin (Table 1 and Figure 2) at day 7 of hospitalization. Metronidazole was administered for a total of 21 days and dexamethasone was switched to oral prednisolone (2 mg/kg/day) on day 14 (Figure 2). Fecal characteristics improved and the overall CIBDAI reduced to 4 alongside an increased serum albumin on day 18 (Table 1 and Figure 2), when the dog was discharged. Oral enrofloxacin was continued for a total of 6 weeks (Figure 2), as recommended for E.coli associated GC. Cobalamin (400 mug) was administered parenterally weekly for 6 weeks, then again after a further month and retested by the RVS (Figure 2). On day 56, further weight loss was observed (Table 1 and Figure 2) and stools were reported as a cow-pat consistency, so a strict elimination diet was reinstated and a multi-strain probiotic blend6 was prescribed.
Histopathology of the colonic pinch biopsies. (A,B) H&E (20x) with intact crypts (A) and overlying fibrino-suppurative exudate, and areas of complete effacement of normal architecture (B) with inflammation and marked fibroplasia and neovascularization. (C) PAS (20x) with no PAS positive macrophages. (D) PAS (40x) stained colon from a dog with E.coli-associated GC with PAS positive macrophages for comparative purposes.
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F3
The main abnormalities were a moderate diffuse, chronic-active, and mildly eosinophilic ileitis, and marked diffuse, subacute, ulcerative colitis with an overlying fibrino-suppurative exudate, marked fibroplasia, and neovascularisation (Figures 3A,B). GC (Figures 3C,D); and Grocott's methenamine silver for fungi, protozoa, or prototheca algae; both were negative (Figure 4A). Gram-staining identified surface or mucosal exudate gram-positive bacteria (Figure 4B).
Histochemistry and FISH analysis of colonic biopsies. (A) Grocott stained section (40x) with no evidence of fungal elements. (B) Gram stain (60x) section of the overlying colonic fibrino-suppurative exudate, showing Gram+ve bacteria. (C,D) FISH of mucosa with oligonucleotide probes against Eubacteria (C) (Cy3-EUB-338-red / 6-FAM- Non-EUB 338 -green) and Enterococcus
(D) (Cy3-Enterococcus-red / 6-FAM- Non-EUB-338 -green) reveals a cluster of invasive intracellular Enterococcus spp. DAPI nuclear DNA (blue) counter-stain.
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F4
GC (Figures 3C,D); and Grocott's methenamine silver for fungi, protozoa, or prototheca algae; both were negative (Figure 4A). Gram-staining identified surface or mucosal exudate gram-positive bacteria (Figure 4B). Specific probes were negative for E.coli but confirmed an intramucosal Enterococcus spp. (Figures 4C,D).