Proposal for rational antibacterial use in the diagnosis and treatment of dogs with chronic diarrhoea

Chronic diarrhoea is a frequent complaint in canine practice and the diagnostic path is often characterised by numerous diagnostic tests and stepwise empirical treatments, often applied before gastrointestinal endoscopy/mucosal biopsies. These include dietary interventions (novel protein, hydrolysed protein diet), parasiticides and still, in many cases, antibacterials. Indiscriminate use of antibacterial drugs risks detrimental consequences for both the individual patient (antimicrobial resistance, long‐term disruption of intestinal bacterial populations, potential worsening of gastrointestinal signs) and the general public. For that reason, in this Perspective essay we advocate use of antibacterials only after histopathologic evaluation of gastrointestinal biopsies or, for those cases in which endoscopy is not possible, after other therapeutic trials, such as diet/pre‐probiotics or anti‐inflammatory drugs have proven unsuccessful. They should be reserved, after appropriate dietary trials, for those canine chronic diarrhoeic patients with signs of true primary infection (i.e. signs of systemic inflammatory response syndrome or evidence of adherent‐invasive bacteria) that justify antibacterial use.

Faecal microbiota in dogs with multicentric lymphoma

Malignant lymphoma B-cell type is the most common canine haematopoietic malignancy. Changes in intestinal microbiota have been implicated in few types of cancer in humans. The aim of this prospective and case-control study was to determine differences in faecal microbiota between healthy control dogs and dogs with multicentric lymphoma. Twelve dogs affected by multicentric, B-cell, stage III-IV lymphoma, and 21 healthy dogs were enrolled in the study. For each dog, faecal samples were analysed by Illumina sequencing of 16S rRNA genes and quantitative PCR (qPCR) for selected bacterial groups. Alpha diversity was significant lower in lymphoma dogs. Principal coordinate analysis plots showed different microbial clustering (P = .001) and linear discriminant analysis effect size revealed 28 differentially abundant bacterial groups in lymphoma and control dogs. The qPCR analysis showed significant lower abundance of Faecalibacterium spp. (q < .001), Fusobacterium spp. (q = .032), and Turicibacter spp. (q = .043) in dogs with lymphoma compared with control dogs. On the contrary, Streptococcus spp. was significantly higher in dogs with lymphoma (q = .041). The dysbiosis index was significantly higher (P < .0001) in dogs with lymphoma. In conclusion, both sequencing and qPCR analyses provided a global overview of faecal microbial communities and showed significant differences in the microbial communities of dogs presenting with multicentric lymphoma compared with healthy control dogs.

Effects of a probiotic (SLAB51™) on clinical and histologic variables and microbiota of cats with chronic constipation/megacolon: a pilot study

Chronic constipation (CC) and idiopathic megacolon (IMC) occur frequently in cats. The aim of the study was to investigate the effects of a multi-strain probiotic (SLAB51™) in constipated cats (n=7) and in patients with megacolon and constipation (n=3). Ten pet cats with a diagnosis of chronic constipation, non-responsive to medical management received orally 2×10¹¹ bacteria daily for 90 days. For microbiota analysis, selected bacterial groups were analysed by qPCR. Histological samples in megacolons were evaluated for interstitial cells of Cajal (ICC), enteric neurons, and neuronal apoptosis. Biopsies were compared at baseline (T0) and after the end of treatment (T1), and with those obtained from healthy control tissues (archived material from five healthy cats). Constipated cats displayed significantly lower ICC, and cats with idiopathic megacolon had significantly more apoptotic enteric neurons than controls. After treatment with SLAB51™, significant decreases were observed for feline chronic enteropathy activity index (FCEAI) (P=0.006), faecal consistency score, and mucosal histology scores (P<0.001). In contrast, a significant increase of ICC was observed after probiotic therapy. Lactobacillus spp. and Bacteroidetes were increased significantly after treatment (comparing constipated cats before and after treatment, and control healthy cats to constipated cats after treatment), but no other differences in microbiota were found between healthy controls and constipated cats. Treatment with SLAB51™ in cats with chronic constipation and idiopathic megacolon showed significant clinical improvement after treatment, and histological parameters suggest a potential anti-inflammatory effect of SLAB51™, associated with a reduction of mucosal infiltration, and restoration of the number of interstitial cells of Cajal.

Effects of probiotic bacteria on mucosal polyamines levels in dogs with IBD and colonic polyps: a preliminary study

Spermine (SPM) and its precursor putrescine (PUT), regulated by ornithine decarboxylase (ODC) and diamino-oxidase (DAO), are polyamines required for cell growth and proliferation. Only a few studies have investigated the anti-inflammatory and tumour inhibitory properties of probiotics on mucosal polyamine levels. We investigated the effects of a high concentration multistrain probiotic for human use on colonic polyamine biosynthesis in dogs. Histological sections (inflammatory bowel disease, n=10; polyposis, n=5) were assessed after receiving 112 to 225×10⁹ lyophilised bacteria daily for 60 days at baseline (T0) and 30 days after treatment end (T90). Histology scores, expression of PUT, SPM, ODC and DAO, and a clinical activity index (CIBDAI) were compared at T0 and T90. In polyps, cellular proliferation (Ki-67 expression), and apoptosis (caspase-3 protein expression) were also evaluated. After treatment, in inflammatory bowel disease significant decreases were observed for CIBDAI (P=0.006) and histology scores (P<0.001); PUT, SPM and ODC expression increased (P<0.01). In polyps, a significant decrease in polyamine levels, ODC activity, and Ki-67, and a significant increase in caspase-3 positivity and DAO expression (P=0.005) was noted. Our results suggest potential anti-proliferative and anti-inflammatory effects of the probiotic mixture in polyps and inflammation, associated with reduced mucosal infiltration and up-regulation of PUT, SPM, and ODC levels.

Colonic cyst in a cat presenting recurrent constipation and abdominal pain

A 5-year-old domestic short-haired spayed female cat was presented for abdominal pain and suspended defecation. Abdominal radiographs confirmed constipation; abdominal ultrasonography showed a cystic oval structure attached to the colon. The structure exhibited a well-defined wall, composed of three layers. Its content was mildly echogenic and inhomogeneous. Laparotomy was performed and complete resection of the structure, and of part of the colon, was required (end-to-end anastomosis). Histopathology confirmed the structure to be a cystic formation of the colon with some areas of mucosal metaplasia. However the question whether the cystic structure was consistent with an intestinal duplication cyst - which is the most likely type of cyst in this particular case - a Meckel's diverticulum remnant, a vitelline duct cyst or a cystic diverticulum of the colon could not be resolved. Postoperatively, no further other episode of constipation occurred.