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.

Effects of doxycycline on haematology, blood chemistry and peripheral blood lymphocyte subsets of healthy dogs and dogs naturally infected with Ehrlichia canis

Canine monocytic ehrlichiosis (CME), caused by Ehrlichia canis, is a vector-borne disease with a worldwide distribution. It has been proposed that the pathogenesis, clinical severity and outcome of disease caused by Ehrlichia spp. can be attributed to the immune response rather than to any direct rickettsial effect. Moreover, doxycycline, the antimicrobial of choice for the treatment of CME, has immunomodulatory and anti-inflammatory properties associated with blood leukocyte proliferation function, cytokine synthesis, and matrix metalloproteinase activity. In order to assess the potential effects of doxycycline, dependent and independent of its antimicrobial activity, the present study compared changes in haematology, blood chemistry and circulating lymphocyte subpopulations in 12 healthy dogs and 20 dogs with CME after doxycycline therapy. Some changes were recorded only in the CME affected dogs, probably due to the antimicrobial effect of doxycycline. However, increases in mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, platelet count and α2-globulins, and decreased plasma creatinine were observed in both healthy and CME affected dogs. The absolute count of B lymphocytes (CD21(+)) increased initially, but then decreased until the end of the study period in both groups. A potential effect of doxycycline unrelated to its antimicrobial activity against E. canis is suggested, taking into account the results observed both in healthy dogs and in dogs with CME.

Canine gastric carcinoma: immunohistochemical expression of cell cycle proteins (p53, p21, and p16) and heat shock proteins (Hsp27 and Hsp70)

Immunohistochemical staining for cell cycle proteins and heat shock proteins was performed on 17 canine gastric carcinomas. The immunoexpression of p53, p21, p16, Hsp27, and Hsp70 was investigated. A study was conducted to determine the histological type and parameters related to tumor malignancy. Possible associations and trends were assessed between the immunoexpression of each protein and tumor type as well as specific parameters of malignancy. High intratumor frequency of cellular p53 immunostaining was observed (61.96% average), but lower frequencies of p21 and p16 expression were present (34.65% and 10.41%, respectively). The p53 overexpression was associated with tumor infiltration (P = .0258). Expression of p21 was lower in undifferentiated carcinomas, and the loss of expression was associated with histopathological parameters characteristic of a poor prognosis such as lymphatic vessel invasion (P = .0258). The lack of p16 immunoreactivity was related to histopathological characteristics of malignancy such as the presence of evident and multiple nucleoli (P = .0475). In contrast, deep tumor infiltration was observed in those carcinomas with a high p16 index (P = .0475). Hsp70 appeared to be overexpressed in all gastric neoplasms included in this study. This is in contrast to Hsp27, because a group of tumors showed complete lack of Hsp27 immunoexpression, whereas the others displayed extensive Hsp27 immunostaining. The differences in Hsp27 did not correlate with any of the histopathological parameters, but Hsp27 immunoexpression was higher in the undifferentiated carcinoma. No significant differences in the expression of the proteins were found in canine gastric carcinomas according to their histological type. These findings may be useful for establishing a prognosis for canine gastric carcinoma.

Evaluation of Clinical, Macroscopic, and Histopathologic Response to Treatment in Nonhypoproteinemic Dogs with Lymphocytic-Plasmacytic Enteritis

BACKGROUND

Lymphocytic-plasmacytic enteritis (LPE) is a common cause of chronic vomiting and diarrhea in dogs. However, little information is available about endoscopic or histopathologic improvement after therapy in dogs with LPE.

HYPOTHESIS

The objective was to study the clinical, endoscopic, and histopathologic evolution of LPE during and after immunosuppressive treatment with prednisone and metronidazole. Most dogs also were treated symptomatically with metoclopramide and cimetidine.

ANIMALS

Sixteen dogs with LPE and normal serum protein concentrations diagnosed at the Veterinary Medical Teaching Hospital of the Complutense University of Madrid were monitored during and after drug treatment. The control group consisted of 9 dogs that had no gastrointestinal signs for the preceding 12 months.

METHODS

In this prospective clinical treatment trial, clinical, endoscopic, and histopathologic scores were evaluated to describe disease evolution during conventional therapy. Dogs with LPE were monitored for 120 days from the start of treatment. Re-evaluation was performed on post-treatment days 30, 60, 90 (end of treatment), and 120.

RESULTS

The average disease activity index observed in our study fell progressively from its initial value, and the decrease between consecutive re-evaluations was statistically significant until day 60 (P = .04). Our results indicate that 75% of the animals revealed improvement of endoscopic gastric lesions (defined as a reduction of the endoscopic score) after treatment, and 75% exhibited improvement of endoscopic duodenal lesions. Statistical analysis of the data revealed significant differences between pre- and post-treatment gastric and duodenal macroscopic endoscopic lesions (P < .05). On the other hand, treatment did not lead to any significant changes in the severity of the gastric and duodenal histopathologic lesions of the affected dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Treatment of nonhypoproteinemic dogs with LPE led to clinical and endoscopic improvement, but histopathologic lesions were unchanged during therapy.

Pharmacological and dietary treatment of canine malabsorption syndrome: a retrospective study of 17 clinical cases

The present study deals with the symptomatology, diagnosis (by means of gastroduodenoscopy and biopsy) and response to a combined dietary/immunosuppressive pharmacological treatment of 17 dogs with malabsorption syndrome. Clinical signs, body weight and serum protein levels evolved favourably in all individuals included in this study during the 150 days following initiation of treatment.