Endoscopically visualized lesions, histologic findings, and bacterial invasion in the gastrointestinal mucosa of dogs with acute hemorrhagic diarrhea syndrome

Safety profile and effects on the peripheral immune response of fecal microbiota transplantation in clinically healthy dogs

BACKGROUND

Fecal microbiota transplantation (FMT) is increasingly used for gastrointestinal and extra-gastrointestinal diseases in veterinary medicine. However, its effects on immune responses and possible adverse events have not been systematically investigated.

HYPOTHESIS/OBJECTIVES

Determine the short-term safety profile and changes in the peripheral immune system after a single FMT administration in healthy dogs.

ANIMALS

Ten client-owned, clinically healthy dogs as FMT recipients, and 2 client-owned clinically healthy dogs as FMT donors.

METHODS

Prospective non-randomized clinical trial. A single rectal enema of 5 g/kg was given to clinically healthy canine recipients. During the 28 days after FMT administration, owners self-reported adverse events and fecal scores. On Days 0 (baseline), 1, 4, 10, and 28 after FMT, fecal and blood samples were collected. The canine fecal dysbiosis index (DI) was calculated using qPCR.

RESULTS

No significant changes were found in the following variables: CBC, serum biochemistry, C-reactive protein, serum cytokines (interleukins [IL]-2, -6, -8, tumor necrosis factor [TNF]-α), peripheral leukocytes (B cells, T cells, cluster of differentiation [CD]4+ T cells, CD8+ T cells, T regulatory cells), and the canine DI. Mild vomiting (n = 3), diarrhea (n = 4), decreased activity (n = 2), and inappetence (n = 1) were reported, and resolved without intervention.

CONCLUSIONS AND CLINICAL IMPORTANCE

Fecal microbiota transplantation did not significantly alter the evaluated variables and recipients experienced minimal adverse events associated with FMT administration. Fecal microbiota transplantation was not associated with serious adverse events, changes in peripheral immunologic variables, or the canine DI in the short-term.

Fecal microbiome composition and diversity of cryopreserved canine stool at different duration and storage conditions

Fresh-frozen stool banks intended for humans with gastrointestinal and metabolic disorders have been recently established and there are ongoing efforts to establish the first veterinary fresh-frozen stool bank. Fresh frozen stored feces provide an advantage of increased availability and accessibility to high-quality optimal donor fecal material. The stability of frozen canine feces regarding fecal microbiome composition and diversity has not been reported in dogs, providing the basis for this study. We hypothesized that fecal microbial composition and diversity of healthy dogs would remain stable when stored at -20°C and -80°C for up to 12 months compared to baseline samples evaluated before freezing. Stool samples were collected from 20 apparently healthy dogs, manually homogenized, cryopreserved in 20% glycerol and aliquoted, frozen in liquid nitrogen and stored at -20°C or -80°C for 3, 6, 9, and 12 months. At baseline and after period of storage, aliquots were thawed and treated with propidium monoazide before fecal DNA extraction. Following long-read 16S-rRNA amplicon sequencing, bacterial community composition and diversity were compared among treatment groups. We demonstrated that fresh-frozen canine stools collected from 20 apparently healthy dogs could be stored for up to 12 months at -80°C with minimal change in microbial community composition and diversity and that storage at -80°C is superior to storage at -20°C. We also found that differences between dogs had the largest effect on community composition and diversity. Relative abundances of certain bacterial taxa, including those known to be short-chain fatty acid producers, varied significantly with specific storage temperatures and duration. Further work is required to ascertain whether fecal donor material that differs in bacterial community composition and diversity across storage conditions and duration could lead to differences in clinical efficacy for specific clinical indications of fecal microbiota transplantation.

Fecal Protein Profile in Eight Dogs Suffering from Acute Uncomplicated Diarrhea before and after Treatment

Acute diarrhea is a very frequent condition affecting dogs; nevertheless, little is known about what happens in the GI tract during such conditions. Proteomics allows the study of proteins present in a specific biologic substrate, and fecal proteomic investigations have been recently implemented to study GI diseases in dogs. In the present study, the fecal protein profiles of eight dogs suffering from acute uncomplicated diarrhea at the time of inclusion was investigated for the first time, and then the same patients were followed, replicating two further evaluations at two subsequent time points (after 2 and 14 days from the first presentation), with the aim of gaining possible new insights regarding the pathologic changes in the gastrointestinal environment during such conditions. Two-dimensional gel electrophoresis (2-DE) was performed, followed by mass spectrometry. Nine spots, corresponding to four (groups of) proteins (i.e., albumin, alkaline phosphatase, chymotrypsin-C-like, and some immunoglobulins), showed significant differences at two or more of the three time points investigated, almost all behaving similarly and decreasing at T1 (2 days after the onset of the condition) and significantly increasing at T2 (14 days after the onset), mainly evidencing a reaction of the organism. Further studies including a greater number of patients and possibly different techniques are needed to confirm the present findings.

Clinical response in dogs with acute hemorrhagic diarrhea syndrome following randomized probiotic treatment or fecal microbiota transplant

Probiotics and fecal microbiota transplants (FMTs) are two microbiome-targeted therapies that have been investigated for use in gastrointestinal diseases associated with dysbiosis. The aim of this study was to compare the effects of an oral multi-strain probiotic and enema-administered FMTs on clinical signs and serum lipopolysaccharide in dogs with acute hemorrhagic diarrhea syndrome (AHDS). A total of 18 client-owned dogs with a diagnosis of AHDS were enrolled in a randomized, blinded study at the time of hospital admission. The dogs were randomized into two groups: the probiotic group received a daily oral probiotic (200 × 10⁹ CFU/10kg q 24 h) for 14 days and a single sham enema; the FMT group received a single FMT via retention enema (10 mL/kg) and placebo oral capsule for 14 days. All dogs received concurrent standard-of-care therapy, including intravenous fluids and anti-emetics; no dogs received antimicrobials. The fecal score, disease severity scores, and serum lipopolysaccharide were measured on days 0, 3, and 14. Fourteen of eighteen enrolled dogs completed the study (n = 9 probiotics; n = 5 FMT). Lipopolysaccharide decreased on days 3 and 14 from baseline and correlated with fecal and disease severity scores. There was no difference in the duration or severity of clinical signs in dogs with AHDS following an enema-administered FMT compared to probiotic treatment. Further evaluation of serum lipopolysaccharide as a marker of disease severity and recovery is warranted.

C-reactive protein as a tool for monitoring response to treatment in dogs with acute hemorrhagic diarrhea syndrome

Objectives

C-reactive protein (CRP) is an established marker for systemic inflammation in dogs that is especially elevated in dogs with sepsis. Some dogs with acute hemorrhagic diarrhea syndrome (AHDS) develop bacterial translocation and consequent sepsis during hospitalization. This study aimed to evaluate the course of CRP plasma concentrations during hospitalization and its correlation with clinical and other laboratory variables in dogs with AHDS.

Methods

In this prospective, observational study, CRP was evaluated on days 0, 1, 2, and 3 in 27 client-owned dogs who presented with AHDS. Clinical examination data, blood pressure, acute patient physiologic and laboratory evaluation (APPLE) full and APPLE fast scores, and canine hemorrhagic diarrhea severity (CHDS) index were measured on the same days to evaluate the severity of the disease.

Results

Twenty-five of the 27 dogs were discharged from hospital. Nineteen dogs received antimicrobial treatment due to sepsis or neutropenia. CRP values were mildly elevated on day 0 (median 27.3 mg/L; 1.0-125.8 mg/L) and markedly elevated on day 1 (median 88.9 mg/L; 1.4-192.7 mg/L). CRP concentrations decreased gradually over the following days. Moreover, CRP concentrations correlated moderately with albumin, leucocyte count, neutrophil count, and APPLE full and fast scores, but not with antimicrobial treatment.

Conclusion and relevance

CRP concentrations were significantly elevated in patients with AHDS. In this study population, CRP did not help in detecting the requirement of antimicrobial treatment in dogs with AHDS. Nevertheless, as CRP can monitor the response to treatment, regular analysis can guide treatment.

Evaluation of quick sequential organ failure scores in dogs with severe sepsis and septic shock

OBJECTIVES

To evaluate the prognostic utility of the quick sequential organ failure assessment score in dogs with severe sepsis and septic shock presenting to an emergency service, and evaluate the clinical value of the quick sequential organ failure assessment score to predict severe sepsis and septic shock.

MATERIALS AND METHODS

The quick sequential organ failure assessment score was calculated by evaluating respiratory rate (>22 breaths per minute), arterial systolic blood pressure (≤100 mmHg) and altered mentation. The quick sequential organ failure assessment scores with respiratory rate cut-offs of greater than 22, greater than 30 and greater than 40 were compared. Cases were defined as dogs presented to the emergency room and met at least 2 systemic inflammatory response syndrome criteria, had documented infection, and at least one organ dysfunction. A control population of dogs included animals with non-infectious systemic inflammatory response syndrome.

RESULTS

Forty-five dogs with severe sepsis and septic shock and 45 dogs with non-infectious systemic inflammatory response syndrome were included in the final analysis. The quick sequential organ failure assessment provided poor discrimination between survivors and non-survivors for severe sepsis and septic shock (area under receiving operating characteristic curve, 0.51; 95% confidence interval, 0.35 to 0.67). Discrimination remained poor when quick sequential organ failure assessment greater than 30 and quick sequential organ failure assessment greater than 40 scores were calculated (area under receiving operating characteristic curve, 0.56; 95% confidence interval, 0.39 to 0.72, and 0.54; 95% confidence interval, 0.36 to 0.71). The quick sequential organ failure assessment of at least 2, quick sequential organ failure assessment greater than 30 of at least 2 and quick sequential organ failure assessment greater than 40 of at least 2 produced sensitivity and specificity to detect severe sepsis and septic shock of 66.7% and 64.5%, 62.2% and 71.1%, 44.4% and 80%, respectively.

CONCLUSION AND CLINICAL SIGNIFICANCE

Scoring systems utilised in emergency rooms should have high sensitivity to reduce missed sepsis cases and treatment delays. The use of the quick sequential organ failure assessment for severe sepsis and septic shock demonstrated poor mortality prediction and low sensitivity to detect canine patients with severe sepsis and septic shock and should not be used alone when screening for sepsis.

Frequency of signs of chronic gastrointestinal disease in dogs after an episode of acute hemorrhagic diarrhea

BACKGROUND

Acute enteropathy is a trigger of chronic gastrointestinal (GI) disease in humans.

OBJECTIVE

To report the prevalence of and explore possible risk factors for signs of chronic GI disease in dogs after an episode of acute hemorrhagic diarrhea (AHD).

ANIMALS

One hundred and fifty-one dogs, 80 dogs with a historical diagnosis of AHD, 71 control dogs with no history of AHD.

METHODS

In this retrospective longitudinal study, data were collected from dogs with a historical diagnosis of AHD and healthy controls matched by breed, age and sex, aged between 1 year and 15 years of age, for which a follow-up of at least 12 months after enrolment was available. Dog owners responded to a questionnaire to determine the history of signs of chronic GI disease.

RESULTS

There was a higher prevalence of signs of chronic GI disease in the dogs with a previous episode of AHD compared to control dogs (AHD 28%; controls 13%; P = .03; odds ratio = 2.57; confidence interval [CI] 95% 1.12-6.31) over a similar observation time (median 4 years; range, 1-12 years).

CONCLUSIONS AND CLINICAL IMPORTANCE

Severe intestinal mucosal damage and associated barrier dysfunction might trigger chronic GI disease later in life.

An Official Outbreak Investigation of Acute Haemorrhagic Diarrhoea in Dogs in Norway Points to Providencia alcalifaciens as a Likely Cause

An outbreak investigation was initiated in September 2019, following a notification to the Norwegian Food Safety Authority (NFSA) of an unusually high number of dogs with acute haemorrhagic diarrhoea (AHD) in Oslo. Diagnostic testing by reporting veterinarians had not detected a cause. The official investigation sought to identify a possible common cause, the extent of the outbreak and prevent spread. Epidemiological data were collected through a survey to veterinarians and interviews with dog owners. Diagnostic investigations included necropsies and microbiological, parasitological and toxicological analysis of faecal samples and food. In total, 511 dogs with acute haemorrhagic diarrhoea were registered between 1 August and 1 October. Results indicated a common point source for affected dogs, but were inconclusive with regard to common exposures. A notable finding was that 134 of 325 faecal samples (41%) cultured positive for Providencia alcalifaciens. Whole genome sequencing (WGS) of 75 P. alcalifaciens isolates from 73 dogs revealed that strains from 51 dogs belonged to the same WGS clone. Findings point to P. alcalifaciens as implicated in the outbreak, but investigations are needed to reveal the pathogenic potential of P. alcalifaciens in dogs and its epidemiology.

Enteric Organisms Detected in Feces of Dogs With Bloody Diarrhea: 45 Cases

Bloody diarrhea is a common condition in dogs, but studies evaluating the enteropathogens involved specifically in adult dogs are scarce. In the present study, stool samples from 45 adult dogs with bloody diarrhea were evaluated for the four enteric organisms mainly reported in these cases: canine parvovirus type 2 (CPV-2), Clostridioides difficile, Clostridium perfringens, and Salmonella spp. In addition, the samples were also tested for coronavirus, rotavirus, Giardia spp., and Escherichia coli pathotypes to provide a better understanding of possible co-occurrence. Vaccination status, diet, and clinical outcome were also obtained when available. CPV-2b was identified in 17 dogs (37.8%), being the most frequent cause of bloody diarrhea, including completely vaccinated adult dogs. Toxigenic C. difficile and C. perfringens netF⁺ were detected in 6 (13.3%) and 5 (11.1%) dogs, in some cases in a co-occurrence with other enteric organisms. Three fatal cases of salmonellosis were identified in dogs fed a raw meat-based diet, raising the risks associated with this increasing practice.

Changes in the fecal microbiota in dogs with acute hemorrhagic diarrhea during an outbreak in Norway

Background

A severe form of acute hemorrhagic diarrhea syndrome (AHDS) occurred in dogs in the Oslo region of Norway during autumn 2019.

Objectives

To characterize the fecal microbiota of dogs with AHDS during the outbreak and compare it to that of healthy dogs from the same period and before the outbreak.

Animals

Dogs with AHDS (n = 50), dogs with nonhemorrhagic diarrhea (n = 3), and healthy dogs (n = 11) were sampled during the outbreak. In addition, 78 healthy dogs from the same region were sampled before the outbreak between 2017 and 2018.

Methods

Retrospective case‐control study. The fecal microbiotas were characterized using 16S rRNA gene amplicon sequencing.

Results

Dogs with AHDS had significantly different microbiota composition (R² = .07, P < .001) and decreased intestinal diversity relative to healthy dogs from the outbreak period (median, 2.7; range, 0.9‐3.5 vs median, 3.2; range, 2.6‐4.0; P < .001). The microbiota in dogs with AHDS was characterized by a decrease of Firmicutes and an outgrowth of Proteobacteria, with increased numbers of Clostridium perfringens and Providencia spp. Among the Providencia spp., 1 showed 100% sequence identity with a Providencia alcalifaciens strain that was cultivated and isolated from the same outbreak. No Providencia spp. was found in healthy dogs sampled before the outbreak.

Conclusions and Clinical Importance

Dogs with AHDS had marked changes in fecal microbiota including increased numbers of Providencia spp. and C. perfringens, which may have contributed to the severity of this illness.

One dog's waste is another dog's wealth: A pilot study of fecal microbiota transplantation in dogs with acute hemorrhagic diarrhea syndrome

Canine acute hemorrhagic diarrhea syndrome (AHDS) has been associated in some studies with Clostridioides perfringens overgrowth and toxin-mediated necrosis of the intestinal mucosa. We aimed to determine the effect of a single fecal microbiota transplantation (FMT) on clinical scores and fecal microbiomes of 1 and 7 dogs with AHDS from New Zealand and South Africa. We hypothesized that FMT would improve AHDS clinical scores and increase microbiota alpha-diversity and short-chain fatty acid (SCFA)-producing microbial communities’ abundances in dogs with AHDS after FMT. We sequenced the V3-V4 region of the 16S-rRNA gene in the feces of AHDS FMT-recipients and sham-treated control dogs, and their healthy donors at admission, discharge, and 30 days post-discharge. There were no significant differences in median AHDS clinical scores between FMT-recipients and sham-treated controls at admission or discharge (P = 0.22, P = 0.41). At admission, the Shannon diversity index (SDI) was lower in AHDS dogs than healthy donors (P = 0.002). The SDI did not change from admission to 30 days in sham-treated dogs yet increased in FMT-recipients from admission to discharge (P = 0.04) to levels not different than donors (P = 0.33) but significantly higher than sham-treated controls (P = 0.002). At 30 days, the SDI did not differ between FMT recipients, sham-treated controls, and donors (P = 0.88). Principal coordinate analysis of the Bray-Curtis index separated post-FMT and donor dogs from pre-FMT and sham-treated dogs (P = 0.009) because of increased SCFA-producing genera’s abundances after FMT. A single co-abundance subnetwork contained many of the same OTUs found to be differentially abundant in FMT-recipients, and the abundance of this module was increased in FMT-recipients at discharge and 30 days, compared to sham-treated controls. We conclude in this small pilot study FMT did not have any clinical benefit. A single FMT procedure has the potential to increase bacterial communities of SCFA-producing genera important for intestinal health up to 30 days post-FMT.

Prevalence of Clostridium perfringens alpha toxin and enterotoxin in the faeces of dogs with acute haemorrhagic diarrhoea syndrome

OBJECTIVES

To investigate the prevalence of Clostridium perfringens alpha toxin encoding gene and C. perfringens enterotoxin encoding gene in dogs with acute haemorrhagic diarrhoea syndrome.

MATERIALS AND METHODS

Retrospective study looking at the prevalence of C. perfringens alpha toxin and C. perfringens enterotoxin in the faeces of three groups of dogs - those with acute haemorrhagic diarrhoea syndrome (n = 16), those with haemorrhagic diarrhoea from another cause (n = 17) and those without haemorrhagic diarrhoea (n = 10). Correlation between the presence of C. perfringens alpha toxin and/or C. perfringens enterotoxin and Acute Patient Physiological and Laboratory Evaluation_fast scores, acute haemorrhagic diarrhoea index scores and length of hospitalisation in dogs with acute haemorrhagic diarrhoea syndrome was assessed.

RESULTS

Prevalence of C. perfringens alpha toxin was not higher in dogs with acute haemorrhagic diarrhoea syndrome (43.75%) than dogs with haemorrhagic diarrhoea from another cause (58.82%) (difference in prevalence 15.07%; 95% CI -37% to 32%) or in dogs without haemorrhagic diarrhoea (60%) (difference in prevalence 16.25%; 95% CI -4% to 36%). Dogs with acute haemorrhagic diarrhoea syndrome did not have a significantly higher prevalence of C. perfringens enterotoxin (18.75%) compared to dogs without haemorrhagic diarrhoea (11.76%) (difference in prevalence 6.99%; 95% CI -18% to 32%). Prevalence of C. perfringens enterotoxin was similar in dogs with acute haemorrhagic diarrhoea syndrome and dogs without haemorrhagic diarrhoea (20%) (difference in prevalence 1.25% 95% CI -33% to 30%). The presence of C. perfringens alpha toxin did not correlate with increased Acute Patient Physiological and Laboratory Evaluation_fast scores, acute haemorrhagic diarrhoea index scores or length of hospitalisation in dogs with acute haemorrhagic diarrhoea syndrome.

CLINICAL SIGNIFICANCE

This study does not demonstrate increased prevalence of C. perfringens alpha toxin or C. perfringens enterotoxin in dogs with acute haemorrhagic diarrhoea syndrome compared to dogs with haemorrhagic diarrhoea from another cause or dogs without haemorrhagic diarrhoea.

A retrospective study of 237 dogs hospitalized with suspected acute hemorrhagic diarrhea syndrome: Disease severity, treatment, and outcome

BACKGROUND

Few studies have investigated management and outcome in dogs with acute hemorrhagic diarrhea syndrome (AHDS), and there is a paucity of data on dogs with concurrent signs of sepsis.

OBJECTIVES

To report outcome in dogs with suspected AHDS according to disease severity and antimicrobial treatment, and to evaluate effect of fluid resuscitation on clinical criteria.

ANIMALS

Two hundred thirty-seven dogs hospitalized with suspected AHDS.

METHODS

Retrospective study based on medical records. Disease severity was evaluated using AHDS index, systemic inflammatory response syndrome (SIRS) criteria, and serum C-reactive protein (CRP) according to 3 treatment groups: No, 1, or 2 antimicrobials.

RESULTS

Sixty-two percent received no antimicrobials, 31% received 1 antimicrobial, predominantly aminopenicillins, and 7% received 2 antimicrobials. At admission, median AHDS index was 13 (interquartile range, 11-15), which decreased significantly after the first day's hospitalization (P < .001) for all groups. Compared with no antimicrobials (7%), more dogs had ≥2 SIRS criteria in the antimicrobial groups (15% and 36%, respectively). C-reactive protein (CRP) correlated positively with AHDS index at hospitalization (P < .001). Across treatment groups, rehydration markedly reduced number of clinical SIRS criteria. Survival to discharge was 96%, lower for dogs receiving 2 antimicrobials (77%, P < .05).

CONCLUSIONS AND CLINICAL IMPORTANCE

The majority of dogs hospitalized with suspected AHDS improve rapidly with symptomatic treatment only, despite signs of systemic disease on initial presentation. The often-used SIRS criteria might be a poor proxy for identifying dogs with AHDS in need of antimicrobial treatment, in particular when hypovolemic. The role of CRP in clinical decision-making or prognostication warrants further investigation.

On the Variability of Microbial Populations and Bacterial Metabolites within the Canine Stool. An in-Depth Analysis

Simple Summary

The present study investigated for the first time the impact that different sampling points have on the abundance of microbial populations and metabolites within the canine stool. We found that inner stool subsamples resulted in higher concentrations of bacterial metabolites but not of microbial populations. These findings suggest that stool subsampling is unlikely to represent the canine microbiota and metabolome uniformly. We believe that complete homogenisation of the whole stool prior to analysis may improve the final outcome when investigating the canine gut microbiome.

Abstract

Canine faecal microbial populations and metabolome are being increasingly studied to understand the interplay between host and gut microbiome. However, the distribution of bacterial taxa and microbial metabolites throughout the canine stool is understudied and currently no guidelines for the collection, storage and preparation of canine faecal samples have been proposed. Here, we assessed the effects that different sampling points have on the abundance of selected microbial populations and bacterial metabolites within the canine stool. Whole fresh faecal samples were obtained from five healthy adult dogs. Stool subsamples were collected from the surface to the inner part and from three equally sized areas (cranial, central, caudal) along the length axis of the stool log. All samples were finally homogenised and compared before and after homogenisation. Firmicutes, Bacteroidetes, Clostridium cluster I, Lactobacillus spp., Bifidobacterium spp. and Enterococcus spp. populations were analysed, as well as pH, ammonia and short-chain fatty acids (SCFA) concentrations. Compared to the surface of the stool, inner subsamples resulted in greater concentrations of SCFA and ammonia, and lower pH values. qPCR assay of microbial taxa did not show any differences between subsamples. Homogenisation of faeces does not affect the variability of microbial and metabolome data. Although the distribution patterns of bacterial populations and metabolites are still unclear, we found that stool subsampling yielded contradictory result and biases that can affect the final outcome when investigating the canine microbiome. Complete homogenisation of the whole stool is therefore recommended.

Presence of nucleosomes in plasma and increased thrombin generation in dogs with acute and chronic gastroenteropathies

Neutrophil extracellular traps (NETs) which contain nucleosomes protect the host by eliminating extracellular pathogens. However, any inflammatory stimuli can activate NETs and eventually lead to an immune overreaction leading to autoimmune diseases and thrombosis. Acute/chronic gastroenteropathies(aGE/cGE) are prevalent in dogs, and are associated with a strong inflammatory component. The aim of this study was to investigate if dogs with aGE and cGE have increased concentrations of nucleosomes indicative of NETs formation, and whether increased concentrations of nucleosomes are associated with hypercoagulability determined by increased thrombin generation. Twenty-six dogs were enrolled. The dogs were healthy (n = 11), or presented with aGE(n = 7) or cGE(n = 8). Minimum database including CRP, APTT, PT and fibrinogen, was obtained from all dogs. Citrated plasma was batched and used for subsequent analyses. Nucleosome concentration was analysed using a Cell-Death Detection ELISA-kit and thrombin generation by a calibrated automated thrombogram assay. No statistical differences in nucleosome concentrations were present between the groups. Although a numerically increased concentration of nucleosomes where seen in dogs with aGE(median;range) (0.019 AU;0.003-0.088) and cGE(0.023 AU;0.011-0.256) compared to controls(0.007 AU;0.003-0.042). One dog with GI-lymphoma demonstrated a markedly increased concentration of nucleosomes (0.256 AU). Dogs with aGE showed increased thrombin generation by increased peak (p = 0.03) and endogenous thrombin potential (p = 0.03); and increased CRP (p = 0.001), fibrinogen (p = 0.0002) and prolonged APTT (p = 0.03) compared to controls. This proof of concept study demonstrates that dogs with aGE and cGE have presence of nucleosomes with marked increase in one dog with GI-lymphoma. Nucleosomes might be linked to haemostatic alterations in dogs with inflammatory and neoplastic diseases.

Acute Ulcerative Enterocolitis With Severe Protein Loss Due to Mucosal Invasion With Enterococcus spp. in a Dog With Exocrine Pancreatic Insufficiency: A Case Report

We describe an unusual case of severe acute protein-losing enteropathy in a dog, which presented with a systemic inflammatory response syndrome. This dog's condition could not be categorized as any well-known canine intestinal condition. Instead, components of several enteropathies like acute hemorrhagic diarrhea syndrome (AHDS), chronic inflammatory enteropathy (CIE), and ulcerative and granulomatous colitis were present. Thorough investigations identified concurrent exocrine pancreatic insufficiency (EPI) and hypocobalaminemia. On histopathology, marked diffuse chronic-active ileitis and ulcerative colitis with fibroplasia and neovascularization were present. Intestinal biopsy cultures identified E.coli and multiresistant Enterococcus spp. The latter was identified as mucosally invasive using fluorescent in situ hybridization (FISH). Protracted clinical signs following the acute presentation required intensive care including enteral and parenteral feeding for a successful outcome, but eventually stabilized with antibiotics and immunosuppressive doses of glucocorticoids. This case highlights a potentially previously unrecognized condition, suspected to be a form of CIE manifesting acutely after bacterial mucosal invasion. In this case, this might have been facilitated by EPI-induced dysbiosis. The use of FISH and mucosal culture in this context provided important clinical information and should be considered more frequently in CIE and non-responsive AHDS.

Catching a glimpse of the bacterial gut community of companion animals: a canine and feline perspective

Dogs and cats have gained a special position in human society by becoming our principal companion animals. In this context, efforts to ensure their health and welfare have increased exponentially, with in recent times a growing interest in assessing the impact of the gut microbiota on canine and feline health. Recent technological advances have generated new tools to not only examine the intestinal microbial composition of dogs and cats, but also to scrutinize the genetic repertoire and associated metabolic functions of this microbial community. The application of high-throughput sequencing techniques to canine and feline faecal samples revealed similarities in their bacterial composition, with Fusobacteria, Firmicutes and Bacteroidetes as the most prevalent and abundant phyla, followed by Proteobacteria and Actinobacteria. Although key bacterial members were consistently present in their gut microbiota, the taxonomic composition and the metabolic repertoire of the intestinal microbial population may be influenced by several factors, including diet, age and anthropogenic aspects, as well as intestinal dysbiosis. The current review aims to provide a comprehensive overview of the multitude of factors which play a role in the modulation of the canine and feline gut microbiota and that of their human owners with whom they share the same environment.

Acute Hemorrhagic Diarrhea Syndrome in Dogs

Acute hemorrhagic diarrhea syndrome is defined as sudden onset of severe bloody diarrhea frequently associated with vomiting, which results in severe, sometimes life-threatening dehydration. Although there is strong evidence that clostridial overgrowth and toxin release is responsible for the pathogenesis of the disease, the diagnosis is still based on exclusion of other causes for acute hemorrhagic diarrhea. With early and appropriate treatment, mainly based on fluid therapy, the prognosis is good and complications such as sepsis or severe hypoalbuminemia rarely occur.

Unravelling of nitric oxide signalling: A potential biomarker with multifaceted complex mechanism associated with canine inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD) is an important chronic condition associated with the infection affecting the gastrointestinal tract (G.I.) in dogs. Several factors' viz. gastrointestinal tract lymphoid tissue (GALT), permeability defects, genetic, ischemic, biochemical, psychosomatic disorders, infectious and parasitic agents, dietary allergies, and adverse drug reactions are associated with inflammatory bowel disease. The most noticeable clinical signs are vomiting, diarrhea, changes in appetite, weight loss, anorexia, ascites and peripheral edema. Nitric oxide (NO), a pleiotropic free radical messenger molecule plays an immense role in playing mucosal inflammation in the intestine through activation of NO synthase enzyme (iNOS). The complex mechanism associated with inflammation in the G.I. tract is also correlated with the expression of iNOS, enzymatic activity, and NO production. NO exerts a beneficial role in maintaining epithelial permeability as well as the immune response in acute colitis. But the excessive production of NO causes adverse effects. In the review, the author suggests that a complex phenomenon is associated with competing biochemical pathways triggered by NO through the regulation of mucosal inflammation in inflammatory bowel disease. This review is a unique compilation about the role of NO in the pathogenesis of inflammatory bowel disease of the dogs.

Bioinformatics analysis of NetF proteins for designing a multi-epitope vaccine against Clostridium perfringens infection

Clostridium perfringens is an important human and animal pathogen that is the primary causative agent of necrotizing enteritis and enterotoxemia in many types of animals. C. perfringens produces a variety of toxins, including NetF which may plays a crucial role in the pathogenesis of foal and canine necrotizing enteritis. In this study, we used several bioinformatics methods to analyze various aspects of the NetF proteins, including the physicochemical properties, secondary and tertiary structures, and the dominant B-cell and T-cell epitopes. The results showed that NetF protein was a stable and hydrophilic protein. The secondary structure of the NetF protein consisted of 2.62% alpha helixes, 6.56% beta turns, 38.69% extended strands and 52.13% random coils. Moreover, several potential B and T-cell epitopes were identified for NetF. In addition, the obtained findings from antigenicity and allergenicity evaluation remarked that this protein is immunogenic and non-allergen. Based on the results of Ramachandran plot, 94.22%, 5. 42%, and 0.36% of amino acid residues were incorporated in the favored, allowed, and outlier regions, respectively. This study provides a foundation for further investigations, and laid a theoretical basis for the development of an appropriate vaccine against C. perfringens infection.

NetF-producing Clostridium perfringens and its associated diseases in dogs and foals

The role of type A Clostridium perfringens in canine acute hemorrhagic diarrhea syndrome and foal necrotizing enteritis is poorly characterized. However, a highly significant association between the presence of novel toxigenic C. perfringens and these specific enteric diseases has been described. These novel toxigenic strains produce 3 novel putative toxins, which have been designated NetE, NetF, and NetG. Although not conclusively demonstrated, current evidence suggests that NetF is likely the major virulence factor in strains responsible for canine acute hemorrhagic diarrhea syndrome and foal necrotizing enteritis. NetF is a beta-pore-forming toxin that belongs to the same toxin superfamily as CPB and NetB toxins produced by C. perfringens. The netF gene is encoded on a conjugative plasmid that, in the case of netF, also carries another putative toxin gene, netE. In addition, these strains consistently also carry a cpe tcp-conjugative plasmid, and a proportion also carry a separate netG tcp-conjugative plasmid. The netF and netG genes form part of a locus with all the features of the pathogenicity loci of tcp-conjugative plasmids. The netF-positive isolates are clonal in origin and fall into 2 clades. Disease in dogs or foals can be associated with either clade. Thus, these are strains with unique virulence-associated characteristics associated with serious and sometimes fatal cases of important enteric diseases in 2 animal species.

The Role of the Canine Gut Microbiome and Metabolome in Health and Gastrointestinal Disease

The gut microbiome contributes to host metabolism, protects against pathogens, educates the immune system, and, through these basic functions, affects directly or indirectly most physiologic functions of its host. Molecular techniques have allowed us to expand our knowledge by unveiling a wide range of unculturable bacteria that were previously unknown. Most bacterial sequences identified in the canine gastrointestinal (GI) tract fall into five phyla: Firmicutes, Fusobacteria, Bacteroidetes, Proteobacteria, and Actinobacteria. While there are variations in the microbiome composition along the GI tract, most clinical studies concentrate on fecal microbiota. Age, diet, and many other environmental factors may play a significant role in the maintenance of a healthy microbiome, however, the alterations they cause pale in comparison with the alterations found in diseased animals. GI dysfunctions are the most obvious association with gut dysbiosis. In dogs, intestinal inflammation, whether chronic or acute, is associated with significant differences in the composition of the intestinal microbiota. Gut dysbiosis happens when such alterations result in functional changes in the microbial transcriptome, proteome, or metabolome. Commonly affected metabolites include short-chain fatty acids, and amino acids, including tryptophan and its catabolites. A recently developed PCR-based algorithm termed “Dysbiosis Index” is a tool that allows veterinarians to quantify gut dysbiosis and can be used to monitor disease progression and response to treatment. Alterations or imbalances in the microbiota affect immune function, and strategies to manipulate the gut microbiome may be useful for GI related diseases. Antibiotic usage induces a rapid and significant drop in taxonomic richness, diversity, and evenness. For that reason, a renewed interest has been put on probiotics, prebiotics, and fecal microbiota transplantation (FMT). Although probiotics are typically unable to colonize the gut, the metabolites they produce during their transit through the GI tract can ameliorate clinical signs and modify microbiome composition. Another interesting development is FMT, which may be a promising tool to aid recovery from dysbiosis, but further studies are needed to evaluate its potential and limitations.

Metagenomic analysis revealed beneficial effects of probiotics in improving the composition and function of the gut microbiota in dogs with diarrhoea

The aim of the present study was to evaluate the effects of probiotics on the composition and function of the gut microbiota in dogs with diarrhoea. Forty dogs with diarrhoea were randomly allocated to the treatment group or control group. Probiotics, containing Lactobacillus casei Zhang, Lactobacillus plantarum P-8, and Bifidobacterium animalis subsp. lactis V9, were only fed to 20 treated dogs for 60 days. The faecal samples of all dogs at day 0 and day 60 were analyzed using a metagenomic approach. The results showed a significantly higher microbial diversity and an obvious change in the structure of the gut microbiota in the treatment group. There was also an increase in the abundance of some beneficial bacteria in differently aged dogs, such as Lactobacillus johnsonii (P < 0.05), Lactobacillus reuteri (P < 0.01), Lactobacillus acidophilus (P < 0.05) and Butyricicoccus pullicaecorum (P < 0.05), and a reduction in the abundance of many opportunistic pathogenic bacteria such as Clostridium perfringens (P < 0.05) and Stenotrophomonas maltophilia (P < 0.05) with the supplementation of probiotics. Intriguingly, the correlated networks among some pathogenic bacteria decreased following the administration of probiotics. Additionally, metagenomic analysis revealed the upregulation of pathways involved in the metabolism of amino acids and biosynthesis of secondary metabolites, accompanied by the downregulation of pathways associated with virulence of pathogenic bacteria and cell signaling, suggesting that probiotics could improve the health of dogs with diarrhoea through regulation of the gut microbiota. Our research provides new information relevant to the treatment of diarrhoea in animals and humans.

Pharmaceutical Prescription in Canine Acute Diarrhoea: A Longitudinal Electronic Health Record Analysis of First Opinion Veterinary Practices

Canine acute diarrhoea is frequently observed in first opinion practice, though little is known about commonly used diagnostic or therapeutic management plans, including use of antimicrobials. This retrospective observational study utilised electronic health records augmented with practitioner-completed questionnaires from 3,189 cases (3,159 dogs) collected from 179 volunteer veterinary practices between April 2014 and January 2017. We used multivariable analysis to explore factors potentially associated with pharmaceutical agent prescription, and resolution of clinical signs by 10 days post-initial presentation. Use of bacteriological and/or parasitological diagnostic tests were uncommon (3.2% of cases, 95% confidence interval, CI, 2.4–4.0), though systemic antimicrobials were the most commonly prescribed pharmaceutical agents (49.7% of cases, 95% CI 46.1–53.2). Such prescription was associated with haemorrhagic diarrhoea (odds ratio, OR, 4.1; 95% CI 3.4–5.0), body temperature in excess of 39.0°C, or moderate/severe cases (OR 1.3, 95% CI 1.1–1.7). Gastrointestinal agents (e.g., antacids) were prescribed to 37.7% of cases (95% CI 35.4–39.9), and were most frequently prescribed to vomiting dogs regardless of presence (OR 46.4, 95% CI 19.4–110.8) or absence of blood (OR 17.1, 95% CI 13.4–21.9). Endoparasiticides/endectocides were prescribed to 7.8% of cases (95% CI 6.8–9.0), such prescription being less frequent for moderate/severe cases (OR 0.5, 95% CI 0.4–0.7), though more frequent when weight loss was recorded (OR 3.4, 95% CI 1.3–9.0). Gastrointestinal nutraceuticals (e.g., probiotics) were dispensed to 60.8% of cases (95% CI 57.1–64.6), these cases less frequently presenting with moderate/severe clinical signs (OR 0.6, 95% CI 0.5–0.8). Nearly a quarter of cases were judged lost to follow-up (n=754). Insured (OR 0.7, 95% CI 0.5–0.9); neutered (OR 0.4, 95% CI 0.3–0.5), or vaccinated dogs (OR 0.3, 95% CI 0.3–0.4) were less commonly lost to follow-up. Of remaining dogs, clinical signs were deemed resolved in 95.4% of cases (95% CI 94.6–96.2). Provision of dietary modification advice and gastrointestinal nutraceuticals alone were positively associated with resolution (OR 2.8, 95% CI 1.3–6.1); no such associations were found for pharmaceutical agents, including antimicrobials. Hence, this study supports the view that antimicrobials are largely unnecessary for acute diarrhoea cases; this being of particular importance when considering the global threat posed by antimicrobial resistance.

Prevalence of Clostridium perfringens netE and netF toxin genes in the feces of dogs with acute hemorrhagic diarrhea syndrome

BACKGROUND

Recently, novel pore-forming toxin genes designated netE and netF were identified in a Clostridium perfringens type A strain isolated from a dog with acute hemorrhagic diarrhea.

OBJECTIVES

Pore-forming toxins could play an important role in the disease pattern of acute hemorrhagic diarrhea syndrome (AHDS) in dogs. Thus, we aimed to determine the prevalence of C. perfringens genes encoding for netE and netF in the feces of dogs with AHDS and to evaluate any association between selected clinical variables and the presence of these toxin genes.

ANIMALS

In total, 174 dogs were included in the study.

METHODS

Fecal samples of all dogs were tested by real-time polymerase chain reaction for netE and netF genes. Time to recovery, hospitalization time, and selected laboratory variables were compared between dogs with AHDS that were positive or negative for the toxin genes.

RESULTS

A significant difference was found among the 3 groups in the prevalence of the pore-forming toxin genes netE and netF: dogs with AHDS: 26 of 54 (48.1%); dogs with canine parvovirus (CPV) infection: 0 of 54 (0%); and healthy dogs: 8 of 66 (12.1%; P < .001). In dogs with AHDS, no significant difference was detected in any variables evaluated between netE-positive and netF-positive and netE-negative and netF-negative dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

The prevalence of C. perfringens encoding for netE and netF is significantly higher in dogs with AHDS compared to control dogs. Further studies are warranted to evaluate whether these toxins are an inciting cause for AHDS in dogs.

Effect of probiotic treatment on the clinical course, intestinal microbiome, and toxigenic Clostridium perfringens in dogs with acute hemorrhagic diarrhea

INTRODUCTION

The impact of probiotics on dogs with acute hemorrhagic diarrhea syndrome (AHDS) has not been evaluated so far. The study aim was to assess the effect of probiotic treatment on the clinical course, intestinal microbiome, and toxigenic Clostridium perfringens in dogs with AHDS in a prospective, placebo-controlled, blinded trial.

METHODS

Twenty-five dogs with AHDS with no signs of sepsis were randomly divided into a probiotic (PRO; Visbiome, ExeGi Pharma) and placebo group (PLAC). Treatment was administered for 21 days without antibiotics. Clinical signs were evaluated daily from day 0 to day 8. Key bacterial taxa, C. perfringens encoding NetF toxin and enterotoxin were assessed on days 0, 7, 21.

RESULTS

Both groups showed a rapid clinical improvement. In PRO a significant clinical recovery was observed on day 3 (p = 0.008), while in PLAC it was observed on day 4 (p = 0.002) compared to day 0. Abundance of Blautia (p<0.001) and Faecalibacterium (p = 0.035) was significantly higher in PRO on day 7 compared to day 0, while in PLAC the abundance of Faecalibacterium was not significantly higher on any study day and Blautia (p = 0.016) was only significantly higher on day 21 compared to day 0. Abundance of C. perfringens was significantly lower on day 7 (p = 0.011) compared to day 0 in PRO but not in PLAC. Enterotoxin genes were significantly lower in PRO on day 21 (p = 0.028) compared to PLAC. Fecal samples of 57% of all dogs were positive for netF toxin genes on day 0 and the abundance was significantly lower on day 7 compared to day 0 in PRO (p = 0.016) and PLAC (p = 0.031).

CONCLUSION

The probiotic treatment was associated with an accelerated normalization of the intestinal microbiome. Dogs with aseptic AHDS showed a rapid decrease of netF toxin genes and fast clinical recovery in both groups under symptomatic treatment without antibiotics.

Acute hemorrhagic diarrhea syndrome associated with contaminated foreign bodies (used feminine hygiene products) in a Golden Retriever dog

A one-year-old male Golden Retriever presented with acute onset of vomiting and hemorrhagic diarrhea since 2 days. The dog was depressed, showing abdominal pain, 12% dehydration, tachycardia, and a bounding pulse. Diagnostic imaging showed severe dilatation and fluid retention of the entire gastrointestinal tract with decreased motility. A foreign body was found in the gastroduodenal region, but there was no obstruction or plication. The dog was tentatively diagnosed with acute hemorrhagic diarrhea syndrome and rapidly recovered after supportive treatment. However, on the morning of day 4, anorexia and vomiting recurred, and diagnostic imaging revealed intestinal plication with free peritoneal fluid, not found on the previous image. An emergency laparotomy revealed the foreign body to be two used feminine hygiene products. These contaminated products were suspected to induce acute hemorrhagic diarrhea syndrome, and led to subsequent complication in this large dog.

Intestinal lesions in dogs with acute hemorrhagic diarrhea syndrome associated with netF-positive Clostridium perfringens type A

Acute hemorrhagic diarrhea syndrome (AHDS), formerly named canine hemorrhagic gastroenteritis, is one of the most common causes of acute hemorrhagic diarrhea in dogs, and is characterized by acute onset of diarrhea, vomiting, and hemoconcentration. To date, histologic examinations have been limited to postmortem specimens of only a few dogs with AHDS. Thus, the aim of our study was to describe in detail the distribution, character, and grade of microscopic lesions, and to investigate the etiology of AHDS. Our study comprised 10 dogs with AHDS and 9 control dogs of various breeds, age, and sex. Endoscopic biopsies of the gastrointestinal tract were taken and examined histologically (H&E, Giemsa), immunohistochemically ( Clostridium spp., parvovirus), and bacteriologically. The main findings were acute necrotizing and neutrophilic enterocolitis (9 of 10) with histologic detection of clostridia-like, gram-positive bacteria on the necrotic mucosal surface (9 of 10). Clostridium perfringens isolated from the duodenum was identified as type A (5 of 5) by multiplex PCR (5 of 5). In addition, each of the 5 genotyped isolates encoded the pore-forming toxin netF. Clostridium spp. (not C. perfringens) were cultured from duodenal biopsies in 2 of 9 control dogs. These findings suggest that the pore-forming netF toxin is responsible for the necrotizing lesions in the intestines of a significant proportion of dogs with AHDS. Given that the stomach was not involved in the process, the term "acute hemorrhagic diarrhea syndrome" seems more appropriate than the frequently used term "hemorrhagic gastroenteritis."

NetF-producing Clostridium perfringens: Clonality and plasmid pathogenicity loci analysis

Clostridium perfringens is an important cause of foal necrotizing enteritis and canine acute hemorrhagic diarrhea. A major virulence determinant of the strains associated with these diseases appears to be a beta-sheet pore-forming toxin, NetF, encoded within a pathogenicity locus (NetF locus) on a large tcp-conjugative plasmid. Strains producing NetF also produce the putative toxin NetE, encoded within the same pathogenicity locus, as well as CPE enterotoxin and CPB2 on a second plasmid, and sometimes the putative toxin NetG within a pathogenicity locus (NetG locus) on another separate large conjugative plasmid. Previous genome sequences of two netF-positive C. perfringens showed that they both shared three similar plasmids, including the NetF/NetE and CPE/CPB2 toxins-encoding plasmids mentioned above and a putative bacteriocin-encoding plasmid. The main purpose of this study was to determine whether all NetF-producing strains share this common plasmid profile and whether their distinct NetF and CPE pathogenicity loci are conserved. To answer this question, 15 equine and 15 canine netF-positive isolates of C. perfringens were sequenced using Illumina Hiseq2000 technology. In addition, the clonal relationships among the NetF-producing strains were evaluated by core genome multilocus sequence typing (cgMLST). The data obtained showed that all NetF-producing strains have a common plasmid profile and that the defined pathogenicity loci on the plasmids are conserved in all these strains. cgMLST analysis showed that the NetF-producing C. perfringens strains belong to two distinct clonal complexes. The pNetG plasmid was absent from isolates of one of the clonal complexes, and there were minor but consistent differences in the NetF/NetE and CPE/CPB2 plasmids between the two clonal complexes.

Remodeling of the gut microbiota and structural shifts in Preeclampsia patients in South China

Preeclampsia (PE) is one of the pregnancy metabolic diseases. Since Gut microbiota play important roles in the hosts' metabolism, it is necessary to investigate the gut microbiota in PE patients, so that some intestinal dysbiosis might be detected as a biomarker for PE early diagnosis or as a target for intervention. One hundred subjects were categorized into four groups: 26 PE patients in late pregnancy, healthy individuals in early, middle, and late pregnancy (26/24/24 women). Gut microbiota were analyzed by sequencing the V4 region of the 16S rDNA gene using Illuminal MiSeq. Data were analyzed by multivariate statistics. Bacteroidetes was the dominant bacterium (47.57-52.35%) in the pregnant women in South China. Tenericutes increased while Verrucomicrobia almost disappeared in late pregnancy. In the PE patients, there was an overall increase in pathogenic bacteria, Clostridium perfringens (p = 0.03) and Bulleidia moorei (p = 0.00) but a reduction in probiotic bacteria Coprococcus catus (p = 0.03). Our research suggests that there is a significant structural shift of the gut microbiota in PE patients, which might be associated with the occurrence and development of the disease. However, further studies are required to understand the underlying mechanisms.

Understanding the canine intestinal microbiota and its modification by pro-, pre- and synbiotics - what is the evidence?

Interest in the composition of the intestinal microbiota and possibilities of its therapeutic modifications has soared over the last decade and more detailed knowledge specific to the canine microbiota at different mucosal sites including the gut is available. Probiotics, prebiotics or their combination (synbiotics) are a way of modifying the intestinal microbiota and exert effects on the host immune response. Probiotics are proposed to exert their beneficial effects through various pathways, for example production of antimicrobial peptides, enhancing growth of favourable endogenous microorganisms, competition for epithelial colonisation sites and immune‐modulatory functions. Despite widespread use of pro‐, pre‐ and synbiotics, scientific evidence of their beneficial effects in different conditions of the dog is scarce. Specific effects of different strains, their combination or their potential side‐effects have not been evaluated sufficiently. In some instances, in vitro results have been promising, but could not be transferred consistently into in vivo situations. Specific canine gastrointestinal (GI) diseases or conditions where probiotics would be beneficial, their most appropriate dosage and application have not been assessed extensively. This review summarises the current knowledge of the intestinal microbiome composition in the dog and evaluates the evidence for probiotic use in canine GI diseases to date. It wishes to provide veterinarians with evidence‐based information on when and why these products could be useful in preventing or treating canine GI conditions. It also outlines knowledge about safety and approval of commercial probiotic products, and the potential use of faecal microbial transplantation, as they are related to the topic of probiotic usage.

A novel pore-forming toxin in type A Clostridium perfringens is associated with both fatal canine hemorrhagic gastroenteritis and fatal foal necrotizing enterocolitis

A role for type A Clostridium perfringens in acute hemorrhagic and necrotizing gastroenteritis in dogs and in necrotizing enterocolitis of neonatal foals has long been suspected but incompletely characterized. The supernatants of an isolate made from a dog and from a foal that died from these diseases were both found to be highly cytotoxic for an equine ovarian (EO) cell line. Partial genome sequencing of the canine isolate revealed three novel putative toxin genes encoding proteins related to the pore-forming Leukocidin/Hemolysin Superfamily; these were designated netE, netF, and netG. netE and netF were located on one large conjugative plasmid, and netG was located with a cpe enterotoxin gene on a second large conjugative plasmid. Mutation and complementation showed that only netF was associated with the cytotoxicity. Although netE and netG were not associated with cytotoxicity, immunoblotting with specific antisera showed these proteins to be expressed in vitro. There was a highly significant association between the presence of netF with type A strains isolated from cases of canine acute hemorrhagic gastroenteritis and foal necrotizing enterocolitis. netE and netF were found in all cytotoxic isolates, as was cpe, but netG was less consistently present. Pulsed-field gel electrophoresis showed that netF-positive isolates belonged to a clonal population; some canine and equine netF-positive isolates were genetically indistinguishable. Equine antisera to recombinant Net proteins showed that only antiserum to rNetF had high supernatant cytotoxin neutralizing activity. The identifica-tion of this novel necrotizing toxin is an important advance in understanding the virulence of type A C. perfringens in specific enteric disease of animals.

Prospective study of bacteraemia in acute haemorrhagic diarrhoea syndrome in dogs

In dogs with idiopathic acute haemorrhagic diarrhoea syndrome (AHDS), a serious loss of intestinal mucosal barrier integrity occurs. However, the incidence of bacterial translocation in dogs with idiopathic AHDS is not known. Thus, the objectives of this prospective study were to identify the incidence of bacteraemia, to evaluate the frequency of septic events and the influence of bacteraemia on various clinical and laboratory parameters, duration of hospitalisation and survival of dogs with idiopathic AHDS. The study included 87 dogs with idiopathic AHDS. Twenty-one healthy dogs served as control group. To evaluate clinical significance of bacterial translocation, blood culture results were compared between patients and controls. Clinical and laboratory parameters were compared between patients with positive and negative blood cultures. There was no significant difference in either incidence of bacteraemia between patients with idiopathic AHDS (11 per cent) and controls (14 per cent) or in severity of clinical signs, laboratory parameters, duration of hospitalisation or mortality between blood culture-positive and culture-negative dogs with idiopathic AHDS. The results of this study suggest that the incidence of bacteraemia in dogs with idiopathic AHDS is low and not different from that of healthy control dogs. Bacteraemia does not influence the clinical course or survival and thus antibiotic treatment is not indicated to prevent sepsis.

Prevalence of Clostridium perfringens, Clostridium perfringens enterotoxin and dysbiosis in fecal samples of dogs with diarrhea

Clostridium perfringens has been suspected as an enteropathogen in dogs. However, its exact role in gastrointestinal (GI) disorders in dogs remains unknown. Recent studies suggest the importance of an altered intestinal microbiota in the activation of virulence factors of enteropathogens. The aim of this study was to evaluate the relationship between diarrhea, dysbiosis, and the presence of C. perfringens and its enterotoxin (CPE). Fecal samples were collected prospectively from 95 healthy control dogs and 104 dogs with GI disease and assessed for bacterial abundances and the presence of CPE using quantitative PCR and ELISA, respectively. C. perfringens was detected in all dogs. Potentially enterotoxigenic C. perfringens were detected in 33.7% (32/95) of healthy control dogs and 48.1% (50/104) diseased dogs, respectively. CPE was detected by ELISA in 1.0% (1/95) of control dogs and 16.3% (17/104) of diseased dogs. Abundances of Fusobacteria, Ruminococcaceae, Blautia, and Faecalibacterium were significantly decreased in diseased dogs, while abundances of Bifidobacterium, Lactobacillus, and Escherichia coli were significantly increased compared to control dogs. The microbial dysbiosis was independent of the presence of the enterotoxigenic C. perfringens or CPE. In conclusion, the presence of CPE as well as fecal dysbiosis was associated with GI disease. However, the presence of C. perfringens was not indicative of GI disease in all cases of diarrhea, and the observed increased abundance of enterotoxigenic C. perfringens may be part of intestinal dysbiosis occurring in GI disease. The significance of an intestinal dysbiosis in dogs with GI disease deserves further attention.