Chronic Diarrhea in Dogs: What Do We Actually Know About It?

There is a paucity of research based knowledge about chronic diarrhoea in dogs. In the literature no studies can be found that confirms that round worm, whip worm, hook worm or giardia cause chronic diarrhoea in dogs. For this reason, it is questionable to study endoparasites when clarifying the reason for chronic diarrhoea in dogs. No study confirms that clostridium-, campylobacter- or salmonella species cause chronic diarrhoea signs in dogs. There is no research-based information to-date that endoscopy would be helpful in the diagnosis of dogs with chronic diarrhoea or to monitor how the disease progresses. Neither no reliable laboratory test can be recommended to be used in evaluating the seriousness of the disease or to monitor the progress of the disease. There is no evidence based information on what food should be recommended for dogs suffering from diarrhoea. Only a few studies have been published that show how effective antibiotics are in the treatment of diarrhoeal dogs. Many more studies are needed before it is possible to determine how effective corticosteroids are in the treatment of diarrhoea in dogs.

The effects of feeding and withholding food on the canine small intestinal microbiota.

Prolonged lack of enteral feeding has a negative impact on gut physiology, potentially via microbiota modulation. The aims were to investigate the impact of fasting and post-prandial changes in canine jejunal microbiota. To study post-prandial effects, jejunal brushings were analyzed in 8 healthy fistulated dogs 15 min before feeding (baseline) and hourly for 8 h after feeding. To study effects of withholding food (WF), daily samples were collected for 15 days from 5 dogs. The first 5 days (PRE) dogs were fed regular diet. Food was withheld the next 5 days (days 6-10). For days 11-15 (POST), the original diet was reintroduced. Microbiota was characterized via denaturing gradient gel electrophoresis and 454-pyrosequencing of 16S rRNA genes. In the post-prandial study, no changes in microbiome structure were seen after feeding (ANOSIM, P = 0.28), but Betaproteobacteria (P = 0.04) and Bacteroidales decreased compared to baseline. Species richness decreased by 300 min (P = 0.04). During WF, microbiota structure differed from PRE and POST period (P = 0.001). During WF, species richness did not vary over time (P = 0.69). In conclusion, a prolonged period of food withholding results in altered jejunal microbiota. How these changes affect the microbiota metabolism warrants further studies.

Oral tylosin administration is associated with an increase of faecal enterococci and lactic acid bacteria in dogs with tylosin-responsive diarrhoea.

The term tylosin-responsive diarrhoea (TRD) is used for canine recurrent diarrhoea cases for which no underlying cause can be found after extensive diagnostic investigations, but which show a response to the antibiotic tylosin in a few days. The objective of this prospective, one-arm longitudinal trial was to assess the effects of oral tylosin administration on the faecal levels of potentially probiotic bacteria, such as Enterococcus spp. and lactic acid bacteria (LAB), in dogs with TRD. This trial included 14 client-owned suspected TRD dogs that were on tylosin treatment and had firm faeces. Treatment was then terminated and dogs were followed up for up to 2 months to determine the recurrence of diarrhoea. Once diarrhoea started, dogs received tylosin (orally, 25 mg/kg, once daily for 7 days). At the end of the treatment period, stools were firm again in 11 dogs (TRD dogs); three dogs continued having diarrhoea and were excluded from the study. Faecal samples were collected at all three time-points for culture of LAB and enterococci. In TRD dogs, the colony counts of Enterococcus spp. (P = 0.003), LAB (P = 0.037), tylosin-resistant Enterococcus spp. (P <0.001) and LAB (P <0.001) were significantly higher when the dogs were on tylosin treatment and had normal faecal consistency compared to when they had diarrhoea following discontinuation of tylosin. In conclusion, cessation of diarrhoea in TRD dogs with tylosin treatment could be mediated by selection of a specific lactic acid population, the Enterococcus spp., due to their potential probiotic properties.

Efficacy of two low-dose oral tylosin regimens in controlling the relapse of diarrhea in dogs with tylosin-responsive diarrhea: a prospective, single-blinded, two-arm parallel, clinical field trial.

BACKGROUND: Despite its wide acceptance as a treatment for canine chronic enteropathies, the macrolide antibiotic tylosin lacks official oral dosage recommendations. Not even textbooks share consensus about the dose; daily recommendations vary from 25 to 80 mg/kg and dosing intervals from one to three times daily. RESULTS: All eight dogs responded to the 5 mg/kg dose, and six of seven dogs responded to the 15 mg/kg dose. The mean fecal consistency scores at the 25 mg/kg tylosin dosage were no significantly different from scores at the 5 mg/kg or 15 mg/kg tylosin dosages (P=0.672, P=0.345). CONCLUSIONS: Interestingly, 14/15 (93%) of the dogs responding to a dose of 25 mg/kg tylosin once daily for seven days also responded to the lower dosages at diarrhea relapse. The data indicate that a suitable dose of tylosin for treating diarrhea relapse in canine TRD could be as low as 5 mg/kg once daily for seven days.

Exocrine pancreatic insufficiency in the dog: historical background, diagnosis, and treatment.

This overview summarizes research performed during the last decades that has had an impact on the diagnosis and management of exocrine pancreatic insufficiency (EPI) in dogs. Pancreatic acinar atrophy is by far the most common cause for the maldigestion signs of canine EPI. The ability to diagnose pancreatic acinar atrophy in the subclinical phase before the development of total acinar atrophy and manifestation of clinical signs has offered new possibilities to study the pathogenesis of the disease. Diagnosis of exocrine pancreatic dysfunction is based on typical findings in clinical histories and clinical signs and is confirmed with pancreatic function tests. In recent years, the measurement of serum canine trypsin-like immunoreactivity has become the most commonly used pancreatic function test to diagnose canine EPI. Serum trypsin-like immunoreactivity measurement is species- and pancreas-specific. When clinical maldigestion signs of EPI appear, enzyme replacement therapy is indicated. Despite accurate enzyme supplementation, only a small portion of orally administered enzymes are delivered functionally intact into the small intestine. In dogs, the highest enzyme activity in the duodenum has been obtained with nonenteric-coated supplements: raw chopped pancreas or powdered enzymes. Aside from dietary enzyme supplements, dietary changes are often made to improve clinical response, but sometimes weight gain and stool quality remain suboptimal. Other medications for treatment of gastrointestinal tract signs are often used in such dogs with EPI. Antibiotics are the most common adjunctive medication. Of the antibiotics administered, tylosin is used in Finland almost exclusively.

Urinary recovery of orally administered chromium 51-labeled EDTA, lactulose, rhamnose, d-xylose, 3-O-methyl-d-glucose, and sucrose in healthy adult male Beagles.

Objective-To provide values for gastrointestinal permeability and absorptive function tests (GIPFTs) with chromium 51 ((51)Cr)-labeled EDTA, lactulose, rhamnose, d-xylose, 3-O-methyl-d-glucose, and sucrose in Beagles and to evaluate potential correlations between markers. Animals-19 healthy adult male Beagles. Procedures-A test solution containing 3.7 MBq of (51)Cr-labeled EDTA, 2 g of lactulose, 2 g of rhamnose, 2 g of d-xylose, 1 g of 3-O-methyl-d-glucose, and 8 g of sucrose was administered intragastrically to each dog. Urinary recovery of each probe was determined 6 hours after administration. Results-Mean ± SD (range) percentage urinary recovery was 6.3 ± 1.6% (4.3% to 9.7%) for (51)Cr-labeled EDTA, 3.3 ± 1.1% (1.7% to 5.3%) for lactulose, 25.5 ± 5.0% (16.7% to 36.9%) for rhamnose, and 58.8% ± 11.0% (40.1% to 87.8%) for 3-O-methyl-d-glucose. Mean (range) recovery ratio was 0.25 ± 0.06 (0.17 to 0.37) for (51)Cr-labeled EDTA to rhamnose, 0.13 ± 0.04 (0.08 to 0.23) for lactulose to rhamnose, and 0.73 ± 0.09 (0.60 to 0.90) for d-xylose to 3-O-methyl-d-glucose. Median (range) percentage urinary recovery was 40.3% (31.6% to 62.7%) for d-xylose and 0% (0% to 0.8%) for sucrose. Conclusions and Clinical Relevance-Reference values in healthy adult male Beagles for 6 of the most commonly used GIPFT markers were determined. The correlation between results for (51)Cr-labeled EDTA and lactulose was not as prominent as that reported for humans and cats; thus, investigators should be cautious in the use and interpretation of GIPFTs performed with sugar probes in dogs with suspected intestinal dysbiosis.

Comparison of 51chromium-labeled ethylenediamine tetra-acetic acid and iohexol as blood markers for intestinal permeability testing in Beagle dogs.

(51)Chromium-labeled ethylenediamine tetra-acetic acid ((51)Cr-EDTA) is the gold standard probe for assessing intestinal permeability (IP) in dogs, but exposure to radioactivity is a disadvantage. Iohexol is a safe contrast medium commonly used for medical imaging purposes and has been successfully applied more recently for the assessment of IP in animal models and humans. This study aimed at comparing (51)Cr-EDTA and iohexol as IP blood markers in dogs. A test solution containing (51)Cr-EDTA and iohexol was administered intragastrically to seven healthy laboratory Beagle dogs, and percentage recoveries in serum were calculated. The strong linear association (correlation, r=0.76 and linear regression, y=0.03+5.04x) between (51)Cr-EDTA and iohexol supports the potential usefulness of iohexol as an IP blood marker in dogs.

Effect of tylosin on dogs with suspected tylosin-responsive diarrhea: a placebo-controlled, randomized, double-blinded, prospective clinical trial.

BACKGROUND: The macrolid antibiotic tylosin has been widely used to treat canine chronic diarrhea, although its efficacy is based on anecdotal reports and experimental studies in dogs and not on strong scientific evidence. The term tylosin-responsive diarrhea (TRD) refers to diarrheal disorders responding to tylosin therapy within a few days. In TRD, the stool remains normal as long as tylosin treatment continues, but diarrhea reappears in many dogs within weeks after discontinuation. The aim of our trial was to assess the effect of tylosin on fecal consistency compared with a placebo treatment in dogs with suspected TRD and additionally to establish whether tylosin in dogs with recurrent diarrhea is as effective as empirical studies and anecdotal reports suggest. METHODS: Subjects comprised 71 client-owned dogs that, according to the owners, had previously been treated successfully with tylosin due to recurrent diarrhea of unknown etiology. At the initial examination, where there were no signs of diarrhea, the dogs were randomly assigned in a 2:1 ratio to a tylosin or placebo group. During a two-month follow-up the owners evaluated the fecal consistency according to previously published guidelines. When diarrhea recurred, either tylosin (25 mg/kg q 24 h, 7 days) or placebo treatment was initiated orally. Treatment outcome was evaluated as the mean of fecal consistency scores assigned during the last three days of the treatment period. To test for differences between the tylosin and placebo group in the proportion of responders, Pearson's Chi-squared test and Fisher's exact test were applied. RESULTS: Sixty-one dogs met the selection criteria and were followed for two months. During the follow-up 27 dogs developed diarrhea and either tylosin or placebo treatment was started. The proportion of dogs with normal fecal consistency at the end of treatment was 85% (17/20) in the tylosin group and 29% (2/7) in the placebo group (Pearson's Chi-squared test p = 0.0049 and Fisher's exact test two-sided, p = 0.0114). CONCLUSIONS: Our findings indicate that tylosin is effective in treating recurrent diarrhea in dogs. The dose of 25 mg/kg once daily appears sufficient. No changes specific to TRD were detected in the examinations.

The 51-chromium-labeled ethylenediamine tetra-acetic acid intestinal permeability blood test in healthy Beagle dogs: a comparison between serum and plasma levels.

A 51-chromium-labeled ethylenediamine tetra-acetic acid ((51)Cr-EDTA) permeability blood test was validated as a method to assess damage to the small intestine in dogs. The test was performed by calculating various percentages from sera after an orally ingested dose solution. The aim of the current study was to determine whether the use of serum or plasma had any influence on the results of the test. A test solution with 3.7 megabecquerel (100 µCi) of (51)Cr-EDTA was delivered through an orogastric tube to 13 healthy laboratory Beagle dogs. From each dog, 2 concurrent blood samples were withdrawn from cephalic veins using clotting-factor activator tubes for serum and heparinized tubes for plasma. The samples (n  =  26) were taken at 3 and 5 hr after administration of the test solution. Percentages of the orally ingested dose were then calculated in serum and plasma, and their relationship was assessed using correlation analysis. The mean ± standard deviation percentages in serum and plasma after 3 hr were 0.85 ± 0.43% and 0.88 ± 0.49%, respectively, whereas respective percentages in serum and plasma after 5 hr were 0.78 ± 0.52% and 0.81 ± 0.51%. The combined correlation coefficient between the percentages from the sera and plasma samples was excellent (R  =  0.98). It was concluded that the (51)Cr-EDTA permeability test in blood may be performed using serum or plasma of dogs, and the choice between the 2 samples is one of convenience.

Small intestinal permeability and serum folate and cobalamin absorption after surgical construction of permanent jejunal fistulas in laboratory beagle dogs.

Permanent jejunal fistulas enable easy, noninjurious, repeated and direct administration to and collection from the small intestines of conscious laboratory dogs. This study aimed at identifying potential alterations in the small intestinal morphology and function of this canine model after the surgery required to establish the fistulas. Assays of serum folate and cobalamin and (51)Cr-EDTA permeability tests were performed before and 4 wk after experimental jejunoplasties in 14 laboratory beagle dogs. Serum folate concentrations (mean ± SD) before (12.22 ± 1.80 µg/L) and after (14.14 ± 1.70 µg/L) jejunal surgery were within reference ranges for healthy dogs, although folate concentrations were higher after surgery. The cobalamin concentrations and the 6-h urinary excretion of (51)Cr-EDTA before (573.50 ± 150.04 ng/L and 6.75 ± 1.56%, respectively) and after (496.71 ± 164.22 ng/L and 6.41 ± 1.10%) were normal for healthy dogs, and no significant differences between pre- and postsurgical values were detected. The findings of the present study indicate that the small intestinal vitamin absorption and permeability of laboratory beagle dogs with jejunal fistulas remains unimpaired.

The effect of the macrolide antibiotic tylosin on microbial diversity in the canine small intestine as demonstrated by massive parallel 16S rRNA gene sequencing.

BACKGROUND: Recent studies have shown that the fecal microbiota is generally resilient to short-term antibiotic administration, but some bacterial taxa may remain depressed for several months. Limited information is available about the effect of antimicrobials on small intestinal microbiota, an important contributor to gastrointestinal health. The antibiotic tylosin is often successfully used for the treatment of chronic diarrhea in dogs, but its exact mode of action and its effect on the intestinal microbiota remain unknown. The aim of this study was to evaluate the effect of tylosin on canine jejunal microbiota. Tylosin was administered at 20 to 22 mg/kg q 24 hr for 14 days to five healthy dogs, each with a pre-existing jejunal fistula. Jejunal brush samples were collected through the fistula on days 0, 14, and 28 (14 days after withdrawal of tylosin). Bacterial diversity was characterized using massive parallel 16S rRNA gene pyrosequencing. RESULTS: Pyrosequencing revealed a previously unrecognized species richness in the canine small intestine. Ten bacterial phyla were identified. Microbial populations were phylogenetically more similar during tylosin treatment. However, a remarkable inter-individual response was observed for specific taxa. Fusobacteria, Bacteroidales, and Moraxella tended to decrease. The proportions of Enterococcus-like organisms, Pasteurella spp., and Dietzia spp. increased significantly during tylosin administration (p < 0.05). The proportion of Escherichia coli-like organisms increased by day 28 (p = 0.04). These changes were not accompanied by any obvious clinical effects. On day 28, the phylogenetic composition of the microbiota was similar to day 0 in only 2 of 5 dogs. Bacterial diversity resembled the pre-treatment state in 3 of 5 dogs. Several bacterial taxa such as Spirochaetes, Streptomycetaceae, and Prevotellaceae failed to recover at day 28 (p < 0.05). Several bacterial groups considered to be sensitive to tylosin increased in their proportions. CONCLUSION: Tylosin may lead to prolonged effects on the composition and diversity of jejunal microbiota. However, these changes were not associated with any short-term clinical signs of gastrointestinal disease in healthy dogs. Our results illustrate the complexity of the intestinal microbiota and the challenges associated with evaluating the effect of antibiotic administration on the various bacterial groups and their potential interactions.

Prevalence and identification of fungal DNA in the small intestine of healthy dogs and dogs with chronic enteropathies.

Limited information is available about the prevalence and phylogenetic classification of fungal organisms in the gastrointestinal tract of dogs. Also, the impact of fungal organisms on gastrointestinal health and disease is not well understood. The aim of this study was to evaluate the prevalence of fungal DNA in the small intestine of healthy dogs and dogs with chronic enteropathies. Small intestinal content was analyzed from 64 healthy and 71 diseased dogs from five different geographic locations in Europe and the USA. Fungal DNA was amplified with panfungal primers targeting the internal transcriber spacer (ITS) region. PCR amplicons were subjected to phylogenetic analysis. Fungal DNA was detected in 60.9% of healthy dogs and in 76.1% of dogs with chronic enteropathies. This prevalence was not significantly different between the two groups (p=0.065). Fungal DNA was significantly more prevalent in mucosal brush samples (82.8%) than in luminal samples (42.9%; p=0.002). Sequencing results revealed a total of 51 different phylotypes. All sequences belonged to two phyla and were classified as either Ascomycota (32 phylotypes) or Basidiomycota (19 phylotypes). Three major classes were identified: Saccharomycetes, Dothideomycetes, and Hymenomycetes. The most commonly observed sequences were classified as Pichia spp., Cryptococcus spp., Candida spp., and Trichosporon spp. Species believed to be clinically more important were more commonly observed in diseased dogs. These results indicate a high prevalence and diversity of fungal DNA in the small intestine of both healthy dogs and dogs with chronic enteropathies. The canine gastrointestinal tract of diseased dogs may harbor opportunistic fungal pathogens.

Effects of diet on clinical signs of exocrine pancreatic insufficiency in dogs.

OBJECTIVE: To assess the effects of dietary modification on clinical signs of exocrine pancreatic insufficiency (EPI) in dogs. DESIGN: Blinded randomized crossover study. ANIMALS: 21 dogs with EPI. PROCEDURE: Dogs were fed the diet they received at home for 2 weeks. Thereafter, they received 3 special diets (a high-fat diet, a high-fiber diet, and a highly digestible low-residue diet) for 3 weeks each. Owners scored dogs daily for the last 2 weeks of each 3-week period for severity of 6 clinical signs including appetite, defecation frequency, consistency of feces, borborygmus, flatulence, and coprophagia. An EPI index was calculated for each dog by adding the daily scores for each clinical sign. RESULTS: Significant differences in daily EPI indices among diets were observed in 20 dogs. The original diet appeared to be the most suitable in 8 dogs, whereas the high-fat diet was most suitable in 5 dogs, the high-fiber diet was most suitable in 4 dogs, and the low-residue diet was most suitable in 2 dogs. In 1 dog, the lowest EPI index score was the same during the original diet and the high-fat diet feeding periods. One dog did not complete the feeding period for the high-fiber diet. Differences in mean EPI indices among diets were not significant. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that responses to different diets varied among individual dogs. Because responses to the feeding regimens were unpredictable, it is suggested that feeding regimens be individually formulated for dogs with EPI.

Relatedness of Escherichia coli strains with different susceptibility patterns isolated from beagle dogs during ampicillin treatment.

The aim of this study was to investigate the effects of ampicillin treatment on selection and diversity of ampicillin-resistant intestinal Escherichia coli in beagles treated with ampicillin, ampicillin + beta-lactamase (targeted to degrade antibiotic residues in the gut) or placebo. Selected faecal (n = 339) and jejunal (n = 63) E. coli isolates with known resistance patterns were typed using pulsed-field gel electrophoresis (PFGE). Among the 25 detected PFGE types, ampicillin resistance was detected in 6, none of which was dominant over others among the dogs. The resistant types increased especially in the ampicillin group, whilst beta-lactamase inhibited their emergence. Selection of genetically unrelated resistant strains rather than emerging resistance among previously susceptible strains accounts for increasing resistance rates during ampicillin treatment.

Effect of diet and tylosin on chronic diarrhea in beagles.

Seven beagles in a colony of dogs had chronic diarrhea for at least 30 days. The dogs were subsequently treated with tylosin 20 mg/kg BW q24h PO for 10 days. During the treatment period, the feces became firmer but remained loose. When the treatment was discontinued, the diarrhea reappeared in 3 weeks. The feces remained abnormally loose in all dogs treated with metronidazole, trimethoprim-sulfadiazine, or doxycycline and prednisone. The diet was then changed for 10 days from a highly digestible moist pet food to a dry food developed for normal adult dogs. The feces again became firmer, although still loose in some dogs. The period was then extended to 3 month, but the fecal consistency continued to fluctuate from ideal to diarrhea. The dogs were treated a 2nd time with tylosin 20 mg/kg BW q24h PO for 10 days. The feces then became significantly firmer and remained so throughout a 3-month follow-up. We conclude that the combination of diet and tylosin was more effective than either agent alone in control of chronic diarrhea.

Comparison between cultured small-intestinal and fecal microbiotas in beagle dogs.

The microbiota of the small intestine is poorly known because of difficulties in sampling. In this study, we examined whether the organisms cultured from the jejunum and feces resemble each other. Small-intestinal fluid samples were collected from 22 beagle dogs with a permanent jejunal fistula in parallel with fecal samples. In addition, corresponding samples from seven of the dogs were collected during a 4-week period (days 4, 10, 14, and 28) to examine the stability of the microbiota. In the jejunal samples, aerobic/facultative and anaerobic bacteria were equally represented, whereas anaerobes dominated in the fecal samples. Despite lower numbers of bacteria in the jejunum (range, 10(2) to 10(6) CFU/g) than in feces (range, 10(8) to 10(11) CFU/g), some microbial groups were more prevalent in the small intestine: staphylococci, 64% versus 36%; nonfermentative gram-negative rods, 27% versus 9%; and yeasts, 27% versus 5%, respectively. In contrast, part of the fecal dominant microbiota (bile-resistant Bacteroides spp., Clostridium hiranonis-like organisms, and lactobacilli) was practically absent in the jejunum. Many species were seldom isolated simultaneously from both sample types, regardless of their overall prevalence. In conclusion, the small intestine contains a few bacterial species at a time with vastly fluctuating counts, opposite to the results obtained for the colon, where the major bacterial groups remain relatively constant over time. Qualitative and quantitative differences between the corresponding jejunal and fecal samples indicate the inability of fecal samples to represent the microbiotas present in the upper gut.

Endoscopic retrograde cholangio-pancreatography in healthy Beagles.

Endoscopic retrograde cholangiography and pancreatography was performed in seven healthy Beagles to assess the common bile duct and the accessory pancreatic duct after retrograde filling with an iodine contrast medium. All dogs had a major and a minor duodenal papilla. One Beagle had additionally an accessory papilla. The diameter of the contrast filled ducts was measured at three defined measure points (MP1-3) in ventrodorsal radiographs and left lateral radiographs. In ventrodorsal radiographs of endoscopic retrograde cholangiography the common bile duct had a straight craniomedial course. The mean duct diameter was from proximal to distal 3.04 +/- 1.89mm at MP1, 2.38 +/- 1.23 mm at MP2, and 2.11 +/- 0.84 mm at MP3. In ventrodorsal radiographs of endoscopic retrograde pancreatography, the left and right branch of the accessory pancreatic duct united in the pancreatic body. The mean diameter of the right branch was 0.88 +/- 0.14 mm at MP1, 0.72 +/- 0.2 mm at MP2 and 0.61 +/- 0.11 mm at MP3. The left branch had a diameter of 0.93 +/- 0.28 mm at MP1, 0.86 +/- 0.21 at MP2, and 0.6 +/- 0.07 mm at MP3. The mean length was 81.6 +/- 14.3 mm for the right and 107.0 +/- 24.9mm for the left branch. In left lateral radiographs of endoscopic retrograde pancreatography, it was not possible to differentiate the left from the right branch. Both branches ran nearly parallel and showed similar diameters but slight differences in length. The study proves that endosopic retrograde cholangio-pancreatography is possible in dogs. Radiographs taken from dogs in dorsal recumbency allow an objective assessment of the common bile duct and the accessory pancreatic duct.

Tylosin-responsive chronic diarrhea in dogs.

Fourteen dogs had shown chronic or intermittent diarrhea for more than 1 year. Diarrhea had been successfully treated with tylosin for at least 6 months but recurred when treatment was withdrawn on at least 2 occasions. Tylosin-responsive diarrhea (TRD) affects typically middle-aged, large-breed dogs and clinical signs indicate that TRD affects both the small and large intestine. Treatment with tylosin eliminated diarrhea in all dogs within 3 days and in most dogs within 24 hours. Tylosin administration controlled diarrhea in all dogs, but after it was discontinued, diarrhea reappeared in 12 (85.7%) of 14 dogs within 30 days. Prednisone given for 3 days did not completely resolve diarrhea. Probiotic Lactobacillus rhamnosus GG did not prevent the relapse of diarrhea in any of 9 dogs so treated. The etiology of TRD, a likely form of antibiotic-responsive diarrhea (ARD) is unclear. The following reasons for chronic diarrhea were excluded or found to be unlikely: parasites, exocrine pancreatic insufficiency, inflammatory bowel disease, small intestinal bacterial overgrowth, enteropathogenic bacteria (Salmonella spp., Campylobacter spp., Yersinia spp., or Lawsoni intracellularis), and Clostridium perfringens enterotoxin and Clostridium difficile A toxin. A possible etiologic factor is a specific enteropathogenic organism that is a common resident in the canine gastrointestinal tract and is sensitive to tylosin but difficult to eradicate. Additional studies are required to identify the specific cause of TRD.

Inhibition of ampicillin-induced emergence of resistance in intestinal coliforms by targeted recombinant beta-lactamase.

The aim of the present study was to determine whether oral targeted recombinant beta-lactamase (TRBL) administration could overcome the development of ampicillin-induced resistance in the gut microbiota. Eighteen laboratory beagles with permanent jejunal fistula were randomised to receive ampicillin + placebo, ampicillin + TRBL or placebo. A total of 982 coliform isolates, collected from jejunal and faecal samples before, during and after the treatment were tested against nine antimicrobials. The proportion of ampicillin resistance (multi-resistance) among coliform isolates increased from 20 to 36% in the ampicillin + placebo group but far less, 20-36%, in the ampicillin + TRBL group. These results indicate that TRBL may prevent the emergence of beta-lactam-associated resistance in coliforms in the gut.

Evaluation of serum values of pancreatic enzymes after endoscopic retrograde pancreatography in dogs.

OBJECTIVE: To assess the safety of endoscopic retrograde pancreatography (ERP) in dogs by performing repeated clinical examinations and laboratory analyses of serum amylase, lipase, canine trypsin-like immunoreactivity (cTLI), and canine pancreatic elastase 1 (cE1) after the procedure. ANIMALS: 7 healthy Beagles. PROCEDURES: Clinical examinations were performed and blood samples obtained for serum enzyme determinations before and at intervals (10 minutes; 2, 4, and 6 hours; and 1, 2, and 3 days) after ERP. RESULTS: Repeated clinical examinations revealed no signs of ERP-induced complications in the 7 dogs. Results of repeated laboratory tests indicated a transient increase in serum values of amylase, lipase, and cTLI but not cE1. Mean +/- SD lipase activity increased from 120.7 +/- 116.4 U/L to 423.4 +/- 243.1 U/L at 4 hours after ERP. Median serum cTLI concentration increased from 16.2 microg/L (range, 77 to 26.5 microg/L) to 34.9 microg/L (range, 16.6 to 68.3 microg/L) 10 minutes after ERP. Enzyme values returned to baseline levels at the latest on day 2 in 6 of 7 dogs. Highest values for serum amylase, lipase, and cTLI and their delayed return to baseline values were detected in 1 dog with contrast filling of the pancreatic parenchyma. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that ERP appears to be a safe imaging technique of pancreatic ducts in healthy dogs, although it induced a transient increase in serum values of pancreatic enzymes. In dogs, repeated clinical examinations and serum enzyme determinations can be used to monitor ERP-induced complications such as acute pancreatitis.