Helicobacter spp. in the saliva, stomach, duodenum and faeces of colony dogs.

The role of Helicobacter spp. infection in canine gastrointestinal disease is unclear and routes of transmission are of epidemiological and zoonotic importance. The aim of this study was to identify Helicobacter spp. in the saliva, stomach, duodenum and faeces of dogs using a multiplex PCR, and to evaluate any attendant histopathological changes. Helicobacter canis was the most common species detected in saliva and faeces and no correlation between the presence of Helicobacter spp. and histopathological changes in either the stomach or duodenum was observed. All dogs examined were co-infected with up to four species of the organism. This is the first time these bacteria have been studied at species level at multiple sites within the canine alimentary tract.

Occurrence of methicillin-resistant Staphylococci in surgically treated dogs and the environment in a Swedish animal hospital.

OBJECTIVES: To investigate whether hospitalised dogs treated surgically may become culture positive for methicillin-resistant Staphylococcus pseudintermedius or methicillin-resistant Staphylococcus aureus. METHODS: Surgically treated dogs (n=45) were sampled for methicillin-resistant Staphylococcus pseudintermedius or methicillin-resistant Staphylococcus aureus on admission, before and after surgery and at the time of removal of surgical stitches. The hospital environment (n=57), including healthy dogs in the veterinary hospital environment (n=34), were sampled for methicillin-resistant Staphylococcus pseudintermedius or methicillin-resistant Staphylococcus aureus. Genetic variations among methicillin-resistant Staphylococcus pseudintermedius or methicillin-resistant Staphylococcus aureus isolates were identified through detection of restriction fragment polymorphisms. RESULTS: No dogs developed a wound infection due to methicillin-resistant Staphylococcus pseudintermedius or methicillin-resistant Staphylococcus aureus. However, there was a significant increase in the number of dogs carrying methicillin-resistant Staphylococcus pseudintermedius after hospitalisation compared to admission (P<0·001). No methicillin-resistant Staphylococcus aureus was isolated from dogs, but was present in the environment. Methicillin-resistant Staphylococcus pseudintermedius isolates were recovered from environmental surfaces and hospitalised animals, but not from healthy dogs. Methicillin-resistant Staphylococcus pseudintermedius isolates representing nine different restriction endonuclease digestion patterns were found, with two of these occurring in both the environment and on dogs. CLINICAL SIGNIFICANCE: Dogs may contract methicillin-resistant Staphylococcus pseudintermedius in association with surgery and hospitalisation. Resistant bacteria may be transmitted between dogs, staff and the environment. Dogs colonised with methicillin-resistant Staphylococcus pseudintermedius may be a source for hospital- and community-acquired infections.

Clinical, radiological and pathological features of 12 Irish setters with canine leucocyte adhesion deficiency.

The clinical, radiological and pathological findings in 12 dogs with canine leucocyte adhesion deficiency (CLAD) from six litters are described. All the dogs were younger than 15 weeks at admission, all had been febrile and 11 had been treated with antibiotics. Seven had been treated for omphalophlebitis. At admission, all had gingivitis, lymph node enlargement and profound neutrophilia. Ten dogs were radiographed and showed various skeletal lesions compatible with metaphyseal osteopathy, craniomandibular osteopathy and osteomyelitis. Four dogs had clinical signs of respiratory distress and seven exhibited a mild interstitial pneumonia at necropsy. Six dogs had skin wounds, with strikingly few neutrophils seen on stained sections. All dogs were euthanased before six months of age due to severe and incurable infections. The clinical signs, radiological features and haematology were strongly suggestive of CLAD. The diagnosis was confirmed by granulocyte function tests and flow cytometry, which revealed impaired adhesion, impaired C3b-mediated phagocytosis and absence of adhesion proteins CD11b/CD18.

A missense mutation in the beta-2 integrin gene (ITGB2) causes canine leukocyte adhesion deficiency.

Canine leukocyte adhesion deficiency (CLAD) is a fatal immunodeficiency disease found in Irish setters. The clinical manifestations of CLAD are very similar to LAD in humans and BLAD in cattle, which are both caused by mutations in ITGB2 encoding the leukocyte integrin beta-2 subunit (CD18). Sequence analysis of the ITGB2 coding sequence from a CLAD dog and a healthy control revealed a single missense mutation, Cys36Ser. This cysteine residue is conserved among all beta integrins, and the mutation most likely disrupts a disulfide bond. The mutation showed a complete association with CLAD in Irish setters and was not found in a sample of dogs from other breeds. The causative nature of this mutation was confirmed by transduction experiments using retroviral vectors and human LAD EBV B-cells. The normal canine CD18 formed heterodimers with the human CD11 subunit, whereas gene transfer of the mutant CD18 resulted in very low levels of CD11/CD18 expression. The identification of the causative mutation for CLAD now makes it possible to identify carrier animals with a simple diagnostic DNA test, and it forms the basis for using CLAD as a large animal model for the development and evaluation of clinical treatments for human LAD.

Granulocyte function in dogs experimentally infected with a Swedish granulocytic Ehrlichia species.

Granulocyte function was studied in six dogs inoculated with a Swedish granulocytic Ehrlichia species and in four control dogs. Whole blood chemiluminescence (CL) was enhanced in the dogs with granulocytic ehrlichiosis. Both CL after stimulation with zymosan and spontaneous CL was significantly increased at peak of infection compared with pre-infection levels. Ingestion of FITC-labelled serum-opsonized yeast cells was high and stable in both groups. The ingestion was lower when the yeast cells were opsonized with anti-yeast IgG. However, there was no difference between groups. The labelling intensity of anti-human CD11b, CD18 and CD32 mAb on the granulocytes in dogs with ehrlichiosis was similar to that in control dogs. The opsonic activity in serum collected at the peak of infection was not different from serum drawn prior to inoculation. Opsonic activity was investigated both by yeast cell ingestion and by chemiluminescence after stimulation with zymosan. The serum from infected dogs enhanced the respiratory burst without stimulation with zymosan of leukocytes from healthy dogs. This suggests that serum at the peak of infection contains granulocyte activators. In this study we found normal phagocytosis together with evidence of enhanced oxidative metabolism in the granulocytes from dogs with granulocytic ehrlichiosis.

The effect of prednisolone on canine neutrophil function: in vivo and in vitro studies.

The in vivo effect of a therapeutic dose of prednisolone on canine neutrophil adherence, random migration, chemotaxis, phagocytosis of IgG and C3b opsonized yeast cells, chemiluminescence, Fc- and CR3-receptor expression was investigated. Prednisolone was also added in vitro to neutrophils as isolated cells and in whole blood. In the in vivo study, prednisolone increased the IgG mediated ingestion of yeast cells and the number of activated neutrophils in the phagocytosis assay, while flow cytometric investigation of the IgG-receptor Fc gamma RIII with a monoclonal antibody showed similar expression before, during and after treatment. Prednisolone also increased the ingestion of C3b-opsonized yeast cells, while the expression of CR3-receptors (CD11b CD18) measured by flow cytometry was unchanged. Chemiluminescence and the chemotactic response towards zymosan activated serum were increased, while adherence to nylon wool was decreased. The in vitro studies revealed that prednisolone had no or a dampening effect on neutrophils in cell suspensions. Adherence as well as IgG mediated ingestion was decreased at the highest prednisolone concentration (800 ng/ml) in whole blood. The present study suggests that the part of the antiinflammatory effect of corticosteroids mediated through their influence on neutrophils, besides reduced adherence, may be exerted by increased clearance of microorganisms and IgG-complexes through an elevated functional capacity.

Detection of antinuclear antibodies by indirect immunofluorescence in dog sera: comparison of rat liver tissue and human epithelial-2 cells as antigenic substrate.

Rat liver sections and a human epithelial cell line (HEp-2) were compared as substrates for the detection of antinuclear antibodies (ANA) in the serum of normal dogs and dogs with suspected autoimmune disease, using a standard indirect immunofluorescence (IIF) technique. Antibody reactivity against rat hepatocyte nuclei was frequently found at low serum dilutions in normal dog sera. Using rat liver sections, a minimum significant positive titer, allowing negativity in more than 95% of normal dog sera, was found to be 1/100. With this titer, ANA positivity could be verified in 64 of 112 (57%) reanalysed serum samples from dogs with suspected autoimmune disease, earlier determined as ANA-positive. No reactivity against nuclei of HEp-2 cells was observed in any of the normal dog sera analyzed at a screening dilution of 1/25. Using this dilution as a minimum significant positive titer, 63 of the 112 (56%) re-evaluated serum samples were positive. These 63 samples were from the same dogs as the 64 samples that were positive on rat liver sections. Thus, the 2 methods of ANA-IIF detected a nearly identical population of dogs with suspected autoimmune disease once the level of significance of a positive titer was adjusted to > 95% specificity for each method. HEp-2 cells were found to be superior to rat liver cryostate sections as ANA substrate because of their low reactivity with normal sera, and the ease of discernment of the ANA fluorescence pattern. The recognition and documentation of specific pattern types may give clues to ANA subspecificities, which could prove useful if they are found to correlate with well-defined subgroups of immune mediated clinical diseases in dogs.

Methods for evaluation of the adhesive and phagocytic capacities of porcine granulocytes.

The adhesive and phagocytic properties of porcine neutrophils were studied. Blood samples were collected from healthy crossbreed pigs, and granulocytes were obtained by density centrifugation. Adhesion to nylon wool was studied and expression of adhesion molecules was determined by flow cytometry. Three monoclonal antibodies showed reactivity with porcine cells and were thus subsequently used. Freezing and storage at -70 degrees C did not cause major alterations in the expression of adhesion molecules. The kinetics of phagocytosis of serum- and IgG-opsonized yeast cells were studied with fluorescence microscopy and flow cytometry. The influence of various concentrations of normal pooled and heat-inactivated pooled porcine serum on the phagocytic process was elucidated. The phagocytic process was completed more rapidly using C3b- than IgG-opsonized yeast cells. The neutrophils both attached to and ingested the serum-opsonized yeast cells to a large extent. When IgG or heat-inactivated serum were used, only minor attachment was observed. These methods for studies of neutrophil functions can be used both for the diagnosis of immunological disorders and for physiological studies of the neutrophil functions in the pig.

Canine neutrophil adhesion proteins and Fc-receptors in healthy dogs and dogs with adhesion protein deficiency, as studied by flow cytometry.

Murine monoclonal anti-human antibodies directed against neutrophil adhesion protein receptors CD35, CD18, CD11b, CD11c and the Fc-receptors CD64 (Fc gamma RI), CD32 (FC gamma RII) and CD16 (Fc gamma RIII) were evaluated regarding their ability to bind to the canine homologues. The antibodies against CD35, CD18, CD11b, CD11c and CD16 could be used to evaluate the expression of canine homologues. The routine of using frozen cells and thereby avoiding methodological errors, when samples are stained at different times, was evaluated by comparison of receptor expression in frozen and fresh samples from the same dogs. All receptors were expressed consistently on the cell surface on frozen and fresh neutrophils with the exception of CD16, which showed decreased expression in frozen cells. The expression of CD11c on neutrophils from dogs with canine leucocyte adhesion deficiency (CLAD) was analyzed and there was no difference in receptor expression between CLAD-puppies and healthy controls. CD11b/CD18 expression on neutrophil samples from three parents of CLAD-puppies, i.e. heterozygotes, did not differ from receptor expression in normal controls. Analysis of the Fc-receptor expression on neutrophils from CLAD-puppies showed that the expression of CD16 tended to be decreased in patients compared with controls.

Leucocyte adhesion protein deficiency in Irish setter dogs.

Investigation of 12 Irish setter puppies from six litters with severe recurrent infections, neutrophilia and low body weight revealed a leucocyte adhesion protein deficiency with a total lack of CD11b and CD18. Their neutrophil function was severely impaired with a totally absent capacity to ingest C3b-opsonized particles, a significantly impaired capacity to ingest IgG-opsonized particles and significantly diminished adherence to nylon wool when compared with neutrophils from healthy control dogs. The chemiluminescence of patient neutrophils activated by C3b-opsonized particles was, consequently, significantly decreased compared with that of control neutrophils, while the respiratory burst assayed by phorbolmyristate acid (PMA) stimulated nitroblue tetrazolium (NBT)-reduction was normal in the patient group. Random migration and chemotactic responses of patient and control neutrophils, were similar. The etiology, pathogenesis and clinical manifestations of the Irish setter leucocyte adhesion deficiency were similar to that of the leucocyte adhesion deficiency in humans.

Chemiluminescence and chemotaxis assay of canine granulocytes: a methodological study.

Chemiluminescence (CL) of isolated granulocytes and of whole blood from dogs was evaluated. Chemiluminescence of whole blood samples created an undesired quenching effect by the red blood cells which makes the assay difficult to apply in pathological cases with low formation of oxygen metabolites. This problem was avoided when chemiluminescence was determined, using isolated granulocytes. A cell concentration of 5 x 10(9)/l was needed to create optimal conditions. The Boyden chamber technique was used for study of random migration and chemotaxis. Casein (0.1%), zymosan activated serum with and without epsilon-amino-n-caproic-acid and homologous serum were effective chemoattractants for canine granulocytes, while FMLP (formyl-methionyl-leucyl-phenylalanin) did not attract canine granulocytes.

Phagocytosis induced by yeast cells in canine granulocytes: a methodological study.

A phagocytic function assay of canine granulocytes was established. This method allows the proportion of active granulocytes to be estimated as well as the number of adhered and ingested yeast cells. The influence of different factors on phagocytosis was studied. Temperature variation within the interval 36-41 degrees C did not affect phagocytosis. The incubation time for optimal phagocytosis of yeast cells was 35 min. The opsonization procedure giving the optimal phagocytosis was purified IgG and serum together.