Detection of portal and systemic bacteremia in dogs with severe induced hepatic disease and multiple portosystemic shunts

OBJECTIVE: To determine existence of portal and systemic bacteremia in dogs with induced severe hepatic disease, compared with clinically normal dogs, before and after vena caval banding. ANIMALS: 6 control dogs and 10 dogs with induced severe hepatic disease and multiple portosystemic shunts (PSS). PROCEDURE: Dogs of the diseased group were given dimethylnitrosamine (2 mg/kg of body weight, PO) twice weekly until multiple PSS developed. Surgery was performed on dogs of both groups, and blood for baseline aerobic and anaerobic bacterial culture was collected from catheters placed in the portal and hepatic veins and caudal vena cava. All dogs underwent vena caval banding, and blood for aerobic and anaerobic bacterial culture was collected from the portal and hepatic venous catheters at 120, 240, and 360 minutes after banding. RESULTS: Compared with control dogs (16% gram-positive and 84% gram-negative bacteria), diseased dogs had significantly higher percentage of gram-positive bacteria (42% of positive culture results, P < or = 0.01) and significantly lower percentage of gram-negative bacteria (58% of positive culture results, P < or = 0.01) isolated. Pseudomonas aeruginosa was isolated most frequently from dogs of both groups; more than 1 organism was isolated from 5 dogs of each group. Antimicrobial susceptibility included that to aminoglycosides (particularly amikacin), fluorinated quinolones, and imipenem. CONCLUSION: Portal and systemic, predominantly gram-negative, bacteremia is present in catheterized, clinically normal dogs and dogs with dimethylnitrosamine-induced hepatic disease and multiple PSS.     

Bacterial culture of blood from critically ill dogs and cats: 100 cases (1985-1987)

Of 100 critically ill dogs and cats, 49 (39 dogs, 10 cats) had bacteremia. Gram-negative bacilli were the most common isolates from the bloodstream of dogs with bacteremia (46%), and gram-positive cocci and anaerobic bacteria were isolated from 36% and 31% of positive cultures, respectively; 15% of positive cultures were polymicrobial. In cats, gram-negative bacilli (especially Salmonella enteritidis) and anaerobic bacteria were the most common isolates, and 30% of positive cultures were polymicrobial. Gram-positive cocci were not isolated from the blood-stream of cats. Odds ratios, adjusted for the combined effects of disease status (severe vs nonsevere), results of bacterial culture of blood result (positive vs negative), and species (dog vs cat) were calculated for mortality in animals in the study. In animals with bacteremia, severe disease increased the risk of death 11.6-fold, compared with the risk in animals with nonsevere disease. Bacteremia increased mortality 10-fold in animals with severe disease, compared with mortality in animals with severe disease without bacteremia. Animals with severe disease and bacteremia were 15.6 times more likely to die than were those with nonsevere disease and negative culture results. In animals with nonsevere disease, culture results (positive vs negative) were not related significantly to mortality. Disease status (severe vs nonsevere) in animals without bacteremia also was not significantly related to mortality. There was no significant difference in overall mortality in dogs, compared with that in cats.(ABSTRACT TRUNCATED AT 250 WORDS)     

The microbial environment of the ear canal in health and disease

Otitis externa is an important disease of dogs and, to a lesser degree, cats. The yeast Malassezia canis is the most common organism demonstrated in ear infections. Coagulase-positive staphylococci are the most common bacteria isolated, often occurring with M. canis. Pseudomonas aeruginosa and Proteus are gram-negative bacteria that are frequently encountered. Other bacteria, such as beta-hemolytic streptococci, enterococci, Escherichia coli, and Corynebacterium are also important. Malassezia canis, coagulase-positive staphylococci, and Pseudomonas aeruginosa commonly occur as monoinfections, whereas other bacteria are typically associated with mixed infections. Smears may provide rapid diagnosis on which to base empiric treatment. Cultures should be considered in recurrent or refractory cases, especially those involving gram-negative bacteria. In practices that are not equipped to perform culture and susceptibility tests, it is advisable to seek the advice of a microbiology laboratory.     

Comparison of bacteriologic culture of blood and necropsy specimens for determining the cause of foal septicemia: 47 cases (1978-1987)

Diagnosis of bacterial septicemia was confirmed by results of bacteriologic culture of antemortem blood samples and/or necropsy specimens obtained from 47 foals up to 8 days old. Gram-negative bacteria were isolated from all 47 foals, and mixed infections with more than one organism were involved in 26 (55%). Escherichia coli, Actinobacillus spp, and Klebsiella pneumoniae were the most frequent isolates, infecting 55, 34, and 23% of foals, respectively. Gram-positive bacteria and anaerobic bacteria were isolated only from foals with mixed infections with gram-negative organisms. Clostridium perfringens was the only anaerobe isolated. In 38 (81%) of 47 foals with confirmed septicemia, blood samples were culture-positive. Thirty-two septicemic foals subsequently died, allowing a comparison to be made between the species of bacteria isolated by culture of blood with those recovered by culture of internal organs at necropsy. Blood failed to yield any gram-negative organisms in 12 (37.5%) of 32 foals from which a gram-negative pathogen was isolated at necropsy. Forty-three percent of the gram-negative bacteria, including 59% of the E coli, and 10% of the gram-positive bacteria found in septicemic foals at necropsy were not detected earlier by results of bacteriologic culture of blood.     

Bacterial Isolates From Plaque and From Blood During and After Routine Dental Procedures in Dogs

Objective — This study evaluates the association between dental procedures and bacteremia in dogs, including a comparison of bacteria isolated from plaque and blood, severity of the bacteremia versus the severity of dental disease, and the longevity of bacteremia.
Study Design — Bacteria cultured from the blood over time were compared with those isolated from the plaque and crevicular fluid and in relation to severity of dental disease.
Animals or Sample Population — Twenty adult greyhounds.
Methods — Blood samples were collected for culture before induction of general anesthesia, immediately after intubation, 20 minutes after initiation of the dental procedure, and at 10-minute intervals until 10 minutes after the dental procedure was completed. Samples of plaque were taken for microbiological culture.
Results — Sixty to ninety percent of the bacterial genera isolated from the plaque were present in the blood. Dogs classified according to severity of dental disease showed no difference in the total number of different species or number of different Gram-negative, Gram-positive, or anaerobic bacteria isolated from plaque or blood (P <.05). Bacteremia was present in all of the dogs studied, within 40 minutes from the initiation of the dental procedure, regardless of the severity of oral disease.
Conclusions — Gram-negative, Gram-positive, and anaerobic bacteria are present in blood during dental procedures; the bacteremia can persist beyond the dental procedure, and is not associated with the severity of dental disease.
Clinical Relevance — The nature and extent of bacteremia occuring during routine dental procedures is important in understanding a potential risk to dogs.     

Oxidative burst and phagocytic activity of phagocytes in canine parvoviral enteritis

Canine parvoviral enteritis (CPE) is a severe disease characterized by systemic inflammation and immunosuppression. The function of circulating phagocytes (neutrophils and monocytes) in affected dogs has not been fully investigated. We characterized the functional capacity of canine phagocytes in CPE by determining their oxidative burst and phagocytic activities using flow cytometry. Blood was collected from 28 dogs with CPE and 11 healthy, age-matched, control dogs. Oxidative burst activity was assessed by stimulating phagocytes with opsonized Escherichia coli or phorbol 12-myristate 13-acetate (PMA) and measuring the percentage of phagocytes producing reactive oxygen species and the magnitude of this production. Phagocytosis was measured by incubating phagocytes with opsonized E. coli and measuring the percentage of phagocytes containing E. coli and the number of bacteria per cell. Complete blood counts and serum C-reactive protein (CRP) concentrations were also determined. Serum CRP concentration was negatively and positively correlated with segmented and band neutrophil concentrations, respectively. Overall, no differences in phagocyte function were found between dogs with CPE and healthy control dogs. However, infected dogs with neutropenia or circulating band neutrophils had decreased PMA-stimulated oxidative burst activity compared to healthy controls. Additionally, CPE dogs with neutropenia or circulating band neutrophils had decreased PMA- and E. coli–stimulated oxidative burst activity and decreased phagocytosis of E. coli compared to CPE dogs without neutropenia or band neutrophils. We conclude that phagocytes have decreased oxidative burst and phagocytic activity in neutropenic CPE dogs and in CPE dogs with circulating band neutrophils.     

Phagocytic and nitroblue tetrazolium reductive properties of mature and immature neutrophils and eosinophils from blood and bone marrow from cows

Functional capabilities of morphologically mature (segmented) and immature granulocytes (neutrophils and eosinophils) from bone marrow from cows were studied and compared with similar activities of segmented granulocytes from blood. Phagocytosis of Escherichia coli and postphagocytic oxidative metabolic stimulation, measured by nitroblue tetrazolium (NBT) reduction, were evaluated simultaneously. Phagocytosis was observed readily in segmented neutrophils, neutrophilic bands, and metamyelocytes and rarely in myelocytes. Phagocytosis was not seen in promyelocytes and myeloblasts. Neutrophilic bands and metamyelocytes were phagocytically less active than were segmented neutrophils. Washed segmented bone marrow neutrophils possessed phagocytic activity similar to that of blood neutrophils, whereas the activity of unwashed segmented bone marrow neutrophils was markedly less than that of blood neutrophils. Reduction of NBT was observed only in blood segmented neutrophils and bone marrow segmented neutrophils; the magnitude of NBT reduction was significantly (P = less than 0.005) less in bone marrow neutrophils than in blood neutrophils. Eosinophils were phagocytically less competent than were neutrophils. The NBT reduction was observed only in eosinophils from blood, but not in eosinophils from bone marrow.     

Prevalence and Identity of Translocating Bacteria in Healthy Dogs

Bacterial translocation is characterized by the passage of intestinally derived bacteria across the intestinal mucosa to local or regional tissues. This phenomenon is believed to be important in the pathogenesis of gram-negative bacteremia and septicemia; however, the pathway or route of translocation remains unclear. To define the route of translocation better, mesenteric lymph nodes from 50 apparently healthy dogs undergoing elective ovariohysterectomies were cultured aerobically and anaerobically. The aims of this study were to determine the prevalence of bacterial translocation and to quantify and identify types of organisms found in mesenteric lymph nodes. Peripheral blood and portal blood samples were similarly cultured to rule out hematogenous organisms as a source of lymph node contamination. Bacteria were isolated from mesenteric lymph nodes of 26 dogs (52%). The number of bacteria varied from 50 to > 10⁵ organ-isms/g of tissue. Bacteria isolated included Staphylococcus intermedius (n = 3), coagulase-negative Staphylococcus (n = 2), nonhemolytic Streptococcus (n = 4), Bacillus species (n = 5), Escherichia coli (n = 6), Salmonella species (n = 3), Pseudomonas species (n = 2), Enterococcus species (n = 2), Clostridium sordelli (n = 1), Micrococcus species (n = 1), Lactobacillus species (n = 1), and Propionibacterium acnes (n = 1). One of 50 peripheral blood samples yielded an unidentified gram-positive coccus and a coagulase-negative Staphylococcus. No bacteria were isolated from portal blood samples of any dog. Further studies of this type on sick dogs are warranted before clinical recommendations can be made to culture mesenteric lymph nodes routinely.     

Clinical and microbiologic findings in dogs with bronchoscopically diagnosed tracheal collapse: 37 cases (1990-1995).

OBJECTIVE: To investigate the role of bacteria in bronchoscopically diagnosed tracheal collapse in dogs by evaluating qualitative results of bacteriologic cultures. DESIGN: Retrospective study. ANIMALS: 37 dogs with tracheal collapse. PROCEDURE: Clinical records for dogs with tracheal collapse confirmed with bronchoscopy were reviewed. A protected catheter brush was used to obtain samples for bacteriologic culture from the large airways. RESULTS: Results of bacterial culture were negative for 5 of 29 dogs. For 24 dogs, 1 (n = 10), 2 (6), or > or = 3 (8) species of bacteria were isolated. Pseudomonas spp were isolated most frequently (17/29), and a single Pseudomonas sp grew in 7 samples. Other bacteria included Enterobacter spp (4/29), Citrobacter spp (3/29), and Moraxella spp, Klebsiella spp, Bordetella spp, or Acinetobacter spp (2/29 dogs each). Anaerobic and aerobic cultures yielded positive results in samples from 2 dogs. Cytologic results were available for 13 dogs with positive results of bacteriologic culture; epithelial cells were reported most commonly. Five samples had a small number of neutrophils; bacteria were identified cytologically in 2 of 5 samples that contained neutrophils. Bacteria were also seen in 2 samples that lacked inflammatory cells. CONCLUSIONS AND CLINICAL RELEVANCE: Bacteria are commonly isolated from samples obtained via airway brushing in dogs with tracheal collapse; however, in the absence of cytologic confirmation of inflammation or infection, an association between bacteria and clinical signs of tracheal collapse cannot be established.     

Comparison of polymerase chain reaction with bacterial 16s primers to blood culture to identify bacteremia in dogs with suspected bacterial endocarditis

Background: Identification of the bacterial organism in dogs with endocarditis is challenging. Human studies have reported the utility of the polymerase chain reaction (PCR) to amplify and identify bacterial nucleic acid from infected valvular tissue and blood. Hypothesis/Objectives: We hypothesized that PCR using primers designed to amplify the bacterial 16s gene would identify circulating bacteria in dogs with suspected bacterial endocarditis more consistently than standard blood culture techniques. Animals: Eighteen dogs with suspected bacterial endocarditis based upon clinical and echocardiographic findings. Fifteen clinically normal dogs served as negative controls. Methods: Prospective study of dogs evaluated for suspect endocarditis at 6 veterinary hospitals. A blood sample was drawn from all dogs and evaluated with both a single‐sample PCR and standard 3‐sample blood culture techniques. Results: Blood culture identified noncontaminant bacteria in 6/18 study animals (33%) and 1 control dog; PCR identified noncontaminant bacteria in 7/18 study animals (39%). There were no study animals in which the 2 tests identified different bacteria (κ= 1.0). However, bacteria were identified by both techniques in only 2/18 study animals. When results from both PCR and blood culture were considered together, a noncontaminant bacterial organism was identified in 11/18 study animals (61%). Conclusion and Clinical Importance: The results of this study suggest that although single sample PCR with 16s primers was not more sensitive than blood culture for detection of bacteremia in dogs with suspect endocarditis, performing both techniques simultaneously did increase the likelihood of identification of bacteria in blood.     

Cardiovascular infections in dogs: epizootiology, clinical manifestations, and prognosis

Bacteremia in dogs was found to be more prevalent than suspected and Staphylococcus aureus, Escherichia coli, and beta-hemolytic streptococci were the most commonly isolated microbes. Administration of glucocorticoids was the most common predisposing cause of infections. Subacute and chronic bacteremia often followed integumentary infections such as abscesses, cellulitis, and infected wounds and was usually the result of gram-positive microbes. Peracute and acute bacteremia was associated with internal infections and was usually the result of E coli. Many dogs with bacteremia had unusual or multisystemic signs similar to those observed with immune-mediated diseases. Hypotension, tachycardia, and weakness were features of gram-negative bacteremia, whereas gram-positive bacteremia had more chronic signs and tended to develop into diskospondylitis. The adequacy of treatment, type of bacteremia, source of infection, and delay before treatment influenced the course of illness. Cephalosporins and gentamicin were most effective against all types of bacteremia.     

Temporal study of staphylococcal species on healthy dogs

During a 1-year period, specimens were obtained monthly from 5 hair coat and 7 mucous membrane sites of 11 healthy dogs. Among 804 isolates of staphylococci, 13 species were identified. Staphylococcus intermedius was the most frequently isolated (40.2% of total isolates) coagulase-positive species, and S xylosus was the most frequently isolated (17.3%) coagulase-negative species. Moreover, S intermedius was the most frequently isolated species from the 12 sites evaluated and was isolated persistently from 8 of the 9 dogs that completed the 1-year study. On the basis of a commercial identification system, 14 profile numbers were identified for isolates of S intermedius. However, 2 profile numbers accounted for a majority (70.9%) of the isolates. Specific S intermedius biotypes identified on the basis of hemolysis, coagulase production, beta-lactamase activity, and antimicrobial susceptibility patterns were found repeatedly in 3 dogs. Seemingly, S intermedius was a resident of the normal bacterial microflora of these dogs; however, the inability to isolate S intermedius from 1 dog during the study year indicated that not all dogs harbor S intermedius as a resident microorganism.     

Antimicrobial resistance in staphylococci from animals with particular reference to bovine Staphylococcus aureus, porcine Staphylococcus hyicus, and canine Staphylococcus intermedius.

Besides their role as commensals on the skin and mucosal surfaces, staphylococci may be involved in a wide variety of diseases in animals. Staphylococcal infections in animals are mainly treated with antimicrobial agents and as a consequence, staphylococci from animal sources have developed and/or acquired resistance to the respective antimicrobial agents. Resistance statistics obtained from national monitoring programmes on staphylococci from cattle and pigs, but also from surveillance studies on staphylococci involved in diseases in dogs are reported and reviewed with regard to their comparability. This review mainly focusses on the genetic basis of antimicrobial resistance in staphylococci of animal origin. Particular attention is paid to resistance to those antimicrobial agents which are most frequently used in veterinary medicine, but also to antimicrobial agents, such as chloramphenicol and mupirocin, which are used in specific cases for the control of staphylococcal infections in pets and companion animals. In addition, plasmids and transposons associated with the respective resistance properties and their ways of spreading between members of the same or different staphylococcal species, but also between staphylococci and other gram-positive bacteria, are described.     

Ability of hematologic and serum biochemical variables to differentiate gram-negative and gram-positive mastitis in dairy cows

Medical records of 142 dairy cows with clinical mastitis were examined to determine whether hematologic or serum biochemical results could be used to distinguish between mastitis episodes caused by gram-negative bacteria (n = 78) from those caused by gram-positive bacteria (n = 64). Signalment, historic information, hematologic and serum biochemical results, milk culture results, and outcome (discharged from hospital or died) were obtained from the medical records. Cows with gram-negative mastitis had significantly (P < .01) lower blood leukocyte, segmented neutrophil, monocyte, and lymphocyte counts and had higher blood hemoglobin concentrations and hematocrits than did cows with gram-positive mastitis. Serum urea nitrogen was the only serum biochemical result associated with pathogen type, and it was higher in cows with gram-negative mastitis than in those with gram-positive mastitis. Mortality rate (25% overall) did not differ between groups. Logistic regression indicated that routine hematologic analysis (segmented neutrophil count, monocyte count, and hemoglobin concentration) was an accurate predictor of gram-negative mastitis, with a sensitivity of .93, a specificity of .89, and an overall accuracy of 91%. The values for sensitivity and specificity were higher than those previously reported for clinical tests differentiating mastitis episodes caused by gram-negative bacteria from those caused by gram-positive bacteria. Our results indicate that routine hematologic analysis is useful for predicting pathogen type in dairy cows with clinical mastitis, thereby facilitating treatment decisions.     

Prevalence of coagulase-negative staphylococci in bovine mastitis in Zimbabwe

This study was carried out to determine the prevalence of coagulase-negative staphylococci in clinical and subclinical mastitis in commercial and small-scale farms in Zimbabwe. Thirty five quarter milk samples from clinical mastitis cases and 371 quarter milk samples from cows with subclinical mastitis were cultured for bacterial pathogens. The most frequent pathogens isolated in clinical mastitis were the enteric bacteria (31.4%), followed by coagulase negative staphylococci (22.9%) and then Staphylococcus aureus (17.1%), whereas in subclinical mastitis S. aureus (34.2%) and coagulase-negative staphylococci were (33.2%) the most common. Bacillus species were only isolated in milk samples from subclinical mastitis. Coagulase-negative staphylococci were observed in mixed infections with other bacteria in only 2.2 of the 406 milk samples from clinical and subclinical mastitis where they were isolated together with Bacillus species in 6 of the 9 mixed infection cases. About 95% of the milk samples from which 131 coagulase-negative staphylococci were isolated had correspondingly high somatic cell counts. The coagulase-negative staphylococci isolated most frequently were S. chromogenes (7.9%), S. epidermidis (7.4%) and S. hominis (5.9%). They were all associated with high somatic cell counts. All the coagulase-negative staphylococci isolates were susceptible to cloxacillin and erythromycin, and more than 90% of the isolates were susceptible to neomycin, penicillin and streptomycin. The highest resistance was to tetracycline (17.6%), followed by lincomycin (13.7%). About 8% of the isolates were resistant to both penicillin and streptomycin.     

Validation of the Sysmex XT‐2000iV hematology system for dogs,cats, and horses. II. Differential leukocyte counts

Background: The Sysmex XT‐2000iV is a laser‐based, flow cytometric hematology system that stains nucleic acids in leukocytes with a fluorescent dye. A 4‐part differential is obtained using side fluorescence light and laser side scatter. Objective: The purpose of this study was to validate the Sysmex XT‐2000iV for determining differential leukocyte counts in blood from ill dogs, cats, and horses. Methods: Blood samples from diseased animals (133 dogs, 65 cats, and 73 horses) were analyzed with the Sysmex XT‐2000iV (Auto‐diff) and the CELL‐DYN 3500. Manual differentials were obtained by counting 100 leukocytes in Wright‐stained blood smears. Results: Leukocyte populations in the Sysmex DIFF scattergram were usually well separated in equine samples, but were not as well separated in canine and feline samples. Correlation among the Sysmex XT‐2000iV, CELL‐DYN 3500, and manual counts was excellent for neutrophil counts (r ≥.97) and good for lymphocyte counts (r ≥.87) for all three species. Systematic differences between the 3 methods were seen for lymphocyte and monocyte counts. The Sysmex reported incomplete differential counts on 18% of feline, 13% of canine, and 3% of equine samples, often when a marked left shift (>10% bands) and/or toxic neutrophils were present. Eosinophils were readily identified in cytograms from all 3 species. Neither the Sysmex nor the CELL‐DYN detected basophils in the 7 dogs and 5 cats with basophilia. Conclusions: The Sysmex XT‐2000iV automated differential leukocyte count performed well with most samples from diseased dogs, cats, and horses. Basophils were not detected. Immature neutrophils or prominent toxic changes often induced errors in samples from cats and dogs.     

Bacteremia and bacterial translocation in the naturally occurring canine gastric dilatation-volvulus patient

This prospective study was performed to determine the prevalence of bacteremia in the naturally occurring gastric dilatation-volvulus (GDV) patient, the possible relationship between bacteremia and survival, and whether bacteremia was a result of translocation from the stomach. Blood cultures were collected from each patient. Bacterial cultures were collected from the liver, mesenteric lymph node, and stomach. Forty-three percent of the GDV cases and 40% of the controls developed positive blood cultures. Gram-negative rods were the most frequently isolated organisms. Evidence of bacterial translocation from the stomach could not be demonstrated in GDV patients, and survival was not affected by the presence of bacteremia.     

Case-control study of blood type, breed, sex, and bacteremia in dogs with immune-mediated hemolytic anemia

OBJECTIVE: To determine whether blood type, breed, or sex were risk factors for immune-mediated hemolytic anemia (IMHA) in dogs and whether bacteremia was common in dogs with IMHA. DESIGN: Case-control study. ANIMALS: 33 dogs with IMHA, 1,014 dogs without IMHA for which blood type (dog erythrocyte antigens 1.1, 1.2, 3, 4, 5, and 7) was known, 15,668 dogs without IMHA for which breed was known, and 15,589 dogs without IMHA for which sex was known. PROCEDURE: Blood type, breed, and sex distribution of dogs with IMHA were compared with data for control dogs with Fisher exact tests and by calculating odds ratios (ORs). Results of bacterial culture of blood samples were documented for dogs with IMHA, when available. RESULTS: Dog erythrocyte antigen 7 was associated with a significant protective effect (OR, 0.1) in Cocker Spaniels with IMHA (n = 10), compared with control dogs. Cocker Spaniels, Bichon Frise, Miniature Pinschers, Rough-coated Collies, and Finnish Spitz had a significantly increased risk of IMHA, as did female dogs (OR, 2.1). Blood samples from 12 dogs with IMHA were submitted for bacterial culture, and none had bacteremia. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that blood type, breed, and sex may play a role in IMHA in dogs.     

Neutrophil activation associated with increased neutrophil acyloxyacyl hydrolase activity during inflammation in cattle.

Acyloxyacyl hydrolase (AOAH) is a lysosomal enzyme found in neutrophils and macrophages that acts to partially deacylate the lipid-A component of the endotoxin of gram-negative bacteria rendering it less toxic, yet maintaining much of its immunostimulatory potential. We have found that the activity of neutrophil AOAH per cell increased during localized inflammation. The purpose of this study was to determine the mechanism(s) responsible for these increases in neutrophil AOAH activity. Because changes in neutrophil maturity commonly are associated with inflammation, intravascular infusion of purified gram-negative bacterial lipopolysaccharide and SC injection of bovine recombinant granulocyte colony-stimulating factor was used to induce large numbers of circulating immature neutrophils. Immature neutrophils were found to have AOAH activity equal to that of mature cells; however, when neutrophils were stimulated in vitro with known activators, AOAH activity of activated cells was more than that of unstimulated cells. The increase in AOAH activity was inversely related to prestimulation activity. Increases in AOAH activity after neutrophil activation were not a result of de novo synthesis of the enzyme, because cycloheximide did not prevent activation-induced increases in activity.     

Antimicrobial resistance in Staphylococcus spp., Escherichia coli and Enterococcus spp. in dogs given antibiotics for chronic dermatological disorders, compared with non-treated control dogs

The aim of this study was to evaluate antimicrobial resistance in canine staphylococci, Escherichia coli and enterococci, which were isolated from 22 dogs with pyoderma and a history of previous antibiotic treatment, compared to bacterial isolates from 56 non-treated control dogs. Two isolates of each bacterial species per dog were investigated, if detected. Staphylococcal isolates from dogs with pyoderma (35 isolates) were more resistant to sulphatrimethoprim than the isolates from controls (56 isolates) (57% vs. 25%, p < 0.004). Multiresistance in staphylococci was also more common in dogs with pyoderma (29% vs. 9%, p = 0.02). A similar trend among isolates of E. coli was detected (24 and 74 isolates from treated and control dogs, respectively), but the differences were not significant. Resistance for macrolide-lincosamides was approximately 20% among staphylococci in both groups. Resistance to ampicillin among enterococci was 4%-7%. The age of the dogs might have an impact on resistance: multiresistance among staphylococcal isolates from younger dogs (< or = 5 years) was more common than in older dogs (26 years) (24%, vs. 0%, 63 and 27 isolates, respectively, p = 0.02). Staphylococci in younger dogs were more resistant to tetracycline (48% vs. 11%, p < 0.001) and sulphatrimethoprim (48% vs. 15%, p < 0.01) than those in older dogs. In contrast, the isolates of E. coli from older dogs tended to be more resistant, although a significant difference was detected only in resistance to tetracycline (13% vs. 2% of 40 and 50 isolates respecthely, p = 0.04)). The results of this small study indicate that resistance in canine staphylococci in the capital area of Finland is comparable with many other countries in Europe. Resistance in indicator bacteria, E. coli and enterococci, was low.