Quality-control ranges for antimicrobial susceptibility testing by broth dilution of the Brachyspira hyodysenteriae type strain (ATCC 27164T).

There are no approved standards for antimicrobial susceptibility testing of the fastidious spirochete Brachyspira hyodysenteriae. An interlaboratory study was performed to establish MIC quality control ranges for six antimicrobial agents for the type strain of B. hyodysenteriae using broth dilution. The results showed that B. hyodysenteriae B78T ATCC 27164T is a suitable quality control strain. This is a first step toward standardization of methods regarding this anaerobe.

Assessment of diagnostics and antimicrobial susceptibility testing of Brachyspira species using a ring test.

There is no ring test for quality assessment available in Europe for diagnostics and antimicrobial susceptibility testing of the fastidious, anaerobic bacteria of the genus Brachyspira. Therefore, an international ring test for Brachyspira spp. was performed once a year during 2002-2004. Two sets of coded samples were prepared and distributed on each occasion. One set comprised six swabs dipped in pig faeces spiked with Brachyspira spp. intended for diagnostics. The other set comprised two pure strains intended only for susceptibility testing. All methods used were in-house methods. The species used were Brachyspira hyodysenteriae, Brachyspira pilosicoli, Brachyspira innocens, Brachyspira murdochii and Brachyspira intermedia. In most cases, the correct Brachyspira spp. were detected. However, the results showed that Brachyspira spp. could be difficult to identify, especially if two Brachyspira spp. were mixed or if the concentration of Brachyspira in faeces was low. Additionally, some laboratories reported Brachyspira growth in control samples that were not seeded with any spirochaetes. The lowest detection level was 10(2) bacteria/ml faeces for both B. hyodysenteriae and B. pilosicoli. The susceptibility tests performed showed that disc diffusion was not recommendable for Brachyspira spp. Extended antimicrobial dilution series gave most congruent results. The diversity of the results highlights the importance of ring tests for a high quality of diagnostics and antimicrobial susceptibility tests for Brachyspira spp. This is the first ring test described for Brachyspira spp.

Persistence of orally administered Salmonella enterica serovars Agona and Montevideo in Atlantic salmon (Salmo salar L.).

The objective of our experiments was to study the persistence and dissemination of orally administered Salmonella in smoltified Atlantic salmon. In experiment 1, salmon kept at 15 degrees C were fed for 1 week with feed contaminated with 96 most-probable-number units of Salmonella Agona per 100 g of feed and then starved for 2 weeks. Samples were taken from the gastrointestinal tract and examined for Salmonella 1, 2, 8, 9, 15, and 16 days after the feeding ended. In experiment 2, Salmonella Agona and Montevideo were separately mixed with feed and administered by gastric intubation. Each fish received 1.0 x 10(8), 1.0 x 10(6), or 1.0 x 10(4) CFU. The different groups were kept in parallel at 5 and 15 degrees C and observed for 4 weeks. Every week, three fish in each group were sacrificed, and samples were taken from the skin, the pooled internal organs, the muscle, and the gastrointestinal tract and examined for the presence of Salmonella. The results from the two experiments showed that the persistence of Salmonella in the fish was highly dependent on the dose administered. Salmonella was not recovered from any of the fish that were fed for 1 week with the lowest concentration of Salmonella. In the fish given the highest dose of Salmonella, bacteria persisted for at least 4 weeks in the gastrointestinal tract as well as, to some extent, the internal organs. The present study shows that under practical conditions in Norway, the risk of Salmonella in fish feed being passed on to the consumer of the fish is negligible.

Acute toxoplasmosis in three wild arctic foxes (Alopex lagopus) from Svalbard; one with co-infections of Salmonella Enteritidis PT1 and Yersinia pseudotuberculosis serotype 2b.

Acute disseminated toxoplasmosis was diagnosed in three wild arctic foxes (Alopex lagopus) that were found dead in the same locality on Svalbard (Norway). The animals included one adult female and two 4-months-old pups. The adult fox was severely jaundiced. Necropsy revealed multifocal, acute, necrotizing hepatitis, acute interstitial pneumonia, and scattered foci of brain gliosis, often associated with Toxoplasma tachyzoites. One pup also had Toxoplasma-associated meningitis. In addition, the latter animal was infected with Yersinia pseudotuberculosis serotype 2b and Salmonella Enteritidis phage type 1 (PT1), which may have contributed to the severity of the Toxoplasma infection in this animal. The diagnosis of toxoplasmosis was confirmed by positive immunohistochemistry and detection of anti-Toxoplasma gondii antibodies in serum of all foxes. The animals were negative for Neospora caninum, canine distemper virus, canine adenovirus, and rabies virus on immunolabelling of tissue sections and smears.

Screening of feral pigeon (Colomba livia), mallard (Anas platyrhynchos) and graylag goose (Anser anser) populations for Campylobacter spp., Salmonella spp., avian influenza virus and avian paramyxovirus.

A total of 119 fresh faecal samples were collected from graylag geese migrating northwards in April. Also, cloacal swabs were taken from 100 carcasses of graylag geese shot during the hunting season in August. In addition, samples were taken from 200 feral pigeons and five mallards. The cultivation of bacteria detected Campylobacter jejuni jejuni in six of the pigeons, and in one of the mallards. Salmonella diarizona 14: k: z53 was detected in one graylag goose, while all pigeons and mallards were negative for salmonellae. No avian paramyxovirus was found in any of the samples tested. One mallard, from an Oslo river, was influenza A virus positive, confirmed by RT-PCR and by inoculation of embryonated eggs. The isolate termed A/Duck/Norway/ 1/03 was found to be of H3N8 type based on sequence analyses of the hemagglutinin and neuraminidase segments, and serological tests. This is the first time an avian influenza virus has been isolated in Norway. The study demonstrates that the wild bird species examined may constitute a reservoir for important bird pathogens and zoonotic agents in Norway.

Campylobacter spp., Salmonella spp., verocytotoxic Escherichia coli, and antibiotic resistance in indicator organisms in wild cervids.

Faecal samples were collected, as part of the National Health Surveillance Program for Cervids (HOP) in Norway, from wild red deer, roe deer, moose and reindeer during ordinary hunting seasons from 2001 to 2003. Samples from a total of 618 animals were examined for verocytotoxic E. coli (VTEC); 611 animals for Salmonella and 324 animals for Campylobacter. A total of 50 samples were cultivated from each cervid species in order to isolate the indicator bacterial species E. coli and Enterococcus faecalis / E. faecium for antibiotic resistance pattern studies. Salmonella and the potentially human pathogenic verocytotoxic E. coli were not isolated, while Campylobacter jejuni jejuni was found in one roe deer sample only. Antibiotic resistance was found in 13 (7.3%) of the 179 E. coli isolates tested, eight of these being resistant against one type of antibiotic only. The proportion of resistant E. coli isolates was higher in wild reindeer (24%) than in the other cervids (2.2%). E. faecalis or E. faecium were isolated from 19 of the samples, none of these being reindeer. All the strains isolated were resistant against one (84%) or more (16%) antibiotics. A total of 14 E. faecalis-strains were resistant to virginiamycin only. The results indicate that the cervid species studied do not constitute an important infectious reservoir for either the human pathogens or the antibiotic resistant microorganisms included in the study.

Risk factors for Campylobacter infection in Norwegian cats and dogs.

Rectal swabs from healthy cats and dogs, and from dogs and cats with clinical diarrhoea were collected approximately every third month from May 2000 to June 2001 from six small-animal practices throughout Norway. A questionnaire was filled in for each animal. Of the 301 healthy cats sampled, 54 (18%) were positive for Campylobacter, compared to 5 out of 31 (16%) cats with diarrhoea. Campylobacter jejuni was isolated from 11 (3%), C. upsaliensis from 42 (13%) and C. coli from 2 (0.6%) of the cats sampled. Isolates from four cats (1%) could not be specified. Of the 529 healthy dogs, 124 (23%) were positive for Campylobacter, compared to 18 of 66 (27%) dogs with diarrhoea. C. jejuni was isolated from 20 (3%) and C. upsaliensis from 117 (20%) of the dogs sampled. Isolates from five dogs (0.8%) could not be specified. Eighteen out of the 20 investigated C. upsaliensis samples were resistant to streptomycin. The clinically healthy animals were included in the analysis to identify factors associated with Campylobacter prevalence. The cat model had low classification ability. The dog-data model indicated increased odds of infection with Campylobacter for dogs

No association found between the ascites syndrome in broilers and feeding of oats contaminated with deoxynivalenol up to thirty-five days of age.

This study investigated the possible effects of feeding broilers oats that were naturally contaminated with deoxynivalenol (DON) on development of the ascites syndrome. Four groups of 240 birds were fed complete feed mixtures with graded amounts of contaminated oats giving from .1 (control) to 3.4 mg DON/kg feed. The broiler chickens were 1 d old at start of trial and were slaughtered at Day 35. Performance and carcass quality were not affected by the mycotoxin in the diets. No clinical signs of ascites or occurrence of other treatment-related lesions were detected.

The effects of naturally deoxynivalenol-contaminated oats on the clinical condition, blood parameters, performance and carcass composition of growing pigs.

A feeding trial with naturally deoxynivalenol (DON)-contaminated oats included in feed mixtures at graded levels was conducted in growing pigs. The DON concentrations were 0, 0.7, 1.7, and 3.5 mg/kg of complete feed mixture given ad libitum to different groups. The data recorded were feed consumption, body weight gain, slaughter weight, biochemical and haematological data including serum immunoglobulin A, clinical condition and post-mortem pathology including histopathology. Significantly decreasing body weight gain throughout the experimental period, decreased slaughter weight and reduced feed utilization efficiency were observed for the group fed a diet containing 3.5 mg/kg of DON. At the same DON concentration, there were increased liver weights and decreased concentrations of serum protein and albumin, and a temporary fall in packed blood cell volume, serum calcium and serum phosphorus. For the groups fed diets containing 1.7 and 3.5 mg/kg of DON, a statistically significant, dose-related decrease in daily feed consumption was observed. No other effects on haematological, biochemical or immunological parameters were recorded. The carcass quality was not affected in any group. It was concluded that significant effects in growing pigs may be observed at a dietary DON concentration of 1.7 mg/kg, originating from naturally contaminated oats included in a diet that was otherwise adequate and contained only minor traces of other mycotoxins.

Digital necrobacillosis in Norwegian wild tundra reindeer (Rangifer tarandus tarandus).

Outbreaks of digital necrobacillosis in Norwegian wild tundra reindeer (Rangifer tarandus tarandus) are described. The outbreaks occurred in late summer and autumn 2007 and 2008, subsequent to periods with an unusually high number of days with precipitation and high air temperature. Lesions were generally restricted to one foot and the disease incidence was highest in calves. Single limbs from 20 animals and six whole carcasses were submitted for laboratory examination. Gross lesions were characterized by swelling of the fetlock to coronary band area and cutaneous sinus tracts with sparse discharge of pus. Subcutaneous tissue was inflamed and oedematous with focal necrosis. Tendons, tendon sheaths, joints and periosteum of the digital bones were often affected. Animals shot during winter showed severe chronic periostitis and osteomyelitis and necrotizing deforming arthritis. Microscopically, skin lesions were characterized by deep ulcers with centrally located necrotic tissue, bordered by a zone of oedema and intense inflammation with granulation tissue and fibrosis. Necrosis, suppurative inflammation and oedema were found in the synovial membranes, tendons and tendon sheaths. Digital bone lesions were characterized by necrosis, fibrosis and extensive bone proliferation. Vasculitis and thrombosis were common in all lesions. Elongate filamentous gram-negative bacteria in necrotic lesions from all animals were identified as Fusobacterium necrophorum by fluorescence in-situ hybridization. F. necrophorum was cultured from the foot lesions of six animals. Five of these isolates were examined by 16S rRNA sequencing. The sequences were identical and differed from all other strains listed in GenBank. These results are consistent with circulation of a reindeer-adapted pathogenic strain of F. necrophorum in the wild reindeer population, causing outbreaks of digital necrobacillosis following warm and humid summers.

Effects of feeding deoxynivalenol-contaminated oats on reproduction performance in White Leghorn hens.

1. The effect of feeding trichothecene-contaminated diets with graded concentrations of deoxynivalenol ranging from 120 to 4900 micrograms/kg to groups of laying hens was investigated. 2. Food intake, weight gain and egg production were not affected by mycotoxin administration. No significant differences were found between groups. 3. The overall results from the hatching tests did not reveal any significant differences in fertility, hatchability or perinatal mortality, which could be explained by the mycotoxin content in the diets. 4. Body weight at hatching and viability of the chicks were not affected by the mycotoxin concentrations in the diets. 5. The incidence of chick developmental anomalies was increased in the mycotoxin-administered groups compared to controls. Minor malformations were the dominating anomalies and included unwithdrawn yolk sac and delayed ossification. The most frequent major malformations were cloacal atresia and cardiac anomalies.

Effects of diets with graded levels of deoxynivalenol on performance in growing pigs.

Feeding trials were conducted to evaluate the effect of including deoxynivalenol (DON)-contaminated oats to provide approximately 0.5, 1.0, 2.0 and 4.0 mg/kg in the complete diets of growing pigs with initial weight of 25 kg. Performance was recorded as weight gain, feed intake, efficiency of feed utilization and carcass quality. Restricted feeding was compared to ad libitum feeding. For the groups fed diets containing 2 and 4 mg/kg of DON, a dose-related decrease in weight gain was observed during the first 8 weeks on experimental diets. With 4 mg/kg DON there were decreased feed intake, weight gain and efficiency of feed utilization throughout the experiment. No effect was observed in groups fed diets containing 0.5 or 1.0 mg/kg of DON. The carcass quality was not affected in any group.

Ochratoxin A in plasma of Norwegian swine determined by an HPLC column-switching method.

A method well suited for screening large numbers of plasma samples for ochratoxin A is presented. Proteins were precipitated with methanol and the supernatant diluted with 0.01 M phosphoric acid before 1 ml extract was injected into a high-performance liquid chromatograph (HPLC). The extract was further cleaned up and pre-concentrated on a polystyrene-divinylbenzene precolumn. After column-switching, the sample was chromatographed on a C18 analytical column, and ochratoxin A was detected with a fluorescence spectrophotometer, either directly or after postcolumn pH shift. The detection limit was 0.10 ng ochratoxin A/ml plasma. The method was used to determine the ochratoxin A concentration in 216 samples of swine plasma. They were collected from different herds in June 1991 from ten slaughterhouses, located in different parts of Norway. Eighty-two percent of the samples contained > or = 0.10 ng ochratoxin A/ml plasma while 0.9% contained > or = 5.0 ng/ml.