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Biomedical subjects

M Bisgaard

Publications and source records attributed to M Bisgaard.

At least 73 records · Page 4Linked to original sources
PubMed1996

Differentiation of Salmonella gallinarum and Salmonella pullorum by their whole-cell fatty acid methyl ester profiles.

The whole-cell fatty acid methyl ester (FAME) profiles of Salmonella (S.) gallinarum and Salmonella (S.) pullorum strains were compared in the computer-linked gas-liquid chromatography. The profiles of whole cellular FAMEs allow the separation and identification S. gallinarum and S. pullorum by the Microbial Identification System and so can be used for their differentiation.

Animals↗
PubMed1995

Influence of subclinical virus infections and other factors on broiler flock performance.

1. The influence of subclinical infections with infectious bursal disease virus, adenoviruses, REO viruses and chicken anaemia virus and of various production variables on broiler flock performance was investigated. 2. A significant effect could not be demonstrated of any of the viral infections either alone or in combination. 3. The production results were profoundly influenced by several other factors, that is, breed, diet, stock density and contents of whole wheat grain in the food. 4. The incidence of horizontally-transmitted subclinical chicken anaemia virus infection in Danish broilers has decreased significantly during the period 1988-89 to 1992-93, probably because of improved hygiene and management. The incidence of adeno- and REO virus infections did not change during the same period. 5. It is concluded that factors other than subclinical viral infections presently have an economic impact on performance observed in the Danish broiler production.

Adenoviridae Infections↗
PubMed1995

Reclassification of 30 Pasteurellaceae strains isolated from rodents.

Thirty Pasteurellaceae strains isolated from gerbil, guineapig, hamster, mouse, muskrat and rat were reinvestigated and reclassified after comparison with reference strains. Strains originally described as Pasteurella pneumotropica were reclassified as [Pasteurella] pneumotropica Heyl biotype (7), [P.] pneumotropica Jawetz biotype (1), Pasteurella dagmatis (1) or Taxon 22 (2). Strains previously reported as Actinobacillus sp. were reclassified as [P.] pneumotropica biotype Jawetz (3), P. dagmatis (3) or Taxon 6 (7). Strains earlier described as Pasteurella gallinarum were renamed as SP group pasteurella (4) or Taxon 25 (2). Some of these reclassified Pasteurellaceae have not been reported previously in rodents. The present findings underline the importance of extended characterization of isolates and comparison with references strains to avoid misclassification within the family Pasteurellaceae Pohl 1981.

Actinobacillus↗
PubMed1994

Stability of plasmids in five strains of Salmonella maintained in stab culture at different temperatures.

Four strains of Salmonella berta and one of Salm. enteritidis were stored as stab cultures in sugar-free agar at 5 degrees, 22 degrees and 30 degrees C and in 15% glycerol at -80 degrees C. The stability of the plasmid profiles in each of the strains was monitored over a period of 2.5 years. Plasmid profiles were stable in all strains stored at -80 degrees C, and only six of 450 colonies examined from strains kept in sugar-free agar at 5 degrees C had lost plasmid molecules. Seventy of 440 colonies from stab cultures that were kept at 22 degrees C, and 71 of 440 colonies at 30 degrees C showed changed plasmid profiles. The total number of plasmids lost increased with time, and occasionally, more than one plasmid molecule was lost in the same strain. The virulence associated plasmid of Salm. enteritidis was remarkably stable as it was maintained in all colonies examined at all temperatures investigated. Likewise, no change in SmaI restriction profile was observed in this plasmid molecule at any temperature.

Plasmids↗
PubMed1994

The characterization of Danish isolates of Salmonella enterica serovar Enteritidis by phage typing and plasmid profiling: 1980-1990.

Plasmid profiling, phage typing and antimicrobial resistance typing have been carried out on 736 isolates of Salmonella enterica serovar Enteritidis collected in Denmark during the period 1980 to 1990. Strains originated from cases of human salmonellosis, broiler poultry flocks, layer poultry flocks, quarantined imported poultry, environmental samples from hatchery units, and from bovines. Phage type (PT) 1 was found to be the most common type among isolates of poultry origin (57.6%) followed by PT4 (28.8%). Isolates belonging to PT8 were found exclusively in imported birds. Phage typing of a representative sample of human isolates revealed the predominance, as in most other Western European countries, of PT4 (61.8%). PT1, however, was found in 17.0% of human strains, a much higher incidence than expected. Antibiotic resistance was observed in 4 out of 107 human isolates (3.7%) and 2 out of 205 non-human isolates (1%) tested.

Animals↗
PubMed1993

Ecology and significance of Pasteurellaceae in animals.

The reservoir of eighty-one taxa/groups classified with the family Pasteurellaceae Pohl 1981 is reviewed based upon published data and own investigations. With the exception of certain strains of P. multocida, A. pleuropneumoniae and [H.] paragallinarum organisms belonging to this family are usually regarded as opportunistic, secondary invaders which under normal conditions coexist peacefully with the animal host on mucosal membranes of the upper respiratory- and lower genital tracts. Very little is known about factors that govern the ecological preferences that certain members of this family show for specific surfaces and hosts. Mechanisms of colonization, survival and multiplication, invasion and pathogenic action are incompletely understood. The significance of Pasteurellaceae in animals and man has recently been reviewed. Subsequent publications have underlined the significance of biovars 2 of P. canis and P. avium and ornithine negative P. multocida in pneumonia in cattle. In addition, differences in pathogenicity have been demonstrated for different serovars of [H.] parasuis. The disease potential of many taxa/groups is only incompletely known.

Actinobacillus↗
PubMed1993

Whole cell protein profiling of actinobacillus-like strains classified as taxon 2 and taxon 3 according to Bisgaard.

Thirty-nine strains representing all biovars established within the taxa 2 and 3 complex of Bisgaard and two strains belonging to the avian [P.] haemolytical[A.] salpingitidis complex were characterized by one-dimensional SDS-PAGE of cellular proteins. The protein patterns, which contained 40 to 45 discrete protein bands, were highly reproducible. Numerical analysis of the background protein patterns obtained resulted in six major and twelve minor groups (phena). Comparison of the phena defined by protein profiling with species/groups previously established by DNA: DNA hybridization, chemotyping and "biotyping" showed that the best correlation existed between DNA:DNA hybridization and "biotyping". A correlation between results obtained from DNA:DNA hybridization and protein profiling was not obtained. With a few exceptions, a connection was demonstrated between protein profiles and hosts from which the strains belonging to the respective phena originated.

Actinobacillus↗
PubMed1992

Occurrence of V-factor (NAD) independent strains of Haemophilus paragallinarum.

Strains of Bisgaard taxon 31, isolated from chickens in South Africa suffering from a respiratory disease with clinical symptoms and gross lesions similar to infectious coryza, showed great phenotypical similarities with Haemophilus paragallinarum infection except for NAD requirement, beta-galactosidase activity and maltose fermentation. Deoxyribonucleic acid-deoxyribonucleic acid hybridization confirmed a high level of genetic relatedness (DNA binding value, 89%) with Haemophilus paragallinarum. Guanine + cytosine content and genome size data also support the classification of taxon 31 strains within the species Haemophilus paragallinarum.

Animals↗
PubMed1992

Salmonella enterica: infection, cross infection and persistence within the environment of a broiler parent stock unit in Denmark.

A total of three hundred and ninety nine isolates of Salmonella enterica were recovered from 3106 cloacal swab cultures, chicken carcasses and environmental samples taken from a broiler breeding farm over six successive generations. S. enterica serovars Berta (S. Berta), 4,12:b:-, Taksony, Binza and Typhimurium were identified. One hundred and seventy one strains of S. Berta were analysed by plasmid profiling to determine the epidemiological relationships between isolates from each generation and from each house section of the production unit. All isolates contained plasmids; plasmids of eleven different molecular weights were identified. Eighteen different plasmid profiles were identified throughout the observation period. An increase in the diversity of plasmid profiles in each successive generation, the restriction of particular plasmids to particular houses and their persistence within that house were taken to indicate that contamination within the unit was due to persistence and cross-infection rather than to a reintroduction of serovar Berta into new generations of stock.

Animals↗
PubMed1992

Biochemical and molecular characterization of Salmonella enterica serovar berta, and comparison of methods for typing.

Strains of Salmonella enterica serovar berta (S. berta) from Denmark and seven other countries have been characterized with the aim of developing a rational typing strategy in connection with outbreak investigations. Biotyping divided the strains into H2S-positive (90%) and H2S-negative (10%) biovars. Six percent of the strains were resistant to one or more antimicrobial agents. Eighty-eight percent of the strains carried plasmids and 52 different plasmid profiles were recognized. Six of the common plasmid sizes in these profiles were shown by restriction enzyme analyses to contain more than one plasmid species. More than 90% of the strains had the same ribotype with the restriction enzymes Sma I and EcoR I and the same whole cell protein profile. Outer membrane protein profiles and isoenzyme profiles were identical in all S. berta analysed. Plasmid profiling in combination with restriction enzyme analysis of plasmids seemed to be the most rational typing strategy for S. berta. The results indicated that S. berta strains regardless of geographical source or host are possibly clonal in nature.

Animals↗
PubMed1992

Further investigations on Pasteurella multocida infections in feral birds injured by cats.

A total of 64 Pasteurella multocida strains (46 out of 11 different feral bird species, partly injured by cat bites, and 18 strains originating from clinically healthy cats) were biochemically differentiated. As a result, 67.4% of the strains from feral birds and 61.1% from the cats were classified as the subspecies multocida, whilst 21.7% and 27.8% were identified as the subspecies septica. The percentage of frequency for both the subspecies was of a comparable order of magnitude from the birds injured by cat bites and from cats (58.6% and 61.1%, 24.1% and 27.8% resp.), whereas the frequency from other feral birds differed considerably (82.4% and 17.6%). Maltose-positive strains were only demonstrable in birds with wounds inflicted by cats. To date, maltose-positive strains have only been obtained from one cat and one human being with an injury caused by a cat. The results of this investigation confirm the possibility of the direct transmission of Pasteurella multocida via cat bites. 19 strains from feral birds and 15 strains from cats were tested for their capability to produce toxins. The results of these tests were negative. The present paper also describes the pathologic-anatomical and histopathological lesions caused by the infection in feral birds.

Animals↗
PubMed1992

Plasmid profiles as an epidemiological marker in Salmonella enterica serovar berta infections. Comparison of isolates obtained from humans and poultry.

Plasmid profiles of 674 Salmonella berta strains isolated in the period 1985-1989 from 674 cases of human infections were recorded. Five hundred and eighty-nine of the strains examined (87.4%) contained plasmids and the mean number of plasmids was 1.8 per strain. Sixteen different plasmid sizes were recognized, 13 of which had also been reported from S. berta of poultry origin. The plasmids formed 90 different profiles. Forty-five of these profiles, comprising 90.7% of isolates, had previously been recorded among poultry strains. Only 12 human isolates (1.8%) carried plasmids which were not demonstrated among isolates obtained from broilers. The prevalences of the 20 most commonly demonstrated profiles were not significantly different among isolates obtained from humans and broilers. The average difference between the prevalences of individual plasmid profiles was 2.1, with a standard deviation of 4.2. Based on the results, indications are that broilers represent the main reservoir for human S. berta infections in Denmark.

Animals↗
PubMed1991

Reclassification of German, British and Dutch isolates of so-called Pasteurella multocida obtained from pneumonic calf lungs.

The taxonomic relationship of 131 strains previously identified as Pasteurella multocida obtained from calf pneumonia in West Germany, United Kingdom and Netherlands was investigated by extended phenotypic and limited genotypic characterization. Twenty-four strains were classified as P. multocida ssp. multocida, 15 strains as P. avium biovar 2 and 13 strains as P. canis biovar 2. Sixty-five and five strains were tentatively classified as ornithine negative P. multocida ssp. multocida and P. multocida ssp. septica, respectively. Genetic investigations showed that ornithine negative strains of P. multocida were related on species level. Less genomic binding was found between an ornithine negative strain of P. multocida ssp. septica and the type strains of the three subspecies of P. multocida. The taxonomic position of ornithine negative strains of P. multocida is still under investigation. The taxonomic position of the remaining nine strains is uncertain underlining the need for genotypic characterization within the genus Pasteurella to aid in defining single species by phenotypic tests.

Animals↗
PubMed1991

Diagnostic and treatment problems in skull base meningiomas.

Two cases of combined intra- and extracranial meningiomas are presented. It both cases the middle ear problems preceded the diagnosis by several years. The diagnosis was made in one patient because of tumor invasion of the middle ear and in the other because of tumor invesion of the nasal cevity. In both instances the diagnosis was made at a stage at which total tumor removal was considered unwarranted in the light of the paucity of symptoms. A discussion of the clinical behavior of such meningiomas is given. The vast majority of co-called primary extracrenial ectopic meningiomas are not truly primary extracranial tumors, but rather extracranial extensions of intracranial lesions. The importance of computed tomography or magnetic resonance imaging examinations in patients with long-standing middle ear problems of undiagnosed etiology is stressed.

Journal Article↗
PubMed1991

Taxon 20 (Fam. Pasteurellaceae) infections in European brown hares (Lepus europaeus).

Hemolytic bacteria, phenotypically related to organisms previously identified as Pasteurella haemolytica and tentatively named Taxon 20, were isolated from cases of purulent bronchopneumonia and from conjunctivitis in European brown hares (Lepus europaeus). The bronchopneumonia, sometimes accompanied by lesions in other organs, occurred without other concomitant disease. The conjunctivitis was found mainly in animals suffering from the European brown hare syndrome.

Animals↗
PubMed1991

Plasmid profiles of Salmonella enterica serovar berta isolated from broilers in Denmark.

Salmonella enterica serovar berta was isolated for the first time in Denmark in October 1984. This serovar has subsequently become endemic in the broiler industry. Plasmid profile analysis of 610 strains of S. berta isolated from broilers and broiler parent stock in the period October 1984 to July 1989 showed that plasmids were present in 85.7% of strains investigated, with a mean of 1.8 plasmids per strain. A significant increase in the mean number of plasmids per strain was seen during the observation period. Seventeen different plasmid sizes and 90 different plasmid profiles were identified. Plasmid profiling of S. berta appears to represent a promising tool for analysing the epidemiology of S. berta infections in broilers.

Animals↗