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PubMed1977

Selective medium for isolation of Bacteroides nodosus.

The sensitivity of Bacteroides nodosus, the causative agent of sheep foot rot, to 24 selected antimicrobial agents was tested. Many contaminants ordinarily associated with foot rot lesions were sensitive to lincomycin, whereas B. nodosus demonstrated resistance to this antibiotic. A concentration of 1 microgram of lincomycin per ml of basal medium optimally inhibited contaminants while allowing growth of B. nodosus. The basal medium was Eugon agar with 0.2% yeast extract and 10.0% defibrinated horse blood. Parallel inoculations of 31 foot rot lesion specimens onto basal medium and basal medium containing lincomycin (selective medium) were performed. B. nodosus was isolated from 16 of the specimens cultured on the selective medium and from only 3 of the specimens cultured on the basal medium. The concentration of agar in the standard Eugon medium was found to influence the growth of B. nodosus in the presence of lincomycin. Trimethoprim also exhibited potential selectivity for B. nodosus.

Agar↗
PubMed1983

Effect of pilus dose and type of Freund's adjuvant on the antibody and protective responses of vaccinated sheep to Bacteroides nodosus.

Groups of sheep were immunised twice with one or other of six vaccines consisting of purified pili from Bacteroides nodosus at three dose levels (10, 38 and 154 micrograms) and emulsified with either complete (CFA) or incomplete Freund's adjuvant (IFA). Beginning one month after vaccination the sheep were homologously challenged on irrigated pasture, with naturally transmitted foot rot for a period of 26 weeks. Statistical analyses of the number of feet per sheep with severe foot rot demonstrated that there was a significant effect of vaccinal dose but neither an adjuvant effect nor an interaction between dose and adjuvant. Similar conclusions were reached when the titres of antipilus agglutinins in the serum were analysed. By both criteria the responses to doses of 154 and 38 micrograms of pili were significantly better than to 10 micrograms, but not significantly different from each other. The IFA vaccines caused less reaction at the sites of injection than the CFA vaccines and within the former the vaccines containing 10 and 38 micrograms pilus produced less reaction than those containing 154 micrograms. Hence a vaccine containing 38 micrograms of purified pili in IFA is nearly optimal for homologous protection against severe foot rot and is acceptable in terms of the reaction at the injection site.

Agglutination Tests↗
PubMed1983

Susceptibility of Bacteroides nodosus to various antimicrobial agents.

The susceptibility of 18 strains of Bacteroides nodosus to 21 antimicrobial agents was tested in vitro. Penicillin was the most effective antibiotic tested. Other antibiotics tested, in order of relative efficacy, were cefamandole, clindamycin, tetracycline, chloramphenicol, erythromycin, sodium cefoxitin, tylosin tartrate, nitrofurazone, tinidazole, and dihydrostreptomycin sulfate. Tests of solutions of 4 antibiotics in 70% ethanol indicated that ethanol served primarily as a diluent and did not contribute substantially to the curative effect of such topical medications on foot rot lesions in sheep. Of the chemicals commonly used in foot baths for treatment of ovine foot rot, copper sulfate was most effective, followed by zinc sulfate, then formalin. Several commercial disinfectants and iodine were quite effective against B nodosus, whereas 5.25% sodium hypochlorite and 70% ethanol alone were relatively ineffective.

Animals↗
PubMed1983

Surface structure of Bacteroides nodosus in relation to virulence and immunoprotection in sheep.

A comparative electron microscopic study was made of virulent ovine strains, benign ovine strains, bovine strains and culture variants of Bacteroides nodosus using negative staining, thin section and freeze-fracture etch techniques. The plasma membrane, peptidoglycan layer and outer membrane structures were similar in all the organisms, but there were marked differences in the presence of pili, diffuse polar material and additional layer. The variations in these surface structures were examined in relation to the virulence and immunoprotection of B. nodosus towards foot-rot in sheep. Only organisms with abundant pili caused virulent foot-rot; diffuse polar material and perhaps the additional layer may also be associated with virulence, but conclusive evidence was lacking. It appeared that pili and one or more unknown cell components, possibly diffuse polar material but not the additional layer, were necessary for immunoprotection.

Animals↗
PubMed1996

A method for describing disease patterns during the life span of dairy cows.

This study presents some guidelines for describing the health status of dairy cows over their entire life span. It aims to define some types of health-paths (trajectories) described in terms of disease patterns (at the lactation level) and related to cow characteristics (breed, production potential) and farms. The data were collected over a 20-year period on three experimental farms. Eight diseases were analysed: clinical mastitis, lameness, placental retention, foot rot, digestive disorders, milk fever, metritis, and arthritis. The statistical procedures used were correspondence analysis of time-indexed tables and hierarchical ascending clustering. A total of 28 health-paths were identified and 16 of these (the most common) are described in detail. At the lactation level, eight disease patterns were defined: high incidence of disease other than mastitis (1), predominantly mastitis plus milk fever (2), predominantly foot rot (3), very low incidence of disease (4), mastitis plus digestive disorders (5), very high mastitis incidence (6), low incidence of disease (7), foot rot plus digestive disorders (8). Disease patterns 3 and 6 were more common in shorter life spans (< or = 4 lactations). Conversely, health profiles 2 and 4 were generally related to the longest life spans. These results will be included in a future model of the life span of dairy cows which will also take into account other performance parameters such as milk production and reproduction.

Aging↗
PubMed1985

Differences between breeds of sheep in their responses to Bacteroides nodosus vaccines.

In a field experiment on irrigated pasture, sheep of several breeds were vaccinated twice, subcutaneously, in the upper neck, with Bacteroides nodosus vaccine containing either depiliated cells (DC vaccine), or whole, piliated cells (WC vaccine) and the responses were measured over the following 14 weeks. DC vaccine was as effective as WC vaccine in protecting against the development of foot-rot under conditions of moderate challenge, although the WC vaccine induced significantly higher pilus agglutinating antibody titres. Foot-rot developed in significantly more vaccinated Merinos (Peppin and Saxon strains) than in Romney Marsh, Dorset Horn or Border Leicester breeds. Agglutinating antibody titres after WC vaccination were significantly lower in the Peppin Merino than in the other sheep for the first 6 weeks, while after DC vaccination the titres remained elevated longer in the Border Leicester and Saxon Merino and were significantly higher from 6 weeks onwards. Reactions at the inoculation sites were generally larger in the British breeds than in the Merinos and among the former the reactions were largest, most numerous and most frequently discharged their contents in the Dorset Horn. Bodyweight gains in all vaccinated sheep were initially reduced, compared with controls, but the differences were no longer significant after the eighth week.

Agglutination Tests↗
PubMed1995

A field study of the effect of lameness on mechanical nociceptive thresholds in sheep.

Threshold responses to a mechanical pressure test were measured in two groups of adult female sheep taken from 27 flocks in north Devon. The first group consisted of 470 healthy sheep and the second of 139 sheep suffering from obvious lameness, clinically diagnosed as foot rot. The lame sheep were assessed for the severity of the lesion and the level of lameness and assigned a score. In flocks with sheep with a severe degree of lameness, the sheep had a significantly lower threshold to a mechanical nociceptive stimulus than their matched sound controls and their thresholds remained low when tested three months later, after the apparent resolution of the foot rot lesion. In flocks where the lame sheep were less severely affected there was no difference in the threshold responses to a mechanical stimulus between the sound and lame sheep.

Analgesia↗
PubMed1981

Differentiation of Bacteroides nodosus biotypes and colony variants in relation to their virulence and immunoprotective properties in sheep.

To obtain a wider definition of variation in the virulence of Bacteroides nodosus and in the protective potency of B. nodosus vaccines, we made a comparison of the in vitro characteristics of isolates from clinical infections of sheep and cattle and of certain colony variants observed previously. Three basic colony types were distinguished: papillate or beaded (B)-type colonies were produced by fresh isolates from advanced ovine foot rot; mucoid (M)-type colonies were formed by isolates from noninvasive B. nodosus infections of the interdigital skin of sheep and cattle, and also by cultures of some primary B-type colonies passaged nonselectively in vitro; and circular (C)-type colonies were formed by B. nodosus that eventually predominated in repeatedly passaged liquid subcultures. Each type could be maintained by selective agar subculturing; one strain was thus passaged 40 times as the B-type colony, at which point the organisms induced severe foot rot in experimentally infected sheep. Cultures of M-type colonies were uniformly less pathogenic and those of C-type colony organisms were avirulent. In vitro changes from prototype B-type colonies to M- and C-variants were nonreversible in these experiments, were accelerated in liquid cultures, and wee accompanied by a diminution in elastase activity of the organisms and in their immunoprotective properties against homologous challenge. Strains differed in their stability to these changes; therefore the choice of an appropriate strain and colony type may be an important consideration in studies of B. nodosus virulence and in the development of effective vaccines.

Animals↗
PubMed1978

The occurrence, prevalence and transmission of Bacteroides nodosus infection in cattle.

Following reports of findings of ovine foot-rot flora in the feet of cattle, a study was undertaken to determine the prevalence of Bacteroides nodosus infection in the apparently normal cattle population. We found that 34.5 to 74.2 per cent of the animals examined on different farms had B nodosus present in one or more feet. B nodosus was not the most prevalent bacterium observed in smears from cattle. Other Gram negative species including Fusiformis necrophorus and many Gram positive cocci and coccobacilli were also present. Macroscopic lesions in the interdigital skin characterised by erosion and hyperkeratosis were usually associated with the occurrence of B nodosus. B nodosus isolated from cattle induced mild interdigital dermatitis in experimental cattle and sheep and the infection was transmitted to recipient cattle and sheep under field conditions. Virulent foot-rot of sheep was not transmitted to recipient cattle in conditions where the disease spread to susceptible sheep.

Animals↗
PubMed1992

Humoral responses to a multivalent vaccine in age-matched lambs of different bodyweight and nutrition.

K-agglutination, pilus-enzyme-linked immunosorbent assay (ELISA) and outer membrane protein-ELISAs were used to assess humoral responses after vaccination with a commercial, multivalent, ovine foot rot vaccine (Dichelobacter nodosus whole cells) in three groups of nine-month-old lambs of markedly different bodyweight, nutritional history and dietary protein supply. Mean bodyweights of lambs in low (L), medium (M) and high (H) bodyweight/nutrition groups were 22, 32 and 48 kg, respectively, at the time of vaccination. Few significant differences in humoral responses to vaccine antigens were found between groups. However, lambs in group H tended to have lower levels of antibody to a greater number of component antigens than did lambs in the other groups. These results suggest that low bodyweight due to poor nutrition is unlikely to affect the response of sheep to multivalent foot rot vaccines.

Agglutination Tests↗
PubMed1990

Receptor changes in the spinal cord of sheep associated with exposure to chronic pain.

There is evidence that post-injury hypersensitivity is partly due to changes in the central nervous system. Sheep with foot rot were used to investigate the effect of chronic pain on some receptors thought to be involved in spinal nociceptive processing systems (alpha 2 adrenoceptor and mu and delta opioid receptors). Saturation binding studies showed a variable distribution of [3H] clonidine (alpha 2 adrenoceptor agonist) in the spinal cord of normal sheep. The number of receptors (Bmax) present in areas thought to be involved in nociceptive processing, laminae I and II and lamina X, increased to 131% and 169% of control sheep values respectively in animals exposed to chronic pain. The affinity of the receptors (KD), however, remained unchanged at approximately 2 nM. There was less [3H]DAGO (mu opioid agonist) and [3H]DPDPE (delta opioid agonist) binding in the sheep spinal cord. Both opioid receptor types being mainly located in the superficial dorsal horn. The [3H]DPDPE binding was unchanged in the sheep with foot rot, whilst the number (Bmax), but not the affinity, of the [3H]DAGO binding sites increased in laminae I and II in lame animals to 130% of the control sheep values. Hence, in animals in chronic pain, the number of alpha 2 adrenoceptors and mu opioid receptors increased mainly in areas of the sheep spinal cord associated with nociception.

Animals↗
PubMed1986

[Properties of Bacteroides nodosus isolated from cattle].

A total of five strains of Bacteroides nodosus were isolated from cattle with interdigital dermatitis on a number of farms. With regard to their cultural and morphologic properties and response to carbohydrates these strains did not differ from B. nodosus strains that caused foot rot in sheep. However, their K-antigen was different from the one of the B. nodosus strains isolated from sheep with foot rot as established via the hemagglutination test. No antigenic variations were found with the strains isolated from cattle. The tests with the proteolytic activity of the isolated strains showed that it was considerably lower than the activity of the strains isolated from sheep.

Animals↗
PubMed1978

IgG1 and IgG2 immunoglobulins to Bacteroides (Fusiformis) nodosus protease in infected and immunized sheep.

Sheep experimentally infected with foot rot developed antibodies that neutralized the proteolytic activity of Bacteroides nodosus culture filtrates in vitro. Similar antibody activity developed in sheep vaccinated against foot rot. In both cases the antibody was initially only associated with the IgG2 fraction of serum, but with time there was an increase in the proportion associated with IgG1. A subsidiary protein peak devoid of antiprotease activity was observed in elution profiles of affected and vaccinated sheep.

Animals↗
PubMed1997

Studies of wound myiasis among sheep and goats in North Sinai Governorate, Egypt.

Myiasis of man and animals is a real welfare problem of world wide distribution particularly in animal raising countries. Studies of myiasis of sheep and goats in North Sinai resulted in the identification of 21 species of myiasis producing flies. The predominant species was Musca domestica followed by Lucilia sericata and the least abundant was M. albina. In general, sheep were more infested with wound myiasis than goats. The overall infestation rate was high in summer, followed by spring then autumn. The least rate of infestation was winter. As to the different areas examined, the high rate of infestation was in Bir Al-Abd, followed by Al Hasanah, Al Arish, Al Sheikh-Zowaid and lastly Rafah. The factors predisposing to wound myiasis in a descending order of importance in goats were open wound, shearing wound, caseous lymphadenitis, foot rot, faecal staining, ophthalmo or facial eczema, horn fracture, rumen fistula and lastly posterior paralysis. In sheep, the most important cause was caseous lymphadenitis followed by foot rot, then open wound and faecal staining, shearing wound, and ophthalmo or facial eczema otherwise more or less the same as in goats. It is concluded that myiasis among edible animals is a problem of veterinary and economic importance. The clinical features range between mild annoyance to severely disfiguring or fatal. No doubt, poor hygiene, presence of draining wounds, depressed level of farmers' consciousness and immobility presidose to different anatomic types of myiasis which may extend to man.

Animals↗
PubMed1994

Characterization of a basic serine proteinase (pI approximately 9.5) secreted by virulent strains of Dichelobacter nodosus and identification of a distinct, but closely related, proteinase secreted by benign strains.

An extracellular serine proteinase with a PI approximately 9.5 (referred to as 'basic proteinase') was purified to homogeneity, from strains of Dichelobacter nodosus that cause virulent foot-rot, by gel filtration of concentrated culture supernatant on Sephadex G-100 and chromatography on sulphopropyl-Sephadex C-25 at pH 8.6 D. nodosus strains that cause benign foot-rot do not secrete a corresponding basic proteinase with a pI of approximately 9.5. Benign strains secrete a closely related, but distinct, proteinase which has the same molecular mass and N-terminal sequences as the 'virulent' basic proteinase, but a lower pI of approximately 8.6. The basic proteinases from both strains appear to interact with other proteins present in the culture medium, which results in anomalous behavior on gel filtration. Pure D. nodosus 'virulent' basic proteinase has a molecular mass of 36 kDa and showed a low solubility at I < 0.05 precipitating quantitatively from solution as microcrystals. The proteinase shows optimal activity at pH 8.0 and is stable to heating to 55 degrees C for 30 min, but at higher temperatures activity is rapidly lost. Bivalent-metal ions (e.g. Ca2+) are required to maintain the structural integrity and stability of the proteinase; in the presence of EDTA or conditions that cause protein unfolding, the proteinase undergoes rapid and complete autolysis. Cleavage of oxidized insulin A- and B-chain showed that the basic proteinase has a broad specificity, including cleavage at lysine and arginine bonds.

Amino Acid Sequence↗
PubMed2002

Cephalosporins in veterinary medicine - ceftiofur use in food animals.

Cephalosporins are an important class of antibacterial agents in use today for both humans and animals. Four generations of cephalosporins have evolved, all of which contain the beta-lactam sub-structure first found in penicillin. The range of cephalosporins available for use in food-producing animals, which is the subject of this review, is limited compared to humans. A few first- and second-generation cephalosporins are approved worldwide strictly for treatment of mastitis infections in dairy cattle. A third-generation cephalosporin, ceftiofur, and a fourth-generation cephalosporin, cefquinome, have been developed strictly for veterinary use. Cefquinome has been approved in several countries for the treatment of respiratory disease in cattle and swine, foot rot in cattle and for mastitis in dairy cattle. Ceftiofur has worldwide approvals for respiratory disease in swine, ruminants (cattle, sheep and goats) and horses and has also been approved for foot rot and metritis infections in cattle. Ceftiofur has also been approved in various countries for early mortality infections in day-old chicks and turkey poults. This review summarizes cephalosporin use in general terms, and provides an overview of ceftiofur, in terms of its spectrum of activity, indications, metabolism, and degradation in the environment. The safety of ceftiofur is also reviewed, with respect to food-animal residues, rapid metabolism and degradation, and non-persistence of ceftiofur in the environment. The environmental fragility of cephalosporins have not been explored generally, but may be an important characteristic of this antibiotic class with respect to safety of use in animals.

Animals↗
PubMed2005

Fusobacterium necrophorum infections in animals: pathogenesis and pathogenic mechanisms.

Fusobacterium necrophorum, a Gram-negative, non-spore-forming anaerobe, is a normal inhabitant of the alimentary tract of animals and humans. Two subspecies of F. necrophorum, subsp. necrophorum (biotype A) and subsp. funduliforme (biotype B), have been recognized, that differ morphologically, biochemically, and biologically. The subsp. necrophorum is more virulent and is isolated more frequently from infections than the subsp. funduliforme. The organism is an opportunistic pathogen that causes numerous necrotic conditions (necrobacillosis), either specific or non-specific infections, in a variety of animals. Of these, bovine liver abscesses and foot rot are of significant concern to the cattle industry. Liver abscesses arise with the organisms that inhabit the rumen gaining entry into the portal circulation, and are often secondary to ruminal acidosis and rumenitis complex in grain-fed cattle. Foot rot is the major cause of lameness in dairy and beef cattle. The pathogenic mechanism of F. necrophorum is complex and not well defined. Several toxins or secreted products, such as leukotoxin, endotoxin, hemolysin, hemagglutinin, proteases, and adhesin, etc., have been implicated as virulence factors. The major virulence factor appears to be leukotoxin, a secreted protein of high molecular weight, active specifically against leukocytes from ruminants. The complete nucleotide sequence of the leukotoxin operon of F. necrophorum has been determined. The operon consists of three genes (lktBAC) of which the second gene (lktA) is the leukotoxin structural gene. The leukotoxin appears to be a novel protein and does not share sequence similarity with any other leukotoxin. F. necrophorum is also a human pathogen and the human strains appear to be different from the strains involved in animal infections.

Journal Article↗