Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 46

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  pleuropneumonia swin
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Medycyna Weterynaryjna
|
2010
|
tom 66
|
nr 08
s.516-520,rys.,tab.,bibliogr.
The virulence factors of Actinobacillus pleuropneumoniae (App) have been described. The most important among them are: Apx toxins, proteases, lipopolysaccharides (LPS), capsule polysaccharides (CPS), outer membrane proteins and adhesins. All App strains possess CPS, which facilitates their invasion by protecting bacteria from the defense of the host immune system (phagocytosis and lysis). It also prevents the opsonization and removing of bacteria from the respiratory tract. Being a component of the external membrane, LPS induces production of the tumor necrosis factor, interleukins, interferons, activated oxygen compounds, prostaglandins, platelet activating factor and leukotrienes. Proteases released by App have the capacity of IgA cleavage and degradation of hemoglobin. These facilitate mucosal colonization and acquisition of iron ions necessary for the survival of bacteria. Actinobacillus pleuropneumoniae synthesizes four toxins: ApxI, ApxII, ApxIII and ApxIV. They have the ability to form pores in biological membranes and stimulate secretion of proinflammatory mediators. They possess hemolytic and cytotoxic capacities. Apx toxins damage endothelial cells and activate the thrombocytes which result in microclot formation leading to necrosis. Apx toxins are also highly immunogenic. They play a dominant role in the pathogenesis of swine pleuropneumonia. The lack of Apx genes definitely causes a loss of bacterial virulence. Nevertheless, other App structures may also significantly affect the course of App infection.
Many cases of pleuropneumonia were observed in pigs aged 3—4 months on an industrial farm. In order to determine an optimal procedure there was performed an experiment on three groups of pigs. Group one containing 654 young pigs aged 6 weeks was given amoxacillin for 7 days at a dose of 12 g per 100 l of water. A vaccine against pleuropneumonia was administered the second group of young pigs (660 animals). The third group (660 young pigs) was vaccinated between 8 and 11 weeks of life against pleuropneumonia and in the period between vaccinations amoxacillin was administered for 7 days at a rate of 25 g per 100 kg of feed. Each experimental group of animals was compared with a control group comprising a nearing number of animals. The best results were observed in the third group mortality of 2.6 per cent compared with 7.7 per cent of death in the control group; daily weight gains were at 7.7 per cent higher than those in controls.
In this study, methods like serotyping, biochemical schemes and antibiotic susceptibility were used to analyse 70 isolates of Actinobacillus pleuropneumoniae (App). Serological identification of App strains was performed using agglutination, precipitation and coagglutination techniques. Fifteen different tests were employed for biochemical analysis. The antibiotic susceptibility pattern was analysed using 17 chemioterapeutics. The results of the serotyping techniques have shown cross-reactions - especially between serotype 2 and 6 and serotypes 1, 9 and 11. The strongest cross-reactions were observed in the agglutination test. Among 15 biochemical reactions 8 were positive for all investigated isolates. Common features for all serotypes were: NAD-dependence, CAMP reaction, hemolysis, urease production and hydrolysis of glucose, mannitol, xylose and sucrose. The results of antibiotic susceptibility have shown that all App strains are resistant to lincomycin and streptomycin. It should be stressed that an apparent difference between Polish and German strains has been observed in terms of the scope of their sensitivity/resistance to some choosen antibiotics. Generally, no significant differences were found to exist in the antibiotic sensitivity patterns among App strains. To conclude, it should be underlined that conventional methods are useful only to a limited extent as tools for an epidemiological study of App infection in swine.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.