METHODOLOGICAL APPROACHES REGARDING BACTERIOLOGICAL DIAGNOSTICS OF ACTINOBACILLUS PLEUROPNEUMONIA INFECTION IN PIGS
Introduction. Actinobacillus pleuropneumoniae (App) is an infectious disease of pigs characterized by hemorrhagic and necrotizing pneumonia and fibrinous pleurisy. The acute course is manifested by fever and septicemia, the chronic - by depletion and growth retardation of pigs. The disease is highly contagious, different serotypes can circulate in one herd. APP is one of the most common bacterial respiratory diseases of pigs, which is registered in almost all countries in the world engaged in pig breeding. The goal of the work is to present a clear sequence of bacteriological studies performed by us for the Actinobacillus pleuropneumoniae bacteria detection, methodological approaches and results interpretation. Materials and methods. The research was conducted in the laboratory of bacterial diseases of animals of the Institute of Veterinary Medicine of NAAS, as well as in a number of pig farms of Ukraine where respiratory bacterial diseases of pigs registering (10 farms). The material for the study was biomaterials from sick, compulsorily slaughtered and dead piglets of different age groups. The subject of the study were pigs, white mice; pig blood, strains, isolates of microorganisms; biomaterials in vivo and from dead piglets. Results of research and discussion. Bacteriological diagnosis of APP was established on the basis of the results of bacteriological studies of pathological material from dead and compulsorily slaughtered animals, as well as a biological sample. Material for the study was taken no later than 4-6 hours after slaughter/death of animals, from 2-3 carcasses of piglets that had at autopsy characteristic signs of APP and were not treated with antibiotics. Bacteriological examination was performed in the appropriate sequence. The surface of the lungs, lymph nodes and other pathological materials was burned with a spatula, the pulp was collected in a Pasteur pipette, it was transferred into a test tube with 1-2 cm<sup>3</sup> of Meat Peptone Agar, mixed and corked. To grow on a nutrient media, coccobacillus need a specific growth factor - diphosphopyridine nucleotide (V-growth factor). The pathogen grows well on modified PPLO-agar, Mueller Hinton Chocolate Agar II, Columbia agar with the addition of NAD. Culturing on nutrient media should be carried out no later than 24 hours after pathological material sampling. When satellite hemolytic (presence of β-hemolysis zone) colonies were found, Gram and Gins stained smears were prepared from them. The culture was determined as pathogenic in cases of death of at least 2 white mice within 24-72 hours, followed by bacteriological examination of the pathological material and subsequent isolation of the culture of the pathogen. As an additional study disks with saponin - 750 μg/disk, bacitracin - 10 μg/disk, erythromycin - 15 μg/disk, azithromycin - 15 μg/disk were used to identify actinobacillus. Conclusions and prospects for further research. As a result of the conducted researches the sequence of research is described, methodical instructions concerning bacteriological diagnosis of APP of pigs are developed and improved, the scheme of researches is presented, cultures of Actinobacillus pleuropneumoniae from pathological material are isolated. Given that we have proven the prevalence of APP in pigs in domestic farms, bacteriological examination for the presence of its pathogen remains relevant.