Studija znakova patogenosti kod Pasteurella multocida, izolirane iz životinja različitih vrsta

A significant number of microorganisms in natural and artificial environments exist in a structured formation – biofilm. This formation attaches to a certain surface, particularly the epithelium. The ability to form a similar structure has been observed in Pasteurella multocida, the causative agent of anthropozoonoses that affect domestic and wild animals, birds, companion animals and humans. The spectrum of pathogenetic action of P. multocida is wide and associated with the development of respiratory and multisystemic pathology, bacteraemia and other manifestations. Timely detection of P. multocida and treatment of the diseases it causes in farm and domestic animals is important to limit economic losses and improve social security. The main objective of this study was to determine the pathogenicity of P. multocida, its ability to form a biofilm, its resistance to antibiotics, and to identify the genes responsible for the formation of dermonecrotic toxin and biofilm formation. The paper presents the results of a study of 11 isolates of P. multocida: six isolates (54.5%) from rabbits, two isolates (18.2%) from dogs, two isolates (18.2%) from cats, and one isolate from pigs (9.2%). In all isolates, the gene ptfA was detected. This gene encodes the formation of type 4 fimbriae and participates in the formation of the biofilm, and the studied cultures in vitro formed a biofilm of different densities. The genome of eight isolates (72.7%) included the toxA gene (provides the formation of dermonecrotic toxin), while 45.4% of isolates had a complete set of the studied signs of pathogenicity, both in phenotypic (biofilm formation, mortality for laboratory animals) and genotypic (presence of toxA, ptfA) traits, and three isolates (27.3%) showed signs of multidrug resistance. The virulence of the toxA-negative isolates of P. multocida was lower than in toxA-positive isolates. The culture with the highest virulence (0.5x 101 CFU) and extreme resistance to antibiotics formed a biofilm of the highest density. The association of the gene in the biofilm-producing mechanism needs further evaluation, and further research is needed to identify the relationships between pathogens in Pasteurella multocida isolates from different species of animals and humans.