OBTAINING A GENETIC ATTENUATED AROA MUTANT STRAIN PASTEURELLA MULTOCIDA
The studies used the wild type P. multocida isolated in the Almaty region of the Republic of Kazakhstan from a calf who died during an outbreak of pasteurellosis. The results of studies with the aim of obtaining an attenuated strain of P. multocida by introducing auxotrophic mutations into the AroA gene are presented. The function of this gene is essential for the growth of bacteria in vivo and for the development of the infectious process. To obtain AroA mutants of P. multocida, two plasmids were constructed that carried the AroA gene with impaired function. During repeated passages of transformants on media containing kanamycin, 9 clones were selected, which according to the results of PCR analysis belonged to the species P. multocida. When studying these clones for the content of AroA gene of the mutant type, PCR products of 1922 bp in size were obtained in 3 clones, indicating the presence of a genetic construct. These clones were isolated and then cultured using the limiting dilution method. The obtained single colonies were seeded on M9 minimal medium, while the growth of all studied subclones was noted. At the final stage, the virulence of the obtained recombinant clones for white mice was studied. According to the results of the experiment, the least pathogenic clone was selected, which can be used as an anti-pasteurellosis vaccine candidate.