On the issue of isolating a pure culture of the causative agent of pasteurellosis Pasteurella Multocida

Abstract

The article presents an analytical review on the isolation of a pure culture of the pasteurellosis pathogen Pasteurella multocida according to literature data and the results of our own research. On the basis of new knowledge in the etiology of pasteurellosis, the disadvantages of the traditional method have been identified and the fundamental distinctive features of a new technical solution for the method of isolating a pure culture of P. multocida of the first generation after in vivo have been established. For its application, a standard of conditions has been formulated. To ensure the uniformity of the conditions of the methodology for the isolation, assessment and application of a pure culture (strain) of the P. multocida pasteurellosis pathogen, a method (standard) has been developed and proposed for laboratory practice. The method, including obtaining the first generation of a microorganism on an artificial environment, differs in that an individual infected naturally or intranasally or orally on the mucous membrane of the nasal, oral, pharyngeal cavities and an individual selected from a bird or rabbit, which has died from pasteurellosis, weighing 350 g after 3 h (at 20 ± 1 ° C of cooling the corpse), open, take a blood sample from the heart and add it to sterile water at a temperature of 20 ± 1 ° C in a ratio of 1: 9 by volume, shake the precipitate and transfer to a suspension, then centrifuge at 1500 rpm/ min 5 min; the supernatant liquid as a pasteurella isolate from blood in a dilution of 10-1 is diluted to 10-2, 10- 3 and inoculated at a temperature of 20±1°C on nutrient broth and nutrient agar, the crops are cultivated for 9-19 h at 37°C and 1 h at 20°C. The resulting culture is assessed pure according to strictly typical morphology of continuous growth and uniform colonies of the S-form, identical cocco- and diplococcal-like encapsulated cells in the microscope fields of view, as well as high virulence for susceptible laboratory animals and birds and with a characteristic pronounced property of microbial antagonism.