Isolation of bacteriophages specific for Staphylococcus aureus var. bovis

Cite this article: Horiuk, Yu. V. (2019). Isolation of bacteriophages specific for Staphylococcus aureus var. bovis. Theoretical and Applied Veterinary Medicine, 7(3), 143‒146. doi: 10.32819/2019.71025 Abstract. Bacteriophages are viruses that infect bacteria, draw the increasing attention as a control of bacterial pathogens. However, developing a successful strategy on the basis of phages requires in-depth analysis of the various parameters. The results of comparison of isolation procedures of bacteriophages specific for Staphylococcus aureus var. bovis from the secretion of cows which ill with subclinical form of mastitis are presented in the article. They can be used to create a phage preparation for the prophylaxis and veterinary treatment of mastitis. The initial stock for the obtaining of bacteriophages were samples of horned cattle secretion, which were processed according to standard procedures. For the purification of phagolysate from extraneous microflora have been used two-stage filtration (pore size of 0.45 μm), heating of tubes at a temperature of 60 ± 2°C for 30 minutes and exposure to chloroform. The lytic activity of bacteriophages as well as the morphology of the negative colonies were studied by the Gratia method. It is established that the microflora after the first passage was represented by different species, depending on the way the samples are processed. The method of purification of staphylococcal bacteriophages from bacterial cells with trichloromethane is the most effective. Yes, only Staphylococcus aureus stood out for the first passage. Many phages are unstable to chloroform. Therefore, this procedure is not entirely suitable for the initial isolation of staphylococcal bacteriophage. The extraneous flora of the phagolysate under the influence of 60 ± 2°C for 30 minutes is represented by heat-resistant bacteria: Enterococcus, Lactococcus, Bacillus. In the second passage, only the genus Enterococcus stands out. In the future, the foreign flora is not isolated. In general, the temperature treatment at the already named parameters is an efficient in quality, but long over time method. In the two-stage filtration of the phagolysate, the bacteria of the group of Escherichia coli, namely representatives of the genus Klebsiella, are isolated in the first and second passages. The use of filtration in the subsequent passage effectively purified phagolysate from extraneous microflora. The results of studies on the purification of staphylococcal bacteriophages from bacterial cells indicate the effectiveness of multi-stage filtration.