Characterization of the biological properties of bacteriophages Staphylococcus aureus variant bovis

• Main Author: Yu. V. Horiuk
• Format: Article
• Language: English
• Published: Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies Lviv 2019-12-01
• Series: Науковий вісник Львівського національного університету ветеринарної медицини та біотехнологій імені С.З. Ґжицького: Серія Ветеринарні науки
• Subjects: mastitis, bacteriophages, staphylococcus aureus, lytic activity, temperature, ph.
• Online Access: https://nvlvet.com.ua/index.php/journal/article/view/3858
• ISSN: 2518-7554; 2518-1327

Cattle mastitis is the main cause of economic losses in milk production worldwide, and Staphylococcus aureus is the pathogen that causes it most. Bacteriophages may be an alternative treatment for this disease. In this study, we studied the effect of temperature and pH on the lytic activity of bacteriophages isolated from cows with signs of mastitis. The isolation and production of pure phage lines were performed on an indicator culture of Staphylococcus aureus var. bovis 1491f conventional methods. The following phages were isolated and labeled: Phage SAvB07, Phage SAvB08, Phage SAvB12, Phage SAvB14. To determine the effect of temperature and pH, aliquots after the action of these factors were sown by the double agar method at regular intervals. The study found that phage lytic activity was temperature dependent. Thus, under the influence of temperature 45 °C after 30 minutes of action, it decreased by 3.0–3.4 times for bacteriophages Phage SAvB07, Phage SAvB08, Phage SAvB12 and after one hour was 2.4–12.6%. Phage SAvB14 strain was more resistant to temperature. Its activity decreased by only 67.6% during the analyzed period. With higher temperatures (55–65 °C), the intensity of phage infection decreased significantly, but remained stable. The most resistant to the effects of temperature was Phage SAvB14 – its activity was on average higher by 15.6–33.9% compared with other phages taken in the experiment. The results of our studies on the effect of pH on the reproduction of phages showed that the maximum number of phage virions was observed at pH 6 7. However, the most resistant to acidity was the phage strain Phage SAvB14, compared with other strains taken in the experiment. Therefore, the bacteriophage Phage SAvB14 exhibited the greatest stability and has considerable potential for in vivo use in the treatment of mastitis of cows caused by Staphylococcus aureus.