Bacteriophages may be an alternative method of treatment for antibiotic-resistant bacteria, including mastitis in cows. Our study describes the initial isolation and bacteriological activity of bacteriophages, circulating on dairy farms, the against S. aureus var. bovis. Samples of cow’s milk secretions with signs of mastitis and sewage water were used as the study material. The isolation and production of pure bacteriophage lines were performed according to the double agar method. The method of studying a single cycle of phage reproduction was used to determine the duration of the latency period. Determination of the spectrum of the lytic activity of bacteriophages against the clinical isolates of the microorganisms was carried out by the drop method. As a result of the research, four phages, specific for S. aureus var. bovis were isolated: Phage SAvB07, Phage SAvB08, Phage SAvB12 and Phage SAvB14. The negative colonies of the isolated phages were 1–2 mm in size, rounded with clear edges, with varying degrees of transparency. The latency period of Phage SAvB14 was 35 min, with the number of active virions increasing by 8 orders. In the study on growth curves of other bacteriophages, taken in the experiment, the latency period was more than 35 min, and their titre increased by only two orders. Phage SAvB07, Phage SAvB08 and Phage SAvB12 were able to lyse the bacterial strains of S. aureus var. bovis in 25–45.6% of the cases (low lytic activity), whereas Phage SAvB14 lysed 94.1% of S. aureus strains were isolated from the cows. Studies have shown that among the bacteriophages we have studied, Phage SAvB14 with a short latency period has the best lytic action on the culture S. aureus var. bovis. The resulting bacteriophage strain can be used to create a bacteriophage-based drug for the treatment of mastitis in cows.
Наведено дослідження процесу адгезії бактерій до поверхні з різною шорсткістю залежно від розмірів і форми. Встановлено, що на поверхні нержавіючої сталі з шорсткістю 2,687±0,014 мкм, процес плівкоутворення у E. coli та S. aureus проходив однаково упродовж з 3 до 24 години та не залежав від розмірів бактерій. Це дозволяє стверджувати, що паличковидні і кокові бактерії вільно прикріпляються у западинах шорсткості та розпочинається початковий процес першої стадії формування біоплівки. Під час санітарної обробки у западинах шорсткості можуть залишатися, як кокові, так паличковидні бактерії. На поверхні сталі з шорсткістю 0,95±0,092 мкм процес плівкоутворення у S. aureus проходив інтенсивніше, ніж у E. coli. Упродовж 3 год інкубації щільність сформованих біоплівок S. aureus була в 1,2 раза більша, порівняно з біоплівками E. coli. У наступні 15 годин інкубації сформовані біоплівки S. aureus були, в середньому в 1,3 раза щільніші. Це дає підставу вважати, що S. aureus завдяки кулястій формі здатний розміщуватися у западинах шорсткості 0,95±0,092 мкм і швидше адгезуватися до поверхні. Водночас E. coli, завдяки паличковидній формі, за такої шорсткості поверхні може адгезуватися у западини тільки повздовж. Доведено, що за шорсткості поверхні 0,63±0,087 мкм інтенсивність плівкоутворення S.aureus була, в середньому в 1,4 раза швидша, ніж у E. coli. Водночас, за шорсткості 0,16±0,018 мкм процес плівкоутворення проходив однаково у S. aureus і E. coli, але біоплівки були нижчої щільності, порівняно з такими, які формувалися за шорсткості 0,63±0,087 мкм. Отже, використання обладнання у молочній промисловості з шорсткістю менше 0,5 мкм дозволить зменшення прикріплення мікроорганізмів до поверхні і зниження контамінації молочних продуктів Ключові слова: мікробна адгезія, формування біоплівок, шорсткість поверхні нержавіючої сталі, процес плівкоутворення
Objective: The objective of this study was to investigate the intensity of phage infection caused by Phage SAvB14 , which was isolated from dairy farms, depending on the initial number of Staphylococcus aureus cells in the medium. Material and methods: To evaluate the impact of the viable bacteria S. aureus var. bovis on the intensity of phage infection caused by Phage SAvB14 , 1 mg of phagolysate (phage titer 10 5 CFU/ ml) was introduced in 9 ml of nutrient broth with an appropriate amount of daily culture of S. aureus var. bovis under study. The number of viable staphylococci was determined by total viable count/ml. Results: In this experiment, we found that the intensity of phages lytic activity was dependent on the number of sensitive bacterial cells in the volume of the culture medium. Effective phage therapy requires a high concentration of phages in the medium (inflammation foci) for rapid contact of the virus with bacteria. Conclusion: When developing a phage drug to treat subclinical mastitis, it is necessary to increase the phage titer in the drug or its dosage compared to the clinical form, as there is a lower probability of phage contact with a susceptible microbial cell. Besides, at a high concentration of bacteria, there is a gradual decrease in nutrients in the medium, resulting in phages going back to the condition of lysogeny.
Science is constantly evolving and updated with current data on cell biology. The cellular aging phenomenon should be considered an evolutionary mechanism of the biological regulation of all living organisms. Factors initiating cellular aging are variable. Each cell type can respond differently to the activation factors of cellular aging. In recent decades, science has been supplemented with new data that provide a deeper understanding of cellular and molecular mechanisms of cellular aging and the formation of immune homeostasis. There is a real prospect of using effective means of its regulation. In recent years, scientists have come close to discovering the mechanisms of cellular aging. Factors and mechanisms of cell regeneration are more deeply revealed. Scientists are also better aware of the phylogeny and ontogenesis of immune processes and the role of immune factors in developing pathologies. Researchers are increasingly focusing on modern diagnostic methods and xenotherapy. However, the specific factors of immunoregulation and the interaction of microphages, macrophages, and lymphocytes with other body cells are not yet fully understood. Accordingly, this requires further in-depth study. This review reviews the current literature on cellular aging and its regulatory mechanisms. The authors also present the results of their research on the mechanisms of immune responses in reproductive pathology. They draw parallels with modern scientific theories and interpret research. We will also focus on the issues that need to be addressed in the near future for the progressive development of this field of science. Thus, the study of the mechanisms of cellular aging and the development of effective means of hay therapy today requires further painstaking work. Despite significant advances in preclinical studies, many questions remain about the practical use of the drugs. This is especially true in the medicine of oncology, neurology, and cardiology. Nevertheless, scientists will be able to use pharmacological agents to influence cell division, differentiation, and determination in the future. We also hope to have developed effective means of immunotherapy of diseases. The molecular mechanisms of cell aging and mediators involved in the mechanisms of cell aging and death are being studied in detail. The field of research contains countless fascinating studies that are sure to be discovered.
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