Characterization of lytic activity of on .

OBJECTIVE

The objective of this study was to investigate the intensity of phage infection caused by , which was isolated from dairy farms, depending on the initial number of cells in the medium.

MATERIAL AND METHODS

To evaluate the impact of the viable bacteria on the intensity of phage infection caused by , 1 mg of phagolysate (phage titer 10 CFU/ ml) was introduced in 9 ml of nutrient broth with an appropriate amount of daily culture of 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.