LYSOGENY AND LYSOSENSITIVITY IN SALMONELLA STRAINS

Abstract

Bacteriophages are viruses pathogenic to bacteria, that is, “bacteria eaters”. The results of the activity of the phage to bacterial cells manifests itself through the following phenomena:

(a) The bacterial cell is lysosensitive (it allows the phage to multiply, with bacterial lysis); (b) It is Lysogenic (it carries the bacteriophage in its genome and transmits it from generation to generation); (c) It is lysoresistant (it has no receptors for bacteriophages and resists to the attack of the phage). Though once believed the bacteriophages would become a universal treatment for bacterial disease, this has not proved valid from reasons like inactivation within the organism or the emergence of resistant bacteria. However, as antibioresistence is becoming more common and as the importance of establishing the filiation of the strains involved in food poisonings, the importance of bacteriophages has become actual again. To carry out this study, liquid and solid culture media has been used, young cultures of the researched strains, Petri dishes, and sets of bacteriophages obtained from lysogenic cultures. For studying lysogeny the cultures were seeded onto solid media in squares drawn on the dish and after the culture dried, drops of the liquid media culture that was surveyed for lysogeny were added. After 24h at 37C, we read the results – with clear evidence of areas of cellular lysis. To check for lysosensitivity the tested cultures were seeded onto Petri dishes and after drying the prepared phages were added. After incubation, we checked the cellular lysis areas. The findings are illustrated in photo 1 (lysogeny) and photo 2 (lysosensitivity). After completion of the tests it was revealed that a number of 6 Salmonella strains of the 45 in total (13.33%) were lysogenic and a number of 18 strains (40%) were lysosensitive. From current literature, it is evident that isolation of bacteriophages and their standardization and grouping in sets for phagic profiling has become of great importance as the method of phagic profiling is very quick, easy, and cheap when compared to genetic, biochemical, and serologic methods - and can be used complementary, with other sets of bacteriological diagnosis.