BASAVARAJ AWATIN. A. PATILS. M. KARTIKESHJAGANNATH RAOSURYAKANTH2020-01-132020-01-132018-07http://krishikosh.egranth.ac.in/handle/1/5810140279Staphylococcus aureus is a common bacterium found on body of bovines but if it bypasses the udder protection and enters the teat, it can cause mastitis which is a highly economic important disease. In this study from 88 mastitis suspected milk samples, 45 Staphylococcus spps were isolated. Based on cultural, morphological and biochemical characters, the isolates were found tentatively as Staphylococcus aureus, indicating 51.13% (46.66% in Cattle, 60.71% in Buffaloes) of Staphylococcus aureus mastitis in bovine mastitis in Bidar district. Further the isolates were subjected for antibiogram study and it was found that Staphylococcus aureus has developed Multi Drug Resistance to many commonly used antimicrobials in the field. It is this antibiotic resistance problem, which has made Staphylococcus aureus as one of the major hurdle for dairy farming all over the world. To overcome this problem and to control and treat Staphylococcus aureus mastitis, one such option is phage therapy. In this study 4 phages were isolated and characterized from 32 sewage samples and tentatively named as SSPh1, SSPh2, SSPh3 and SSPh4. The phages SSPh1 and SSPh2 produced clear 1-2 mm plaques, whereas phages SSPh3 and SSPh4 produced 2-3 mm clear plaques and all were able to produce good number of plaques at 108 to 1010 dilutions, indicating their high infective and strong lytic character. On assessing the host range and killing potential of newly isolated phages, it was found that all phages were narrow spectrum and Phage SSPh4 was found to be monovalent in nature. None of the phages were able to lyse other species of bacteria indicating their high specificity for Staphylococcus aureus. These isolated Staphylococcus aureus phages can be potentially exploited for phage therapy as well as for phage typing as an effective tool to control and treat Staphylococcus aureus mastitis with further detailed study.ennullThesis