Antibacterial activities (Bacitracin A and Polymyxin B) of lyophilized extracts from indigenous Bacillus subtilis against Staphylococcus aureus

The antibacterial compounds,which are produced from bacillus species,have a strong inhibition ability,and the composition of these compounds have not been elucidated. the aim of the present study is to explore the antibacterial activity of crude lyophilized extracts,then isolate and characterize these antibacterial. bacillus subtilis strains were isolated from damascus zone and identified by two methods which are the api chb 50 and 16s dna. staphylococcus aureus strains were isolated from clinical samples,and identified by api staph 20 and coagulase test. the crude antibacterial was extracted by flasks content lb where incubated for 72 h. in shaker incubator at 37°c at 150 rev/min,then centrifugated 12000 rev/minor 15 min. at 4 °c and filtrated the supernatants throw 0.45 μm,next frozen and lyophilized. the crude extracts were run on hplc system to separate the antibiotics. some strains of b. subtilis gave high activity against strains of s. aureus and others were not. peptides families of antibiotics were separated from lyophilized extracts of b. subtilis,and then they were identified as bacitracin a and polymyxin b. this crude extract could function as antibacterial activity against s. aureus pathogens. © 2017 jordan journal of biological sciences.