Phages are nonliving agents and require use of the host?s metabolic processes to replicate itself. In this study, interest on phage that infect and lyses staph. aurous host cells. When phage are released from the ruptured host, distinct zones of clearing (plaques) form. the original staph aureus host cells for this experiment came from a sample of raw sewage. in order to obtain the bacteriophage, a procedure of enrichment, isolation, dilution and seeding was followed, the presence of distinct plaques indicated that lytic bacteriophage had been successfully amplified, separated and grown.This study included determination of phage titre, latent period , rise period and the burst size of the phage and effect of some factors on phage titre as (temperature, ether and chloroform) .For determination of phage titre used series of dilutions(10-1, 10-2, 10-3, 10-4,10-5 10-6, 10-7, 10-8, 10-9) the dilution factor gave the best countable number of plaques was(103). this dilution factor was then used for all other experiments, the latent period , rise period and the burst size of the phage are determined by countable number of plaques and phage titre(titer: plaque-forming unit(p.f.u)) during 10,20,30,40,50, and 60 minutes . it was (28x104 , 36x104 and 51x104) during 10,20 and 30 minutes respectively in the latent period ,but it was (58x104 ,67x104 ,77x104)during 40,50,and 60 minutes respectively in the rise period .then the burst size of the phage is counted by the ratio of the phage titer after rise period to that during the latent period it was(1.422) this study also included effect of temperature on phage titre the statistical analysis revealed significantly increase P<0.05 in phage titre at the temperature37 Comparing with phage titre at the temperature 50 C° and phage titre at the temperature 65 C°. effects of ether and chloroform on number of plaques and phage titre during 5,10,15 ,20,25 ,30,35 and 40 minutes was(0.7x105 , 0.3x105 , 0 , 0 , 0 , 0, 0 and 0) respectively in ether sensitivity, but the phage titre in chloroform sensitivity was completely inactivated by chloroform treatment, the statistical analysis revealed high significant increase (P<0.05) in phage titre in normal saline comparing with phage titre in ether and chloroform sensitivity.
Introduction