Executive Summary : | Six Salmonella typhi specific phages and six Salmonella typhimurium specific have been isolated from different geographical regions of the State of Tamil Nadu. Phages were isolated and purified as per the standard methods. The phages of Salmonella typhi were highly stable under different physiological conditions. They were stable even up to pH 4, whereas the phages of Salmonella typhimurium were stable only upto pH 5. The Salmonella typhi phages have a very broad host range compared to phages of S. typhimurium. All the phages seemed to possess similar molecular make up. The restriction digestion analysis of the genomes and the protein profile of the phages did not produced significant differences among phages to diversify them. The phages were highly specific for Enterobacteriaceae for their host range. All of them were highly stable between the pH 4 - 9, and up to the temperature 45°C. But evident differences were observed among the physiological properties between the phages especially in their host range and lytic cycle. This difference shows that the phages were similar in its molecular makeup, but diversified in their physiological properties. A novel, simplified SHIME system was designed and validated. The phages were stable in the SHIME system after the addition of antacid into the system. Hence, these isolated phages can be used as a therapeutic agent to treat Salmonellosis as these phages were highly stable under extreme physiological conditions. The efficiency of the phages during the phage therapy can be increased on oral administration after intake of the antacid. |