Document Type : Original Article


1 Agric. Microbiology Dept., Fac. of Agric., Ain Shams Univ., P.O. Box 68, Hadayek Shobra 11241, Cairo, Egypt

2 Basic and Applied Agric. Sciences Dept., Higher Institute for Agric. Co-Operation, Cairo, Egypt.


Listeria monocytogenes is a food borne pathogenic bacteria and caused a dangerous infection of humans. Six lytic bacteriophages specific to L. monocytogenes were isolated from irrigation and sewage waters and named ØLG, ØLA, ØLM, ØLD, ØLN and ØLP. The phages were propagated, and then purified by the ultracentrifugation. Morphological properties of Listeria phages showed that the phages were tailed phages, varied in their sizes and assigned to be a member of Siphoviridae (ØLG, ØLA, ØLM) and Myoviridae (ØLN, ØLD, ØLP)   families. All Listeria phages were highly stable under different temperature conditions and its thermal inactivation point was reached to 80°C. The longevity in vitro of the phages was up to 60 days, as well as phages were active at pH values ranging from 4.0 to 12.0. Listeria phages did not lose their infectivity after exposure to UV for 90 min at 35 and 53 cm distances. Results of SDS-PAGE showed that phages had 5-6 protein fragments with molecular weights of 66, 45, 37, 35, 33 and 28 kDa distributed among the six phages.