Numerous completely sequenced bacterial genomes harbor prophage elements. These elements have been implicated in increasing the virulence of the host and in phage immunity. The e14 element is a defective lambdoid prophage element present at 25 min in the Escherichia coli K-12 genome. e14 is a well-characterized prophage element and has been subjected to in-depth bioinformatic analysis.
A protein-based comparative approach using BLAST helped identify lambdoid-like prophage elements in a representative set of completely sequenced bacterial genomes. Twelve putative prophage regions were identified in six different bacterial genomes. Examination of the known and newly identified prophage regions suggests that on an average, the prophage elements do not seem to occur either randomly or in a uniform manner along the genome amongst genomes of the selected pathogenic organisms.
The protein based comparative approach can be effectively used to detect lambdoid-like prophage elements in bacterial genomes. It is possible that this method can be extended to all prophage elements and can be made automated.