Precise detection of L. monocytogenes hitting its highly conserved region possessing several specific antibody binding sites.

Listeria monocytogenes, a facultative intracellular fast-growing Gram-positive food-borne pathogen, can infect immunocompromised individuals leading to meningitis, meningoencephalitis and septicaemias. From the pool of virulence factors of the organism, ActA, a membrane protein, has a critical role in the life cycle of L. monocytogenes. High mortality rate of listeriosis necessitates a sensitive and rapid diagnostic test for precise identification of L. monocytogenes. We used bioinformatic tools to locate a specific conserved region of ActA for designing and developing an antibody-antigen based diagnostic test for the detection of L. monocytogenes. A number of databases were looked for ActA related sequences. Sequences were analyzed with several online software to find an appropriate region for our purpose. ActA protein was found specific to Listeria species with no homologs in other organisms. We finally introduced a highly conserved region within ActA sequence that possess several antibody binding sites specific to L. monocytogenes. This protein sequence can serve as an antigen for designing a relatively cheap, sensitive, and specific diagnostic test for detection of L. monocytogenes.