Lawsonia intracellularis

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Higher order taxa

Phylum: Bacteria

Bacteria; Proteobacteria; Deltaproteobacteria; Desulfovibrionales; Desulfovibrionaceae; Lawsonia.

Strain: PHE/MN1-00.

(there may be additional subcategories included as well. You can just copy this information from the NCBI taxonomy page)


Genus species: Lawsonia intracellularis

Description and significance

Lawsonia Intracellularis is a bacterial pathogen which causes disease in a wide range of animals, mainly pigs. The bacterial pathogen invades the intestinal epithelial cells which causes hyperplasia of the infected cells which leads to the process of disease pathogenesis. Lawsonia intracelluaris is an intracellular enterophathogen that is the cause of intestinal hyperplasia which include proliferative enteropathy, intestinal adenomatosis, and ileitis. Lawsonia intracellularis though primarily recognized in pigs, is spreading to a wide range of mammals. With a 16SrRNA gene sequence, Lawsonia intracellularis is related to Desulfovibio, a sulfate-reducing bacteria and Bilophila wadsworthia.

Genome structure

Lawsonia intracellularis is made up of a circular chromosome and the length is 1,457,619 nucleotides. The genomic content includes 1,719,014 nucleotides. It had 1, 337 protein genes and 49 RNA genes.

Cell structure and metabolism

The structure of Lawsonia intracellularis reveals non-spore-forming curved rods. It contains gram-negative cells that are able to retain carbol-fushsin when stained using the Ziehl-Neelsen method. It is nonpifmented and nonflagellated. Through the Ziehl-Neelsen method the cell wall of a gram-negative is shown as well as the protoplasmic structure of a prokaryote. The cells replicate within the cytplasm and are not enclosed by membrane-bound vacuoles. This occurs in epitheilial cells of pigs.


Natural infection has not been detected in either wild or laboratory mice however, the former represent a potential reservoir; hence, our findings have further implications for the ecology and epidemiology of PE, particularly in pigs, where the environment is likely to be cohabited by rodents. Although pigs have been considered the major susceptible animal, it is becoming increasingly apparent that L. intracellularis has a broad host range which is potentially wider than currently known. Despite evidence of infection in primates, there is currently no direct evidence that L. intracellularis can infect humans, although one report has suggested a link with human disease. In view of the known broad host range of L. intracellularis and the wide spectrum in clinical presentation we should remain alert to the possibility that the range of susceptible species may broaden further and may incorporate humans.


Lawsonia intracellularis is an intracellular bacterial pathogen which cause intestinal hyperplasia in a wide range of mammalian and avian species.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research