Bacteria Genomes - SHIGELLA FLEXNERI

Shigella are Gram-negative, nonmotile, nonsporeforming rod-shaped bacteria that are highly infectious agents that are transmitted by the fecal-oral route.

Shigella flexneri is a human intestinal pathogen, causing dysentery by invading the epithelium of the colon and is responsible, worldwide, for an estimated 165 million episodes of shigellosis and 1.5 million deaths per year.

The bacterium is commonly found in water polluted with human faeces. It is transmitted in contaminated food or water and through contact between people. Upon infection, humans develop severe abdominal cramps, fever, and frequent passage of bloody stools. Shigellosis is not only a significant cause of infant mortality in developing nations but maintains endemic levels of infection worldwide.

New treatments are needed for this highly infectious microbe because antibiotics are often inadequate and drug-resistant strains are on the rise. Currently, no vaccines exist and the World Health Organisation considers the development of a vaccine a priority. The publication of the genome sequence is an important step in achieving this goal.

The sequenced S. flexneri strain was isolated from a patient with severe acute shigellosis in Beijing in 1984, the bacterium has about 4,700 genes. The S. flexneri genome consists of a chromosome and a smaller DNA structure called a virulence plasmid, which contains genes important in causing disease.

References:

http://www.genome.wisc.edu/sequencing/sflex.htm
http://vm.cfsan.fda.gov/~mow/chap19.html
http://genomenewsnetwork.org/articles/11_02/shigella.shtml
Nucleic Acids Res. 30(20):4432-4441(2002)