Bacteria Genomes - SALMONELLA TYPHIMURIUM

The genus Salmonella contains over 2,000 sero-species and is one of the most important pathogens in the family Enterobacteriaceae. Taxonomically, all strains of Salmonella fall within one species, S. enterica but this nomenclature has not caught on and the genus continues to be recognised by the popular species names, many named on the basis of serotyping and outbreaks.

Salmonellae are Gram-negative , facultatively anaerobic bacteria of the family Enterobacteriaceae, made up of nonspore-forming rods, usually motile with peritrichous flagella. They utilise citrate as a sole carbon source and generally ferment glucose but not sucrose or lactose.

Salmonella enterica serovar Typhimurium is the among the most common Salmonella serovars causing Salmonellosis infections in the US. In humans, Salmonellosis causes diarrhea, fever, and abdominal cramps 12 to 72 hours after infection and may last for up to 7 days. Some cases result in hospitalisation. Salmonella is readily transmitted through the faeces of people or animals. The incidence of non-typhoid salmonellosis (which is caused by Salmonella enterica typhi) is increasing worldwide, causing millions of infections and many deaths in the human population each year.

Sequencing of the genomes of two Salmonella bacteria ( S. typhimurium LT2 and S. enterica serovar Typhi (S. typhi), should lead to new ways to diagnose, treat and vaccinate against both diseases. Comparing the sequences should also clarify why the closely related bacteria behave quite differently. Typhimurium has a less alarming public image, but is a bigger health problem than typhoid, it is thought by researchers to be at least 30-fold underreported. There are probably hundreds of millions of cases every year in the world and gut-dwelling Salmonella may kill twice as many people - mostly infants and the elderly - as typhoid.

Typhimurium's sequence reveals 50 previously unknown genes that code for proteins on its surface. These are potential vaccine or drug targets as weakened versions can be used to deliver vaccines and cancer drugs.

References:

Nature 413 (6858):852-6 2001
http://www.innovations-report.com/html/reports/life_sciences/report-5573.html
http://www.life.umd.edu/classroom/bsci424/PathogenDescriptions/Salmonella.htm
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