Comparisons of these sequences should help us understand why the closely related bacteria behave quite differently.
Typhoid infects 16 million people each year, killing 600,000 of them.
Julian Parkhill, of the Sanger Center, Cambridge, England, and colleagues have sequenced a strain of typhoid-causing Salmonella enterica from Vietnam that is resistant to several antibiotics.
S. enterica can burrow out of the gut and into human liver, spleen and bone marrow. Its genome reveals many genes that may adapt it to this lifestyle.
| Genomes of S. entericia and S. typhimurium have been revealed.
Michael McClelland of Sidney Kimmel Cancer Center, San Diego, and colleagues sequenced another strain, Salmonella typhimurium.
In humans, this strain causes an unpleasant but not fatal upset stomach.
In mice, its symptoms are very similar to human typhoid. This makes it a popular choice with laboratories that research Salmonella.
The sequence reveals 50 genes that code for proteins on the bacterium's surface. These are good potential vaccine or drug targets.