This subset of genes - although most have not been directly identified as virulence genes - are more likely to be virulence-associated.
They use them to regulate the expression of virulence genes within their quorum-sensing process.
This shows true virulence genes may only be expressed during the early stages of infection.
So far, the search for virulence genes of Salmonella has yielded some surprises.
Dr. Mekalanos said he was optimistic that the discovery of virulence genes would lead to new drugs and vaccines.
It should also be possible to look at how the same virulence genes act in genetically different strains of mice.
Thus, a change in a pleiotropic immunity or virulence gene may automatically affect other traits.
There are over 40 antibiotic resistance genes identified on cassettes, also virulence genes.
Our understanding of potential sources of virulence genes will be expanded to include virtually all life on earth - at first glance a frightening prospect.
Depending on the location of the bacterium within the host organism, different activators up regulate the virulence genes.