'Hypervirulent' salmonella could overwhelm a vaccine

Salmonella infection, which is usually caught from food or water, can lead to anything from an upset stomach to hospitalization, and it's especially dangerous in young and elderly people. There are a number of salmonella vaccines in the works, but there's nothing yet on the market, and already researchers at the University of California, Santa Barbara and in Australia have found that salmonella bacteria have the capacity to overwhelm vaccines.

The team looked at strains of Salmonella enterica, the bug behind the infection, and found that some were up to 100 times more infectious than normal (known as "hypervirulent"), and could infect and kill vaccinated animals. This is driven by altered genes in the bacterium's genome.

These bacteria are able to "hide" because they can switch between hypervirulence and normal levels of infectivity. As part of their research, the team was able to find tools that allowed them to tell the difference between the hypervirulent and normal bacteria.

While this prospect is obviously worrying, knowing the pathway that makes bacteria, especially salmonella, more virulent could point a way toward more effective vaccines.

"Now that we have identified the problem--and potential solutions--we just need to get to work," said UCSB's Douglas Heithoff, lead author of the paper.

- read the press release
- see the abstract