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Salmonella vaccine may be result of space trip

A series of experiments conducted aboard the International Space Station may soon lead to a vaccine against food poisoning from salmonella bacteria.
Image: Salmonella
This microscopic image shows a culture of salmonella bacteria. Researchers say because the conditions of the human intestine are similar to those of microgravity, space is an ideal place to study salmonella.NASA
/ Source: Discovery Channel

A series of experiments conducted aboard the International Space Station may soon lead to a vaccine against food poisoning from salmonella bacteria.

Researchers are analyzing a batch of the bacteria brought back by the shuttle Discovery crew last month. Earlier studies showed salmonella can become more virulent in weightlessness; further investigations proved its virulence can be controlled, toggled on and off like a switch.

Now two groups are working to develop compounds for a salmonella vaccine, said space station program scientist Julie Robinson.

The studies began because NASA was concerned its astronauts might be more susceptible to food poisoning in space due to their weakened immune systems — an unfortunate, but well-documented effect of microgravity.

Then researchers discovered that microgravity changes salmonella itself, providing insight into a new way to possibly control the bacteria on Earth.

"Given that salmonella is among the leading causes of food-borne pathogens, one of the disappointments of the 21st century is that we don't have a vaccine," said Arizona State University's Cheryl Nickerson, who heads one of the research teams investigating salmonella in space.

It was Nickerson's group that identified genetic changes in space-borne salmonella which made the bacteria more virulent than identical samples on Earth. Because the environment inside the intestines is similar to weightlessness, Nickerson is hopeful her research will lead to a vaccine and other treatments for food poisoning.

The Centers for Disease Control and Prevention estimate 40,000 cases of salmonella infection are reported in the United States every year.

A second series of salmonella investigations, overseen by Timothy Hammond at the Durham Veterans Administration Medical Center in North Carolina, flew aboard the space station last year. Hammond's team is pursuing a vaccine based on the genetic changes seen in the space-borne bacteria.

"They are investigating whether you could use the virulence of the changes to develop a vaccine," Robinson told Discovery News.

Hammond's team flew four experiments, with no public results available yet, Robinson said.

The salmonella investigations are the most mature of dozens of experiments that have been conducted aboard the space station, which so far has led to 162 publications in science research journals, Robinson said.

With the station's live-aboard crew slated to double from three to six members next month, the number of experiments is expected to increase dramatically.

"A year ago we had 30 experiments over a six-month period. Now, we're already well over 100," Robinson said.