Microscopic 'astronauts' to go back in orbit

Experimental payload aboard space shuttle Endeavor to continue studies on the ability of germs to cause disease

When space shuttle Endeavor blasts off on March 11, some tiny ‘astronauts’ will piggyback onboard an experimental payload from Arizona State University’s Biodesign Institute.

The new experiment, called “Microbial Drug Resistance Virulence” is part of the STS-123 space shuttle Endeavor mission. It will continue the research studies of Cheryl Nickerson, PhD, project leader and scientist in the institute’s Center for Infectious Diseases and Vaccinology. Nickerson has been at the forefront on studying the risks of germs associated with spaceflight to the health and well being of the crew.

“Wherever people go, germs will follow,” said Nickerson, who is also an associate professor at ASU’s School of Life Sciences. Last fall, she completed a multi-institutional study that showed for the first time that microbes could be affected by spaceflight, making them more infectious pathogens. The results were from a payload flown onboard space shuttle Atlantis in 2006.

Spaceflight not only altered bacterial gene expression but also increased the ability of these organisms to cause disease, or virulence, and did so in novel ways. Compared to identical bacteria that remained on earth, the space-traveling Salmonella, a leading cause of food-borne illness, had changed expression of 167 genes. In addition, bacteria that were flown in space were almost three times as likely to cause disease when compared with control bacteria grown on the ground.

Now, her research team, which includes James Wilson, PhD, Laura Quick, Richard Davis, Emily Richter, Aurelie Crabbe and Shameema Sarker, will have an extraordinarily rare opportunity to fly a repeat experiment of their NASA payload to confirm their earlier results.

“We are very fortunate to get a follow up flight opportunity, because in spaceflight, you only get one shot for everything to go just right,” said Nickerson. “We saw unique bacterial responses in flight and these responses are giving us new information about how Salmonella causes disease. NASA is giving us the opportunity to independently replicate the virulence studies of Salmonella typhimurium from our last shuttle experiment and to do a follow-up experiment to test our hypothesis about new ways this bacteria causes disease in this unique environment.”

In the new experimental wrinkle, the team will test a hypothesis that may lead to decreasing or preventing the risk for infectious diseases to astronauts. The experiment will determine if the modulation of different ion (mineral) concentrations may be used as a novel way to counteract or block the spaceflight-associated increase in the disease-causing potential that was seen in Salmonella.