Detecting Bacteria In Space: The Good, The Bad And The Unknown

Dr. George E. Fox and Dr. Richard Willson, researchers on the National Space Biomedical Research Institute's immunology and infection team, have developed a new technology to characterize unknown bacteria. Its immediate application will be for identifying bacteria in space, but it will eventually aid in diagnosing medical conditions and detecting biological hazards on Earth.

"Understanding the bacterial environment is important for astronauts' health," said Fox, professor of biology and biochemistry at University of Houston. "Astronauts spend months in the same quarters, breathe recycled air and potentially drink recycled water; conditions that create a bacterial breeding ground. Additionally, the space environment might also have some unexpected health considerations."

Studies have shown that space conditions suppress the human immune system, making the body more susceptible to infection. Further, weightlessness and higher levels of radiation may increase the mutation rate in bacteria. This could result in making some organisms more resistant to antibiotics or perhaps causing others that are normally harmless to become infectious.

"Because of space's unidentified effects on bacteria and the immune system, we don't know which organisms will cause problems," Fox said. "However, we have developed a technique to determine an organism's approximate identity."

Their approach is based off the bacterial tree of life, which is arranged according to similarities in organisms' DNA sequences. Organisms whose DNA sequences are closely matched are more closely related than organisms whose DNA sequences are less similar. Fox and Willson have developed a method to identify the DNA sequences that are unique to small groups of bacteria.

"Current detection systems mandate that you test for an exact organism. If a problem organism is similar but not identical to the organism you are testing for, the test will show up negative," Fox said. "However, with our system, astronauts would be able to pinpoint an organism's family and significantly narrow down the possibilities of its identity."

Once Fox and Willson's device identifies the problem organism, scientists can predict the bacteria's source, like a faulty air filter or a water purifier, and fix the defective instrument for future missions.

Any kind of bacterial buildup should be avoided in the spacecraft.

"We are not specifically looking for deadly mutated bacteria," Fox said. "We are more concerned about preventing everyday infections because, if you get sick in space, you don't have a hospital around the corner for treatment. Our goal is to avoid infections with routine monitoring to keep bacteria levels low in the first place."

The routine monitoring of bacterial levels is the second component of Fox and Willson's research. Because of limited laboratory space and chemical availability in spacecrafts, they are designing an easy-to-use monitoring method for bacteria levels. Astronauts would filter the air or water, or swab a surface, to obtain the bacterial sample, and then they would test the sample for high levels of certain organisms that would indicate contamination.

"The tool will provide an early warning that the air or water purification system might not be working properly, allowing for needed repairs," said Fox. "The routine monitoring system and the bacterial identification device will help astronauts stay healthy during their time in space."

The NSBRI, funded by NASA, is a consortium of institutions studying the health risks related to long-duration space flight. The Institute's 95 research and education projects take place at 75 institutions in 22 states involving 269 investigators.