New Method Detects and Measures Bacteria

Bacteria in space, beware. New technology to monitor and identify bacteria has been developed by two researchers at the National Space Biomedical Research Institute. The institute is a NASA-funded consortium of 12 medical institutions, including Baylor College of Medicine, that are studying the health risks related to long-duration space flight, then transferring the knowledge learned to benefit patients on Earth. The Institute’s 95 research and education projects take place at 75 institutions in 22 states involving 269 investigators.

George E. Fox, Ph.D., and Richard Willson, Ph.D., researchers on the institute’s immunology and infection team, have developed a new technology to characterize unknown bacteria. The technology initially will be used to identify bacteria in space, and later will 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 the University of Houston. “Astronauts spend months in the same quarters, breathe recycled air and drink recycled water – conditions like these create a bacterial breeding ground.”

Additionally, studies show 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.

Current detection systems, he explained, mandate that an identity test be performed for an exact organism. If a problem organism is similar but not identical to the organism being testing, the test will produce a “negative” result.

“With our system,” Fox said, “astronauts would be able to pinpoint an organism’s family and significantly narrow down the possibilities of its identity.”

Their approach is based on 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 sequences are less similar. Fox and Willson’s method identifies the DNA sequences that are unique to small groups of bacteria.

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 in the spacecraft, and fix the defective instrument for future missions.

“We are 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 bacterial levels low in the first place,” Fox said.

To monitor bacterial levels, astronauts would use a tool developed by Fox and Willson to filter the air or water, or swab a surface, to obtain the bacterial sample, and then 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 may not be working properly, allowing for needed repairs,” said Fox. “Together, the routine monitoring system and the bacterial identification device will help astronauts stay healthy in space.”

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©2006 Texas Medical Center

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