Bacterial endotoxin is found in many bacteria, and its concentration has been used as a relative assessment of bacterial levels. However, most traditional enumeration and identification techniques require days to complete. Habitat swab samples were analyzed with an automated real-time monitor of bacterial endotoxin, called the Portable Test System (PTS). The PTS was operated by the crew during the mission. The results were then correlated with advanced microbiological analysis of the same swab samples in the laboratory following the mission. This correlation will determine if this new system can detect trends in bacterial growth that could affect crew health.
At present, there is no rapid, real-time bacterial-detection device for crew use on the International Space Station (ISS). Monitoring of bacteria onboard requires the return of swab samples for microbiological analysis on the ground. This method provides high-quality identification of bacteria onboard, but with a significant time lag between swab sampling and results. The PTS will enable the crew to obtain quick, "on-the-spot" results of bacterial levels onboard, without assistance from the ground; a factor useful for crews on long duration missions, where supply/re-supply missions may be infrequent. The crew could test key locations (such as air-conditioning vents, fluids for injection, surfaces and the water system), identify "hot-spot" areas of rapid bacterial growth at an early stage, and use cleaning procedures to prevent potential hazards to crew health.
The PTS was found to be a robust instrument for detection of bacterial levels during a mission situation. Sterile conditions were not required and the system was found to be user-friendly by the crew. At present, no such portable device is available on ISS to test bacterial levels, and all microbiological analysis must occur on the ground after extensive storage time and transportation in non-refrigerated conditions. NEEMO 5 proved to be a valuable opportunity to correlate results obtained with PTS in Aquarius with those obtained in the Microbiology Laboratory at JSC using culture methods. Results correlated well between the two methods and some bacterial species of potential health concern were identified using culture methods. Since NEEMO 5, the PTS cuvettes have been modified by Dr. Norm Wainwright (Marine Biology Lab, Woods Hole, MA) to allow the detection of fungi, gram–positive bacteria, and potentially dangerous bacterial species by modification of the antibodies used for detection.
1. Few species in the Aquarius habitat were found to be hazardous:
2. PTS performed nominally in a humid and hyperbaric environment
3. Positive correlation (0.92) between data obtained with PTS and Standard Culture methods
4. Minimum training required for crew to operate PTS
|Mission||Launch/Start Date||Landing/End Date||Duration|
|NEEMO 5||06/16/2003||06/29/2003||14 days|